popping sound in rear speakers/sub box

[spongebob915]

Anybody have this problem. I have the volume at maybe 25% and it sounds as if I have a blown speaker. Sometimes it does not do it right away and of course at the dealer this morning never did it. They did do a sync update that's it.

 

[WHY NOT]

My factory sub would pop/thump after I turned the truck off and opened up the door. I put an aftermarket one and it still does it, cant figure it out.