Sound deadening "upgrade"?

[TeeJayHoward]

My horse-hair whatever that's protecting my poor, sensitive ears from the clanking and clanging happening behind me on a drive is... Well, old. It's in pretty good shape, and I guess it does it's job, but I need to track down a leak and I've a feeling that I'm going to end up removing the cigar-smoke-infused old stuff in the process. Before I do, I need to make sure I've got a replacement laying around, ready for the install.

Are modern sound deadening materials any upgrade for the old stuff, or has the field not really advanced all that far? I've got some dynamat laying around. (Sadly, no CCF or MLV, just the sticky stuff.) If I were to replace the in-cabin-firewall/deck thick mat-thing with that, would I notice an increase in volume?

[fanaudical]

I went through this several years ago and used a Dynamat clone. I hadn't driven the car previous so have nothing to compare it to. After the fact I ran across this stuff (and figured that this is what I would use if I ever did it again):

https://lizardskin.com/

[PeteKz]

I pulled out the OE stuff from my 1973 car to clean out the rust in the seat buckets and rear shelf. the jute layer under the rubber layer was pretty deteriorated, so I put Dynamat back in, then the usual rear upholstery. I'd say the Dynamat is pretty good at deadening sound, but the OE stuff was a little better, however the OE stuff weighs a lot more.

Net-net, I'm happy to have replaced the OE sound deadening with the Dynamat. If there's more noise coming from the business end, it's only when I'm hard on the throttle and high RPM. No discernible difference at moderate throttle or highway cruising speeds.

[Packin4]

Are modern sound deadening materials any upgrade for the old stuff, or has the field not really advanced all that far? I've got some dynamat laying around. (Sadly, no CCF or MLV, just the sticky stuff.) If I were to replace the in-cabin-firewall/deck thick mat-thing with that, would I notice an increase in volume?[/QUOTE]

Sound deadening and absorption materials have definitely improved. You can go here and figure out what your needs are or call Nick for advice. Audio guys have proven this is the best stuff going. I have no affiliation....

https://resonixsoundsolutions.com

[thetorch]

If you want to do it right, you want a combination of sound/vibration dampening, sound blocking and sound absorption. Good explainer here.

https://www.secondskinaudio.com/sound-deadening/car-soundproofing/

I used their Luxury Liner Pro. Not light, but it works very well. Curves take some effort to make seamless by trimming the mvl edges. It's about the same thickness as the horsehair and tar that was in my car originally. Maybe a little thicker.

Do not make the common mistake of covering huge areas with 100% sound dampener (like Dynomat or Damplifier Pro). You only need to do larger flat areas that can vibrate, and 25%-60% coverage is plenty. People cover their entire interior with this stuff, and it just adds unnecessary weight.

[dannobee]

Originally Posted by thetorch

Do not make the common mistake of covering huge areas with 100% sound dampener (like Dynomat or Damplifier Pro). You only need to do larger flat areas that can vibrate, and 25%-60% coverage is plenty. People cover their entire interior with this stuff, and it just adds unnecessary weight.

^^^THIS^^^

In all of my years of ripping and tearing apart interiors in high end cars for various repairs behind said panels, I've seen the progression of sound deadening. Modern cars more often than not use a small strip of heavy sound deadening in the middle of larger panels and strategically located smaller strips in certain areas, then combine that with a thinsulate type material on the backside of interior panels, and even then, the thinsulate rarely covers the whole inside of the panel, only strips or patches.

Short of breaking out the engineering crew, test track, dB meter and spectrum analyzer, I'd follow what most of the factories use.

[SAMEF80]

As long as it's worth it.

[Dpmulvan]

Originally Posted by SAMEF80

As long as it's worth it.

Yeh right, I guess you either buy it and try it or take someone else’s word and nothing is easily reversed once it’s done and seats are back in. There really is no simple, light, one and done inexpensive material out there.

[ZeroHecksGiven]

A guy I follow in the "off road" world did a guide on adding sound deadening to his Tacoma. He talks a little about a few options there, I would assume that would carry over into this world as well, but maybe not. At least it would add a few products to look into:
https://adventuretaco.com/guide/sound-deadening-a-1st-gen-tacoma-materials-and-prep/

[jac1976]

Maybe Jamie will drop in with his experience with LizardSkin. In my limited experience and research, mass is the one of the major irrefutable solutions and those concerned with its negative effects on vehicle dynamics and performance must find a workaround. Most workarounds, whether due to R&D, material costs, implementation, etc. tend to cost more to meet the desired performance.

