Microphone not working correctly on Lenovo B50

Question

I have just installed Ubuntu 15.10 on a brand new Lenovo B50. Everything works fine except for the built-in microphone.

I found a partial solution here: http://ubuntuforums.org/showthread.php?t=1885240. When I set one channel to 0 and the other to 100% as suggested in that post, the mic test here: https://www.onlinemictest.com/ shows that the mic is working correctly.

However, as soon as I start a Skype or Hangouts call, the level of the 'active' channel seems to be dynamically adjusted downwards. I can see this happening if I keep Pulse Audio open.

So, if I make a Skype test call for instance, I hear the first word at the correct level and then the voice goes very quiet.

Any suggestions please?

Answer 1

After some investigations I found the following:

Even if you do not allow Skype to adjust the sound level automatically, Skype adjusts the level of microphone down to zero, no matter if it is internal or external microphone.

Take a sound mixer, such as as veromix. Split the sound coming from microphone into right and left channel by unlocking the sound level adjustment. Then adjust right channel to zero and left channel to maximum. After that you can lock the level adjustment again, the position of level adjustment is then about 50%.

After that microphone in Skype will work normally.

Do not modify sound level for input e.g. in pulseaudio, it will give you the old situation without microphone sound. This adjustment will remain also after Restart.

Answer 2

Based on the previous answer I installed veromix and at the microphone I unlocked the channels, set the left to 50% and the right to 0%.

Here came the problem, that every time I adjusted the volume by volume keys, my microphone settings were set back to their initial state, nothing worked.

The solution was to uninstall libcanberra-gtk0, libcanberra-gtk-module, and wingpanel-indicator-sound (this last is only for elementary os). I still have libcanberra-gtk3-0, libcanberra-gtk3-module, so I can adjust sound with the volume keys, and it does not influence the mic settings.