Anyone Know of Alternatives to Dynamat
 

I want to put "some" sound padding around my new rear speakers and in the spare tire well and the rear wells. I was planning on using Dynamat but that stuff seems really expensive and I was wondering if anyone knows of a good alternative.

I really don't need too much but Best Buy sells Dynamat for about $40 a square ft and that's a lot - plus, that stuff is fairly heavy and if I can get something fairly light - that would be great. I was also thinking of doing the doors (under the door panels) since I've noticed cold air coming in thru the power mirror switch.

Thanks in advance....................................Vern

you get what you pay for when it comes to stuff like this - as an audio engineer, i can tell you that dynamat extreme is the most effective material i have found in dampening low mid and mid resonance in a car - it will do nothing in low frequencies, and next to nothing in high frequencies - foam, and carpet liner and such do not do the job nearly as well

it is rather hefty, but you have to pick your battles - i am extremely conscious of weight in my car, and have gone to great lengths to remove 240lbs, but i felt the benefits of the dynamat extreme were worth the weight - i have been VERY happy with the results

pretty sure that crutchfield sells the stuff for less

That's all I wanted to know. I like the Dynamat because it's thin and I'm sure it will do a good job - I just thought I would check to see if there are alternatives. I'm definately not going to use anything like foam or carpet padding as I want this to be permenant and factory (looking).

As far as price, I will pay what I need to pay but if I can find it cheaper, that would be great too.

I've used a dual density 3/16" sheet foam called NuPrene on my 951. It's an open and closed cell design and looks like wet suit material with the smooth side out. I glued it to the rear hatch deck, doors, floor, sidewalls, rear seat bucket area (rear seat delete project) and behind my new 6.5" speakers I installed. In areas where I wanted more sound deadening and heat deflection I used a woven fabric mat product with reinforced foil on both sides. Both products are fire resistant and aircraft certified. I did the entire car for the price of doing just the doors alone in DynaMat Extreme. All I can say is I have about the quietest 951 I've ever been in. Now if my singing was only as good as the stereo system it would be perfect. Is it better than Dynamat, I don't know but it sure weighs and costs less.

Vern,
Try calling a building material supplier (not Lowes or H.D.) they should have sound absorbtive rubber sheeting with a high STC rating - it's used between hotel & apartment walls.
Also try California Industrial Rubber 268-7321 they may have a cheaper alternate to dynamat.

i've used just about every material under the sun in building and tuning recording studios (what the heck do you think paid for the toys i've been able to play with?) - different materials have different uses - for cars, no question, it's dynamat extreme - i was not a believer, in fact i was quite skeptical, until i tried it recently

the reason it works so well is because it does something that the other "padding" type materials do not do - it adheres to the metal surface, and creates a static membrane - this kills resonance at the source, rather than just trying to muffle it

this is not the regular dynamat - it's the dynamat extreme - very different animal

I agree with flash968 on the resonance issue. He used Dynamat Extreme, I used something different but the key is using something that follows and bonds to every curve in the metal it attaches to. The original Dynamat, brownbread, or similar bituminous products are very hard to bond to steel and they stink in hot weather. I've also used self-adhesive 50 mil pure butyl rubber tape (Polyken) with foil backing with great results. I'm just cheap and never have the luxury of spending other peoples money so I use alternative products that get me close to the performance of Dynamat Extreme. Any product can cut dB but I prefer ones that gives me more bang for my buck, and DynaMat Extreme is one of the most expensive out there.

I think you should at least post a You-Tube file that we can listen to - LOL

I'm probably not as smart as the other people posting here but working as a Mechanical Engineer for the last 30+ years at least I do have some idea of what is going on with respect to resonance issues. Go to partsexpress.com and check out part # 268-020. It is very similar to the dynamat branded product and will run you $25.90 for a 32"X54" self adhesive sheet. I used it on ALL interior body panels, under the carpets, etc on my 84. I also used part # 268-250 which is a spray. I used it also to further reduce resonance in all ares I could not mat. It is $15.90 a can and well worth it. I used the same approach in my ML55 after I got it back from Renntech a couple months ago. The new intake, exhaust, and stiffer suspension had really made the cabin noisy, the stuff works great.

The stereo in my 84 sounds as good as any I have heard in one of these vehicles and did not cost an arm and a leg. In addition there is nothing visible from the outside. The matting dramatically reduced the noise from the other items also, ie: MSDS headers, no cat, very stiff suspension, 17" wheels, etc.

