I am experiencing the problem described here: https://productforums.google.com/forum/#!topic/gmail/n1cpJq1mC8U.
Google Hangouts appears to be resetting the levels of my microphone.
That post has a solution:
To turn off the auto adjust:
cd ~/.config/google-googletalkplugin # get to google chat's directory
cp -p options options.bak # make a backup before changing stuff !
gedit options # edit the config file
now change one of the lines so that it reads as follows:
audio-flags=1
So far, so good. The problem is that I don't have a folder ~/.config/google-googletalkplugin.
My Hangouts works perfectly apart from the mic, so I guess I don't need to install anything, but how do I configure it?