School me on sound deadener

mudgudgeon

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Much appreciated, and thank you for the detailed reply. I don't know anything about this stuff, so forgive me for asking this. You said that your second layer as an eva foam with foil on one side - does it matter which side has the foil? Is the foil always opposite the sticky side? Thanks again.

Dynamat has a sticky side, with foil on the opposite side.
I did the same with the eva foam product I used.
So the foam absorbs heat and sound, and foil is the final barrier.
The thing that insulates is the trapped air pockets within the foam.
Same with thinsulste, it's the trapped air within the fabric that insulates.
 
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Thanks for all the suggestions and info. I am not very concerned about most road noises or trying to regulate temperatures. I just want to mellow out the exhaust note for longer interstate drives, especially with passengers who don't want to listen to a cranked stereo all day.

I already have the rear quarter panels torn apart so I think I am going to order this hushmat and just hit the rear quarter panels.

This is the hushmat I am thinking of ordering.

https://hushmat.com/products/under-carpet-floor-kit-1-2in-silencer-megabond-thermal-insulating-and-sound-absorbing-self-adhesive-foam-2-sheets-23inx36in-ea-11-5-sq-f

What do you guys think? Fyi my exhaust tailpipe currently ends right under the passenger rear quarter panel.


I will try to record the sound levels before and after the hushmat if I go this route. If my exhaust is still too loud than I will take it to an exhaust shop and see if I can get the tailpipe extended beyond the body.

Thanks again
While a full, interior-out sound deadening project sounds like fun, I think it may be a lot of effort and cost for very little help with your problem. If the exhaust drones at freeway cruising RPM, I'd start with the extension of the exhaust pipe, but you really may have to consider a more OEM style muffler.
 
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Thinsulate, did you first add the Butyl mat to the quarter panels and then glue on the Thinsulate? And I can only find SM600L on Amazon. Can you send a link to the stuff you used?
Yes, I put the Noico down on the quarter panels first.

And I was wrong, I used SM400L! No idea why I settled on that in particular. I bought from eBay seller impactproducts. They're located in Hood River, Oregon, and specialize in "van life" products.

I think I used 3M Super 90 spray adhesive to glue the SM400L to the quarter panel. I mostly did a light coat on the upper part down to the point where the panel is vertical. Below that, I think I let it hang free. I also put a few layers over the wheel wells, including the portion that extends past where the plastic trim panels would be. This isn't really an option for stock setups, but I've got drawers that cover the whole area.
 

Francis K

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So what you guys are saying is that in order to do this correctly it’s a 3 part procsss…..deadened, foam and then MLV. Do I have that correct? What a mess….
 
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So what you guys are saying is that in order to do this correctly it’s a 3 part procsss…..deadened, foam and then MLV. Do I have that correct? What a mess….
Depends on your goals, problems, and level of interest. Also, it doesn't have to be foam, it just has to be something that absorbs sound.
 

Francis K

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Depends on your goals, problems, and level of interest. Also, it doesn't have to be foam, it just has to be something that absorbs sound.


I don’t think she’s especially loud as is and insulation from heat isn’t so much an issue being in Michigan. I picked up new front and rear seats so while they were out I figured I would also take the carpet out to clean it and “while I’m in there” put some extra deadening down on top of the factory crap then do the doors as well eventually, not sure about the headliner. So dynamat/hushmat or whatever is really just the first step, would be nice if there was simply an all in one product!
 
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So dynamat/hushmat or whatever is really just the first step, would be nice if
IMO, people are overly obsessed with mass-loading the floor of the 80-series. It's already got substantial amounts of mass-loading from the factory.

A better quality underlayment and layer of mass-loaded vinyl under the carpet is more important, again, in my opinion.
 

Francis K

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IMO, people are overly obsessed with mass-loading the floor of the 80-series. It's already got substantial amounts of mass-loading from the factory.

A better quality underlayment and layer of mass-loaded vinyl under the carpet is more important, again, in my opinion.


What would you suggest for a basic cost effective setup?
 

Somebodyelse5

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IMO, people are overly obsessed with mass-loading the floor of the 80-series. It's already got substantial amounts of mass-loading from the factory.

A better quality underlayment and layer of mass-loaded vinyl under the carpet is more important, again, in my opinion.

So, you say the floor has enough mass... and then you say to add more mass?
 

Somebodyelse5

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No. Spend less time on snark and more time on actually understanding the words in front of you.
IMO, people are overly obsessed with mass-loading the floor of the 80-series. It's already got substantial amounts of mass-loading from the factory.

A better quality underlayment and layer of mass-loaded vinyl under the carpet is more important, again, in my opinion.

So, "under the carpet" is not the same as "the floor" ?

I don't understand. help us peasants beneath you understand, all mighty wise oregonian.
 
