# Sounddeadening usefulness



## Just_Crazy (Nov 10, 2008)

Been doing a little research (searches) and have come across some debate over if sound deadening actually helps or not.
The main argument seems to be just buy a "quiet" car to begin with, which I agree, but after that do you still use sound deadening or just leave it alone.

So do you feel sound deadening is worth the money?


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## chefhow (Apr 29, 2007)

Sound deadening isnt just used to make a car quiet, its also used to keep panels, doors and trunk lids from rattling so you dont sound like some hood rat rollin down the street with his bass all "boom boomin" but all you can hear is that horrible trunk lid fart and liscence plate rattle...


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## sqshoestring (Jun 19, 2007)

I don't use much, even with an old 2x35w I can hear the music good with a window down and I use larger amps. What I do use it for is problem areas and around drivers, and to kill vibration/rattles. I put some on the rear wheel wells in this car for example, because I can hear the tires, I hear that with the music off. Used it in the doors and around my IB baffle and some on the floor.


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## John_Chricton (Apr 16, 2009)

Just_Crazy said:


> Been doing a little research (searches) and have come across some debate over if sound deadening actually helps or not.
> The main argument seems to be just buy a "quiet" car to begin with, which I agree, but after that do you still use sound deadening or just leave it alone.
> 
> So do you feel sound deadening is worth the money?


The ones who believed it would "quiet" their car are the ones who are generally disappointed by the results. Sound deadener will not quiet your car, at least not at the level some expect. It simply eliminates/reduces the nasty noises your car panels/chassis/etc will make when your speakers cause them to vibrate. In many cases buying a naturally quieter car will not help this. Throw in a subwoofer and it will rattle just like the rest. In this regard, I could not be happier with my choice use it. Some areas in my Sentra rattled/buzzed like crazy even with just the little 8" stock subwoofer.

There are products that will quiet your car, but they are entirely different from vibration dampening products.


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## sqcomp (Sep 21, 2009)

Hmmm...

I've come to a completely different conclusion. My vehicle has quieted down so much that the conversations at highway speeds can almost be whispered and still understood. The noise floor is dramatically lower in my case. One of my friends said that my car was quieter than a top of the line Mercedes (of which he's worked with on several occasions).

For me, it has been the most rewarding and apparent "mod" to my vehicle.


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## t3sn4f2 (Jan 3, 2007)

sqcomp said:


> Hmmm...
> 
> I've come to a completely different conclusion. My vehicle has quieted down so much that the conversations at highway speeds can almost be whispered and still understood. The noise floor is dramatically lower in my case. *One of my friends said that my car was quieter than a top of the line Mercedes (of which he's worked with on several occasions).*
> 
> For me, it has been the most rewarding and apparent "mod" to my vehicle.


That's definitely worth it. I can't wait for all-electric cars.


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## ANT (Oct 15, 2005)

Even before I started my company, I would sound deaden every car I owned.
That is just how important it is to me.
-Audio system gets louder (or appears louder because of lowered noise floor)
-Less driver fatigue
-Less rattels, squeaks and vibrations translates to a physical interpretation as a more solid ride
-Cell phone conversation and person to person conversations are more enjoyable
-Less obnoxious vibrations from mid bass and sub bass.. (music sounds bettter)
-Thermal insulation in some cases

Plenty of reasons to sound deaden your car.

ANT


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## fastlane (Apr 6, 2009)

I would never own another vehicle without adding additional sound deadening; whether it be a Lexus or Kia. 

That being said, there are certainly dimishing return on investments with it. You don't have to go completely overboard to realize a significant improvement (even though I did ).


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## t3sn4f2 (Jan 3, 2007)

fastlane said:


> I would never own another vehicle without adding additional sound deadening; whether it be a Lexus or Kia.
> 
> *That being said, there are certainly dimishing return on investments with it.* You don't have to go completely overboard to realize a significant improvement (even though I did ).


x2, you don't want to remove a thick layer of bonded cotton from a wheel well and put a layer CCF in its place. 

Work with what is there and add what is _needed_ only.


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## tintbox (Oct 25, 2008)

Very well put. That's exactly exactly what I've done over years. Over kill is not necessary except for peace of mind.


t3sn4f2 said:


> x2, you don't want to remove a thick layer of bonded cotton from a wheel well and put a layer CCF in its place.
> 
> Work with what is there and add what is _needed_ only.


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## GSlider (Jun 11, 2009)

My wife is asking why I'm going to deaden the doors and the hatch in our MDX. For the very reasons listed above. Quieter ride, overall better sound at lower volume, helps eliminate rattles.


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## sqcomp (Sep 21, 2009)

t3sn4f2 said:


> That's definitely worth it. I can't wait for all-electric cars.


...yeah, it is worth it. Yes, his advice is worth it. He's deep into the audio industry. I have worked right beside him on some of the nicer vehicles. I know how quite they are.

Sound deadening on my little subcompact Toyota have made a very noticable difference. Hands down.

You can take it or leave it. I care not.


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## JeremyC (Dec 20, 2007)

fastlane said:


> I would never own another vehicle without adding additional sound deadening; whether it be a Lexus or Kia.
> 
> That being said, there are certainly dimishing return on investments with it. You don't have to go completely overboard to realize a significant improvement (even though I did ).


I agree completly. My accord is my 3rd car I have deadoned the crap out of and I'm hooked. 

