Alternative material for damping

[amit_sound]

Hi fellows,

What is the material (eg. Dynamat) used for damping, made of? Do we have any other cheaper alternative material used in damping?

I know this may sound stupid, but does material like foam etc.. do the same kind of work?

Thanks

[rareone]

I had inquired for Damping of dynamat for Front Door Panels of my Santro it was costing me Rs.1200/-

I am planing 2 go in for it

Let me also know if there is any alternate material for Damping before i go in for dynamat

Thanx...

[Bass&Trouble]

Originally Posted by amit_sound

Hi fellows,

What is the material (eg. Dynamat) used for damping, made of? Do we have any other cheaper alternative material used in damping?

I know this may sound stupid, but does material like foam etc.. do the same kind of work?

Thanks

By damping, I am assuming damping lower frequencies, not highs. Foam would do well for HF, but does practically nothing other than partly breaking up low frequencies. It cannot absorb bass. So that isn't damping.

Damping materials are made of a wide variety of constituents. Most are made of asphalt or butyl compounds (or a combination of both i.e. butyls substrate using asphalt fillers), and other polymers. The idea is to get a viscous material, which although essentially solid, mimicks the effect of fluid damping.

Asphalt based mats are usually cheaper than those with higher butyl content. But they are still more expensive than materials like foam. There are many damping brands that work well and cost about 75% lesser than Dynamat Extreme, but none are available in India in that price range. It is cheaper to us two layers of these mats to obtain desired results than spening on Dynamat.

In my opinion, Wurth is the cheapest damping material per square foot available in India, and it's reasonably effective.

[amit_sound]

Thanks B&T, your post is very informative!!

[gunbir]

Originally Posted by Bass&Trouble

In my opinion, Wurth is the cheapest damping material per square foot available in India, and it's reasonably effective.

Last time I checked, our FonoMat worked out to be the cheapest commercially available branded product, retailing for Rs 220 per 10"x10" mat. In a comparison with Dynamat Original, we found Fonomat to be more effective, easier to apply and to have far better adhesive. Out of the Dynamat range, I can really only recommend Dynamat Extreme. But it is a bit expensive though.

Back to the original question, regarding alternate materials, a good place to look for such materials are hardware stores that sell waterproofing supplies. Though mostly not as effective as application specific damping products, you can find some great alternate materials that are cheap. This especially makes sense if you plan to do extensive damping within a small budget.

[rareone]

Its going way over my head...

In short i would like you guyz to suggest a good place in MUmbai who is well know for Damping...

ALso at a very reasonable budget.

Hey Amit_Sound you also from Navi Mumbai, why dont we meet and plan to go together for Damping our cars...

Thanx...

[rsjaurr]

Even i had no idea before i actually got to see dyn.extreme.Infact it spoilt many shirts which my FIL brought along with dyn.extreme.

Rareone,basically its a sticky black material [looks like think coal tar] put in-between two sheets,one is glossy white which will be on outer side when install and other is just thin paper which u have to remove before installing.this link may help u somewhat...
http://www.team-bhp.com/forum/market...ynamat+extreme [post no.6]

I agree with gunbir that d.extreme is excellent in quality and worht every penny.I bought 4 sheets but could use only two for 4 doors and its doing the job very-very well indeed.

[amit_sound]

Get me one more thing clear, is damping use to absorb or repell low freqiences?

If it absorbs, then dosent it reduce the SPL?

If it does reduce the SPL, then is it improving SQL?

Thats a chain of questions gurus need to explain!!

[theEnd]

I'm no guru but I'll try applying some of my engineering knowledge here.

Damping is the absorption of movement. Dynamat etc dont really absorb sound, they stop vibrations from being transmitted from the speaker to other solid material (such as your car door and panel).

Ideally, for good sound only the speaker cone should vibrate, thus vibrating the air and producing sound. When the door also vibrates sound gets worse (cuz the entire door is acting like a speaker, and doors are not designed to be speakers). Also, the vibration leads to rattles (not good for sound) and eventually little things start falling off or wearing away.

