Weird noise in rear speakers

[davidha91]

Hey guys,

I have two 6inch speakers in the rear and they work fine when car is on acc but when car is running, this werid sound comes on. The sound goes according to my revs as well. The sounds goes higher when i rev and low when i don't rev. Need help fixing it.

Cheers

[2MPRS]

this is a very common problem when installing speakers.
if the speakers are connected to the headunit make sure the wires arent touching and to be safe just run new wires all together.
if the back speakers are amped try changing the earth point of the amp or try new rca cables

[boy180]

correcT! if u have a amp run to the back, u might wanna run the rca and power terminals opposite sides of each other.. run a fat cable for earthing =)

[HKS200]

bad ground, thats the only answer

[dogcrapau]

do you have an amplifier that is powering the rear?
i would bet you do.
if so run the power cable and the RCA cable with at least a 0,5m distance a part.. ideally youd run the RCA on one side of the car and the powers on the side of the car or down the centre.

the reason for this is RCA= signals and electricity cable= power..
the whining your hearing is basically proportional to the alternator..
when you rev up.. you spin the alternator more, you get more charge. This charge is in the power cable, and when it runs through a cable a electric field is formed, NOW if you have a signal (RCA) cable running side by side.. it will pick it up and translate the sound to the speakers henc eyou hear whining or static that is proportional to your revs.
When the car is on acc (car is off) it should be fine because the alternator doesnt spin.

This is often the biggest cause of engine whine.

there are also as others have mentioned.. bad grounds, but if i had to make a bet im sure its the cabling so have a look there.

i have worked in car audio and car electronics for 10 years, pm me if you need further help or perhaps bring it around to get it checked.