Kind of like auto start for the winter, or remote window roll down for the hot summers. 

As long as I can still afford my toys, I will have them in any car I own.


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## asawendo (Nov 22, 2009)

DIYMA said:


> Even before I started my company, I would sound deaden every car I owned.
> That is just how important it is to me.
> -Audio system gets louder (or appears louder because of lowered noise floor)
> -Less driver fatigue
> ...


Absolutely right... sound deadening makes your car more comfortable


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## chefhow (Apr 29, 2007)

I want to know who the 3 ppl that said No are and why they said it.


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## fastlane (Apr 6, 2009)

chefhow said:


> I want to know who the 3 ppl that said No are and why they said it.


I found them.


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## Oliver (Jun 25, 2007)

http://t3.gstatic.com/images?q=tbn:...ecache2.allposters.com/images/CSF/224-047.jpg

Is this them ?


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## fastlane (Apr 6, 2009)

a$$hole said:


> http://t3.gstatic.com/images?q=tbn:...ecache2.allposters.com/images/CSF/224-047.jpg
> 
> Is this them ?



No wait, here they are. 









OK, I think I'm done derailing the thread. Even though I think we all know the answer by now.


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## asumafu (Feb 25, 2010)

After deadening one car about ten years ago, I've done everyone of my cars since to include my Audi's. I won't go without it anymore. Deffinately worth the money


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## dbiegel (Oct 15, 2006)

I've done all my cars in the last ten years this way, and I've generally gone quite extreme in the past with great results. The best results I got was when I went all out -- stripped my entire interior including the dash, HVAC, everything down to the bare firewall etc. I covered the entire firewall area with 3-layer Sonic Barrier (basically a thicker, home version of Luxury Liner Pro, using MLV as a middle layer) -- to replace the factory dash and HVAC with custom ones. The entire body of the truck was done with many layers of Dynamat Xtreme and MLV...

It took me half a year, but the result was astonishingly quiet... I mean, much quiter than most of the $70k+ cars I've ridden in. Man, I miss my truck.  That was like 7 years ago... if I had the time to do custom dash and everything again on my more recent cars, I would do the same deadening in a heartbeat. My last car was a convertible so it was a waste of time mostly... though doing the doors properly got me some awesome midbass out of 6.5's.. On my Accord, I'm slowly but surely getting there, but I haven't done much on the firewall or roof yet.

The problem is, the results are NOT the same if you just do the typical deadening job (CLD on doors, floor, roof)... not even close. Your deadening is only as good as the weakest link.


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## Hernan (Jul 9, 2006)

If you are gona make a long drive, which car is better a Yaris or a Merecedes S?
Low noise is gooooood.


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## Greg S (Oct 21, 2009)

Hernan said:


> If you are gona make a long drive, which car is better a Yaris or a Merecedes S?
> Low noise is gooooood.


The Yaris! With the extra money you save on the price of the car and the gas you don't use you can deaden it to death. 




Actually I just happen to like small cars. I've never spent more than $25K on a car due to the fact that I know I will be taking it apart and modifying it. It's part of the fun of owning a car for me, making it my own.

But on topic, I think every car can benefit from some deadening. Obviously less expensive car need more, just take my xB. I pulled the headliner yesterdayt o change the fabric on it and there was absolutely no deadening material anywhere on the roof. 21 tiles of CLD later and it sounds a lot better. Now the rain doesn't make an echo.


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## sqcomp (Sep 21, 2009)

Someone say Yaris? 

I've got the back deck and the roof to finish for my deadening here in a month and a half. I still get 43 mpg regularly with all the deadening added.

Compare the cost to own the Merc or the Yaris. If you're concerned about money, you'd go with the Toyota.


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## Hernan (Jul 9, 2006)

sqcomp said:


> Someone say Yaris?
> 
> I've got the back deck and the roof to finish for my deadening here in a month and a half. I still get 43 mpg regularly with all the deadening added.
> 
> Compare the cost to own the Merc or the Yaris. If you're concerned about money, you'd go with the Toyota.


About money and realivity!!

But, as a system platform the heavy car is without doubt a better start.


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## sqcomp (Sep 21, 2009)

There's more to a good system platform than the weight...IMHO

I enjoy the Yaris dash setup, seeing as the dash is a good size with center gauges. It's also very easy to work on with good quality workmanship put into the construction.


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## Just_Crazy (Nov 10, 2008)

So, what your saying is sound deadening is important.


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## sqshoestring (Jun 19, 2007)

chefhow said:


> I want to know who the 3 ppl that said No are and why they said it.


Certainly if you_ want_ a quieter car then you want to deaden it more. If you want a 160db sub in your car you put one in. Most of my cars I have not noticed a lot of noise so I don't bother, I don't feel I need it for the stereo when it will blow all the road noise out of the car at 1/4 volume, and that is with 70rms/ch, even 50rms can easily do it. I don't spend hours in my car these days either, which can make a difference in what you want. When I was a kid and had some 70s muscle cars, sure I used to put whole floor insulation in them because they were loud inside, though my stereo was much louder. Could not buy the stuff then, so I hocked it out of full size luxury cars in the bone yards and it worked great. So guess the cost is worth it *if* you want a quieter car, and at the bone yard the cost can be very low, lol. But my much newer cars today are far quieter than those old cars.


