Dampening Foam

[FishingFiend]

Been contemplating ordering the dampening foam from second skin, rattletrap.

http://www.secondskinaudio.com/cgi-bin/index.cgi?pg=4&p=ps

I wasn't convinced it would have any noticeable difference, so I held off. I was at the hobby store and noticed they had dampening foam for the train track guys. It looked right and it was cheap! Picked up 4 sheets for $3 each and got to working on my doors. Keep in mind they are already heavily dampened!

I'm impressed! The difference is obvious! For those who have been holding off, DO IT! Hit your local hobby store and grab a couple of test sheets. IMO Worth the effort. You can use a combination of spray adhesive and velcro for the installation. Less than an hour and real world bennefits.

[sgt]

So cheap hobby shop sound deadening = as good as expensive car audio stuff

[itsme]

where did you put it?

[FishingFiend]

I haven't tried the expensive stuff, but I got more than what I paid for. If the car audio specific material is that much better, it may be worth the money.

As for installation, cut it into pieces sized to cover empty spots and places where the metal and plastic meet. I applied it to both the door panel and the door. Use it to cover holes and gaps. Make sure to cover your door switches on the door panel. I used some velco so I could remove it when working on the car.

I'll be back in there this weekend, I'll snap some pics.

[fweasel]

I'm in for some pics.

[Deer Killer]

Been contemplating ordering the dampening foam from second skin, rattletrap.

http://www.secondskinaudio.com/cgi-bin/index.cgi?pg=4&p=ps

I wasn't convinced it would have any noticeable difference, so I held off. I was at the hobby store and noticed they had dampening foam for the train track guys. It looked right and it was cheap! Picked up 4 sheets for $3 each and got to working on my doors. Keep in mind they are already heavily dampened!

I'm impressed! The difference is obvious! For those who have been holding off, DO IT! Hit your local hobby store and grab a couple of test sheets. IMO Worth the effort. You can use a combination of spray adhesive and velcro for the installation. Less than an hour and real world bennefits.How thick and how much sq ft?

[GTTuner]

:munch: Need pics!:icon_bigg

[sgt]

What was the name of the stuff you got?

[legz]

:munch:

[FishingFiend]

Got inspired to lay some fiberglass over the weekend for a sub-box. Never made it back into my doors. I will take photos sometime later this week.

After a week with this upgrade, I'm still convinced that the foam has made a noticeable difference. My mids are really acting more like 6.5 subs!

No pics, but some more info.

www.woodlandscenics.com (http://www.woodlandscenics.com)

The brand is Woodland Scenics and it's train track bedding material. It's a dampening material, but very simplified.

It's less than a 1/4 inch think. It's actually more like 3/16.
Retail was $3.50 but I got it onsale for $3 during xmas.
Standard size: 12"x24"

This equates to $1.75 per sqft. While the Second Skin Rattletrap is $4.13 per sqft plus shipping. Rattletrap also is .375" vs. .1875 for the cheaper stuff.

With 2 layers of the Scenic stuff, I can match the thickness at $3.50 per sqft vs the $4.13 plus shipping.

In conclusion, 2 layers of the train track stuff is still a better deal and I can match the thickness. Now the quality of the foam itself, I make no claims too. IMO it works great!

[sgt]

I was thinking about trying edead teklite. Its .25" thick and seems worth trying at 2$/ft

[PGT]

I used to use the spray-on Rockford 'NoiseKiller' stuff years ago. Never felt it worked as well as Dynamat Xtreme or B-Quiet Ultimate for the money. Any of these solutions work on the same principle - adding mass to a panel lowers it's resonant frequency, so it comes down to the actual weight of the material, the cost and ease of application. There's no black magic here, despite the marketing.

[sgt]

We are talking about higher frequency dampeners and not the dynamat/butyl st uff which adds mass.

[PGT]

and how does a 'higher frequency dampener' work differently? to cut down on reflections? So, you spray your whole interior? :lol:

[praedet]

I used RAAMmat BXT (Equiv. or better than Dynamat Xtreme) with Ensolite (http://www.raamaudio.com/cgi-bin/index.cgi?p=pr) for noise attenuation. It is very obvious where the ensolite is, and where it isn't. The Dynamat and other brands are made to get rid of vibrations, the different foams lowers volume...

Ted

[PGT]

what do you mean by 'lowers volume'? volume = loudness or volume = occupied space?

[praedet]

Loudness, say of an exhaust or road noise...

[mccorry]

In for pics!

[Deer Killer]

and how does a 'higher frequency dampener' work differently? to cut down on reflections? So, you spray your whole interior? :lol:

STC vs NRC
The damping at which people use it gets very little in return.. Need sound absorbers as well as panel damping. Absorbers are generally more effective at mid to high-range where dampeners are most effective at low frequencies and resonance. I haven't heard my doors resonating at all, It would probably be most effective to skip the dynamat and spend the $ on some acoustic foam with a lead or viscoelastic barrier. It will dampen resonance if it contacts the door metal anyway.

