I just got my subwoofers and amp installed yesterday, and I think there maybe something wrong. The first time I turned the car off, 1 second later there was a loud "BOOM" and at first I thought I blew my subwoofers! It scared the sh!t out of me! Now everytime I turn off the car is does that, and sometimes when I forget about it , it still can catch me by surprise. I hope this is fixable and not normal!