ALSA: клонировать звук на две карты

$ aplay -D allcard test.wav 
aplay: main:722: audio open error: Device or resource busy

pcm.my{
  type plug
  route_policy duplicate
  hint{description my show on}
  slave.pcm{
    type multi
    bindings{
      0{slave 0 channel 0}
      1{slave 0 channel 1}
      2{slave 1 channel 0}
      3{slave 1 channel 1}}
    slaves[
      {channels 2 pcm my_ladspa1}
      {channels 2 pcm my_ladspa2}]}}

pcm.my_ladspa1{
  type ladspa
  path /usr/lib/ladspa
  playback_plugins[
    {label bandpass_iir input.controls[10010 19980 4]}#swh center freq, bandwidth, stages 2 poles per stage
  ]
  slave.pcm'plughw:1,7'}

pcm.my_ladspa2{
  type ladspa
  path /usr/lib/ladspa
  playback_plugins[
    {label bandpass_iir input.controls[60 80 4]}#swh center freq, bandwidth, stages 2 poles per stage
  ]
  slave.pcm'plughw:0,0'}

$ cat .asoundrc | xclip
pcm.multi {
   type multi
   slaves.a.pcm "dmix:0,0" # ALC889 Analog
   slaves.a.channels 2
   slaves.b.pcm "dmix:1,7" # HDA NVidia
   slaves.b.channels 2
   bindings.0.slave a
   bindings.0.channel 0
   bindings.1.slave a
   bindings.1.channel 1
   bindings.2.slave b
   bindings.2.channel 0
   bindings.3.slave b
   bindings.3.channel 1
}

pcm.allcard {
        type route
        slave.pcm "multi"
        slave.channels 4
        ttable.0.0 1
        ttable.1.1 1
        ttable.0.2 1
        ttable.1.3 1
}

pcm.!default {
    type plug
    slave.pcm "allcard"            	
}