Sound Deadening 101: Know your products

jdc753

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I'm going to try and keep this simply but I know its going to get long and drawn out. I meant to write this up back when PSA first started but got sidetracked, but with all the questions lately I picked it up again. I hope to do another segment for installation tips/tricks and then maybe a 3rd installment for more advanced tips/tricks.



Basically I want to list off most all of the various products and manufacturers out there and try to educate people in how to best pick a product and understand why they are selecting it. I know things will change and I might be wrong on some things but hopefully this gets the basics to get people started.



First the education (boring part for most)



Ultimately you will have 3 layers to complete the acoustical treatments inside your vehicle. The first being the most common “Deadener” dampening mat, the second being a sound absorber or decoupler, and the final layer being a sound barrier.





Dampening Materials - Step 1



Now the first thing everyone thinks of is deadener, synonymous with the name brand product by Dynamat. The technical term for this product would be CLD, or Constrained Layer Damper.



What this consist of is generally a flexible layer either asphalt or butyl rubber based) bonded to a layer of aluminum foil.



cld_edge_t.jpg






When looking to select a damper the 2 key factors you want to look at are the Mass and the thickness of the foil. Essentially the higher mass means greater amount of flexible material which yields more energy dissipation (less vibrations) a thicker foil will be a stronger constraining layer, but too thick reduces the amount of flexibility for conforming to the shapes of a vehicles sheet metal. Some claim a thicker material and less coverage work, while others argue for 100% coverage sometimes 200% (double layers) coverage with a thinner cheaper damper.



Now applying the damper accomplishes half of the overall goal. The damper reduces any structural born noises (vibrations of the sheet metal.) This is usually caused from vehicle vibrations, bumps, wind/rain, speakers etc. Also the amount of panel resonance (the audible portion of the vibrations) varies depending on the panels overall stiffness. The thicker the panel, or the more bends in the panel the less chances for resonance.





Take a look at the sound you get when you’re washing your truck and you spray the bedside, or center of the door, vs the cab corner, or simply the center of the door vs the edge of the door. With the damper applied to the outer door skin (from the inside of the door) when the water hits the center of the door you will get pretty much the same result as if you were spraying the edge of the door, a nice dead sound of just the water and not a hollow echo from the door skin.





Noise Barriers - Step 2 and 3





Now to quell the rest of the road noise you need an "air barrier" that will actually filter and block out sound waves as they travel through the barrier. This is to combat the airborne noises such as exhaust, wind, tire hum, birds, small children, attack helicopters and light gun fire (as long as its not impacting your vehicle.)



This section can be broken down into 2 subsections for 2 different products. One is an actual barrier layer, MLV (mass loaded vinyl) and the other is an absorption filter layer, Closed Cell Foam. The MLV is the primary barrier component, while the closed cell foam is lesser effective across the frequency spectrum generally targeting higher frequencies, but often used together with MLV to decouple it further from your layer of damper.



Now not to add any confusion, BUT when you find yourself short of space, say on the floor for example, if is best to skip step 2 (CCF) and jump straight to the MLV, but if you have the room by all means build the layers up as thick as you can.





Closed Cell Foam – Step 2



overkill.jpg




For this filter or absorption layer what works best is a closed cell foam, it slows down the sound waves and also does not take on moisture like an open cell foam would. Again it is about energy dissipation, sound waves are a form of energy and as they travel through the closed cell foam they get slowed down and some of the sound energy gets dissipated into heat energy, think of it as putting on the brakes to the sound waves. The thicker the barrier the better as each millimeter of thickness will only slow the waves down by X amount.



Now closed cell foam is not nearly as effective at blocking sounds waves as MLV is but it is effective, mostly on higher frequency noises. Also it is very effective as a decoupler (same as the Butyl layer in the CLD) for MLV acting as a spring or cushion against any residual panel resonance.







Mass Loaded Vinyl (MLV) – Step 3



mlv.jpg




The mass loaded vinyl will act as a barrier to the sound waves, stopping them in their tracks better than any of the other products. Generally you will want an MLV that is around 1lb/ft^2 This will be your final layer between the outside work and your interior. It works along the same principals as the closed cell foam by slowing down the sound waves and converting the sound energy into heat energy.



The MLV works best when it is floated or decoupled off any surfaces but when lacking room the decoupling layer can be skipped. This way there is little to no chance of any residual resonances effecting the MLV layer.





Some worthwhile reading, http://www.sounddeadenershowdown.com/ and www.secondskinaudio.com





So there you have the basics of what materials you are looking to use. Now you don’t have to use all of them, or cover everything or spend more money than someone else, but understand what you are buying and add as budget allows, and now onto the materials available…





Materials and Manufacturer’s



CLD

Dynamat Xtreme by Dynamat – www.dynamat.com



Mass: 0.45lbs/ft^2

Overall Thickness: 1.7mm

Foil Thickness: 4mil

Price for bulk pack (36SF): $150, http://www.sonicelectronix.com/item_1726_Dynamat-Xtreme-36-Bulk-Pack-Entire-Car-10455.html



Price per square foot: $4.17 and mass per dollar per square foot – 0.108lbs/$/ft^2



