Contour Enthusiasts Group Archives Forums Modifications Audio Dyna mat

Hello, I have a pretty loud system in my car, (Rockford 12 hx2 in a vented box with a Rockford BD 500 amp). Anyways, my contours trunk rattles terribly when the sub is going, you can hear it while going down the street. would having Dynamat put in my car really help to stop the rattling? what other bennefits does Dyna mat provide? any input would be much appreciated, thanks1

my trunk used to rattle pretty badly, and i have coated it with dynamat, all over the inside of the trunk, like 3-400$ worth and i guess it helped. you cant hear the rattle from inside, but theres still some if your standing outside the trunk. downside: dynamat is pretty expensive, i hear this stuff, b-quiet , works pretty well too. so you may want to try that.
matt

Dynamat and the like work to keep metal from transmitting sound, especially resonance.
It won't stop rattles. You need to find the source of the rattle and tighten it up or damp it out. There are 4 areas that rattle like crazy on our cars, license plate, the fuel vapor cannister mounted under the car to the spare tire well, the rear bumper cover, and the air vents to the trunk.

Fixes:
license plate: pull it off and put that foam insaltion tape on the back of it and screw it back on using all four bolt holes.

fuel vapor cannister: tie strap all wires and hoses snug to something solid. In fact, DO THAT for all wires, tubes, cables, etc. that move easily by hand both inside and outside the trunk.

The bumper cover: pull it off, clean it up and apply the foam tape to all areas where it may come in close contact with the plastic bumper frame underneath. While its off, spray rubberized undercoating to the whole underside of the rear of the car, not covering things you shouldn't like fuel connections and mufflers, etc.

The air vents. They are one-way rubber flapper valves that slap against the opening as the speaker moves in and out. You can only pull them off to help.

Use the dynamat or similar product on the inside of the car in areas where you can tap the metal and it sounds kind of 'tinny'. Usually wide sections of sheet metal with no bracing. You only need a few inches by a few inches per section to stop the metal from resonating.

Do all of the above to the doors if you have them off, including some pieces of dynamat onthe metal and finish by spraying the rubber coating inside the door shell. You will have to let it set for an hour and then close up the panels so the smell goes away and it sets good.

After that it should be a hell of a lot quieter.

materials:
1 roll of thick foam weatherstip tape (hardware store)
1 roll of dynamat (audio store)
2 cans of rubberized undercoating (auto store)
1 big bag or can of tie straps (auto/hardware store)

Total cost ~ $50.00

This will work wonders, I promise and it is sooo worth the effort.

And also the rear package tray. Remove from inside, add 1/2" carpet padding, replace deck.