Sound Deadening Butyl Mat Layer Covering

[snowboardwcu]

lots of threads on sound deadening, i know the process and the layers etc etc. butyl mat for vibration dampening, Closed cell foam for separating butyl from mass loaded vinyl, the the MLV.

what i cannot figure out from the threads is why anyone (really from i see, everyone) is completely covering every square inch of the truck in the butyl mat layer? most instructions talk about 25% coverage to reduce rattle/vibration.

personally i would presume that covering more than 25% comes with diminishing returns. for the expense that is the butyl mat, i really want to know if anyone has evidence that there's a huge dB difference between 25% and 100% coverage?

i'm also presuming, as i've read, the MLV layer is what dampens most of the sound. so i would anticipate approaching 100% coverage with MLV on top of "problem areas" coverage of the butyl mat/CCF coverage.

what do i have wrong here?

 

[ads2539]

I wonder the same thing. I didn’t do anything close to 100% with the butyl mat layer in my 4Runner.

 

[snowboardwcu]

I wonder the same thing. I didn’t do anything close to 100% with the butyl mat layer in my 4Runner.

haha thank you! did you see (hear) good results? what was your approach?

 

[Monty87ls]

In my research I have found to achieve vibration reduction and noise reduction full coverage isn't needed and for most people just covering the smaller area is fine. When I do mine I will do at least 75% coverage under carpet, doors maybe the firewall. If I really feel like making it a really fun project I will take the headliner down and do under the hood. Dynamite I believe make a product for bother those applications

 

[Monty87ls]

25% isn't enough though. At least 50% would be the min.

 

[ads2539]

haha thank you! did you see (hear) good results? what was your approach?

Thanks to covid19, I haven’t been driving my 4Runner much lately (only ~600-700 miles of mostly local driving so far in 2020!), and I have done the sound deadening/insulation during this time. I did 2 steps, Noico butyl sound deadening mat and then Noico 170 mil foam sound insulation. I have done all four doors, the hatch, the roof and under the hood so far. I still plan to do the floor/firewall and the cargo area, and maybe the front wheel wells. It’s quieter, but I can’t really quantify how much quieter. I’ve already forgotten how it used to sound.

I’ll have a better idea how it all worked after I start driving more and/or take a road trip or drive on the interstate.

Sorry I can’t give better feedback!

 

[snowboardwcu]

25% isn't enough though. At least 50% would be the min.

based on what?

if manufacturer reccommends 25% and that dissipates (fake number) 75% of vibrational sound then does 50% coverage dissipate 85% and so on?

i dont doubt there's additional sound deadening on higher coverages but 100% coverage would costs ~$350 so if i'm getting 10% gain for $250 more dollars, i personally wouldn't bother.

 

[Monty87ls]

based on what?

if manufacturer reccommends 25% and that dissipates (fake number) 75% of vibrational sound then does 50% coverage dissipate 85% and so on?

i dont doubt there's additional sound deadening on higher coverages but 100% coverage would costs ~$350 so if i'm getting 10% gain for $250 more dollars, i personally wouldn't bother.

Just on my research and hearing differences in friends cars, Dynamat for example says for a basic change in noise and vibration reduction use 30% but for a extreme difference to be heard cover 100% and that will cause some significant db drops.

Now I will say when it comes to my own car when I do it i will be using a 3 in1 product made by Soundskins. 3 layers that all help reduce noise and makes it one install unless I choose to do the roof and hood also from Dynamat.

Someone on another thread recommended another brand... I forget the name but I'm gonna look into that as well. For me if im taking the time to rip apart the interior I'm gonna cover as most as I can while I'm in there. At minimum I would do 50%

 

[Jbuckets]

any recommendations on thickness?