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Home Carpet padding as sound deadner?

My negibor just redid her home, will this work?

There is a ton, If you want some and live near the gurnee, IL area Let me know there is plenty to go around.
 

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Apparently i can't link as a new member :(

Reposting for your info, shoot me a pm if need more info on the foam or can't find it on Amazon.
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Please don't use home carpet padding. It may work a little but you will get so sick of the smell of that stuff. and it WILL stink!

There are two things you can use. Dynamat type material (dynamat, raamat,second skin, edead) which is actually supposed to be used for vibration control.

Then there is foam (still not home carpet foam), which is Actually For sound deadening. Amazon sells it cheap and it is very easy to use and cut. If you need pics or tips just shoot me a PM. I did my entire car with both dynamat and the edead foam. Rides and sounds like a new car now.
 

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Using foam as a SOUND BARRIER is useless. It only blocks frequencies whose wavelengths are at least 1/4 of its thickness, so even with 1/2" foam you will only be blocking frequencies waaaaay above 20khz, or outside the range of human hearing.
 

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Then there is foam (still not home carpet foam), which is Actually For sound deadening. Amazon sells it cheap and it is very easy to use and cut. If you need pics or tips just shoot me a PM. I did my entire car with both dynamat and the edead foam. Rides and sounds like a new car now.
While you did achieve something by using the CLD (dynamat) to control panel borne vibrations, the foam did absolutely nothing to block sound from coming into your vehicle. Adding a layer of MLV on top of that foam however, would actually do something to reduce noise, assuming the foam you used actually has a good compression resistance rating. And unless you used neoprene foam, I have a feeling your foam's compression rating sucks.
 

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Some well made polyethylene foams can have with good compression recovery too, depending on how they're manufactured.
 

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Some well made polyethylene foams can have with good compression recovery too, depending on how they're manufactured.

Very true, forgot about those, good point.

p.s. I love your sig. :smug2:
 

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I'd think it would to some degree. If you want to absorb long frequencies it will probably work better than the foam, which does nothing like people mentioned. I plan on using some old fashion home fiberglass insulation.
 

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Is it foam? Then no.

Is it MLV? Then yes.

/End of thread.
\begin thread....

Mass is mass is mass is mass. Did you know mass is mass and that more mass per unit surface area is THE name of the game for sound refraction/blocking? Yea, it's true. No mo MLV dogma, ok? Thanks.

Don't bother with carpet padding anything other than padding your carpet. Trust me, I filled a city garbage bin fill of the stuff from my car back in the day cuz I read online that it was a good idea to put in an automobile.
 

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Using foam as a SOUND BARRIER is useless.
Not useless. If it has good density and mass, as metioned it can be very effective. Good luck finding such foam, though.

It only blocks frequencies whose wavelengths are at least 1/4 of its thickness, so even with 1/2" foam you will only be blocking frequencies waaaaay above 20khz, or outside the range of human hearing.
On paper, yea. In real world testing you can see fairly respectable NRC figures (even some STC's, too) from like 6# 1/2" composite foam or cotton products.

The 1/4" wavelength thing has to do with absorption. If you study Sabine numbers, you can find absorbers with higher than 1.0 NRC figures do to the this affect at the edges of the material absorbing more than the middle.
 

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\begin thread....

Mass is mass is mass is mass. Did you know mass is mass and that more mass per unit surface area is THE name of the game for sound refraction/blocking? Yea, it's true. No mo MLV dogma, ok? Thanks.
I only said MLV because its relatively easy to find, pretty cheap, and somewhat easy to work with. Most people won't bother with making a 'sand glue sandwich' or using lead in their car, and I never said that MLV is the only option out there.
 

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Not useless. If it has good density and mass, as metioned it can be very effective. Good luck finding such foam, though.
Again, most people won't ever be able to find such dense foam that would make it useful in that application, and as such most foam people actually think of or use actually IS useless. Just because an esoteric version of it exists out there somewhere doesn't mean the average person knows about it, and it definitely isn't what they think of while putting ensolite in their car.
 

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?/!?
 

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From the picture you posted, that looks to be an insulation they call "Jute". It seems to be heavily used by car manufacturers as I've seen tons of it in most of the cars I've taken apart.

I wouldn't bother putting it in a car for a number of reasons:
1) it doesn't seem to be a very good sound insulator (although it might be good thermal if you need that) -- if you're going through all the trouble, you might as well spend a hundred bucks (or more) and get some much better materials as others have suggested.
2) it will absorb moisture, ie at some point start smelling bad, maybe mold or even cause rust if near sheet metal
3) it's probably highly flammable
4) it's thick, so your carpet might not stay right

I imagine the Jute used by car manufacturers is specially treated for issues 2 and 3, doubtful that the home version is.
 

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I only said MLV because its relatively easy to find, pretty cheap, and somewhat easy to work with. Most people won't bother with making a 'sand glue sandwich' or using lead in their car, and I never said that MLV is the only option out there.
At some point you are just looking for low cost substitutes for low cost substitutes. MLV was developed to be a low cost substitute for lead. Most of the alternatives I've seen have enough deficiencies to not be worth the effort. If you can string something together out of material that is free to you, you may come out ahead of the game. Walking the aisles at Home Depot probably won't pay off It's sort of like looking for a cheaper version of cubic zirconia - you're already 99% of the way there.

Again, most people won't ever be able to find such dense foam that would make it useful in that application, and as such most foam people actually think of or use actually IS useless. Just because an esoteric version of it exists out there somewhere doesn't mean the average person knows about it, and it definitely isn't what they think of while putting ensolite in their car.
Right, rule out the idea that thin foam will be any kind of barrier or do much vibration damping. It's good for two things - attenuating high frequencies and isolating adjacent objects or surfaces. It's possible that the OP's carpet padding might have some use - subject to all of the caveats already listed, but only as a substitute for foam, the least important and least expensive ingredient in the mix.
 

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I used some for my truck roof on top of damplifier, not for sound but for insulation. Along with a sun shade in the front window it works well on hot days.

Plus for a week or so you get that new house smell:D
 

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Right, rule out the idea that thin foam will be any kind of barrier or do much vibration damping. It's good for two things - attenuating high frequencies and isolating adjacent objects or surfaces. It's possible that the OP's carpet padding might have some use - subject to all of the caveats already listed, but only as a substitute for foam, the least important and least expensive ingredient in the mix.
That's pretty much what I was trying to say, that using thin foam specifically as a noise barrier won't get you anywhere. I never said it doesn't attenuate very high frequencies, or that it doesn't do an admirable job of isolation surfaces from vibrations. In fact, I use to to keep panels from vibrating against one another and it works quite well.
 

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Ever worked on an older (pre 1970s) car? The carpets - and behind the back seat, along the firewall, and several other places - were lined with jute carpet pad. It works well, if it's relatively thick.

It works in doors, too, if you can handle 3/4" thick pad and figure out a good way to support/seal it to the metal.
 
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