.SH DESCRIPTION
\fBalsactl\fP is used to control advanced settings for the ALSA
-soundcard drivers. It supports multiple soundcards.
+soundcard drivers. It supports multiple soundcards. If your card has
+features that you can't seem to control from a mixer application,
+you have come to the right place.
.SH INVOKING
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.).
+automatic mic gain, digital output, joystick/game ports, some future 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.
+"capabilities" comments before each line tells you some
+characteristics of each channel. This is purely informational; these
+are not flags you can set. Capabilities are listed below.
.TP
\fIhardware-mute\fP
.TP
\fIrecord\fP
-Use the channel as a recording source.
+The channel may be used as a recording source.
.TP
\fIjoin-record\fP
.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.
+This channel can be recorded even if it's muted, so you can avoid
+feeding your record source back to the speakers.
.TP
\fIexternal-input\fP
-This flag is purely informational: it tells you that the channel
+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.
+source channels (like OPL-3 synth).
.TP
\fIdigital\fP
-If you have a card with digital outputs and/or inputs, this flag
-toggles digital output/input for the channel.
+This channel is fed to an onboard digital mixer for possible hardware
+processing (for instance, surround-sound processing if your card has it).
.PP
-Another feature of the configuration file is the \fIboolean\fP switches
+The configuration file also has \fIboolean switches\fP
which are used to toggle certain card-specific advanced features. For
example:
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.
+currently turned off. To turn it on, just change "false" to "true,"
+save the config file, and run \fBalsactl restore\fP.
.SH EXAMPLES
; 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).
+ channel( "PCM", stereo( 40 mute, 50 mute ))
+When \fBalsactl restore\fP is run, the PCM volume will be set
+to 40 for the left and 50 for the right, but both will be
+muted. Since this card supports \fIhardware-mute\fP, muting will be done by
+hardware rather than by zeroing the levels.
.SH SEE ALSO
\fB
.SH AUTHOR
\fBalsactl\fP is by Jaroslav Kysela <perex@jcu.cz>
This document is by Paul Winkler <zarmzarm@erols.com>.
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