Sound buzzing (crackling) for sound Intel Corporation 82801G (ICH7 Family)

[Vladislav Muravyev]

Distorted sound for Intel Corporation 82801G (ICH7 Family) sound card.
See also:
https://bugs.launchpad.net/bugs/291798
$ lspci|grep Audio
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 02)
 You can see alsa-output from another bug:
https://bugs.launchpad.net/bugs/296011

Here is the link to the alsa-info.sh generated output (from thouse bug):
http://www.alsa-project.org/db/?f=92d2b0197f25c747eb59842a0f2678a92dd6d160
There are the same kernel, same sound card (snd_hda_intel module), all the same (without any updates).

1) So after computer start up, i had sound crackling. Then i make 'alsa-info.sh' generated output. After that, i've edited /etc/modprobe.d/blacklist , commented last line:
  # low-quality, just noise when being used for sound playback, causes
  # hangs at desktop session start (Ubuntu: #246969)
  # blacklist snd_pcsp
2) Then i reboot system, and the sound was without any crackling.
3) Another reboot return back into the same situation. So i've uncommented (see 1) it again (blacklist module snd_pcsp).
4) After reboot, there is the same crackling as in 1,3 cases.

All 'alsa-info.sh' output are similar except the order of the loaded modules. May be this is the cause? File 'all' contain olny order of the sound modules for all cases.

[Vladislav Muravyev (rex-lux)]

sometimes, after update-initramfs, there is no crackling at all for two or three boot up processes. And, sometimes, it (sound crackling problem) disappeared after i hibernate computer and then get it woked up.

[Vladislav Muravyev (rex-lux)]

The possible solution is to replace the following 3 lines in /etc/pulse/daemon.conf:
; default-sample-format = s16le
; default-sample-rate = 44100
; default-sample-channels = 2

With:
default-sample-format = s16le
default-sample-rate = 48000
default-sample-channels = 2

Either, it works for me yet. And after several reboots too.

[Vladislav Muravyev (rex-lux)]

After using gtk-recordMyDesktop playing with rhytmbox music began to crackle. So with this tutorial:
http://developer.novell.com/wiki/index.php/Feisty/HOWTO:_PulseAudio

I've changed my /etc/pulse/daemon.conf (see attachement) uncommenting some lines like this :
daemonize = 1
high-priority = 1
log-target = stderr
resample-method = trivial
no-cpu-limit = 1
system-instance = 1
disable-shm = 1
; default-sample-rate = 48000

And now it stops crackling after record with gtk-recordMyDesktop. May be it could help someone...

[Andy Whitcroft (apw)]

Other cases of crackling have been tracked down to the Alsa Mixer channel PCM being at 0, moving this to a sensible value sorted the issue. The PCM channel changing from 0 and back occured on my system randomly at kernel updates. Perhaps you could check that and report back here.

[Vladislav Muravyev (rex-lux)]

When i change PCM level to zero (neither Master, Headphone) it affects sound level, so it cannot affect sound crackling phenomena.

Front channel affects only internal speakers, so it cannot affect crackling.

Surround, Center, LFE channel doesn’t seem to affect volume level neither internal nor external speakers. May be there should be a solution.

But it seems that the problem affect linux kernel or wake up processes because after hibernate sound starts to crackle.

[Vladislav Muravyev (rex-lux)]

it doesn’t seem to affect me with all updates now even after sleep/hibernate phase.
vm@vm-desktop:~$ uname -a
Linux vm-desktop 2.6.27-9-generic #1 SMP Thu Nov 20 22:15:32 UTC 2008 x86_64 GNU/Linux
So, there are my current config file (/etc/pulse/daemon.conf).
The only difference with the previous one is ‘disable-remixing = yes’ option.