[linux-audio-user] ALSA + multichannel card

From: Petar Nedyalkov <bu@email-addr-hidden>
Date: Tue Nov 15 2005 - 13:00:26 EET

Hello list,

I've successfully installed ALSA drivers 1.0.10rc3 on my server, having two
Terratec PHASE 28 cards. Each Terratec PHASE 28 has 8 audio outs, which can
be combined into 4 stereo out channels. I want to configure ALSA in such a
manner that will allow me to play different sound in each of the four stereo
channels. I.e. I want to combine the 8 outs into pairs and use them
separately.

I think I've solved it, but:

1. I'm puzzled why the amixer output for each card doesn't show I have four
stereo out channels but have Front, Rear and Side as stereo, and Center and
LFE as mono. Does this concern the ice1724 module?

2. When I play sound through the newly configured PCM devices it's volume is
low even if I've configured it with amixer to 100%.

Can you please tell me if my configuration is correct - does it combine each
of the 8 out channels into 4 pcm devices?

Does each of these 4 pcm devices represent one of the Front, Rear, Side,
Center/LFE channels (I want to control the volume through amixer).

I want to use it with mplayer - for instance `mplayer -ao alsa:device=card11
song1.mp3` and `mplayer -ao alsa:device=card12 song2.mp3`, etc.

Here's my .asoundrc sample for one of the cards:

pcm.card1 {

    type dmix
    ipc_key 321456
    ipc_key_add_uid true

    slave {
        pcm "hw:1"
        rate 44100
        format S32_LE
        period_time 0
        period_size 1024
        buffer_size 8192
        channels 8
    }

    bindings {
        0 0
        1 1
        2 2
        3 3
        4 4
        5 5
        6 6
        7 7
    }

}

pcm.card11 {

    type plug

    slave {
        pcm "card1"
        channels 8
    }

    ttable.0.0 1
    ttable.1.1 1

}

pcm.card12 {

    type plug

    slave {
        pcm "card1"
        channels 8
    }

    ttable.0.2 1
    ttable.1.3 1

}

pcm.card13 {

    type plug

    slave {
        pcm "card1"
        channels 8
    }

    ttable.0.4 1
    ttable.1.5 1

}

pcm.card14 {

    type plug

    slave {
        pcm "card1"
        channels 8
    }

    ttable.0.6 1
    ttable.1.7 1

}

Thanks for the help.

-- 
Cyberly yours,
Petar Nedyalkov
Devoted Orbitel Fan :-)
PGP ID: 7AE45436
PGP Public Key: http://bu.orbitel.bg/pgp/bu.asc
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Received on Tue Nov 15 16:15:04 2005

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