Hi - I have a weird problem (that is, my CAR has a weird problem) with the right upper dash speaker on my 2001 xk8 with the premium sound...

Here is the problem: Once I turn on the key, the right upper dash speaker emits a high pitched whine from that one speaker only... when I start the car, that persistent whine remains, but I get another whine or squeal in addition that gets louder if I rev the car (again, only in that one speaker). ALSO, the sound quality out of that speaker is marginal at best.

From a separate post in the "XJ ( X308 ) XJ8 / XJR" section (I was responding to another post of a similar issue), some have said I probably have a GROUND issue. Now, what would be the best way to track down this ground issue... I assume that both wires on the speaker go back to the amp in the trunk - or are they using the body as ground (I can't imagine)?? Where might this ground issue be and what would be the best approach to sort it out? It's weird since it is just that one speaker only... any and all input is greatly appreciated

And I did swap the dash speakers and the noise is still only on that right upper side...

Thanks!
Chris