Soundproofing/deadening a vehicle


Lasherž

CarAudio.com Veteran
Apr 27, 2020
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I'm curious what class of products are most regularly used together for achieving both soundproofing (exterior noise like road noise) and deadening (interior noise like high octave resonances). In a car, what contributes the most to a rigid sounding interior? My car isn't a luxury brand (Accord), so I only have single pane windows and don't have completely filled out wheel wells, so I'm not expecting perfection, just more substantial blocking for door speakers and general resonance attenuation mostly from the sound system.

I currently have Decidamp SP80 and I know this alone won't achieve the desired effects. What product(s) would you add to go with it? Decidamp properties are listed here: https://www.pyroteknc.com/products/decidamp/decidamp-sp80/ along with a whole host of technical breakdowns. It's a bit above my pay grade to understand everything about it, but it attenuates tinging of rain very well and obviously has a butyl-like structure yet doesn't ever recommend a constrained layer like some of their other products.

Also, I should ask what order you would recommend placing these products.
 
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Lasherž

Lasherž

CarAudio.com Veteran
Apr 27, 2020
521
92
United States
I suggest starting here..

www.resonixsoundsolutions.com/reference-information

We sell the best CLD and CCF in the car audio market, but no noise barrier. For that, we just recommend getting virgin MLV or lead sheet from amazon. Any questions after reading that article feel free to ask.
Awesome that's exactly what I was looking for, much appreciated. So from what I gathered on that page the only thing that wasn't clear is for an outer panel surface like the sheetmetal reverse side of a door, they recommend installing MLV to cut down on noise, but also recommend an air-gap. Should that air-gap consist of a layer of dampener like closed cell foam, CLD, or the MLV then those things?

I guess what I'm asking is behind the mid driver in the door and against the outer sheet metal, what should the order be for each of those 3 categories?
 

SkizeR

Member
May 28, 2011
139
30
New York
Awesome that's exactly what I was looking for, much appreciated. So from what I gathered on that page the only thing that wasn't clear is for an outer panel surface like the sheetmetal reverse side of a door, they recommend installing MLV to cut down on noise, but also recommend an air-gap. Should that air-gap consist of a layer of dampener like closed cell foam, CLD, or the MLV then those things?

I guess what I'm asking is behind the mid driver in the door and against the outer sheet metal, what should the order be for each of those 3 categories?
MLV and CCF dont go on the outer skin. They go on the inner skin (the part of the door that the door panel attaches to. It would be CLD, CCF, then MLV and ideally another layer of CCF. Noise barriers need an air gap between them and the substrate to work properly. CCF acts as the decoupler/air gap. That said, a full soundproofing job is a TON of work. I hope you know what you're getting yourself into.
 
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Lasherž

Lasherž

CarAudio.com Veteran
Apr 27, 2020
521
92
United States
MLV and CCF dont go on the outer skin. They go on the inner skin (the part of the door that the door panel attaches to. It would be CLD, CCF, then MLV and ideally another layer of CCF. Noise barriers need an air gap between them and the substrate to work properly. CCF acts as the decoupler/air gap. That said, a full soundproofing job is a TON of work. I hope you know what you're getting yourself into.
Gotcha, I appreciate it. So the only thing that would touch the outer skin is the butyl rope between things like the support bars and the outer skin? The image on the site seemed to show a full MLV coating on the reverse side of the painted door exterior but I see now that it's actually ABS plastic it just looked like the holes were still there lol.
That said, a full soundproofing job is a TON of work. I hope you know what you're getting yourself into.
For sure, I'm debating what to do with my car at the moment, between upgrading the head unit (a real PITA to maintain the old features and requires permanent albeit hidden alterations to the car), sound deadening it, and giving up a lot of trunk space to add another subwoofer. Due to the covid-19 stuff I've got a lot more time than normal and a lot less money than normal, so leaning towards soundproofing. I know once I get started it's going to be a major cripple on the usefulness of the car until it's done unless I want to get very good at reassembling the car.
 

SkizeR

Member
May 28, 2011
139
30
New York
Gotcha, I appreciate it. So the only thing that would touch the outer skin is the butyl rope between things like the support bars and the outer skin? The image on the site seemed to show a full MLV coating on the reverse side of the painted door exterior but I see now that it's actually ABS plastic it just looked like the holes were still there lol.

