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Old 08-02-04, 01:14 PM
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kaosmoon
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Default Sound Deadening Overview.

We recently did a sound deadening group buy here and I got a lot of questions / e-mails regarding sound deadening and stuff so I figured this couldn't hurt.

http://www.icixsound.com/vb/article.php?a=1

That's a link to a pretty comprehensive sound deadening overview about application and types. How much etc etc. It's not perfect nor is it spell checked I don't think but all in all it's a decent resource for reading if you guys are interested in some of that stuff.

Just figured it might be a decent link of interest.
Old 08-14-04, 02:30 PM
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TwentyTen
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This is a very informative article but the author is partial to Liquid sound deadeners and it was written prior to Dynamat XTREME. My entire trunk, rear baffle, front and rear doors are covered in Dynamat XTREME and NEVER have I smelled asphault. Not even when applying. It's more like EXTREMELY THICK and STICKY rubber or rubber cement.
When you do this your making a permanent change to your car and using tons of sound deadening. Your floor will heat up, as will your roof which will cuase in this case a direct absorbant path for that mat. In other words. When it gets hot, you've got so much asphualt in your car it's going to smell like a highway no matter what you do inside it. The liquid option doesn't change smell with temperature & doesn't develop one.
Your trunk lid is held up by support bars, torsion bars, hydrualic bars. To really DEADEN the lid using mat or liquid your going to need to use a obscene amount of either. We're talking 40-50lbs of mass added to your trunk lid. It's hard on your car, not only on it's shape, but on the support beams. That and do you REALLY want to have to open a 40lb trunk lid everytime you get grocerys? I hope not.
My trunk lid is a little heavier but NOT 40lbs heavier. I bought the bulk pack and I thingk the whole package was 30-40lbs.
From Dyanamt.com:
-------------------------------------
Name: Dynamat Bulk Pak
Contents: (9) 18"x 32" (9) 457mm x 812mm* pieces of Dynamat Xtreme
Application: Use on rear decks, doors, floors and the floor of your trunk to get more bass, more music, lower road noise and better sound.
Price:$249.95 US Retail
-------------------------------------

Problems I have with Dynamat XTREME are 1.) how hard is was to get into the nooks and crannies 2.) how many times I cut my fingers/knuckles when cutting throught the fine aluminum heat shield layer and 3.) It gets much quieter in the car but the Sound Pressure Levels in the car are INSANE, you could seriously hurt yourself if you're not careful.

Oh yeah - and it DRASTICALLY REDUCES THE AMOUNT OF SOUND THAT ESCAPES THE CAR. Meaning, you can't hear squat if you're not in the car.
Old 08-15-04, 04:53 PM
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kaosmoon
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Daruis,

any and every single asphualt based mat based product I've ever used, including dynamat, edead, brown bread. The list goes on and on if asphualt based, if it breaks down. It smells. That's the downfall to the main layer of it. Including our own product keep in mind.

When heated to a certain point if asphualt breaks down. It smells.

Long story short. This is not a every case instance in the entire world. Your product if asphualt based has never heated up to a point where you would smell it...

It's wonderful the dynamat has worked well for you!
Old 08-15-04, 10:20 PM
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TwentyTen
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Check Your PM.
Old 08-16-04, 02:35 AM
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mikee72
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Kaosmoon, since you're "in the biz," I'd like to offer a suggestion and voice a bit of frustration on the subject of sound deadening. When I'm in the market for a product such as damping/deadening/etc., I'd like to be able to make a quantitative assessment of it's performance. When it comes to Car Audio, it's very difficult to find anything beyond the typical "It made my car hella quiet, dude," let alone STC and TL info. While some companies offer this data, they don't give the average reader any idea of how this translates into a quieter car. Show me a before/after dB reading of a Honda Accord at 60 MPH with X amount of your product placed in specified areas. Tell me how much low frequency response was gained after installing your product in the trunk and doors. I firmly believe that the more info you give the prospective buyer, the greater the chance he'll buy your product. Just my $.02.

Last edited by mikee72; 08-16-04 at 05:43 AM.
Old 08-16-04, 07:38 AM
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kaosmoon
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One big reason for this lack of information when it comes to car audio. honestly mass is mass. Most of that information is a companies spin on it. I emphasise 'spin'. I've sold the big name deadening products and there's a solid reason why we released our own, and leave it dirt cheap. deadening is deadening.

Put it in right and take your time installing it honestly is worth more than any amount of acoustic anylasis of loss or something to that effect. I'm sure there are those who will have a different viewpoint but it's probably to support their own label. That however is MY opinion and isn't going to reflect everyones viewpoint.

My approach to deadening is very simple. It's mass. Your adding mass. Find something that doesn't fall off, break away, break down, or rather deteriote under the conditions your going to use it in. and bam. Success.

If you want that type of reading honestly your better off going with someone who took the time to market it as something rather than a product you put in, and put in right to get results. We just don't do that. If we quadruple the price of it and people continue to buy it though I'd be happy to buy all the mics and do the readings over a few beers with some friends
Old 08-16-04, 07:56 AM
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mikee72
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Fair enough then. Given that mass is the most important aspect, why don't more companies incorporate lead in their products, or incorporate a more substantial amount than they do? I once bought a product that was essentially a sheet of 3/8" lead with a thin rubber covering for a previous car ~10 years ago, but have yet to find anything similar these days. It was the most effective substance I have ever used for road noise/loud exhaust applications, but the shop I bought it from is no longer in business. I see products with 1/16" thick lead inside asphalt/foam, but nothing as think (and massive) as what I had.
Old 08-16-04, 08:11 AM
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Well I can see why 'lead' isn't used. Considering some of the health effects.

http://www.epa.gov/superfund/programs/lead/health.htm

Quite honestly concrete is going to be the top of the top as far as the 'best' deadener goes.

