What can I use as a substitute for MLV?

[lithium 358]

 

Nothing wrong with the CCF, but not needed. There are other methods/products if supply is an issue for you due to your location.

I think there won't be any problems sourcing closed cell foam.

 

You should find some goosd products in Europe, maybe not in bulgaria.

Try to find some UK or French websites.

 

Focal makes products for that, some others too.

Good luck

I am trying to save on shipping cost as the material needed is quite heavy. In other words, it has to be local.

 

https://www.facebook.com/silentcoat

 

you should be familiar with this product

Thank you for that. I might crab their vibration dampening products, but I am not sure about their sound isolation products.

They marked polyethylene foam as their sound absorbent product, but I can't find it's weight anywhere. And it's has self adhesive, combine that with the word "foam" and I am not sure it's the right thing for the purpose.

 

Another company I found was STP, but I am not convinced about their products either.

http://stp-distribution.com/en/products/

 

They market products 10 times lighter than SSD MLV to be their noise insulation.

For example :

http://stp-distribution.com/en/products/sound-insulation/stp-spl/

Weight: 0.37 kg / m²

MLV is 4.88 kg/ m²

 

http://stp-distribution.com/en/products/sound-absorption/stp-vbt/

Almost 4 times thicker than MLV and more than 50% less weight.

 

I know that air is a good sound insulation, but where else is my mistake in not believing in these products?

 

 

the effectiveness of a barrier material provides is based on the weight per area. a light barrier will block some high frequencies but low frequencies will pass through. for example, if you have a car with a rear seat (not backed with metal or plastic) you don't lose much bass when you dont lay them down. 

 

for absorption you need very thick material to actually absorb anything in the audible spectrum. thats why you rarely see them used (correctly). SDS's thinsulate is the only absorber i've heard that is worth using in a car. even then you're mainly only using it between the headliner and roof. this article seems decent at explaining stuff... the  quarter wavelength section explains why these thin foam products fail to absorb much of anything. 

 

i'm not familiar with their products but if they have something with a similar lb/ft^2 or the metric equivalent that is what you need to find.  those products will not do shit compared to mlv or anything else with a similar spec. 

 

edit: something on closed cell foam, i think Don mentions that some inferior products will compress over time 

Edited February 7, 2014 by lithium

[lithium 358]

those graphs next to the products are hilarious. 

[The enD 467]

Thank you, lithium. I'll read the article for sure.

 

None of their products come close to the weight per area of MLV.

 

Another thing I was wondering is what's the weight of Don's CLD tiles.

I might use some of the vibration dampening materials these companies sell, but I don't know how they compare to the tiles.

[lithium 358]

weight of the cdl doesn't matter so much i believe. i think the important specs are thickness of the butyl, thickness of the constraining layer (alum), and the adhesive. if you read the don's section on cdl tiles you might get a good idea for what to look for. 

[The enD 467]

But if the butyl is not heavy and air infested how is it going to add weight to a panel to stop if from vibrating and resonating?

[lithium 358]

it doesn't mass load the panel.

[lithium 358]

read don's section on the cdl tiles. 

[The enD 467]

read don's section on the cdl tiles. 

I've read and re-read it, but I still down understand how to compare the tiles to similar products and decide which is superior and suits my pocket.

 

CLD tiles have a thickness of 2mm 0.2mm of which is the foil

 

http://stp-distribution.com/en/products/vibration-absorption/stp-silver/

This product for instance is the same thickness of 2mm but it's foils is 0.06mm.

Weights 3kg per square meter.

[lithium 358]

i think the stp gold might be more comparable to don's stuff. you're aiming for ~25% coverage with the best product you can get.

Edited February 7, 2014 by lithium

[j-roadtatts 1,129]

After re-reading this thread I am unsure of your purpose. Are you looking for a barrier as stated in the beginning or are you looking to stop panel resonance? If your building a wall and you are just looking to stop the panel's from resonating, brace the panels with the box and be done with it. If you are looking for a barrier I am curious where in the car are you using it? 

[The enD 467]

I was looking only for a barrier to replace MLV, but I am now looking for another company's product as well, to use as vibrating dampener.

I will be using both things I am looking for all over the car for complete sound deadening, combined with CCF.

[j-roadtatts 1,129]

If you are walling the car you shouldn't need to do the whole car. You can brace any panels behind the wall. 

[The enD 467]

I don't like the idea of bracing, I want to use the space.

[j-roadtatts 1,129]

So you are going to build the wall/box without attaching it to the vehicle?

