Sound Deadening Project

jtpedersen

Caught the Bug
Decided it was time to try doing some sound deadening in Stitch.

If you ever remove the carpet from your JK, what you find is near-zero sound deadening material. There's a few small pieces, wafer-thin, where your feet go front and rear (JKU), and on the rear deck. You can see some under the shop lamp. You can hardly tell it has any effect. There's also a bit of battening adhered to the backside of the carpet up in the front foot well, that's about it. Worst thing about the battening (sort of a poly fill type material) is it never dries out and just acts like a moisture sponge.

Major areas like the rear wheel wells, like most of the tub, are nothing more than sheet metal. For such a huge noise-generating region, you'd think they'd have done 'something' to help reduce noise there.
Gutted-R.jpg

Started the project by pulling the doors, removing the seats, and otherwise gutting the interior. As part of the process I unfastened the wire harness so it could float free when time came to put matting underneath it. Starting Sunday around 1p, I was surprised to see it took me rest of the day.

The next part of the process was vacuuming, cleaning, and wiping down with denatured alcohol. Wanted to ensure the matting would adhere well. Along the way, have to say I was surprised by how many drain plugs there were. I figured there were 4, turns out more like 10. Go figure.

Some vids on this process go through the non-trivial effort of removing the center console. Biggest headache is getting the low/hi range knob off. I elected to skip that. You really only need to cover 25-50% of your surface area to get the sound deadening effect. I was shooting for 90%+, chose not to worry about the small area under that console.

The hardest piece you lay, is the first piece. Every piece after that, as you learn how to work the material, just gets easier. I chose to go with Dynamat. Most of these are 1-2mm aluminum backed by a butyl or butyl-mix product. A really good informational site to visit for specific info is https://soundproofliving.com/automotive-sound-deadening-materials/. I was going to go with one or two other similar, and much less expensive, products. Unfortunately Dynamat was the only one 'everyone' had in stock and could get to me in timely fashion.

Sound Deadened-R.jpg

Overall project took me about 20 hours, give or take. As you can see, I went for max effect. One of the byproducts of this material is it's ability to help reduce heat transfer, improving A/C effectiveness. That was the biggest reason for maximizing coverage beyond what was required for deadening alone.

About 4 hours project time was tied to cleaning. While I had seats and carpet out, I cleaned everything. Brought the shampooer out for the carpets, cleaned hard-to-get-clean spots on the seats, yaddi yaddi yaddi. Stitch hasn't been this clean since new.

So, the big question: Worth It?

A week's effort (couldn't get to it every night after work), about $330 in material, and test driving. My initial impression wasn't thrilling. Told my wife I wasn't sure it was worth all the time and effort. Next day, we had a hour trip somewhere, about 3/4 expressway. She told me the jeep seemed 'much quieter.' Guess that makes it worthwhile :).

Specific observations:
* Wind noise above the beltline on a really windy day (as in my test drive) masks overall effect. No surprise, not much we can do about that. It's a jeep.
* Cargo/rear wheel well area road noise is definitely reduced. Turning your head, you can definitely tell there's less noise from the wheels.
* Overall, it just seems quieter, 'down there.' All noise coming 'up' at you can be readily noted.
* Rough pavement noise is muted, gives impression of a 'more-refined' vehicle.

I don't want to overstate the impact. This won't turn your JK into a Rolls Royce gliding down the road. It's more in line with your vehicle having bad shocks. You don't really know/notice how much noise comes up at you from below, until after you've done this. Just like getting new shocks, it's still the same vehicle, just better now.

The next real question will be whether there's any impact in hot weather. We've got a trip south to Arkansas in 10 days. We'll find out.

Would I do it again? Hmmm mmmm mmm. Hmm, ask me in a few months :).
 

Torrin

Member
Please keep us updated. I am interested in how it does with the heat and AC. My white Jeep lives in Houston and softtop + AC is not quite enough sometimes in the summer.
 
20 hours seems like a lot of time but I admire your dedication. If it was me I would have just taken out all the carpet and laid down Dynamat where I could easily get to. Are you planning on doing behind the door trim?
 

SLO

Member
I did something similar a couple years ago. I did pull the center console and even did the tailgate. I used Liquid Lizard Skin...both the sound and heat control. In my opinion, it wasn’t worth it. I read a lot on sound control and found out that to make it work, you really need to add a decoupling layer. Also, dealing with the open cavities by the wheel wells. But, with all of that extra work I should have done, it won’t help the wind noise against a flat windshield and the tire noise from M/T’s. Also, my stupid light bar is louder than everything else combined.
 

jhelper

New member
Very interesting project, I was thinking of doing some myself, I got a new 4 door JL and already installed Boom Mat 9 piece roof set which works wonders, might buy some of there 12x12 strips and do under the carpets in the areas I can get to easily


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jtpedersen

Caught the Bug
20 hours seems like a lot of time but I admire your dedication. If it was me I would have just taken out all the carpet and laid down Dynamat where I could easily get to. Are you planning on doing behind the door trim?

About 4 hours of the overall project involved cleaning everything. There're a lot of things easily dealt with, when removed. About an hour or so was spent just cleaning the carpets. It did take longer than I'd expected (more like 8-12).

If I had skipped removing seats and doors, and just done the core floor areas, I'd have probably saved some time. But given how sticky the butyl is, and having seats (and the like) in the way, I'm glad I removed doors/seats. Completely eliminated that kind of interference.

Right now, I'm not planning to get into the doors. Perhaps when I'm sufficiently bored on a dark winter's weekend. Ah, even then, probably not :).

Please keep us updated. I am interested in how it does with the heat and AC. My white Jeep lives in Houston and softtop + AC is not quite enough sometimes in the summer.

Will let you know. I'm very curious as well. I think, combined with a ceiling liner, the overall effect would be noticeable.

LOL! I think there is some value in doing it. I feel like I get most of the noise from the windshield, doors, and directly below my feet. I might try this in just the doors, foot wells, and back.


Not trying to sell anyone. As I noted, I haven't decided yet for myself, whether it was worth it. It's an easy enough project, just time consuming. We've got a 1,500 mile road trip, heading south, a week away now. We'll see.

I will say, I'm glad I went with sheets rather than a roll. Easier to work with. A roll, I think I'd be trying to do the 'biggest' sections I could...and to be honest, given the workability of the product, smaller pieces (Dynanat's like 18"x32") are plenty big enough to manage.

The sound (benefit) is in the ear of the beholder<g>. Thought I'd share since not many have. Perhaps it'll be of use to folks who are curious.
:)
 

SLO

Member
For me personally, the thing that helped the most for quieting the cabin was installing headliners.
 

jtpedersen

Caught the Bug
For me personally, the thing that helped the most for quieting the cabin was installing headliners.

I'm thinking that's later-on, this season. Anyone have one they recommend? My brother got one for his, in Austin, in the heat it doesn't stay up. Sort of leary of a similar experience. Have also heard various comments...not enough to convince me one way the other. Thoughts?
 

SLO

Member
I'm thinking that's later-on, this season. Anyone have one they recommend? My brother got one for his, in Austin, in the heat it doesn't stay up. Sort of leary of a similar experience. Have also heard various comments...not enough to convince me one way the other. Thoughts?

I did the Hot Heads one. Not sure it’s any better than the others. They all have their pros and cons.
 
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