Sound deadening, sound proofing - which have you done and what are your results?

Trying to do some research on sound proofing / sound deadening, best practices, areas to pay attention to and what to avoid. A preliminary search brought up some posts here on SS and online, but really no comprehensive collection.

For all those that used Kilmat, Fatmax, Lizard skin, Dynamat, Hushmat, or any generic brand, maybe you would like to share your experience for the rest to benefit from?

Mainly, which materials have you used, such as liner sheets, spray on, roll on? What brand? Cost per square foot. Preparations needed ahead of application? Results? What areas are most important? Benefits such as heat insulation as well? Are there sound absorption materials worth the application like exclusively in the engine compartment?

Also, post a few pics if you still have them.

Thanks in advance.

Not that I am a pro or experienced, but I used Kilmat 80 mil 36 sqft Car Sound Deadening Mat. No need to by the brand name expsensive stuff. Took about 3 boxes. Very easy install. Just vacuum and wipe down to get as much dirt/dust out as possible. Then use a roller to throughly press into place.

Covered with marine carpet. Did all areas, dog house, center tunnel, tailgate, rear, front and middle floor boards, sides. Did not do top.

Very happy with how much noise it killed. And it definately got rid of some of the heat too.

No messy glues or sprays,. Only negative is that if you want to remove it, you are going to have to use dry ice to get it off, so expensive to remove and a ton of work.

I used kilmat inside the doghouse (between the fiberglass and the heat shield) and 1" thick horse stall mats on the tunnel and floor.

While you can do much, much more than this, it still made a pretty good difference. You can hold a conversation without needing the intercom system, and the noise is not uncomortable for long trips.

I’ve been trying to soundproof mine. Most of the noise comes from the engine, obviously.

I built a second doghouse, similar to the console in the Hummers. I’m not done but I did test it. I put pieces of scrap foam cushions inside. That has seemingly been the most effective thing I’ve done. If you have a non turbo truck, buying a turbo dog house cover and then filling all that space with some kind of sound blocker material could be a great option.

I used siless liner products and put down some of that. Similar to killmat. In a humvee, the tunnel is plenty solid and doesn’t need it. A few pieces on the floor is enough to be effective.

I have a hard top and hard doors. My ears hurt so much less if I drive with the windows down. My *theory* is that the sound just bounces around in the tin can, where’s it can escape out the window with them down. I’m hoping that some carpeting on the tunnel and floors will be effective in absorbing that sound and keeping it from bouncing around.

When I got mine it was really noisy. Every time I hit a bump it sounded like the whole front end was going to rattle off. Found the jack under the front seat and removed it. Noise went away, no deadening required! But with no doors and a soft top it is pretty noisy running into town.

Autonomy_Lost said:

I used kilmat inside the doghouse (between the fiberglass and the heat shield) and 1" thick horse stall mats on the tunnel and floor.

While you can do much, much more than this, it still made a pretty good difference. You can hold a conversation without needing the intercom system, and the noise is not uncomortable for long trips.

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I've read good things about about Kilmat, may be a good product to play with...

Autonomy_Lost said:

I used kilmat inside the doghouse (between the fiberglass and the heat shield) and 1" thick horse stall mats on the tunnel and floor.

While you can do much, much more than this, it still made a pretty good difference. You can hold a conversation without needing the intercom system, and the noise is not uncomortable for long trips.

Click to expand...

Horse stall matts are also an avenue I've considered, the local TSC (Tractor Supply Company Stores) have a decent selection for a good price.

thoner7 said:

I’ve been trying to soundproof mine. Most of the noise comes from the engine, obviously.

I built a second doghouse, similar to the console in the Hummers. I’m not done but I did test it. I put pieces of scrap foam cushions inside. That has seemingly been the most effective thing I’ve done. If you have a non turbo truck, buying a turbo dog house cover and then filling all that space with some kind of sound blocker material could be a great option.

I used siless liner products and put down some of that. Similar to killmat. In a humvee, the tunnel is plenty solid and doesn’t need it. A few pieces on the floor is enough to be effective.

Click to expand...

Siless? First to hear of it, looks pretty good online. Soooooo many choices...

Thanks all for your input. Hopefully we get more experiences posted here.

I too bought a horse stall mat and cut it just for the rear cargo area. That stuff is indestructible. But as far as using it on the pass area, those are almost impossible to cut. I smoked a circular saw trying to make just one cut for that rear mat, and a second saw was ready to go. How do you possibly cut them?