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## Oliver (Jun 25, 2007)

Just_Crazy said:


> So, what your saying is sound deadening is important.


If U mass load the big panels in your car , you'll lose the 7-Eleven rattle


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## lil goat (Oct 16, 2009)

I think maybe some clarification is needed, there is vibration damping, IE dynamat and the like, then there is sound deadening. For years and it seems even today many think dynamat it all it takes, it will reduce buzz, but does little to quiet the road noise. You need some kind of barrier for that, like MLV and closed cell foam, or lead. I have a convertible, and the difference the full treatment had was amazing. I did just vibration damping first, that didn't do much. When I added the MLV and foam, WOW, especially to the floors. I road in a friends car last weekend same car as mine, he has done the truck and I haven't yet, very noticeable difference. I need to do my trunk soon. Then I will start on my truck, I am hooked!


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## jimbno1 (Apr 14, 2008)

I will let you know as soon as I do my truck. On the other hand I plan very little sound treatments for my old Lexus, as it is pretty quiet already.


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## Kpg2713 (Feb 10, 2008)

sqcomp said:


> There's more to a good system platform than the weight...IMHO
> 
> I enjoy the Yaris dash setup, seeing as the dash is a good size with center gauges. It's also very easy to work on with good quality workmanship put into the construction.


Are you really comparing a Yaris to an S550 Merc? I'm sure if you drove the Merc for a month you wouldn't be praising the dash on a Yaris. Regardless, I am pretty sure I wouldn't deaden much in any newer luxury cars. A little here and there, but I feel deadening is mostly for older and cheaper cars. Going down the highway in something like a Bentley Conti GT, I wouldn't even know where to start in improving the sound deadening in that...


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## WAwatchnut (Sep 5, 2009)

Just_Crazy said:


> The main argument seems to be just buy a "quiet" car to begin with, which I agree, but after that do you still use sound deadening or just leave it alone.
> 
> So do you feel sound deadening is worth the money?


It depends on the car - if you start with an extremely quiet car, it may not be worth the extra money. But in most cases, even with a good, quiet car to start with, you can strategically apply deadening to resolve trouble spots.

A good quiet car means you won't need to spend much to address any specific issues, so it will probably be worth it to fix the issue. And a noisy car will cost more quiet down, but the results will be more dramatic, so it's still worth it. But if you start with a quiet car, and apply a bunch of deadening material, the results may not be worth the money.

Personally, how quiet the car is is a consideration when I buy a car, but it's pretty low on the priority list... Fixing a noise problem is much easier than fixing a handling, power, or cost issue.


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## IrishPilot (Jan 31, 2010)

DIYMA said:


> ...
> -Audio system gets louder (or appears louder because of lowered noise floor)
> -Less rattels, squeaks and vibrations translates to a physical interpretation as a more solid ride
> -Less obnoxious vibrations from mid bass and sub bass.. (music sounds bettter)
> ...


I just sound deadened my vehicle. First time I have ever done it. I definitely agree with these that Ant has listed. I didnt notice a drastic decline in road noise (nor did I really expect it). I did however find a noticeable improvement in both sound volume as well as quality (presumably from sealing up access holes in the door, etc.). Since my vehicle is still fairly new, I didnt have too many rattles etc., but those which I did have were eliminated and Im confident that if I get any more that I can resolve them immediately.

For what its worth, I only did the doors and the rear wall of my double cab truck. I would definitely do it again.


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## The A Train (Jun 26, 2007)

now for those using SPL tiles, CCF, and MLV, is there a preference to order it is laid to yeild better effectiveness? obviously SPL tiles first, but CCF or MLV next?


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## ANT (Oct 15, 2005)

SPL TIles first
Foam Second 
MLV Last

ANT


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## The A Train (Jun 26, 2007)

ok thanks, thats what i was thinking


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## nastyfacials (Jan 20, 2010)

hm. this poll is pretty one-sided. but i have an intake, exhaust, header, low pro tires etc. i'd have to sound-deaden the WHOLE cabin to get the benefits. i didn't vote but i'm not sure if it'd be worth the money in my situation.


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## mda185 (Dec 14, 2006)

I have two specific experiences with sound deadening that won me over. Keep in mind that neither of these cars was quiet to begin with. 

I have a 1992 Celica All Trac turbo that has minimal sound deadening from the factory. When I upgraded to 3" diameter exhaust components, the noise level went up dramatically and there was a bad resonance at highway speeds. I could not hear the stereo or the passenger most of the time. Application of SPL tiles and foam in the rear parcel area and inside the rear quarter panels reduced the noise enough to make the car driveable at highway speeds again. It did not make it quiet but took enough of the edge off to make me happy. The foam layer was critical to making this work. I intend to apply SPL tiles and foam to the rest of the car this year.

Second application is in a 2001 Nissan Pathfinder. I treated the front doors with SPL tiles and foam on the door skin. I also made a replacement for the thin plastic moisture barrier out of MLV. The noise reduction in the front seats was dramatic. I think the main improvement was reduction of higher frequency noise that was coupling into the windows. I suspect the foam layer on the inside door skin absorbed a lot of sound that was reflecting off of internal sheet metal, coupling into the window support structure, and being radiated into the passenger cabin. I will extend this treatment to the rest of the Pathfinder this year.


