Sound deadening

The_Vermonster

Well-known member
Planning a body off resto this spring so I have lots of little projects in the wings. One of them is sound deadening the massive volume of a 110. I'm thinking overkill is best. The plan was to use an adhesive dampener inside and a spray of some sort as a dual purpose undercoat and dampener on the underside of the floor and in the engine compartment. Then it's a tossup between carpet and rubber mats, based on available cash.

Has anyone undertaken a project of this nature? What materials have people used?
 

Wilboro

Well-known member
I've done basically the entire inside of my 110 with b-quiet ultimate. The bulkhead has it on both inside and outside.

I just added a layer of 5mm uxcell foam on top of the b-quiet in my roof.

I've also got the wright off-road mat system up front.
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
I was looking into Dynamat last year and figured out a few important things to know about that type of stuff.

First, most people do agree that Dynamat is the best, but most people agree that alternatives do the same job for vehicles like ours.

Second, if I'm not mistaken, Dynamat's own web site showed how their research proved that 30% coverage of any given panel is what is needed to reach 100% efficiency for what the product is supposed to do. It is not a sound absorbent material, although perceptively it has the same results. What these types of materials do is dampen the vibrations that are actually in the metal panel itself, which is what makes a lot of road noise -- the noise is the result of the vibration. But that is not all of the noise you hear in a moving vehicle. But if you dampen the vibration, you eliminate that type of noise, at least.

So when I put it in my truck I used about 60% coverage on any one flat panel (think of how many there are in a Defender!) and the difference is fantastic! The best example is on the bare metal doors in my Series truck. It makes the whole experience of opening and shutting the doors very much worth it. The door actually operates better, it isn't an assault on your ears just slamming the door when sitting inside, and it does have the effect of slightly eliminating whatever road noise from vibrations there was coming from those panels.

This leads to the third point, what you want to dampen actual ambient noise is some kind of foam insulation. I bought a roll of foam rubber with a very sticky backing that I am putting here and there and everywhere that I have a cavity. I am sure someone could find better stuff, and stuff it into places as well.

Final point is that you should use a combination of the Dynamat (or like) and foam rubber type of insulation. Unless you are putting in a high-end stereo unit, covering the entire inside of the car with Dynamat is actually a waste of money.
 

Wilboro

Well-known member
I was looking into Dynamat last year and figured out a few important things to know about that type of stuff.

First, most people do agree that Dynamat is the best, but most people agree that alternatives do the same job for vehicles like ours.

Second, if I'm not mistaken, Dynamat's own web site showed how their research proved that 30% coverage of any given panel is what is needed to reach 100% efficiency for what the product is supposed to do. It is not a sound absorbent material, although perceptively it has the same results. What these types of materials do is dampen the vibrations that are actually in the metal panel itself, which is what makes a lot of road noise -- the noise is the result of the vibration. But that is not all of the noise you hear in a moving vehicle. But if you dampen the vibration, you eliminate that type of noise, at least.

So when I put it in my truck I used about 60% coverage on any one flat panel (think of how many there are in a Defender!) and the difference is fantastic! The best example is on the bare metal doors in my Series truck. It makes the whole experience of opening and shutting the doors very much worth it. The door actually operates better, it isn't an assault on your ears just slamming the door when sitting inside, and it does have the effect of slightly eliminating whatever road noise from vibrations there was coming from those panels.

This leads to the third point, what you want to dampen actual ambient noise is some kind of foam insulation. I bought a roll of foam rubber with a very sticky backing that I am putting here and there and everywhere that I have a cavity. I am sure someone could find better stuff, and stuff it into places as well.

Final point is that you should use a combination of the Dynamat (or like) and foam rubber type of insulation. Unless you are putting in a high-end stereo unit, covering the entire inside of the car with Dynamat is actually a waste of money.

One of the reasons I went a bit crazier with my coverage, I also read the studies, was to deal with small pinhole areas that might leak noise, along seams etc. Plus there is the small amount of added insulation. I settled on the b-quiet ultimate because It gives almost the same performance as the dynamt for a lot less money (so you can afford to go nuts). It's also butyl based so no fear of an
asphalt smell.

