So here is my setup. 96 TA Vert. Has a Monsoon head unit from a 2000 model. My car had no monsoon amp in the rear wheelwell. Several months ago I replaced the factory door and rear seat speakker with Polk Audio db651 coaxial speakers. A few weeks ago I added a GM9-AUX to the cd changer port so I could run my mp3 player through it. Everything works fine.

This weekend I added two things.

I added a MTX RE-Q. For those who don't know, it is a sound processor that helps add back in the bass that the factory head unit turns down as you increase your volume. It has speaker-level inputs and rca outputs. I mounted it in the right front kick panel in a little plastic pocket. I have read that this pocket is supposed to hold the factory keyless entry module, but the pocket is empty on mine, and the re-q fit perfectly. I tapped into the speaker output wires coming from the back of the head unit. I also tapped into the constant power wire of the head unit as well, and grounded the re-q on the post next to the kick panel that some other factory things are grounded on. The re-q has a switched power lead but it is not hooked up. It does not have to use that if it can sense your speaker output to switch it on. I have a twisted pair rca cable running from the re-q across the footwell to the passenger side of the transmission hump, then backward into the rear trunk.

That rca cable connects to the second thing I added. An Apline MRP-300 amp. Since the re-q only has one set of full-range outputs, the rca cable has splitters on the end to provide input to all four channels of the amp. So I don't have front-rear fade. The amp is mounted onto the rear wall of the trunk directly under the trunk latch. It is grounded at the same place that the rear lights are grounded, on a screw to the frame around the trunk latch. I have a power wire (can't remember if it is 4 or 8 gauge) running from the battery through the firewall down the passenger side under the carpet into the passenger rear wheelwell and over to the amp. Ground wire is less than a foot and the same size as the power wire.

I ran all new 16 guage speaker wires to all four speakers.

So I hook everything up and I have some pretty bad whine when the car is running, and I hear a little buzzing when the car is off. It is louder on the driver side than the passenger side. It does not seem to change with the speed of the car, but turning on the ac fan does change the tone a little. I have tuned the gain on the amp and the re-q.

Here is what I have done to troubleshoot the problem. I have disconnected the gm9-aux at the rear of the head unit with no change. I unplugged the antenna from the rear of the head unit with no change. I disconnect the rca inputs from the amp and the noise stops. I plug those back in and disconnect the rca outputs from the re-q and the noise stops. So the noise must be coming from the re-q somehow. Since the noise is louder on the driver side, I swap the rca connecters around on the re-q and the noise is now louder on the passenger side. So I think that rules out cabling or speaker wires.

I tried improving the ground on the re-q ( sanding paint off the bolt that it grounds to) and no change. In a last effort, I bought a rca noise suppressor (Scosche brand from Wal Mart) and still no change at all.

Sorry for the long post, but I wanted to describe with as much detail as possible. I know this type of thing is hard to diagnose without seeing it. Below are links to the equipment I bought, if that helps.

Any suggestions are appreciated.

http://www.crutchfield.com/p_500MRPF...00.html?tp=115
http://www.crutchfield.com/p_107DB65...651.html?tp=95
http://www.crutchfield.com/p_236REQ/...-Q.html?tp=428