There seem to be two microphones detected by my system. The one that is selected by default doesn't work. I found an app called indicator-sound-switcher which allows me to switch to the other mic which does work but I have to do that every time I log out or reboot.
When I go to the input tab of the sound settings, it seems that the default microphone (not working) is called "Internal Microphone" and the other (working) is called "Microphone".
If I use pavucontrol, it shows both microphones. If I deselect the "set as default" button on the Internal Microphone, it is automatically reselected by the next time I switch to that microphone.
I don't have any microphone plugged in. Just the built-in one on my laptop.
I'm not sure where to start looking for clues as to how to fix this. Any help would be appreciated.
I'm running 14.04.