1pcm.!default { 2 type plug # <-- no { here 3 slave.pcm { 4 type multi 5 slaves { 6 a { channels 2 pcm "hw:0,0" } # the real device 7 b { channels 2 pcm "hw:Loopback,0" } # the loopback driver 8 } 9 bindings { 10 0 { slave a channel 0 } 11 1 { slave a channel 1 } 12 2 { slave b channel 0 } 13 3 { slave b channel 1 } 14 } 15 } 16 ttable [ 17 [ 1 0 1 0 ] # left -> a.left, b.left 18 [ 0 1 0 1 ] # right -> a.right, b.right 19 ] 20} 21