The difference in panel resonance, door sound etc is actually shocking. Certainly adding a foam where you can will make a big difference, I really noticed it on my roof.
 

The_Vermonster

Well-known member
Final point is that you should use a combination of the Dynamat (or like) and foam rubber type of insulation. Unless you are putting in a high-end stereo unit, covering the entire inside of the car with Dynamat is actually a waste of money.

Dynamat has some great literature about why their products work as well as they do. Based on that I plan on using a combination of Dynamat and Dynapad style materials. The roof and doors I plan on filling with a foam to help as much as possible.


One of the reasons I went a bit crazier with my coverage, I also read the studies, was to deal with small pinhole areas that might leak noise, along seams etc. Plus there is the small amount of added insulation. I settled on the b-quiet ultimate because It gives almost the same performance as the dynamt for a lot less money (so you can afford to go nuts). It's also butyl based so no fear of an
asphalt smell.

The difference in panel resonance, door sound etc is actually shocking. Certainly adding a foam where you can will make a big difference, I really noticed it on my roof.

I actually have some samples coming from B-quite and Secondskin so I can check out their stuff. I was noticing there are a ton of little seams that aren't a perfect seal, and small holes throughout the cargo area. I need it to be as waterproof as possible so I hope the combination of that and good undercoating will help.
 

LR Max

Well-known member
I covered the interior of my 109 with Al's Heat and Noise Reducer. My 109 is ex-MOD, so it basically has no interior.

I noticed a significant drop in noise and heat. Its supposed to be the same stuff as what is in Lizard Skin, but cheaper. Like, $60/gal off amazon. If I was doing a body resto, I'd be spraying this stuff down before painting, easy. I rollered mine in, and probably not thick enough. But with all of the parts out and with a spray gun, it would be easy.

Personally I subscribe to Sound Deadener Showdown. If I was doing a defender resto, I'd probably be buying directly from them. But since I'm hodge podging my 109, I've found similar materials for sale at Home Depot. So I plan on getting the materials locally and just doubling up on MLV.

I'll still do Dynamat-type on the doors. It helps give them a more "solid" feel.
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
...I was noticing there are a ton of little seams that aren't a perfect seal, and small holes throughout the cargo area...

Yes. The holes and seams do seem to be a major source of outside road noise getting in, as well as heat. I remember the first day I had my Defender I drove it from B.C. to Portland on a 90 degree day. It was OK, but all along I-5 I had this jet of hot air shooting up from below my right leg! It was just the unsealed seam under the corner of the seat box basically scooping hot exhaust/engine air right out of the slipstream (as much as there is on a Defender) and right into my driver's seat!
 

The_Vermonster

Well-known member
Does anyone have sq. ft. measurements for various parts of the truck like bulkhead, seatbox, rear tub, ect? I need to start pricing some things out.
 

Wilboro

Well-known member
Does anyone have sq. ft. measurements for various parts of the truck like bulkhead, seatbox, rear tub, ect? I need to start pricing some things out.

I don't have exact dimensions but I used about 100-120 feet x 12"(standard width) of the b-quiet ultimate. Again I went the overdoing it route.

This went in the tub sides but not floor, the roof, seatbox, both sides of the bulkhead where it made sense, under the bonnet, in the doors, and a bit around the rear sliding windows.

On a 110 CSW.
 

rocky

NAS-ROW Addict
It?s amazing the number of tiny holes that seem to exist in these trucks. Then there are big ones, like the two in the engine bay on the brake pedal tower. Must be a grommet for those. I spent an hour or two Saturday adding more dynamat to the lower half of the bulkhead, transmission tunnel and footwells. Definite improvement. Makes me realize that I should have put some on the upper half of the bulkhead before I put the dash back...
Using my iPhone sound meter idle is runs around 72db highway 50mph up to 86db. Thats with noisy BFG MT.
 

