Hi, I'm posting for a friend. He has the Mach 460 and sometimes when he turns on his car there is this really bassy, loud noise that comes out of his speakers. It's not volume dependant, because even when his head unit was turned all the way down it'd still be very loud. It's a problem that comes and goes, and it's real random. It will be good for a month and then it will be a problem again for about 3 hours, then it will just fix itself and repeat the cycle. What's causing this and how can he fix it?

 

If you were talking about an aftermarket system I would say it sounds like the RCA's from the head unit to the amp are loose, I'm not exactly sure how the mach system is wired but a good place to start would be where the wiring from the head unit runs into the amp. If it is a bassy sound it is probably where the wiring runs into the sub amp. Try to notice if it happens more when you are on a slightly bumpy road (small sharp bumps will make it worse if the problem is loose wiring).