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The spray boommatt in the door also helps - and be sure to do the firewall.... it's a pain but very worthwhile. Also I did a heavy coat of raptorliner in my wheelwheels and even my wife noticed the difference when I had the rug out and did it in between two trips to the store....The headliner take commitment but I did it on my 40th and it really cut the vibration/ boom on road transitions etc...

it 's all about use case and what it's intended for and how much time/effort you can spare..... don't try to write a check for this kind of things.... my buddy got a HUGE bill from a shop he asked to do it while upgrading his new JKUR's stereo..... it was as much as a new high end system !
 
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So, "under the carpet" is not the same as "the floor" ?

I don't understand. help us peasants beneath you understand, all mighty wise oregonian.

Nice. Double down on the snottiness.

I've already written a long summary of the complex topic of noise reduction *in this thread*. Your inability to pay attention isn't my problem, and I'm not taking time out of my day to cater to a snotty, snarky twit.
 

Somebodyelse5

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Nice. Double down on the snottiness.

I've already written a long summary of the complex topic of noise reduction *in this thread*. Your inability to pay attention isn't my problem, and I'm not taking time out of my day to cater to a snotty, snarky twit.
BE3E4DA2-D037-45BC-8D62-CDDFD9051D93.jpeg
 

Francis K

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The spray boommatt in the door also helps - and be sure to do the firewall.... it's a pain but very worthwhile. Also I did a heavy coat of raptorliner in my wheelwheels and even my wife noticed the difference when I had the rug out and did it in between two trips to the store....The headliner take commitment but I did it on my 40th and it really cut the vibration/ boom on road transitions etc...

it 's all about use case and what it's intended for and how much time/effort you can spare..... don't try to write a check for this kind of things.... my buddy got a HUGE bill from a shop he asked to do it while upgrading his new JKUR's stereo..... it was as much as a new high end system !


You sprayed the doors instead of putting mat? That sure sounds a lot easier, it didn’t stink up the interior? Hell i wish i could just spray under the carpet too….

Why didn’t you also use the boom mat on your wheel wells instead of the raptor liner?
 

alia176

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This was my first idea but the rig had a complete new exhaust installed by the previous owner. Full stainless to the cat including the headers. I just can't justify spending the money to remove a perfectly good new muffler when there is nothing wrong with it other than the noise.

You have a pretty big investment in your exhaust system and if you are still not happy with the sound, I might have a possible solution for you.

I too have an issue with the droning of my exhaust system that I built from scratch using mandrel bent tubing and such. A super quiet muffler means a lot of back pressure, which is something I didn't want so it is a huge trade-off. However, I will be designing a Helmholtz resonator for the exhaust in order to cancel out that specific frequency of droning sound and this will not introduce any back pressure to the system.
 
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However, I will be designing a Helmholtz resonator for the exhaust in order to cancel out that specific frequency of droning sound and this will not introduce any back pressure to the system.

Let me know how it goes once your done. I am very curious to see what you come up with.
 

alia176

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I do have a question for my particular 80 which has a rooftop tent, rear cargo drawers, middle row platform that supports a fridge and other stuff. Given that I have so much stuff on the floor and on top of the roof, would I still benefit from putting these sound absorbing mat?

I have installed sound absorbing mat on all the side panels of my vehicle using the 25% rule but left the floor and the ceiling untouched because I didn't think I was receiving that much nvh given that I run only aggressive at tires.

I also have a wind fairing in front of my rtt so I don't hear a whole bunch of wind noise through the sunroof but rather go a fair amount of wind leaking through the front two door frames. I have replaced both seals on each door and body but still have wind noise. Had a local body shop bend the window frames inward a little bit but that really didn't help a whole bunch. Other than the wind noise, my 80 is fairly quiet but I'm obviously very biased!

Thanks for your input.
 
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Given that I have so much stuff on the floor and on top of the roof, would I still bene
DynaMat/Noico on the rear quarter panel and door skins might help a bit. Some sound absorbent material in the various crevices (e.g. behind the kick panels) with some MLV barrier over the top. But if you're not particularly bothered by anything currently, then there really isn't a problem to be solved.

For wind noise, you can try taping over seams to narrow down the actual source of the noise. I like to use blue painter's tape because it doesn't leave any residue.

I'll be applying deadening to my roof, because it sounds like a tin shed in Oregon rain, but I haven't figured out a solution to wind noise. It's not bad, but it's going to be the next biggest nuisance.

For door seals, I think some people have sliced them open and fed surgical tubing (I think?) into them for a better seal. I think that was more of a cheap hack for aged seals than an improvement for new ones.

A long time ago, a buddy dropped something like $10k (in 90s dollars) to have a pro-audio shop completely deck out his Civic. They used aftermarket bulb seals on the doors. That noticably cut down on road and wind noise coming through the doors. It was still a Civic, though...
 

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