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Discussion Starter #1
Ok I know this topic has been covered ad nauseum as I've scoured the boards researching it. Now that I've gotten a better hold of the science behind it I'm going to tackle it from a fresh perspective. All of my new stereo components are either here are on their way so it's time to start tackling the least enjoyable part. Car is a 2006 Scion Xb which has little to no deadening in it from the start, not to mention an annoying exhaust droan while on the freeway which is where most of my driving takes place due to my commute everyday.

My previous experience in sound deadening my last 2 cars has been Peel'n'Seal and a bunch of carpet padding. Compared to nothing it worked wonders, however I know now that it could have been so much better. This time I'm taking a more detailed and thorough approach and would like some input or suggestions. Budget is a concern so I will likely do it in steps, and as much as I'd love to lay down 150sq of Damplifier Pro and LLP I don't think I could manage it. From what I've gathered on this forum is that the method of deadening is more important than just the quality of deadening products themselves. Ie; Damplifier pro with a half-assed ensolite layer on top won't be as good as a lesser vibration dampener with a quality uncoupler and barrier on top.

Which brings me to my current plan:

1. Lay down a good solid layer of Raamat in my car, doubling up in areas like front doors, firewall, trunk and quarter panels.

2. Lay down a layer of CCF for a decoupler. Since it will be compressed it doesn't make sense to me to buy a super expensive foam when the compressed thickness won't be able to absorb much anyways. Plan is to use he ensolite from Raamat since it's relatively cheap and easy to use.

3. Throw down a layer of 1lb/sq foot of MLV, possibly doubling up in key areas in the trunk to ensure blockage of the exhaust droan. Found a place locally in San Francisco that sells a 100 sq/ft roll of 1/8", 1lb/sq foot MLV that I can pickup for 140$.

4. Toying with the idea of stuffing a bunch of cotton batting behind any panels in the trunk lid, quarter panels and even the dash after all the other deadening is in. I know the batting should help absorb higher frequency sounds though would it even be worth it if the first 3 steps are done correctly?

That's the plan though I'm looking for suggestions or other input and hopefully a few q's answered.


Do I need another layer of ensolite on top of the MLV before I put the car back together or is it not worth the extra money for what improvement it may give me? Ie; since it's only meant to be a decoupler will it do any good to decouple the MLV to my carpet and plastic panels?

Other than the doors where my ID OEM's are going, is there truly any benefit to adding more layers of Raamat since I'll be using MLV as a barrier? Overall thickness is a concern when putting panels back on so what gives the most bang for the buck. Extra MLV or extra dampener?

Would it be good to use a layer of MLV on the door panels as well, or is it best to use just the ensolite since I've gotten limited thickness to work with?

One last thing. Since it's impossible to get a true un-broken barrier of MLV on the floors, how much should the sections overlap and what type of tape is good for the seams?


Sorry for the long post but I really want to do this right the first time, not waste any money or time on things that may only give me a 2% benefit and have it actually work well.

Fox and Rudeboy I'd value your input greatly.
 

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Don't think in terms of layers of vibration damper - 25% coverage at the center of flat panels is adequate. Don't bother with convoluted panels at all.

A compressed decoupling layer gets you nothing. It actually looks like thin (1/8", 1/4") decoupling layers don't do much anyway. What CCF will give you is pretty good high frequency attenuation, but in my tests it doesn't matter if the foam is between the substrate and the barrier or on top of the barrier. The idea is to 1) prevent vibration transmission into the barrier - which vibration damper should handle and MLV is pretty non-resonant and 2) present a more complicated path for transmission, but it looks like the frequencies impacted by this strategy are limited by the thickness of the decoupling layer.

1/8" foam is going to attenuate most at frequencies > 24kHz, 1/4" > 13kHz. An argument can be made that a rough surfaced foam installed on top of everything else will help with reflections but you're not likely to want to do that unless your are willing to sacrifice appearance for performance.
 

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Forgot to mention - you need to choose your adhesive or tape for vinyl carefully. As an example, none of the usual spray contact adhesives used for foam will hold vinyl. For tapes, I've had the best luck with those using an acrylic adhesive - most duct and aluminum tapes use rubber. Definitely a good idea to test first.
 

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Discussion Starter #4
Thanks for responding.

