From Open Sound System
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This page provide general troubleshooting tips. If these cannot help in solving a problem with OSS, you may wish to consult the 4front support forum.


  • Always read your driver's manpage. You can get the name of driver from 'ossinfo'.
  • Always test with osstest.
  • When consulting the forum, attach the output of 'ossinfo -v3' and 'ossmix'.

How do I...

  • Change mixer settings - ossmix (command line), ossxmix (GUI)
  • Start and shut down OSS - soundon, soundoff (both require root)
  • Save and restore mixer settings - savemixer (saving requires write permissions for, or using '-f' switch to select another filename)
  • Build OSS from source
  • Record and play sound - ossrecord, ossplay (though you should probably use more dedicated software like Audacity)
  • Other Tips And Tricks

I can't hear any sound!

  • Did OSS load at all? Run the command to examine loaded modules specific to your OS (lsmod, kldstat, etc.) to find out.
  • Does osstest work?
  • Are the outputs muted in the mixer?
  • Do the device nodes (/dev/dsp, /dev/oss directory, etc.) exist? If not, restarting OSS would probably create them. However, the following two commands should create them without need to restart:
    sudo ossdevlinks -r -v
    sudo ossdetect -d -v
  • Is the default output (the one linked to /dev/dsp) the one connected / outputting sound in osstest? If not, see here how to change that.
  • HDAudio: Are the jacks detected by OSS as output, actually the jacks connected to the speaker?
  • Ich: Some computers have an inverted external amplifier settings, so setting ac97_amplifier to 0 in $OSSLIBDIR/conf/osscore.conf would help. Gateway notebooks (Gateway 4542GP, 4028GZ, 7326GZ) in particular often have this bug.
    • $OSSLIBDIR is typically /usr/lib/oss, and can be determined exactly by the contents of /etc/oss.conf.
  • Is this an hardware issue?
    • Are the speakers muted?
    • Is the soundcard connected correctly to the speakers?
    • Do other drivers available for your OS (e.g. ALSA for Linux, FreeBSD native) work?

I hear noises!

  • Many soundcards' hardware requires output mixers be set to less than maximum (even down to 60% with a few cards).
  • Set vmix0-src to an higher setting using a mixer program.
  • Is the cable from the soundcard to the speakers connected correctly? Could it be too long?
  • Build and use OSS using the source from the public hg repository, perhaps a newer version will work better.

I can't get multiple sound clients to play on the same device!

  • OSSv4.0 for the FreeBSD platform doesn't support multiple clients to same device node on /dev/dsp device node (OSSv4.0 does support this on other platforms like Linux). It instead splits the mixing to separate devices: /dev/dsp1, /dev/dsp2, etc. Either set programs to use separate devices, or use a sound server like aRts, esd, etc., or upgrade to v4.1 which supports multiple clients on FreeBSD 7.1 and up.
  • Is vmix loaded and attached to the device? (Check if 'ossinfo -v3' shows more than one engine for the output device).
    • In OSS 4.0, (Doesn't apply to build 1016:) If vmix is not attached, make sure vmix1_masterdev in $OSSLIBDIR/conf/vmix.conf is set to the output device's device index (this can be determined via 'ossinfo -a'). ($OSSLIBDIR is typically /usr/lib/oss).
    • In OSS 4.1, 'vmixctl' command is used instead of vmix.conf (requires root permissions).
  • Are the vmix controls in ossxmix unmuted?

I can't get multichannel/5.1 output to play!

  • Some configurations require more than one cable connected to the speaker set. Make sure that as many cables as required are connected.
  • Some devices have the multich output at a different device node than the regular one, use /dev/dsp_multich rather than /dev/dsp as /dev/dsp_multich is always linked to the correct device. In the case of Dolby digital/AC3, /dev/dsp_ac3 is the best device instead of /dev/dsp_multich. It is possible that the node /dev/dsp_multich is symlinked to doesn't have vmix attached, so multiple clients won't play. See the tip above for how to fix this.
  • Some devices require changing settings in the mixer (e.g. by 'ossmix' or 'ossxmix') to work.
  • In OSS 4.0, (Doesn't apply to build 1016:) Set vmix1_multich=1 in $OSSLIBDIR/conf/vmix.conf ($OSSLIBDIR is typically /usr/lib/oss).
    • In 4.1, set vmix0-channels to "Multich" in the mixer.*sblive/audigy devices may require use of the sblive_digital_din (or audigy_digital_din) option in the device configuration file - see driver manpage.

I can't get sound/volume control from an application!