I have a 2005 Tahoe with a buzz coming from the Bose speaker in the right rear passenger door when the radio is on. The pitch of the buzz increases with engine RPMs. The dealer said our speaker was bad but before approving a replacement ($250+) I switched the right speaker with the left speaker(which was not buzzing) and the buzz continues to come from the speaker in the right rear passenger door. I suspect now that there is nothing wrong with the speaker itself and that there might be something wrong with the signal feeding that right rear door which would suggest a problem with the radio/amp, etc. Anyone have experience with problems such as this one?