loud hissing.

[~=PoT=~Clyde]

I leave teamspaek running all the time. I sometimes get a loud Hissing, screeching, sound, Kinda like Music sometimes. Its very loud. Sometimes restart the game im in and sometimes have to restart teamspeak. Sometimes it starts this noise without a game.
the only games I play are UnrealTournament and ut2k4.
Thanks in advance.