For those that have done sound deadening.

[jeepocabra]

I am about to get a shipment of new speakers for my 91. While I am in the doors I figure it would be a good time to add sound deading, probably damplifier from second skin, to the doors.

From the searching that I have done it seems the consensis is to put the material on the outermost layer of steel.

My main question is if putting sound deadning material only on the doors and the rear fenders is worth the investement? Will I notice a significant reduction in noise or is it marginal at best?

 

[Ebag333]

Yes. Cover as much as you can.

I did something a little different on the truck. What I did was take Spectrum and coat not only the outside skin, but the inner skin (facing outwards). So the cardboard portion of the doors (or what looks cardbordish), the back of the plastic panels, etc.

I was concerned about the Spectrum sticking, but didn't need to be. It stuck great. Not only did it make a nice different with the small vibrations you can get from panels rattling, it made them much stiffer and heavier. The weight difference was noticeable.

Using just a gallon of Spectum made a significant different sound wise, I'm always jealous when I drive the truck as it's a noticeable difference.


Oh, and don't forget to do the tailgate while you're at it. I just coated under the carpet, and again on the backside of the carpet.

 

[jeepocabra]

Yes. Cover as much as you can.

I did something a little different on the truck. What I did was take Spectrum and coat not only the outside skin, but the inner skin (facing outwards). So the cardboard portion of the doors (or what looks cardbordish), the back of the plastic panels, etc.

I was concerned about the Spectrum sticking, but didn't need to be. It stuck great. Not only did it make a nice different with the small vibrations you can get from panels rattling, it made them much stiffer and heavier. The weight difference was noticeable.

Using just a gallon of Spectum made a significant different sound wise, I'm always jealous when I drive the truck as it's a noticeable difference.


Oh, and don't forget to do the tailgate while you're at it. I just coated under the carpet, and again on the backside of the carpet.

What reason did you go with the spectrum? easier to put on? Better dampning?

 

[Ebag333]

You can cover more area with the spectrum, as you're only supposed to put it on about 3 mm thick (about 3 credit cards thick).

It is my intent to go back and do Damplifier over it. By using both you get a very nice effect that you won't get using just one or the other.

 

[bugsnbikes]

The largest unsupported areas (act like a drum) and produce more noise transfer.

You can tap panels with your finger pretty hard and compare different spots. You will see pretty quickly that areas nearer to supports/stiffer body parts sound a bit more dead-(not as loud) as areas like the outer door panels which are predominantly drum-like spans.

The idea with the damplifier type material is to tie those spans to the firmer spots. Adding mass wont stop the drum like effect---but it will lower the tone *ie -high pitch wheel noise or tranny gear noise will effectly go to a lower tone*.

For the doors-- you really need to do as much of the outer shell as possibly by reaching inside the holes behind the doorliner.

 

[bmac1996acc]

I've never used (or heard of) Second Skin. When I used to work as a car audio installer, we used Dynamat which is one of (if not the) original companies to make aftermarket sound damping for cars. It actually makes a huge difference. I've used the sprays and the mat with similar results.

 

[Ebag333]

The largest unsupported areas (act like a drum) and produce more noise transfer.

Yup. I noticed the biggest difference from doing the rear quarter panels. They are huge stretches of skin.

Lexus included two fairly small pieces of sound dampening there already to try and help quiet them down, dunno if the LC's have that.

 

[KurtKuhn]

I used Dynamat to effectively create a sound box out of the door. I covered this part of the door per the guidance from Crutchfield.

The Polk speakers that I used sound great with this set up; but, I cannot say that road noise was significantly reduced.

-KK

 

[jeepocabra]

Any one have any more opinions? Is 30 square feet enough? Or 40?

 

[mkfour]

I haven't done mine, but from I hear, you're going to need at least 100 sqft.

 

[lockd80]

i went the trailer park sound deadener , cost half as much and if you prep with MEK takes a heat gun to get off. three mill thick
and is a good heat sheild also.

 

[spdwaver]

i went the trailer park sound deadener , cost half as much and if you prep with MEK takes a heat gun to get off. three mill thick
and is a good heat sheild also.

Do you have any issues with odor?

 

[Ebag333]

Reasons to use the roofing products:

• Cheap.

Reasons not to use the roofing products:

• High quality products are far more effecting (Dynamat and SecondSkin is probably at least twice as effective), meaning your cost savings is mostly eliminated.
• Lower quality products have a higher chance of failure.
• Asphalt based products are not designed for longevity. This is why houses are reroofed periodically. Roofs also see more moderate temps than the inside of a vehicle.
• Asphalt based products can smell. I've been in several vehicles where the person who did the install swore that it didn't smell...first time I sat in it I could tell right away. They were just used to it, just like someone who smokes inside their car.

