stereo makes a whirring noise

[elmercc]

My car did this, and I finally took it to a sound shop and they found out the factory amp in the car was going bad, rewired it to bypass the built in factory amp and voila...no more supercharger whine.

[CallmasterIV]

throw in a filter. usually a coil.

[StereoInstaller1]

Probably 20 year old Fosgates are finally crapping out. Those model numbers came in 3 different chassis: "Tombstone" or silver or gold "Rocketship". Which are yours?

[RwMystery]

Probably RCAs next to power like Darrenforeal said.

[zshopa]

definately check grounds at both amps and at the headunit! i would take where the amps are grounded and make sure that there is plenty of metal to metal contact (not painted) you can sand it a little bolt it back up and then spray paint it if you are worried about rust.

[darrenforeal]

Yes it's been doing this since I've owned the car. Basically my stereo sounds like it has its own little supercharger. The pitch mirrors my RPMs too. I have one Fosgate 600a4 amp powering the speakers and a Fosgate 250a2 amp for the subs which are 2 8" MTX Thunder6000s and an Alpine CD changer that doesn't work lol and a Alpine deck. My only guess is the amp doesn't have a good ground?

yeah alternator whine. Check for a ground loop. Also sometimes having the RCAs running with the power cables can cause noise interference.

[lga714]

Yes it's been doing this since I've owned the car. Basically my stereo sounds like it has its own little supercharger. The pitch mirrors my RPMs too. I have one Fosgate 600a4 amp powering the speakers and a Fosgate 250a2 amp for the subs which are 2 8" MTX Thunder6000s and an Alpine CD changer that doesn't work lol and a Alpine deck. My only guess is the amp doesn't have a good ground?