I was horsing around with the Google+ Hangout function last week. In installing the required Google / Flash plugins via Ubuntu Update Manager, I managed to cripple my system.
I wiped Flash off of my machine, did a fresh install…the whole works. To no avail. The bug (and fix) were strange enough to warrant a write-up.
First, the symptoms were strange. Any Flash video would run super fast…triple speed. While watching Cubs replays in fast forward was sort of amusing, I couldn’t get audio to work either. All media was wonky, including streaming audio. I tried to play an MP3 from my hard drive…playback was nonfunctional. That sort of led me to the solution:

I disabled the HDMI audio function, restarted Firefox, and that was that.
Why audio settings would spawn that sort of malfunction is beyond me. I am going to submit a bug report on this guy…too strange to let slip.