From Linux Man Pages
amixer - command-line mixer for ALSA soundcard driver
amixer [-option] [cmd]
DESCRIPTION
amixer allows command-line control of the mixer for the ALSA soundcard driver. amixer supports multiple sound-
cards.
amixer with no arguments will display the current mixer settings for the default soundcard and device. This is a
good way to see a list of the simple mixer controls you can use.
COMMANDS
help Shows syntax.
info Shows the information about a mixer device.
scontrols
Shows a complete list of simple mixer controls.
scontents
Shows a complete list of simple mixer controls with their contents.
set or sset <SCONTROL> <PARAMETER> ...
Sets the simple mixer control contents. The parameter can be the volume either as a percentage from 0% to
100% with % suffix, a dB gain with dB suffix (like -12.5dB), or an exact hardware value. The dB gain can
be used only for the mixer elements with available dB information. When plus(+) or minus(-) letter is
appended after volume value, the volume is incremented or decremented from the current value, respec-
tively.
The parameters cap, nocap, mute, unmute, toggle are used to change capture (recording) and muting for the
group specified.
The optional modifiers can be put as extra parameters to specify the stream direction or channels to
apply. The modifiers playback and capture specify the stream, and the modifiers front, rear, center,
woofer are used to specify channels to be changed.
A simple mixer control must be specified. Only one device can be controlled at a time.
get or sget <SCONTROL>
Shows the simple mixer control contents.
A simple mixer control must be specified. Only one device can be controlled at a time.
controls
Shows a complete list of card controls.
contents
Shows a complete list of card controls with their contents.
cset <CONTROL> <PARAMETER> ...
Sets the card control contents. The identifier has these components: iface, name, index, device, subde-
vice, numid. The next argument specifies the value of control.
cget <CONTROL>
Shows the card control contents. The identifier has same syntax as for the cset command.
OPTIONS
-c card
Select the card number to control. The device name created from this parameter has syntax 'hw:N' where N
is specified card number.
-D device
Select the device name to control. The default control name is 'default'.
-s | --stdin
Read from stdin and execute the command on each line sequentially. When this option is given, the command
in command-line arguments is ignored.
Only sset and cset are accepted. Other commands are ignored. The commands to unmatched ids are ignored
without errors too.
-h Help: show syntax.
-q Quiet mode. Do not show results of changes.
EXAMPLES
amixer -c 1 sset Line,0 80%,40% unmute cap
will set the second soundcard's left line input volume to 80% and right line input to 40%, unmute it, and
select it as a source for capture (recording).
amixer -c 1 -- sset Master playback -20dB
will set the master volume of the second card to -20dB. If the master has multiple channels, all channels
are set to the same value.
amixer -c 1 set PCM 2dB+
will increase the PCM volume of the second card with 2dB. When both playback and capture volumes exist,
this is applied to both volumes.
amixer -c 2 cset iface=MIXER,name='Line Playback Volume",index=1 40%
will set the third soundcard's second line playback volume(s) to 40%
amixer -c 2 cset numid=34 40%
will set the 34th soundcard element to 40%
BUGS
None known.
CATEGORY