whinig noice, bad ground?

I did a search but couldnt fine what i was looking for, I had alpine head unit iinstalled a yr ago and have been liiving with a whining noice that get louder with thr increase of RPMs or pressing a power button such holding down the power window button. I've kinda got use to it but im looking to sell and upgrade mustangs and i want everything to be right when i sell it. I have hear two different reasons why this may be happeneing, a bad ground or i need a filter? ( the last siggestion came from a stereo store, same ones who installed the unit so im not really trusting them.

thanks for any help

Are you using aftermarket amps also in conjunction with the Aftermarket head unit?

no

If you are still using the Mach amplifiers, then you need to have a line level adjuster installed to lower the signal going to the factory amps. This is a common problem with some Mustangs that have a aftermarket stereo installed using the factory Mach amps. The line level adjuster is simply a box that is wired in between the new deck and the factory speaker wires, and they usually have 4 gain adjustment knobs to dial in the output.

thanks.
I was able to get it all sorted out the other day.
now all i nee to fix is the abs light problem which i hop is just the sensor/module