Ubuntu
pulseaudio package

  1. Bug #445849
  2. Comment #143

Comment 143 for bug 445849

Revision history for this message
Pebas (pebasmisc) wrote : Re: Highpitched Rattling like Sound with 5.1 Surround Configuration on Karmic Koala

I finally get rid of this annoying sound problem!

After testing a LOT of different configurations, this is what it worked for me:
1) Set profile to Analog Surround 5.1 Output + Analog Stereo Input
2) Replace volume = merge with volume = ignore in *ALL* elements (including masters sections) of files analog-output-speaker.conf, analog-output.conf, analog-output-desktop-speaker.conf and EVEN in PCM section of analog-output.conf.common (all of them located in /usr/share/pulseaudio/alsa-mixer/paths/).
3) enable-lfe-remixing = yes in /etc/pulse/daemon.conf
4) Restart PulseAudio
5) Use alsamixer (or Gnome ALSA Mixer) to set desired volumes for Master, PCM, Front, Surround, Center and LFE.
5) That's it!

Btw, I'm using a Creative SBLive!(EMU10K1) with pulseaudio 0.9.21-63-gd3efa-dirty
Ubuntu Lucid Lynx 10.04 amd64, kernel 2.6.32-21-generic (recently upgraded from karmic 9.10).

I think this workaround *virtually* bypasses all PA controls (like balance, fade, subwoofer and also front, rear and center faders) but this is hardly a problem for me since the annoying rattling highpitched sound seems to be REALLY GONE FOR GOOD, and I can alternatively use alsamixer to set individual volumes for each channel if I wanted to, and PA volume control works like a big "MASTER" fader.

That been said, I noticed that Master and PCM controls are kind-of mixed up in alsamixer. Both faders seems to control the same source, but in some "strange" way (I think this has something to do with what Daniel said about the for-now-missing separate mixer path file).

First of all, Master is not *really* master, but more like a Front-Left+Front-Right stereo mix and, of course, the same happens with PCM. Then, if ONLY one of those faders are down, the ENTIRE FL+FR mix gets muted, but if both faders are up (to 100%, for example), the FL+FR mix gets amplified beyond the overall 5.1 mix (and not just (logically?) doubled, but more like it only gets a 30 to 50% boost).

In fact, keeping that in mind, I discovered that setting Front, Surround, Center and LFE to 100% in alsamixer and both Master and PCM close to 80%, gets me a pretty good balance between voice (center) and music/soundeffects in 5.1 movies (and also better overall sound for stereo music/sound files).

Well, thats all for now. I'm very happy with my "new" working 5.1 setup :)

Thanks to all *positive* comments from above that helps me A LOT. Hope this can help others and, of course, let me know if there's something else I can do...