[pulseaudio-discuss] EMU10K1 + softvol + pulseaudio - distorted sound

Konrad Campowsky frollen at cs.tu-berlin.de
Sat Mar 20 03:13:42 PDT 2010

I am trying to get pulseaudio to work together with the dreaded
emu10k1 (Soundblaster Live Value to be exact) in a softvol scenario.
The latter is needed for me, since otherwise the amount of volume
change will be different for front/rear channels, even if I move the
pavucontrol sliders connected.
This is set up in my .asoundrc like this:

pcm.pulse {
	type pulse
ctl.pulse {
    type pulse

pcm.softvol {
    type           softvol
    	pcm         "plug:surround51"
    control {
       name        "Master"
       card        0

I redirect pulseaudio to the softvol device by having the following
line in /etc/pulse/default.pa:

load-module module-alsa-sink device=softvol

However, when playing sound through pulse audio, as in:
# speaker-test -t wav -c6 -D pulse
I get seriously distorted sound, even the channels are in the wrong
place. I also noticed, that the daemon spits out an error message when
starting up:

E: alsa-sink.c: ALSA woke us up to write new data to the device, but
there was actually nothing to write!
E: alsa-sink.c: Most likely this is a bug in the ALSA driver
'snd_emu10k1'. Please report this issue to the ALSA developers.
E: alsa-sink.c: We were woken up with POLLOUT set -- however a
subsequent snd_pcm_avail() returned 0 or another value < min_avail.

In an ALSA only setup everything is fine, e.g. when saying 
#speaker-test  -t wav -D softvol -c6

Likewise, everything works fine when not redirecting pulseaudio
through the softvol device (Except for the volume controls, which is
why I started this whole mess in the first place).

Also, there are no errors when I use "hw:0" as the slave for the
softvol device, however, I only get stereo then.
I have googled around for this, however could not find anyone with
this problem. As a matter of fact, other owners of emu10k1 based cards
suggest solutions like the above for properly managing their volume
levels, so it seems to work for them.
I also dont think it is a hardware defect (apart from the fact that
the emu10k1 might be broken by design), since I have the exact same
behaviour with two different SB Live value cards.

Has anyone witnessed these problems as well or can even provide me
with a hint on how to proceed further? 
BTW, if anyone knows a proper way to control the volume levels on this
card without the softvol solution, just tell me that and Ill be happy.

best regards,

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