got alsa working, but ...
kerry at gotss.net
Sat Apr 20 02:35:49 EDT 2002
The channels are given the names that the chip designers give them.
Why? It was originally thought that if all channel names were
standardized it would be easier for the user, but then all the
different soundcards came out with different features like
video channel, cd, aux, line etc,
and when mixers mapped these to other names it confused people even more.
The names make sense if you have read the ac97 spec,
oh, you haven't? neither have most other people <smile>.
Here is the quick and dirty necessarily incomplete scoop.
ac97 based cards have an input mux and an output mux.
They can output mono or stereo hence the master mono and master controls.
Record signals are fed into the card, run through input gain and to the adc, then
the output mux. This means ajusting line and mic only
change output signals not input signals input gain modifies
record volume. You can toggle a +20db gain for
the Microphone if you are using a condenser microphone.
Master volume changes the intire gain on the output mux.
PCM LINE MIC CD AUX VIDEO PHONE change volumes on various signals
before they hit the output mux.
Mute anything you don't need, and only capture from recording sources
you want to sample from. Capturing a source means
it will be fed into the input mux. the sblive can capture
multiple sources cd and microphone for example.
The sblive cards extend ac97 by allowing you to control the mixing path
which is why the alsa mixer is a bit tricky.
Yes there are a lot of channels, yes there are a lot of switches to fiddle,
but if it is all a bit much; you can boot windows to let
it make decisions for you on what you want your card to do.
The initial setup with alsa is a pain, but once you have your
/etc/asound.conf configured then you back it up and keep it about.
If you want alsa to start at boot then do the following under Debian:
update-rc.d alsasound defaults
this will take care of alsactl restore at boot and alsactl store at shutdown.
On Sat, Apr 20, 2002 at 12:00:54AM -0500, Cheryl Homiak wrote:
> Ok, I got alsa working.
> There were two things wrong.
> first of all, in one place i had a snd where there should have been a sound in
> my /etc/modutils/alsa.
> Second 9and this may help the person trying to get it to work with trplayer,
> etc.) I had left one setting muted that needed to be unmuted, just by missing
> it. you have to go through and check every
> single channel for whether or not it is muted. In aumix, pressing 'm" toggles
> everything; in alsamixer, it toggles only the channel/device you are on.
> I've still got some fuzziness, so one of the zillion settings or more isn't
> quite right yet. Wish they'd call all of the settings by plain english names
> and/or explain what all of them mean.
> Now I'm trying to figure out how to get my settings to be there when I reboot. I
> have to type "alsactl restore" to get them back every time I boot.
> Still not convinced I like the sound better than with oss; too soon to tell
> until I fine tune. Hope it actually succeeds with the reflector, since that's
> why I'm doing it. will practice on the echo server before I come in and blast
> anybody out again.
> Of course, if I'm deaf after experimenting, you'll be able to hear me, but i
> won't be able to hear you!
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> Speakup at braille.uwo.ca
Kerry Hoath: kerry at gotss.net kerry at gotss.eu.org or kerry at gotss.spice.net.au
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