I have Mach 460 System, but it is noisy. It does the following: Pops when first touch brake pedal; constant hum or buzz that doesn't change with RPM, and a whine that does change. Replaced the two radio capacitors on engine and it improved for awhile but returned. A local Dealer's occasional "Radio Guy" said it is a bad ground somewhere. I added engine to body ground wires with no success. He says connect ALL of the component grounds (amps and head unit) together. Anyone familiar with this that can help?

 

I am having the same problem...drives me nuts

 

he is right, but what he meant was that it was probably a bad ground on the radio, or amplifiers. Start by pulling pullin and tuggin on the hanresses going to the amps in the trunk with the system on and see if the noise changes. Nest take the deck out of the dash and see if the noise changes when you gently tug and pull on the harness going to the radio. If that doesn't work then try to gently tap on the radio first with your fingers, then a little heavier with your knuckles. Again do this with the radio on and see if the noise changes and if still nothing then do the same on the amp located below the radio.