[Sam Kapasi]

Originally Posted by navin

Hey this is good. For 5K you can get 4 rolls and do front doors and the trunk of most cars. Is there a Mumbai source! I need 12 x 1 meter rolls for a few friends cars.

I've ordered 4 rolls. Can order more. In fact I am sure Anil will send to you. His number is public knowledge as hot tracks is the most famous Alloy Wheel Retail store in India.

[gunbir]

Originally Posted by hydrashok

Nope. It is open-cell foam. It will retain moisture if it gets wet. Not a very good thing. But this is a good and cheap alternative if used in places that will not get wet at all. Using them in the doors would be pretty dangerous in the long run (rusting issues).

Spot on Hydra.

And though I recommend you use proper damping materials, there is no doubt alternative materials can work well too. For DIYers there is one type of closed cell foam you can buy anywhere. Thats the foam used in bed mattresses. Looks like this...



Please do check whether its open cell or closed cell foam before you use it though. Do a simple test, put some drops of water on it, if it doesnt absorb the water, its closed cell foam.

[mobike008]

This is great piece of information. How would you Gunbir and other audio gurus rate the effectiveness of these foam dampeners against regular dampening products? What could be the cost of these regular foam in the approximate sense?

[Sam Kapasi]

No product can damp as well as a butyl based damping product, either sheet or spray. No matter what you use, the perfect damping that you can get from a engineered damping product is always better than cheaper alternatives.
In short, there's nothing quite as good for damping as Wurth, Fonomat, Dynamat, American Acoustics and the ilk.

[theEnd]

Hey, if anyone is ordering further quantities of this American Acoustics damping in Mumbai can you let me know. My front doors have started their own orchestra and need a lot of damping. I'd be happy to come and pay you before ordering and pick it up when it comes.

[Sam Kapasi]

OK let's do this.

Let me speak to Anil and see what he can do about sending about a dozen rolls here. Since Rtech and Navin also want some.

[gunbir]

Originally Posted by mobike008

This is great piece of information. How would you Gunbir and other audio gurus rate the effectiveness of these foam dampeners against regular dampening products? What could be the cost of these regular foam in the approximate sense?

Originally Posted by Sam Kapasi

No product can damp as well as a butyl based damping product, either sheet or spray. No matter what you use, the perfect damping that you can get from a engineered damping product is always better than cheaper alternatives. In short, there's nothing quite as good for damping as Wurth, Fonomat, Dynamat, American Acoustics and the ilk.

What Sam said ^^^. But let me explain further.

Damping in the car audio context essentially means increasing the weight of plastic and metal panels that have a tendency to resonate at certain frequencies. By increasing their weight you shift their resonant freq thereby reducing vibrations and resulting noise. To increase the weight of these panels, materials like Dynamat etc are used as they are adhesive, flexible and designed for this application.

When you use alternate materials such as foam, rubber etc. and stuff it in between panels, you essentially transfer some of the energy from the vibrating panels into the foam material (thats in direct contact with the panel), thereby reducing vibration. But the effectiveness of this is in my opinion lesser than that of the Dynamat variety. So while its a cheap fix, its not the best fix.

[mithun]

Originally Posted by Sam Kapasi

Hot Tracks, Bangalore has lots of rolls of American Acoustics damping. Anil Padiwal is very kindly sending me 4X1 metre rolls of the stuff for my verna. I will surely put up pictures and a review.

By the way, guys, since this is a thread on VFM damping, I would tell you that it was an impressive product. I was also told that a large 1 metre roll of this is about Rs. 1300-1400 in retail.

Sam, Thanks for your valuable info.

So, for a hatch like Swift, how many metres of American Acoustics damping is required ?

[Bass&Trouble]

Sam, I've never heard of American Acoustics. It could be ignorance on my part. But I'm sure you'll evaluate the product once you have it.

In Mumbai, I have seen some Chinese products in polythene packing with American brand names masquerading as 'damping'. On closer observation, they turned out to be nothing but EVA.

Gunbir, foam used for mattresses is usually open celled foam. Open celled foam can take the maximum amount of stretching without rupturing, hence the use. Strictly not recommended for damping use, and like you pointed out, foam hardly adds any mass or rigidity to any panels.

[Sam Kapasi]

Originally Posted by Bass&Trouble

Sam, I've never heard of American Acoustics. It could be ignorance on my part. But I'm sure you'll evaluate the product once you have it.

Neither had I! But I did see it on my various travels. I did check it out, it was a lot of weight and decent packing. Looked like quality stuff to me.
And Navin has heard of it. So that sorta settles it. So let us drink, smoke in the upward direction, be merry and ignorant together.

[navin]

Originally Posted by Sam Kapasi

No product can damp as well as a butyl based damping product,.

Butyl is relatively easy to apply and while it is not as cheap as foam or asphalt baed stuff it can be bettered.

Somewere (about 2 years ago) I has posted about the "correct" way to make speaker cabinets. I remember it got Sam (and Vivek Phadnis) all excited. I think it was one of the few posts that led to the creation of "the LONG thread" on the ICE forum.

The same techniques can be used to damp an exisiting surface.
Materials that can be used
a) Resin Bonded fiberglass mat
b) 1.5mm thick lead sheets
c) Epoxy glue
d) UV grade Butyl rubber sheet

I am not going to detail the procdess here as it is long and I have realised that my posts (see my earlire posts) often switch people off. I think these posts were the reason why the ICE forum did not grow larger. However if there is a demand for this it can be detailed on as a Sticky in a seperate thread. Sam, wipe that grin from your face - if they want IT they will get IT

For the record in a car I would NOT recommend open cell or closed cell foam and wold recommend asphalt based products only partially.

[low_bass_makker]

Hmmm Navin Ji in full mood...and yes we want to learn thats why we are at T-bhp......

[navin]

Originally Posted by low_bass_makker

Hmmm Navin Ji in full mood...and yes we want to learn thats why we are at T-bhp......

i just dug up a paper presented about 10 years ago on basic damping from my bookmarks.
Acoustical Society of America - Decibel by Decibel, Reducing the Din to a Very Dull Roar

BTW the only Foam one could use in the car is the Marine grande PVC foam. It is UV proof and wont deteriorate.

[navin]

Originally Posted by Sam Kapasi

And Navin has heard of it. So that sorta settles it. So let us drink, smoke in the upward direction, be merry and ignorant together.

not all products made is China are bad. AA is made in China. So what. it is VFM and I am a Cheapskate just ask anyone.

[Sam Kapasi]

So here's the roll when it arrived in me office. I recd 3 rolls today. So much for American Acoustics lol, it turned out to be american dynamic!! hehehe. I'm very bad with names.


Took it outside and opened it up. Looks alright. Feels like any other damping material. It's heavy and a bit soft. Good.



It's a big sheet, but I want to do some serious damping. Have decided to use all 3 sheets on front doors. A double layer pf damping, on the inner wall and outer wall.


Warming it up a bit, made it more supple and will cause the glue to catch on tighter and harder. The installer shows us that there's more than one use for a professional hair dryer lol. (PS he should have had an industrial hot air gun)

Finished the inside, now for the outside. For a car like the verna, 3 sheets in minimum for the front 2 doors. It's a bit kanjoos actually. You need about 3.5 sheets.
For a car like a skoda, you would definitely need 4 sheets. But for small and mid sized cars, 3 sheets for the front doors.



It's still not complete, the entire outer panel will be covered too.

Now to phone Anil and ask him to send 3 more rolls. I have to do the boot and the rear parcel shelf.