.TH ALSACTL 1 "25 Nov 1998" .SH NAME alsactl \- advanced controls for ALSA soundcard driver .SH SYNOPSIS \fBalsactl\fP [\fIoptions\fP] [\fIstore\fP|\fIrestore\fP] .SH DESCRIPTION \fBalsactl\fP is used to control advanced settings for the ALSA soundcard drivers. It supports multiple soundcards. .SH INVOKING \fBalsactl\fP [\fIoptions\fP] [\fIstore\fP|\fIrestore\fP] .SS Commands \fIstore\fP saves the current driver setup for the selected soundcard to the configuration file. \fIrestore\fP loads driver setup for the selected soundcard from the configuration file. If no soundcards are specified, setup for all cards will be saved or loaded. .SS Options .TP \fI-h, --help\fP Help: show available flags and commands. .TP \fI-f, --f\fP file Select the configuration file to use. The default is /etc/asound.conf .TP \fI-d, --debug\fP Use debug mode: a bit more verbose. .TP \fI-v, --version\fP Print alsactl version number. .SH FILES \fI/etc/asound.conf\fP (or whatever file you specify with the \fB-f\fP flag) is used to store current settings for your soundcards. The settings include all the usual soundcard mixer settings. More importantly, alsactl is capable of controlling other card-specific features that mixer apps usually don't know about. The configuration file is generated automatically by running \fBalsactl store\fP. Editing the configuration file by hand may be necessary for some soundcard features (e.g. enabling/disabling automatic mic gain, digital outputs, joystick/game ports, some MIDI routing options, etc.). .SS Configuration File Syntax There are some terms in the config file that bear explaining. The "capabilities" comments before each line will tell you which flags you can set for each channel. The comments start with semicolons. To set a flag, simply add it to the channel() line you want. .TP \fIhardware-mute\fP The soundcard itself is capable of muting the channel. Otherwise, kernel midlevel code will set the volume to minimum when an application requests muting on this channel. .TP \fIjoin-mute\fP Muting this channel can \fBonly\fP be toggled for left and right at the same time, \fBnot\fP independently -- even if you can control the volumes for left and right independently! .TP \fIstereo\fP The channel is stereo. .TP \fIrecord\fP Use the channel as a recording source. .TP \fIjoin-record\fP Recording from this channel can only be toggled for \fBboth\fP left and right at once; they cannot be toggled independently. .TP \fIrecord-by-mute\fP Allow recording the channel even if it's muted, so you can avoid feeding your record source to the speakers. Not all hardware supports this. .TP \fIexternal-input\fP This flag is purely informational: it tells you that the channel controls a signal from an external input (like Line-In or CD). This serves to distinguish external source channels from onboard source channels (like OPL-3 synth), which don't have this flag set. .TP \fIdigital\fP If you have a card with digital outputs and/or inputs, this flag toggles digital output/input for the channel. .PP Another feature of the configuration file is the \fIboolean\fP switches which are used to toggle certain card-specific advanced features. For example: ; Type is 'bool'. switch( "MIC Gain", false ) This shows that my card has a switchable mic gain, and that it's currently turned off. To turn it on, just change "false" to "true" and run \fBalsactl restore\fP. .SH EXAMPLES Let's say I have this entry in /etc/asound.conf for my PCM output. ; Capabilities: stereo hardware-mute digital. ; Accepted channel range is from 0 to 63. channel( "PCM", stereo( 40 mute, 50 mute ) ) When \fBalsactl restore\fP is run, volume will be set to 40 for the left and 50 for the right, but both will be muted (by hardware). .SH SEE ALSO \fB amixer(1), alsamixer(1), aplay(1) \fP .SH BUGS None known. .SH AUTHOR \fBalsactl\fP is by Jaroslav Kysela This document is by Paul Winkler .