Re: sound card trouble.
I had a similar problem with the "Matrix" game awhile back. I threw that game away because I was upset about the dialogue too. Try reinstalling the game. SHould have had it replaced because maybe it could be a bad CD.
Does the sound come out nice other than in BF2? So the problem is only isolated in this particular game and nowhere else? Try reinstalling it.
*Fact: Microsoft Window's Blue Screen of Death vs Computerforums.org's White Screen of Death. Which is worse?