I am about to put dynamat (actually fatmat) in my roadster and had some potentially stupid questions:

(1) Do I just put the stuff all over the door? Do I need to worry about obstructing any bolts?

(2) Do I put some in the speaker "well" (the area you can access when the speaker is removed- where the window glass is)?

(3) If I have extra, does it help to put 2-3 layers on?

Thanks.

 

i just threw mine up on the door over the bolts and stuff....and put some in teh speaker wells any where that could possibly have vibration or rattle...dunno bout 2 or three layers though

 

1) Since dynamat type products are used to reduce vibration, you want to cover a good part of the inner metal panel of the door. But you don't necessarily need to cover every inch. I ended up covering most of the bolts. You should punch holes for the door trim panel clips with something like a screwdriver so you can put back the door more easily.

You should also consider placing dynamat on the back of the plastic door panels. Tap on the door trim panel, and dynamat any resonating areas. Usually about a 1/3 of the surface is sufficient. Install the panel and test the door. You can then also slam the door and listen for any rattles.

2) You should also place some dynamat via the speaker hole in the area directly behind the woofer magnet. Ususally one layer of dynamat is sufficient.

3) However, if there is an area where there is a lot of resonance (again test by tapping with your hand), you can add a second layer.

Remember, dynamat is not really for noise reduction. If you want to reduce the outside road noise, put a layer of barrier material (e.g. neoprene) and noise absorptive material (e.g. acoustic foam) as well in areas that can fit. I learned a lot about this from dannichols is our resident noise reduction guru who is extremely helpful and has done tons of research for us. Good luck on your install!!!

 

I cut mine so that all parts could be removed and all bolts could still be accessed.

The window motors in Zs have a reputation for going haywire and the last thing I wanted was the dealer to charge me for doing warranty work.

Chris

 

Sound and noise are both vibrations - they'er the same freqency of energy - one in the gas of air, the other in the solids of our doors and door panels.

Ideally you'd pour concrete into the doors to increase the mass. That's probably a non-starter for most of us.

Mass like fatmat makes it harder for the vibrating gas (sound) to vibrate the item. Accoustic foams are designed for absorbing higher end frequencies by causing them to bounce around warming (ever ever so slightly) the foam.

The best results would come from layers of fatmat adding weight and some foam layer on top to break up the reflections. Road noise tends to be low frequencies (sounds like something fun to measure with my RTA) and rattles and vibrations are low just by their nature.