The mixer utility is used to set and display soundcard mixer device levels. It may also be used to start and stop recording from the soundcard. The list of mixer devices that may be modified are:
vol, bass, treble, synth, pcm, speaker, mic, cd, mix,
pcm2, rec, igain, ogain, line1, line2, and line3.
Not all mixer devices are available.
Without any arguments, mixer displays the current settings for all supported devices, followed by information about the current recording input devices. If the dev argument is specified, mixer displays only the value for that dev.
To modify the mixer value dev, the optional left and right channel settings of lvol [:rvol] may be specified. The lvol and rvol arguments may be from 0 - 100. Omitting dev and including only the channel settings will change the main volume level.
If the left or right channel settings are prefixed with + or -, the value following will be used as a relative adjustment, modifying the current settings by the amount specified.
If the -s flag is used, the current mixer values will be displayed in a format suitable for use as the command-line arguments to a future invocation of mixer (as above).
The -S flag provides the above output without mixing field separators.
To change the recording device you use one of: