Here is the problem I am facing. I have a Premier P750MP. On my original configuration I had the front components connected to an amp as well as the sub. The rears were connected directly to the HU. I have recently added an amp for the rears and now when I power up the system the sub and the fronts make a loud popping sound. When the car is started a loud whine only comes out of the sub and the front components, but the rears do not whine at all. I have tried to relocate the grounds on the amps as well as the HU, and I have tried different RCA's and still no fix. When I disconnect the RCA's from the HU the sound goes away. The Power in the car is run down the driver’s side and the remote and RCA'S are run down the center of the car separated by about 6 inches. I have changed the wires around to different amps, and only the wires coming from the front and sub produce the noise. I am lost on this will someone please help?