Damplifier Pro by Second Skin Audio – www.secondskinaudio.com



Mass: 0.6lbs/ft^2

Overall Thickness: 2mm

Foil Thickness: 6.5mil

Price per bulk pack (36.5SF): $186



Price per square foot: $5.10 and mass per dollar per square foot – 0.118lbs/$/ft^2



RAAM BXT II by RAAMaudio – www.raamaudio.com



Mass: 0.52lbs/ft^2

Overall thickness: 1.52mm

Foil Thickness: 4mil

Price per bulk pack (37.5SF): $90



Price per square foot: $2.40 and mass per dollar per square foot – 0.217lbs/$/ft^2



B-Quiet Ultimate by B-Quiet – www.b-quiet.com



Mass: 0.35lbs/ft^2

Overall Thickness: 1.6mm

Foil Thickness: Not listed

Price per 50SF roll: $130



Price per square foot: $2.60 and mass per dollar per square foot – 0.135lbs/$/ft^2





V-Max by Cascade Audio – www.cascadeaudio.com



Mass: 0.35lbs/ft^2

Overall Thickness: 1.52mm

Foil Thickness: 4mil

Price per



Fatmat – www.fatmat.com



FatMat: 1.27mm thick, $80 for a 50SF roll ($1.60 per square foot) (rubber based)

Rattle Trap: 2.03mm thick $110 for a 50SF roll ($2.20 per square foot) (rubber based)

MegaMat: 1.78mm thick $130 for a 50SF roll ($2.60 per square foot) (Butyl based)





eDead by Elemental Designs – www.edesignaudio.com



eDead 45 (45mil thick) Butyl based: $1.00 per square foot comes as a roll

eDead 80 (80mil thick) Butyl based: $2.00 per square foot comes as a roll
 
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jdc753

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Awesome write up Josh. Answered alot of questions I had. And will be a good reference when I do my truck.

Thanks for the info.

Thanks, I'm always happy to help out, hoping to start working on an installation specific one next, and then cover more "advanced" tricks and techniques that I've seen done in competition grade installations.


I vote for this to be a sticky

Thanks, thats kinda what I am hoping it can become
 

ford_trck

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So I am looking to quiet the exterior noises in the truck. I would want to use step 1 and if there is room possibly step 2 also?
 

Ad8 PRODIGY

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Thanks, I'm always happy to help out, hoping to start working on an installation specific one next, and then cover more "advanced" tricks and techniques that I've seen done in competition grade installations.

That would be sweet, I dont like doing things on the truck half assed so it will can help to know those things...
 

jdc753

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So I am looking to quiet the exterior noises in the truck. I would want to use step 1 and if there is room possibly step 2 also?

Yes, for that probably can use partial coverage on step 1 (based on budget) and then continue with an ensolite or MLV layer with full coverage as those would be the best to combat the tire/exhaust/engine. Obviously full coverage on both would be the best, but the damper can accomplish most of its task with as little as 25% coverage.

That would be sweet, I dont like doing things on the truck half assed so it will can help to know those things...

...and knowing is half the battle!

Same here, luckily with my job there are times I get plenty of research time to learn how to do things. so hopefully I can save some people some time and effort in learning the hard way.
 

ford_trck

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I'm hoping that later this year I can do the door skins at-least and next year just pull the interior and do everything. Hopefully even convert my cloth seats to leather.
 

jkidd_39

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Great info. I priced everything I needed from sounddeadenershowdown.com a few months back for a 05 F350 crew cab and it will run about $700 in materials. Just for anyone that's curious.


Sent from my iPhone using Tapatalk while pulling a 36ft gooseneck and not paying attention to the road.
 

AKHILF

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I dont have that much in my crew cab. I would bet $400 tops with dynamat extreme. Would have been even cheaper if I could have gotten the rammat shipped up here.
 

BigRed97

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damn now i want to pull the crew cab apart again to add step 3!!!

it has 100% coverage of step 1 and step 2(and the noise reduction is incredible)

great write up Josh!
 

Smokin6-0

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Wow perfect timing on this thread. I just pulled the complete interior out of my 97 CCLB. I did this to replace carpet and have the seats redone. Anyway I thought that I would jump on here and see what I could find about making it a little quieter. First off I dont really want to spend more than $200, so can I even get any benefit from that? Secondly, I will actually have the dash out soon so I was wondering if it would be a good idea to do anything with the firewall? My truck is a 5 speed and it seems that a ton of noise comes through the access panel in the tranny tunnel, is there anywhere else that I should focus? I don,t expect to make this truck silent or even quiet. I would just like to mellow it out some so that I can talk on the phone. Thoughts?
 

CamTom12

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I'm not gonna lie, at first ya'lls avatars confused the **** out of me and I thought it was just one of you having a conversation with yourself, then I scrolled up and down a few times to see usernames and Dom looked like he was having the conversation between ya'll LOL
 

Tonka350

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thanks for the info! I am actually in the process of dynamatting my entire interior right now....IT'S A PITA! but it's working already and I've only done the rear doors so far. doing the fronts today so we'll see how well that works.....waiting to get my new carpet, seats and headliner before I do the rest of the truck. Do you recommend doing the firewall or does the rest of it pretty much take care of the firewall not being done?

Chad
 

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