I have brand new Cuspid USA Am-4310 1600W amp with 2 12" Xtreme sound Cuspid USA 600W subwoofers. When i have everything hooked up properly, there is a high pitched squeeling noise when the subwoofers are turned on. with my car engine running. I have had an amp before hooked up to my rear speakers, and never had a problem with that. please help. thanks
definally alternator noise caused by a bad ground or getting in through poor quality RCA's.
are your RCA's running down the opposite side, away from power wires??
try to change ground points, make sure all grounds are clean and secure and as short as possible. also look at the negitive post and the battery to chassis ground as i've found that can cause unwanted noise if they are not clean.
try to swap out the RCA's, run them outside the car or down the middle.