whine coming from speakers

I just got finished installing my new system in my 2004 BMW 325ci. I am running an Alpine 9885 head unit, JL XR series components in the doors, and no rear speakers (to port the bass from the sub in the trunk  to the cabin through the rear speaker openings). I am running a JL 250/1 for the sub and a 300/4 for the components in the doors (bi-amped).

I am experiencing alternator whine coming through the speakers when the system is running with the car running. There is no noise when the system is on but the car is not running. The whine increases in pitch with the engine rpm and decreases with engine rpm. It can be pretty audible while the music is at low volume, and barely noticeable at volume, or at speed.

I took pretty good care to avoid noise by running my signal RCA's down the driver side of the car, while the power cables in the car run down the passenger side. I have the ground attached to the factory ground point for the other grounds in the system in the trunk. The only thing I can really think of is that my rca's overlap the ground cable on their way to the amps which are mounted in the trunk. Could this be the issue?

Any other things I can check as a possible culprit to this?

The way you run your power and ground wires shouldn't give you a signal noise because of interference. The problem is most likely your RCA cables. Are you COMPLETELY sure that there isn't any power or ground source running near them? Beamers have like a billion miles of wiring in them and you might be getting a signal from something that you don't even know is there. It dosen't take much to get a whine. If you find a place that there might be a problem, but you can't run your wires anywhere else try insulating them. Hope this helps

This isn't really a noise in the speakers, it is alternator whine. It corresponds with the rpm of the engine. From everything I've read here, that indicates a ground loop condition or other faulty ground. I haven't had a chance to check it yet, but I plan on doing that tomorrow. I hope to god it is a ground issue and not a problem with the RCA's...it was pure hell running those rca's to the trunk. The car is built like a tank and taking it apart and running cables is not something I plan on doing again.

Thanks for the responses..hopefully I'll get this nailed. I've been installing this system for two weeks now, and it is just about finished except for details like this.

Unplug the rca cables from the amp and plug in a set of muting plugs. Muting plugs can be made by taking a old pair of rca cables, cutting the end off leaving about 3" of wire. Splice the inner and outer section of the wire together. This shorts the wires together. Plug them into the amplifiers. Do this to all input, if there is no more noise when the vehicle is running, chances are highly likely that you need to start looking at the deck. Read the what is a proper grounding sticky and the Q&A thread as well. There is ample things to read about that may point you in the right direction.

Thanks Rob.....your input is highly valued.

The issue has been resolved. I feel kind of stupid for leaving this part out of my initial post about my configuration, since it turned out that there wasn't really a problem afterall. I have two JL amps, a 300/4 for the components, and a 250/1 for the sub. Both amps were all wired up and ready to go, but I had not hooked up the speaker wire to the sub yet. The rca's were plugged in, but I hadn't actually connected the sub to the amp. I don't know why that would be a problem, but now that I have hooked up the sub, the whine is gone.

Although I'm happy that the system is quiet now, I would like to make sure that there isn't an issue that is being masked somehow. Why would everything be noise free once the sub was hooked up to the amp? Is it still possible that the sub amp has a bad ground or there is some other issue that is being masked because the sub isn't reproducing the frequencies? Both amps have 8 guage wire going to a single distribution block, which then in turn has 4 guage going to the factory ground bolt in the trunk.

Anyway, thanks to everyone, and the ground sticky was very informative and helpful while I troubleshot this problem. This forum is an invaluable resource to those of us who take on car audio installation with limited knowledge and experience.