so i don't understand why MLV is all the new rage when the old butyl stuff seems to quite similar. If it's only mass that counts lb for lb shouldn't they be the same? is the vinyl material itself (as opposed to it's mass) a better accoustical blocker?
Mass loaded Vinyl VS Butyl
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Not sure I understand what you mean. Butyl is typically part of CLD tiles, which are dampers, not barriers. MLV is not a damper, it is a barrier product. They do different things.
In the "old days", we just slapped a ton of CLD tiles down and that was that. But using a multi-layer approach seems to produce better results with less cost and sometimes less weight.
In the "old days", we just slapped a ton of CLD tiles down and that was that. But using a multi-layer approach seems to produce better results with less cost and sometimes less weight.
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Two tottaly different products and applications.
Butyl is an elastomeric product that gets laminated on to a stiff aluminum panel to create a constraint layer damper.
These products get applied on top of vibrating sheet metal to kill the resonance and the noise that is emitted from the resonance. Stucture borne noise.
Mass loaded viny is usually laminated to a decoupling material like open or closed cell foam, which gets applin on top of the vibration damper in order to block (or at least reduce) the transmission of airborne noise.
Mass is king when it comes to air borne noise reduction which is why an argument can be made that 2 layers of Constraint Layer Damping mats works just as well as one layer of each products, but in reality it does not work that way.
Adding multiple layers of a constrint layer damper WILL reduce structure borne and airborne noise, but requires much MUCH more than it would take when using the decoupled barrier approach on top of a vibrations damper.
There are a few other things involved besides pure mass that will contribute to better noise rejection. The limpness and pliability of the material used.
the density and thickness of the decoupling foam.
We are working on a new mass loaded material that is looking very hopeful. It is a constraint layer barrier system that is either going to totally change the barrier concept, or flat out fail. Something I have been working on for quite some time and hope to have ready in the next 6 months. Exciting stuff but might turn out to be nothing. Gotta produce it and see how it fairs.
Your best bet is to treat each problem individually.
Attack the structure borne noise with a damper.
Treat the airborne noise with a barrier.
Butyl is the best elastomeric adhesive for CLD mats
Vinyl is the most popular material for mass loaded decoupled barriers.
Two problems, two solutions, one great result!
ANT
Butyl is an elastomeric product that gets laminated on to a stiff aluminum panel to create a constraint layer damper.
These products get applied on top of vibrating sheet metal to kill the resonance and the noise that is emitted from the resonance. Stucture borne noise.
Mass loaded viny is usually laminated to a decoupling material like open or closed cell foam, which gets applin on top of the vibration damper in order to block (or at least reduce) the transmission of airborne noise.
Mass is king when it comes to air borne noise reduction which is why an argument can be made that 2 layers of Constraint Layer Damping mats works just as well as one layer of each products, but in reality it does not work that way.
Adding multiple layers of a constrint layer damper WILL reduce structure borne and airborne noise, but requires much MUCH more than it would take when using the decoupled barrier approach on top of a vibrations damper.
There are a few other things involved besides pure mass that will contribute to better noise rejection. The limpness and pliability of the material used.
the density and thickness of the decoupling foam.
We are working on a new mass loaded material that is looking very hopeful. It is a constraint layer barrier system that is either going to totally change the barrier concept, or flat out fail. Something I have been working on for quite some time and hope to have ready in the next 6 months. Exciting stuff but might turn out to be nothing. Gotta produce it and see how it fairs.
Your best bet is to treat each problem individually.
Attack the structure borne noise with a damper.
Treat the airborne noise with a barrier.
Butyl is the best elastomeric adhesive for CLD mats
Vinyl is the most popular material for mass loaded decoupled barriers.
Two problems, two solutions, one great result!
ANT
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why do people put dampener on the outside skin of the door? If the holes are covered on the inside skin and its sealed, wouldn't we not hear the outside door vibrations?
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If metal resonates, you'll hear it. CLD tiles inhibit resonance and move the resonant frequency away from the frequencies we care about.
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Vibration dampers also help strengthn up the sheet metl in the doors, which provides a more stable environment for the door speakers to perform in.
Imaging installing a sub woofer in a cardboard box, and how much energy (pressure) would be lost because of how week the enclosure walls are.
Now put that same sub in an mdf enclosure and you will see an incredible difference.
Same basic concept applies here, only on a smaller level.
ANT
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I'll let ANT handle this one, but the short answer is "no" unless you are thinking of butyl in a way I am not.
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Sounds like you are thining about the cured and crosslinked butyl rather than the elastomeric adhesive type.
Innertubes for example are butyl. Some speakers and subs have butyl rubber surrounds.
This is a totaly different product from that of the adhesive type we are talking about.
