engine whine through back speakers

[bassaholic]

Ok i have a pioneer 4600mp H/U and since i install my 4 channel amp im getting engine whine through rear speakers only. I replace the rca cable for the rear with some expensive shielded ones and still the same problem and i even ran it over the seat away from any power cables still the same problem. Is it a problem wid my H/U.... ?

[maldecido33]

check your grounds(HU and amp)

[squeak9798]

Yeah, try redoing your HU and amplifier grounds.

[bassaholic]

I check all the grounds plus the whine is only audible through the rear speakers not the components at all. but ill double check.