Sound Deadening

[kevman5002 10+ year member]

I know I'm just linking a lot of similar products, but how would this fair over a layer of Damplifier, say instead of Luxury Liner or some other foam? Link Again, does anyone have experience with this?

 

[Rudy 10+ year member]

You are sort of mixing up some basic concepts. Sound deadening is a very broad term and all sorts of products can fit under that umbrella. That make it almost meaningless.

The product group most often called sound deadeners are the vibration dampers. Second Skin Damplifier, Dynamat Xtreme, Cascade V-Max, Hushmat and RAAMmat all fall into this category. As a side note, Hushmat is decent stuff, at least the black version that I've seen is. My only complaint is that the foil is a little thin and it has a rather thick layer of black paint on it that adds little value that I can see. Cascade V-Max is also black, but it has a nice 4 mil foil that is anodized black - big difference.

You'll want to pick one of these to treat large, mostly flat panels to eliminate resonance. After that, you really need to define your goals. If reducing noise, you will almost certainly want to use something like the mass loaded vinyl barrier you linked. This is intended to block sounds like engine, tire and exhaust noise. You need to completely shield the the car from the noise. Picture the heat shield on the space shuttle.

The choice of open cell vs closed cell foam in this and other applications is largely determined by the conditions the material will encounter in use. Closed cell is less effected by moisture and generally chemical exposure so should be chosen anywhere exposure to harsh conditions may occur. The foam in intended to create a cushion of air to lift the heavy barrier from the substrate and OCF will theoretically do a better job of that. The vehicle floor may be an exception to this because of pressure from feet, packages, etc. CCF is less likely to compress. While it may not work as well under ideal conditions, it may well be superior in actual use.

In places where you don't need a barrier, it is often useful to layer thin sheets of CCF over the vibration damed parts of the vehicle. This does very little on its own to block sound, but can reduce reflections and fill voids through which noise/sound can travel. OCF would be more effective here too, but because of the harsh environment, CCF is a safer choice.

 

[kevman5002 10+ year member]

Thanks for all your help. My main goal is to eliminate as much road noise as possible. I hate having to yell to have a conversation.

I think I have a fairly good idea of sound dampening compared to sound absorption. I've just been researching both at the same time so my thread has become kind of jumbled.

 

[FoxPro5 5,000+ posts]

Keep going with your STC research, then if your goal is to block road noise.

In one of the links you posted above, they claimed the material was "extremely lightweight" and was a "excellent sound deadener." If we know that "deadening sound" in this instance is mass-dependent, you don't have to be a rocket scientist to know how much BS their selling.

MLV by itself does have a nice STC, but it's not going to function as well until it's mechanically isolated from the surface. The air spring created by the decoupler is critical for transmission loss performance, so much so that you can expect an additional 18dB loss above the resonant frequency in question with a decoupled barrier vs plain old MLV alone.

LL has that decoupler, however the foam is weak and is easily compressed. It will also take on water due to it's open cell nature. That leaves only a few places in your car where it will optimally perform, the firewall being one of them (as long as you don't crush it or get it wet.)

Deadening mats that are purposely coupled to a resonant surface are weak barriers...no matter how many layers you use....due to what I just outlined above.

The last thing anyone needs to understand is that sound deadening and sound blocking is frequency-dependent. Most people that sell these products would love for you to believe in fairy tales - most notably the ability of their products to work EVERYWHERE and do EVERYTHING. This is an outright lie.

 

[kevman5002 10+ year member]

Ok, the more I read the more I realize I don't know. Here's what I'm thinking (and keep in mind I can't afford to get damplifier pro and Luxury liner pro for the whole car.) A layer of American MLV and then a layer of this. I think even though they say sound deadener they mean more of a sound absorber. As you pointed out it's very light. So it won't do much dampening, but it's closed cell foam so it should absorb well. And the MLV is fairly heavy so should take care of the dampening.

Any flaws in my logic? Any suggestions in a similar price range? Thanks for all your insight so far.

 

[ItalynStylion 10+ year member]

just od the second skin, its worth the money
the stuff is still exactly where I put it.

I has survived a 110+ texas summer

 

[mastersstereo]

I know there are a lot of great sound deadening products on the market. We used to use Dynamat (which is a great product), but now we've moved to HUSHMAT which is a great product that already has adhesive on one side so there is no need for heat gun. It's a great product that eliminates many acoustic problems and outside noise.

Visit:

http://www.masterscarstereo.com

 

[ItalynStylion 10+ year member]

I know there are a lot of great sound deadening products on the market. We used to use Dynamat (which is a great product), but now we've moved to HUSHMAT which is a great product that already has adhesive on one side so there is no need for heat gun. It's a great product that eliminates many acoustic problems and outside noise.
Visit:

http://www.masterscarstereo.com

Nearly all sound deadening mat has an adhesive layer on one side. The heat gun is not used to get it to stick, it's used to get the deadener more flexible so it's easier to work with.

 

[jgonino 10+ year member]

I too am facing a choice here. I think I am going to order a couple rolls of the Raammat, and leave it at that. I have a loud factory exhaust, so I am going to layer the floor of the trunk, and cover the doors, and hatch. Whatever i have left i will just put in some extra crevices or sell.

 

[kevman5002 10+ year member]

I'm with you, the more I search and read the more I think Raamat is the best I can afford. I'll probably also do a layer of their ensolite, or the Insulator I've linked before.

 

[skateboardkid 10+ year member]

Raamat is the best cost / effective sound deadner according to several articles and users here.

 

[audioholic 5,000+ posts]

Nearly all sound deadening mat has an adhesive layer on one side. The heat gun is not used to get it to stick, it's used to get the deadener more flexible so it's easier to work with.

The old asphalt based mat did have glue that was heat activated. The hotter you got it, the stickier the stuff would get.

 

[Rudy 10+ year member]

Ok, the more I read the more I realize I don't know. Here's what I'm thinking (and keep in mind I can't afford to get damplifier pro and Luxury liner pro for the whole car.) A layer of American MLV and then a layer of this. I think even though they say sound deadener they mean more of a sound absorber. As you pointed out it's very light. So it won't do much dampening, but it's closed cell foam so it should absorb well. And the MLV is fairly heavy so should take care of the dampening.
Any flaws in my logic? Any suggestions in a similar price range? Thanks for all your insight so far.

That MLFV you've linked to doesn't have a foam layer. You really want that for horizontal use. It doesn't have to be part of the product itself, but you want a layer of foam between the barrier and the sheet metal. I also think you will need at least some vibration damper. At least enough to treat open areas on the floor and roof and definitely for vertical surfaces.