This is a long going problem with some recent progress.... please read.

Dmhines really helped me out with the initial "POP!" I got when turning on my car. It was due to the new aftermarket headunit sending 12v to turn on the factor Shaker1000 amp. He told me how to install a +5v regulator from Radio Shack to eliminate the problem.

I installed the regular on the metal framework surrounding the radio behind the dash with a machine screw and lock washer. I found a good ground for the regulator and wired up the +5v remote wire from the headunit.

Now when I turn on the car, the initial pop is gone. However, I get popping while music is playing. It's only on bassy notes when the volume is up more than halfway. I actually had to go in and turn off Loudness and turn the bass way down. Even so, it still does it if I have it too loud.

It never did this until after I installed the +5v regulator. Before installing the +5v regulator, I only got the pop when the headunit turned on.

I really want to get this fixed. It's driving me absolutely crazy. The headunit is a Premier 9800.