I recently bought subs and they rattle the hatch to hell. So now i just got 36 sq.ft of fatmat and was wondering if it would be better to put it on the metal of the car or stick it oon the backing of the plastic panels that form the truck/hatch area. thanks

apply it to the back of the plastic to minimize its sympathetic resonation with the bass, and then use it (or pieces of felt, carpet, etc.) inbetween seems that cause the actual rattling noise. the imporant thing to remember that sound damping material doesnt stop rattles just from application, it requires a bit more detective work to get them minimized. when my subs were in the trunk, i noticed that the plasit panels on the underside of the trunk lid rattled like crazy, so i used thin strips of grey carpet (to match the interior) wedged into the seams to stop the noise. the same technique was eventually used on every seam of every panel in the trunk, and it worked like a charm.

The best place to install the sound deadener is on the actual body panels. Remove all of the panel pieces in the trunk and install the deadener on every piece of metal you can touch.

Reach through the holes in the inner panels and place the deadener on the exterior body panels. This will decrease the resonance level of the entire vehicle. Once this is done, you will not have to worry about the plastic panels, because they only resonate because of the metal they are attached to.

Good luck to ya!

uh-oh, im going to have to disagree with you audiophyl. explain how damping the metal will decrease the resonance of the plastic panels?

just playing devils advocate here...im a firm believer that damping products are used incorrectly 90% of the time, and im looking for varied opinions. no matter what you rock. ;)

and BTW...you only have 60 somthing posts here? you need to start posting more.

The frequency of our vehicles is between 56-57 hz. How is this estabolished you ask? Place a single 10" sub in a sealed enclosure into the hatch area of the car. Play test tones, utilize a meter, and record the highest spl. That is the resonate frequency of the vehicle. Next, you want to build an enclosure that hits at 56-57 hz. Do this and you will get impressive numbers in spl competitions.

Since the highest spl is at 56-57 hz, that estabolishes the resonate frequency of the vehicle. With this in mind, what happens when you install sound deadening materials into the vehicle. You change the resonate frequency of the vehicle. What is actually causing the resonating you ask? The flex in the metal of the body panels.

This flex in the body panels is what leads to the vibrations in the vehicles. Think about it. If you have a huge sheet of metal and start to shake it...what happens. The panel vibrates and "thunder" is heard. Apply a piece of plastic to the panel and what happens...the same thing. If you were to apply sound deadening to the metal, even with the plastic attached, the "thunder" will be decreased. It's a simple matter of physics.

Oh yeah, you mentioned that I only have 60 posts. You're right...I'm new to 2GNT.