Car Stereos: speaker noises, 1993 buick centry, ground wires

Question
1993 buick centry. speaker noise is a deep sound that goes up and down with the rpm even with the volume turned down. un hooked the alt wires going in and coming out.no change.the car is all factory. its not pecking sound more of a hum.checked plug wires at night no sparks.pluges are not very old. this started all of a sudden.though it might be a ground wire problem. just need to know where to start. thanks and have a nice day.

Answer
Hi Henry,

You're right, it's almost certainly a ground looping issue.  In a 16 year old car, some of your grounds and copper starts to corrode and not make such a good connection anymore.

You might want to start in the engine bay, and check your ground wires  Look for corrosion, and bad terminals, and replace them.

Justin