Hopefully there are some audio wizards on here, or at least one.. So here's the deal - I just finished installing a *brand new* Sony Xplod head unit/iPod controller last night, and now I have a nasty *thump* every time I turn the head unit on/off, change CD tracks, put a new CD in, change radio stations, ANYTHING. The sub/amp I've had in the car the whole time I've owned the car, but it used to be hooked up to the factory head unit with a cross-over. Never had any problems like this.. I already know the noise isn't coming from the amp itself, not from the RCA cables, it's somewhere around the head unit. I've heard the power leads for the head unit can pick up noise, but I would think that would be like alternator whine O.o HELP!! Thanks in advance

Assuming you find that everything is hooked up correctly, the RCAs are probably just picking up noise (unless something is shorted or crossed inside the head unit). It *might* help to put a ground loop isolator in line w/ the RCA cables. I don't know if it would get rid of the popping, but it certainly helped get rid of a lot of noise that I had going through my externally powered computer speakers. You can go cheap and get a . Or you can spend the big bucks and get something made by Iso-Max. I had good results from the Radioshack one.

Again, these isolators are for ground loop noise, so I don't know if it will get rid of the pops in your system, but its probably worth a try.