Originally Posted by 2003SonicBlue
Where the rear speakers are, I put two 6x9s in and I have 2 12" subwoofers right underneath them it's not the subs. Although I am getting a new enclosure for them so it's made just for the mustang. Rattle has gotten very bad lately, I know I need to do my doors trunk and that little area for back speakers
Sounds like the rear deck covering is banging against the metal area where the speakers are held in. Dynamat my not help that unless you put it in between the rear deck and its cover. Does that make sense?
I did my trunklid, trunk floor, doors, and passenger area floor. I pulled out the system before I did this, I just did mine to get rid of some road noise. Works great though. You don't need to cover every square inch, that would be expensive and add a bunch of extra weight.