when i turn on my system i hear a zzzzzzzzzzzzz and i turned on my dome light and my system popped wtf is that???i asked the guy whats that and he said lower my volume on my radio <<---nuts) see man ny cant do nuthin-and i did install in a shop i hate ny lol
ground loop. probably have speaker or power lines for the stereo run close to an ignition coil line or crossover network. It could also be a bad ground point or loose ground, or the amp gains could be set too high causing feedback. Check wiring for the amp(s), check the groound for the head unit. make a new ground for it. don't use the factory harness ground wire (I hate those). Make sure the amp gains aren't set too high, as this causes both clipping and feedback which introduce this sort of noise. the RCA interconnect and power and speaker wiring routing can be trickier to troubleshoot, although the fastest way to do it is by testing the RCAs first, then speaker wires, then finally if you have to, power and ground by running new lines between radio and amps, and amps to speakers (not under carpet, just loosely and not near anything else) Lastly, check the amp ground points. sand off any paint where the amps are grounded. do not use seat bolt posts as ground points, and make sure you have sufficient wire gauge for power and ground, and the ground is to BARE metal with a solid connection.