1
2Bristol Emulations
3------------------
4
5This is a write-up of each of the emulated synthesisers. The algorithms
6employed were 'gleaned' from a variety of sources including the original
7owners manuals, so they may be a better source of information. The author
8has owned and used a selection but far from all of the originals. Some of them
9were built just from descriptions of their operation, or from understanding
10how synths work - most of them were based on the Mini Moog anyway. Many of
11the synths share components: the filter covers most of them, the Prophets and
12Oberheims share a common oscillator and the same LFO is used in many of them.
13Having said that each one differs considerably in the resulting sound that is
14generated, more so than initially expected. Each release refines each of the
15components and the result is that all emulations benefit from the improvements.
16All the emulations have distinctive sounds, not least due to that the original
17instruments used different modulations and mod routing.
18The filter, which is a large defining factor in the tonal qualities of any
19synth, is common to all the emulations. The filter implements a few different
20algorithms and these do separate each of the synths: the Explorer layering
21two low pass filters on top of each other: the OB-Xa using different types
22depending on 'Pole' selection. Since release 0.20.8 the emulator has had a
23Houvillainen non-linear ladder filter integrated which massively improves
24the quality at considerable expense to the CPU.
25There is one further filter algorithm used solely for the Leslie rotary
26emulator crossover, this is a butterworth type filter.
27
28Bristol is in no way related to any of the original manufacturers whose
29products are emulated by the engine and represented by the user interface,
30bristol does not suggest that the emulation is a like representation of the
31original instrument, and the author maintains that if you want the original
32sound then you are advised to seek out the original product. Alternatively a
33number of the original manufacturers now provide their own vintage collections
34which are anticipated to be more authentic. All names and trademarks used by
35Bristol are ownership of the respective companies and it is not inteded to
36misappropriate their use here. If you have concerns you are kindly requested
37to contact the author.
38
39The write-up includes the parameter operations, modulations, a description of
40the original instrument and a brief list of the kind of sounds you can expect
41by describing a few of the well known users of the synth.
42
43Several emulations have not been written up. Since the APR 2600 was implemented
44it became a rather large job to actually describe what was going on. If you
45really want to know about the synths that are not in this document then you
46might want to search for their owners manuals.
47
48All emulations are available from the same engine, just launch multiple GUIs
49and adjust the midi channels for multi timbrality and layering.
50
51It is noted here that the engine is relatively 'dumb'. Ok, it generates a very
52broad range of sounds, currently about 25 different synthesisers and organs,
53but it is not really intelligent. Memories are a part of the GUI specification
54- it tells the engine which algorithm to use on which MIDI channel, then it
55calls a memory routine that configures all the GUI controllers and a side effect
56of setting the controllers is that their values are sent to the engine. This is
57arguably the correct model but it can affect the use of MIDI master keyboards.
58The reason is that the GUI is really just a master keyboard for the engine and
59drives it with MIDI SYSEX messages over TCP sessions. If you were to alter the
60keyboard transpose, for example, this would result in the GUI sending different
61'key' numbers to the engine when you press a note. If you were already driving
62the synth from a master keyboard then the transpose button in the Brighton GUI
63would have no effect - the master keyboard would have to be transposed instead.
64This apparent anomaly is exacerbated by the fact that some parameters still are
65in the engine, for example master tuning is in the engine for the pure fact that
66MIDI does not have a very good concept of master tuning (only autotuning).
67Irrespective of this, bristol is a synthesiser so it needs to be played,
68tweaked, driven. If you think that any of the behaviour is anomalous then let
69me know. One known issue in this area is that if you press a key, transpose
70the GUI, then release the key - it will not go off in the engine since the GUI
71sends a different key code for the note off event - the transposed key. This
72cannot be related to the original keypress. This could be fixed with a MIDI all
73notes off event on 'transpose', but I don't like them. Also, since the 0.20
74stream the problem only affects a few of the emulations, the rest now sending
75a transpose message to the engine and letting it do the work.
76
77Since release 0.30.6 the engine correctly implements monophonic note logic.
78Prior to this the whole engine was polyphonic and playing with one voice only
79gave last note preference which dramatically affects playing styles - none of
80the cool legato effects of the early monophonics. The quoted release fix this
81limitation where the engine will keep a keymap of all played keys (one per
82emulation) when started with a single voice and uses this map to provide
83consistent note precedence, high note logic, low note logic or just using the
84previously implemented last note logic. In this release the keymap was only
85maintained with monophonic emulations, this is a potential extension as even
86in polyphonic mode it would be useful for arpeggiation (which is currently
87implemented using a FIFO rather than an ordered keymap).
88
89
90
91
92 Moog Mini
93 ---------
94
95It is perhaps not possible to write up who used this synth, the list is endless.
96Popular as it was about the first non-modular synthesiser, built as a fixed
97configuration of the racked or modular predecessors.
98
99Best known at the time on Pink Floyd 'Dark Side of the Moon' and other albums.
100Rick Wakeman used it as did Jean Michel Jarre. Wakefield could actually
101predict the sound it would make by just looking at the settings, nice to be
102able to do if a little unproductive but it went to show how this was treated
103as an instrument in its own right. It takes a bit of work to get the same sweet,
104rich sounds out of the emulation, but it can be done with suitable tweaking.
105
106The original was monophonic, although a polyphonic version was eventually made
107after Moog sold the company - the MultiMoog. This emulation is more comparable
108to that model as the sound is a bit thinner and can be polyphonic. The design
109of this synth became the pole bearer for the following generations: it had
110three oscillators, one of which could become a low frequency modulator. They
111were fed into a mixer with a noise source, and were then fed into a filter
112with 2 envelope generators to contour the wave. Modulation capabilities were
113not extensive, but interestingly enough it did have a frequency modulation (FM)
114capability, eventually used by Yamaha to revolutionise the synthesiser market
115starting the downfall of analogue synthesis twenty years later.
116
117All the analogue synths were temperature sensitive. It was not unusual for the
118synths to 'detune' between sound test and performance as the evening set in.
119To overcome this they could optionally produce a stable A-440Hz signal for
120tuning the oscillators manually - eventually being an automated option in the
121newer synths. Whilst this digital version has stable frequency generation the
122A-440 is still employed here for the sake of it.
123
124Modifiers and mod routing are relatively simple, Osc-3 and noise can be mixed,
125and this signal routed to the oscillator 1 and 2 frequency or filter cutoff.
126
127The synth had 5 main stages as follows:
128
129Control:
130
131 Master tuning: up/down one note.
132
133 Glide: (glissando, portamento). The rate at which one key will change its
134 frequency to the next played key, 0 to 30 seconds.
135
136 Mod: source changes between Osc-3 and noise.
137
138 Release: The envelope generators had only 3 parameters. This governed whether
139 a key would release immediately or would use Decay to die out.
140
141 Multi: Controls whether the envelope will retrigger for each new keypress.
142
143Oscillators:
144
145 There are three oscillators. One and two are keyboard tracking, the third
146 can be decoupled and used as an LFO modulation source.
147
148 Oscillator 1:
149 Octave step from 32' to 1'.
150 Waveform selection: sine/square/pulse/ramp/tri/splitramp
151 Mod: controls whether Osc-3/noise modulates frequency
152
153 Oscillator 2:
154 Octave step from 32' to 1'.
155 Fine tune up/down 7 half notes.
156 Waveform selection: sine/square/pulse/ramp/tri/splitramp
157 Mod: controls whether Osc-3/noise modulates frequency
158
159 Oscillator 3:
160 Octave step from 32' to 1'.
161 Fine tune up/down 7 half notes.
162 Waveform selection: sine/square/pulse/ramp/tri/splitramp
163 LFO switch to decouple from keytracking.
164
165Mixer:
166
167 Gain levels for Oscillator 1/2/3
168 Mixing of the external input source into filter
169 Noise source with white/pink switch.
170
171 Note: The level at which Osc-3 and noise modulates sound depends on its
172 gain here, similarly the noise. The modulator mix also affects this, but
173 allows Osc-3 to mod as well as sound. The modwheel also affect depth.
174
175Filter:
176
177 Cutoff frequency
178
179 Emphasis (affects Q and resonance of filter).
180
181 Contour: defines how much the filter envelope affects cutoff.
182
183 Mod - Keyboard tracking of cutoff frequency.
184
185 Mod - Osc-3/noise modulation of cutoff frequency.
186
187Contour:
188
189 The synth had two envelope generators, one for the filter and one for the
190 amplifier. Release is affected by the release switch. If off the the sound
191 will release at the rate of the decay control.
192
193 Attack: initial ramp up of gain.
194
195 Decay: fall off of maximum signal down to:
196
197 Sustain: gain level for constant key-on level.
198
199 Key: Touch sensitivity of amplifier envelope.
200
201Improvements to the Mini would be some better oscillator waveforms, plus an
202alternative filter as this is a relatively simple synthesiser and could do
203with a warmer filter (this was fixed with integration of the houvillanen filters
204although the do consume a lot of CPU to do it).
205
206The Output selection has a Midi channel up/down selector and memory selector.
207To read a memory either use the up/down arrows to go to the next available
208memory, or type in a 3 digit number on the telephone keypad and press 'L' for
209load or 'S' for save.
210
211As of release 0.20.5 Vasiliy Basic contributed his Mini memory banks and they
212are now a part of the distribution:
213
214Programs for Bristol's "Mini" (from 50 to 86 PRG)
215
216List of programs:
217
218 -Melodic-
219 50 - Trumpet
220 51 - Cello
221 52 - Guitar 1
222 53 - Guitar 2
223 54 - Fingered Bass
224 55 - Picked Bass
225 56 - Harmonica
226 57 - Accordion
227 58 - Tango Accordion
228 59 - Super Accordion
229 60 - Piano
230 61 - Dark Organ
231 62 - Flute
232 63 - Music Box
233 64 - Glass Xylo
234 65 - Glass Pad
235 66 - Acid Bass
236
237 -Drums-
238 67 - Bass Drum 1
239 68 - Bass Drum 2
240 69 - Bass Drum 3
241 70 - Bass Drum 4
242 71 - Tom
243 72 - Snare 1
244 73 - Snare 2
245 74 - Snare 3
246 75 - Snare 4
247 76 - Cl HH 1
248 77 - Op HH 1
249 78 - Crash Cym 1
250 79 - Crash Cym 2
251 80 - Cl HH 2
252 81 - Op HH 2
253
254 -FX-
255 82 - Sea Shore
256 83 - Helicopter 1
257 84 - Helicopter 2
258 85 - Bird Tweet
259 86 - Birds Tweet
260
261
262
263
264 Sequential Circuits Prophet-5
265 Sequential Circuits Prophet-52 (the '5' with chorus)
266 ----------------------------------------------------
267
268Sequential circuits released amongst the first truly polyphonic synthesisers
269where a group of voice circuits (5 in this case) were linked to an onboard
270computer that gave the same parameters to each voice and drove the notes to
271each voice from the keyboard. The device had some limited memories to allow
272for real live stage work. The synth was amazingly flexible regaring the
273oscillator options and modulation routing, producing some of the fattest
274sounds around. They also had some of the fattest pricing as well, putting it
275out of reach of all but the select few, something that maintained its mythical
276status. David Sylvian of Duran Duran used the synth to wide acclaim in the
277early 80's as did many of the new wave of bands.
278
279The -52 is the same as the -5 with the addition of a chorus as it was easy, it
280turns the synth stereo for more width to the sound, and others have done it on
281the Win platform.
282
283The design of the Prophet synthesisers follows that of the Mini Moog. It has
284three oscillators one of them as a dedicated LFO. The second audio oscillator
285can also function as a second LFO, and can cross modulate oscillator A for FM
286type effects. The audible oscillators have fixed waveforms with pulse width
287modulation of the square wave. These are then mixed and sent to the filter with
288two envelopes, for the filter and amplifier.
289
290Modulation bussing is quite rich. There is the wheel modulation which is global,
291taking the LFO and Noise as a mixed source, and send it under wheel control to
292any of the oscillator frequency and pulse width, plus the filter cutoff. Poly
293mods take two sources, the filter envelope and Osc-B output (which are fully
294polyphonic, or rather, independent per voice), and can route them through to
295Osc-A frequency and Pulse Width, or through to the filter. To get the filter
296envelope to actually affect the filter it needs to go through the PolyMod
297section. Directing the filter envelope to the PW of Osc-A can make wide, breathy
298scanning effects, and when applied to the frequency can give portamento effects.
299
300LFO:
301
302 Frequency: 0.1 to 50 Hz
303 Shape: Ramp/Triangle/Square. All can be selected, none selected should
304 give a sine wave (*)
305
306 (*) Not yet implemented.
307
308Wheel Mod:
309
310 Mix: LFO/Noise
311 Dest: Osc-A Freq/Osc-B Freq/Osc-A PW/Osc-B PW/Filter Cutoff
312
313Poly Mod: These are affected by key velocity.
314
315 Filter Env: Amount of filter envelope applied
316 Osc-B: Amount of Osc-B applied:
317 Dest: Osc-A Freq/Osc-A PW/Filter Cutoff
318
319Osc-A:
320
321 Freq: 32' to 1' in octave steps
322 Shape: Ramp or Square
323 Pulse Width: only when Square is active.
324 Sync: synchronise to Osc-B
325
326Osc-B:
327
328 Freq: 32' to 1' in octave steps
329 Fine: +/- 7 semitones
330 Shape: Ramp/Triangle/Square
331 Pulse Width: only when Square is active.
332 LFO: Lowers frequency by 'several' octaves.
333 KBD: enable/disable keyboard tracking.
334
335Mixer:
336
337 Gain for Osc-A, Osc-B, Noise
338
339Filter:
340
341 Cutoff: cuttof frequency
342 Res: Resonance/Q/Emphasis
343 Env: amount of PolyMod affecting to cutoff.
344
345Envelopes: One each for PolyMod (filter) and amplifier.
346
347 Attack
348 Decay
349 Sustain
350 Release
351
352Global:
353
354 Master Volume
355 A440 - stable sine wave at A440 Hz for tuning.
356 Midi: channel up/down
357 Release: release all notes
358 Tune: autotune oscillators.
359 Glide: amount of portamento
360
361 Unison: gang all voices to a single 'fat' monophonic synthesiser.
362
363This is one of the fatter of the Bristol synths and the design of the mods
364is impressive (not my design, this is as per sequential circuits spec). Some
365of the cross modulations are noisy, notably 'Osc-B->Freq Osc-A' for square
366waves as dest and worse as source.
367
368The chorus used by the Prophet-52 is a stereo 'Dimension-D' type effect. The
369signal is panned from left to right at one rate, and the phasing and depth at
370a separate rate to generate subtle chorus through to helicopter flanging.
371
372Memories are loaded by selecting the 'Bank' button and typing in a two digit
373bank number followed by load. Once the bank has been selected then 8 memories
374from the bank can be loaded by pressing another memory select and pressing
375load. The display will show free memories (FRE) or programmed (PRG).
376
377
378
379
380 Yamaha DX-7
381 -----------
382
383Released in the '80s this synth quickly became the most popular of all time.
384It was the first fully digital synth, employed a revolutionary frequency
385modulated algorithm and was priced much lower than the analogue monsters
386that preceded it. Philip Glass used it to wide effect for Miami Vice, Prince
387had it on many of his albums, Howard Jones produced albums filled with its
388library sounds. The whole of the 80's were loaded with this synth, almost to
389the point of saturation. There was generally wide use of its library sounds
390due to the fact that it was nigh on impossible to programme, only having entry
391buttons and the algorithm itself was not exactly intuitive, but also because
392the library was exceptional and the voices very playable. The emulation is a
3936 operator per voice, and all the parameters are directly accessible to ease
394programming.
395
396The original DX had six operators although cheaper models were release with
397just 4 operators and a consequently thinner sound. Each operator is a sine
398wave oscillator with its own envelope generator for amplification and a few
399parameters that adjusted its modulators. It used a number of different
400algorithms where operators were mixed together and then used to adjust the
401frequency of the next set of operators. The sequence of the operators affected
402the net harmonics of the overall sound. Each operator has a seven stage
403envelope - 'ramp' to 'level 1', 'ramp' to 'level 2', 'decay' to 'sustain',
404and finally 'release' when a key is released. The input gain to the frequency
405modulation is controllable, the output gain is also adjustable, and the final
406stage operators can be panned left and right.
407
408Each operator has:
409
410 Envelope:
411
412 Attack: Ramp rate to L1
413 L1: First target gain level
414 Attack: Ramp rate from L2 to L2
415 L2: Second target gain level
416 Decay: Ramp rate to sustain level
417 Sustain: Continuous gain level
418 Release: Key release ramp rate
419
420 Tuning:
421
422 Tune: +/- 7 semitones
423 Transpose: 32' to 1' in octave increments
424
425 LFO: Low frequency oscillation with no keyboard control
426
427 Gain controls:
428
429 Touch: Velocity sensitivity of operator.
430
431 In gain: Amount of frequency modulation from input
432 Out gain: Output signal level
433
434 IGC: Input gain under Mod control
435 OGC: Output gain under Mod control
436
437 Pan: L/R pan of final stage operators.
438
439Global and Algorithms:
440
441 24 different operator staging algorithms
442 Pitchwheel: Depth of pitch modifier
443 Glide: Polyphonic portamento
444 Volume
445 Tune: Autotune all operators
446
447Memories can be selected with either submitting a 3 digit number on the keypad,
448or selecting the orange up/down buttons.
449
450An improvement could be more preset memories with different sounds that can
451then be modified, ie, more library sounds. There are some improvements that
452could be made to polyphonic mods from key velocity and channel/poly pressure
453that would not be difficult to implement.
454
455The addition of triangle of other complex waveforms could be a fun development
456effort (if anyone were to want to do it).
457
458The DX still has a prependancy to seg fault, especially when large gains are
459applied to input signals. This is due to loose bounds checking that will be
460extended in a present release.
461
462
463
464
465 Roland Juno-60
466 --------------
467
468Roland was one of the main pacemakers in analogue synthesis, also competing
469with the Sequential and Oberheim products. They did anticipate the moving
470market and produced the Juno-6 relatively early. This was one of the first
471accessible synths, having a reasonably fat analogue sound without the price
472card of the monster predecessors. It brought synthesis to the mass market that
473marked the decline of Sequential Circuits and Oberheim who continued to make
474their products bigger and fatter. The reduced price tag meant it had a slightly
475thinner sound, and a chorus was added to extend this, to be a little more
476comparable.
477
478The synth again follows the Mini Moog design of oscillators into filter into
479amp. The single oscillator is fattened out with harmonics and pulse width
480modulation. There is only one envelope generator that can apply to both the
481filter and amplifier.
482
483Control:
484
485 DCO: Amount of pitch wheel that is applied to the oscillators frequency.
486 VCF: Amount of pitch wheel that is applied to the filter frequency.
487
488 Tune: Master tuning of instrument
489
490 Glide: length of portamento
491
492 LFO: Manual control for start of LFO operation.
493
494Hold: (*)
495
496 Transpose: Up/Down one octave
497 Hold: prevent key off events
498
499LFO:
500
501 Rate: Frequency of LFO
502 Delay: Period before LFO is activated
503 Man/Auto: Manual or Automatic cut in of LFO
504
505DCO:
506
507 LFO: Amount of LFO affecting frequency. Affected by mod wheel.
508 PWM: Amount of LFO affecting PWM. Affected by mod wheel.
509
510 ENV/LFO/MANUAL: Modulator for PWM
511
512 Waveform:
513 Pulse or Ramp wave. Pulse has PWM capabily.
514
515 Sub oscillator:
516 On/Off first fundamental square wave.
517
518 Sub:
519 Mixer for fundamental
520
521 Noise:
522 Mixer of white noise source.
523
524HPF: High Pass Filter
525
526 Freq:
527 Frequency of cutoff.
528
529VCF:
530
531 Freq:
532 Cutoff frequency
533
534 Res:
535 Resonance/emphasis.
536
537 Envelope:
538 +ve/-ve application
539
540 Env:
541 Amount of contour applied to cutoff
542
543 LFO:
544 Depth of LFO modulation applied.
545
546 KBD:
547 Amount of key tracking applied.
548
549VCA:
550
551 Env/Gate:
552 Contour is either gated or modulated by ADSR
553
554 Level:
555 Overall volume
556
557ADSR:
558
559 Attack
560 Decay
561 Sustain
562 Release
563
564Chorus:
565
566 8 Selectable levels of Dimension-D type helicopter flanger.
567
568* The original instrument had a basic sequencer on board for arpeggio effects
569on each key. In fact, so did the Prophet-10 and Oberheims. This was only
570implemented in 0.10.11.
571
572The LFO cut in and gain is adjusted by a timer and envelope that it triggers.
573
574The Juno would improve from the use of the prophet DCO rather than its own one.
575It would require a second oscillator for the sub frequency, but the prophet DCO
576can do all the Juno does with better resampling and PWM generation.
577
578
579
580
581 Moog Voyager (Bristol "Explorer")
582 ---------------------------------
583
584This was Robert Moog's last synth, similar in build to the Mini but created
585over a quarter of a century later and having far, far more flexibility. It
586was still monophonic, a flashback to a legendary synth but also a bit like
587Bjorn Borg taking his wooden tennis racket back to Wimbledon long after having
588retired and carbon fibre having come to pass. I have no idea who uses it and
589Bjorn also crashed out in the first round. The modulation routing is exceptional
590if not exactly clear.
591
592The Voyager, or Bristol Explorer, is definitely a child of the Mini. It has
593the same fold up control panel, three and half octave keyboard and very much
594that same look and feel. It follows the same rough design of three oscillators
595mixed with noise into a filter with envelopes for the filter and amplifier.
596In contrast there is an extra 4th oscillator, a dedicated LFO bus also Osc-3
597can still function as a second LFO here. The waveforms are continuously
598selected, changing gradually to each form: bristol uses a form of morphing
599get get similar results. The envelopes are 4 stage rather than the 3 stage
600Mini, and the effects routing bears no comparison at all, being far more
601flexible here.
602
603Just because its funny to know, Robert Moog once stated that the most difficult
604part of building and releasing the Voyager was giving it the title 'Moog'. He
605had sold his company in the seventies and had to buy back the right to use his
606own name to release this synthesiser as a Moog, knowing that without that title
607it probably would not sell quite as well as it didn't.
608
609Control:
610
611 LFO:
612 Frequency
613 Sync: LFO restarted with each keypress.
614
615 Fine tune +/- one note
616 Glide 0 to 30 seconds.
617
618Modulation Busses:
619
620 Two busses are implemented. Both have similar capabilities but one is
621 controlled by the mod wheel and the other is constantly on. Each bus has
622 a selection of sources, shaping, destination selection and amount.
623
624 Wheel Modulation: Depth is controller by mod wheel.
625
626 Source: Triwave/Ramp/Sample&Hold/Osc-3/External
627 Shape: Off/Key control/Envelope/On
628 Dest: All Osc Frequency/Osc-2/Osc-3/Filter/FilterSpace/Waveform (*)
629 Amount: 0 to 1.
630
631 Constant Modulation: Can use Osc-3 as second LFO to fatten sound.
632
633 Source: Triwave/Ramp/Sample&Hold/Osc-3/External
634 Shape: Off/Key control/Envelope/On
635 Dest: All Osc Frequency/Osc-2/Osc-3/Filter/FilterSpace/Waveform (*)
636 Amount: 0 to 1.
637
638 * Destination of filter is the cutoff frequency. Filter space is the
639 difference in cutoff of the two layered filters. Waveform destination
640 affects the continuously variable oscillator waveforms and allows for
641 Pulse Width Modulation type effects with considerably more power since
642 it can affect ramp to triangle for example, not just pulse width.
643
644Oscillators:
645
646 Oscillator 1:
647 Octave: 32' to 1' in octave steps
648 Waveform: Continuous between Triangle/Ramp/Square/Pulse
649
650 Oscillator 2:
651 Tune: Continuous up/down 7 semitones.
652 Octave: 32' to 1' in octave steps
653 Waveform: Continuous between Triangle/Ramp/Square/Pulse
654
655 Oscillator 3:
656 Tune: Continuous up/down 7 semitones.
657 Octave: 32' to 1' in octave steps
658 Waveform: Continuous between Triangle/Ramp/Square/Pulse
659
660 Sync: Synchronise Osc-2 to Osc-1
661 FM: Osc-3 frequency modulates Osc-1
662 KBD: Keyboard tracking Osc-3
663 Freq: Osc-3 as second LFO
664
665Mixer:
666
667 Gain levels for each source: Osc-1/2/3, noise and external input.
668
669Filters:
670
671 There are two filters with different configuration modes:
672
673 1. Two parallel resonant lowpass filters.