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## Patrick Bateman (Sep 11, 2006)

Can someone post measurements which show an improvement in road noise? The only independent measurements I've ever seen showed little to no improvement.* This is consistent with my own experience. I have sound deadened three of the five cars that I've owned, and all saw little to no improvement.

My current car uses no additional sound deadening, and I do not intend to ever apply it again. It's not worth the trouble.

Also, I was able to make a *huge* improvement in NVH by switching to a tire which is optimized for a very quiet ride. (Goodyear Comfortred.)

The improvement was unmistakable.

* CA&E and CSR measured cars with deadening in the 90s. One was a Jetta and one was a Camaro. IIRC, the Jetta saw a small improvement and the Camaro saw no improvement at all. Dynamat has published measurements which show a change, but I think their bias is obvious.


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## ibanzil (Jun 29, 2008)

^^^^ +1 on the tires. Made my car much more enjoyable to be in.


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## tplaya07 (Mar 6, 2010)

I just love playing in the Spectrum Sludge....purple gooey goodness


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## enerlevel (Jun 6, 2009)

i just borught an old suv. its not very quiet as new cars........
what r the best places to apply deadening in order to get a quieter ride?
i mean places which would give me the most audible change


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## Rudeboy (Oct 16, 2005)

enerlevel said:


> i just borught an old suv. its not very quiet as new cars........
> what r the best places to apply deadening in order to get a quieter ride?
> i mean places which would give me the most audible change


First things to check on an older vehicle are the weather seals, especially around the doors, and the motor mounts. If you have problems in those areas, no amount of sound deadening will help.


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## tplaya07 (Mar 6, 2010)

I think it really depends on what kind of "noise" you're trying to eliminate. Hopefully ANT or one of the vets will chime in and correct me if I'm way off base, but...

If you're looking to eliminate road/engine/wind type noises, you're likely going to want to use some sort of open cell foam (preferrably with think vinyl backing). These foams act similar to those crazy looking "squiggly" walls you see in recording studios, which absorb/reduce sound waves. These open cell foams are great EVERYWHERE in the cab of your car, as the more you add, the more of a barrier you create between the quiet interior and noisy exterior (wind, engine, wheels, etc.)

Sound dampers and sludge are primarily used on large, thin pieces of metal to add weight to them and reduce rattle/vibration. There are great examples of this on youtube if you search for SecondSkin. If you take a large, thin piece of plastic and drop it on the ground, it will be loud (and tinny sounding) from the reverberation (<--correct term??). However, when you add some weight to that piece of metal, it changes the dynamics of it, and the added weight dissipates that reverberation much faster...so you end up hearing more of "thud", than a clanky, tinny sound (I think this is lowering the resonant frequency is what it's called). A vehicles roof and/or trunk is a great example of this. We've all heard those cars with subs in the trunk with no deadening/dampner...it sounds like crap because of that huge piece of metal (trunk/roof) vibrating. Simply adding weight to those panels/metals will eliminate a majority of that.

Dampers can also be used for reducing things mentioned in the second paragraph (wind/engine/etc.), but do so in a little different way. I believe these type materials absorb some of the noise primarily because of their thickness/denseness. If I stand a foot away from you and yell at the top of my lungs, it's going to be loud. If I do the same thing, but place a large paper bag between us, you might notice the sound level diminish minutely...but not likely much of a change. However, if I stood a 1" thick piece of MDF between us, now you're going to notice a significant difference in sound level. 

I know there is quite a bit more to it than this, but I believe this to be the basic fundamentals of each material. Again, hopefully the pros will chime in if I'm way off base.


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## pionkej (Feb 29, 2008)

tplaya07 said:


> I think it really depends on what kind of "noise" you're trying to eliminate. Hopefully ANT or one of the vets will chime in and correct me if I'm way off base, but...
> 
> If you're looking to eliminate road/engine/wind type noises, you're likely going to want to use some sort of open cell foam (preferrably with think vinyl backing). These foams act similar to those crazy looking "squiggly" walls you see in recording studios, which absorb/reduce sound waves. These open cell foams are great EVERYWHERE in the cab of your car, as the more you add, the more of a barrier you create between the quiet interior and noisy exterior (wind, engine, wheels, etc.)
> 
> ...


Kudos on the detailed post, but Rudeboy (the guy who just posted before you) is a "vet". He owns sounddeadenershowdown.com. Just an FYI.


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## pionkej (Feb 29, 2008)

Patrick Bateman said:


> Can someone post measurements which show an improvement in road noise? The only independent measurements I've ever seen showed little to no improvement.* This is consistent with my own experience. I have sound deadened three of the five cars that I've owned, and all saw little to no improvement.
> 
> My current car uses no additional sound deadening, and I do not intend to ever apply it again. It's not worth the trouble.
> 
> ...


I'm surprised by this comment since you seem to focus on the "why" whether something does or doesn't work until you have an answer. Do you mind me asking what method you used to test for the reduction or lack thereof? What did you use to deaden the car? Most people Also, does anyone know what method Car and Driver uses to test ambient noise levels? I'm just curious because if luxury cars are quieter than economy cars, SOMETHING has to reduce noise. 

NOTE: I believe CLD/CCF/MLV when applied properly will help reduce noise. I just want to forward the discussion on how to test for it.