So as for the MLV, does it have to be taped down at all when on the floorboard? I was only planning on taping up the seems or where the edges are, wasn't even considering any type of adhesion to the foam or dampener itself.

Also are you saying that since I'll be using MLV as my barrier I won't need to worry as much about the vibration dampener coverage as long as I use it wisely? It seems most people use the vibration dampeners as both a dampener AND a barrier, which is why they tend to do a full coverage. Since I'll be using a dedicated MLV barrier the extra vibration dampener is then simply overkill and should only be thought of in it's primary job of adding the mass to large panels?

If that is true and I'm getting a rull 100sq/ft roll would I get better results if I used the minimum amount of dampening, then used a double layer of MLV where possible? If so would I get ANY benefit to sandwiching ensolite in between the MLV layers or would simply using 2 layers of the MLV(equating to 2lb/ft)be sufficient?

Also about the CCF.. if 1/8" won't do much good it seems that the cheap CCF carpet padding I used before wasn't such a bad idea, other than the obvious thickness problems when putting interior back in.
 

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Thanks for responding.

So as for the MLV, does it have to be taped down at all when on the floorboard? I was only planning on taping up the seems or where the edges are, wasn't even considering any type of adhesion to the foam or dampener itself.

Also are you saying that since I'll be using MLV as my barrier I won't need to worry as much about the vibration dampener coverage as long as I use it wisely? It seems most people use the vibration dampeners as both a dampener AND a barrier, which is why they tend to do a full coverage. Since I'll be using a dedicated MLV barrier the extra vibration dampener is then simply overkill and should only be thought of in it's primary job of adding the mass to large panels?

If that is true and I'm getting a rull 100sq/ft roll would I get better results if I used the minimum amount of dampening, then used a double layer of MLV where possible? If so would I get ANY benefit to sandwiching ensolite in between the MLV layers or would simply using 2 layers of the MLV(equating to 2lb/ft)be sufficient?

Also about the CCF.. if 1/8" won't do much good it seems that the cheap CCF carpet padding I used before wasn't such a bad idea, other than the obvious thickness problems when putting interior back in.
I wouldn't do anything but close the seams on horizontal surfaces either. I'm not a fan of using any more adhesive than is absolutely essential.

The strategy of using vibration damper as a barrier was a mistake - it's ineffective, costs too much and can get in the way of future maintenance. No point in doing more than 25% coverage at the centers of panels.

Each additional barrier layer will yield less improvement than the one before it. The first layer of MLV will probably get you 7-10 dB. The next, around 3, the third even less. Not saying that 3 dB isn't going to be meaningful to you. In a door, I'd expect a layer of barrier on the outer skin, one on the inner skin and maybe one inside the trim panel to give you better results because of the relatively large airspace between them.
 

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So as for the MLV, does it have to be taped down at all when on the floorboard?
It's not supposed to even be in direct contact with the floorboard, hence the use of the CCF decoupler. If you set the barrier in motion by coupling it to something that vibrates, it will fail to attenuate noise at frequencies below that point. This is why they say a barrier is only as good as it's RF (resonant frequency).

Also are you saying that since I'll be using MLV as my barrier I won't need to worry as much about the vibration dampener coverage as long as I use it wisely?
I'd say that. But a damped substrate is better than an 'alive" one. Question is: what's the RF of the substrate and would damping it be worth your while in an inheretly noisy, moving vehicle where you're surrounded by noise?

It seems most people use the vibration dampeners as both a dampener AND a barrier, which is why they tend to do a full coverage.
I'd say most use vibration dampers ineffectively as vibration dampers. There's no doubt you can get some transmission loss by damping a panel. Parts Express sells a device that can turn any flat surface into a virtual speaker by causing it to resonate. If you apply vibration damper to that surface (say a wall made from sheetrock and 2x4 studs) it won't be much of a speaker 1) and 2) you'd hear it a lot less in your house. Here you used a vibration damper as a such and it also helped reduce air borne noise (what a barrier is designed to do). Obviously, this argument can be made in lots of examples.

