So we all know that if you buy this sound dampening product for your vehicle, that you install a single layer if you are lining your trunk or floorpan. So when I was browsing YouTube for videos showing various install techniques, I saw this one guy who was applying one layer to the inside of the door panel of his SUV and on the metal mounting surface.

Now I had assumed that to get the best sound on a Mustang, you would pull off the panel, remove the vapor barrier, and the apply the product to the door skin, behind the inner door shell, that the vapor barrier sticks to...? I had thought that this product 'warms up' the sound you get from expensive after market high power amp driven speakers... Therefor you would install it behind your speaker cones to give a better surface for the sound waves to reflect/reverberate.

I can understand the guy doing the install on the SUV panels intended purpose was to reduce buzzing and rattles. That's fine for what he wanted, but I want the best possible enclosure when I install my GT Premium panels on my Boss. I have 25sq ft, so that should be enough for 2 layers for each door.

My question is for those who have done this before or received advice from professional installers, what surface(s) did they apply sound dampening to? Inside of outer door skin, outside of inner door skin, and/or backside of door trim panel?

 

The sound damping material that is most common is the foil backed butyl material that is designed to reduce vibration and resonance of the panels. applying it to the inner and outer door skins and the back of the door panels is to add mass to the metal/panel in order to make the panel less likely to vibrate or ring. If you knock on the metal you may hear it ring or vibrate, once you apply the damping to the panel you will notice that you get more of a thud. You're going for that thud when you knock on the panel to avoid the vibrations and rattling. It will help with your sound, but it will not solve all of the problems that you can get when looking for better sound.

I personally applied damping material to the inner and outer door skins of my mustang, and to the back of the door panel. It has made a big difference, but i went a step further and got some closed cell foam to isolate the door panel from the inner door skin as much as possible. This should help reduce rattles even further. Now when i knock on the door, and even close the door, i get more of that 'thud' sound that german cars are known for.

Good luck with your project. One last thing. Make sure you clean the surface and get a roller or something to help you adhere the material to the door. A heat gun can help with getting things to stick even better.

 

I had a good shop do my Dynomat install, and after a long discussion I went with their recommendation and put the Dynomat on the actual metal door, not the removable panel. Their point was that Dynomat only dampens vibrations, so it is far more effective on the metal panels, which will vibrate much more than the panels. It also greatly dampens window vibrations with the windows down; since I ride with the windows down most of the time, this is a big help. Not to mention vibrations from the window motors, tracks, etc.

When I knock on the door from the outside, there is a slight thud and absolutely no rattles.