If the butyl rubber sheeting you have is heavy and dense, then yes, it could get applied on top of the foam to creat a barrier. Vinyl is used widely becuase of its density and cost. I can't tell you the cost or the desity of the butyl sheet though since I do not work in that trade.
I would say, it would be a total waste of materials and money to apply a butyl based constraint layer damper on top of a foam product in an attempt to recreate the barrier effect. Most dampers do not weigh enough and mass laoded vinyl (raw) is cheaper thant most heavy cld mats. 1 lbs per square foot is the average weigh of the vinyl that is being used for these applications.
Hope that helps
ANT
Innertubes for example are butyl. Some speakers and subs have butyl rubber surrounds.
This is a totaly different product from that of the adhesive type we are talking about.
If the butyl rubber sheeting you have is heavy and dense, then yes, it could get applied on top of the foam to creat a barrier. Vinyl is used widely becuase of its density and cost. I can't tell you the cost or the desity of the butyl sheet though since I do not work in that trade.
I would say, it would be a total waste of materials and money to apply a butyl based constraint layer damper on top of a foam product in an attempt to recreate the barrier effect. Most dampers do not weigh enough and mass laoded vinyl (raw) is cheaper thant most heavy cld mats. 1 lbs per square foot is the average weigh of the vinyl that is being used for these applications.
Hope that helps
ANT
actually, i was thinking about the adhesive type (ie dynamat, etc). i realize that this is not as heavy as 1 lb/sqft unless you start to build up some significant layers. but if we're just talking mass then it could be done.
the reason is that i have some of this stuff left over and if i can use it in a barrier type application (as opposed to the traditional damper type) i could make us some decent sized barrier sheets for quite cheap.
the reason is that i have some of this stuff left over and if i can use it in a barrier type application (as opposed to the traditional damper type) i could make us some decent sized barrier sheets for quite cheap.
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Sounds like a silly misuse of the product to me, sorry to say. Find something else to damp with it - another car? family member's car?
One exception, it's a good material to use as "tape" for seam sealing the MLV. If you have excess that's one reasonable way to make good use of it in the barrier layer.
- D
why would this be a misuse? please elaborate on this. if all you are looking for is mass than this should do the trick (albeit it's not as dense as vinyl).
i'm trying to find out if there is something intrinsic in the vinyl *material* (desregarding density) that is better than butyl for barrier duty.
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The benifit of the vinyl comes in the cost to density & weight ratio.
To get a vibration damper to be as heavy as the 1 lb vinyl barrier you need a good amount of foil or adhesive and by that time it is quite expensive. the vinyl is heavy, and dense and less expensive.
Applying the damper on top of the decoupler foam will help some, but compared to using the right material for the application, it is a waste of money and material. Time too.
Hope that makes sense.
ANT
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Would you use a screw driver to butter toast? A butter knife to drive screws? You could, but it's not what they're designed to do. The reason I call it as misuse is simply because it will not be doing what it was designed to do.
I understand your thinking tho, it's hard when just reading about the stuff on the web. Once you get it in your hands and work with it things start to make more sense.
Keep in mind that MLV isn't just any ol' vinyl. There's three letters in that acronym for a reason! It's much thicker and heavier than anything you've seen on a camper top. When cutting it with a carpet knife, the blade dulls quickly and develops a notch where it passes through the stuff.
But putting your idea to the numbers, here's some comparisons:
MLV = 1.2lb/sqft plus a closed cell foam decoupling layer attached
foil backed butyl:
40mil = .35lb/sqft
60mil = .45lb/sqft
80mil = .60lb/sqft
So you'd need to cut and fit a decoupling layer of some sort, either closed or open cell foam. Then cut and fit either 3-4 layers of 40mil, 2-3 layers of 60mil, or 2 layers of 80mil. That's a LOT of work and you still wouldn't have as good of results. I wouldn't go that route even if someone gave me the 80mil free.
- D
i'm not trying to argue price. it's pretty clear that if you are starting from scratch that the MLV is a better deal and less work.
i'm was really just trying to understand if the only factor here is just mass (without regard for material/density) and the decoupler. have to admit i was pretty suprised at the hostility of some of the posts...
here you're just comparing mass. so setting aside how difficult the material is to work with and price a lb is a lb it seems (when it comes to a barrier). ant did briefly mention density but it seems more with respect to final weight.
i'm was really just trying to understand if the only factor here is just mass (without regard for material/density) and the decoupler. have to admit i was pretty suprised at the hostility of some of the posts...
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Well I hope I've helped some. Without getting into a physics definition of mass, it's about lb/sqft. Lead sheet is actually a common barrier product, used with a decoupling foam layer just like the MLV products.
- D
- D
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Yes, lead is the idea barrier septum.
More dense than mass loaded vinyl. But it is expensive. That is the only issue.
ANT
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