Since I'll be using a dedicated MLV barrier the extra vibration dampener is then simply overkill and should only be thought of in it's primary job of adding the mass to large panels?
Well any extra damper is overkill. My experience is that mass begins where vibration ends. 70% coverage on a large, flat panel should be sufficient. Couple a sub or a midbass to that panel, then you might need some mass. Your typical CLD mat at .4 lbs/sqft is not very massive. Whoever tries to tell you that vibration damping is nothing more than mass loading, put them on your ignore list and report them to the Homeland Security because they are probably a terrorist. ;)

If so would I get ANY benefit to sandwiching ensolite in between the MLV layers or would simply using 2 layers of the MLV(equating to 2lb/ft)be sufficient?
A double wall barrier is obviously more effective than a single. All else equal, Two 1/8" layers of MLV with 1/8" CCF separating them is superior to one 1/4" layer of MLV with a single 1/8" CCF decoupler. If you study the STC ratings of wall partition designs, this is what you'll see.
 

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A double wall barrier is obviously more effective than a single. All else equal, Two 1/8" layers of MLV with 1/8" CCF separating them is superior to one 1/4" layer of MLV with a single 1/8" CCF decoupler. If you study the STC ratings of wall partition designs, this is what you'll see.
Except those wall partition designs have more than 1/8" between the barrier layers. There should be some improvement going from 1/4" MLV/1/8" CCF to 1/8" MLV/1/8" CCF/1/8" MLV, but I'll bet it will be less than 1 dB in the very high frequencies only. It's an interesting question and I'll try it the next time I have the test rig set up.
 

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Each additional barrier layer will yield less improvement than the one before it. The first layer of MLV will probably get you 7-10 dB. The next, around 3, the third even less.
1 kg/m2 of anything at 75hz *should* block 0 dB.
2 kg/m2 of anything at 75hz *should* block 6 dB.
1 kg/m2 of anything at 125hz *should* block 8 dB.
2 kg/m2 of anything at 125hz *should* block 14 dB
1 kg/m2 of anything at 250hz *should* block 14 dB.
2 kg/m2 of anything at 250hz *should* block 20 dB.

Just giving an illustration because I'm bored, have clinical OCD and have already checked out all the new porn for the day.
 

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Except those wall partition designs have more than 1/8" between the barrier layers. There should be some improvement going from 1/4" MLV/1/8" CCF to 1/8" MLV/1/8" CCF/1/8" MLV, but I'll bet it will be less than 1 dB in the very high frequencies only. It's an interesting question and I'll try it the next time I have the test rig set up.
You are the MAN!

Sometimes...when I'm all alone...and it's dark and late and no one is around....I look at this....Sound Transmission Class (STC) Impact Insulation Class (IIC) - Sound Test Data for Architectural Products

It's obviously an ad for the product but it's interesting to see how the STC changes as space or materials are added/subtracted.
 

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Discussion Starter #10
Thanks for the input guys, this is what I was hoping for. I think alot of people always equate "more is better"(and in terms of mass I guess that is true..) and just throw a bunch of vibration damper in their car and hope for the best. To me it seems like your best bang for your buck is in the MLV and if I can get that 100sq/ft roll it'll be the best 139$ spent on my install.

So it sounds like just enough vibration damper to achieve it's goal, at least a single layer of MLV on my entire floorboard, quarter panels, etc.. and double up wherever I can without making it impossible to reinstall my interior. Sounds like a CCF in between is definately worth it since it's cheap and won't add too much thickness. What about the foam batting? Worthless to stuff inside panels with a lot of air space since it'll only trap high frequencies?

At any rate there is a guy selling a Dynamat extreme 2 door kit really cheap on craigslist which I think has 13sq/ft which should be enough for my front doors. I usually hate dynamat due to price being rediculous but since it's a really good deal I think it might be worth it.

In a door, I'd expect a layer of barrier on the outer skin, one on the inner skin and maybe one inside the trim panel to give you better results because of the relatively large airspace between them.
So just to be sure, you are referring to MLV as the barrier and not the damper right? Need to figure out how to bond the MLV vertically without falling off. More researching to do...
 

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Thanks for the input guys, this is what I was hoping for. I think alot of people always equate "more is better"(and in terms of mass I guess that is true..) and just throw a bunch of vibration damper in their car and hope for the best. To me it seems like your best bang for your buck is in the MLV and if I can get that 100sq/ft roll it'll be the best 139$ spent on my install.

So it sounds like just enough vibration damper to achieve it's goal, at least a single layer of MLV on my entire floorboard, quarter panels, etc.. and double up wherever I can without making it impossible to reinstall my interior. Sounds like a CCF in between is definately worth it since it's cheap and won't add too much thickness. What about the foam batting? Worthless to stuff inside panels with a lot of air space since it'll only trap high frequencies?