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## tplaya07 (Mar 6, 2010)

Yeah...I know. I used to read (and direct people to) Rudeboy's website years ago back on CA.com and SoundDomain. I used to own an audioshop myself about 3-4years ago, and was a dealer for SecondSkin/ANT. I am familiar with the products, but by no means claim to be a pro about the technicalities of how it all works...which is why I suggested any pros/vets chime in and correct my post if it contained any misinformation.


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## BigAl205 (May 20, 2009)

Patrick Bateman said:


> Can someone post measurements which show an improvement in road noise? The only independent measurements I've ever seen showed little to no improvement.* This is consistent with my own experience. I have sound deadened three of the five cars that I've owned, and all saw little to no improvement.
> 
> My current car uses no additional sound deadening, and I do not intend to ever apply it again. It's not worth the trouble.
> 
> ...


I've got the "before" measurements, I just haven't finished. My original RTA measurements were: engine off; engine on without A/C; engine on with A/C; travelling 30 MPH; and travelling 70 MPH. So far I've installed CLD tiles on everything except the roof, and put down foam and MLV on the rear hatch area and floor. I still need to hang MLV on the doors, hopefully this weekend.


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## CobraVin (Jul 31, 2007)

Patrick Bateman said:


> Can someone post measurements which show an improvement in road noise? The only independent measurements I've ever seen showed little to no improvement.* This is consistent with my own experience. I have sound deadened three of the five cars that I've owned, and all saw little to no improvement.
> 
> My current car uses no additional sound deadening, and I do not intend to ever apply it again. It's not worth the trouble.
> 
> ...


I'm really surprised by your comments, I'm a big fan of your threads and the attention to detail of your experiments to gain even a little improvement in sound quality. But it baffles me how you couldn't notice a difference. 
*UNLESS, your strictly talking about deadening products like dynamat, because the noise blocking items(i used a product that is 1/4"ccf with 1/8 mlv attached to it)are immediately apparent. If your talking more about dynamat type products i think they are overused in areas that are not prone to vibrations or flexing to begin with, and may not make a noticeable improvement in road noise reduction. I think it depends on what product your using and for what purpose.

These are the before and after results for my last car (c6 corvette) this was using a radio shack hand held decibel meter, i also used my mic and rta laptop setup to record info but i gave my old laptop to a friend, and i don't know if those graphs are still there.

before a weighted idle........ 67... AFTER 57
before a weighted 60mph.....77... AFTER 71
before C weighted idle.........87... AFTER 77

i think thats a huge improvement, i did the entire floor up the firewall as far as i could go, up and over the the back wall and the rear cargo area, as well as taking down the rear inner fender liners and putting it in there as well(it already had some from the factory in there)


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## Maglite (Dec 28, 2009)

Every car needs sound deadening....at least 2 boxes...the big ones


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## CobraVin (Jul 31, 2007)

i also covered all the MLV seams in lead tape, as well as covered the tranny tunnel in lead tape, i also used deadening under the mlv


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## Patrick Bateman (Sep 11, 2006)

tplaya07 said:


> I think it really depends on what kind of "noise" you're trying to eliminate. Hopefully ANT or one of the vets will chime in and correct me if I'm way off base, but...
> 
> If you're looking to eliminate road/engine/wind type noises, you're likely going to want to use some sort of open cell foam (preferrably with think vinyl backing). These foams act similar to those crazy looking "squiggly" walls you see in recording studios, which absorb/reduce sound waves. These open cell foams are great EVERYWHERE in the cab of your car, as the more you add, the more of a barrier you create between the quiet interior and noisy exterior (wind, engine, wheels, etc.)



When you look at the foam tiles in a studio, you might think that they're physically absorbing sound, but looks can be deceiving. It's the *shape* of the tiles that's important. In fact you can make acoustic tiles out of anything really. Wood, glass, plastic, whatever. And in a car, open cell foam works differently, because it's not physically exposed.

Before I go off into the weeds, I would recommend reading a couple of books on this subject. These are the two that I have personally read, and they are both very good:

Amazon.com: Master Handbook of Acoustics (9780071603324): F. Alton Everest, Ken Pohlmann: Books









Home Theater

Isolating a room is a complex subject; I really can't do it justice with a post on the internet. The Geddes book covers the subject nicely, and the Everest book covers the concepts from a "birds eye" view.









Using open cell foam in a vehicle to absorb sound isn't an effective way to quiet it down. The most effective use of open cell foam in a vehicle or in a home theater is to create a "room within a room." So you want three layers here:


The first layer is the skin of the car itself
The second layer is open cell foam. While it may attenuate sound to a small degree, it will not be particularly effective. But what it WILL do is isolate the third layer from the second.
The third layer is critical. If you only use two layers, you're not using the foam effectively. The third layer is a physical barrier that's isolated from the first layer by the open cell foam.









The graph above is an excellent example of how well this works. It compares three different configurations. One uses a single sheet of drywall. The next uses two sheets of drywall. The third (and most effective) uses two sheets of drywall, with their "acoustiblok" product sandwiched between the two layers.

Here's the important part:

_The important part is that the two layers are isolated._ If you want to eliminate noise, isolating the two panels is very effective.

You can see this in the graph above. Two layers of drywall are better than one layer, but isolating the first from the second makes a MASSIVE improvement. It's the same thing in a car. You can pile on ten thousand pounds of sound deadener, but the law of diminishing returns is going to rear it's ugly head. Isolation is very effective. It isn't a coincidence that Mercedes Benz uses dual pane glass in it's top of the line cars.