But all those reasons are nothing compared to the biggest one:

What Are Asphalt Fumes?
When asphalt is heated, a small portion of it is released as a
vapor. As these vapors cool in the air, some of them condense
into a cloud of tiny droplets called “fume”. Not every compound
that is part of the asphalt becomes part of the fume that is
created when asphalt is heated. Quite the opposite – only the
chemicals that are more volatile (i.e., are more readily turned into
vapors) become part of the fume. It has been estimated that only
about 0.0001 % (one-ten thousandths of one percent) of the
base asphalt evolves into fume under normal operating conditions.

(Emphasis mine.)

When you install Asphalt based roofing products in a vehicle, it is no longer under normal operating conditions.

A Harvard study showed that temps could reach over 150* with an ambient temp of only 100*. Another study showed that temps can reach nearly 170*, I've heard reports of people reaching around 200*.

Roofs are not exposed to those temps. They are only going to be slightly hotter than ambient, and the cool house below will act as a giant heatsink. You are exposing your asphalt sound dampening to nearly twice the heat it was designed for.

The more heat, the more asphalt vapor in the air. The more vapor, the more you inhale.

OSHA reports the following possible effects of Asphalt fumes:

Health effects from exposure to asphalt fumes include headache, skin rash, sensitization, fatigue, reduced appetite, throat and eye irritation, cough, and skin cancer.

So not only are you subjecting the asphalt to extreme heat (which can not only cause it to fail but will cause more fumes to be in the air), but you're doing so in an enclosed and essentially air tight space (at least when the vehicle isn't running or you have recirc on).



There's no good reason to use a asphalt based product as a sound dampener. It won't work as well, you'll need more of it to achieve the same effect (meaning your cost savings are negligible at best), and it might kill you.

And even if you don't care about the effects on you, think about the effects on others. How about those of us with kids or friends of have kids? How about a newborn?

 

[spdwaver]

Ebag333: Could you elaborate, please?








J/K

Thanks for the info. on that. I figured that anything with an asphalt base would not safe to have inside a vehicle, and cheap is not always worth it.

 

[NKP Garage]

I've personally always put this stuff on the doorskins, floors, and wheel wells: Cascade VB-1S PRO Quiet Kote Damping Spray Cascade VB-1S PRO Quiet Kote Damping Spray [] - $15.90 : EMSPowered, High Quality, Great Service, Low Prices

And then matting on the inside of the doors.

 

[spdwaver]

To add to Ebag333's information, here is a link to the MSDS PDF from Cofair's website on Quick Roof:

http://www.cofair.com/pdf/msds/QRMat Safe Data.pdf

 

[Marc311]

IIRC, I think I bought about 140 sq ft of Damplifier for my FJ60 and had about 20 sq ft or so left over. That was covering doors, tailgate and floors. By no means 100% - probably about 75% coverage. Although I think more is better, I also think it begins to be diminishing returns. Covering the final 25% probably only would have improved the sound deadening 2% (rough numbers pulled from my ass for demonstrative purposes).

30 sq ft seems a bit low to do the doors and fenders. But even with that you will notice a large difference (if nothing else, a satisfying thud when you close the doors).

I also agree with bugsnbikes "tap" method. It really makes it clear where, and where not, to put the deadener.

 

[Ebag333]

To add to Ebag333's information, here is a link to the MSDS PDF from Cofair's website on Quick Roof:

http://www.cofair.com/pdf/msds/QRMat Safe Data.pdf

One point on that PDF jumped out at me:

Melting Point: >200 degrees Fahrenheit

Since vehicles can easily see 150* or higher on a 100* ambient day, how close do you think they'll get to 200* on a 110*+ day?

No wonder so many of the installs using the asphalt sheeting fail. It doesn't even need to melt, just get soft, then you have a huge, nasty, sticky mess in your truck.

 

[lockd80]

Do you have any issues with odor?

nope.

 

[lockd80]

One point on that PDF jumped out at me:



Since vehicles can easily see 150* or higher on a 100* ambient day, how close do you think they'll get to 200* on a 110*+ day?

No wonder so many of the installs using the asphalt sheeting fail. It doesn't even need to melt, just get soft, then you have a huge, nasty, sticky mess in your truck.

Is this from personal experience? My cruiser has been in eastern washington desert every summer since I put this stuff in and neither has it fallen off nor has it turned into a sticky mess, looks just as it did when I installed it and when I needed to do some body work recently carfull use of a heat gun was all it took to remove it.