674 2. Serialised HPF and resonant LPF
675
676 Cutoff: Frequency of cutoff
677 Space: Distance between the cutoff of the two filters.
678 Resonance: emphasis/Q.
679 KBD tracking amount
680 Mode: Select between the two operating modes.
681
682Envelopes:
683
684 Attack
685 Decay
686 Sustain
687 Release
688
689 Amount to filter (positive and negative control)
690
691 Velocity sensitivity of amplifier envelope.
692
693Master:
694
695 Volume
696 LFO: Single LFO or one per voice (polyphonic operation).
697 Glide: On/Off portamento
698 Release: On/Off envelope release.
699
700The Explorer has a control wheel and a control pad. The central section has
701the memory section plus a panel that can modify any of the synth parameters as
702a real time control. Press the first mouse key here and move the mouse around
703to adjust the controls. Default values are LFO frequency and filter cutoff
704but values can be changed with the 'panel' button. This is done by selecting
705'panel' rather than 'midi', and then using the up/down keys to select parameter
706that will be affected by the x and y motion of the mouse. At the moment the
707mod routing from the pad controller is not saved to the memories, and it will
708remain so since the pad controller is not exactly omnipresent on MIDI master
709keyboards - the capabilities was put into the GIU to be 'exact' to the design.
710
711This synth is amazingly flexible and difficult to advise on its best use. Try
712starting by mixing just oscillator 1 through to the filter, working on mod
713and filter options to enrich the sound, playing with the oscillator switches
714for different effects and then slowly mix in oscillator 2 and 3 as desired.
715
716Memories are available via two grey up/down selector buttons, or a three digit
717number can be entered. There are two rows of black buttons where the top row
718is 0 to 4 and the second is 5 to 9. When a memory is selected the LCD display
719will show whether it is is free (FRE) or programmed already (PRG).
720
721
722
723
724 Hammond B3 (dual manual)
725 ------------------------
726
727The author first implemented the Hammond module, then extended it to the B3
728emulation. Users of this are too numerous to mention and the organ is still
729popular. Jimmy Smith, Screaming Jay Hawkins, Kieth Emerson, Doors and
730almost all american gospel blues. Smith was profuse, using the instrument for
731a jazz audience, even using its defects (key noise) to great effect. Emerson
732had two on stage, one to play and another to kick around, even including
733stabbing the keyboard with a knife to force keylock during performances
734(Emerson was also a Moog fan with some of the first live performances). He
735also used the defects of the system to great effect, giving life to the over-
736driven Hammond sound.
737
738The Hammond was historically a mechanical instrument although later cheaper
739models used electronics. The unit had a master motor that rotated at
740the speed of the mains supply. It drove a spindle of cog wheels and next to
741each cog was a pickup. The pickup output went into the matrix of the harmonic
742drawbars. It was originally devised to replace the massive pipe organs in
743churches - Hammond marketed their instruments with claims that they could not be
744differentiated from the mechanical pipe equivalent. He was taken to court by
745the US government for misrepresentation, finally winning his case using a double
746blind competitive test against a pipe organ, in a cathedral, with speakers
747mounted behind the organ pipes and an array of music scholars, students and
748professionals listening. The results spoke for themselves - students would
749have scored better by simply guessing which was which, the professionals
750fared only a little better than that. The age of the Hammond organ had arrived.
751
752The company had a love/hate relationship with the Leslie speaker company - the
753latter making money by selling their rotary speakers along with the organ to
754wide acceptance. The fat hammond 'chorus' was a failed attempt to distance
755themselves from Leslie. That was never achieved due to the acceptance of the
756Leslie, but the chorus did add another unique sound to the already awesome
757instrument. The rotary speaker itself still added an extra something to the
758unique sound that is difficult imagine one without the other. It has a wide
759range of operating modes most of which are included in this emulator.
760
761The chorus emulation is an 8 stage phase shifting filter algorithm with a
762linear rotor between the taps.
763
764Parameterisation of the first B3 window follows the original design:
765
766 Leslie: Rotary speaker on/off
767 Reverb: Reverb on/off
768 VibraChorus: 3 levels of vibrato, 3 of chorus.
769 Bright: Added upper harmonics to waveforms.
770
771Lower and Upper Manual Drawbars: The drawbars are colour coded into white for
772even harmonics and black for odd harmonics. There are two subfrequencies in
773brown. The number given here are the length of organ pipe that would
774correspond to the given desired frequency.
775
776 16 - Lower fundamental
777 5 1/3 - Lower 3rd fundamental
778 8 - Fundamental
779 4 - First even harmonic
780 2 2/3 - First odd harmonic
781 2 - Second even harmonic
782 1 3/5 - Second odd harmonic
783 1 1/3 - Third odd harmonic
784 1 - Third even harmonic
785
786The drawbars are effectively mixed for each note played. The method by which
787the mixing is done is controlled in the options section below. There were
788numerous anomalies shown by the instrument and most of them are emulated.
789
790The Hammond could provide percussives effect the first even and odd harmonics.
791This gave a piano like effect and is emulated with Attack/Decay envelope.
792
793 Perc 4' - Apply percussive to the first even harmonic
794 Perc 2 2/3' - Apply percussive to the first odd harmonic
795 Slow - Adjust rate of decay from about 1/2 second to 4 seconds.
796
797 Soft - Provide a soft attack to each note.
798
799The soft attack is an attempt to reduce the level of undesired key noise. The
800keyboard consisted of a metal bar under each key that made physical contact
801with 9 sprung teeth to tap off the harmonics. The initial contact would generate
802noise that did not really accord to the pipe organ comparison. This was
803reduced by adding a slow start to each key, but the jazz musicians had used
804this defect to great effect, terming it 'key click' and it became a part of
805the Hammond characteristics. Some musicians would even brag about how noisy
806there organ was.
807
808On the left had side are three more controls:
809
810 Volume potentiometer
811
812 Options switch discussed below.
813
814 Rotary Speed: low/high speed Leslie rotation. Shifts between the speeds
815 are suppressed to emulate the spin up and down periods of the leslie motors.
816
817The options section, under control of the options button, has the parameters
818used to control the emulation. These are broken into sections and discussed
819individually.
820
821Leslie:
822
823The Leslie rotary speaker consisted of a large cabinet with a bass speaker and
824a pair of high frequency air horns. Each were mounted on its own rotating table
825and driven around inside the cabinet by motors. A crossover filter was used to
826separate the frequencies driven to either speaker. Each pair was typically
827isolated physically from the other. As the speaker rotated it would generate
828chorus type effects, but far richer in quality. Depending on where the speaker
829was with respect to the listener the sound would also appear to rotate. There
830would be different phasing effects based on signal reflections, different
831filtering effects depending on where the speaker was in respect to the cabinet
832producing differences resonances with respect to the internal baffling.
833
834 Separate:
835 Sync:
836 No Bass:
837 The Leslie had two motors, one for the horns and one for the voice coil
838 speaker. These rotated at different speeds. Some players preferred to
839 have both rotate at the same speed, would remove the second motor and
840 bind the spindles of each speaker table, this had the added effect
841 that both would also spin up at the same rate, not true of the
842 separated motors since each table had a very different rotary moment.
843 The 'No Bass' option does not rotate the voice coil speaker. This was
844 typically done since it would respond only slowly to speed changes,
845 this left just the horns rotating but able to spin up and down faster.
846
847 Brake:
848 Some cabinets had a brake applied to the tables such that when the
849 motor stopped the speakers slowed down faster.
850
851 X-Over:
852 This is the cross over frequency between the voice coil and air horns.
853 Uses a butterworth filter design.
854
855 Inertia:
856 Rate at which speaker rotational speed will respond to changes.
857
858 Overdrive:
859 Amount by which the amplifier is overdriven into distortion.
860
861 H-Depth/Frequency/Phase
862 L-Depth/Frequency/Phase
863 These parameters control the rotary phasing effect. The algorithm used
864 has three differently phased rotations used for filtering, phasing and
865 reverberation of the sound. These parameters are used to control the
866 depth and general phasing of each of them, giving different parameters
867 for the high and low speed rotations. There are no separate parameters
868 for the voice coil or air horns, these parameters are for the two
869 different speeds only, although in 'Separate' mode the two motors will
870 rotate at slightly different speeds.
871
872Chorus
873
874 V1/C1 - Lowest chorus speed
875 V2/C2 - Medium chorus speed
876 V3/C3 - High chorus speed
877
878Percussion:
879
880 Decay Fast/Slow - controls the percussive delay rates.
881 Attack Slow Fast - Controls the per note envelope attack time.
882
883The percussives are emulated as per the original design where there was a
884single envelope for the whole keyboard and not per note. The envelope will only
885restrike for a cleanly pressed note.
886
887Finally there are several parameters affecting the sine wave generation code.
888The Hammond used cogged wheels and coil pickups to generate all the harmonics,
889but the output was not a pure sine wave. This section primarily adjusts the
890waveform generation:
891
892 Preacher:
893 The emulator has two modes of operation, one is to generate the
894 harmonics only for each keyed note and another to generate all of
895 them and tap of those required for whatever keys have been pressed.
896 Both work and have different net results. Firstly, generating each
897 note independently is far more efficient than generating all 90 odd
898 teeth, as only a few are typically required. This does not have totally
899 linked phases between notes and cannot provide for signal damping (see
900 below).
901 The Preacher algorithm generates all harmonics continuously as per the
902 original instrument. It is a better rendition at the expense of large
903 chunks of CPU activity. This is discussed further below.
904
905 Compress:
906 Time compress the sine wave to produce a slightly sharper leading edge.
907
908 Bright:
909 Add additional high frequency harmonics to the sine.
910
911 Click:
912 Level of key click noise
913
914 Reverb:
915 Amount of reverb added by the Leslie
916
917 Damping:
918 If the same harmonic was reused by different pressed keys then its net
919 volume would not be a complete sum, the output gain would decay as the
920 pickups would become overloaded. This would dampen the signal strength.
921 This is only available with the Preacher algorithm.
922
923The two reverse octaves are presets as per the original, however here they can
924just be used to recall the first 23 memories of the current bank. The lower
925manual 12 key is the 'save' key for the current settings and must be double
926clicked. It should be possible to drive these keys via MIDI, not currently
927tested though. The default presets are a mixture of settings, the lower
928manual being typical 'standard' recital settings, the upper manual being a
929mixture of Smith, Argent, Emerson, Winwood and other settings from the well
930known Hammond Leslie FAQ. You can overwrite them. As a slight anomaly, which
931was intentional, loading a memory from the these keys only adjusts the visible
932parameters - the drawbars, leslie, etc. The unseen ones in the options panel
933do not change. When you save a memory with a double click on the lower manual
934last reverse key then in contrast it saves all the parameters. This will not
935change.
936
937The Preacher algorithm supports a diverse set of options for its tonewheel
938emulation. These are configured in the file $BRISTOL/memory/profiles/tonewheel
939and there is only one copy. The file is a text file and will remain that way,
940it is reasonably documented in the file itself. Most settings have two ranges,
941one representing the normal setting and the other the bright setting for when
942the 'bright' button is pressed. The following settings are currently available:
943
944 ToneNormal: each wheel can be given a waveform setting from 0 (square)
945 through to 1.0 (pure sine) to X (sharpening ramp).
946
947 EQNormal: each wheel can be given a gain level across the whole generator.
948
949 DampNormal: each wheel has a damping factor (level robbing/damping/stealing)
950
951 BusNormal: each drawbar can be equalised globally.
952
953
954 ToneBright: each wheel can be given a waveform setting from 0 (square)
955 through to 1.0 (pure sine) to X (sharpening ramp) for the bright button.
956
957 EQBright: each wheel can be given a gain level across the whole generator.
958
959 DampBright: each wheel has a damping factor (level robbing/damping/stealing)
960
961 BusBright: each drawbar can be equalised globally.
962
963
964 stops: default settings for the eight drawbar gain levels.
965
966 The default is 8 linear stages.
967
968 wheel: enables redefining the frequency and phase of any given tonewheel
969
970 The defaults are the slightly non Even Tempered frequencies of the
971 Hammond tonewheels. The tonewheel file redefines the top 6 frequencies
972 that were slightly more out of tune due to the 192-teeth wheels and
973 a different gear ratio.
974
975 crosstalk: between wheels in a compartment and adjacent drawbar busses.
976
977 This is one area that may need extensions for crosstalk in the wiring
978 loom. Currently the level of crosstalk between each of the wheels in
979 the compartment can be individually defined, and drawbar bus crosstalk
980 also.
981
982 compartment: table of the 24 tonewheel compartments and associated wheels.
983
984 resistors: tapering resister definitions for equalisation of gains per
985 wheel by note by drawbar.
986
987 taper: definition of the drawbar taper damping resistor values.
988
989Improvements would come with some other alterations to the sine waveforms and
990some more EQ put into the leslie speaker. The speaker has three speeds, two of
991which are configurable and the third is 'stopped'. Changes between the different
992rates is controlled to emulate inertia.
993
994The net emulation, at least of the preacher algorithm, is reasonable, it is
995distinctively a Hammond sound although it does not have quite as much motor
996or spindle noise. The Bright button gives a somewhat rawer gearbox. It could do
997with a better amplifier emulation for overdrive.
998
999The damping algorithms is not quite correct, it has dependencies on which keys
1000are pressed (upper/lower manual). Options drop shadow is taken from the wrong
1001background bitmap so appears in an inconsistent grey.
1002
1003
1004
1005
1006 Vox Continental
1007 ---------------
1008
1009This emulates the original mark-1 Continental, popular in its time with the
1010Animals on 'House of the Rising Sun', Doors on 'Light my Fire' and most of
1011their other tracks. Manzarek did use Gibson later, and even played with the
1012Hammond on their final album, 'LA Woman' but this organ in part defined
1013the 60's sound and is still used by retro bands for that fact. The Damned
1014used it in an early revival where Captain Sensible punched the keyboard
1015wearing gloves to quite good effect. After that The Specials began the Mod/Ska
1016revival using one. The sharp and strong harmonic content has the ability to
1017cut into a mix and make its presence known.
1018
1019The organ was a british design, eventually sold (to Crumar?) and made into a
1020number of plastic alternatives. Compared to the Hammond this was a fully
1021electronic instrument, no moving parts, and much simpler. It had a very
1022characteristic sound though, sharper and perhaps thinner but was far cheaper
1023than its larger cousin. It used a master oscillator that was divided down to
1024each harmonic for each key (as did the later Hammonds for price reasons). This
1025oscillator division design was used in the first of the polyphonic synthesisers
1026where the divided note was fead through individual envelope generators and
1027a shared or individual filter (Polymoog et al).
1028
1029The Vox is also a drawbar instrument, but far simplified compared to the
1030Hammond. It has 4 harmonic mixes, 16', 8' and 4' drawbars each with eight
1031positions. The fourth gave a mix of 2 2/3, 2, 1 1/3 and 1 foot pipes.
1032An additional two drawbars controlled the overall volume and waveforms, one
1033for the flute or sine waves and another for the reed or ramp waves. The
1034resulting sound could be soft and warm (flute) or sharp and rich (reed).
1035
1036There are two switches on the modulator panel, one for vibrato effect and one
1037for memories and options. Options give access to an chorus effect rather
1038than the simple vibrato, but this actually detracts from the qualities of the
1039sound which are otherwise very true to the original.
1040
1041Vox is a trade name owned by Korg Inc. of Japan, and Continental is one of
1042their registered trademarks. Bristol does not intend to infringe upon these
1043registered names and Korg have their own remarkable range of vintage emulations
1044available. You are directed to their website for further information of true
1045Korg products.
1046
1047
1048
1049
1050 Fender Rhodes
1051 -------------
1052
1053Again not an instrument that requires much introduction. This emulation is
1054the DX-7 voiced synth providing a few electric piano effects. The design is
1055a Mark-1 Stage-73 that the author has, and the emulation is reasonable if not
1056exceptional. The Rhodes has always been widely used, Pink Floyd on 'Money',
1057The Doors on 'Riders on the Storm', Carlos Santana on 'She's not There',
1058everybody else in the 60's.
1059
1060The Rhodes piano generated its sound using a full piano action keyboard where
1061each hammer would hit a 'tine', or metal rod. Next to each rod was a pickup
1062coil as found on a guitar, and these would be linked together into the output.
1063The length of each tine defined its frequency and it was tunable using a tight
1064coiled spring that could be moved along the length of the tine to adjust its
1065moment. The first one was built mostly out of aircraft parts to amuse injured
1066pilots during the second world war. The Rhodes company was eventually sold to
1067Fender and lead to several different versions, the Mark-2 probably being the
1068most widely acclaimed for its slightly warmer sound.
1069
1070There is not much to explain regarding functionality. The emulator has a volume
1071and bass control, and one switch that reveals the memory buttons and algorithm
1072selector.
1073
1074The Rhodes would improve with the addition of small amounts of either reverb
1075or chorus, potentially to be implemented in a future release.
1076
1077The Rhodes Bass was cobbled together largely for a presentation on Bristol.
1078It existed and was used be Manzarek when playing with The Doors in
1079Whiskey-a-GoGo; the owner specified that whilst the music was great they
1080needed somebody playing the bass. Rather than audition for the part Manzarek
1081went out and bought a Rhodes Bass and used it for the next couple of years.
1082
1083
1084
1085
1086 Sequential Circuits Prophet-10
1087 ------------------------------
1088
1089The prophet 10 was the troublesome brother of the Pro-5. It is almost two
1090Prophet-5 in one box, two keyboards and a layering capability. Early models
1091were not big sellers, they were temperamental and liable to be temperature
1092sensitive due to the amount of electronics hidden away inside. The original
1093layering and 'unison' allowed the original to function as two independent
1094synths, a pair of layered synths (both keyboards then played the same sound),
1095as a monophonic synth in 'unison' mode on one keybaord with a second polyphonic
1096unit on the other, or even all 10 voices on a single keyed note for a humongous
109720 oscillator monophonic monster.
1098
1099Phil Collins used this synth, and plenty of others who might not admit to it.
1100
1101The emulator uses the same memories as the Prophet-5, shares the same algorithm,
1102but starts two synths. Each of the two synths can be seen by selecting the U/D
1103(Up/Down) button in the programmer section. Each of the two synthesisers loads
1104one of the Pro-5 memories.
1105
1106There was an added parameter - the Pan or balance of the selected layer, used
1107to build stereo synths. The lower control panel was extended to select the
1108playing modes:
1109
1110 Dual: Two independent keyboards
1111 Poly: Play note from each layer alternatively
1112 Layer: Play each layer simultaneously.
1113
1114In Poly and Layer mode, each keyboard plays the same sounds.
1115
1116 Mods: Select which of the Mod and Freq wheels control which layers.
1117
1118
1119
1120
1121 Sequential Circuits Prophet-5
1122 Sequential Circuits Prophet-52 (the '5' with chorus)
1123 ----------------------------------------------------
1124
1125Sequential circuits released amongst the first truly polyphonic synthesisers
1126where a group of voice circuits (5 in this case) were linked to an onboard
1127computer that gave the same parameters to each voice and drove the notes to
1128each voice from the keyboard. The device had some limited memories to allow
1129for real live stage work. The synth was amazingly flexible regaring the
1130oscillator options and modulation routing, producing some of the fattest
1131sounds around. They also had some of the fattest pricing as well, putting it
1132out of reach of all but the select few, something that maintained its mythical
1133status. David Sylvian of Duran Duran used the synth to wide acclaim in the
1134early 80's as did many of the new wave of bands.
1135
1136The -52 is the same as the -5 with the addition of a chorus as it was easy, it
1137turns the synth stereo for more width to the sound, and others have done it on
1138the Win platform.
1139
1140The design of the Prophet synthesisers follows that of the Mini Moog. It has
1141three oscillators one of them as a dedicated LFO. The second audio oscillator
1142can also function as a second LFO, and can cross modulate oscillator A for FM
1143type effects. The audible oscillators have fixed waveforms with pulse width
1144modulation of the square wave. These are then mixed and sent to the filter with
1145two envelopes, for the filter and amplifier.
1146
1147Modulation bussing is quite rich. There is the wheel modulation which is global,
1148taking the LFO and Noise as a mixed source, and send it under wheel control to
1149any of the oscillator frequency and pulse width, plus the filter cutoff. Poly
1150mods take two sources, the filter envelope and Osc-B output (which are fully
1151polyphonic, or rather, independent per voice), and can route them through to
1152Osc-A frequency and Pulse Width, or through to the filter. To get the filter
1153envelope to actually affect the filter it needs to go through the PolyMod
1154section. Directing the filter envelope to the PW of Osc-A can make wide, breathy
1155scanning effects, and when applied to the frequency can give portamento effects.
1156
1157LFO:
1158
1159 Frequency: 0.1 to 50 Hz
1160 Shape: Ramp/Triangle/Square. All can be selected, none selected should
1161 give a sine wave (*)
1162
1163 (*) Not yet implemented.
1164
1165Wheel Mod:
1166
1167 Mix: LFO/Noise
1168 Dest: Osc-A Freq/Osc-B Freq/Osc-A PW/Osc-B PW/Filter Cutoff
1169
1170Poly Mod: These are affected by key velocity.
1171
1172 Filter Env: Amount of filter envelope applied
1173 Osc-B: Amount of Osc-B applied:
1174 Dest: Osc-A Freq/Osc-A PW/Filter Cutoff
1175
1176Osc-A:
1177
1178 Freq: 32' to 1' in octave steps
1179 Shape: Ramp or Square
1180 Pulse Width: only when Square is active.
1181 Sync: synchronise to Osc-B
1182
1183Osc-B:
1184
1185 Freq: 32' to 1' in octave steps
1186 Fine: +/- 7 semitones
1187 Shape: Ramp/Triangle/Square
1188 Pulse Width: only when Square is active.
1189 LFO: Lowers frequency by 'several' octaves.
1190 KBD: enable/disable keyboard tracking.
1191
1192Mixer:
1193
1194 Gain for Osc-A, Osc-B, Noise
1195
1196Filter:
1197
1198 Cutoff: cuttof frequency
1199 Res: Resonance/Q/Emphasis
1200 Env: amount of PolyMod affecting to cutoff.
1201
1202Envelopes: One each for PolyMod (filter) and amplifier.
1203
1204 Attack
1205 Decay
1206 Sustain
1207 Release
1208
1209Global:
1210
1211 Master Volume
1212 A440 - stable sine wave at A440 Hz for tuning.
1213 Midi: channel up/down
1214 Release: release all notes
1215 Tune: autotune oscillators.
1216 Glide: amount of portamento
1217
1218 Unison: gang all voices to a single 'fat' monophonic synthesiser.
1219
1220This is one of the fatter of the Bristol synths and the design of the mods
1221is impressive (not my design, this is as per sequential circuits spec). Some
1222of the cross modulations are noisy, notably 'Osc-B->Freq Osc-A' for square
1223waves as dest and worse as source.
1224
1225The chorus used by the Prophet-52 is a stereo 'Dimension-D' type effect. The
1226signal is panned from left to right at one rate, and the phasing and depth at
1227a separate rate to generate subtle chorus through to helicopter flanging.
1228
1229Memories are loaded by selecting the 'Bank' button and typing in a two digit
1230bank number followed by load. Once the bank has been selected then 8 memories
1231from the bank can be loaded by pressing another memory select and pressing
1232load. The display will show free memories (FRE) or programmed (PRG).
1233
1234
1235
1236
1237 Oberheim OB-X
1238 -------------
1239
1240Oberheim was the biggest competitor of Sequential Circuits, having their OB
1241range neck and neck with each SC Prophet. The sound is as fat, the OB-X
1242similar to the Prophet-5 as the OB-Xa to the Prophet-10. The synths were widely
1243used in rock music in the late seventies and early 80s. Their early polyphonic
1244synthesisers had multiple independent voices linked to the keyboard and were
1245beast to program as each voice was configured independently, something that
1246prevented much live usage. The OB-X configured all of the voices with the same
1247parameters and had non-volatile memories for instant recall.
1248
1249Priced at $6000 upwards, this beast was also sold in limited quantities and
1250as with its competition gained and maintained a massive reputation for rich,
1251fat sounds. Considering that it only had 21 continuous controllers they were
1252used wisely to build its distinctive and flexible sound.
1253
1254The general design again follows that of the Mini Moog, three oscillators with
1255one dedicated as an LFO the other two audible. Here there is no mixer though,
1256the two audible oscillators feed directly into the filter and then the amplifier.
1257
1258The richness of the sound came from the oscillator options and filter, the
1259latter of which is not done justice in the emulator.
