my trunk rattles pretty bad and im thinking about dynamating the whole trunk. Ive never done anything like that before, and dont know anyone whos worked with dynamat Where are good places to put it, how hard is it to do? how much will I need to do the whole trunk? its mostly the hatch that rattles. any help would be great. thanks

damping the trunk will not stop rattles. well...it will stop some of them, but the only way to truely eliminate them is to place some kind of barrier (felt, carpet, damnpin material, etc..) at the point of vibration that causes the rattling. in other words, if the passengers side trunk panel was vibrating, you would want to run some kind of "bead" of material between it and wheatever it is up against to keep it from making a rattling sound.

that being said..it is possible to reduce vibration of the panel by changing its resonent frequency. if you were to couple a bit of damping material to the back of the panel, it might not vibrate anymore due to the fact that it does not "respond" to audible frequencies. its really hard to predict this, however.

the *true* use of damping material relates to the above, you would use it to keep sympathetic vibrations from occuring in things like floors and firewalls, so that the outside sound from tires/etc. will not be transduced by the metal and in turn transfered into sound waves inside the cabin of the car. its also usefull in keeping panels on the inside of the car from vibrating, which because of thermodynamics will rob your system of its overall output (if energy from the system is being used to vibrate panels, its no being used to get sound to your ears).

back to the original question, i would suggest putting a portion roughtly 1 sq. ft. in the middle of each of the trunk panels, and using what you have left over to line as much of the trunk floor/walls as possible. its better to spread it out than concentrate it into one location.

edit: guess i should mention that this perspective if for someone who does not wich to spend exorbinate amounts on damping material, and does not wish to spend tons of time getting everything just right.

yup ^^^ what he said.

and you don't need to cover every square inch of a panel with dynamat to lower it's resonant frequency.

check out foambymail.com. that's where I got some Volara foam (cheapest I could find closed cell foam) which I put underneath all the panels to prevent rattling. worked like a charm!