Note that creating a "room within a room" works differently than deadening the walls. Sound deadening reduces the resonant frequency of the panel, and increase it's STC slightly. What's presented above is a different approach entirely. Also, the two approaches can be combined.


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## CobraVin (Jul 31, 2007)

the product i used has that third layer you reference, its the 1/8th inch Mass Loaded Vinyl that is the blocker, its 1lb per foot, the closed cell foam acts as the decoupler to the car, i taped the seams in the MLV with another effective blocker(lead) so the noise doesn't come through the seams, the foam alone has no real road noise blocking, at least it didn't for me in a previous install, but with the mlv and foam it was incredible how much it helped


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## pat_smith1969 (Feb 17, 2010)

So what product do you use CobraVin? 

I am getting ready to do a sound deadening install and find the Second Skin stuff extreemly expensive when you add the Damp pro + Overkill Pro + Luxury Liner Pro... also It would be nice to have an all in one product I think.

I love my car (MazdaSpeed3), but to save weight they added literally NO sound deadening (other than carpet). Under the car is plain sheet metal, under the carpet is plain sheet metal. SO I can really benefit from a good install.


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## cceast1 (Mar 31, 2010)

worth the money


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## CobraVin (Jul 31, 2007)

pat_smith1969 said:


> So what product do you use CobraVin?
> 
> I am getting ready to do a sound deadening install and find the Second Skin stuff extremely expensive when you add the Damp pro + Overkill Pro + Luxury Liner Pro... also It would be nice to have an all in one product I think.
> 
> .


i forget the company i got it from, wasn't cheap its like luxury liner 

from what i hear the second skin stuff is real nice, if you want to save money skip the overkill since the luxury already has a foam layer on it anyway, also just use the damp pro where you really need it like on panels that flex and vibrate a lot, the biggest road noise reduction is gonna be from the luxury liner imo

thats why you cant just use one product cause they all work differently, the damplifier needs to be well stuck to the metal and the barrier mlv needs to have the foam to decouple it from the surface

there are lots of good posts in here from over the years by people that are much better at explaining it all, do a quick search and you'll be reading for hours, good luck


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## krisfnbz (Apr 30, 2008)

pat_smith1969 said:


> So what product do you use CobraVin?
> 
> I am getting ready to do a sound deadening install and find the Second Skin stuff extreemly expensive when you add the Damp pro + Overkill Pro + Luxury Liner Pro... also It would be nice to have an all in one product I think.
> 
> I love my car (MazdaSpeed3), but to save weight they added literally NO sound deadening (other than carpet). Under the car is plain sheet metal, under the carpet is plain sheet metal. SO I can really benefit from a good install.


I had a great experience with Don from www.sounddeadenershowdown.com. Check out my thread: HERE

You cant go wrong with Don!


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## instalher (May 13, 2009)

well both my cars are honda civics... my 03 four door got the whole treatement..... thats 7 bulk cases of dynamat extreme.. 6boxes of dynalyner.... four boxes of tac mat...... plus a case of mono expanding foam.. is my car quiet damn right... can i justify the cost... hell no!!!! now i have tried just the doors..... no improvement... then all interior.... small improvement but still to expensive... then i did the hood, trunk, trunk lid, and back parcel shelf,.... small bit better... then the roof.... ok now its good... but the biggest improvement,BY A LONG SHOT, was having the headliner redone in alcantera suede.... man did that ever eat alot of soundwaves... unreal... iam 12 db quieter at 60mph now with the soundproofing....


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## krisfnbz (Apr 30, 2008)

instalher said:


> well both my cars are honda civics... my 03 four door got the whole treatement..... thats 7 bulk cases of dynamat extreme.. 6boxes of dynalyner.... four boxes of tac mat...... plus a case of mono expanding foam.. is my car quiet damn right... can i justify the cost... hell no!!!! now i have tried just the doors..... no improvement... then all interior.... small improvement but still to expensive... then i did the hood, trunk, trunk lid, and back parcel shelf,.... small bit better... then the roof.... ok now its good... but the biggest improvement,BY A LONG SHOT, was having the headliner redone in alcantera suede.... man did that ever eat alot of soundwaves... unreal... iam 12 db quieter at 60mph now with the soundproofing....


Damn 12db is alot.


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## vrdublu (Apr 13, 2009)

Until my recent build I had never used sound deadening, but after reading post after post after post of how good it is and all the benefits I gave it a try. Not only did I sound deaden but I used a sound insulator also, although I don't really see night and day differences as far as road noise goes I have noticed the increased mid bass and rattling down signifcantly. Was it worth the $200, I would say "yes". Will I do it again, I would say "yes".


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## coefamily (Sep 24, 2009)

I think diminished returns is a correct Evaluation:
In a 50g car (BMW, audi, etc) it is not particularly noticable.

In a 12000 Civic is makes a Huge difference.


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## dbiegel (Oct 15, 2006)

coefamily said:


> I think diminished returns is a correct Evaluation:
> In a 50g car (BMW, audi, etc) it is not particularly noticable.
> 
> In a 12000 Civic is makes a Huge difference.


That's not necessarily true. Some high priced cars have thick, double-pane glass and triple window seals which give enormous potential to sound proofing. The relatively thin, single-pane glass of a $12,000 Civic will always be a limiting factor, no matter how much sound deadening you do.