1260
1261Manual:
1262
1263 Volume
1264 Auto: autotune the oscillators
1265 Hold: disable note off events
1266 Reset: fast decay to zero for envelopes, disregards release parameter.
1267 Master Tune: up/down one semitone both oscillators.
1268
1269Control:
1270
1271 Glide: up to 30 seconds
1272 Oscillator 2 detune: Up/down one semitone
1273
1274 Unison: gang all voices to a single 'fat' monophonic synthesiser.
1275
1276Modulation:
1277
1278 LFO: rate of oscillation
1279 Waveform: Sine/Square/Sample&Hold of noise src. Triangle if none selected.
1280
1281 Depth: Amount of LFO going to:
1282 Freq Osc-1
1283 Freq Osc-2
1284 Filter Cutoff
1285
1286 PWM: Amount of LFO going to:
1287 PWM Osc-1
1288 PWM Osc-2
1289
1290Oscillators:
1291
1292 Freq1: 32' to 1' in octave increments.
1293 PulseWidth: Width of pulse wave (*).
1294 Freq2: 16' to 1' in semitone increments.
1295
1296 Saw: sawtooth waveform Osc-1 (**)
1297 Puls: Pulse waveform Osc-1
1298
1299 XMod: Osc-1 FW to Osc-2 (***)
1300 Sync: Osc-2 sync to Osc-1
1301
1302 Saw: sawtooth waveform Osc-2
1303 Puls: Pulse waveform Osc-2
1304
1305 * Although this is a single controller it acts independently on each of the
1306 oscillators - the most recent to have its square wave selected will be
1307 affected by this parameter allowing each oscillator to have a different
1308 pulse width as per the original design.
1309
1310 ** If no waveform is selected then a triangle is generated.
1311
1312 *** The original synth had Osc-2 crossmodifying Osc-1, this is not totally
1313 feasible with the sync options as they are not mutually exclusive here.
1314 Cross modulation is noisy if the source or dest wave is pulse, something
1315 that may be fixed in a future release.
1316
1317Filter:
1318
1319 Freq: cutoff frequency
1320 Resonance: emphasis (*)
1321 Mod: Amount of modulation to filter cutoff (**)
1322
1323 Osc-1: Osc-1 to cutoff at full swing.
1324 KDB: Keyboard tracking of cutoff.
1325
1326 Half/Full: Oscillator 2 to Cutoff at defined levels (***)
1327 Half/Full: Noise to Cutoff at defined levels (***)
1328
1329 * In contrast to the original, this filter can self oscillate.
1330
1331 ** The original had this parameter for the envelope level only, not the
1332 other modifiers. Due to the filter implementation here it affects total
1333 depth of the sum of the mods.
1334
1335 *** These are not mutually exclusive. The 'Half' button gives about 1/4,
1336 the 'Full' button full, and both on gives 1/2. They could be made mutually
1337 exclusive, but the same effect can be generated with a little more flexibility
1338 here.
1339
1340Envelopes: One each for filter and amplifier.
1341
1342 Attack
1343 Decay
1344 Sustain
1345 Release
1346
1347The oscillators appear rather restricted at first sight, but the parametrics
1348allow for a very rich and cutting sound.
1349
1350Improvements would be a fatter filter, but this can be argued of all the
1351Bristol synthesisers as they all share the same design. It will be altered in
1352a future release.
1353
1354The OB-X has its own mod panel (most of the rest share the same frequency and
1355mod controls). Narrow affects the depth of the two controllers, Osc-2 will
1356make frequency only affect Osc-2 rather than both leading to beating, or phasing
1357effects if the oscillators are in sync. Transpose will raise the keyboard by
1358one octave.
1359
1360Memories are quite simple, the first group of 8 buttons is a bank, the second
1361is for 8 memories in that bank. This is rather restricted for a digital synth
1362but is reasonably true to the original. If you want more than 64 memories let
1363me know.
1364
1365
1366
1367
1368 Oberheim OB-Xa
1369 --------------
1370
1371This is almost two OB-X in a single unit. With one keyboard they could provide
1372the same sounds but with added voicing for split/layers/poly options. The OB-Xa
1373did at least work with all 10 voices, had a single keyboard, and is renound for
1374the sounds of van Halen 'Jump' and Stranglers 'Strange Little Girl'. The sound
1375had the capability to cut through a mix to upstage even guitar solo's. Oberheim
1376went on to make the most over the top analogue synths before the cut price
1377alternatives and the age of the DX overcame them.
1378
1379Parameters are much the same as the OB-X as the algorithm shares the same code,
1380with a few changes to the mod routing. The main changes will be in the use of
1381Poly/Split/Layer controllers for splitting the keyboard and layering the sounds
1382of the two integrated synthesisers and the choice of filter algorithm.
1383
1384The voice controls apply to the layer being viewed, selected from the D/U
1385button.
1386
1387Manual:
1388
1389 Volume
1390 Balance
1391 Auto: autotune the oscillators
1392 Hold: disable note off
1393 Reset: fast decay to zero for envelopes, disregards release parameter.
1394 Master Tune: up/down one semitone both oscillators.
1395
1396Control:
1397
1398 Glide: up to 30 seconds
1399 Oscillator 2 detune: Up/down one semitone
1400
1401 Unison: gang all voices to a single 'fat' monophonic synthesiser.
1402
1403Modulation:
1404
1405 LFO: rate of oscillation
1406 Waveform: Sine/Square/Sample&Hold of noise src. Triangle if none selected.
1407
1408 Depth: Amount of LFO going to:
1409 Freq Osc-1
1410 Freq Osc-2
1411 Filter Cutoff
1412
1413 PWM: Amount of LFO going to:
1414 PWM Osc-1
1415 PWM Osc-2
1416 Tremelo
1417
1418Oscillators:
1419
1420 Freq1: 32' to 1' in octave increments.
1421 PulseWidth: Width of pulse wave (*).
1422 Freq2: 16' to 1' in semitone increments.
1423
1424 Saw: sawtooth waveform Osc-1 (**)
1425 Puls: Pulse waveform Osc-1
1426
1427 Env: Application of Filter env to frequency
1428 Sync: Osc-2 sync to Osc-1
1429
1430 Saw: sawtooth waveform Osc-2
1431 Puls: Pulse waveform Osc-2
1432
1433 * Although this is a single controller it acts independently on each of the
1434 oscillators - the most recent to have its square wave selected will be
1435 affected by this parameter allowing each oscillator to have a different
1436 pulse width, as per the original design.
1437
1438 ** If no waveform is selected then a triangle is generated.
1439
1440Filter:
1441
1442 Freq: cutoff frequency
1443 Resonance: emphasis (*)
1444 Mod: Amount of modulation to filter cutoff (**)
1445
1446 Osc-1: Osc-1 to cutoff at full swing.
1447 KDB: Keyboard tracking of cutoff.
1448
1449 Half/Full: Oscillator 2 to Cutoff at defined levels (***)
1450
1451 Noise: to Cutoff at defined levels
1452 4 Pole: Select 2 pole or 4 pole filter
1453
1454 * In contrast to the original, this filter will self oscillate.
1455
1456 ** The original had this parameter for the envelope level only, not the
1457 other modifiers. Due to the filter implementation here it affects total
1458 depth of the sum of the mods.
1459
1460 *** These are not mutually exclusive. The 'Half' button gives about 1/4,
1461 the 'Full' button full, and both on gives 1/2. They could be made mutually
1462 exclusive, but the same effect can be generated with a little more flexibility
1463 here.
1464
1465Envelopes: One each for filter and amplifier.
1466
1467 Attack
1468 Decay
1469 Sustain
1470 Release
1471
1472Mode selection:
1473
1474 Poly: play one key from each layer alternatively for 10 voices
1475 Split: Split the keyboard. The next keypress specifies split point
1476 Layer: Layer each voice on top each other.
1477
1478 D/U: Select upper and lower layers for editing.
1479
1480Modifier Panel:
1481
1482 Rate: Second LFO frequency or Arpeggiator rate (*)
1483 Depth: Second LFO gain
1484 Low: Modifiers will affect the lower layer
1485 Up: Modifiers will affect the upper layer
1486 Multi: Each voice will implement its own LFO
1487 Copy: Copy lower layer to upper layer
1488
1489 Mod 01: Modify Osc-1 in given layer
1490 Mod 02: Modify Osc-2 in given layer
1491 PW: Modify Pulse Width
1492 AMT: Amount (ie, depth) of mods and freq wheels
1493
1494 Transpose: Up or Down one octave.
1495
1496The Arpeggiator code integrated into release 0.20.4 has three main parts, the
1497arpeggiator itself, the arpeggiating sequencer and the chording. All are
1498configured from the left of the main panel.
1499
1500The arpeggiator is governed by the rate control that governs how the code
1501steps through the available keys, an octave selector for 1, 2 or 3 octaves
1502of arpeggiation, and finally the Up/Down/Up+Down keys - the last ones start
1503the arpeggiator. Arpeggiation will only affect the lower layer.
1504
1505When it has been started you press keys on the keyboard (master controller
1506or GUI) and the code will step through each note and octaves of each note
1507in the order they were pressed and according to the direction buttons. The
1508key settings are currently reset when you change the direction and you will
1509have to press the notes again.
1510
1511The sequencer is a modification of the code. Select the Seq button and then
1512a direction. The GUI will program the engine with a series of notes (that can
1513be redefined) and the GUI will sequence them, also only into the lower layer.
1514The sequence will only start when you press a key on the keyboard, this is
1515the starting point for the sequence. You can press multiple notes to have
1516them sequence in unison. Once started you can tweak parameters to control
1517the sound and memory 88 when loaded has the filter envelope closed down, a
1518bit of glide and some heavy mods to give you a starting point for some serious
1519fun.
1520
1521To reprogram the sequence steps you should stop the sequencer, press the PRG
1522button, then the Sequence button: enter the notes you want to use one by one
1523on the keyboard. When finished press the sequence button again, it goes out.
1524Now enable it again - select Seq and a direction and press a note. Press two
1525notes.
1526
1527When you save the memory the OBXa will also save the sequence however there
1528is only one sequence memory - that can be changed if you want to have a sequence
1529memory per voice memory (implemented in 0.20.4).
1530
1531The chord memory is similar to the Unison mode except that Unison plays all
1532voices with the same note. Chording will assign one voice to each notes in
1533the chord for a richer sound. To enable Chording press the 'Hold' button. This
1534is not the same as the original since it used the hold button as a sustain
1535option however that does not function well with a Gui and so it was reused.
1536
1537To reprogram the Chord memory do the following: press the PRG button then the
1538Hold button. You can then press the keys, up to 8, that you want in the chord,
1539and finally hit the Hold button again. The default chord is just two notes,
1540the one you press plus its octave higher. This results in multiple voices
1541per keypress (a total of 3 in Layered mode) and with suitable detune will
1542give a very rich sound.
1543
1544There is only one arpeggiator saved for all the memories, not one per memory
1545as with some of the other implementations. Mail me if you want that changed.
1546
1547
1548
1549The oscillators appear rather restricted at first sight, but the parametrics
1550allow for a very rich and cutting sound.
1551
1552The Copy function on the Mod Panel is to make Poly programming easier - generate the desired sound and then copy the complete parameter set for poly operation.
1553It can also be used more subtly, as the copy operation does not affect balance
1554or detune, so sounds can be copied and immediately panned slightly out of tune to generate natural width in a patch. This is not per the original instrument
1555that had an arpeggiator on the mod panel.
1556
1557The Arpeggiator was first integrated into the OBXa in release 0.20.4 but not
1558widely tested.
1559
1560
1561
1562
1563 KORG MONOPOLY
1564 -------------
1565
1566A synth suite would not be complete without some example of a Korg instrument,
1567the company was also pivotal in the early synthesiser developments. This is
1568an implementation of their early attempts at polyphonic synthesis, it was
1569either this one or the Poly-6 (which may be implemented later). Other choices
1570would have been the MS series, MS-20, but there are other synth packages that
1571do a better job of emulating the patching flexibility of that synth - Bristol
1572is more for fixed configurations.
1573
1574As with many of the Korg synths (the 800 worked similarly) this is not really
1575true polyphony, and it is the quirks that make it interesting. The synth had
1576four audio oscillators, each independently configurable but which are bussed
1577into a common filter and envelope pair - these are not per voice but rather
1578per instrument. The unit had different operating modes such that the four
1579oscillators can be driven together for a phat synth, independently for a form
1580of polyphony where each is allocated to a different keypress, and a shared
1581mode where they are assigned in groups depending on the number of keys pressed.
1582For example, if only 2 notes are held then each key is sounded on two different
1583oscillators, one key is sounded on all 4 oscillators, and 3 or more have one
1584each. In addition there are two LFOs for modulation and a basic effects option
1585for beefing up the sounds. To be honest to the original synth, this emulation
1586will only request 1 voice from the engine. Korg is one of the few original
1587manufacturers to have survived the transition to digital synthesis and are
1588still popular.
1589
1590One thing that is immediately visible with this synth is that there are a lot
1591of controllers since each oscillator is configured independently. This is in
1592contrast to the true polyphonic synths where one set of controls are given to
1593configure all the oscillators/filters/envelopes. The synth stages do follow the
1594typical synth design, there are modulation controllers and an FX section
1595feeding into the oscillators and filter. The effects section is a set of
1596controllers that can be configured and then enabled/disabled with a button
1597press. The overall layout is rather kludgy, with some controllers that are
1598typically grouped being dispersed over the control panel.
1599
1600Control:
1601
1602 Volume
1603
1604 Arpeg:
1605 Whether arpegiator steps up, down, or down then up. This works in
1606 conjunction with the 'Hold' mode described later.
1607
1608 Glide: glissando note to note. Does not operate in all modes
1609
1610 Octave: Up/Normal/Down one octave transpose of keyboard
1611
1612 Tune: Global tuning of all oscillators +/- 50 cents (*)
1613 Detune: Overall detuning of all oscillators +/- 50 cents (*)
1614
1615 * There is an abundance of 'Tune' controllers. Global Tuning affects all
1616 the oscillators together, then oscillators 2, 3 and 4 have an independent
1617 tune controller, and finally there is 'Detune'. The target was to tune all
1618 the oscillators to Osc-1 using the independent Tune for each, and then use
1619 the global Tune here to have the synth tuned to other instruments. The
1620 Detune control can then be applied to introduce some beating between the
1621 oscillators to fatten the sound without necessarily losing overall tune of
1622 the instrument.
1623
1624Modulation wheels:
1625
1626 Bend:
1627 Intensity: Depth of modulation
1628 Destination:
1629 VCF - Filter cutoff
1630 Pitch - Frequency of all oscillators
1631 VCO - Frequency of selected oscillators (FX selection below).
1632
1633 MG1: Mod Group 1 (LFO)
1634 Intensity: Depth of modulation
1635 Destination:
1636 VCF - Filter cutoff
1637 Pitch - Frequency of all oscillators
1638 VCO - Frequency of selected oscillators (FX selection below).
1639
1640LFO:
1641
1642 MG-1:
1643 Frequency
1644 Waveform - Tri, +ve ramp, -ve ramp, square.
1645
1646 MG-2:
1647 Frequency (Triangle wave only).
1648
1649Pulse Width Control:
1650
1651 Pulse Width Modulation:
1652 Source - Env/MG-1/MG-2
1653 Depth
1654
1655 Pule Width
1656 Width control
1657
1658 These controllers affect Osc-1 though 4 with they are selected for either
1659 square of pulse waveforms.
1660
1661Mode:
1662
1663 The Mono/Poly had 3 operating modes, plus a 'Hold' option that affects
1664 each mode:
1665
1666 Mono: All oscillators sound same key in unison
1667 Poly: Each oscillator is assigned independent key - 4 note poly.
1668 Share: Dynamic assignment:
1669 1 key - 4 oscillators = Mono mode
1670 2 key - 2 oscillators per key
1671 3/4 - 1 oscillator per key = Poly mode
1672
1673 The Hold function operates in 3 different modes:
1674
1675 Mono: First 4 keypresses are memorised, further notes are then chorded
1676 together monophonically.
1677 Poly:
1678 Notes are argeggiated in sequence, new note presses are appended
1679 to the chain. Arpeggiation is up, down or up/down.
1680 Share:
1681 First 4 notes are memorised and are then argeggiated in sequence,
1682 new note presses will transpose the arpeggiation. Stepping is up,
1683 down or up/down.
1684
1685 There are several controllers that affect arpeggation:
1686
1687 Arpeg - direction of stepping
1688 MG-2 - Frequency of steps from about 10 seconds down to 50 bps.
1689 Trigger - Multiple will trigger envelopes on each step.
1690
1691Effects:
1692
1693 There are three main effects, or perhaps rather modulations, that are
1694 controlled in this section. These are vibrato, crossmodulated frequency
1695 and oscillator synchronisation. The application of each mod is configured
1696 with the controllers and then all of them can be enabled/disabled with
1697 the 'Effects' button. This allows for big differences in sound to be
1698 applied quickly and simply as a typical effect would be. Since these mods
1699 apply between oscillators it was envisaged they would be applied in Mono
1700 mode to further fatten the sound, and the Mono mode is actually enabled when
1701 the Effects key is selected (as per the original instrument). The Mode can
1702 be changed afterwards for Effects/Poly for example, and they work with the
1703 arpeggiation function.
1704
1705 X-Mod: frequency crossmodulation between oscillators
1706 Freq: frequency modulation by MG-1 (vibrato) or Envlope (sweep)
1707
1708 Mode:
1709 Syn: Oscillators are synchronised
1710 X-M: Oscillators are crossmodulated
1711 S-X: Oscillators are crossmodulated and synchronised
1712
1713 SNG:
1714 Single mode: synth had a master oscillator (1) and three slaves (2/3/4)
1715 DBL:
1716 Double mode: synth had two master (1/3) and two slaves (2/4)
1717
1718 The overall FX routing depends on the SNG/DBL mode and the selection of
1719 Effects enabled or not according to the table below. This table affects
1720 the FX routing and the modulation wheels discussed in the LFO section above:
1721
1722 --------------------------------------------------
1723 | FX OFF | FX ON |
1724 | |----------------------------------
1725 | | Single | Double |
1726 ---------------+--------------+-----------------+---------------|
1727 | VCO-1/Slave | VCO-1 | VCO 2/3/4 | VCO 2/4 |
1728 | | | | |
1729 | Pitch | VCO 1-4 | VCO 1-4 | VCO 1-4 |
1730 | | | | |
1731 | VCF | VCF | VCF | VCF |
1732 -----------------------------------------------------------------
1733
1734 So, glad that is clear. Application of the modulation wheels to Pitch and
1735 VCF is invariable when they are selected. In contrast, VCO/Slave will have
1736 different destinations depending on the Effects, ie, when effects are on
1737 the modwheels will affect different 'slave' oscillators.
1738
1739
1740Oscillators:
1741
1742 Each oscillator had the following controllers:
1743
1744 Tune (*)
1745 Waveform: Triangle, ramp, pulse, square (**)
1746 Octave: Transpose 16' to 2'
1747 Level: output gain/mix of oscillators.
1748
1749 * Osc-1 tuning is global
1750 ** width of pulse and square wave is governed by PW controller. The
1751 modulation of the pulse waveform is then also controlled by PWM.
1752
1753Noise:
1754
1755 Level: white noise output gain, mixed with oscillators into filter.
1756
1757VCF:
1758
1759 Freq:
1760 Cutoff frequency
1761
1762 Res:
1763 Resonance/emphasis.
1764
1765 Env:
1766 Amount of contour applied to cutoff
1767
1768 KBD:
1769 Amount of key tracking applied.
1770
1771ADSR: Two: filter/PWM/FX, amplifier
1772
1773 Attack
1774 Decay
1775 Sustain
1776 Release
1777
1778 Trigger:
1779 Single: Trigger once until last key release
1780 Multi: Trigger for each key or arpeggiator step.
1781
1782 Damp:
1783 Off: Notes are held in Poly/Share mode until last key is released.
1784 On: Oscillators are released as keys are released.
1785
1786This is more a synth to play with than describe. It never managed to be a true
1787blue synth perhaps largely due to its unusual design: the quasi-poly mode was
1788never widely accepted, and the effects routing is very strange. This does make
1789it a synth to be tweaked though.
1790
1791Some of the mod routings do not conform to the original specification for the
1792different Slave modes. This is the first and probably the only bristol synth that
1793will have an inbuilt arpeggiator. The feature was possible here due to the mono
1794synth specification, and whilst it could be built into the MIDI library for
1795general use it is left up to the MIDI sequencers (that largely came along to
1796replace the 1980s arpeggiators anyway) that are generally availlable on Linux.
1797[Other instruments emulated by bristol that also included arpeggiation but do
1798not have in the emulation were the Juno-6, Prophet-10, Oberheim OB-Xa, Poly6].
1799
1800As of May 06 this synth was in its final stages of development. There are a few
1801issues with Tune and Detune that need to be fixed, and some of the poly key
1802assignment may be wrong.
1803
1804
1805
1806
1807 KORG POLY 6
1808 -----------
1809
1810Korg in no way endorses this emulation of their classic synthesiser and have
1811their own emulation product that gives the features offered here. Korg,
1812Mono/Poly, Poly-6, MS-20, Vox and Continental are all registered names or
1813trademarks of Korg Inc of Japan.
1814
1815Quite a few liberties were taken with this synth. There were extremely few
1816differences between the original and the Roland Juno 6, they both had one osc
1817with PWM and a suboscillator, one filter and envelope, a chorus effect, and
1818inevitably both competed for the same market space for their given price. To
1819differentiate this algorithm some alterations were made. There are two separate
1820envelopes rather than just one, but the option to have a gated amplifier is
1821still there. In addition glide and noise were added, both of which were not in
1822the original instrument. With respect to the original instrument this was
1823perhaps not a wise move, but there seemed little point in making another Juno
1824with a different layout. The net results is that the two synths do sound quite
1825different. The emulation does not have an arpeggiator.
1826
1827 Volume: Master volume of the instrument
1828
1829 Glide: length of portamento
1830
1831 Tune: Master tuning of instrument
1832
1833 Bend: Amount of pitch wheel that is applied to the oscillators frequency.
1834
1835
1836 VCO section:
1837
1838 Octave: What octave the instrument's keyboard is in.
1839
1840 Wave: Waveform selection: Triangle, Saw, Pulse and Pulsewidth
1841
1842 PW PWM: Amount of Pulsewidth (when Pulse is selected) and Pulsewidth
1843 Modulation (When Pulsewidth is selected).
1844
1845 Freq: Frequency of PW/PWM
1846
1847 OFF/SUB1/SUB2; Adds a square sub-oscillator either off, 1 or 2 octaves
1848 down from a note.
1849
1850 MG (Modulation Group):
1851
1852 Freq: Frequency of LFO
1853
1854 Delay: Amount of time before the LFO affects the destination when a key
1855 is pressed.
1856 Level: How strongly the LFO affects the destination
1857
1858 VCO/VCF/VCA: Destinations that the LFO can go to:
1859
1860 VCO: The Voltage Controlled Oscillator:
1861 Affects oscillator pitch, producing vibrato
1862
1863 VCF: The Voltage Controlled Filter:
1864 Affects Filter, producing a wah effect
1865
1866 VCA: The Voltage Controlled Amplifier:
1867 Affects the Amplifier, producing tremolo
1868
1869 VCF section:
1870
1871 Freq: Cut off frequency of the filter
1872
1873 Res: Resonance of the filter
1874
1875 Env: By how much the filter is affected by the envelope.
1876
1877 Kbd: How much Keyboard tracking is applied to the envelope. note:
1878
1879 A low setting doesn't allow the filter to open, making the notes
1880 seem darker the further you go up the keyboard.
1881
1882 Hold: prevent key off events
1883
1884 Mono Mode: Gang all voices to a single 'fat' monophonic synthesiser.
1885
1886 Poly: One voice per note.
1887
1888 Envelope Section:
1889
1890 Top:
1891
1892 Filter envelope:
1893
1894 Attack: Amount of time it takes the filter to fully open.
1895 A high value can produce a 'sweeping filter' effect.
1896 Decay: Amount of time it takes for the filter to close to
1897 the sustain level
1898 Sustain: Amount of filter that is sustained when a key is held
1899
1900 Release: Amount of time it takes for the filter envelope to stop
1901 affecting the filter. Combining a low filter release with a
1902 high amplitude release time can cause an interesting effect.
1903
1904 Bottom:
1905
1906 Amplitude envelope:
1907
1908 Attack: Amount of time it takes for the signal to reach its peak.
1909
1910 Decay: Amount of time it takes for the signal to drop to the
1911 sustain level
1912 Sustain: How quickly the sound decays to silence.
1913
1914 Release: How long it takes the sound to decay to silence after
1915 releasing a key.
