Comment 0 for bug 1002978

This is a metabug for all machines that are having phase inverted internal microphones.

If your internal mic is either completely silent (no signal), or you can possibly pick a very small sound, with much background noise, even though you have set gain to maximum, there is something you could try.

Install the pavucontrol application, start it and go to the "Input Devices" tab. Unlock the channels (there is a keylock icon), then mute the right channel while keeping the left channel at the volume you want.
If the internal mic is now working correctly, you have an inverted internal mic, so that your right channel cancels out the left one.

If so, please file a separate bug against the alsa-driver for your issue, make sure hardware info gets attached to it (either alsa-info as per https://wiki.ubuntu.com/Audio/AlsaInfo or the standard ones that follows when you do "ubuntu-bug alsa-driver" ), then write a comment in this bug, with your machine name and a pointer to the other bug.

As time permits, I'll try to work on fixing them for the next Ubuntu release. Thanks!
 -- David Henningsson