[LAU] Combining two stereo devices on one card into one four-channel device (M-Audio FastTrack Pro)

[David Balch]

Hi,

I have an M-Audio FastTrack pro
(http://www.m-audio.com/products/en_us/FastTrackPro.html), which
presents its four playback channels as two devices  (hw:1,0 + hw:1,1).

I want to combine the two devices into one, so I can use all channels
in Jack - but I'm struggling to get it working or even be sure that I
understand .asoundrc

Amongst other things, I have tried using the config from
http://www.mail-archive.com/alsa-user@lists.sourceforge.net/msg23839.html,
but it doesn't work:

$ aplay -vv -Dftpro:1,0 test.wav
ALSA lib conf.c:4612:(snd_config_expand) Load defaults error: File exists
ALSA lib pcm.c:2211:(snd_pcm_open_noupdate) Unknown PCM ftpro:1,0
aplay: main:608: audio open error: File exists

Full alsa-info.sh output:
http://www.alsa-project.org/db/?f=0fc7694be834a5bcaba51317a0660de22911a02f

Another .asoundrc I've tried:
----8<----
pcm.fasttrackmulti {
 type multi
 slaves.a.pcm "hw:1,0";
 slaves.a.channels 2
 slaves.b.pcm "hw:1,1";
 slaves.b.channels 2

# First 2 channels of first soundcard (playback)
 bindings.0.slave a
 bindings.0.channel 0
 bindings.1.slave a
 bindings.1.channel 1

# First 2 channels of second soundcard (playback)
 bindings.2.slave b
 bindings.2.channel 0
 bindings.3.slave b
 bindings.3.channel 1
}

ctl.fasttrackmulti {
 type hw
 card 2
}
----8<----

There is never any sign of the .asoundrc devices in aplay -l output.

Any ideas how I can get it working? Thanks in advance for any help!

Cheers,
Dave

--
http://www.witchesband.com/