1916
1917 VCA:
1918
1919 Env: When on, this causes the Amplitude envelope to affect the sound.
1920 I.E, If you have a long attack time, you get a long attack time.
1921 Gate: When on, this causes the Amplitude envelope only (not the filter
1922 envelope) to be be bypassed.
1923 Gain: Gain of signal.
1924
1925 Effects Section:
1926
1927 0: No effects
1928 1: Soft Chorus
1929 2: Phaser
1930 3: Ensemble
1931
1932 Intensity: How much the effects affect the output.
1933
1934There are some mildly anomolous effects possible from the MG section, especially
1935with the VCA. The MG and the env are summed into the VCA which means if the env
1936decays to zero then the LFO may end up pumping the volume, something that may
1937be unexpected. Similarly, if the LFO is pumping and the voice finally stops its
1938cycle then the closing gate may cause a pop on the MG signal. These can be
1939resolved however the current behavious is probably close to the original.
1940
1941Bristol thanks Andrew Coughlan for patches, bug reports, this manual page and
1942diverse suggestions to help improve the application.
1943
1944Korg in no way endorses this emulation of their classic synthesiser and have
1945their own emulation product that gives the features offered here. Korg,
1946Mono/Poly, Poly-6, MS-20, Vox and Continental are all registered names or
1947trademarks of Korg Inc of Japan.
1948
1949
1950
1951
1952 ARP AXXE
1953 --------
1954
1955TBD
1956
1957At the risk of getting flamed, this is potentially the ugliest synth ever made,
1958although the competition is strong. It was implemented as a build up to the far
1959more useful ARP 2600 to understand the ARP components and their implementation.
1960
1961The implementation is a giveaway written during a week long business trip to
1962Athens to keep me busy in the hotel. Its design lead on to the Odyssey and that
1963was the step towards the final big brother, the ARP 2600.
1964
1965
1966
1967
1968 ARP ODYSSEY
1969 -----------
1970
1971Ring modulation is correct here, it is a multiplier. This deviates from the
1972original instrument that used an XOR function on the pulsewave outputs of the
1973two oscillators. The implementation has two models, Mark-I and Mark-II. These
1974implement different filters as per the original. Although their characteristics
1975are different it is not suggested they are a particularly close emulation of
1976the original.
1977
1978TBD
1979
1980
1981
1982
1983 Memory Moog
1984 -----------
1985
1986TBD.
1987
1988This is actually a lot warmer than the Mini emulator, largely due to being
1989later code. The mini should be revisited but I am saving that pleasure for when
1990some more filters are available. [This was done during the 0.20 stream using the
1991Houvilainen filters and bandwidth limited oscillators to produce a far richer
1992sound. Also incorporate a number of fixes to the emulation stages.].
1993
1994
1995
1996
1997 ARP 2600
1998 --------
1999
2000This synth will probably never get a writeup, it is kind of beyond the scope of
2001this document. There are some discrepancies with the original:
2002
2003The filters do not self oscillate, they require an input signal. The output
2004stage is global to all voices so cannot be patched back into the signal path.
2005The original did not have a chorus, only a spring reverb. The input stage has
2006not been tested for either signal nor envelope following code. The voltage
2007manipulators were not in the first bristol upload with this emulation (-60),
2008but a future release will include mixing inverters, a lag processor, and
2009possibly also a Hz->V extractor. The unit has an extra LFO where the original
2010had just a clock trigger circuit, it produces a TRI wave, can be used to
2011trigger the AR envelope and be used for modulation. The electroswitch is
2012unidirectional, two inputs switchable to one output. The sample and hold
2013circuit cannot accept an external clock. The Keyboard inputs to the VCO cannot
2014accept and alternative signal other than the MIDI note with tracking of this
2015note either enabled or disabled.
2016
2017The rest works, ie, all the VCO/VCF/VCA/ENV/AMP and any of the 30 or so outputs
2018can be repatched into any of the 50 or so inputs. Patches cause no overhead in
2019the engine as it uses default buffering when not repatched, so feel free to put
2020in as many cables as you can fit. Patches in the GUI still demand a lot of CPU
2021cycles. Release -77 improved this about 5-fold and further improvements are in
2022the pipeline: the 0.10 stream implemented color caching and XImage graphics
2023interface which massively improved GUI performance.
2024
2025
2026
2027
2028 REALISTIC MG-1 CONCERTMATE
2029 --------------------------
2030
2031This is a pimpy little synth. It was sold through the Realistic electronics
2032chain, also known as Radio Shack (and as Tandy, in the UK at least). It was
2033relatively cheap but had a design from Moog Music (from after Robert Moog
2034had left?) including the patented ladder filter. It consisted of a monophonic
2035synth, dual oscillator, lfo, noise, filter, env, and a ring modulator. On top
2036of that there was an organ circuit to give 'polyphony'. It was not really
2037polyphonic although different descriptions will tell you it had 10 voices.
2038These write-ups are by people who probably only had 10 fingers, the truth is
2039that the organ circuit was as per any other - it had a master oscillator at
2040about 2MHz and this was divided using binary counters to deliver a frequency
2041for every note. The output of the 'poly' section was lamentable at best, it is
2042a fairly pure square wave passed through the filter and contour. This is fully
2043emulated although in addition to the contour bristol implements a per note
2044envelope just to groom the note - this prevents ticks when new keys are pressed
2045with the mono envelope fully open. There is no access to this env, it just has
2046fast attack and decay times to smooth the signal and is preconfigured by the
2047user interface on startup.
2048
2049The mono section is reasonably fun, the oscillators can be synchronised and
2050there is a ring modulator so the range of sounds is quite wide. The emulator
2051uses a chaimberlain filter so is not as warm as the Moog ladder filters.
2052
2053The list of people who used this is really quite amazing. The promotion for
2054the product had Elton John holding one up in the air, although seeing as he
2055probably already had every other synth known to man, holding it up in the
2056air is likely to be all he ever did with it. Who knows how much they had to
2057pay him to do it - the photo was nice though, from the days when Elton was
2058still bald and wearing ridiculously oversized specs.
2059
2060Tuning:
2061
2062 One control each for the poly oscillator and mono oscillators
2063
2064Glide:
2065
2066 Only affects the monophonic oscillators.
2067
2068Modulation:
2069
2070 One LFO with rate and waveshape selection
2071 produces tri, square and S/H signals.
2072 can trigger the envelope
2073 One noise source.
2074 The modulation can be directed to:
2075 Oscillators for vibrato
2076 Filter for wah-wah effects
2077
2078Oscillator-1:
2079
2080 Tri or square wave
2081 Octave from -2 to 0 transposition
2082 Sync selector (synchronises Osc-2 to Osc-1)
2083
2084Oscillator-2:
2085
2086 Tri or pulse wave
2087 Detune. This interoperates with the sync setting to alter harmonics
2088 Octave from -1 to +1 transposition
2089
2090Contour: This is not an ADSR, rather an AR envelope
2091
2092 Sustain: AR or ASR envelope selector.
2093 Tracking: controls mono oscillators
2094 Envelope control
2095 Key tracking (gate, no env)
2096 Continuous (always on)
2097 Rise (attack time)
2098 Fall (release time)
2099
2100Filter:
2101
2102 Cutoff frequency
2103 Emphasis
2104 Contour depth
2105 Keyboard tracking off, 1/2, full.
2106
2107Mixer: Levels for
2108 Mono Osc-1
2109 Mono Osc-2
2110 Noise
2111 RingMod of the mono oscillators (called 'bell').
2112 Poly Osc level.
2113
2114Master Volume control.
2115
2116One extra button was added to save the current settings. For the rest the
2117controls reflect the simplicity of the original. The implementation is a single
2118synth, however due to the engine architecture having a pre-operational routine,
2119a post-operational routine and an operate(polyphonic emulator) the emulation
2120executes the mono synth in the pre- and post- ops to be mono, these are called
2121just once per cycle. The poly synth is executed in the operate() code so is
2122polyphonic. This leads to one minor deviation from the original routing in
2123that if you select continuous tone controls then you will also hear one note
2124from the poly section. This is a minor issue as the poly oscillator can be
2125zeroed out in the mixer.
2126
2127It is noted here that this emulation is just a freebie, the interface is kept
2128simple with no midi channel selection (start it with the -channel option and
2129it stays there) and no real memories (start it with the -load option and it
2130will stay on that memory location). There is an extra button on the front
2131panel (a mod?) and pressing it will save the current settings for next time
2132it is started. I could have done more, and will if people are interested, but
2133I built it since the current developments were a granular synth and it was
2134hard work getting my head around the grain/wave manipulations, so to give
2135myself a rest I put this together one weekend. The Rhodesbass and ARP AXXE
2136were done for similar reasons. I considered adding another mod button, to make
2137the mono section also truly polyphonic but that kind of detracts from the
2138original. Perhaps I should put together a Polymoog sometime that did kind of
2139work like that anyway.
2140
2141This was perhaps a strange choice, however I like the way it highlights the
2142difference between monophonic, polyphonic and 'neopolyphonic' synthesised
2143organs (such as the polymoog). Its a fun synth as well, few people are likely
2144to every bother buying one as they cost more now than when they were produced
2145due to being collectable: for the few hundred dollars they would set you back
2146on eBay you can get a respectable polyphonic unit.
2147So here is an emulator, for free, for those who want to see how they worked.
2148
2149
2150
2151
2152 Vox Continental 300
2153 -------------------
2154
2155There is an additional emulator for the later Mark-II, Super, 300 or whatever
2156model you want to call it. This is probably closest to the 300. It was a
2157dual manual organ, the lower manual is a Continental and the upper manual had
2158a different drawbar configuration, using 8', 4' and 2', another two compound
2159drawbars that represented 5-1/3'+1-3/5', and 2-2/3'+2'+1' respectively. This
2160gave upper manual a wider tonic range, plus it had the ability to apply some
2161percussive controls to two of the drawbars. Now, depending on model, some of
2162these values could be different and bristol does not emulate all the different
2163combinations, it uses the harmonics described above and applies percussive to
2164the 2' and 5-1/3' harmonics (which is arguably incorrect however it gives
2165a wider combination of percussive harmonics).
2166
2167The percussive has 4 controls, these are selectors for the harmonics that will
2168be driven through the percussive decay (and then no longer respond to the
2169drawbars), a decay rate called 'L' which acts as a Longer decay when selected,
2170and a volume selector called 'S' which stands for Soft. The variables are
2171adjustable in the mods section. The mods panel is intended to be hidden as
2172they are just variable parameters. On the original units these were PCB mounted
2173pots that were not generally accessible either. The panel is visible when you
2174turn the power control off, not that I suppress the keyboard or anything when
2175the power is off, but it gave me something useful do to with this button. The
2176transparency layer is fixed here and is used to apply some drop shadow and a
2177few beer spills on the cover.
2178
2179There is an additional Bass section for those who bought the optional Bass
2180pedals (my old one had them). The emulation allow the selection of Flute and
2181Reed strengths, and to select 8' or 8'/16' harmonics. The 'Sustain' control
2182does not currently operate (0.10.9) but that can be fixed if people request
2183the feature.
2184
2185The lower manual responds to the MIDI channel on which the emulation was
2186started. The upper manual responds to notes greater than MIDI key 48 on the
2187next channel up. The Bass section also responds to this second channel on keys
2188lower than #48. Once started you cannot change the midi channel - use the
2189'-channel' option at startup to select the one you want. The actual available
2190max is 15 and that is enforced.
2191
2192The emulation only contains 6 available presets and a 'Save' button that you
2193need to double click to overwrite any preset. The emulation actually uses
2194banks, so if you started it with '-load 23' it would start up by selecting
2195bank 20, and load memory #3 from that bank. Any saved memories are also then
2196written back to bank 20, still with just 6 memories accessible 20-25. You can
2197access more via MIDI bank select and program change operations if suitably
2198linked up.
2199
2200Vox is a trade name owned by Korg Inc. of Japan, and Continental is one of
2201their registered trademarks. Bristol does not intend to infringe upon these
2202registered names and Korg have their own remarkable range of vintage emulations
2203available. You are directed to their website for further information of true
2204Korg products.
2205
2206
2207
2208
2209 Roland Jupiter 8
2210 ----------------
2211
2212This emulator is anticipated in 0.20.4.
2213
2214The Jupiter synthesizers were the bigger brothers of the Juno series: their
2215capabilities, sounds and prices were all considerably larger. This is the
2216larger of the series, the others being the -4 and -6. The -6 and the rack
2217mounted MKS-80 both came out after the Jupiter-8 and had somewhat more flexible
2218features. Several of these have been incorporated into the emulation and that
2219is documented below.
2220
2221A quick rundown of the synth and emulation:
2222
2223The synth runs as two layers, each of which is an independent emulator running
2224the same algorithm, both layers are controlled from the single GUI. The layers
2225are started with a set of voices, effectively 4+4 per default however bristol
2226plays with those numbers to give the split/layer at 4 voices each and the 'All'
2227configuration with 8 voices - it juggles them around depending on the Poly
2228mode you select. You can request a different number of voices and the emulator
2229will effectively allocate half the number to each layer. If you request 32
2230voices you will end up with 4+4 though since 32 is interpreted as the default.
2231
2232The Poly section is used to select between Dual layers, Split keyboard and the
22338voice 'All' mode. You can redefine the split point with a double click on the
2234'Split' button and then pressing a key. If you have linked the GUI up to the
2235MIDI you should be able to press a key on your master keyboard rather than on
2236the GUI.
2237
2238After that you can select the layer as upper or lower to review the parameter
2239settings of each layer: they are as follows:
2240
2241LFO:
2242 Frequency
2243 Delay
2244 Waveform (tri, saw, square, s&h)
2245
2246VCO Mods:
2247 LFO and ENV-1
2248 Destination to modulate frequency of DCO1, DCO2 or both.
2249
2250PWM:
2251 PW
2252 PWM
2253 Modified by Env-1 or LFO
2254
2255DCO-1:
2256 Crossmod (FM) from DCO2 to DCO1
2257 Modified by Env-1
2258
2259 Octave range 16' to 2' (all mixable)
2260 Waveform: Tri, saw, pulse, square (all mixable)
2261
2262DCO-2:
2263 Sync (1->2 or 2->1 or off)
2264 Range: 32' to 2' (all mixable)
2265 Tuning
2266 Waveform: tri, saw, pulse, noise (all mixable)
2267
2268Mix:
2269 Osc 1 and Osc 2
2270
2271HPF:
2272 High pass filter of signal
2273
2274Filter:
2275 Cutoff
2276 Emphasis
2277 LPF/BPF/HPF
2278 Env modulation
2279 Source from Env-1 or Env-2
2280 LFO mod amount
2281 Keyboard tracking amount
2282
2283VCA:
2284 Env-2 modulation
2285 LFO modulation
2286
2287ADSR-1:
2288 A/D/S/R
2289 Keyboard tracking amount
2290 Invert
2291
2292ADSR-2:
2293 A/D/S/R
2294 Keyboard tracking amount
2295
2296Pan:
2297 Stereo panning of layer
2298
2299All of the above 40 or so parameters are part of the layer emulation and are
2300separately configurable.
2301
2302The keyboard can operate in several different modes which are selectable from
2303the Poly and Keyboard mode sections. The first main one is Dual, Split and All.
2304Dual configure the two synth layers to be placed on top of each other. Split
2305configures them to be next to each other and by double clicking the split
2306button you can then enter a new split point by pressing a key. The All setting
2307gives you a single layer with all 8 voices active. These settings are for the
2308whole synth.
2309
2310The Poly section provides different playing modes for each layer independently.
2311There are 3 settings: Solo give the layer access to a single voice for playing
2312lead solos. Unison give the layer however many voices it is allowed (8 if in
2313the All mode, 4 otherwise) and stacks them all on top of each other. This is
2314similar to Solo but with multiple voices layered onto each other. Unison is
2315good for fat lead sounds, Solo better for mono bass lines where Unison might
2316have produced unwanted low frequency signal phasing. The third option is Poly
2317mode 1 where the synth allocates a single voice to each key you press. The
2318original also had Poly mode 2 which was not available at the first bristol
2319release - this mode would apply as many notes as available to the keys you
2320pressed: 1 key = 8 voices as in Unison, with 2 keys pressed each would get 4
2321voices each, 4 keys pressed would get 2 voices and mixtures in there for other
2322key combinations. This may be implemented in a future release but it is a
2323rather left field option and would have to be put into the MIDI library that
2324controls the voice assignments.
2325
2326The arpeggiator integrated into bristol is a general design and will differ
2327from the original. The default settings are 4 buttons controlling the range
2328of the arpeggiation, from 1 to 4 octaves, 4 buttons controlling the mode as
2329Up, Down, Up+Down or Random sequencing of the notes available, and 4 notes
2330that are preloaded into the sequence.
2331
2332Finally there are two global controls that are outside of the memories - the
2333rate and clock source (however externally driven MTC has not been implemented
2334yet). It is noted that the Arpeggiator settings are separate from the sequence
2335information, ie, Up/Down/Rnd, the range and the arpeggiator clock are not the
2336same as the note memory, this is discussed further in the memory setting
2337section below.
2338
2339It is possible to redefine the arpeggiator sequence: select the function
2340button on the right hand side, then select any of the arpeggiator mode buttons,
2341this will initiate the recording. It does not matter which of the mode is
2342selected since they will all start the recording sequence. When you have
2343finished then select the mode button again (you may want to clear the function
2344key if still active). You can record up to 256 steps, either from the GUI
2345keyboard or from a master controller and the notes are saved into a midi
2346key memory.
2347
2348There is no capability to edit the sequences once they have been entered, that
2349level of control is left up to separate MIDI sequencers for which there are
2350many available on Linux. Also, the note memory is actually volatile and will
2351be lost when the emulation exits. If you want to save the settings then you
2352have to enter them from the GUI keyboard or make sure that the GUI is linked
2353up to the master keyboard MIDI interface - you need to be able to see the
2354GUI keyboard following the notes pressed on the master keyboard since only
2355when the GUI sees the notes can it store them for later recall. If the GUI
2356did view the sequence entered here then it will be saved with the patch in
2357a separate file (so that it can be used with other bristol synths).
2358
2359In addition to the Arpeggiator there is the 'Chord' control. The original
2360synth had two green panel buttons labelled 'Hold', they were actually similar
2361to the sustain pedal on a MIDI keyboard or piano, with one for each layer of
2362the synth. They have been redefined here as Chord memory. When activated the
2363layer will play a chord of notes for every key press. The notes are taken from
2364separate chord memory in the Arpeggiator sequencer. The result is very similar
2365to the Unison mode where every voice is activated for a single key, the
2366difference here is that every voice may be playing a different note to give
2367phat chords. To configure a chord you enable the function key and the target
2368Hold button to put the synth into chord learning mode, play a set of notes
2369(you don't have to hold them down), and click again to finalise the chord.
2370If there are more chord notes than voices available then all voices will
2371activate. If there are more voices than notes then you will be able to play
2372these chord polyphonically, for example, if you have 8 voices and entered
2373just 4 chorded notes then you will have 2 note polyphony left. You should
2374also be able to play arpeggiations of chords. The maximum number of notes
2375in a chord is 8.
2376
2377The synth has a modifier panel which functions as performance options which
2378can be applied selectively to different layers:
2379
2380 Bender:
2381 This is the depth of the settings and is mapped by the engine to
2382 continuous controller 1 - the 'Mod' wheel. The emulation also tracks
2383 the pitch wheel separately.
2384
2385 Bend to VCO
2386 This applies an amount of pitch bend from the Mod wheel selectively
2387 to either VCO-1 and/or VCO-2. These settings only affect the Mod
2388 layers selected from the main panel. Subtle modifications applied in
2389 different amounts to each oscillator can widen the sound considerable
2390 by introducing small amounts of oscillator phasing.
2391
2392 Bend to VCF
2393 Affects the depth of cutoff to the filter with on/off available. Again
2394 only applies to layers activate with the Mod setting.
2395
2396 LFO to VCO:
2397 The mod panel has a second global LFO producing a sine wave. This can
2398 be driven in selectable amounts to both VCO simultaneously. Layers are
2399 selected from the Mod buttons.
2400
2401 LFO to VCF:
2402 The LFO can be driven in selectable amounts to both VCO or to the VCF.
2403 Layers are selected from the Mod buttons.
2404
2405 Delay:
2406 This is the rise time of the LFO from the first note pressed. There is
2407 no apparent frequency control of the second LFO however bristol allows
2408 the frequency and gain of the LFO to track velocity using function B4
2409 (see below for function settings). Since there is only one LFO per
2410 emulation then the velocity tracking can be misleading as it only
2411 tracks from a single voice and may not track the last note. For this
2412 reason it can be disabled. Using a tracking from something like channel
2413 pressure is for future study.
2414
2415 Glide:
2416 Glissando between key frequencies, selectable to be either just to the
2417 upper layer, off, or to both layers.
2418
2419 Transpose:
2420 There are two transpose switches for the lower and upper layers
2421 respectively. The range is +/1 one octave.
2422
2423Modifier panel settings are saved in the synth memories and are loaded with
2424the first memory (ie, with dual loaded memories discussed below). The ability
2425to save these settings in memory is an MKS-80 feature that was not available
2426in either the Jupiter-6 or -8.
2427
2428There are several parts to the synth memories. Layer parameters govern sound
2429generation, synth parameters that govern operating modes such Dual/Split,
2430Solo/Unison etc, Function settings that modify internal operations, the
2431parameters for the mod panel and finally the Arpeggiator sequences. These
2432sequences are actually separate from the arpeggiator settings however that
2433was covered in the notes above.
2434
2435When a patch is loaded then only the layer parameters are activated so that the
2436new sound can be played, and the settings are only for the selected layer. This
2437means any chord or arpeggiation can be tried with the new voice active.
2438
2439When a memory is 'dual loaded' by a double click on the Load button then all
2440the memory settings will be read and activated: the current layer settings,
2441synth settings, operational parameters including the peer layer parameters
2442for dual/split configurations. Dual loading of the second layer will only
2443happen if the memory was saved as a split/double with a peer layer active.
2444
2445The emulation adds several recognised Jupiter-6 capabilities that were not a
2446part of the Jupiter-8 product. These are
2447
2448 1. PW setting as well as PWM
2449 2. Cross modulation can be amplified with envelope-1 for FM type sounds
2450 3. Sync can be set in either direction (DCO1 to 2 or DCO2 to 1)
2451 4. The waveforms for DCO 1&2 are not exclusive but mixable
2452 5. The LFO to VCA is a continuous controller rather than stepped
2453 6. The envelope keyboard tracking is continuous rather than on/off
2454 7. The filter option is multimode LP/BP/HP rather than 12/24dB
2455 8. Layer detune is configurable
2456 9. Layer transpose switches are available
2457 10. Arpeggiator is configurable on both layers
2458
2459Beyond these recognised mods it is also possible to select any/all DCO
2460transpositions which further fattens up the sound as it allows for more
2461harmonics. There is some added detune between the waveforms with its depth
2462being a function of the -detune setting. Separate Pan and Balance controls
2463have been implemented, Pan is the stereo positioning and is configurable per
2464layer. Balance is the relative gain between each of the layers.
2465
2466There are several options that can be configured from the 'f' button
2467in the MIDI section. When you push the f(n) button then the patch and bank
2468buttons will not select memory locations but display the on/off status of 16
2469algorithmic changes to the emulation. Values are saved in the synth memories.
2470These are bristol specific modifications and may change between releases unless
2471otherwise documented.
2472
2473F(n):
2474
2475 f(p1): Env-1 retriggers
2476 f(p2): Env-1 conditionals
2477 f(p3): Env-1 attack sensitivity
2478 f(p4): Env-2 retriggers
2479 f(p5): Env-2 conditionals
2480 f(p6): Env-2 attack sensitivity
2481 f(p7): Noise per voice/layer
2482 f(p8): Noise white/pink
2483
2484 f(b1): LFO-1 per voice/layer
2485 f(b2): LFO-1 Sync to Note ON
2486 f(b3): LFO-1 velocity tracking
2487 f(b4): Arpeggiator retrigger
2488 f(b5): LFO-2 velocity tracking
2489 f(b6): NRP enable
2490 f(b7): Debug MIDI
2491 f(b8): Debug GUI controllers
2492
2493The same function key also enables the learning function of the arpeggiator
2494and chord memory, as explained above. When using the arpeggiator you may want
2495to test with f(b4) enabled, it will give better control of the filter envelope.
