asoundrc

pcm.!default plug:pboth

pcm.pboth {
    type plug
    slave {
        pcm "both"
    }
}

pcm.both {
  type route
  slave.pcm {
      type multi
      slaves.a.pcm "dmix:CARD=PCH,DEV=0"
      slaves.b.pcm "headset"
      slaves.a.channels 2
      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
  }

  ttable.0.0 1
  ttable.1.1 1
  ttable.0.2 1
  ttable.1.3 1
}

pcm.headset {
    type plug
    slave.pcm "dmix:CARD=Device,DEV=0"
}