Ok, I posted on here about a problem I had when I first got my car and was wiring in the stereo system. No one had ever heard of anyone having this problem then, so maybe now someone has run in to it.

Here's a quick run down of the equipment:
Pioneer DEH-8600 head unit
Polk Audio components up from, 6x9 3-ways in the back
TREO 15" Woofer powered by Concept CC-D800A amplifier

Now, here's the problem. I get noise in the speakers unless I power them directly from the head unit.

I have some Monster Cable RCA's running from the head unit's out to the back of the car, where I had the amplifier for Polk speakers. Power for the amp came directly from the battery. Ground cable was 1' long and grounded to the body.

Turn on the car, and BOOM huge amount of computer noise coming from the speakers.

I made sure my RCA cables and speaker wires didn't run near any other wires and that wasn't it. I even went so far as to take out all the speakers and head unit it, move them to the trunk and hook them up with some short wires, and the noise was still there. I tried 2 different head units (other was a JVC, can't remember the model). I tried several amplifiers, my concept, an Autotek, a JVC, and a Sony. All the amps showed the same problem too. I even tried different speakers (Infinity reference speakers).

Just for the hell of it I disconnected the car's connections to the battery and only put in the stereo, noise gone. So the noise is definitely coming from the car.

What could it be???

Currently I have the speakers powered by the head unit, and there's no noise... but not quiet as much power either

I'm able to, using the low pass filter on the concept amp, eliminate 99% of the noise from the subwoofer (There's still a low hum, but not that noticeable unless your back by the woofer)

I even tried taking the speaker out of the head unit, running in to a line level converter, then to the amp, with the same results. So the noise is coming from the connection to the battery.

Another thing I did, just because I was completely baffled, was hooked the stereo and amp to an EXTERNAL battery from the car... noise wasn't there. So, definitely electrical system, but what is causing it, and how can I eliminate it from the stereo??

Any suggestions?

I have a video around here somewhere with the noise in it. It's a computer noise.

-Dave

 

Let me see something,

Just for the hell of it I disconnected the car's connections to the battery and only put in the stereo, noise gone. So the noise is definitely coming from the car.[ Power for the amp came directly from the battery. Ground cable was 1' long and grounded to the body. Sounds like you might be getting interferace because of a ground that is not electrically connect good enough.

Try taking a wire and ground to the neg term of the battery instead of the body. I just recently rewired the whole power system. There is also a ground lug behind the battery this is originally where I hooked up my ground prior to the rewiring and had no problem. Here is a pic of the new install and the arrow point to the ground lug behind the battery below the lip. Hope this helps. Just thought of something else!! There is a lil plug that goes into the stock radio system, I think it has 3 wires going into it. It is the cars computer buss. If you used this for switched power that might be your cause also. I tapped off the lighter for my switched power.