2496
2497
2498Other differences to the original are the Hold keys on the front panel. These
2499acted as sustain pedals however for the emulation that does not function very
2500well. With the original the buttons were readily available whilst playing and
2501could be used manually, something that does not work well with a GUI and a
2502mouse. For this reason they were re-used for 'Unison Chording' discussed above.
2503Implementing them as sustain pedals would have been an easier if less flexible
2504option and users are advised that the bristol MIDI library does recognise the
2505sustain controller as the logical alternative here.
2506
2507Another difference would be the quality of the sound. The emulation is a lot
2508cleaner and not as phat as the original. You might say it sounds more like
2509something that comes from Uranus rather than Jupiter and consideration was
2510indeed given to a tongue in cheek renaming of the emulation..... The author is
2511allowed this criticism as he wrote the application - as ever, if you want the
2512original sound then buy the original synth (or get Rolands own emulation?).
2513
2514A few notes are required on oscillator sync since by default it will seem to
2515be quite noisy. The original could only product a single waveform at a single
2516frequency at any one time. Several emulators, including this one, use a bitone
2517oscillator which generates complex waveforms. The Bristol Bitone can generate
2518up to 4 waveforms simultaneously at different levels for 5 different harmonics
2519and the consequent output is very rich, the waves can be slightly detuned,
2520the pulse output can be PW modulated. As with all the bristol oscillators that
2521support sync, the sync pulse is extracted as a postive leading zero crossing.
2522Unfortunately if the complex bitone output is used as input to sync another
2523oscillator then the result is far too many zero crossings to extract a good
2524sync. For the time being you will have to simplify the sync source to get a
2525good synchronised output which itself may be complex wave. A future release
2526will add a sync signal from the bitone which will be a single harmonic at the
2527base frequency and allow both syncing and synchronised waveform outputs to be
2528arbitrary.
2529
2530
2531
2532
2533 CRUMAR BIT-1, BIT-99, BIT-100
2534 -----------------------------
2535
2536I was considering the implementation of the Korg-800, a synth I used to borrow
2537without having due respect for it - it was a late low cost analogue having
2538just one filter for all the notes and using the mildly annoying data entry
2539buttons and parameter selectors. Having only one filter meant that with key
2540tracking enabled the filter would open up as different keys were pressed,
2541wildly changing the sound of active notes. Anyway, whilst considering how to
2542implement the entry keys (and having features like the mouse tracking the
2543selectors of the parameter graphics) I was reminded of this synthesizer. It
2544was developed by Crumar but released under the name 'Bit' as the Crumar name
2545was associated with cheesy roadrunner electric pianos at the time (also
2546emulated by Bristol). This came out at the same time as the DX-7 but for
2547half the price, and having the split and layer facilities won it several awards
2548that would otherwise have gone to the incredibly innovative DX. However with
2549the different Crumar models being released as the digital era began they kind
2550of fell between the crack. It has some very nice mod features though, it was
2551fun to emulate and hopefully enjoyable to play with.
2552
2553As a side note, the Korg Poly-800 is now also emulated by bristol
2554
2555A quick rundown of the Bit features are below. The different emulated models
2556have slightly different default parameter values and/or no access to change
2557them:
2558
2559 Two DCO with mixed waveforms.
2560 VCF with envelope
2561 VCA with envelope
2562 Two LFO able to mod all other components, controlled by the wheel and key
2563 velocity, single waveform, one had ramp and the other sawtooth options.
2564
2565The envelopes were touch sensitive for gain but also for attack giving plenty
2566of expressive capabilities. The bristol envelope, when configured for velocity
2567sensitive parameters (other than just gain) will also affect the attack rate.
2568
2569The front panel had a graphic that displayed all the available parameters and
2570to change then you had to select the "Address" entry point then use the up/down
2571entry buttons to change its value. Bristol uses this with the addition that the
2572mouse can click on a parameter to start entering modifications to it.
2573
2574The emulation includes the 'Compare' and 'Park' features although they are a
2575little annoying without a control surface. They work like this (not quite the
2576same as the original): When you select a parameter and change it's value then
2577the changes are not actually made to the active program, they just change the
2578current sounds. The Compare button can be used to flip between the last loaded
2579value and the current modified one to allow you to see if you prefer the sound
2580before or after the modification.
2581
2582If you do prefer the changes then to keep them you must "Park" them into the
2583running program before saving the memory. At the time of writing the emulation
2584emulated the double click to park&write a memory, however it also has an actual
2585Save button since 'Save to Tape' is not a feature here. You can use park and
2586compare over dual loaded voices: unlike the original, which could only support
2587editing of sounds when not in split/double, this emulation allows you to edit
2588both layers by selecting the upper/lower entry buttons and then using the
2589sensitive panel controls to select the addressed parameters. This is not the
2590default behaviour, you first have to edit address 102 and increment it. Then,
2591each layer can be simultaneously edited and just needs to be parked and saved
2592separately. The Park/Compare cache can be disabled by editing parameter DE 101,
2593changes are then made to the synth memory and not the cache.
2594
2595The memories are organised differently to the original. It had 99 memories, and
2596the ones from 75 and above were for Split and Layered memories. Bristol can
2597have all memories as Split or Layer. When you save a memory it is written to
2598memory with a 'peer' program locator. When you load it with a single push on
2599the Load button it returns to the active program, but if you double click then
2600its 'peer' program is loaded into the other layer: press Load once to get the
2601first program entered, then press it again - the Split/Layer will be set to
2602the value from the first program and the second layer will be loaded. This
2603naturally requires that the first memory was saved with Split/Layer enabled.
2604It is advised (however not required) that this dual loading is done from the
2605lower layer. This sequence will allow the lower layer to configure certain
2606global options that the upper layer will not overwrite, for example the layer
2607volumes will be select from the lower layer when the upper layer is dual
2608loaded.
2609
2610For MIDI program change then since this quirky interface cannot be emulated
2611then the memories above 75 will be dual loaded, the rest will be single loaded.
2612
2613Bristol will also emulate a bit-99 and a Bit-99m2 that includes some parameter
2614on the front panel that were not available on the original. The engine uses the
2615exact same algorithm for all emulations but the GUI presents different sets of
2616parameters on the front panel. Those that are not displayed can only be accessed
2617from the data entry buttons. The -99m2 put in a few extra features (ie, took a
2618few liberties) that were not in the original:
2619
2620 DCO adds PWM from the LFO, not in the original
2621 DCO-2 adds Sync to DCO-1, also not in the original
2622 DCO-2 adds FM from DCO-1
2623 DCO add PWM from Envelope
2624 Glide has been added
2625 DCO harmonics are not necessarily exclusive
2626 Various envelope option for LFO
2627 S&H LFO modulation
2628
2629The reason these were added was that bristol could already do them so were
2630quite easy to incorporate, and at least gave two slightly different emulations.
2631
2632The oscillators can work slightly differently as well. Since this is a purely
2633digital emulations then the filters are a bit weak. This is slightly compensated
2634by the ability to configure more complex DCO. The transpose selectors (32', 16',
26358' and 2') were exclusive in the original. That is true here also, however if
2636controllers 84 and 85 are set to zero then they can all work together to fatten
2637out the sound. Also, the controllers look like boolean however that is only the
2638case if the data entry buttons are used, if you change the value with the data
2639entry pot then they act more like continuous drawbars, a nice effect however
2640the display will not show the actual value as the display remains boolean, you
2641have to use your ear. The square wave is exclusive and will typically only
2642function on the most recently selected (ie, typically highest) harmonic.
2643
2644The same continuous control is also available on the waveform selectors. You
2645can mix the waveform as per the original however the apparent boolean selectors
2646are again continuous from 0.0 to 1.0. The net result is that the oscillators
2647are quite Voxy having the ability to mix various harmonic levels of different
2648mixable waveforms.
2649
2650The stereo mode should be correctly implemented too. The synth was not really
2651stereo, it had two outputs - one for each layer. As bristol is stereo then each
2652layer is allocated to the left or right channel. In dual or split they came
2653out separate feeds if Stereo was selected. This has the rather strange side
2654effect of single mode with 6 voices. If stereo is not selected then you have
2655a mono synth. If stereo is selected then voices will exit from a totally
2656arbitrary output depending on which voices is allocated to each note.
2657In contrast to the original the Stereo parameter is saved with the memory and
2658if you dual load a split/layer it is taken from the first loaded memory only.
2659The implementation actually uses two different stereo mixes selectable with the
2660Stereo button: Mono is a centre pan of the signal and Stereo pans hardleft and
2661hardright respectively. These mixes can be changed with parameters 110 to 117
2662using extended data entry documented below.
2663
2664The default emulation takes 6 voices for unison and applies 3+3 for the split
2665and double modes. You can request more, for example if you used '-voices 16'
2666at startup then you would be given 8+8. As a slight anomaly you cant request 32
2667voices - this is currently interpreted as the default and gives you 3+3.
2668
2669The bit-1 did not have the Stereo control - the controller presented is the
2670Unison button. You can configure stereo from the extended data entry ID 110 and
2671111 which give the LR channel panning for 'Mono' setting, it should default to
2672hard left and right panning. Similarly the -99 emulations do not have a Unison
2673button, the capability is available from DE 80.
2674
2675The memories for the bit-1 and bit-99 should be interchangeable however the
2676code maintains separate directories.
2677
2678There are three slightly different Bit GUI's. The first is the bit-1 with a
2679limited parameter set as it only had 64 parameters. The second is the bit-99
2680that included midi and split options in the GUI and has the white design that
2681was an offered by Crumar. The third is a slightly homogenous design that is
2682specific to bristol, similar to the black panelled bit99 but with a couple of
2683extra parameters. All the emulations have the same parameters, some require you
2684use the data entry controls to access them. This is the same as the original,
2685there were diverse parameters that were not in memories that needed to be
2686entered manually every time you wanted the feature. The Bristol Bit-99m2 has
2687about all of the parameters selectable from the front panel however all of the
2688emulations use the same memories so it is not required to configure them at
2689startup (ie, they are saved). The emulation recognises the following parameters:
2690
2691 Data Entry 1 LFO-1 triangle wave selector (exclusive switch)
2692 Data Entry 2 LFO-1 ramp wave selector (exclusive switch)
2693 Data Entry 3 LFO-1 square wave selector (exclusive switch)
2694 Data Entry 4 LFO-1 route to DCO-1
2695 Data Entry 5 LFO-1 route to DCO-2
2696 Data Entry 6 LFO-1 route to VCF
2697 Data Entry 7 LFO-1 route to VCA
2698 Data Entry 8 LFO-1 delay
2699 Data Entry 9 LFO-1 frequency
2700 Data Entry 10 LFO-1 velocity to frequency sensitivity
2701 Data Entry 11 LFO-1 gain
2702 Data Entry 12 LFO-1 wheel to gain sensitivity
2703
2704 Data Entry 13 VCF envelope Attack
2705 Data Entry 14 VCF envelope Decay
2706 Data Entry 15 VCF envelope Sustain
2707 Data Entry 16 VCF envelope Release
2708 Data Entry 17 VCF velocity to attack sensitivity (and decay/release)
2709 Data Entry 18 VCF keyboard tracking
2710 Data Entry 19 VCF cutoff
2711 Data Entry 20 VCF resonance
2712 Data Entry 21 VCF envelope amount
2713 Data Entry 22 VCF velocity to gain sensitivity
2714 Data Entry 23 VCF envelope invert
2715
2716 Data Entry 24 DCO-1 32' harmonic
2717 Data Entry 25 DCO-1 16' harmonic
2718 Data Entry 26 DCO-1 8' harmonic
2719 Data Entry 27 DCO-1 4' harmonic
2720 Data Entry 28 DCO-1 Triangle wave
2721 Data Entry 29 DCO-1 Ramp wave
2722 Data Entry 30 DCO-1 Pulse wave
2723 Data Entry 31 DCO-1 Frequency 24 semitones
2724 Data Entry 32 DCO-1 Pulse width
2725 Data Entry 33 DCO-1 Velocity PWM
2726 Data Entry 34 DCO-1 Noise level
2727
2728 Data Entry 35 DCO-2 32' harmonic
2729 Data Entry 36 DCO-2 16' harmonic
2730 Data Entry 37 DCO-2 8' harmonic
2731 Data Entry 38 DCO-2 4' harmonic
2732 Data Entry 39 DCO-2 Triangle wave
2733 Data Entry 40 DCO-2 Ramp wave
2734 Data Entry 41 DCO-2 Pulse wave
2735 Data Entry 42 DCO-2 Frequency 24 semitones
2736 Data Entry 43 DCO-2 Pulse width
2737 Data Entry 44 DCO-2 Env to pulse width
2738 Data Entry 45 DCO-2 Detune
2739
2740 Data Entry 46 VCA velocity to attack sensitivity (and decay/release)
2741 Data Entry 47 VCA velocity to gain sensitivity
2742 Data Entry 48 VCA overall gain ADSR
2743 Data Entry 49 VCA Attack
2744 Data Entry 50 VCA Decay
2745 Data Entry 51 VCA Sustain
2746 Data Entry 52 VCA Release
2747
2748 Data Entry 53 LFO-2 triangle wave selector (exclusive switch)
2749 Data Entry 54 LFO-2 saw wave selector (exclusive switch)
2750 Data Entry 55 LFO-2 square wave selector (exclusive switch)
2751 Data Entry 56 LFO-2 route to DCO-1
2752 Data Entry 57 LFO-2 route to DCO-2
2753 Data Entry 58 LFO-2 route to VCF
2754 Data Entry 59 LFO-2 route to VCA
2755 Data Entry 60 LFO-2 delay
2756 Data Entry 61 LFO-2 frequency
2757 Data Entry 62 LFO-2 velocity to frequency sensitivity
2758 Data Entry 63 LFO-2 gain
2759 Data Entry 12 LFO-2 wheel to gain sensitivity
2760
2761 Data Entry 64 Split
2762 Data Entry 65 Upper layer transpose
2763 Data Entry 66 Lower Layer gain
2764 Data Entry 67 Upper Layer gain
2765
2766The following were visible in the Bit-99 graphics only:
2767
2768 Data Entry 68 MIDI Mod wheel depth
2769 Data Entry 69 MIDI Velocity curve (0 = soft, 10=linear, 25 = hard)
2770 Data Entry 70 MIDI Enable Debug
2771 Data Entry 71 MIDI Enable Program Change
2772 Data Entry 72 MIDI Enable OMNI Mode
2773 Data Entry 73 MIDI Receive channel
2774
2775 Data Entry 74 MIDI Mem Search Upwards
2776 Data Entry 75 MIDI Mem Search Downwards
2777 Data Entry 76 MIDI Panic (all notes off)
2778
2779Most of the MIDI options are not as per the original. This is because they are
2780implemented in the bristol MIDI library and not the emulation.
2781
2782The following were added which were not really part of the Bit specifications
2783so are only visible on the front panel of the bit100. For the other emulations
2784they are accessible from the address entry buttons.
2785
2786 Data Entry 77 DCO-1->DCO-2 FM
2787 Data Entry 78 DCO-2 Sync to DCO-1
2788 Data Entry 79 Keyboard glide
2789 Data Entry 80 Unison
2790
2791 Data Entry 81 LFO-1 SH
2792 Data Entry 82 LFO-1 PWM routing for DCO-1
2793 Data Entry 83 LFO-1 PWM routing for DCO-2
2794 Data Entry 84 LFO-1 wheel tracking frequency
2795 Data Entry 85 LFO-1 velocity tracking gain
2796 Data Entry 86 LFO-1 per layer or per voice
2797
2798 Data Entry 87 LFO-2 SH
2799 Data Entry 88 LFO-2 PWM routing for DCO-1
2800 Data Entry 89 LFO-2 PWM routing for DCO-2
2801 Data Entry 90 LFO-2 wheel tracking frequency
2802 Data Entry 91 LFO-2 velocity tracking gain
2803 Data Entry 92 LFO-2 per layer or per voice
2804
2805 Data Entry 93 ENV-1 PWM routing for DCO-1
2806 Data Entry 94 ENV-1 PWM routing for DCO-2
2807
2808 Data Entry 95 DCO-1 restricted harmonics
2809 Data Entry 96 DCO-2 restricted harmonics
2810
2811 Data Entry 97 VCF Filter type
2812 Data Entry 98 DCO-1 Mix
2813
2814 Data Entry 99 Noise per layer
2815
2816 Data Entry 00 Extended data entry (above 99)
2817
2818Extended data entry is for all parameters above number 99. Since the displays
2819only have 2 digits it is not totally straightforward to enter these values and
2820they are only available in Single mode, not dual or split - strangely similar
2821to the original specification for editing memories. These are only activated for
2822the lower layer loaded memory, not for dual loaded secondaries or upper layer
2823loaded memories. You can edit the upper layer voices but they will be saved with
2824their original extended parameters. This may seem correct however it is possible
2825to edit an upper layer voice, save it, and have it sound different when next
2826loaded since the extended parameters were taken from a different lower layer.
2827This is kind of intentional but if in doubt then only ever dual load voices from
2828the lower layer and edit them in single mode (not split or layer). Per default
2829the emulation, as per the original, will not allow voice editing in Split or
2830Layer modes however it can be enabled with DE 102.
2831
2832All the Bit emulations recognise extended parameters. They are somewhat in a
2833disorganised list as they were built in as things developed. For the most part
2834they should not be needed.
2835The Bit-100 includes some in its silkscreen, for the others you can access them
2836as follows:
2837
28381. deselect split or double
28392. select addr entry
28403. use 0..9 buttons to enter address 00
28414. increment value to '1'. Last display should show EE (Extended Entry)
2842
28435. select last two digits of desired address with 0-9 buttons
28446. change value (preferably with pot).
2845
28467. when finished, select address 00 again (this is now actually 100) to exit
2847
2848 Data Entry 100 Exit extended data entry
2849 Data Entry 101 enable WriteThru scratchpad (disables park and compare)
2850 Data Entry 102 enable layer edits on Split/Double memories.
2851 Data Entry 103 LFO-1 Sync to note on
2852 Data Entry 104 LFO-2 Sync to note on
2853 Data Entry 105 ENV-1 zero retrigger
2854 Data Entry 106 ENV-2 zero retrigger
2855 Data Entry 107 LFO-1 zero retrigger
2856 Data Entry 108 LFO-2 zero retrigger
2857 Data Entry 109 Debug enable (0 == none, 5 == persistent)
2858
2859 Data Entry 110 Left channel Mono gain, Lower
2860 Data Entry 111 Right channel Mono gain, Lower
2861 Data Entry 112 Left channel Stereo gain, Lower
2862 Data Entry 113 Right channel Stereo gain, Lower
2863 Data Entry 114 Left channel Mono gain, Upper
2864 Data Entry 115 Right channel Mono gain, Upper
2865 Data Entry 116 Left channel Stereo gain, Upper
2866 Data Entry 117 Right channel Stereo gain, Upper
2867 Data Entry 118 Bit-100 flag
2868 Data Entry 119 Temperature sensitivity
2869
2870 Data Entry 120 MIDI Channel tracking layer-2 (same/different channel)
2871 Data Entry 121 MIDI Split point tracking layer-2 (same/different split)
2872 Data Entry 122 MIDI Transpose tracking (layer-2 or both layers) N/A
2873 Data Entry 123 MIDI NRP enable
2874
2875 Data Entry 130 Free Memory Search Up
2876 Data Entry 131 Free Memory Search Down
2877 Data Entry 132 ENV-1 Conditional
2878 Data Entry 133 ENV-2 Conditional
2879 Data Entry 134 LFO-1 ENV Conditional
2880 Data Entry 135 LFO-2 ENV Conditional
2881 Data Entry 136 Noise white/pink
2882 Data Entry 137 Noise pink filter (enable DE 136 Pink)
2883 Data Entry 138 Glide duration 0 to 30 seconds
2884 Data Entry 139 Emulation gain level
2885
2886 Data Entry 140 DCO-1 Square wave gain
2887 Data Entry 141 DCO-1 Subharmonic level
2888 Data Entry 142 DCO-2 Square wave gain
2889 Data Entry 143 DCO-2 Subharmonic level
2890
2891The 150 range will be incorporated when the Arpeggiator code is more stable,
2892currently in development for the Jupiter. This is anticipated in 0.20.4:
2893
2894 Data Entry 150 Arpeggiator Start/Stop
2895 Data Entry 151 Arpeggiator mode D, U/D, U or Random
2896 Data Entry 152 Arpeggiator range 1, 2, 3, 4 octaves
2897 Data Entry 153 Arpeggiator rate
2898 Data Entry 154 Arpeggiator external clock
2899 Data Entry 155 Arpeggiator retrigger envelopes
2900 Data Entry 156 Arpeggiator poly-2 mode
2901 Data Entry 157 Chord Enable
2902 Data Entry 158 Chord Relearn
2903 Data Entry 159 Sequencer Start/Stop
2904 Data Entry 160 Sequencer mode D, U/D, U or Random
2905 Data Entry 161 Sequencer range 1, 2, 3, 4 octaves
2906 Data Entry 162 Sequencer rate
2907 Data Entry 163 Sequencer external clock
2908 Data Entry 164 Sequencer retrigger envelopes
2909 Data Entry 165 Sequencer Relearn
2910
2911The following can be manually configured but are really for internal uses only
2912and will be overwritten when memories are saved to disk. The Split/Join flag,
2913for example, is used by dual loading memories to configure the peer layer to
2914load the memory in DE-198, and the stereo placeholder for configuring the stereo
2915status of any single loaded memory.
2916
2917 Data Entry 193 Reserved: save bit-1 formatted memory
2918 Data Entry 194 Reserved: save bit-99 formatted memory
2919 Data Entry 195 Reserved: save bit-100 formatted memory
2920 Data Entry 196 Reserved: Split/Join flag - internal use
2921 Data Entry 197 Reserved: Stereo placeholder - internal use
2922 Data Entry 198 Reserved: Peer memory pointer - internal use
2923 Data Entry 199 Reserved: DCO-2 Wheel mod (masks entry 12) - internal use
2924
2925The tuning control in the emulation is on the front panel rather than on the
2926rear panel as in the original. It had a keyboard sensitivity pot however that
2927is achieved separately with bristol using velocity curves from the MIDI control
2928settings. The front panel rotary defaults to 0% tuning and is not saved in the
2929memory. The front panel gain controls are also not saved in the memory and
2930default to 0.8 at startup.
2931
2932The net emulation is pretty intensive as it runs with over 150 operational
2933parameters.
2934
2935A few notes are required on oscillator sync since by default it may seem to
2936be quite noisy. The original could only produce a single waveform at a single
2937frequency at any one time. Several emulators, including this one, use a bitone
2938oscillator which generates complex waveforms. The Bristol Bitone can generate
2939up to 4 waveforms simultaneously at different levels for 5 different harmonics
2940and the consequent output is very rich, the waves can be slightly detuned,
2941the pulse output can be PW modulated. As with all the bristol oscillators that
2942support sync, the sync pulse is extracted as a postive leading zero crossing.
2943Unfortunately if the complex bitone output is used as input to sync another
2944oscillator then the result is far too many zero crossings to extract a good
2945sync.
2946Code has been implemented to generate a second sync source using a side output
2947sync wave which is then fed to a sideband sync input on the oscillator, the
2948results are far better
2949
2950
2951
2952
2953 Sequential Circuits Prophet Pro-One
2954 -----------------------------------
2955
2956Sequential circuits released amongst the first truly polyphonic synthesisers
2957where a group of voice circuits (5 to 10 of them) were linked to an onboard
2958computer that gave the same parameters to each voice and drove the notes to
2959each voice from the keyboard. The costs were nothing short of exhorbitant and
2960this lead to Sequential releasing a model with just one voice board as a mono-
2961phonic equivalent. The sales ran up to 10,000 units, a measure of its success
2962and it continues to be recognised alongside the Mini Moog as a fat bass synth.
2963
2964The design of the Prophet synthesisers follows that of the Mini Moog. It has
2965three oscillators one of them as a dedicated LFO. The second audio oscillator
2966can also function as a second LFO, and can cross modulate oscillator A for FM
2967type effects. The audible oscillators have fixed waveforms with pulse width
2968modulation of the square wave. These are then mixed and sent to the filter with
2969two envelopes, for the filter and amplifier.
2970
2971The Pro-1 had a nice bussing matrix where 3 different sources, LFO, Filter Env
2972and Oscillator-B could be mixed in varying amounts to two different modulation
2973busses and each bus could then be chosen as inputs to modulation destinations.
2974One bus was a direct bus from the mixed parameters, the second bus was under
2975the modwheel to give configurable expressive control.