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## terranova (Apr 11, 2010)

deadened my doors and the cab of my truck and got rid of a lot of my rattles lol


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## guilty (Apr 16, 2010)

yup me too..have just deadened the rear trunk... noticed a lot of difference...in my opinion yeah its worth it...

because sometimes one cant opt to go with a quite vehicle to start with so ya have to do with what ya got


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## MantaOwner (May 15, 2007)

Sound deadening is definitely worth it but no need to go over the edge with it. If your system costs like $1000 or more then spending $100-200 on sound deadening is totally ok IMHO. If you have mids in front doors then its a must to do the front doors. Other areas in a car depend on a car to some extent but I would say areas around the wheels and the firewall would be the next spots to take care of.

Tõnu


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## rhystard (Apr 15, 2010)

i certainly don't have a ton of experience deadening, and there's a reason.

it all depends on what you like. i'm a car enthusiast first. i love all sounds, including that of a 2.0 16v coming onto cam at 5600rpm and screaming all the way to 8k, including the little brap of fire between shifts :laugh:

in a couple of my previous rides, i've removed ALL of the sound deadening in the car and only installed it strategically to resonant areas to do with the stereo system. one of the most visceral "sound" experiences i've had was riding in a vw rabbit with a full cage, and a 150hp 1.8L 8v engine running on suzuki GSXR throttlebodies. you could feel the growl of the intake in your chest at 7krpm, mixed with the pinging of gravel off of the floorboards. just awesome.

i'm past this point in my life currently, and i don't mind the weight of factory sound deadening plus a little bit aftermarket, but you get the idea.

i personally cut out airboxes, remove mufflers, etc to make the CAR sound better.

an 8" square on a door panel can be all it takes to remove the resonance from a speaker (these cars had puny little HU driven stereos, to be honest).

i'm currently doing my doors due to the installation of mid drivers in the lower door panel, and have used about 2 sq foot on the outer door skin and inner door skin, coupled with the factory open cell foam reapplied after the vapour barrier has been reinstalled. i'll probably use another sq ft or so on the inner door panel depending on where it resonates when i pound on it.

my complaint about new cars is that you CAN'T hear the engine or exhaust at all. you'll notice that new GTIs have devices in plate to actually transmit some of the "good" engine noise to the cabin.


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## don_chuwish (Oct 29, 2009)

Patrick Bateman said:


> Can someone post measurements which show an improvement in road noise? The only independent measurements I've ever seen showed little to no improvement.* ...


I had a lot of fun putting CLD and MLV in my car to try for a road noise reduction. Kind of an OCD project to be sure. But I'm with Patrick on this one - I'd like to see some comprehensive before/after results with multiple car models, install details, etc., showing what matters most and where the key benefits were gained. A proper independent scientific study in other words.
I didn't see much measurable change in road noise myself, but I'm willing to blame the install before the product. Some cars are just easier to get a good unbroken layer of MLV onto the floor, wheel wells and firewall. Not so much with my car.

- D


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## instalher (May 13, 2009)

i will do such a test and post results.... i will use 03 honda civics and will provide complete details of procedure and results.. stay tuned....


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## CobraVin (Jul 31, 2007)

don_chuwish said:


> I had a lot of fun putting CLD and MLV in my car to try for a road noise reduction. Kind of an OCD project to be sure. But I'm with Patrick on this one - I'd like to see some comprehensive before/after results with multiple car models, install details, etc., showing what matters most and where the key benefits were gained. A proper independent scientific study in other words.
> I didn't see much measurable change in road noise myself, but I'm willing to blame the install before the product. Some cars are just easier to get a good unbroken layer of MLV onto the floor, wheel wells and firewall. Not so much with my car.
> 
> - D


on page two i posted before and after results from a decibel meter and have described what i did and how in my other posts, I'm sure there are more detailed test results somewhere but those numbers sure impressed me enough that I'm going to do the same thing on my new truck including taping the seams with lead tape(great noise blocker) if you you a noise blocker and don't have good coverage or leave gaps the noise will come right through the gaps, if it didn't work the first time i would not do it again, i will post results again as well


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## NRA4ever (Jul 19, 2010)

Its worth it to me. I deadened my old 97 F150 roof, floor & cab with dynamat deadener & foam products & cascade liquid deadener. I changed out my flowmasters for magnaflow mufflers & had a truck so quiet it was like a much more expensive brand. I got lucky & bought a bunch of shipping damaged dynamat real cheap. I didn't care if the boxes were bent & some of the mat wrinkled since it was less than half price. I had 6 boxes left over that I used in my Ranger. I have the doors& cab walls done to the windows in my Ranger.I can tell its quieter & will be much better once I do the floor.


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## Cruzer (Jul 16, 2010)

When i have my radio at normal listening volume, i cant hear anything outside my truck. Im not gonna say sound deadening wouldnt help, but i dont think its really needed. If i cant hear sirens, wtf is deadening gonna do


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## usmcsoldriver (Aug 13, 2007)

don_chuwish said:


> I had a lot of fun putting CLD and MLV in my car to try for a road noise reduction. Kind of an OCD project to be sure. But I'm with Patrick on this one - I'd like to see some comprehensive before/after results with multiple car models, install details, etc., showing what matters most and where the key benefits were gained. A proper independent scientific study in other words.
> I didn't see much measurable change in road noise myself, but I'm willing to blame the install before the product. Some cars are just easier to get a good unbroken layer of MLV onto the floor, wheel wells and firewall. Not so much with my car.
> 
> - D


I'm surprized no one caught this. The problem is that you just used
Cld and mlv. No ccf layer in between? Without it the mlv layer is pretty much a waste of money.


