Happens to me as well from time to time in DII - DKS. (English) I am on a Creative X-FI soundcard so, it wouldn't surprise me if that's more the problem than the game.
It's not a game breaker or anything, and like the other poster said it will sometimes correct itself, and others require a restart.
It happens most often for me after an auto-save/load or location change via teleportation of any variety.
Last edited by Ailurophile; 06/12/10 10:58 PM.