Ive had my CooperS since August, and have had the stereo installed nearly as long.

Alpine 9847 HU, upgraded front/rear speakers, 4 channel amp (2 channel running front, 2 channel > 1 for sub), 12" sub in the boot.

Origional setup had a sub box 36" x 13.5" x about 8-10" tall, with the amp mounted on top of the box. Power wires were run directly to the battery. RCAs from deck down the passenger side door sill to the amp.
This setup yeilded a very minimal amount of whine. Enough whine to drive you crazy when volume is at 0, but with any volume on the stereo, you couldnt distinguish the whine from the Alta intake..

Few weeks ago, i had to remove the sub box to boost my battery (left lights on all night). I put the amp back in, but never put the box in. Essentially, everything was exactly the same as my origional setup, however, the amp no longer had the sub box between itself and the battery. Whine. Whine. Whine. Enough to drive me crazy. It was always present unless stereo was CRANKED.

I did some research as to where i could put the amp to free up some cargo space. After some reading, i found there is a large cavity of space filled with styrofoam under the passenger and drivers seats. I removed the passenger seat, and sure enough, large cavity. I removed the foam and placed the amp in its hole. It fit. Perfectly. Exactly .5" on either side of the amp, and about 1.5 -3" free at either end which was perfect for running my power/ground/rcas and speaker wires.

This new location allowed me to better seperate the RCAs and speaker wires from power as the RCA/Speakers came from the front and plugged into the end of the amp near the door sill. The power and ground, which came from the back of the car were run along the centre of the car, and into the amp at the end nearest the centre console.

After wiring everything back up, reinstalling my seat, and hooking up the battery connections, I am happy to say I have lost -0- space for the amp or wiring, and have absolutely NO electrial whine.

I built a new sub box which i can put in and out of the boot within 10 seconds. All i need to do is pull the speaker wire out of the quick connects, tuck it under the rear carpet, and pull out the box. 100% stock space available on demand. Or leave it in for deep, clean bass.

Im happy.

Hopefully someone else gets ideas from this and is able to clean up there stereos.

http://www.bugs78.ca/photo/garagegal...iS/ampinstall/

 

Interesting ... I get slight whine but it varies with amplifier gain so I always assumed it was in the wiring, not the amp itself. Maybe I need to experiment some more.

What make is your amp?

 

How about some pics?

 

It is a cheap 4 channel Fusion Amp. Its actually not that bad of an amp, just a less known name. I got it from a store going out of buisness for a dance.

Please ignore the hack and slash job done on the carpet :-) Its all covered with new carpet, and looks 100% oem again. With the seat in, and the floor mats in place, no one would ever know :-) Until they turn up the stereo of course :-)

Heres the pics:
http://www.bugs78.ca/photo/garagegal...iS/ampinstall/

I couldnt be happier with the end result. Oh, and the sirrius adapter is under the other seat. but on the carpet. No where near as much space needed for th at little guy

 

Great clear pics of a nice installation - well done!

 

I have the exact same problem in my setup.

I have a Phoenix Gold 4x 50W rms amp, a 350W monoblock sub amp, polk spekaers and a Polk 12" sub.

I have the amps sitting ontop of the boot floor and I get nasty whine (also varying with the gain but always present).

I did an experiment and rotated my 4-ch amp 90 degrees so that it was perpendicular to the boot (with the sub amp disconnected) and the whine was dramatically reduced. I also tried put two shoe boxes between the boot floor and the amp and the whine was almost completely gone.

It's a matter of having the amps so close to the battery and the EMI causing the whine.

I have to make the effort to relocate my amps. Under the seats is a possiblity but I'd have to take out my seats (which I have done about 100 times now and it's driving me nuts).

 

I had the same whine issue as LordOfFlies when I had both amps in the boot. It's good to know that moving them to under the front seats helps alleviate the noise. Right now I'm un-amplified and without proper bass, since I'm waiting for it to warm up again before reinstalling everything. (The whine drove me nuts)