the power cable and rca's are seperated from each other but i still get a little bit of whinning noise, anyways i was at the sound shop and asked the guy to give me a noise filter but he told me that if i installed it my speakers would loose some power and they woulndnt sound as loud

 

Yeah, they're only worth it if you use them for their main purpose...to get rid of noise. They're installed in the main power line or RCA line (depending on the type of filter used) and do take away from the overall sound. Noise is usually caused by a bad ground. Try different grounding points on the components being used and the noise should go away, unless something else is going on.

 

Noise filters go on the RCA's, not the main power wire.

Correct that its usually a grounding issue though. Try grounding your radio where the amps are grounded, moving the amp(s) ground and making sure its bare metal, or the big three (upgrade your factory grounds under the hood).

 

Yeah, thanks for pointing that out. I had forgot about the RCA's. I edited my post. But, just for the record, there are also filters made for the main power line. It's mainly used to filter any accessory noises coming thru the main power line.