[The enD 467]

 

This is how it looks behind the wall. Basically anything from the back seats to the taillights needs attention. I am not going to focus mainly on the back side of the car as the wall provides decent sound insulation, but it still need to be threated because of rattle and tire noise.

 

The metal under the seats and middle console, firewall, doors, footwells and roof will be my major places to deaden.

[///M5 2,833]

But if the butyl is not heavy and air infested how is it going to add weight to a panel to stop if from vibrating and resonating?

Do NOT mix up a deadener and a barrier.

Creating a sound barrier requires one and only one thing. Mass. The lighter the weight the worse the barrier. /discussion

Deadener is a completely different beast. The goal with a deadener is to change the damping and modal frequency response of the target panel. While you can do this with mass, it is a really shitty way to do the job. It would be akin to making your car heavier instead of using shock absorbers. While of course this will indeed stop the car from bouncing around, it is a rather shitty way to do it and will create a terrible riding vehicle. In the case of a panel, something similar will occur as you will change the frequency of the resonance and affect the damping but not in a way that is what anyone would call successful. Instead using a constrained layer you can constrain (ie add damping) the resonance and convert the energy into heat. This is why a viscoelastic material is needed along with STRONG adhesive and a reasonably robust (ie thick) aluminum layer. Of course it is easy to go overboard on anyone of the layers and add no benefit.

As for the sound absorber, this normally requires thickness. This works akin to the deadener but for air. Basically we have to convert acoustic energy into heat. You've probably seen acoustic traps in offices and other spaces. These are normally very thick to even be able to "absorb" higher frequencies. In a car this is impossible. The clever engineers at 3M though engineered a technique of taking a long drawn fiber that forces the sound to think it is traveling through a much thicker material than it is. Acoustic Thinsulate is extremely effective when placed inside pillars and other areas where sound is transmitted through. OE's spend TONS of $$ on doing Acoustic Transfer Path analysis to determine what is coupled where, how things propagate and low cost low weight mechanisms to improve them. I've had the engineering team at 3M give me thinsulate for my cars since the mid-90's. Of course I can cheat and mimic tests done by the OE's to optimize, but there are some great locations to use this product. For what you've described and needed so far though this is not where I'd start.

[j-roadtatts 1,129]

The pic explains a lot. I have NO sound deadening behind the baffle in my ride, but DO have a continuous barrier in front of the baffle. In other words if you isolate the rear of the car from the passenger camber you should not need to worry about deadening behind the wall. 

[///M5 2,833]

If you want to spend some time understanding things read Wiki on:

Damping

Modal Analysis

Transfer Path Analysis

There are a ton of other topics as well, but this is a start. We own the most advanced test lab for acoustic damping & modal analysis in the world. If I can answer other questions let me know. The OE's all come to me for help regularly. I can't write a dissertation on here due to NDA's but can surely share how to help and understand needs in your situation.

[///M5 2,833]

The pic explains a lot. I have NO sound deadening behind the baffle in my ride, but DO have a continuous barrier in front of the baffle. In other words if you isolate the rear of the car from the passenger camber you should not need to worry about deadening behind the wall.

I'd still take care of rattles but until tire noise or some other aspect is of bother a generic cover all solution I would not employ.

[///M5 2,833]

And exactly why I have no respect for Ant. You've seen my public discussions but it all stemmed from a private discussion where I offered to do some unbiased tests. Don was all for it and we discussed techniques for a while. The Anthole understood nothing and acted like a dipshit during the whole discussion. Don & I decided not to do it in the end due to the fact that the variables in the test article (not the applied damping) and overall fixturing concerns would create confusion in reading the test results. This is something the OE's battle everyday and don't always understand and why 3M contracted me to help in the first place.

[The enD 467]

Аppreciate the info, guys.

Will be reading on Wiki, Sean.

 

So I think I have understood how a barrier works and I know what to look for now.

When it comes to deadener seems like Don has one of the best product out there.

The products I've posted above have very similar aspects, but I am worried how much the foil thickness will affect the performance. CLD's have 0.2mm, STP products have 0.1mm or 0.06, that's like two to three times less.

But if Don has spend the time and money on research I am sure there is a reason it's that thick and it's what I should be aiming to find.

 

[///M5 2,833]

Beware, it isn't just the foil. The Butyl formulation and adhesive are HUGE!

[The enD 467]

My best is just to go with Don's stuff it seems.

[///M5 2,833]

In general that is a safe assumption. Not saying there isn't something else, but good luck actually getting information out of the company who supplies it.

[Julian 641]

Expanding foam has always been my go to stuff for walls but it's justabitch to get off if you ever decide to unwall it