[PGT]

ok, so butyl rubber on the door skins and frame and something like ensolite on the door panel itself? sorry, I've been out of this as a hobby for almost a decade now, after doing IASCA, etc in the 90's.

[sgt]

The idea is that the butyl rubber takes care of things below 150-200Hz and the foam helps with everything above. So the two work in combination to eliminate sounds across the entire spectrum.

[PGT]

but, butyl rubber isn't limited to 150-200hz. Why else would B&W use it to mount their kevlar midrange driver in a $15k home speaker?

[LittleBlueGT]

I'm with you here PGT. The two products do not IMO do two different things. They just help to absorb frequencies, some better at some frequencies then others.

[Deer Killer]

but, butyl rubber isn't limited to 150-200hz. Why else would B&W use it to mount their kevlar midrange driver in a $15k home speaker?Once you get into that price range you might as well be paying for fairy dust.

The effectiveness falls off with frequency, and it starts reflecting and transmitting above a certain level. With such a material hard-fixed to a sound producing surface it's least effective in blocking sound. It should be decoupled with foam on both sides. Notice this already "sounds" nothing like a crapload of dynamat over everything..

At short wavelengths you want a material to absorb the sound. Without using a spectrum analyzer I'm going to guess that most road noise transmitted through doors is above 200Hz. Therefore the most effective method use some sort of acoustic foam or fabric. If you take apart the car you see this kind of stuff all under the panels in strategic areas.. You just want more.

Also if you've ever been in front of sound-absorbing panels in a studio they're interesting, they just suck in whatever noise is in front of them, and plays tricks on your mind. That's what you want.

[FishingFiend]

I'm with the blocking higher frequency's concept. I don't believe it's meant to dampen metal vibrations?

Here's my theory.

Adding the foam accomplished a couple of things.

1. Better seal over open spots in the door. I basically covered all the holes I could with dynamat and then foam. I only did this in patches for a test. (I'll get photo's soon.)

2. Better way to seal wire/connector openings. Place one layer under the wire and 1 over the wire.

3. Covering the rocker switches. Reduced vibration here so far. I'm going back in for 1 more layer.

4. Reduced air space between the door and panel. MUCH LESS rattling from the doors now.

A combination of these positives has my mids hitting solid. IMO still worth the effort.

The acoustic properties of the other foams has me curious now. I'm going to have order some to be sure. I believe any foam can better seal the doors, hence improving the sound of any speaker setup. If you have good power running into the doors, I'm would consider this step mandatory. For $15 and an hour of your time, it's almost no harm no foul...

I'm now helping some friends retrofit their installs. That's how convinced I am. :)

[Deer Killer]

Well if you have foam squeezed between the door panel and the door metal, it's for sure going to be damped.... enough stick-on damping on the door panels for any problem spots, then a solid sheet of foam and mass-loaded barrier combination covering the door is sure to give you better performance than a few hundred sq feet of dynamat..

If you want to know how people who really design sound proofing do it (not just try to sell an overhyped overexpensive product) just look at how subaru has done it.. Thick rubber attached to foam around the floors and shifter boot. some sort of hi-density fiber based padding around noisy spots behind the dashboard and doors.. etc.. actually the shifter boot is an easy to get to example of doing it properly.

[Deer Killer]

this is what you _really_ want: http://www.b-quiet.com/lcomp.html

[FishingFiend]

"Jute and the open celled foams you can buy in a craft shop absorb moisture, leading to mildew and nasty odors."

You get what you pay for... How is the ensolite vs. rattletrap? The bquite one looks like the way to go, but it's pricey.

[mattias]

what do you guys think of this...

http://www.biltema.se/Archive/Product_images/36/Huge/36-9220_h.jpg

(if you can't tell from the picture it's two layers of foam with some high density stuff in between, total thickness 30mm)

That's what I'm planning on using in my doors when I get around changing the crappy stock speakers to something better.

/Mattias

[NickB34]

Being over an inch thick, that stuff may be a little difficult to work with. If you do go with it, make sure you post up some pics, prices, etc.

[mattias]

Yes, I also thought it was a little bit thick. I think I will try to use it where ever I can in the doors and complement with some ordinary foam where the mat is too thick.

I promise I will take lots of pictures during my whole install, which will hopefully begin soon, and post them here.

Regarding price; the price is 219 SEK (that’s roughly 30$) for 0.5 sqm, you can do the math to sq ft :icon_wink I think it will be hard for you guys to get hold of the exact same thing. I will buy it from Biltema (http://www.biltema.se/products/product.asp?iSecId=1341&iItemId=93058), that’s sort of a low budget car accessory shop here in Sweden. The stuff seems to be made for marine applications (sound proofing boats) originally so it should not (at least in my way of thinking) absorb and retain moisture very easily.

/Mattias

[happybrandon]

I'm in the process of using edead v4 (http://www.edesignaudio.com/edv2/product_info.php?cPath=21&products_id=55) on my doors right now. I have allready covered the doors with at least one layer of rammat dampening and this weekend I'm going back in and filling in all the problem areas with this as well....I'll post some pics and comments when I'm done, but it is basically the same idea - mass loader + noise reduction.