To take this in a related direction we should talk some about sound absorbtion options. Ie. Covering your doors and other panels in carpet.... Or phaux suede...

Thoughts?

Additionaly, can someone explain how to layer the wheel wells? Is this done on the outside of the cae? If so how do you keep from falling off.


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## Second Skin (Aug 5, 2010)

CobraVin said:


> i forget the company i got it from, wasn't cheap its like luxury liner
> 
> from what i hear the second skin stuff is real nice, if you want to save money skip the overkill since the luxury already has a foam layer on it anyway, also just use the damp pro where you really need it like on panels that flex and vibrate a lot, the biggest road noise reduction is gonna be from the luxury liner imo
> 
> ...


Hey, i'm Second Skin's new rep for the forums

you actually don't need to use Overkill Pro at all if you go with the Luxury Liner pro to take care of the airborne noise. Overkill Pro is mainly use to decouple the regular Luxury Liner, as well as a few other miscelaneous(SP?) uses.

Ken


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## adrenalinejunkie (Oct 17, 2010)

It may be, but you'' probably get better results by sealing up the holes (not the rain holes) that are on the doors. Sealing up the door should improve mid bass. As far as for quieting the car check out MLV/CCF materials. Also, making a baffle may help calm down rattles.


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## antikryst (Feb 26, 2011)

just had my doors fully deadened! not a night and day difference but its well worth it.

when i had focal v30s installed on my ford fiesta... no deadening was used apart from a tile behind the speaker. inner door was also a solid piece of plastic with no holes so i thought that was good enough. 

now... my outer door is fully deadened. inner door was reinforced where it could be without interfering with the window motors. mid bass increased just by a bit (since i had no big gaping holes to start with) but rattles are now gone. just by doing the doors... didn't notice much improvement in road noise. guess since i had no big gaping holes to start with.


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## Sine Swept (Sep 3, 2010)

"I used several layers of deadener" - I read this all the time and wonder why?

If you layer a piece of sheet metal and it still rattles - you are not working on the right side.


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## Wattser93 (Mar 12, 2010)

Sine Swept said:


> "I used several layers of deadener" - I read this all the time and wonder why?
> 
> If you layer a piece of sheet metal and it still rattles - you are not working on the right side.


I think they use multiple layers to help provide a noise barrier also, rather than just to stop rattling.


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## Schizm (Jun 12, 2011)

CobraVin said:


> i forget the company i got it from, wasn't cheap its like luxury liner
> 
> from what i hear the second skin stuff is real nice, if you want to save money skip the overkill since the luxury already has a foam layer on it anyway, also just use the damp pro where you really need it like on panels that flex and vibrate a lot, the biggest road noise reduction is gonna be from the luxury liner imo
> 
> ...


Luxury liner no longer has foam attached. Edit: But luxury liner pro does


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## Bampity (Nov 2, 2010)

Definitely worth the money.
Even the unknown brand stuff I bought on ebay for really cheap was a major improvement.


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## Joehs (Apr 27, 2010)

100% it's worth it. I recently saw the light with deadening and I won't go another system without it.


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## 8675309 (Jan 8, 2007)

The more you have the better you will be! You should be able to kick your door and not dent it! If it was not important then people would not build high end enclosures that weigh as much as a truck or use 3 inch baffles, lead, or multiple other make it strong products.


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## BigAl205 (May 20, 2009)

You should carve your whole car out of a solid block of butyl


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## sam_b03 (Feb 3, 2011)

My 370Z was terribly loud from tire and wind noise. I think they tried to save weight by scimping on the deadener. I deadened the hatch area and the doors behind the speakers. I guess I got the driver's side better because you can really hear the music playing much louder on the passenger side of the car from the outside.


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## rush985 (Dec 29, 2011)

Just wanted to say, as a new member, this is a great thread. Most people don't know the benefits of sound deadening in a car audio application and think just adding speakers to their stock doors will change everything. Unfortunately, upgrading your door speakers usually requires a little more work, like adding sound deadening/dampening.


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## adamtwo4 (Jan 8, 2012)

So my question is this:

I have a Jeep Wrangler (Softtop) but it is LOUD on the freeway. I know just putting in deadener won't do anything (since it is road/tire noise) so I am just looking for a way to quiet it down a bit to make my drive bearable. Will the 25% deadener, then adding foam and MLD route work for me to tone it down a bit, (I know it will never be a luxury car) or am I chasing something that will never occur? I'm pretty sure it is mainly tire/road noise coming from under the car.

Has anyone done somthing with a Jeep with good results?


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## sam_b03 (Feb 3, 2011)

My friend in high school had CJ7 with a soft top. Think what would have helped the most was putting foam where the canvas whips against the roll bar.


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## Hyperguy (Jan 15, 2012)

I did all the doors in my Tundra and while it didn't do much for "road noise", it did wonders for my mid bass. It's kind of a pain to do but definitely worth the effort!


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