[r_towle]

It seems that sound deadening it all about variety.
When something like dynomat blocks some vibration, and certain frequencies, when used with other materials you get a better blocking effect.

So, Rubber, ceramic spray on, wool, all combined does the best job.

If you go look at the materials used in modern S class Mercedes, you will see all three.

The super luxury use something like Lizard Skin (a spray on ceramic undercoating with little ceramic balls to help reduce certain frequencies)
then rubber, dynomat etc
Then wool backed glued to either more rubber or carpet underlayment...depends on the car.

The cheaper way is rubber roofing from Home Depot, the self stick stuff.

Rich

[PeteKz]

Originally Posted by dannobee

^^^THIS^^^

In all of my years of ripping and tearing apart interiors in high end cars for various repairs behind said panels, I've seen the progression of sound deadening. Modern cars more often than not use a small strip of heavy sound deadening in the middle of larger panels and strategically located smaller strips in certain areas, then combine that with a thinsulate type material on the backside of interior panels, and even then, the thinsulate rarely covers the whole inside of the panel, only strips or patches.

Short of breaking out the engineering crew, test track, dB meter and spectrum analyzer, I'd follow what most of the factories use.

I hear ya, but I think that works in modern cars to prevent large panels from vibrating and transmitting sound because the car makers have paid a lot of attention to eliminating noise at the sources now. "NVH" is now a critical part of testing and development in a car, whereas when many of our cars were designed, it wasn't.

I agree that you don't need to cover every square inch of most parts of a 911, such as the inside door panels, frunk panels, footwells, etc. But for the rear seat and shelf, so much noise comes from the engine and transmission and wheel wells and transmits through the metal body parts that it "probably" helps to cover those parts completely. I will also note that Porsche covered that area completely too (and the floor), presumably for good reason. Whereas, you don't find much sound deadening in the rest of the car.

Of course, without rigorous testing, I don't know for sure, but now I have to rationalize why I did it, right?

[Jukan89]

By adding more sound damping material, you can usually reduce those sound levels by another 4 to 5 decibels. In doing so, you'll be able to hear your music more and even carry on a normal conversation in the car.

[jac1976]

Originally Posted by Jukan89

ResoNix Sound Damping Solutions is a company with a specialty in high-end car audio and automotive sound treatment that offers top quality products and services that provide superior performance in their respective categories. No gimmicks, no baseless claims, no nonsense. Constrained layer dampers, sound absorbers, decouplers, noise barriers, and car audio DSP tuning and consultation services are part of our line-up with a focus on data-backed, solutions-based products developed by professional enthusiasts, for enthusiasts.

Wow. It’s almost as if you work for them.

[gtc]

I bought the lizard skin kit and sprayed it on the floorpans and on the rear deck of my targa. I sprayed it on to their suggested thickness, i think 2-3 coats in most places.
I removed the factory asphalt from the floorpans, as well as the heavy sound pad under the rear deck. I also removed the carpet from the back seat area and the longitudinals.
I had removed the engine compartment sound pad years ago, so that was not part of my comparison.
I would definitely say that the noise level is higher with the lizard skin. In retrospect, i would need several more coats to reach the same mass as the asphalt mats i took out. I will say that it is nice and durable (I topcoated with some satin black 2k epoxy). I should have sprayed their heat coating, as the heat transfer to the passenger compartment is now quite a bit higher.
Aside from all the prep work to remove the old adhesive, the application was very easy, and it is nice being able to coat any curved surfaces.
Doing it again, i would probably apply some dynamat to flat panels, then spray over the top of everything with both lizard skin coatings.

Originally Posted by fanaudical

I went through this several years ago and used a Dynamat clone. I hadn't driven the car previous so have nothing to compare it to. After the fact I ran across this stuff (and figured that this is what I would use if I ever did it again):

https://lizardskin.com/

[fanaudical]

Good info, GTC - thanks.

[pmax]

Originally Posted by PeteKz

I pulled out the OE stuff from my 1973 car to clean out the rust in the seat buckets and rear shelf.

Yeah, the OE stuff, what a mess.

I'll take a few more decibels over that again.