2976
2977LFO:
2978
2979 Frequency: 0.1 to 50 Hz
2980 Shape: Ramp/Triangle/Square. All can be selected, none selected should
2981 give a sine wave
2982
2983Modulations:
2984
2985 Source:
2986
2987 Filter Env amount to Direct or Wheel Mod busses
2988 Oscillator-B amount to Direct or Wheel Mod busses
2989 LFO to Direct amount or Wheel Mod busses
2990
2991 Dest:
2992
2993 Oscillator-A frequency from Direct or Wheel Mod busses
2994 Oscillator-A PWM from Direct or Wheel Mod busses
2995 Oscillator-B frequency from Direct or Wheel Mod busses
2996 Oscillator-B PWM from Direct or Wheel Mod busses
2997 Filter Cutoff from Direct or Wheel Mod busses
2998
2999Osc-A:
3000
3001 Tune: +/-7 semitones
3002 Freq: 16' to 2' in octave steps
3003 Shape: Ramp or Square
3004 Pulse Width: only when Square is active.
3005 Sync: synchronise to Osc-B
3006
3007Osc-B:
3008
3009 Tune: +/-7 semitones
3010 Freq: 16' to 2' in octave steps
3011 Fine: +/- 7 semitones
3012 Shape: Ramp/Triangle/Square
3013 Pulse Width: only when Square is active.
3014 LFO: Lowers frequency by 'several' octaves.
3015 KBD: enable/disable keyboard tracking.
3016
3017Mixer:
3018
3019 Gain for Osc-A, Osc-B, Noise
3020
3021Filter:
3022
3023 Cutoff: cuttof frequency
3024 Res: Resonance/Q/Emphasis
3025 Env: amount of modulation affecting to cutoff.
3026 KBD: amount of keyboard trackingn to cutoff
3027
3028Envelopes: One each for PolyMod (filter) and amplifier.
3029
3030 Attack
3031 Decay
3032 Sustain
3033 Release
3034
3035Sequencer:
3036
3037 On/Off
3038 Record Play
3039 Rate configured from LFO
3040
3041Arpeggiator:
3042
3043 Up/Off/UpDown
3044 Rate configured from LFO
3045
3046Glide:
3047
3048 Amount of portamento
3049 Auto/Normal - first key will/not glide.
3050
3051Global:
3052
3053 Master Tune
3054 Master Volume
3055
3056
3057Memories are loaded by selecting the 'Bank' button and typing in a two digit
3058bank number followed by load. Once the bank has been selected then 8 memories
3059from the bank can be loaded by pressing another memory select and pressing
3060load. The display will show free memories (FRE) or programmed (PRG).
3061There is an additional Up/Down which scan for the next program and a 'Find'
3062key which will scan up to the next unused memory location.
3063
3064The original supported two sequences, Seq1 and Seq2, but these have not been
3065implemented. Instead the emulator will save a sequence with each memory location
3066which is a bit more flexible if not totally in the spirit of the original.
3067
3068The Envelope amount for the filter is actually 'Mod Amount'. To get the filter
3069envelope to drive the filter it must be routed to the filter via a mod bus. This
3070may differ from the original.
3071Arpeggiator range is two octaves.
3072The Mode options may not be correctly implemented due to the differences in
3073the original being monophonic and the emulator being polyphonic. The Retrig is
3074actually 'rezero' since we have separate voices. Drone is a Sustain key that
3075emulates a sustain pedal.
3076Osc-B cannot modulate itself in polyphonic mode (well, it could, it's just that
3077it has not been coded that way).
3078The filter envelope is configured to ignore velocity.
3079
3080The default filters are quite expensive. The -lwf option will select the less
3081computationally expensive lightweight Chamberlain filters which have a colder
3082response but require zonks fewer CPU cycles.
3083
3084
3085
3086
3087 Moog Voyager (Bristol "Explorer")
3088 ---------------------------------
3089
3090This was Robert Moog's last synth, similar in build to the Mini but created
3091over a quarter of a century later and having far, far more flexibility. It
3092was still monophonic, a flashback to a legendary synth but also a bit like
3093Bjorn Borg taking his wooden tennis racket back to Wimbledon long after having
3094retired and carbon fibre having come to pass. I have no idea who uses it and
3095Bjorn also crashed out in the first round. The modulation routing is exceptional
3096if not exactly clear.
3097
3098The Voyager, or Bristol Explorer, is definitely a child of the Mini. It has
3099the same fold up control panel, three and half octave keyboard and very much
3100that same look and feel. It follows the same rough design of three oscillators
3101mixed with noise into a filter with envelopes for the filter and amplifier.
3102In contrast there is an extra 4th oscillator, a dedicated LFO bus also Osc-3
3103can still function as a second LFO here. The waveforms are continuously
3104selected, changing gradually to each form: bristol uses a form of morphing
3105get get similar results. The envelopes are 4 stage rather than the 3 stage
3106Mini, and the effects routing bears no comparison at all, being far more
3107flexible here.
3108
3109Just because its funny to know, Robert Moog once stated that the most difficult
3110part of building and releasing the Voyager was giving it the title 'Moog'. He
3111had sold his company in the seventies and had to buy back the right to use his
3112own name to release this synthesiser as a Moog, knowing that without that title
3113it probably would not sell quite as well as it didn't.
3114
3115Control:
3116
3117 LFO:
3118 Frequency
3119 Sync: LFO restarted with each keypress.
3120
3121 Fine tune +/- one note
3122 Glide 0 to 30 seconds.
3123
3124Modulation Busses:
3125
3126 Two busses are implemented. Both have similar capabilities but one is
3127 controlled by the mod wheel and the other is constantly on. Each bus has
3128 a selection of sources, shaping, destination selection and amount.
3129
3130 Wheel Modulation: Depth is controller by mod wheel.
3131
3132 Source: Triwave/Ramp/Sample&Hold/Osc-3/External
3133 Shape: Off/Key control/Envelope/On
3134 Dest: All Osc Frequency/Osc-2/Osc-3/Filter/FilterSpace/Waveform (*)
3135 Amount: 0 to 1.
3136
3137 Constant Modulation: Can use Osc-3 as second LFO to fatten sound.
3138
3139 Source: Triwave/Ramp/Sample&Hold/Osc-3/External
3140 Shape: Off/Key control/Envelope/On
3141 Dest: All Osc Frequency/Osc-2/Osc-3/Filter/FilterSpace/Waveform (*)
3142 Amount: 0 to 1.
3143
3144 * Destination of filter is the cutoff frequency. Filter space is the
3145 difference in cutoff of the two layered filters. Waveform destination
3146 affects the continuously variable oscillator waveforms and allows for
3147 Pulse Width Modulation type effects with considerably more power since
3148 it can affect ramp to triangle for example, not just pulse width.
3149
3150Oscillators:
3151
3152 Oscillator 1:
3153 Octave: 32' to 1' in octave steps
3154 Waveform: Continuous between Triangle/Ramp/Square/Pulse
3155
3156 Oscillator 2:
3157 Tune: Continuous up/down 7 semitones.
3158 Octave: 32' to 1' in octave steps
3159 Waveform: Continuous between Triangle/Ramp/Square/Pulse
3160
3161 Oscillator 3:
3162 Tune: Continuous up/down 7 semitones.
3163 Octave: 32' to 1' in octave steps
3164 Waveform: Continuous between Triangle/Ramp/Square/Pulse
3165
3166 Sync: Synchronise Osc-2 to Osc-1
3167 FM: Osc-3 frequency modulates Osc-1
3168 KBD: Keyboard tracking Osc-3
3169 Freq: Osc-3 as second LFO
3170
3171Mixer:
3172
3173 Gain levels for each source: Osc-1/2/3, noise and external input.
3174
3175Filters:
3176
3177 There are two filters with different configuration modes:
3178
3179 1. Two parallel resonant lowpass filters.
3180 2. Serialised HPF and resonant LPF
3181
3182 Cutoff: Frequency of cutoff
3183 Space: Distance between the cutoff of the two filters.
3184 Resonance: emphasis/Q.
3185 KBD tracking amount
3186 Mode: Select between the two operating modes.
3187
3188Envelopes:
3189
3190 Attack
3191 Decay
3192 Sustain
3193 Release
3194
3195 Amount to filter (positive and negative control)
3196
3197 Velocity sensitivity of amplifier envelope.
3198
3199Master:
3200
3201 Volume
3202 LFO: Single LFO or one per voice (polyphonic operation).
3203 Glide: On/Off portamento
3204 Release: On/Off envelope release.
3205
3206The Explorer has a control wheel and a control pad. The central section has
3207the memory section plus a panel that can modify any of the synth parameters as
3208a real time control. Press the first mouse key here and move the mouse around
3209to adjust the controls. Default values are LFO frequency and filter cutoff
3210but values can be changed with the 'panel' button. This is done by selecting
3211'panel' rather than 'midi', and then using the up/down keys to select parameter
3212that will be affected by the x and y motion of the mouse. At the moment the
3213mod routing from the pad controller is not saved to the memories, and it will
3214remain so since the pad controller is not exactly omnipresent on MIDI master
3215keyboards - the capabilities was put into the GIU to be 'exact' to the design.
3216
3217This synth is amazingly flexible and difficult to advise on its best use. Try
3218starting by mixing just oscillator 1 through to the filter, working on mod
3219and filter options to enrich the sound, playing with the oscillator switches
3220for different effects and then slowly mix in oscillator 2 and 3 as desired.
3221
3222Memories are available via two grey up/down selector buttons, or a three digit
3223number can be entered. There are two rows of black buttons where the top row
3224is 0 to 4 and the second is 5 to 9. When a memory is selected the LCD display
3225will show whether it is is free (FRE) or programmed already (PRG).
3226
3227
3228
3229
3230 Moog Sonic-6
3231 ------------
3232
3233This original design was made by an engineer who had previously worked with
3234Moog on the big modular systems, Gene Zumchek. He tried to get Moog Inc to
3235develop a small standalone unit rather than the behemoths however he could
3236not get heard. After leaving he built a synth eventually called a Sonic-5 that
3237did fit the bill but sales volumes were rather small. He had tied up with a
3238business manager who worked out that the volume was largely due to the name
3239not being known, muSonics.
3240This was quickly overcome by accident. Moog managed to run his company into
3241rather large debt and the company folded. Bill Waytena, working with Zumcheck,
3242gathered together the funding needed to buy the remains of the failed company
3243and hence Moog Inc was labled on the rebadged Sonic-6. Zumcheck was eventually
3244forced to leave this company (or agreed to) as he could not work with Moog.
3245After a few modifications Bob Moog actually used this unit quite widely for
3246lecturing on electronic music. For demonstrative purposes it is far more
3247flexible than any of Moog's own non-modular designs and it was housed in a
3248transport case rather than needing a shipping crate as the modular systems
3249required.
3250
3251The emulation features are given below, but first a few of the differences to
3252the original
3253
3254 Added a mod wheel that can drive GenX/Y.
3255 PWM is implemented on the oscillator B
3256 Installed an ADSR rather than AR, selectable.
3257 No alternative scalings - use scala file support
3258 Not duo or dia phonic. Primarily poly with separated glide.
3259
3260The original was duophonic, kind of. It had a keyboard with high note and low
3261note precedence and the two oscillators could be driven from different notes.
3262Its not really duophony and was reportedly not nice to play but it added some
3263flexibility to the instrument. This features was dropped largley because it
3264is ugly to emulate in a polyphonic environment but the code still has glide
3265only on Osc-B. It has the two LFO that can be mixed, or at full throw of the
3266GenXY mixer they will link X->A and Y->B giving some interesting routing, two
3267osc each with their own LFO driving the LFO from the mod wheel or shaping it
3268with the ADSR. Playing around should give access to X driving Osc-A, then
3269Osc-A and GenY driving Osc-B with Mod and shaping for some investigation of
3270FM synthesis. The gruesome direct output mixer is still there, having the osc
3271and ring-mod bypass the filter and amplifier completely (or can be mixed back
3272into the 'actuated' signal).
3273
3274There is currently no likely use for an external signal even though the
3275graphics are there.
3276
3277The original envelope was AR or ASR. The emulator has a single ADSR and a
3278control switch to select AR (actually AD), ASR, ADSD (MiniMoog envelope) or
3279ADSR.
3280
3281Generator-Y has a S/H function on the noise source for a random signal which
3282replaced the square wave. Generator-X still has a square wave.
3283
3284Modulators:
3285
3286 Two LFO, X and Y:
3287
3288 Gen X:
3289 Tri/Ramp/Saw/Square
3290 Tuning
3291 Shaping from Envelope or Modwheel
3292
3293 Gen Y:
3294 Tri/Ramp/Saw/Rand
3295 Tuning
3296 Shaping from Envelope or Modwheel
3297
3298 Master LFO frequency
3299
3300 GenXY mixer
3301
3302 Two Oscillators, A and B
3303
3304 Gen A:
3305 Tri/Ramp/Pulse
3306 PulseWidth
3307 Tuning
3308 Transpose 16', 8', 4' (*)
3309
3310 Mods:
3311
3312 Envelope
3313 GenXY(or X)
3314 Low frequency, High Frequency (drone), KBD Tracking
3315
3316 Gen B:
3317 Tri/Ramp/Pulse
3318 PulseWidth
3319 Tuning
3320 Transpose 16' 8', 4'
3321
3322 Mods:
3323
3324 Osc-B
3325 GenXY(or Y)
3326 PWM
3327
3328 GenAB mix
3329
3330 Ring Mod:
3331
3332 Osc-B/Ext
3333 GenXY/Osc-A
3334
3335 Noise
3336
3337 Pink/White
3338
3339 Mixer
3340
3341 GenAB
3342 RingMod
3343 External
3344 Noise
3345
3346 Filter (**)
3347
3348 Cutoff
3349 Emphasis
3350
3351 Mods:
3352
3353 ADSR
3354 Keyboard tracking
3355 GenXY
3356
3357 Envelope:
3358
3359 AR/ASR/ADSD/ADSR
3360 Velociy on/off
3361
3362 Trigger:
3363
3364 GenX
3365 GenY
3366 Kbd (rezero only)
3367
3368 Bypass (key gated audio)
3369
3370 Direct Output Mixer
3371
3372 Osc-A
3373 Osc-B
3374 RingMod
3375
3376
3377The keyboard has controls for
3378
3379 Glide (Osc-B only)
3380 Master Volume
3381 PitchWheel
3382 ModWheel (gain modifier on LFO)
3383
3384 Global Tuning
3385
3386 MultiLFO X and Y
3387
3388* The oscillator range was +/-2 octave switch and a +/-1 octave pot. This
3389emulator has +/-1 octave switch and +/-7 note pot. That may change in a future
3390release to be more like the original, probably having a multiway 5 stage octave
3391selector.
3392
3393** The filter will self oscillate at full emphasis however this is less
3394prominent at lower frequencies (much like the Moog ladder filter). The filter
3395is also 'not quite' in tune when played as an oscillator, this will also change
3396in a future release.
3397
3398There may be a reverb on the emulator. Or there may not be, that depends on
3399release. The PitchWheel is not saved in the memories, the unit is tuned on
3400startup and this will maintain tuning to other instruments. The MultiLFO allow
3401you to configure single LFO per emulation or one per voice, independently.
3402Having polyphony means you can have the extra richness of independent LFO per
3403voice however that does not work well if they are used as triggers, for example,
3404you end up with a very noisy result. With single triggers for all voices the
3405result is a lot more predictable.
3406
3407The Sonic-6 as often described as having bad tuning, that probably depends on
3408model since different oscillators were used at times. Also, different units
3409had different filters (Zumchek used a ladder of diodes to overcome the Moog
3410ladder of transister patent). The original was often described as only being
3411useful for sound effects. Personally I don't think that was true however the
3412design is extremely flexible and the mods are applied with high gains so to
3413get subtle sounds they only have to be applied lightly. Also, this critique
3414was in comparison to the Mini which was not great for sound effects since it,
3415in contrast, had very little in the way of modifiers.
3416
3417The actual mod routing here is very rich. The two LFO can be mixed to provide
3418for more complex waves and have independent signal gain from the ADSR. To go
3419a step further it is possible to take the two mixed LFO into Osc-A, configure
3420that as an LFO and feed it into Osc-B for some very complex mod signals. That
3421way you can get a frequency modulated LFO which is not possible from X or Y. As
3422stated, if these are applied heavily you will get ray guns and car alarms but
3423in small amounts it is possible to just shape sounds. Most of the mod controls
3424have been made into power functions to give more control at small values.
3425
3426The memory panel gives access to 72 banks of 8 memories each. Press the Bank
3427button and two digits for the bank, then just select the memory and press Load.
3428You can get the single digit banks by selecting Bank->number->Bank. There is
3429a save button which should require a double click but does not yet (0.30.0),
3430a pair of buttons for searching up and down the available memories and a button
3431called 'Find' which will select the next available free memory.
3432
3433Midi options include channel, channel down and, er, thats it.
3434
3435
3436
3437
3438 CRUMAR TRILOGY
3439 --------------
3440
3441This text is primarily that of the Stratus since the two synths were very
3442similar. This is the bigger brother having all the same features with the added
3443string section. There were some minor differences in the synth circuits for
3444switchable or mixable waveforms.
3445
3446This unit is a hybrid synth/organ/string combo, an early polyphonic using an
3447organ divider circuit rather than independent VCO and having a set of filters
3448and envelope for the synth sounds, most manufacturers came out with similar
3449designs. The organ section was generally regarded as pretty bad here, there
3450were just five controls, four used for the volume of 16, 8, 4 and 2 foot
3451harmonics and a fifth for overall organ volume. The synth section had 6 voices
3452and some quite neat little features for a glide circuitry and legato playing
3453modes. The string section could mix 3 waveforms with vibrato on some so when
3454mixed with the straight waveform would produce phasing.
3455
3456The emulator consists of two totally separate layers, one emulating the organ
3457circuitry and another the synth. The organ has maximum available polyphony as
3458the algorithm is quite lightweight even though diverse liberties have been
3459taken to beef up the sound. The synth section is limited to 6 voices unless
3460otherwise specified at run time. The organ circuitry is used to generate the
3461string section.
3462
3463The legato playing modes affects three sections, the LFO modulation, VCO
3464selection and glide:
3465
3466LFO: this mod has a basic envelope to control the gain of the LFO using delay,
3467slope and gain. In 'multi' mode the envelope is triggered for every note that
3468is played and in the emulator this is actually a separate LFO per voice, a bit
3469fatter than the original. In 'Mono' mode there is only one LFO that all voices
3470will share and the envelope is triggered in Legato style, ie, only once for
3471a sequence of notes - all have to be released for the envelope to recover.
3472
3473VCO: The original allowed for wavaeform selection to alternate between notes,
3474something that is rather ugly to do with the bristol architecture. This is
3475replaced with a VCO selector where each note will only take the output from
3476one of the two avalable oscillators and gives the ntoes a little more
3477separation. The legato mode works whereby the oscillator selection is only
3478made for the first note in a sequence to give a little more sound consistency.
3479
3480Glide: This is probably the coolest feature of the synth. Since it used an
3481organ divider circuit it was not possible to actually glide from one note to
3482another - there are really only two oscillators in the synth section, not two
3483per voice. In contrast the glide section could glide up or down from a selected
3484amount to the real frequency. Selected from down with suitable values would
3485give a nice 'blue note' effect for example. In Legato mode this is done only
3486for the first keypress rather than all of the since the effect can be a bit
3487over the top if applied to each keystroke in a sequence. At the same time it
3488was possible to Sync the two oscillators, so having only one of them glide
3489and be in sync then without legato this gave a big phasing entrance to each
3490note, a very interesting effect. The Glide has 4 modes:
3491
3492 A. Both oscillators glide up to the target frequency
3493 B. Only oscillator-2 glides up to the target frequency
3494 C. Only oscillator-2 glides down to the target frequency
3495 D. Both oscillators glide down to the target frequency
3496
3497These glide options with different sync and legato lead to some very unique
3498sounds and are emulated here with only minor differences.
3499
3500The features, then notes on the differences to the original:
3501
3502 A. Organ Section
3503
3504 16, 8, 4 and 2 foot harmonic strengths.
3505 Volume.
3506
3507 B. Synth Section
3508
3509 LFO Modulation
3510
3511 Rate - 0.1 to 50Hz approx
3512 Slope - up to 10 seconds
3513 Delay - up to 10 seconds
3514 Gain
3515
3516 Routing selector: VCO, VCF, VCA
3517 Mono/Multi legato mode
3518 Shape - Tri/Ramp/Saw/Square
3519
3520 Oscillator 1
3521
3522 Tuning
3523 Sync 2 to 1
3524 Octave selector
3525
3526 Oscillator 2
3527
3528 Tuning
3529 Octave trill
3530 Octave selector
3531
3532 Waveform Ramp and Square mix
3533 Alternate on/off
3534 Mono/Multi legato mode VCO selection
3535
3536 Glide
3537
3538 Amount up or down from true frequency
3539 Speed of glide
3540 Mono/Multi legato mode
3541 Direction A, B, C, D
3542
3543 Filter
3544
3545 Cutoff frequency
3546 Resonance
3547 Envelope tracking -ve to +ve
3548 Pedal tracking on/off
3549
3550 Envelope
3551
3552 Attack
3553 Decay
3554 Sustain
3555 Release
3556
3557 Gain
3558
3559 C. String Section
3560
3561 16' 8' mix
3562 Subharmonic gain
3563 Attack
3564 Release
3565
3566 Volume
3567
3568Diverse liberties were taken with the reproduction, these are manageable from
3569the options panel by selecting the button next to the keyboard. This opens up
3570a graphic of a PCB, mostly done for humorous effect as it not in the least bit
3571representative of the actual hardware. Here there are a number of surface
3572mounted controllers. These are as below but may change by release:
3573
3574 P1 Master volume
3575
3576 P2 Organ pan
3577 P3 Organ waveform distorts
3578 P4 Organ spacialisation
3579 P5 Organ mod level
3580 J1 Organ key grooming
3581 P6 Organ tuning (currently inactive *)
3582
3583 P7 Synth pan
3584 P8 Synth tuning
3585 P9 Synth osc1 harmonics
3586 P10 Synth osc2 harmonics
3587 J2 Synth velocity sensitivity
3588 J3 Synth filter type
3589 P11 Synth filter tracking
3590
3591 P12 String pan
3592 P13 String harmonics
3593 P14 String spacialisation
3594 P15 String mod level
3595 P16 String waveform distorts
3596
3597*: To make the organ tunable the keymap file has to be removed.
3598
3599Master (P1) volume affects both layers simultaneously and each layer can be
3600panned (P2/P7) and tuned (P8) separately to give phasing and spacialisation.
3601The synth layer has the default frequency map of equal temperament however the
3602organ section uses a 2MHz divider frequency map that is a few cents out for
3603each key. The Trilogy actually has this map for both layers and that can easily
3604be done with the emulator, details on request.
3605
3606It is currently not possible to retune the organ divider circuit, it has a
3607private microtonal mapping to emulate the few percent anomalies of the divider
3608circuit and the frequencies are predefined. The pot is still visible in P6 and
3609can be activated by removing the related microtonal mapping file, details from
3610the author on request.
3611
3612Diverse liberties were taken with the Organ section since the original only
3613produced 4 pure (infinite bandwidth) square waves that were mixed together,
3614an overly weak result. The emulator adds a waveform distort (P3), an notched
3615control that produces a pure sine wave at centre point. Going down it will
3616generate gradually increasing 3rd and 5th harmonics to give it a squarey wave
3617with a distinct hammond tone. The distortion actually came from the B3 emulator
3618which models the distort on the shape of the hammond tonewheels themselves.
3619Going up from centre point will produce gradually sharper sawtooth waves using
3620a different phase distortion.
3621
3622Organ spacialisation (P4) will separate out the 4 harmonics to give them
3623slightly different left and right positions to fatten out the sound. This works
3624in conjunction with the mod level (P5) where one of the stereo components of
3625each wave is modified by the LFO to give phasing changes up to vibrato.
3626
3627The organ key grooming (J1) will either give a groomed wave to remove any
3628audible clicks from the key on and off events or when selected will produce
3629something akin to a percussive ping for the start of the note.
3630
3631The result for the organ section is that it can produce some quite nice sounds
3632reminiscent of the farfisa range to not quite hammond, either way far more
3633useful than the flat, honking square waves. The original sound can be made by
3634waveform to a quarter turn or less, spacialisation and mod to zero, key
3635grooming off.
3636
3637The synth has 5 modifications at the first release. The oscillator harmonics
3638can be fattened at the top or bottom using P9 and P10, one control for each
3639oscillator, low is more bass, high is more treble. Some of the additional
3640harmonics will be automatically detuned a little to fatten out the sound as a
3641function of the -detune parameter defaulting to 100.
