Im sure its already on here somewhere...and i think ive read about it before..but i cant seem to find it...

Every time i close my front doors on my 06 CC it sounds like your slamming the piss outta them. dont matter how easy you try to close em it sounds like your tryin to knock em thru the other side. and when your drivin it sounds like the inside of the doors are rattling. PLEASE HELP ME BEFORE I GO NUTS

The front door speaker might be loose. Pull the door panel and take a look at them. It's a common problem.