I installed a new sound card, a Turtle Beach card, and can't seem to get sound out of the optical out. lspci says it is a CM8738 chip. I can get static out the front two channels with the following command but that is it so far (when the test says center, nothing works):

speaker-test -Dplug:iec958 -c 6

When sound does come out those two channels, my reciever says PCM, but when the test says other channels, it says NO AUDIO INPUT. I disable the onboard intel audio from the bios.

aplay -l says:

**** List of PLAYBACK Hardware Devices ****
card 0: CMI8768 [C-Media CMI8768], device 0: CMI8738-MC8 [C-Media PCI DAC/ADC]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: CMI8768 [C-Media CMI8768], device 1: CMI8738-MC8 [C-Media PCI 2nd DAC]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: CMI8768 [C-Media CMI8768], device 2: CMI8738-MC8 [C-Media PCI IEC958]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Currently I have the following switches checked: IEC958 5V IEC958 Output

I also tried: asoundconf set-default-card CMI8738

I don't really know very much about sound trouble shooting, so any help is appreciated. I am using Ubuntu 9.04

If I uninstall pulse, it works okay for XMBC, but nothing else has sound. Not sure what I need to do with the Ubuntu Config.

Also, my card is: Turtle Beach TBS-3300-01 Montego DDL Sound Card

  • No sound out of the optical out? Dang. I can't get any light out of my speakers, either... ;) Oct 9, 2009 at 11:59
  • @GorillaSandwich: you can see 'em can't you? :) Oct 10, 2009 at 15:10

2 Answers 2


Basic troubleshooting steps (taken from the DigitalOut with ALSA page I posted to your earlier question):

  1. Check that the card is found and available (already done! good job!)

  2. Check mixer settings (try TonyUser's suggestion of gnome-volume-control-pulse first, then try running alsamixer and seeing if you need to adjust things there as well).

  3. Try playing back a WAV file: "aplay -D hw:0,2 myfile.wav" or possibly "aplay -D plughw:0,2 myfile.wav". If it works your receiver should indicate it's getting PCM data.

  4. If that doesn't work, look for entries listed as "digital audio playback" in the output of "cat /proc/asound/devices". Note the numbers in brackets ("[0- 2]" should be one of them; that's the one we tried in Step 3 with the "hw:0,2" parameter). If there are other entries, repeat Step 3 with each parameter.

  5. If it still doesn't work, return to Step 2 and play with mixer settings.

  6. Once you get it working, you can grab a DTS WAV file from this link to test that digital pass-through is working on your card -- be sure to substitute in the right hw: numbers that you got to work earlier: "aplay -D hw:0,2 Norrlanda.wav". If it works, your receiver should indicate it's getting DTS data.

  • Thanks, going to go through this over the weekend. I got digital pass through and PCM working with xbmc when I uninstalled pulse, so now I just need to get regular sound ( ie wav like you mentioned, or the test sound in Ubuntu's sound settings ) to work... Oct 9, 2009 at 11:41
  • So actually, do I want to try to get this all working with Pulse, or can I live without Pulseaudio? Is it like esd, where if I go with just Alsa, I will only one app can have sound at a time? Oct 9, 2009 at 11:49
  • the steps are important -- follow them and use the "aplay" command and you're guaranteed to find the right output device. you can puzzle out the sound settings GUI later. Oct 9, 2009 at 12:01
  • that was probably ESD on OSS (old sound system), which only allowed one program accessing the soundcard at a time. that's partly why they switched to ALSA, to fix that. if you don't have Pulse installed now, go thru the "aplay" steps with ALSA, and make sure it works there -- ALSA's the lower level anyway; if it doesn't work there Pulse can't help. Oct 9, 2009 at 12:06
  • So in the end, a reboot after removing pulse got everything working. I thought killing pulse and restarting X would be the same as a reboot, but apparently something else is going on... Oct 13, 2009 at 12:55

I've recommended installing pavucontrol before to deal with PulseAudio input/output issues. But I just found a guide HERE about replacing the default volume control with gnome-volume-control-pulse which may help you out.

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