Testing Ground Points

Try upgrading your ground wire from your battery to your chasis ground.  The thicker the better.  Sounds like you have more than one ground loop...

O and the proper way to check for a good ground is to put the negative cable of your DMM on the negative of the battery cable and the positive to the spot where you want to ground.  Make sure you remove all paint and primer on the spot and test.  You should not read any voltage...If you get any voltage locate another spot until you get 0volts......

Right, well im going to tell you about how its set up right now, and the problems im facing. I know its not set up the proper way but im trying to eliminate the noises by different wiring...

I have 4awg wire for the positive going directly to the positive terminal, then 8awg to each amp from a power distributer. Exactly the same for the ground wires, i know its not the proper way but i tryed a proper earthing technique but it didnt help. These wires are run down the left hand side of the car. It powers a 300w amp for the 6x9s and a 600w amp for my sub. The noise is coming from both amps, and even from the hi-outputs of the head unit itself, but seemingly only from the rear channels, but not as loud as when amped. But when the 6x9s are direct to the head unit, all i hear is the alternator whine, but when amped, i hear everything electrical interfearing. My RCA's are run down the right hand side of the car. I've tried wiring the head unit directly to the battery too, but i still hear the noise. I've tried a noise supressor on the rca leads (plugs in line with the rcas) but it seemed to cut most of the sound, sorta like cutting all the mono sounds and only letting stereo through, but the noise was still there. I've also tried a supressor that is wired inline with the positive side of the head units power wires, but it did absolutely nothing.

Any sugestions? is this induced noise? should i try moving the rcas? I'll only try it if you believe this is the problem as its routed in the wells and is awquard and time consuming to move them....

Thanks in advance!

You mentioned before you might be using a shielded RCA cable.  If this is the case, make sure the shield is only connected to ground at the headunit end and the end at the amp is left disconnected.  Instead of removing the RCA's you can just unplug them and run another set through the car temporarily for testing.