i just installed a new 200.4 amp to my car... everything is perfect when the engine is off and the car is on... when im driving there is a very high pitched engine noise that gets higher as my rpms go up and lower as my rpms go down... what would be causing this to happen? or more specifically where? thanks a lot

 

The noise you are hearing is either caused by a ground loop or RFI (radio frequency interference). Did you use RCA cables that use "twistd pair" construction? This is critical in a car stereo installation. RCA cables that only claim to be shielded will not prevent RFI from entering the stereo system. Twisted pair RCA cables reject noise and are a must in a car stereo. Where do you have the amp grounded? Do you have a clean metal to metal contact with the car's chassis?

 

yeah i have the twisted rca wires... i really think i have a clean metal to metal contact

 

The first thing you need to do then is get a set of muting plugs. These are just RCA plugs that have the barrel shorted to the center pin. Remove your RCA cables and plug the muting plugs into the amp. This shorts the inputs and provides the amp with a 0 volt input. Start you car and then turn on the stereo. If you still hear the alternator whine you have a bad ground. If the noise is gone then the noise is entering the stereo further upstream.

 

ok thanks a lot LS1 RULZ... ill let u know how it goes

 

LS1 RULZ - i was playing around and i noticed my driver's side door speaker was barely playing while the other 3 speakers were playing at the right volume... so i go to my amp and the 2 RCAs for the 2 front speakers were plugged in all the way... so i switched the black on the left and red on the right to red on the left and to black on the right... when i did this the passenger's side door speaker was barely playing and the other 3 were playing at the right volume... so out of the 2 RCAs the black one wasent working while the red one was working... everything was brand new so im sure there was a problem in my install somewhere... what do u think i did?

 

It sounds like you may have a problem with your HU. Do you have anything else in the signal path? An EQ perhaps? If not then that pretty much only leaves the HU as being the problem.

 

no theres no eq or anything... u think i just have a loose wire or connection in the head unit or something

 

since u think something is going on with my head unit - when i take it off what should i look for or make sure i did when it comes to that engine noise problem im having?

 

im in the process of doing this... i cant seem to find out my problem... the speaker will randomly fade in and then randomly fade back out

 

I don't think it's anything you can repair yourself. You probably need to send it in for repair.

 

hey same problem i had!! ummm..here is what i did with mine. i went to best buy, where i work, and bought some ground loop boxes, i think they were called iso boxes?? but they are like 10 bucks. you plug your rca's into them, then the box has a set of rca's that plug into your amp. problem solved on mine for the whining noise. on my driver side speaker, it did not get any sound at all. i just spliced into the passenger and that worked. i know i know, its cheap but i just wanted to make sure everything worked on the stereo. hope it helps.

 

As far as your 4th speaker not working I would imagine it to be a loose wire as stated earlier, or a broken RCA, damaged during/before install. The whine can also come from running the RCA's on the same side of the car as the power for the amp. If they cross, no matter how good your ground is you will usually get engine noise. I ran my RCA's on the same side as power to my car and this whine you refer to reared his ugly head in my car. So I took another couple of hours and ran it on the other side. good luck, I hope I was able to help.