At any rate there is a guy selling a Dynamat extreme 2 door kit really cheap on craigslist which I think has 13sq/ft which should be enough for my front doors. I usually hate dynamat due to price being rediculous but since it's a really good deal I think it might be worth it.



So just to be sure, you are referring to MLV as the barrier and not the damper right? Need to figure out how to bond the MLV vertically without falling off. More researching to do...
Yes, MLV = barrier. There can be an advantage to stuffing voids with absorbent material since it stops the open area from acting as a transmission tunnel. I do worry about using anything that can hold moisture.
 

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One thing sort of slid by. Using a CCF layer that will compress when installed is pointless, but thee is CCF that will not compress in this application. There would be an advantage to using one of those. The specifications to look for are "compression" and "compression set".
 

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In a door, I'd expect a layer of barrier on the outer skin, one on the inner skin and maybe one inside the trim panel to give you better results because of the relatively large airspace between them.
So you are saying to put a layer of MLV on the outer skin of the door essentially in the airpsace of the midwoofer in the door? Won't that cause reflections and unwanted backwaves? Or am I missing something here?
 

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So you are saying to put a layer of MLV on the outer skin of the door essentially in the airpsace of the midwoofer in the door? Won't that cause reflections and unwanted backwaves? Or am I missing something here?
It's going to cause fewer reflections than sheet metal. It's going block noise coming in and music going out. It's definitely worth considering.
 

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It's going to cause fewer reflections than sheet metal. It's going block noise coming in and music going out. It's definitely worth considering.
So it would be a better solution on the outer skin than a dampener like raamat with ensolite on top? Sounds like the answer is yes. Or would a combo of those two be best? Sorry for the spoon feed festival.
 

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So it would be a better solution on the outer skin than a dampener like raamat with ensolite on top? Sounds like the answer is yes. Or would a combo of those two be best? Sorry for the spoon feed festival.
I think you need a vibration damper, no matter what else you do, but you don't need as much as we have been using - 25% coverage is sufficient. Using a layer of thin foam inside the door to deal with reflections and backwaves makes no sense to me at all. Every possible explanation for this practice is wavelength dependent - you don't start to get any sort of meaningful refraction or diffraction until the material thickness gets to 1/4 of the wavelength of the frequencies being targeted. At 1/8" you can only hope to influence frequencies higher than 24kHz. Is that frequency range really a problem in your doors? :) On the other hand, for 200 Hz, you'd need a material that's at least 15" thick.

This is why you should put as much effort as you can into making the speaker mounting surface a decent baffle instead worrying too much about what is going on behind it.
 

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This is why you should put as much effort as you can into making the speaker mounting surface a decent baffle instead worrying too much about what is going on behind it.
Well, as far as what I can gather to help the baffle, I've done the non-hardening clay already, with about 1 lb per door with some between the speaker itself and the 1/2" mdf baffle, then between the mdf and the inner door skin, and have also dampened the inner skin. Would the only further step be to lay down some MLV on the skin and the door card to block a little more noise? I'm leaning towards 1/4" MLV on top of ccf as the 1/8" MLV ccf sandwich sounds like it wouldn't be any more effective.

I think you need a vibration damper, no matter what else you do, but you don't need as much as we have been using - 25% coverage is sufficient. Using a layer of thin foam inside the door to deal with reflections and backwaves makes no sense to me at all. Every possible explanation for this practice is wavelength dependent - you don't start to get any sort of meaningful refraction or diffraction until the material thickness gets to 1/4 of the wavelength of the frequencies being targeted. At 1/8" you can only hope to influence frequencies higher than 24kHz. Is that frequency range really a problem in your doors? On the other hand, for 200 Hz, you'd need a material that's at least 15" thick.
That's pretty much what I've heard so far, that ensolite on the outer door skin to reduce reflections and backwaves is purely ineffective and a waste of time, and why I only have dampener on the outer skin at this point, with MLV coming in the future.
 

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Well, as far as what I can gather to help the baffle, I've done the non-hardening clay already, with about 1 lb per door with some between the speaker itself and the 1/2" mdf baffle, then between the mdf and the inner door skin, and have dampened the inner skin. Would the only further step be to lay down some MLV on the skin and the door card to block a little more noise?
Sounds like a plan :)
 
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