where could it be coming from?

My power cable runs along my fireball then enters the driverside firewall near the pedals. it is then ran behind the driver seat, then crosses behind the glove compartment, around the spare, and finally to my amp in the trunk

my RCA cable goes from behind the HU to the passenger side where it runs below the door sills, back into the cabin behind the seats and then to the amp in the trunk

never do they cross and im still getting the alternator whine...any ideas why?

 

It's probably a problem with your amp's ground connection.

 

its actually okay for RCA cables to cross power cables at 90 degree angles, just not parallel. anyways you could be getting electrical interference from other oem electrical components(such as the fuel pump) that may have power wires running along the passenger door sill. do you also have any extra RCA slack coiled any where near other electrical components. to test this out try running the RCA cables directly from the headunit to the amp with out tucking it under the carpet and panels.

 

hrmm

could you give me some more information about this?

edit:
interesting, did some google searching about alternator whines and bad grounds
sounds like a grounding loop is what im experiencing