First off I want to start this by saying that I have pulled this information from a guy on a website that has truly gone the whole nine yards and then some, in gathering info for sound dampening. I will make a major post for the info that I personally thought would be relevent.

Also I want it to be known that I am copying and pasting this info so that you don't have to read through the whole thing like I did.

Sound deadening is the first, most basic step toward controlling vehicle acoustics.

(Web) There are two general classes of deadening/damping products. Liquid deadeners can be sprayed, brushed or applied by trowel, depending on formulation. In most cases, these take some considerable time to apply. They require several layers, with curing time between applications. Since I don't have a garage and need to use my car every day, liquid products didn't seem like a good choice for me.

The second and most popular group of products are the self adhesive mats - generally a thin layer of rubberized asphalt and/or Butyl compound with a constraining layer of aluminum foil on the exposed side and release paper protecting the adhesive before installation. These are the products I will try to evaluate through a few basic tests and some observations.

In the world of automotive acoustic enhancement there is a product whose name is synonymous with the entire category. Much as Kleenex is used to describe all facial tissues, Dynamat, manufactured by Dynamic Control of North America, Incorporated in Hamilton, Ohio.

(Me) Dynamat is definitley one of the more expensive name brands out there. I have used both FatMat and Dynamat. Trust me, they are different. Dynamt works better all around. But, if you are looking for a cheaper alternative and aren't going to be in competition, I would just get FatMat.

(Web) There are plenty of recommendations out there but I found it difficult to determine which were based on solid reasoning and which had a less useful motivation. There really aren't a lot of people with significant experience with a range of products. The products change often. If you buy them for your own use, that will probably be only once every few years. If you are a professional installer, you are probably locked into one product. This isn't like speakers that you can change on a whim. If it works, it is there for good.

The basic function of these products is to:

-Add mass to panels to move resonance out of the audible range
-Reduce vibration through viscoelastic damping
-Reinforce panels to prevent flexing when subjected to sound pressure
-Act as a barrier to the transmission of unwanted sound (noise)

There are two basic concepts that need to be addressed. First, reduce the level of noise coming from outside the passenger compartment. This is the noise "floor" with which the sounds you want to hear must compete. Conversation or your audio system must be loud enough to be heard above this noise level.

Second, control the reflections, resonances and rattles that are generated by the the noises comprising the noise floor and your sound system itself.


(Me) This is for the basic info portion of the "sound dampening experience." Now onto the trials and tribulations and installations of different products. Along with some pricing to boot.

Is sound deadening mat the best way to treat rattles? Maybe. A rattle is the result of two solid objects hitting each other. It is possible that applying one of these products will stop a rattle, either by immobilizing the two solid objects, or by reducing the vibrations that are causing them to hit each other in the first place.

An effective approach is to identify the source of rattles and treat them prior to installing the mat. Make sure all parts are tightened down. Wrap wires in foam tape at the point where they contact sheet metal. Rear license plates and spoilers are notorious source of rattles.

(Me) In order to achieve that maximum "luxury car" feel or the highest SPL levels, you need to knock out all other interferances with you car. Sound dampening will help to stop outside noise and retain interior sound. (Yes there is a difference between noise and sound)

Ultimate Sound Quality
Pursuing Sound Quality can be an obsession. Selecting the finest system components and installing them perfectly will never get you to your objective if you don't pay at least as much attention to the acoustics of the vehicle.

Start with the panels we addressed in the SPL section, add noise reduction and possibly extra absorbers and you will be well on your way to a great SQ setup. By reducing sound energy loss, blocking noise from the outside and absorbing distortion inducing reflections inside the vehicle, you are cleaning up the sound you hear and lowering the noise floor with which the sounds you want to hear have to compete - any sound system will sound better and use less power. Moving on....

Basic Application Procedure
The specifics of each area are slightly different, but the basic process is the same. Remove any trim, seats, carpeting, or whatever is covering the sheet metal or plastic you want to treat. Vacuum out any dirt and dust and then wipe the area with denatured alcohol. Acetone will work, but it will remove paint, so be careful. You now have a dirt and grease free surface ready to take some sound deadener.

Start with any easy - flat, large area like part of your trunk. Cut off a piece about 8" long - I prefer a pair of heavy shears, but most people like a utility knife. With a little practice you will be able to work with pieces a foot or more long.

Peel the release paper off the first inch or so and fold it back. Now you have a piece of mat with an inch of adhesive exposed and the rest still covered with the release paper. Ready, aim, fire. Line the piece up and press the exposed adhesive down on the surface. The mat is now positioned where you want it and if not, you will still be able to get it off. Good spot? OK, start pulling the release paper down the length of the mat, pressing the exposed adhesive onto the surface as you go. Voila! First piece down. Do that a few hundred more times and you are done.

You want to use the largest piece you can for each application - but not too big. You will quickly learn what too big is, because in your impatience and growing confidence, you will finally get to the point where you exceed your capabilities and the laws of physics. You will lose control and get a bubble or a fold or something you didn't intend. No problem, take your knife and cut the bubble or fold out, press it down and all will be well. You want to have perfect contact between the mat and the surface you are attaching it to. Your utility knife and an X-Acto knife will be your friends.

While you don't need a heat gun or a roller, they may help. If you are using Peel & Seal, or one of the asphalt mats sold for automotive use, ignore the advice of the seller. If you are wearing anything heavier than a t-shirt, you must use something to warm the substrate, warm the mat and then warm the installed mat before you roll it. Be careful not to melt the adhesive or you might be accelerating the deterioration of the asphalt. At any temperature warming to about 120°F will improve the adhesion of an asphalt product. Butyl adhesives are no where near as tricky. If they are flexible enough to install, they will stick. I got a nice roller at Home Depot for wallpaper - rubber handle, plastic roller, $5. Really helps for pressing down on flat areas, and it gives you something to do while you figure out where to go next, so you don't just sit there looking dazed.

As you apply sound deadener, rap on the panel with your knuckles or a small rubber mallet. You will be able to hear the change in resonance. After you apply a layer, tap some more. This will help you determine where you need to add layers. Tap, apply, tap apply, until you are satisfied with the result.

(Me) ---Here is part of the website so that you can see some different materials with different variations and the effect of each one. Sound Deadener Showdown