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hany tawfik
Asked: 2012-11-06 14:14:39 +0800 CST

MPD to play music to single channel of my multi-channel card?

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I installed an Ubuntu 12-04 LTS server for a special background music application of mine, where I am using the server with an Asus Xonar DS sound card.

The installation is successful, the MPD is working, the sound card is working with Alsa and its libraries installed except for alsa-oss. Alsamixer is working fine with left/right sides of each channel volume control through Q/Z letters shortcut when alsamixer is open in terminal .

Using the command speaker-test -Dplug:surround71 -c8 -l1 -twav, I can hear every voice message coming out from the card at the right connector, so "front right/ front left" voice message are coming from first output in the card back, while the other outputs are silent..so on.

The problem is that MPD is playing on all outputs simultaneously the same audio. I have been trying various configurations for the last 12 days with out any success, including trying to put mappings in the /etc/asound.conf

Can any body help me achieve the above, or direct me to the right configuration of MPD or asound.conf?

mpd

2 Answers

  1. I have an Asus Xonar DSX card. I use only alsa on my Ubuntu 13.04 based system and have split up the card to 4 distinct channels, so I can send the audio to any of them using any mpd client. My /etc/asound.conf is here:

    pcm_slave.eightchannels {
        pcm "hw:0,0"            # or "hw:1,0" for the second card
        #pcm "CARD=DSX,DEV=0"
        channels 8
}

pcm.stereo1 {
        type plug
        slave.pcm {
                type dshare
                ipc_key 87654321
                slave eightchannels
                bindings [ 2 3 ]
        }
}
pcm.stereo2 {
        type plug
        slave.pcm {
                type dshare
                ipc_key 87654321
                slave eightchannels
                bindings [ 4 5 ]
        }
}
pcm.stereo3 {
        type plug
        slave.pcm {
                type dshare
                ipc_key 87654321
                slave eightchannels
                bindings [ 6 7 ]
        }
}
pcm.stereo4 {
        type plug
        slave.pcm {
                type dshare
                ipc_key 87654321
                slave eightchannels
                bindings [ 0 1 ]
        }
}

    The outputs in /etc/mpd.conf are set up like this:

    audio_output {
        type            "alsa"
        name            "Schlofzëmmer"
        mixer_device    "hw:0"
        device          "stereo1"
        mixer_control   "Master"
        use_mmap        "yes"
}

audio_output {
        type            "alsa"
        name            "Kichen"
        mixer_device    "hw:0"
        device          "stereo2"
        mixer_control   "Master"
        use_mmap        "yes"
}

audio_output {
        type            "alsa"
        name            "Living"
        mixer_device    "hw:0"
        device          "stereo3"
        mixer_control   "Master"
        use_mmap        "yes"
}

audio_output {
        type            "alsa"
        name            "Iesszëmmer"
        mixer_device    "hw:0"
        device          "stereo4"
        mixer_control   "Master"
        use_mmap        "yes"
}

    This way I can choose on which output(s) (speaker pairs) the music plays.

    • 1

  2. you could try the JACK audio server, you would have to replace it with ALSA, but as i recall 3 years ago you could specify the exact output and input.

    i dont know how well it'd work with your own application, but you can certainly try it. (it'd be explained here, in german)

    i dont know if i gave you a hint or just wasted your time, let me know, spheniscida

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