I just bought 100sqft of fatmat from ebay and two cans of the dynamax spray in liner. Where are the best places to put the fatmat and where should I spray the cans at? I want my car to be as quiet as a caddilac. So I know you guys can help me out here.

>I just bought 100sqft of fatmat from ebay and two cans of the
>dynamax spray in liner. Where are the best places to put the
>fatmat and where should I spray the cans at? I want my car to
>be as quiet as a caddilac. So I know you guys can help me out
>here.


then buy an assload more than what you have if you want it to be as quiet as a caddy.

There is something (can't remember what it's called) that is a harmonic barrier material. Basically thick foam/rubber that is imbedded with certain metals that you cut to size and lay under your carpet. That's what will really make your car quiet.

Other than that here's what I've done:

Take off headliner. Fill all frame rails with expanding foam and do 2 layers of dynomat on sheetmetal roof, then glueinsulating foam back on and replace headliner.

Remove all rear interior panels and dynomat floor and walls. Then fill all empty cavities with expanding foam.

Remove door panels and completely cover the door with dynomat, including all exterior sheetmetal I could reach inside the door.

Pull up front carpet and put the remainder of what I had on the floor.


My car is quieter...but quiet like a Caddy? LOL....hell no, and I have about twice what you have in my car. And as soon as I put my Greddy SP exhaust on all of my quieting went out the window. I'd hate to hear my car with no dynomat or fill foam.


If your serious about it get that harmonic barrier stuff, get thicker carpet, do two layers of dynomat on the floors, use a paint brush and paint in truck bedliner stuff on all areas you can't put dynomat (or fatmat, it's the same thing).


Oh, and don't use the spray cans of sound deadener. They don't do shit other than get shit all over the place and basically piss you off. Brush in is the way to go.

So there is no where I can put the spray cans of dynamat. That sux.

>So there is no where I can put the spray cans of dynamat.
>That sux.


Well you can use it you just have to get a lot of plastic sheeting and tape and just tape off EVERYTHING YOU DON'T WANT STUFF ON!

That crap splatters and goes all over the place....and it really doesn't help that much.

miller take a ride in mine (no sound dead in the rear or on the drivers side ... no rugs ... no rear ... lol a rock going under my car is just hilarious !~!

I also heard you get the most noise from the doors and the roof, is that true? Also there is this annoying rattle coming from the Center to Passgenger side of the Dash. Is there a way I can get rid of that or can I take off the dash and put fatmat behind it? I apreciate your help, a_miller_76.

what he was talking about above was loaded barium vinyl, layered with a closed cell foam to act as a decoupler. that is a sound blocker (barrier), as opposed to a sound deadener - like what dynamat/brown bread are. cascade audio sells sound blockers like v3, v4. but it's freakin expensive. if you are resourceful, you make your own version of the same type of blocker, for 1/15 of the price

So what does this fatmat stuff actually do then?

>So what does this fatmat stuff actually do then?


It changes the weight of the metal and it's harmonic vibration characteristics so that it vibrates at a much lower tone.

Tell me if this is a good idea. Put two layers of fatmat on the roof, one on each door, one on the flore, and whatevers left around the backseat panel and speaker area. Then use my two cans of dynamat spray and do the trunk and hatchlid also with the PaintBrush on truck bedliner back there too.

Rule of thumb: Anywhere you thump and there is excess vibration, layer that shit. I'll post the pics of my bulk dynamat install as soon as I can get my damn scanner working.

Make sure you get the headliner, hatchlid, and trunk the best, as they are the most problematic in our cars.

Does anybody know how to get rid of that annoying rattle coming from the passanger side of the dash?

Will putting fatmat behind the dash solve my problem? How hard is it to take out the dash, anyways?

>Will putting fatmat behind the dash solve my problem? How
>hard is it to take out the dash, anyways?


Dynamat or fatmat or any other harmonic vibration dampening material will never solve any "rattles". If you have a rattle best thing to do is find it and fix it.

What fatmat does is lower the hum of the metal in your car. Best way to describe it is if you tape metal it will make a "ping" type noise...but if it has fatmat or dynamat on it it will make a "thud" noise instead.

^^^amen.

by damping a piece of material, you lower its resonant frequency, meaning it will not vibrate AS MUCH given the same listening condition. this does not, however, mean that the vibration will be totally eliminated, and you MAY still get rattles. to eliminate rattles, you dont need any damping material at all. rattles are a result of two parts touching in a certain frequency cycle. if you add a barrier between the offending pieces, you eliminate the rattle. for example: if your rear hatch plastic pieces are rattling agains the metal frame of the hatch, you could add a felt or carpet (etc..) barrier between the pieces to keep them from touching. you COULD get the same results by damping the piece, but you would not be guaranteed to be free of rattles.

the main point of dynamat et al. is to eliminate transduced road and wind noise through the metal frame of the car. as your tires roll on the pavement, the create noise, that pressure wave hits the metal of your car, and the metal vibrates, acting as a transducer to send a small pressure wave into the cabin. by adding mas to the panel (wether its dynamat, fatmat, clay, etc, etc, etc..), you eliminate that sympathetic vibration and reduce the outsude noise. it also works the opposite way...if youve got a big system, the metal can vibrate in responce to the internal pressure wave in the car, transducing that energy to the outiside, and in essence, wasting energy.

now thats not to say that you are wasting damping material by applying it to interior pieces (plastic or whatever). by reducing the resonant freq. of those pieces, they dont move as much in responce to the pressure wave. this means that more energy reaches your ears, and is not wasted on making the panel move. that gets me back to my main point: although damping material may get rid of SOME of the vibration, it must be applied exponentially to create a completely non-resonant panel. you MAY get rid of a rattle by apply it, and you will definatly save some energy by doing it, but dont expect it to be the end-all cure to rattles. only a barrier between the offending pieces of material will do that.

edit: to answer the original question: the best results will be seen by applying the dampner to the doors, the transmission hump, and the firewall/footwells. most of the noise is going to come from the floor of the car, so anywhre under the carpet is a good idea.

Thanks, thats the answer I've been looking for.

i hear A LOT of road noise coming from the area right around the rear speakers, is that a problem in your alls cars too or is mine just a homo?

^^^that is very plausible, as you will probably get a lot of road noise via the wheel wells. i never damped mine because i had a huge wall in the rear seat are for my subs, but i wouldnt doubt that its a problem.