.asoundrc

cm.!default {
    type plug
    slave { pcm "jack" }
}

pcm.jack {
    type jack
    playback_ports {
        0 system:playback_1
        1 system:playback_2
    }
    capture_ports {
        0 system:capture_1
        1 system:capture_2
    }
}

ctl.mixer0 {
    type hw
    card 0
}