Originally Posted by david.avrahami@ (Post 7364795)

Johnny042, what do you mean by the rear compartment of the car? are you referring to the engine compartment fire wall? or the back seats area?

Originally Posted by nineball (Post 7363384)

to really "block" noise it is a 3 step solution.

1. apply a cld (constrained layer damper). this is what dynamat xtreme and second skin damplifier / damplifier pro is: a butyl-based rubber with a layer of adhesive on one side and a layer of aluminum on the other. the adhesive side is applied directly to the metal panel, the butyl converts vibrations into low level heat which is then dissipated by the aluminum. you only need 25-40% coverage on large flat panels for this to be 100% effective. there is no need to do 100% coverage as you are just wasting time, effort and product (money).

2. apply a ccf (closed-cell foam) decoupler. most people use ensolite, or a similar closed-cell foam product. thickness varies but a minimum is 1/8", up to 1/4" will work as well. this acts as a separator between the cld and mlv and also serves to block some of the spectrum of sound. some come with adhesive applied already but if not something like 3m super90 spray adhesive will do the trick. this needs 100% coverage.

3. the last step, and the one that actually blocks (or repels) the sound is mlv or mass loaded vinyl. the optimal solution for most car applications should weight approx. 1lb/foot, and this needs 100% coverage to be effective. you also need to seal up any seams as noise (like water) will find the path of least resistance. overlapping the mlv and sealing it with a contact cement-type glue is the best method but you can also use a heavy duty tape.

if you have any questions feel free to ask.

ps> applying steps 1 and 2 to the inside of the outer skin and inside of the inner skin of the doors will greatly improve your audio output as well. the cld helps with vibrations caused by the speaker and the ccf absorbs the backwaves of the speaker.
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Originally Posted by RWebb (Post 7368711)

post your location, as the shipping charges for mlv may dictate where you buy it

Originally Posted by Ttownthomas (Post 7368872)

Raleigh nc

After further research I would prefer a ccf + mlv composite.

Originally Posted by nineball (Post 7368904)

install is easier if you do them on their own.

Hang or Secure Barrier Layers (MLV/CCF) | Sound Deadener Showdown

Originally Posted by nineball (Post 7369015)

no, you don't need to glue the ccf or mls. using don's velcro system you don't permanently adhere either to the car. they are just as effective as a floating barrier. the cld does need to go directly on to the metal to be effective.

when installing you want the seams of the mlv to overlap. when the mlv and ccf are one piece that creates an even thicker seam if you will, 1/8" thicker on every seam, thus harder to seal.

http://i50.tinypic.com/4r3zfd.jpg

Originally Posted by Ttownthomas (Post 7369194)

Ohh... I see. So can the ccf pieces simply butt up to eachother and you cover the seams with mlv?

Originally Posted by nineball (Post 7369285)

yep. the ccf is just a decoupler, the mlv is what blocks noise.

Originally Posted by nineball (Post 7369353)

1. probably not. most installs apply the ccf and the mlv to the inside of the outer door skin.

2. for audio reasons. it's called "sealing the door" but no door will ever really be sealed, you will always have the drain holes in the bottom. by covering the holes in the inner skin you form more of a chamber for the door speaker, which improves output especially on the lower end of the spectrum. it's no substitute for having a sub but it will increase your low output.

Originally Posted by RWebb (Post 7369543)

for the parts of the door closest to the occupants, use the heat shrink/moldable stuff by CAE

Automotive Noise Control - Soundproofing

don't forget to dampen the door skin

it will add wt. to your car