Hello,

When I use my microphone with skype (which use pulseaudio) or Linphone (which use ALSA), the microphone quality is VERY bad, noisy.
With audacity it's a bit better but still not very good, there is some noise also.

I muted all input except the one I am using.
If I set the input volume to 10% (in pavucontrol), it's acceptable in audacity, but the sound is low and still a little noise.
But in skype or linphone it's still bad, the voice seems saturated and too much noise.

The hardware seems to work correctly, it works fine under windows.
It's an integrated Realtek ALC892

anyone ?

Can you check (using alsamixer) that the Capture lines for your sound card are configured appropriately?
In particular, try adjusting the various items that exist, particularly if their name is "Line In" or similar.

Setting the "rear mic boost" to 0 improved a little.
Now the voice is less saturated, but there is still too much noise.
Other sound levels in alsa mixer are set to 0 to be safe.

This could indicate that the kernel driver still needs work unfortunately, or that something else is introducing this noise.
If you make a recording using "arecord" does that include this noise?

I can't start arecord, I never see the GUI
If I launch it from command line, all I can see in the terminal is tons of :
��������������������

Please note that 'arecord' is a CLI application, and as such you need to specify the name of a file which the recording should be written to.

Code: Select all

arecord recording.wav

The resulting 'recording.wav' file should then be playable in any music or video player.

Hmmm this is weird, with arecord the mic sound is fine.
But when I test from skype or linphone (a VOIP phone), the microphone sound is horrible. And they both claim they use pulseaudio.
I also tried to configure linphone to use ALSA and the sound is still horrible.

Any idea ?

I would suggest taking a look at this thread, which seems to have a similar issue.
https://bbs.archlinux.org/viewtopic.php?pid=920549

It would appear that Pulseaudio is mismanaging the microphone unfortunately.

all workaround I tested, like in the thread you posted, or other thread found with "pulseaudio crackling noise", does not fix my issue

For the record, I tested :
- adding tsched=0 in /etc/pulse/default.pa
- changing the sample-rate from 44100 to 44800 in /etc/pulse/daemon.conf
- launching skype with the following env variable : PULSE_LATENCY_MSEC=30
- lowering the PCM volume in alsamixer

Nothing helped so far...

Unfortunately there are no other known solutions to this - you will need to bypass Pulseaudio to workaround this issue.

For the record, upgrading pulseaudio to version 4.0 (with pulse-testing ppa) does not fix the microphone issue, and add a crackling sound output on skype, now I need PULSE_LATENCY_MSEC=30 workaround.

This is discouraging because it means it's not fixed in latest pulseaudio development versions

Have you tried changing the "device profile" that Pulseaudio uses to manage your sound card, to see if a better recording option is offered?
It is rather unfortunate it does not work in even the latest development code.

Yes I already tried to change the device profile.

Looks like PA is buggy with my audio chipset.
I reported it thanks to this web page :
http://www.freedesktop.org/wiki/Softwar ... enDrivers/

The bug is gone on Kubuntu 13.10