I had an issue where my sound would just totally cut out for a few seconds, then come back, over and over. In BF3 and Diablo 3.
Discovered it started doing this after I updated my audio drivers to the latest version from Realtek's website. Their new drivers caused the problem. Re-install didn't fix. So, I rolled them back to the audio drivers from ASUS website (my mobo), instead of Realtek's website. Fixed my issue.
Believe I rolled back from 2.68 to 2.55.
May be worth a shot to try different audio drivers.
It's affectionetly called 'blast deafness' I believe I read. It's caused by when too much audio is playing at the same time this causes the game to stop all audio recover and keep going. Don't worry it's not your computer or headphones its the game it happens on all platforms.