Problems with software speech

[Michael Whapples]

On Sat, 2007-03-10 at 23:08 -0600, Farhan wrote:
> Hello, i'm not sure about your second question about the headphone issues, but most laptop soundcards now a days are cingle channel only, they don't do multichannel, sinse Windows xp has some weird kernel implementation to do that all for you, I think the only true multichannel soundcards you can get for laptops are the soundblaster external pcmcia cards.
> 
Let's be helpful here, now the reason may be known, but how to solve it.
Well as far as I know, alsa can do software mixing as well, you will
need to use a dmix device in the alsa configuration files. All the
possibilities with alsa configuration is quite wide, so it would be best
to read about it in the alsa documentation or search the internet for a
suitable solution. Also make sure that the software itself is really
using alsa, some programs still use OSS (trplayer, realplayer, flite,
freetts (so firevox plugin if you are using freetts), etc). If you need
to use something which uses OSS then it is still possible to use
software mixing, get it to use the alsa-OSS compatibility system by
putting the aoss command at the beginning of your command for the app
which uses OSS (eg. "aoss realplayer" will run realplayer with OSS
output going through alsa-OSS compatibility layer).

I don't actually know about your headphone issue, but it sounds like
alsa doesn't know about configuring (or it isn't configuring) a setting
for muting speakers when using headphones (it sounds like the switch is
software based rather than being a simple switch system. I think due to
the comment about the behaviour when using windows). Guesses at a
possible fix:
Check that alsa doesn't have a control for it somewhere.
See if the problem is solved in updated versions of alsa (if you are not
using the latest).
Last resort might be to find out if headphone and speaker volume can be
set separately (I know my laptop soundcard alsa gives a headphone
volume), and then you create two scripts (or one which either takes
options or knows how to toggle) that you run to mute speakers but not
headphones and to unmute speakers, and then you run this/these when
connecting and disconnecting headphones.

Hope some (if not all) of this is useful.

From
Michael Whapples