Carpet Padding?

D

Diffusion

Future Astrophysicist
I have a possible suggestion... anyone used carpet padding for sound absorbtion? something like this...

carpet-padding.jpg


For those who dont know it is the stuff that goes under your carpet and it is basically hundreds of little pieces of foam all stuck together... and it is reasonably cheap... I was wondering has anyone ever tried using this in a vocal booth for example or if anyone knows its NRC at different frequencies... or could anyone take an educated guess at its absorbtion qualities...
 
Listen, if the stuff was any good at noise reduction that fact would be listed in its features and it would have published specs. Manufacturers are constantly looking for new uses for their products and if this had any hope of being a good choice for the money they would be promoting it as such.

It is not as though semi-rigid fiberglass and mineral wool were all that expensive.
 
shit bitch no need to get all defensive... i unno i just never heard anything about it and was curious...
 
On the contrary, padding is rated for NRC. Here's one example:

http://www.wolfeflooring.com/installation_cushion.asp

That product has an NRC of 0.69, which is good, but without a detailed frequency chart it's hard to know its exact performance. Carpet installations are generally more concerned with transmission than absorption, anyway.

Could it be used on a wall? I suppose, but given its non-rigid nature, it would be more of a chore to fashion panels. I'm also not sure what the flame retardant properties of the material are, but that should be in the manufacturer's info too. I don't know about standards for floors vs. walls either; I imagine walls are more strict.
 
The question becomes WHERE? NRC is an average of the coefficients from 125-4k. It's probably about 1 at 1k through 4k which means that it's basically diddly below 1kHz. Pretty much the same as carpet - mids and highs only.
 
Regarding the fire rating on the pad. I'm no expert but when you think about it, its on the floor already, can't be that much more unsafe in a wall. Just seems like common sense to me, but then again i tend to think too much.
 
jonnyc said:
Regarding the fire rating on the pad. I'm no expert but when you think about it, its on the floor already, can't be that much more unsafe in a wall. Just seems like common sense to me, but then again i tend to think too much.
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Fire tends to travel up and carpet padding is under the carpet normally.

There are different standards for things that are going to be on floors, walls and ceiling at the same time.
 
bpape said:
The question becomes WHERE? NRC is an average of the coefficients from 125-4k. It's probably about 1 at 1k through 4k which means that it's basically diddly below 1kHz. Pretty much the same as carpet - mids and highs only.
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A lot of that has to do with thickness. What you say is also true for 1/2" rigid fiberglass.
 
To a point - yes. However, the density and flow resistivity of the rigid fiberglass will let it perform better for the same thickness - but still not much more than mids and highs.

My problem with the carpet pad is that from what the picture shows, it's likely got a relatively high rubber content in it - hence it won't pass sound very well which makes it a poorer absorber to try to work with multiple layers to get it to perform well down lower.

Carpet pad is specifically designed to reduce impact noise. That's great for isolation if that's what you need. However, inside the space for decay control, it wouldn't be my first choice.
 
mshilarious said:
That product has an NRC of 0.69, which is good, but without a detailed frequency chart it's hard to know its exact performance. Carpet installations are generally more concerned with transmission than absorption, anyway.

Could it be used on a wall? I suppose, but given its non-rigid nature, it would be more of a chore to fashion panels. I'm also not sure what the flame retardant properties of the material are, but that should be in the manufacturer's info too. I don't know about standards for floors vs. walls either; I imagine walls are more strict.
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1st off - let's make certain here that we realize we are talking apples and oranges.

The NRC of .69 is for a high end 32oz synthetic fiber cushion - not for the polyurethane cushion that's the subject of the thread.

Next - to the best of my knowledge (which is fairly extensive) no carpet pad has ever been tested for application to a wall - in fact the only carpet that I am aware of that has been tested and approved for wal covering (and this is only in fairly small quanities) is Berber - in a direct application - no pad involved. I don't even know that carpet pad has ever even been tested seperately from the carpet that rests on it. After all - the carpet/pad installation is part of a tested assembly - and that's as a whole. You can't install pad as a finished floor covering material.

Next, there is a tremendous difference between horizontal and vertical installations of material - whic is why there are different testing requirements for each.

For Example:

Floor Coverings:

ASTM D2859 - Flammability of Finished Textile Floor Covering Materials

ASTM E 648 - Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Energy Source [NIST (NBS) Flooring Radiant Panel]

NFPA 253 - Equivalent or similar to ASTM E 648

Wall Coverings (on the other hand):

UBC 8-2 Evaluating Room Fire Growth Contribution of Textile Wallcovering (Formerly UBC 42-2)

NFPA 265 Equivalent or similar to UBC 8-2
Foam PLastics (on yet another hand) have a totally different test criteria:

UBC 26-3 Room Fire Test for Interior of Foam Plastic Systems (formerly UBC 17-5)

Sincerely,

Rod
 
Rod Gervais said:
1st off - let's make certain here that we realize we are talking apples and oranges.

The NRC of .69 is for a high end 32oz synthetic fiber cushion - not for the polyurethane cushion that's the subject of the thread.
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Yes, agreed. If you read the early responses on the thread, it was alluded that padding had no acoustic value, which obviously isn't true. That particular product was just something I pulled off pg. 1 of a Google search on "carpet padding nrc".

Thanks for the authoritative info on fire ratings. Other than that, I think I'm sorry I walked into this snowball fight :(
 
What about carpet padding as mass inside a wall. I'm considering using a carpet pad/drywall combo for mass inside the walls purely for isolation. Any comments on this idea?
 
jonnyc said:
What about carpet padding as mass inside a wall. I'm considering using a carpet pad/drywall combo for mass inside the walls purely for isolation. Any comments on this idea?
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Jonnyc,

I don't believe you would see any real benefit from this.

It doesn't have enough mass to really amount to anything - and is more expensive than using fluffy fiberglass insulation - which already gives you the bang for the buck you need in additional isolation.

The real big problem with a question like this is that no one can really give you a perfectly definitive answer as to what it would or wouldn't do.

All of the acoustic theory in the world does not amount to much more than a hill of beans without testing being performed.

Models perform differently in tests than they do on paper (a lot of the times - not all) and thus empirical data is the only real meaningfull data at all.

Seeing as this product was not manufactured for what you suggest - no one anywhere in the world has ever paid to have a test performed on it in this use.

So no "expert" can give you any positive feedback - and none worth listening to ever would.

If someone ever says to you - "yeah that would work just great" or something to that effect - run away from them as fast as your feet can carry you - because they are blowing smoke out of their butt. Getting caught in the potential crossfire from that is not anywhere I would want to be........... lol

Sincerely,

Rod
 
I bought some of the stuff for side/back wall absorption yesterday and propped it up temporarely... and for the purpose...it works.
 
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