Steve

For those of you interested I think this article on sound deadening is pretty fair and unbiased...a bit old maybe but accurate. I'm sure there are new products available. I used it a for info a couple years ago on my rear seat delete/package tray project.

http://www.sounddeadenershowdown.com/benefits/

The FatMat Extreme would be my choice today for price and quality.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110199463420&ru=http://search.ebay.com:80/110199463420_W0QQadgroup_idZ286953615QQcreative_id Z731068875QQfclZ4QQfnuZ1QQfsopZ1QQkeywordZsoundQ20 deadenerQQoriginZhttpQ3aQ2fQ2fwwwQ2esounddeadeners howdownQ2ecomQ2fconclusionQ2fQQtestZGadgetQ5fKWQQt ypeZQ7bifsearchQ3asearchQ7dQ7bifcontentQ3acontentQ 7dQQfviZ1

I wouldn't bother, except you do state that you're an engineer, so I am obliged to - you've opened yourself up for it! ;)

It's damping, not dampening.

Damping is done with an absorber - be it a suspension component or Dynamat.

Dampening is done with a watering can.

Neither I nor my car need or want any dampening. ;)

Back on-topic - what about spraying rubber underbody coating? I have heard that this is an effective NVH-reducing technique, particularly for those hard-to-reach-places?

not to argue, but, we are both correct - from the dictionary on my computer:

dampen |ˈdampən|
verb [ trans. ]
1 make slightly wet : the fine rain dampened her face.
2 make less strong or intense : nothing could dampen her enthusiasm.
• reduce the amplitude of (a sound source) : slider switches on the mixers can dampen the drums.

don't ask me why they used the term "slider switches" instead of "fader" or something like that, since a switch is positions, and a slider is gradual

my other dictionaries all concur

i'm going to poke around about the other materials today - i need to do the denali before i go back east in 2 weeks to pick up another 968 i just bought - i want to quiet it down a bit, especially since i am installing the new exhaust this week

moving on

rubber undercoating achieves, albeit to a lesser degree, the same effect through the same means - it creates a membrane that dampens resonance by increasing the energy required to vibrate it - the more you apply, the lower the frequency it will attenuate

Oh, god, don't tell me you're taking advice from Bill Gates??? Eeek!

I stand firm, no pun intended, that my suspension has dampers, not shock absorbers - no matter what you read on the internet! ;)

Yeah, slider switches sounds pretty redundant - hell, ignorant - to me!

Back OT, I wonder where the tradeoff lies in the volume of rubber spray vs. Dynamat or other prepared mat product lies...

i think i missed the joke - bill gates?

Since I am the original poster I think I need to break this up.

And the winner is................................................ .................................................. ...

I'm siding with Flash968 - I've used you advice before and so far, it's been good. I bought some dynamat extreme today at lunch

p.s. I have a dimmer switch in my dining room that uses a sliding switch

lol - no worries - not wanting to be out of the loop, or make a bad decision, i read all the pertinent material - i still went and just bought a bunch more dynamat extreme today myself - doing the entire roof and floor of the denali is only 250 bucks (8 18 x 32 sheets)

Sounds good but isn't that twice the price you can buy DynaMat Extreme for by shopping around? Here's 9 -18" x 32" sheets for $120 shipped or am I reading your post wrong?

http://www.amazon.com/Dynamat-10455-Xtreme-Bulk-Sheets/dp/B00020CB2S/ref=pd_sim_auto_img_2/002-1282785-6361662?ie=UTF8&qid=1196828110&sr=1-2

yeah - money isn't really the problem - time is - i needed the stuff tomorrow - i have to prep the denali for a cross country run on tuesday - i went with a known vendor that i was sure could deliver

here's the deal - i hate online shopping - i just don't have the time to do that kind of searching, and on stuff like this, the savings to be had is less than the cost of my time to do it - i've also had problems with amazon and ebay vendors before, and i don't have time for a glitch on this one

thanks for the lead though, and when i get back, i'll do some homework on it further - that price certainly makes it a no brainer, and i'll probably buy more for the doors and stuff

One other option. And it does involve Lowes or Home Deep$it. In the roofing section, they have some rolls of pliable rubber sheeting, with the density of tar, that has peel off adhesive backing. Fraction of the cost of Dynamat and almost as effective. Very popular in a Mercedes Benz forum I frequent. Side by side to dynamat it looks and feels almost exactly the same.

perhaps, but it would be nothing like dynamat extreme - night and day difference in the products