Hi folks.

Thanks for all the comments, especially #127 (Daniel) and #143 (Pebas).

As Daniel mentioned in #127, the problem is based in the way newer PA
versions are merging the PA channel volume settings into the physical
channel volume settings. Furthermore, it seems to be unclear, whether
this is a PA bug, an ALSA driver bug, or a hardware bug.

In order to circumvent the merging problem, in #143 Pebas has left PA in
place but has pretty much completely withdrawn PA from doing any volume
control. Instead, he uses ALSA directly for this purpose. I tried and it
worked (many thanks for that), although I was left without any kind of
control from PA. How did you manage to retain a "big Master", as you
called it? Your method disables ANY volume control via the configuration
files.

I would still like to propose (yet) another workaround, which so far has
proven to work flawlessly for me, without any "at any reboot I have to
do this", or "I must not touch the XYZ slider, otherwise ..." things,
and with letting PA in control over the volume.

It uses the same basic idea as Pebas' approach: Avoid the merging
problem by keeping PA away from the hardware volume controls, and
instead do this via alsamixer or gnome-alsamixer. Nevertheless, PA can
still perform the volume control on a per-channel basis, but in
software, and then pass these modified values to the channels directly,
without this merging stuff. Instead, each PA channel maps directly to a
single hardware channel.

This can be achieved as follows (for the beginning user, I tried to give more 
detailled instructions at 
http://ubuntuforums.org/showpost.php?p=9363330&postcount=30): 
1. Start with unmodified files in /usr/share/pulseaudio, /etc/pulse, and 
~/.pulse.
2. Edit /etc/pulse/default.pa, outcomment the auto-detection modules 
(module-udev-detect, module-hal-detect, module-detect)
3. Instead, at this place in the file add a line "load-module module-alsa-sink 
device=surround40:0". Replace surround40 with whatever fits your config (i.e., 
5.1), and :0 with what fits your card (if you have only one, than 0 is correct 
already)
4. Go to alsamixer and adjust the hardware controls appropriately
5. Restart PA via "killall pulseaudio"
6. Adjust the volume in PA's panel applet (initially, it is set by PA to 100%!).

You should now have PROPERLY working volume controls in PA, and no
crackling, hissling, rattling. At least for me it worked that way. To
test it, open alsamixer and adjust the volume via the panel applet. In
alsamixer, nothing should change, but your speaker volume should.

Advantage: Working per-channel volume controls in PA (use pavucontrol to access 
the PA channels individually)
Big disadvantage: Static setup (haven't even included microphone yet, but this 
could be achieved).

I hope, this is helpful for at least some of you and does not only more
noise to the overall confusion.

If you test it, please give feedback.

Best wishes to all of you
-- Stefan

-- 
Highpitched Rattling like Sound with 5.1 Surround Configuration on Karmic Koala
https://bugs.launchpad.net/bugs/445849
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.

-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to