Comment 21 for bug 433055

Steve,
that's it! Unlocking the two mic channels in pulseaudio's volume control input devices and setting one of the two mic channels to 0% works around this bug in pulseaudio! I can now see the mic level bar in the volume control follow closely the volume meter (recording) level bar, and arecord and skype are now receiving the expected signal from the internal mic. Re-locking the two mic channels together makes pulseaudio lose the mic signal again, so the problem is likely in how pulseaudio is handling these two mic channels together.

HW: http://www.alsa-project.org/db/?f=a6a27f825b91fd44463b7fec8ee4d66a6851ebe5
Acer Aspire 1 AOA150 v0.3309
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 02)
00:1b.0 0403: 8086:27d8 (rev 02)
 Subsystem: 1025:015b