Sound was off-center, favouring the right ear, so basically whenever I walked it sounded like there was someone walking right next to me. Had to use the surround sound option on my G35 to fix it, but that gave me a horrible sense of direction.
Fix: Documents\BFBC2\settings.ini
SpeakerCount=2
--
http://www.gamefaqs.com/boards/957944-battlefield-bad-company-2/53772001