FlameRed said:

I too bought a horse stall mat and cut it just for the rear cargo area. That stuff is indestructible. But as far as using it on the pass area, those are almost impossible to cut. I smoked a circular saw trying to make just one cut for that rear mat, and a second saw was ready to go. How do you possibly cut them?

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Mark your line with marker. Bend the mat away from the line. Cut the line with a sharp utility knife. It will go through in a couple of passes.

It helps to put some grease on the blade.

I have also seen rolls of softer more flexible rubber at Lowe’s or Home Depot. 30-36” wide. It’s in the carpet runner section and the same dimension, like the stuff you’d install on stairs or in a hallway.

could be a good option for floor mats. I haven’t used it.

Has anyone ever considered using seadek boat foam for flooring? I think it would be a good option to help with sound and it is pretty durable and looks cool as well. I have never used it so don’t really know.


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I did it doing a multi-layered process. It's not cheap by the time you add it all up, but it's a very notable difference, - you can actually have a conversation with each other across the slantback. Do it right by cleaning, scrubbing and vacuuming all of the dirt and sand out of the truck and use a roller to make sure that the layers adhere well.

- The first layer was the 80mil (2mm) Siless peel and stick insulation.
- The second layer was 157mil (4mm) Siless peel and stick insulation, over the top of the first layer.
- The 3rd layer was the DB Engineering Accoustical Floormat - it looks just like the factory insulation.

A couple of key points to focus on:

- Make sure you insulate behind the doghouse with the 2mil and 4mil layers.
- In the area of the gas pedal, be very careful to not go too thick as the space between the accelerator pedal and the wall is pretty minimal. You don't want to end up in a position where your accelerator gets stuck.

Foxclub83 said:

Has anyone ever considered using seadek boat foam for flooring? I think it would be a good option to help with sound and it is pretty durable and looks cool as well. I have never used it so don’t really know.


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Seadek is for "flat smooth surfaces", that would lead me to believe it may not work well on contoured surfaces.

Foxclub83 said:

Has anyone ever considered using seadek boat foam for flooring? I think it would be a good option to help with sound and it is pretty durable and looks cool as well. I have never used it so don’t really know.


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Interesting idea with the boat foam flooring. It’s about half the price of the automotive carpet I was considering.

carpet is a fairly good sound absorber. Anyone want to wager a guess as to how the boat foam would perform? I’m just laying it on the tunnel

thoner7 said:

Interesting idea with the boat foam flooring. It’s about half the price of the automotive carpet I was considering.

carpet is a fairly good sound absorber. Anyone want to wager a guess as to how the boat foam would perform? I’m just laying it on the tunnel

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I think it would be a good option for the tunnel and floorboards. I have also considered using it to make door panels. Still have to do something on the doghouse and tunnel sides that will hug contours so it may not be a good option.

All I know is my truck doesn't have insulation in it, just bed liner sprayed in the entire tub. It's pretty damn loud, especially above 55mph.

How do these various solutions affect the draining slots on the floors? I'd hate to have water pooling.

Mainsail said:

How do these various solutions affect the draining slots on the floors? I'd hate to have water pooling.

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A friend had the Kilmat equivalent and boat carpeting installed on the passenger floors and indeed water pooled and resulted in disgusting mold so he removed it just on the passenger floor panels. It was not fun to remove but that is what he did on the floors.

I considered making holes where the dains are located. When I installed mine I did not listen to him as everything ended up being so thick I did not think it would drain properly. I installed Kilmat and boat carpeting sealing up the drains on the floors but I also installed generic rubber mats on top which catches the water coming through the windshield and crowl. Any water that pools evaporates in the Florida Inferno very quickly so I have not seen a mold problem yet myself. Perhaps my roof seals better or perhaps the truck cover I have helps keep out rain better?

So yes, this is a concern.

Mainsail said:

How do these various solutions affect the draining slots on the floors? I'd hate to have water pooling.

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.

The factory installed insulation I have in my M1123 has a "channel" up front to where the water could drain over into the drain vent out the floor.

Valid concern if one did seal the floor completely. Maybe easy enough to cut through the material with a long box cutter blade from underneath after the fact?

Mainsail said:

How do these various solutions affect the draining slots on the floors? I'd hate to have water pooling.

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No issues with the horse stall mats because its not that tight of a fit, the water finds its way around it and out the drain holes.

I’ve been cutting holes to allow water to drain through. Not always in the exact spot of the tubs drain hole, but in a corner where the water will find its way out into one of those holes. That way it’s not a direct route for sound? Who knows if that helps