I've noticed some Alternator Whine coming from my subwoofer (via amp thats directly attached to the battery). I didn't have this before I had the MG, do I need to put some kind of isolator in? The whine doesn't always happen, in fact I think if I turn the radio off before I turn the car off, when I turn it back on after the car is started it isn't there. Its only when the radio comes on with the car that I get it. Its a whistling sound coming from the subwoofer thats directly associated to engine RPMs. How can I get rid of it!?