3642
3643The envelope can have its velocity sensitively to the filter enabled or disabled
3644(J2) and the filter type can be a light weight filter for a thinner sound but at
3645far lower CPU load (J3).
3646
3647The filter keyboard tracking is configurable (P11), this was outside of the spec
3648of the Trilogy however it was implemented here to correct the keyboard tracking
3649of the filter for all the emulations and the filter should now be playable.
3650The envelope touch will affect this depending on J2 since velocity affects the
3651cut off frequency and that is noticeable when playing the filter. This jumper
3652is there so that the envelope does not adversely affect tuning but can still be
3653used to have the filter open up with velocity if desired.
3654
3655The mod application is different from the original. It had a three way selector
3656for routing the LFO to either VCO, VCA or VCF but only a single route. This
3657emulation uses a continuous notched control where full off is VCO only, notch
3658is VCF only and full on is VCA however the intermidiate positions will route
3659proportional amounts to two components.
3660
3661The LFO has more options (Ramp and Saw) than the original (Tri and Square).
3662
3663The extra options are saved with each memory however they are only loaded at
3664initialisation and when the 'Load' button is double-clicked. This allows you to
3665have them as global settings or per memory as desired. The MemUp and MemDown
3666will not load the options, only the main settings.
3667
3668VCO mod routing is a little bit arbitrary in this first release however I could
3669not find details of the actual implementation. The VCO mod routing only goes
3670to Osc-1 which also takes mod from the joystick downward motion. Mod routing
3671to Osc-2 only happens if 'trill' is selected. This seemed to give the most
3672flexibility, directing the LFO to VCF/VCA and controlling vibrato from the
3673stick, then having Osc-2 separate so that it can be modified and sync'ed to
3674give some interesting phasing.
3675
3676As of the first release there are possibly some issues with the oscillator
3677Sync selector, it is perhaps a bit noisy with a high content of square wave.
3678Also, there are a couple of minor improvements that could be made to the
3679legato features but they will be done in a future release. They regard how
3680the glide is applied to the first or all in a sequence of notes.
3681
3682The joystick does not always pick up correctly however it is largely for
3683presentation, doing actual work you would use a real joystick or just use the
3684modwheel (the stick generates and tracks continuous controller 1 - mod). The
3685modwheel tracking is also a bit odd but reflects the original architecture -
3686at midpoint on the wheel there is no net modulation, going down affects VCO
3687in increasing amounts and going up from mid affect the VCF. The control feels
3688like it should be notched however generally that is not the case with mod
3689wheels.
3690
3691A few notes are required on oscillator sync since by default it will seem to
3692be quite noisy. The original could only product a single waveform at a single
3693frequency at any one time. Several emulators, including this one, use a bitone
3694oscillator which generates complex waveforms. The Bristol Bitone can generate
3695up to 4 waveforms simultaneously at different levels for 5 different harmonics
3696and the consequent output is very rich, the waves can be slightly detuned,
3697the pulse output can be PW modulated. As with all the bristol oscillators that
3698support sync, the sync pulse is extracted as a postive leading zero crossing.
3699Unfortunately if the complex bitone output is used as input to sync another
3700oscillator then the result is far too many zero crossings to extract a good
3701sync. For the time being you will have to simplify the sync source to get a
3702good synchronised output which itself may be complex wave. A future release
3703will add a sync signal from the bitone which will be a single harmonic at the
3704base frequency and allow both syncing and synchronised waveform outputs to be
3705arbitrary. For the Trilogy this simplification of the sync waveform is done
3706automatically by the Sync switch, this means the synchronised output sounds
3707correct but the overall waveform may be simpler.
3708
3709
3710
3711
3712 CRUMAR STRATUS
3713 --------------
3714
3715This unit is a hybrid synth/organ combo, an early polyphonic synth using an
3716organ divider circuit rather than independent VCO and having a set of filters
3717and envelope for the synth sounds, most manufacturers came out with similar
3718designs. The organ section was generally regarded as pretty bad here, there
3719were just five controls, four used for the volume of 16, 8, 4 and 2 foot
3720harmonics and a fifth for overall organ volume. The synth section had 6 voices
3721and some quite neat little features for a glide circuitry and legato playing
3722modes.
3723
3724The emulator consists of two totally separate layers, one emulating the organ
3725circuitry and another the synth. The organ has maximum available polyphony as
3726the algorithm is quite lightweight even though diverse liberties have been
3727taken to beef up the sound. The synth section is limited to 6 voices unless
3728otherwise specified at run time.
3729
3730The legato playing modes affects three sections, the LFO modulation, VCO
3731selection and glide:
3732
3733LFO: this mod has a basic envelope to control the gain of the LFO using delay,
3734slope and gain. In 'multi' mode the envelope is triggered for every note that
3735is played and in the emulator this is actually a separate LFO per voice, a bit
3736fatter than the original. In 'Mono' mode there is only one LFO that all voices
3737will share and the envelope is triggered in Legato style, ie, only once for
3738a sequence of notes - all have to be released for the envelope to recover.
3739
3740VCO: The original allowed for wavaeform selection to alternate between notes,
3741something that is rather ugly to do with the bristol architecture. This is
3742replaced with a VCO selector where each note will only take the output from
3743one of the two avalable oscillators and gives the ntoes a little more
3744separation. The legato mode works whereby the oscillator selection is only
3745made for the first note in a sequence to give a little more sound consistency.
3746
3747Glide: This is probably the coolest feature of the synth. Since it used an
3748organ divider circuit it was not possible to actually glide from one note to
3749another - there are really only two oscillators in the synth section, not two
3750per voice. In contrast the glide section could glide up or down from a selected
3751amount to the real frequency. Selected from down with suitable values would
3752give a nice 'blue note' effect for example. In Legato mode this is done only
3753for the first keypress rather than all of the since the effect can be a bit
3754over the top if applied to each keystroke in a sequence. At the same time it
3755was possible to Sync the two oscillators, so having only one of them glide
3756and be in sync then without legato this gave a big phasing entrance to each
3757note, a very interesting effect. The Glide has 4 modes:
3758
3759 A. Both oscillators glide up to the target frequency
3760 B. Only oscillator-2 glides up to the target frequency
3761 C. Only oscillator-2 glides down to the target frequency
3762 D. Both oscillators glide down to the target frequency
3763
3764These glide options with different sync and legato lead to some very unique
3765sounds and are emulated here with only minor differences.
3766
3767The features, then notes on the differences to the original:
3768
3769 A. Organ Section
3770
3771 16, 8, 4 and 2 foot harmonic strengths.
3772 Volume.
3773
3774 B. Synth Section
3775
3776 LFO Modulation
3777
3778 Rate - 0.1 to 50Hz approx
3779 Slope - up to 10 seconds
3780 Delay - up to 10 seconds
3781 Gain
3782
3783 Routing selector: VCO, VCF, VCA
3784 Mono/Multi legato mode
3785 Shape - Tri/Ramp/Saw/Square
3786
3787 Oscillator 1
3788
3789 Tuning
3790 Sync 2 to 1
3791 Octave selector
3792
3793 Oscillator 2
3794
3795 Tuning
3796 Octave trill
3797 Octave selector
3798
3799 Waveform Ramp and Square mix
3800 Alternate on/off
3801 Mono/Multi legato mode VCO selection
3802
3803 Glide
3804
3805 Amount up or down from true frequency
3806 Speed of glide
3807 Mono/Multi legato mode
3808 Direction A, B, C, D
3809
3810 Filter
3811
3812 Cutoff frequency
3813 Resonance
3814 Envelope tracking -ve to +ve
3815 Pedal tracking on/off
3816
3817 Envelope
3818
3819 Attack
3820 Decay
3821 Sustain
3822 Release
3823
3824 Gain
3825
3826Diverse liberties were taken with the reproduction, these are manageable from
3827the options panel by selecting the button next to the keyboard. This opens up
3828a graphic of a PCB, mostly done for humorous effect as it not in the least bit
3829representative of the actual hardware. Here there are a number of surface
3830mounted controllers. These are as below but may change by release:
3831
3832 P1 Master volume
3833
3834 P2 Organ pan
3835 P3 Organ waveform distorts
3836 P4 Organ spacialisation
3837 P5 Organ mod level
3838 J1 Organ key grooming
3839 P6 Organ tuning (currently inactive *)
3840
3841 P7 Synth pan
3842 P8 Synth tuning
3843 P9 Synth osc1 harmonics
3844 P10 Synth osc2 harmonics
3845 J2 Synth velocity sensitivity
3846 J3 Synth filter type
3847 P11 Synth filter tracking
3848
3849*: To make the organ tunable the keymap file has to be removed.
3850
3851Master (P1) volume affects both layers simultaneously and each layer can be
3852panned (P2/P7) and tuned (P8) separately to give phasing and spacialisation.
3853The synth layer has the default frequency map of equal temperament however the
3854organ section uses a 2MHz divider frequency map that is a few cents out for
3855each key. The Stratus actually has this map for both layers and that can easily
3856be done with the emulator, details on request.
3857
3858It is currently not possible to retune the organ divider circuit, it has a
3859private microtonal mapping to emulate the few percent anomalies of the divider
3860circuit and the frequencies are predefined. The pot is still visible in P6 and
3861can be activated by removing the related microtonal mapping file, details from
3862the author on request.
3863
3864Diverse liberties were taken with the Organ section since the original only
3865produced 4 pure (infinite bandwidth) square waves that were mixed together,
3866an overly weak result. The emulator adds a waveform distort (P3), an notched
3867control that produces a pure sine wave at centre point. Going down it will
3868generate gradually increasing 3rd and 5th harmonics to give it a squarey wave
3869with a distinct hammond tone. The distortion actually came from the B3 emulator
3870which models the distort on the shape of the hammond tonewheels themselves.
3871Going up from centre point will produce gradually sharper sawtooth waves using
3872a different phase distortion.
3873
3874Organ spacialisation (P4) will separate out the 4 harmonics to give them
3875slightly different left and right positions to fatten out the sound. This works
3876in conjunction with the mod level (P5) where one of the stereo components of
3877each wave is modified by the LFO to give phasing changes up to vibrato.
3878
3879The organ key grooming (J1) will either give a groomed wave to remove any
3880audible clicks from the key on and off events or when selected will produce
3881something akin to a percussive ping for the start of the note.
3882
3883The result for the organ section is that it can produce some quite nice sounds
3884reminiscent of the farfisa range to not quite hammond, either way far more
3885useful than the flat, honking square waves. The original sound can be made by
3886waveform to a quarter turn or less, spacialisation and mod to zero, key
3887grooming off.
3888
3889The synth has 5 modifications at the first release. The oscillator harmonics
3890can be fattened at the top or bottom using P9 and P10, one control for each
3891oscillator, low is more bass, high is more treble. Some of the additional
3892harmonics will be automatically detuned a little to fatten out the sound as a
3893function of the -detune parameter defaulting to 100.
3894
3895The envelope can have its velocity sensitively to the filter enabled or disabled
3896(J2) and the filter type can be a light weight filter for a thinner sound but at
3897far lower CPU load (J3).
3898
3899The filter keyboard tracking is configurable (P11), this was outside of the spec
3900of the Stratus however it was implemented here to correct the keyboard tracking
3901of the filter for all the emulations and the filter should now be playable.
3902The envelope touch will affect this depending on J2 since velocity affects the
3903cut off frequency and that is noticeable when playing the filter. This jumper
3904is there so that the envelope does not adversely affect tuning but can still be
3905used to have the filter open up with velocity if desired.
3906
3907The mod application is different from the original. It had a three way selector
3908for routing the LFO to either VCO, VCA or VCF but only a single route. This
3909emulation uses a continuous notched control where full off is VCO only, notch
3910is VCF only and full on is VCA however the intermidiate positions will route
3911proportional amounts to two components.
3912
3913The LFO has more options (Ramp and Saw) than the original (Tri and Square).
3914
3915The extra options are saved with each memory however they are only loaded at
3916initialisation and when the 'Load' button is double-clicked. This allows you to
3917have them as global settings or per memory as desired. The MemUp and MemDown
3918will not load the options, only the main settings.
3919
3920VCO mod routing is a little bit arbitrary in this first release however I could
3921not find details of the actual implementation. The VCO mod routing only goes
3922to Osc-1 which also takes mod from the joystick downward motion. Mod routing
3923to Osc-2 only happens if 'trill' is selected. This seemed to give the most
3924flexibility, directing the LFO to VCF/VCA and controlling vibrato from the
3925stick, then having Osc-2 separate so that it can be modified and sync'ed to
3926give some interesting phasing.
3927
3928As of the first release there are possibly some issues with the oscillator
3929Sync selector, it is perhaps a bit noisy with a high content of square wave.
3930Also, there are a couple of minor improvements that could be made to the
3931legato features but they will be done in a future release. They regard how
3932the glide is applied to the first or all in a sequence of notes.
3933
3934The joystick does not always pick up correctly however it is largely for
3935presentation, doing actual work you would use a real joystick or just use the
3936modwheel (the stick generates and tracks continuous controller 1 - mod). The
3937modwheel tracking is also a bit odd but reflects the original architecture -
3938at midpoint on the wheel there is no net modulation, going down affects VCO
3939in increasing amounts and going up from mid affect the VCF. The control feels
3940like it should be notched however generally that is not the case with mod
3941wheels.
3942
3943A few notes are required on oscillator sync since by default it will seem to
3944be quite noisy. The original could only product a single waveform at a single
3945frequency at any one time. Several emulators, including this one, use a bitone
3946oscillator which generates complex waveforms. The Bristol Bitone can generate
3947up to 4 waveforms simultaneously at different levels for 5 different harmonics
3948and the consequent output is very rich, the waves can be slightly detuned,
3949the pulse output can be PW modulated. As with all the bristol oscillators that
3950support sync, the sync pulse is extracted as a postive leading zero crossing.
3951Unfortunately if the complex bitone output is used as input to sync another
3952oscillator then the result is far too many zero crossings to extract a good
3953sync. For the time being you will have to simplify the sync source to get a
3954good synchronised output which itself may be complex wave. A future release
3955will add a sync signal from the bitone which will be a single harmonic at the
3956base frequency and allow both syncing and synchronised waveform outputs to be
3957arbitrary. For the Stratus this simplification of the sync waveform is done
3958automatically by the Sync switch, this means the synchronised output sounds
3959correct but the overall waveform may be simpler.
3960
3961
3962
3963
3964 KORG POLY 800
3965 -------------
3966
3967This is a low cost hybrid synth, somewhere between the Korg PolySix and their
3968Mono/Poly in that is polyphonic but only has one filter rather than one per
3969voice that came with the PolySix. It may have also used organ divider circuits
3970rather than individual oscillators - it did not have glide as a feature which
3971would be indicative of a divider circuit.
3972
3973It featured 8 oscillators that could be applied as either 4 voices with dual
3974osc or 8 voices with a single osc. The architecture was verging on the
3975interesting since each oscillator was fead into an individual envelope generator
3976(described below) and then summed into the single filter, the filter having
3977another envelope generator, 9 in total. This lead to cost reduction over having
3978a filter per voice however the single filter leads to breathing, also discussed
3979below. The envelopes were digitally generated by an on-board CPU.
3980
3981The control panel has a volume, global tuning control and a 'Bend' control
3982that governs the depth of the pitch bend from the joystick and the overall
3983amount of DCO modulation applied by the joystick. There is no sequencer in
3984this emulation largely because there are far better options now available than
3985this had but also due to a shortage of onscreen realestate.
3986
3987The Poly, Chord and Hold keys are emulated, hold being a sustain key. The
3988Chord relearn function works follows:
3989
3990 Press the Hold key
3991 Press the Chord key with 2 seconds
3992 Press the notes on the keyboard (*)
3993 Press the Chord key again
3994
3995After that the single chord can be played from a single note as a monophonic
3996instrument. The Chord is saved individually with each memory.
3997* Note that the chord is only saved if (a) it was played from the GUI keyboard
3998or (b) the GUI was linked up to any MIDI device as well as the engine. The
3999reason is that the GUI maintains memories and so if a chord is played on your
4000actual keyboard then both the engine and the GUI needs a copy, the engine to
4001be able to play the notes and the GUI to be able to save them.
4002
4003The keypanel should function very similar to the original. There is a Prog
4004button that selects between Program selection or Parameter selection and an
4005LED should show where the action is. There is the telephone keyboard to enter
4006program or parameters numbers and an up/down selector for parameter value.
4007The Bank/Hold selector also works, it fixes the bank number so programs can
4008be recalled from a single bank with a single button press. The Write function
4009is as per the original - Press Write, then two digits to save a memory.
4010
4011The front panel consists of a data entry panel and a silkscreen of the parameter
4012numbers (this silkscreen is active in the emulation). Fifty parameters are
4013available from the original instrument:
4014
4015 DE 11 DCO1 Octave transposition +2 octaves
4016 DE 12 DCO1 Waveform Square or Ramp
4017 DE 13 DCO1 16' harmonic
4018 DE 14 DCO1 8' harmonic
4019 DE 15 DCO1 4' harmonic
4020 DE 16 DCO1 2' harmonic
4021 DE 17 DCO1 level
4022
4023 DE 18 DCO Double (4 voice) or Single (8 voice)
4024
4025 DE 21 DCO2 Octave transposition +2 octaves
4026 DE 22 DCO2 Waveform Square or Ramp
4027 DE 23 DCO2 16' harmonic
4028 DE 24 DCO2 8' harmonic
4029 DE 25 DCO2 4' harmonic
4030 DE 26 DCO2 2' harmonic
4031 DE 27 DCO2 level
4032 DE 31 DCO2 semitone transpose
4033 DE 32 DCO2 detune
4034
4035 DE 33 Noise level
4036
4037 DE 41 Filter cutoff frequency
4038 DE 42 Filter Resonance
4039 DE 43 Filter Keyboard tracking off/half/full
4040 DE 44 Filter Envelope polarity
4041 DE 45 Filter Envelope amount
4042 DE 46 Filter Envelope retrigger
4043
4044 DE 48 Chorus On/Off
4045
4046 DE 51 Env-1 DCO1 Attack
4047 DE 52 Env-1 DCO1 Decay
4048 DE 53 Env-1 DCO1 Breakpoint
4049 DE 54 Env-1 DCO1 Slope
4050 DE 55 Env-1 DCO1 Sustain
4051 DE 56 Env-1 DCO1 Release
4052
4053 DE 61 Env-2 DCO2 Attack
4054 DE 62 Env-2 DCO2 Decay
4055 DE 63 Env-2 DCO2 Breakpoint
4056 DE 64 Env-2 DCO2 Slope
4057 DE 65 Env-2 DCO2 Sustain
4058 DE 66 Env-2 DCO2 Release
4059
4060 DE 71 Env-3 Filter Attack
4061 DE 72 Env-3 Filter Decay
4062 DE 73 Env-3 Filter Breakpoint
4063 DE 74 Env-3 Filter Slope
4064 DE 75 Env-3 Filter Sustain
4065 DE 76 Env-3 Filter Release
4066
4067 DE 81 Mod LFO Frequency
4068 DE 82 Mod Delay
4069 DE 83 Mod DCO
4070 DE 84 Mod VCF
4071
4072 DE 86 Midi channel
4073 DE 87 Midi program change enable
4074 DE 88 Midi OMNI
4075
4076Of these 25 pararmeters, the emulation has changed 88 to be OMNI mode rather
4077than the original sequence clock as internal or external. This is because the
4078sequencer function was dropped as explained above.
4079
4080Additional to the original many of the controls which are depicted as on/off
4081are actually continuous. For example, the waveform appears to be either square
4082or ramp. The emulator allows you to use the up/down Value keys to reproduce
4083this however if you use the potentiometer then you can gradually move from one
4084wave to the next. The different harmonics are also not on/off, you can mix
4085each of them together with different amounts and if you configure a mixture
4086of waveforms and a bit of detune the sound should widen due to addition of a
4087bit of phasing within the actual oscillator.
4088
4089The envelope generators are not typical ADSR. There is an initial attack from
4090zero to max gain then decay to a 'Breakpoint'. When this has been reached then
4091the 'Slope' parameter will take the signal to the Sustain level, then finally
4092the release rate. The extra step of breakpoint and slope give plenty of extra
4093flexibility to try and adjust for the loss of a filter per voice and the
4094emulation has a linear step which should be the same as the original. The
4095ninth envelope is applied to the single filter and also as the envelope for
4096the noise signal level.
4097
4098The single filter always responded to the highest note on the keyboard. This
4099gives a weaker overall sound and if playing with two hands then there is a
4100noticible effect with keytracking - left hand held chords will cause filter
4101breathing as the right hand plays solos and the keyboard tracking changes
4102from high to low octaves. Note that the emulator will implement a single
4103filter if you select DE 46 filter envelope retrigger to be single trigger, it
4104will be played legato style. If multiple triggers are selected then the
4105emulator will produce a filter and envelope for each voice.
4106
4107Bristol adds a number of extra parameters to the emulator that are not
4108available from the mouse on the silkscreen and were not a part of the design
4109of the poly800. You have to select Prog such that the LED is lit next to the
4110Param display, then select the two digit parameter from the telephone keyboard:
4111
4112 DE 28 DCO Sync 2 to 1
4113 DE 34 DCO-1 PW
4114 DE 35 DCO-1 PWM
4115 DE 36 DCO-2 PW
4116 DE 37 DCO-2 PWM
4117 DE 38 DCO temperature sensitivity
4118 DE 67 DCO Glide
4119
4120 DE 85 Mod - Uni/Multi per voice or globally
4121
4122 DE 57 Envelope Touch response
4123
4124 DE 47 Chorus Parameter 0
4125 DE 58 Chorus Parameter 1
4126 DE 68 Chorus Parameter 2
4127 DE 78 Chorus Parameter 3
4128
4129If DataEntry 28 is selected for oscillator sync then LFO MOD to DCO-1 is no
4130longer applied, it only goes to DCO-2. This allows for the interesting sync
4131modulated slow vibrato of DCO-2. The LFO mod is still applied via the joystick.
4132
4133DE 38 global detune will apply both temperature sensitivity to each oscillator
4134but also fatten out the harmonics by detuning them independently. It is only
4135calculated at 'note on' which can be misleading - it has no effect on existing
4136notes which is intentional if misleading.
4137
4138DE 57 is a bitmask for the three envelopes to define which ones will give a
4139response to velocity with a default to '3' for velocity tracking oscillator
4140gain:
4141
4142 value DEG1 DEG2 DEG3
4143 DCO1 DCO2 FILT
4144
4145 0 - - -
4146 1 V - -
4147 2 - V -
4148 3 V V -
4149 4 - - V
4150 5 V - V
4151 6 - V V
4152 7 V V V
4153
4154This gives some interesting velocity tracking capabilities where just one osc
4155can track velocity to introduce harmonic content keeping the filter at a fixed
4156cutoff frequence. Having a bit of detune applied globally and locally will keep
4157the sound reasonably fat for each oscillator.
4158
4159The filter envelope does not track velocity for any of the distributed voices,
4160this was intentional since when using high resonance it is not desirable that
4161the filter cutoff changes with velocity, it tends to be inconsistently
4162disonant.
4163
4164If you want to use this synth with controller mappings then map the value
4165entry pot to your easiest to find rotary, then click the mouse on the membrane
4166switch to select which parameter you want to adjust with that control each time.
4167The emulator is naturally not limited to just 4/8 voices, you can request more
4168in which case single oscillator will give you the requested number of voices
4169and double will give you half that amount.
4170
4171The Bristol Poly-800 is dedicated to Mark.
4172
4173
4174
4175
4176 Baumann BME-700
4177 ---------------
4178
4179This unusual German synth had a build volume of about 500 units and only one
4180useful source of information could be found on it: a report on repair work for
4181one of the few existing examples at www.bluesynths.com. The BME systems were
4182hand built and judging by some reports on build quality may have been sold in
4183kit form. The unit was produced in the mid 1970's.
4184
4185The synth has a very interesting design, somewhat reminiscent of the Moog Sonic
4186and Explorer synths. It has two modulating LFO with fairly high top frequency,
4187two filter and two envelopes. The envelopes are either AR or ASR but they can
4188be mixed together to generate amongst other features an ADSR, very innovative.
4189There is only one oscillator but the sound is fattened out by the use of two
4190parallel filters, one acting as a pure resonator and the other as a full VCF.
4191
4192The synth has been left with a minimum of overhead. There are just 8 memory
4193locations on the front panel with Load, Save and Increment buttons and one
4194panel of options to adjust a few parameters on the oscillator and filters. It
4195is possible to get extra memories by loading banks with -load: if you request
4196starting in memory #21 the emulator will stuff 20 into the bank and 1 into the
4197memory location. There is no apparant midi channel selector, use -channel <n>
4198and then stay on it. This could have been put into the options panel however
4199having midi channel in a memory is generally a bad idea.
