Some things I've noticed after doing this:
-mplayer volume control no longer has any effect.
-my sound capture devices have stopped working (mic, mic jack, line in)
-preamp must be enabled at least 20% with below settings to produce any sound through pcm at all.
A common complaint with alsa is that PCM (wav) playback, even on maximum volume is too quiet.
I created /etc/asound.conf with the following paramaters:
I am running debian squeeze linux x64 edition..
pcm.!default {
type hw
card 0
}
ctl.!default {
type hw
card 0
}
pcm.!default {
type plug
slave.pcm "softvol"
}
pcm.softvol {
type softvol
slave {
pcm "dmix"
}
control {
name "Pre-Amp"
card 0
}
min_dB -30.0
max_dB 30.0
resolution 6
}
Save the file as root as /etc/asound.conf
Now open a test wav file in aplay:
aplay -D default file.wav
You may need to kill any PIDs using alsa, run (as root)
alsa reload
This will print all the PID's using alsa, e.g.
# alsa reload
/usr/sbin/alsa: Warning: Processes using sound devices: 2338(mixer_applet2) 3612(chrome).
Now when you open alsamixer or gnome-volume-control you should see a new volume control called Pre-amp:
