Can't get sound from USB audio device

[NoOp]

On 04/16/2007 04:33 AM, Dave M G wrote:
> Ubuntu Users,
> 
> Recently my friend gave me an old computer of his, and I'm going to turn 
> it into a dedicated MythTV media device.
> 
> But that's going to be tough without sound.
> 
> The only sound device connected to the machine is an external USB sound 
> device (Kenwood). I've tested this device on my other computers and I've 
> verified that it works.
> 
> When I open the Volume Control GUI and click File and then "Change 
> Device", I can see that my "Kenwood USB Audio" device is the only device 
> listed there.
> 
> When I open up Preferences-Sound, I can use either "Autodetect", or "USB 
> Audio", and press the "Test" button. I get no errors, and it shows an 
> indicator that something is playing, but no sound.
> 
> Even when I open a video file or MP3, I get no errors, whereas I would 
> expect a "cannot connect to sound device" error, like I've seen before 
> in similar circumstances.
> 
> And then, oddly enough, when I opened Gedit, I got a stream of errors 
> that looked like this:
> 
> ALSA lib confmisc.c:670:(snd_func_card_driver) cannot find card '0'
> ALSA lib conf.c:3500:(_snd_config_evaluate) function 
> snd_func_card_driver returned error: No such device
> ALSA lib confmisc.c:391:(snd_func_concat) error evaluating strings
> ALSA lib conf.c:3500:(_snd_config_evaluate) function snd_func_concat 
> returned error: No such device
> ALSA lib confmisc.c:1070:(snd_func_refer) error evaluating name
> ALSA lib conf.c:3500:(_snd_config_evaluate) function snd_func_refer 
> returned error: No such device
> ALSA lib conf.c:3968:(snd_config_expand) Evaluate error: No such device
> ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM default
> ALSA lib confmisc.c:670:(snd_func_card_driver) cannot find card '0'
> ALSA lib conf.c:3500:(_snd_config_evaluate) function 
> snd_func_card_driver returned error: No such device
> 
> So I hit the Google trail, and didn't see anything that I could 
> understand which had concrete advice on what to do about it.
> 
> But I came across this web page:
> http://ubuntuforums.org/showthread.php?t=402293
> 
> ... which seemed to have some relevant information on editing the 
> /etc/modprobe.d/alsa-base file.
> 
> By changing the first ltwo lines in that file to:
> install sound-slot-0 /sbin/modprobe snd-usb_audio
> #install sound-slot-1 /sbin/modprobe snd-card-1
> 
> Got rid of the errors above, but I still didn't have sound.
> 
> At this point I realized I was whacking away at a file that I didn't 
> really understand, and thought I should turn to some experts to see if I 
> was barking up the right tree.
> 
> Is this the right file to be editing to fix my audio woes? Is there 
> anything else I should be checking to diagnose this problem?
> 
> Any advice or information much appreciated.
> 


Have a look at:

https://help.ubuntu.com/community/SoundTroubleshooting

and see if anything there helps.

Also, you might try:

sudo /etc/init.d/udev restart

and see if that makes any difference.

Just a WAG (Wild A#$ Guess), but you might try loading the usb sound
module at startup:

gksu gedit /etc/modules

add:

snd-usb_audio

as the last line. Save the file.
Restore the /etc/modprobe.d/alsa-base to what it was:

install sound-slot-0 /sbin/modprobe snd-card-0
install sound-slot-1 /sbin/modprobe snd-card-1

Reboot.