But companies need to walk a line between returns of product good, and downfalls. Most people just can't afford to add 500lbs to their cars and not care.

So the result is thinner (in most cases no thicker than 60mil) sheets or paint on style liquid where the user / installer can pinpoint areas where it may be a problem or need to be added.

People need to be able to deaden their vehicles without too much knowledge of the substance. Without any sort of health effects. Which is why I would guess more people don't just run to roofing materials, and that doesn't break away / has been tested proven to last.

Do you remember the brand name on that lead based product you purchased? I will be quite honest. I've never heard of it being used. But I also haven't been doing this for quite a decade.
Old 08-16-04, 09:44 AM
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mikee72
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I bought the stuff in bulk from an auto upholstery shop. I believe they cut it from a roll, but no brand name was ever mentioned. I didn't have a dB meter back then, but I'd guess that it gave a 5-6 dB reduction, just by laying it on the trunk floor. My assumption is, to get the equivalent noise reduction with asphalt mat, it would require a similar weight's worth of product which would be much thicker, since it isn't as dense. I can't imagine that lead would be a health risk if were fairly well encapsulated as the stuff I bought was.
Old 08-18-04, 08:15 AM
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Hey guys, while I agree that 'mass is mass' and that adding mass will always have an effect on the resonances, I still think that some materials are still better than others and sure wouldn't mind seeing more (better) quantitative analysis from all of the manufacturers. I'd expect some materials to be better at certain frequencies and worse at others, and I'd much rather be adding more mass of a more effective material. Main reason I say this is that since we can't use the concrete or lead you mentioned, everything else is a compromise of weight vs. attenuation vs. frequency vs. ease of application vs expense.

My .02.
Old 08-18-04, 08:35 AM
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Actually. Yes. You are correct.

Different materials have different effects on different frequencies.

Ie. Certain higher frequencies can be absorbed into a porous cloth (ie. tshirt, carpet) etc etc. This is a large reason why dashmats in iasca and usac are so dreadfully popular right now. reflections are the devil! lol.

I actually had a discussion with a gentleman at Steel Valley this year regarding tuning the vehicle without the use of electronic equalization equipment where his car was built using different materials in different locations to change the responses in certain locations or 'physically equalize' the system. Very cool indeed.

What I believe this article is addressing is the generic point of sound deadening. aka, adding weight where it's needed. Not really attenuating frequencies. But I do see your point and I do agree. When used properly or improperly for that matter different materials can and will have different effects on the vehicles sound in certain respects.

However with generic mat, liquid, foam there has to be a point where we see the difference between mass and equalization.

I do agree!
Old 08-18-04, 08:44 AM
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Interesting. That "physical equalization'" thing has to be really freakin' difficult - prob a lot of trial and error until it works out the way you'd want it to.
Old 01-17-05, 02:27 AM
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i just got a bulk pack of dynamt. any tips on where i should place the dynamat?

Originally Posted by Darius2010
This is a very informative article but the author is partial to Liquid sound deadeners and it was written prior to Dynamat XTREME. My entire trunk, rear baffle, front and rear doors are covered in Dynamat XTREME and NEVER have I smelled asphault. Not even when applying. It's more like EXTREMELY THICK and STICKY rubber or rubber cement.


My trunk lid is a little heavier but NOT 40lbs heavier. I bought the bulk pack and I thingk the whole package was 30-40lbs.
From Dyanamt.com:
-------------------------------------
Name: Dynamat Bulk Pak
Contents: (9) 18"x 32" (9) 457mm x 812mm* pieces of Dynamat Xtreme
Application: Use on rear decks, doors, floors and the floor of your trunk to get more bass, more music, lower road noise and better sound.
Price:$249.95 US Retail
-------------------------------------

Problems I have with Dynamat XTREME are 1.) how hard is was to get into the nooks and crannies 2.) how many times I cut my fingers/knuckles when cutting throught the fine aluminum heat shield layer and 3.) It gets much quieter in the car but the Sound Pressure Levels in the car are INSANE, you could seriously hurt yourself if you're not careful.

Oh yeah - and it DRASTICALLY REDUCES THE AMOUNT OF SOUND THAT ESCAPES THE CAR. Meaning, you can't hear squat if you're not in the car.
Old 01-17-05, 03:35 AM
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TwentyTen
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The four door panels, underneath the rear deck, behind and below the rear seat, sidewalls of the trunk.
Old 02-28-05, 03:55 PM
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Eric Holdaway
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One of the things that I see on a regular basis, when it comes to Damping a vehicle, is that people do not get the most out of the product they buy, because they may be using the wrong product types for the job at hand...

example.... If you want to limit the road noise, you should be using a BARRIER type of sound control material and not a visco-elastic damper like Xtreme. Barriers are typically a minerial loaded vinyl or a lead sheet with a decoupling foam, and it would go on the floor, firewall, package tray... anywhere you can get it to stay. This type of material literally stops sound from coming through it..

Visco-eleastic dampers should be used to improve the sound of the audio system... ie.. sealing doors, rear deck, roof, door skins and around the speakers.

You can get a lot better preformance out of your sound control purchases, if you get the right stufff to do the right job.


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