Just finished install my new stereo. Pioneer Avic D3, Rockford mono, and 4chan amps in the trunk, all new speakers, and two 10in rockford subs.

Works great, except for one annoying thing that I've never had happen before. When nothing is playing, the speakers buzz, depending on RPMs. The higher the RPM, the louder the buzzing. I've installed systems in several other cars, and never had a problem like this. I'm sure someone has a good idea on what the cause might be.

 

You have a ground problem somewhere in your system......best way to eliminate the "ground loop" problem is to make sure all the grounds that have anything to do with the stereo are connected to the same spot in the vehicle.....this means the ground for the deck.....the grounds for the amps and all other components....crossovers/equalizers etc...the other thing that can cause the buzz is the radio antenna...this grounds to the vehicle too and can often be a pain in the ass when it comes to ground problems.......other people will also call this problem "alternator whine".....do some searching and you will find that what i have suggested will fix 99% of these problems.......and in my opinion, stay away from ground loop isolators...they dont work worth a crap........Good luck......Later

 

If what highrider suggested doesn't work (it should), you may try this.

http://www.caraudio.com/forum/showthread.php?t=147694

This happened with my Pioneer head unit. It's actually rather common with them. I spent almost 3 days ripping my system apart and putting it back together before I stumbled across that thread. Hope that helps you.

 

yup pioneers blow pretty easy but its a simple fix with some solder and a bit of wire. The car audio forum is the ghetto way of doing it... If you soder a small metal wire (not audio wire) to the chassis it will fix that problem.

Oh ya you can test it before you do all that by touching a wire to the shield of the rca and the HU chassis

 

I'll have to try that, all the other grounds are good. Never seen this problem before, and I've always used Pioneer HUs.

 

I had this same problem a few months back, I sent my Pioneer H/U in for repair and it did nothing. It ended up being my amp, I had to RMA it.

 

The ground problem is with the Amp, and I made the buzzing better by moving the ground connection further from the battery. I think I may be able to remove it completely if I pick a place to ground that isn't in the trunk.

 

try running a 10 awg wire (or 8) from your Head unit to the same point your amp is grounded (or just a better ground point)...I'm guessing the Radio ground is not very good and the Radio is grounding through the RCA's to the Amp causing your hum.. The reason it "gets better" when you move the amp ground away from the Battery is because your makeing the amp's ground worse. The electricity wants to take the lowest resistance path....(Lost yet?)