4200
4201 A. MOD
4202
4203 Two LFO:
4204
4205 frequency from 0.1 to 100 Hz
4206 Triangle and Square wave outputs
4207
4208 Mix control
4209
4210 Mod-1/2 into the VCO FM
4211 Env-1/Mod-2 into the VCO FM
4212
4213 B. Oscillator
4214
4215 Single VCO
4216
4217 Glide 0 to 10s, on/off.
4218 PW Man: 5 to 50% duty cycle
4219 Auto depth:
4220
4221 Envelope-1
4222 Mod-1, Mod-1/2, Tri/Square
4223
4224 Vibrato depth
4225 Tuning
4226 8', 4', 16' transposition
4227
4228 Shape
4229
4230 continuous control from Square to Tri wave.
4231
4232 Mix of noise or VCO output
4233
4234 C. Res Filter
4235
4236 Sharp (24db/Oct), Flat (12dB/Oct)
4237 5 frequency switches
4238
4239 D. Envelopes
4240
4241 Two envelopes
4242
4243 Rise time
4244 Fall Time
4245 AR/ASR selector
4246
4247 Two independent mixes of Env, for VCF and VCA.
4248
4249 E. Filter
4250
4251 Frequency
4252 Resonance
4253 Env/Mod selector
4254
4255 Modulation
4256
4257 KBD tracking
4258 Mod-1 or Mod-2, Tri/Square
4259
4260 F. Amplifier
4261
4262 Mix resonator/filter.
4263 Volume
4264
4265 Mod depth
4266
4267 Mod-1 or Mod-2, Tri/Square
4268
4269The oscillator is implemented as a non-resampling signal generator, this means
4270it uses heuristics to estimate the wave at any given time. The harmonic content
4271is a little thin and although the generation method seems to be correct in how
4272it interprets signal ramps and drains from an analogue circuit this is one area
4273of improvement in the emulator. There are options to produce multiple waveforms
4274described below.
4275
4276The resonant filter is implemented with a single Houvilainen and actually only
4277runs at 24dB/Oct. There are controls for remixing the different taps, a form
4278of feedforward and when in 'Flat' mod there is more remixing of the poles, this
4279does generate a slower roll off but gives the signal a bit more warmth than a
4280pure 12dB/Oct would.
4281
4282
4283There is a selector in the Memory section to access some options:
4284
4285 G. Options
4286
4287 LFO
4288
4289 Synchronise wave to key on events
4290 Multi LFO (per voice).
4291
4292 Oscillator
4293
4294 Detune (temperature sensitivity)
4295 Multi - remix 8' with 16' or 4'.
4296
4297 Noise
4298
4299 Multi Noise (per voice).
4300 White/Pink
4301 Pink Filter
4302
4303 ResFilter
4304
4305 Sharp Resonance/Remix
4306 Flat Resonance/Remix
4307
4308 Envelope
4309
4310 Velocity Sensitive
4311 Rezero for note on
4312 Gain
4313
4314 Filter
4315
4316 Remix
4317 KBD tracking depth
4318
4319The emulator probably gives the best results with the following:
4320
4321startBristol -bme700 -mono -hnp -retrig -channel 1
4322
4323This gives a monophonic emulation with high note preference and multiple
4324triggers.
4325
4326The options from section G are only loaded under two circumstances: at system
4327start from the first selected memory location and if the Load button is given
4328a DoubleClick. All other memory load functions will inherrit the settings that
4329are currently active.
4330
4331
4332
4333
4334 Bristol BassMaker
4335 -----------------
4336
4337The BassMaker is not actually an emulator, it is a bespoke sequencer design but
4338based on the capabilities of some of the early analogue sequencers such as the
4339Korg SQ-10. Supplying this probably leaves bristol open to a lot of feature
4340requests for sequencer functionaliity and it is stated here that the BassMaker
4341is supposed to be simple so excess functionality will probably be declined as
4342there are plenty of other sequencing applications that can provide a richer
4343feature set.
4344
4345The main page gives access to a screen of controls for 16 steps and a total of
43464 pages are available for a total of 64 steps. The pages are named 'A' through
4347'D'. Each step has 5 options:
4348
4349 Note: one octave of note selection
4350 Transpose: +/- one octave transposition of the note.
4351 Volume: MIDI note velocity
4352 Controller: MIDI modulation, discussed further below
4353 Triggers: Note On/Off enablers
4354
4355The trigger button gives 4 options indicated by the LED:
4356
4357 off: note on/off are sent
4358 red: only send note_on
4359 green: only send note_off
4360 yellow: do not send note on/off
4361
4362The 'Controllers' setting has multiple functions which can be selected from
4363the menu as explained below. The options available are as follows:
4364
4365 Send semitone tuning
4366
4367 Send glide rate
4368
4369 Send modwheel
4370
4371 Send expression pedal (controller value)
4372
4373 Send Note: the controller will be 12 discrete steps as per the 'Note'
4374 setting and this note will be sent on the Secondary MIDI channel.
4375
4376The semitone tuning and glide work for the majority of the emulations. Some do
4377not support fine tune controls (Vox, Hammond, others). If you are missing these
4378capabilities for specific emulators raise a change request on Sourceforge.net.
4379
4380At the top of the window there is a panel to manage the sequencer. It has the
4381following functions:
4382
4383 Speed: step rate through the notes
4384 DutyCycle: ratio of note-on to note-off
4385
4386 Start/Pause
4387 Stop: stop and return to first step/page
4388
4389 Direction:
4390 Up
4391 Down
4392 Up/Down
4393 Random
4394
4395 Select: which of the pages to include in the sequence.
4396 Edit: which page is currently displayed to be edited.
4397
4398 Memory:
4399 0..9 key entry buttons, 1000 memories available
4400 Load
4401 Save: doubleclick to save current sequence
4402
4403 Menu Panel
4404 Up, Down menu
4405 Function (return to previous level)
4406 Enter: enter submenu or enter value if in submenu
4407
4408The menu consists of several tables, these can be stepped through using the Up
4409and Down arrows to move through the menu and the 'Enter' arrow to select a sub
4410menu or activate any option. The 'Fn' button returns one level:
4411
4412 Memory:
4413
4414 Find next free memory upwards
4415 Find next memory upwards
4416 Find next memory downwards
4417
4418 Copy:
4419
4420 Copy current edit page to 'A', 'B', 'C' or 'D'.
4421
4422 Control - Set the control value to send:
4423
4424 semitone tuning
4425 glide rate
4426 modwheel
4427 expression pedal (controller value)
4428 note events
4429
4430 First midi channel
4431
4432 Primary midi channel for note events
4433
4434 Second midi channel
4435
4436 Secondary midi channel when 'Control' configured to 'Note' events.
4437
4438 Global Transpose
4439
4440 Transpose the whole sequence up or down 12 semitones
4441
4442 Clear - configure default value for all of the:
4443
4444 Notes to zero
4445 Transpose to zero (midpoint)
4446 Volume to 0.8
4447 Control to midpoint
4448 Triggers to on/off
4449
4450As of the first release in 0.30.8 large parts of the Controllers functionality
4451was only lightly tested. If you do not get the results you anticipate you may
4452require a fix.
4453
4454
4455
4456
4457 Bristol SID
4458 -----------
4459
4460In release 0.40 bristol introduced a piece of code that emulated the Commodore
4461C64 6581 SID chip. The interface uses byte settings of the 31 chip registers to
4462be close to the original plus some floating point IO for extracting the audio
4463signal and configuring some analogue parameters and the 'softSID' is clocked
4464by the sample extraction process.
4465
4466The chip uses integer maths and logic for the oscillators, ring mod, sync and
4467envelopes and emulates the analogue components of the 6581 with floating point
4468code, for the filter and S/N generation.
4469
4470The oscillators will run as per the original using a single phase accumulator
4471and 16 bit frequency space. All the waveforms are extracted logically from the
4472ramp waveform generated by the phase accumulation. Sync and RingMod are also
4473extracted with the same methods. The noise generation is exor/add as per the
4474original however the noise signal will not degenerate when mixing waveforms.
4475The output waves are ANDed together. The bristol control register has an option
4476for Multi waveforms and when selected each oscillator will have its own phase
4477accumulator, can have a detune applied and will be mixed by summation rather
4478than using an AND function.
4479
4480The envelope is an 8 bit up/down counter with a single gate bit. All the 4 bit
4481parameters give rates taken from the chip specifications including the slightly
4482exponential decay and release. Attack is a linear function and the sustain level
4483can only be decreased when active as the counter also refuses to count back up
4484when passed its peak.
4485
4486The filter implements a 12dB/Octave multimode chamberlain filter providing LP,
4487BP and HP signals. This is not the best filter in the world however neither was
4488the original. An additional 24dB/Octave LP filter has been added, optionally
4489available and with feedforward to provide 12/18dB signals. Between them the
4490output can be quite rich.
4491
4492The emulator provides some control over the 'analogue' section. The S/N ratio
4493can be configured from inaudible (just used to prevent denormal of the filter)
4494up to irritating levels. Oscillator leakage is configurable from none up to
4495audible levels and the oscillator detune is configurable in cents although
4496this is a digital parameter and was not a part of the original.
4497
4498Voice-3 provides an 8 bit output of its oscillator and envelope via the normal
4499output registers and the otherwise unused X and Y Analogue registers contain
4500the Voice-1 and Voice-2 oscillator output.
4501
4502The bristol -sid emulator uses two softSID, one generating three audio voices
4503and a second one providing modulation signals by sampling the voice-3 osc and
4504env outputs and also by configuring voice-1 to generate noise to the output,
4505resampling this noise and gating it from voice-3 to get sample and hold. This
4506would have been possible with the original as well if the output signal were
4507suitably coupled back on to one of the X/Y_Analogue inputs.
4508
4509The emulator has several key assignment modes. The emulator is always just
4510monophonic but uses internal logic to assign voices. It can be played as a big
4511mono synth with three voices/oscillators, polyphonically with all voices either
4512sounding the same or optionally configured individually, and as of this release
4513a single arpeggiating mode - Poly-3. Poly-3 will assign Voice-1 to the lowest
4514note, voice-3 to the highest note and will arpeggiate Voice-2 through all other
4515keys that are pressed with a very high step rate. This is to provide some of
4516the sounds of the original C64 where fast arpeggiation was used to sounds
4517chords rather than having to use all the voices. This first implementation
4518does not play very well in Poly-3, a subsequent release will probably have a
4519split keyboard option where one half will arpeggiate and the other half will
4520play notes.
4521
4522This is NOT a SID player, that would require large parts of the C64 to also be
4523emulated and there are plenty of SID players already available.
4524
4525Bristol again thanks Andrew Coughlan, here for proposing the implementation of
4526a SID chip which turned out to be a very interesting project.
4527
4528
4529
4530
4531
4532For the sake of being complete, given below is the verbose help output
4533
4534
4535
4536A synthesiser emulation package.
4537
4538 You should start this package with the startBristol script. This script
4539 will start up the bristol synthesiser binaries evaluating the correct
4540 library paths and executable paths. There are emulation, synthesiser,
4541 operational and GUI parameters:
4542
4543 Emulation:
4544
4545 -mini - moog mini
4546 -explorer - moog voyager
4547 -voyager - moog voyager electric blue
4548 -memory - moog memory
4549 -sonic6 - moog sonic 6
4550 -mg1 - moog/realistic mg-1 concertmate
4551 -hammond - hammond module (deprecated, use -b3)
4552 -b3 - hammond B3 (default)
4553 -prophet - sequential circuits prophet-5
4554 -pro52 - sequential circuits prophet-5/fx
4555 -pro10 - sequential circuits prophet-10
4556 -pro1 - sequential circuits pro-one
4557 -rhodes - fender rhodes mark-I stage 73
4558 -rhodesbass - fender rhodes bass piano
4559 -roadrunner - crumar roadrunner electric piano
4560 -bitone - crumar bit 01
4561 -bit99 - crumar bit 99
4562 -bit100 - crumar bit + mods
4563 -stratus - crumar stratus synth/organ combo
4564 -trilogy - crumar trilogy synth/organ/string combo
4565 -obx - oberheim OB-X
4566 -obxa - oberheim OB-Xa
4567 -axxe - arp axxe
4568 -odyssey - arp odyssey
4569 -arp2600 - arp 2600
4570 -solina - arp/solina string ensemble
4571 -polysix - korg polysix
4572 -poly800 - korg poly-800
4573 -monopoly - korg mono/poly
4574 -ms20 - korg ms20 (unfinished: -libtest only)
4575 -vox - vox continental
4576 -voxM2 - vox continental super/300/II
4577 -juno - roland juno-60
4578 -jupiter - roland jupiter-8
4579 -bme700 - baumann bme-700
4580 -bm - bristol bassmaker sequencer
4581 -dx - yamaha dx-7
4582 -cs80 - yamaha cs-80 (unfinished)
4583 -sidney - commodore-64 SID chip synth
4584 -melbourne - commodore-64 SID polyphonic synth (unfinished)
4585 -granular - granular synthesiser (unfinished)
4586 -aks - ems synthi-a (unfinished)
4587 -mixer - 16 track mixer (unfinished: -libtest only)
4588
4589 Synthesiser:
4590
4591 -voices <n> - operate with a total of 'n' voices (32)
4592 -mono - operate with a single voice (-voices 1)
4593 -lnp - low note preference (-mono)
4594 -hnp - high note preference (-mono)
4595 -nnp - no/last note preference (-mono)
4596 -retrig - monophonic note logic legato trigger (-mono)
4597 -lvel - monophonic note logic legato velocity (-mono)
4598 -channel <c> - initial midi channel selected to 'c' (default 1)
4599 -lowkey <n> - minimum MIDI note response (0)
4600 -highkey <n> - maximum MIDI note response (127)
4601 -detune <%> - 'temperature sensitivity' of emulation (0)
4602 -gain <gn> - emulator output signal gain (default 1)
4603 -pwd <s> - pitch wheel depth (2 semitones)
4604 -velocity <v> - MIDI velocity mapping curve (510) (-mvc)
4605 -glide <s> - MIDI glide duration (5)
4606 -emulate <name> - search for the named synth or exit
4607 -register <name> - name used for jack and alsa device regisration
4608 -lwf - emulator lightweight filters
4609 -nwf - emulator default filters
4610 -wwf - emulator welterweight filters
4611 -hwf - emulator heavyweight filters
4612 -blo <h> - maximum # band limited harmonics (31)
4613 -blofraction <f> - band limiting nyquist fraction (0.8)
4614 -scala <file> - read the scala .scl tonal mapping table
4615
4616 User Interface:
4617
4618 -quality <n> - color cache depth (bbp 2..8) (6)
4619 -grayscale <n> - color or BW display (0..5) (0 = color)
4620 -antialias <n> - antialias depth (0..100%) (30)
4621 -aliastype <s> - antialias type (pre/texture/all)
4622 -opacity <n> - opacity of the patch layer 20..100% (50)
4623 -scale <s> - initial windowsize, fs = fullscreen (1.0)
4624 -width <n> - the pixel width of the GUI window
4625 -autozoom - flip between min and max window on Enter/Leave
4626 -raise - disable auto raise on max resize
4627 -lower - disable auto lower on min resize
4628 -rud - constrain rotary tracking to up/down
4629 -pixmap - use the pixmap interface rather than ximage
4630 -dct <ms> - double click timeout (250 ms)
4631 -tracking - disable MIDI keyboard tracking in GUI
4632 -load <m> - load memory number 'm' (default 0)
4633 -import <pathname> - import memory from file into synth
4634 -mbi <m> - master bank index (0)
4635 -activesense <m> - active sense rate (2000 ms)
4636 -ast <m> - active sense timeout (15000 ms)
4637 -mct <m> - midi cycle timeout (50 ms)
4638 -ar|-aspect - ignore emulator requested aspect ratio
4639 -iconify - start with iconified window
4640 -window - toggle switch to enable X11 window interfacen
4641 -cli - enable command line interface
4642 -libtest - gui test option, engine not invoked
4643
4644 Gui keyboard shortcuts:
4645
4646 <Ctrl> 's' - save settings to current memory
4647 <Ctrl> 'l' - (re)load current memory
4648 <Ctrl> 'x' - exchange current with previous memory
4649 <Ctrl> '+' - load next memory
4650 <Ctrl> '-' - load previous memory
4651 <Ctrl> '?' - show emulator help information
4652 <Ctrl> 'h' - show emulator help information
4653 <Ctrl> 'r' - show application readme information
4654 <Ctrl> 'k' - show keyboard shortcuts
4655 <Ctrl> 'p' - screendump to /tmp/<synth>.xpm
4656 <Ctrl> 't' - toggle opacity
4657 <Ctrl> 'o' - decrease opacity of patch layer
4658 <Ctrl> 'O' - increase opacity of patch layer
4659 <Ctrl> 'w' - display warranty
4660 <Ctrl> 'g' - display GPL (copying conditions)
4661 <Shift> '+' - increase window size
4662 <Shift> '-' - decrease window size
4663 <Shift> 'Enter'- toggle window between full screen size
4664 'UpArrow' - controller motion up (shift key accelerator)
4665 'DownArrow' - controller motion down (shift key accelerator)
4666 'RightArrow' - more controller motion up (shift key accelerator)
4667 'LeftArrow' - more controller motion down (shift key accelerator)
4668
4669 Operational:
4670
4671 General:
4672
4673 -engine - don't start engine (connect to existing engine)
4674 -gui - don't start gui (only start engine)
4675 -server - run engine as a permanant server
4676 -daemon - run engine as a detached permanant server
4677 -log - redirect diagnostic to $HOME/.bristol/log
4678 -syslog - redirect diagnostic to syslog
4679 -console - log all messages to console (must be 1st option)
4680 -cache <path> - memory and profile cache location (~/.bristol)
4681 -exec - run all subprocesses in background
4682 -debug <1-16> - debuging level (0)
4683 -readme [-<e>] - show readme [for emulator <e>] to console
4684 -glwf - global lightweight filters - no overrides
4685 -host <h> - connect to engine on host 'h' (localhost)
4686 -port <p> - connect to engine on TCP port 'p' (default 5028)
4687 -quiet - redirect diagnostic output to /dev/null
4688 -gmc - open a MIDI connection to the brighton GUI
4689 -oss - use OSS defaults for audio and MIDI
4690 -alsa - use ALSA defaults for audio and MIDI (default)
4691 -jack - use Jack defaults for audio and MIDI
4692 -jsmuuid <UUID>- jack session unique identifier
4693 -jsmfile <path>- jack session setting path
4694 -jsmd <ms> - jack session file load delay (5000)
4695 -session - disable session management
4696 -jdo - use separate Jack clients for audio and MIDI
4697 -osc - use OSC for control interface (unfinished)
4698 -forward - disable MIDI event forwarding globally
4699 -localforward - disable emulator gui->engine event forwarding
4700 -remoteforward - disable emulator engine->gui event forwarding
4701 -o <filename> - Duplicate raw audio output data to file
4702 -nrp - enable NPR support globally
4703 -enrp - enable NPR/DE support in engine
4704 -gnrp - enable NPR/RP/DE support in GUI
4705 -nrpcc <n> - size of NRP controller table (128)
4706
4707 Audio driver:
4708
4709 -audio [oss|alsa|jack] - audio driver selection (alsa)
4710 -audiodev <dev> - audio device selection
4711 -count <samples> - sample period count (256)
4712 -outgain <gn> - digital output signal gain (default 4)
4713 -ingain <gn> - digital input signal gain (default 4)
4714 -preload <periods> - configure preload buffer count (default 4)
4715 -rate <hz> - sample rate (44100)
4716 -priority <p> - audio RT priority, 0=no realtime (75)
4717 -autoconn - attempt jack port auto-connect
4718 -multi <c> - register 'c' IO channels (jack only)
4719 -migc <f> - multi IO input gain scaling (jack only)
4720 -mogc <f> - multi IO output gain scaling (jack only)
4721
4722 Midi driver:
4723
4724 -midi [oss|[raw]alsa|jack] - midi driver selection (alsa)
4725 -mididev <dev> - midi device selection
4726 -seq - use the ALSA SEQ interface (default)
4727 -mididbg - midi debug-1 enable
4728 -mididbg2 - midi debug-2 enable
4729 -sysid - MIDI SYSEX system identifier
4730
4731 LADI driver (level 1 compliant):
4732
4733 -ladi brighton - only execute LADI in GUI
4734 -ladi bristol - only execute LADI in engine
4735 -ladi <memory> - LADI state memory index (1024)
4736
4737 Audio drivers are PCM/PCM_plug or Jack. Midi drivers are either OSS/ALSA
4738 rawmidi interface, or ALSA SEQ. Multiple GUIs can connect to the single
4739 audio engine which then operates multitimbrally.
4740
4741 The LADI interfaces does not use a state file but a memory in the normal
4742 memory locations. This should typically be outside of the range of the
4743 select buttons for the synth and the default of 1024 is taken for this
4744 reason.
4745
4746 Examples:
4747
4748 startBristol
4749
4750 Print a terse help message.
4751
4752 startBristol -v -h
4753
4754 Hm, if you're reading this you found these switches already.
4755
4756 startBristol -mini
4757
4758 Run a minimoog using ALSA interface for audio and midi seq. This is
4759 equivalent to all the following options:
4760 -mini -alsa -audiodev plughw:0,0 -midi seq -count 256 -preload 8
4761 -port 5028 -voices 32 -channel 1 -rate 44100 -gain 4 -ingain 4
4762
4763 startBristol -alsa -mini
4764
4765 Run a minimoog using ALSA interface for audio and midi. This is
4766 equivalent to all the following options:
4767 -mini -audio alsa -audiodev plughw:0,0 -midi alsa -mididev hw:0
4768 -count 256 -preload 8 -port 5028 -voices 32 -channel 1 -rate 44100
4769
4770 startBristol -explorer -voices 1 -oss
4771
4772 Run a moog explorer as a monophonic instrument, using OSS interface for
4773 audio and midi.
4774
4775 startBristol -prophet -channel 3
4776
4777 Run a prophet-5 using ALSA for audio and midi on channel 3.
4778
4779 startBristol -b3 -count 512 -preload 2
4780
4781 Run a hammond b3 with a buffer size of 512 samples, and preload two
4782 such buffers before going active. Some Live! cards need this larger
4783 buffer size with ALSA drivers.
4784
4785 startBristol -oss -audiodev /dev/dsp1 -vox -voices 8
4786
4787 Run a vox continental using OSS device 1, and default midi device
4788 /dev/midi0. Operate with just 8 voices.
4789
4790 startBristol -b3 -audio alsa -audiodev plughw:0,0 -seq -mididev 128.0
4791
4792 Run a B3 emulation over the ALSA PCM plug interface, using the ALSA
4793 sequencer over client 128, port 0.
4794
4795 startBristol -juno &
4796 startBristol -prophet -channel 2 -engine
4797
4798 Start two synthesisers, a juno and a prophet. Both synthesisers will
4799 will be executed on one engine (multitimbral) with 32 voices between
4800 them. The juno will be on default midi channel (1), and the prophet on
4801 channel 2. Output over the same default ALSA audio device.
4802
4803 startBristol -juno &
4804 startBristol -port 5029 -audio oss -audiodev /dev/dsp1 -mididev /dev/midi1
4805
4806 Start two synthesisers, a juno on the first ALSA soundcard, and a
4807 mini on the second OSS soundcard. Each synth is totally independent
4808 and runs with 32 voice polyphony (looks nice, not been tested).
4809
4810The location of the bristol binaries can be specified in the BRISTOL
4811environment variable. Private memory and MIDI controller mapping files can
4812be found in the directory BRISTOL_CACHE and defaults to $HOME/.bristol
4813
4814Setting the environment variable BRISTOL_LOG_CONSOLE to any value will result
4815in the bristol logging output going to your console window without formatted
4816timestamps
4817
4818Korg Inc. of Japan is the rightful owner of the Korg and Vox trademarks, and
4819the Polysix, Mono/Poly, Poly-800, MS-20 and Continental tradenames. Their own
4820Vintage Collection provides emulations for a selection of their classic
4821synthesiser range, this product is in no manner related to Korg other than
4822giving homage to their great instruments.
4823
4824Bristol is in no manner associated with any of the original manufacturers of
4825any of the emulated instruments. All names and trademarks are property of
4826their respective owners.
4827
4828 author: Nick Copeland
4829 email: nickycopeland@hotmail.com
4830
4831 http://bristol.sourceforge.net
4832
4833