rocky

NAS-ROW Addict
A question on closed cell foam-anyone know whether thicker makes a meaningful difference?
I've dynamated the roof, definitely made a difference.
Next step seems to be closed cell to absorb airborne noise. Thinner presumably helps if a headliner is the ultimate goal. But there's no point if thin stuff makes no meaningful difference. Kinda like to do this right the first time!
Thanks
 

MountainD

Technical Excellence Contributor
I have not installed it yet, but after I put on the Peel and Seal (butyl layer) I am going to install (on the roof) the 3M Thinsulate Acoustic (https://www.3m.com/3M/en_US/company...nsulation-SM600L/?N=5002385+3292659035&rt=rud ) This was recommended to me by an acoustic engineer turned high-end automotive sound deadening specialist many years ago. there are several online articles about what the various layers do but this one in particular has proven to be both effective and light which is great for the roof (particularly after the Butyl layer) The added "thinsulate" isn't going to hurt a darn thing either! I bought a roll off ebay about 5 years ago and the darn stuff is still waiting for install. When I pop the roof off to do the bulkhead, I will do it then... Someday...


There are a lot of choices--this one sounded best to me.
 

NPT90

Well-known member
Yes. The holes and seams do seem to be a major source of outside road noise getting in, as well as heat. I remember the first day I had my Defender I drove it from B.C. to Portland on a 90 degree day. It was OK, but all along I-5 I had this jet of hot air shooting up from below my right leg! It was just the unsealed seam under the corner of the seat box basically scooping hot exhaust/engine air right out of the slipstream (as much as there is on a Defender) and right into my driver's seat!

This is my current situation, I bought an R380 cooler to abate some of the heat but ultimately I need more insulation
 

CDN38

Well-known member

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NPT90

Well-known member
As much as I am not a big fan of some of the Britpart stuff... they do carry brand name items. One of them is pre cut Dynamat kits for Defenders. I have installed a couple of these kits before, well worth looking at.

https://www.britpart.com/parts/enhancements/defender/dynamat/

interesting, but is it cost prohibitive for what you get?

I guess if it saves you hours of cutting and measuring its worth something for sure, do they come labeled?
 

MountainD

Technical Excellence Contributor
Cool deal on that predone Britpart kits. But if anyone is on a budget and wants pretty darn near the same thing (plenty of internet challenges/comparisons on this one) it is hard to beat Peel and Seal. I even have it under my floor boards facing and near exhaust and it doesn't fall off. I don't smell it. It stays put and it is 3' wide by 33' roll for just over $100 shipped.



I know not everyone is on a budget, but I struggle just to get the parts I do without the wife taking my head off. She is just doing the 2017 taxes and is adding up the LS stuff... she was very grumpy last night...
 

The_Vermonster

Well-known member
I have not installed it yet, but after I put on the Peel and Seal (butyl layer) I am going to install (on the roof) the 3M Thinsulate Acoustic (https://www.3m.com/3M/en_US/company...nsulation-SM600L/?N=5002385+3292659035&rt=rud ) This was recommended to me by an acoustic engineer turned high-end automotive sound deadening specialist many years ago. there are several online articles about what the various layers do but this one in particular has proven to be both effective and light which is great for the roof (particularly after the Butyl layer) The added "thinsulate" isn't going to hurt a darn thing either! I bought a roll off ebay about 5 years ago and the darn stuff is still waiting for install. When I pop the roof off to do the bulkhead, I will do it then... Someday...


There are a lot of choices--this one sounded best to me.
"open cell" foam seems better overall for sound deadening. It's main weakness is that is doesn't do well with water. So a roof is a perfect place for it.

Sent from my Pixel 2 using Tapatalk
 

MountainD

Technical Excellence Contributor
"open cell" foam seems better overall for sound deadening. It's main weakness is that is doesn't do well with water. So a roof is a perfect place for it.

Sent from my Pixel 2 using Tapatalk


Not compared to the 3M or even fiberglass. For this layer of sound deadening, you actually want substances that are more open than open cell foam--something with more penetration such as fibers. Although better than closed cell foam, it isn't in the same league as the polyfill, 3M and other open substrates from the tests that I have seen.


Currently on my roof is closed cell foam--even worse! I just didn't know until I did a deep dive into it.
 
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