For sure, I'm debating what to do with my car at the moment, between upgrading the head unit (a real PITA to maintain the old features and requires permanent albeit hidden alterations to the car), sound deadening it, and giving up a lot of trunk space to add another subwoofer. Due to the covid-19 stuff I've got a lot more time than normal and a lot less money than normal, so leaning towards soundproofing. I know once I get started it's going to be a major cripple on the usefulness of the car until it's done unless I want to get very good at reassembling the car.
constrained layer damper would be on the outer skin too. Did the guide not go over this well enough? honest question
 
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Lasherž

Lasherž

CarAudio.com Veteran
Apr 27, 2020
521
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United States
constrained layer damper would be on the outer skin too. Did the guide not go over this well enough? honest question
In hindsight after rereading the whole page with that in mind I think it's clear enough. It does take more than one read, but I think the reason is that terms are used interchangeably when going from general rules (CLD) to build-log (ResoNix Squares). As a first time reader I hadn't yet understood ResoNix Squares to mean part of the CLD layer. The doors are a good tool since they're first in the mix for most people, but maybe with the cavity they add it would be good to do a little section on a more simple structure like the floor.

Rereading a 3rd time the section with the door I think another contributing factor is that MLV isn't mentioned at all in a hands-on context, so with the door as the example it makes me wonder where that would come into the mix if we're covering the door in only the other 2 and basically sealing it off from any MLV usage unless we undo some of the work when we go back to do that step. I understand now from your posts here that it would go between the two CCF layers, but I don't think that example contained that. The example is also listed right after talking about the importance of soundproofing everything if you're going to soundproof it, meaning the doors would be involved in that part for a fully involved effort. I think the guide could address that better, but I could have also taken more time to try and understand. The lack of MLV example is the only point that I think would be a benefit to the article that isn't just me not knowing what each product is for the duration of the article after brief introductions.

Not for nothing you pretty much cover it in the last paragraph, "This just about wraps it up for our method of getting the most out of sound treating your doors. The only other thing you could add is a noise barrier, but we don’t see a point in doing that unless you are soundproofing your entire vehicle. Unfortunately, we do not sell a noise barrier so we do not see a need to include it in our guide. Long story short, it would go between your door car and the decoupling layer. Ideally, it would have a decoupling layer on both sides."

Fair enough, I can't really knock the guide on that since you don't sell it. I guess it wouldn't really matter which surface the MLV was attached to, but that would be good to specify how you would recommend it as a quick side-note. For example, would it be more beneficial to put it on the panel or the rigid metal door frame? CCF doesn't seem like the easiest thing to get good adhesion on for panels of vinyl.

From what you said above combined with the website it would be CLD on the outer skin with nothing else, then patching the holes, then applying to the metal framework the CCF layer, then MLV, then on the panel that connects to it more CLD under CCF along with butyl rope patchwork on the connecting clips to stymie their vibration?
 
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SkizeR

Member
May 28, 2011
139
30
New York
From what you said above combined with the website it would be CLD on the outer skin with nothing else, then patching the holes, then applying to the metal framework the CCF layer, then MLV, then on the panel that connects to it more CLD under CCF along with butyl rope patchwork on the connecting clips to stymie their vibration?
CLD and butyl rope on outer skin, CLD and CCF on inner skin. CLD on door card. Spot treat door car with ccf and/or butyl rope. Add noise barrier at your discretion.
 
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Lasherž

Lasherž

CarAudio.com Veteran
Apr 27, 2020
521
92
United States
CLD and butyl rope on outer skin, CLD and CCF on inner skin. CLD on door card. Spot treat door car with ccf and/or butyl rope. Add noise barrier at your discretion.
I've now purchased what I'll need to do the front doors:
CLD, MLV, CCF, Butyl rope, and polycarbonate to use as a patch for the 2 large holes in my inner door structure.

My only question now after rereading your website's guide is when I put down the plastic patches, what should I use to go between the plastic and the metal or does it matter? I was thinking of doing butyl rope but wasn't sure if it would have enough sticking power with a 200w driver pushing behind it (not that it'll be a perfect seal, but still).

I'll also add that I'll be heating the polycarbonate to fit tightly against the metal all the way around the hole, so presumably a normal plastic/metal adhesive or maybe you could recommend one with a more gummy consistency like what originally came on the car to seal out water.
 
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SkizeR

Member
May 28, 2011
139
30
New York
I've now purchased what I'll need to do the front doors:
CLD, MLV, CCF, Butyl rope, and polycarbonate to use as a patch for the 2 large holes in my inner door structure.

My only question now after rereading your website's guide is when I put down the plastic patches, what should I use to go between the plastic and the metal or does it matter? I was thinking of doing butyl rope but wasn't sure if it would have enough sticking power with a 200w driver pushing behind it (not that it'll be a perfect seal, but still).

I'll also add that I'll be heating the polycarbonate to fit tightly against the metal all the way around the hole, so presumably a normal plastic/metal adhesive or maybe you could recommend one with a more gummy consistency like what originally came on the car to seal out water.
Ideally you should be securing it with mechanical fasteners, and seal it with CCF
 
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