So it definitely improves SQ. With regards to SPL, if less energy is wasted in vibrating various parts of your car, then more energy goes into vibrating the air (i.e. creating sound), so yes, there will actually be more loudness as well (but probably not too much).

[gunbir]

Originally Posted by amit_sound

Get me one more thing clear, is damping use to absorb or repell low freqiences?

If it absorbs, then dosent it reduce the SPL?

If it does reduce the SPL, then is it improving SQL?

Thats a chain of questions gurus need to explain!!

Amit,

try holding a single A4 sized sheet of paper 1 foot away from your subs. You will feel the vibrations in the paper. Hell it may even move with the bass. Now try the same with a bunch of A4 sheets. You will find they dont vibrate as much. Why? cuz due to the weight, density increase the resonant frequency of the combined sheets of paper changed.

Most damping materials do the same. Stuff like Dynamat, FonoMat etc are butyl+asphalt mixed masala sandwiched between cloth or aluminium sheet (based on model) for easy application. When you apply a layer of this onto a plastic door panel, you will find the weight of your door increases too. Hence less vibrations and irrirating noises.

No, it doesnt reduce SPL. as more or less the same SPL is being produced. Just that earlier the light plastic panels were coupling with the bass and producing sound effects of their own and now they arent.

[gunbir]

Originally Posted by theEnd

I'm no guru but I'll try applying some of my engineering knowledge here.

Damping is the absorption of movement. Dynamat etc dont really absorb sound, they stop vibrations from being transmitted from the speaker to other solid material (such as your car door and panel).

Ideally, for good sound only the speaker cone should vibrate, thus vibrating the air and producing sound. When the door also vibrates sound gets worse (cuz the entire door is acting like a speaker, and doors are not designed to be speakers). Also, the vibration leads to rattles (not good for sound) and eventually little things start falling off or wearing away.

So it definitely improves SQ. With regards to SPL, if less energy is wasted in vibrating various parts of your car, then more energy goes into vibrating the air (i.e. creating sound), so yes, there will actually be more loudness as well (but probably not too much).

Bravo... good answer...

[kURETI]

uuummmm ma - this really explains the need for dampaning sheets - great

[rareone]

Hi,

That was very well explained... Thanx

Now i am totally conviced for Damping my Santro Zip Plus.

I would like to know how much would it cost to me for Damping the Rear Hatch Boot and the Front Door Panels.

And which all areas will be covered with the materials for a perfect ratling solution...

[amit_sound]

Hi gunbir and theEnd, your posts were outstanding. I am clear with my doubts.

Thanks

[Bass&Trouble]

Originally Posted by amit_sound

Get me one more thing clear, is damping use to absorb or repell low freqiences?

If it absorbs, then dosent it reduce the SPL?

If it does reduce the SPL, then is it improving SQL?

Thats a chain of questions gurus need to explain!!

"If it absorbs or repels" is a question with reference to the sound wave. However, the main aim of damping materials is not exactly damping the sound wave to a very great extent. In fact, it is almost helpless with high-energy low frequency. The damping material has the greatest effect in damping the vibrating motion of the part it is applied to when subjected to a sound wave. So you applied it to a metal door, it will display reduced vibration magnitude although the acoustic pressure applied on it is nearly the same.

Simply defined, damping is the effect of a medium or device to inhibit vibrations. Air damps sound waves, for that matter.. and water could do it better. Stuff like Dynamat, Wurth damp metal etc.

Whether or not SPL is affected is a matter of where the damping is applied.

If the roof or floor is damped in an SPL system, the recorded SPL could be higher. If it's behind the speaker in your door (isolated from the cabin), it wont make any difference.

If you reduce vibration of body parts that are audible, your SQ improves. If there are materials like foam that are soaking up high-frequencies, your SQ deteriorates. So there's no one rule for that, but the conclusion could be that damping the body parts to minimize the effect of low frequency sound waves on them, is always a good idea.