What is the life of acoustic foam?

ronhar

New member
About 5 years ago I used some left over acoustic foam from work. It was used to help with some machine noise and I wasn't involved in the actual use so I can't vouch for any specs. It may just be any brand but was supposed to have some acoustic properties. Any way I just glued on some magnets and stuck it onto the metal external door to my studio to maybe kill standing waves or reflections from the door. A few days ago I walked into the studio and a large chunk of foam from the center of the sheet was lying in the floor! When I felt of the foam it crumbled in my hand. I never wondered if this stuff had a life span. I don't use any other foam but I know it's a widely advertised product to "fix every acoustic problem you have". Anybody else had their studio crumble away?
 
Sounds like it was just cheap open cell polyurethane foam (which will dry out over time in warm dry environment). To cover a metal door and reduce high frequency reflections, use a moving blanket or old duvet. Or construct a framed mobable gobo with rockwool/compressed fiberglass that you can move into place, and out of the way when not recording.
 
I still have some foam from my first studio in the mid 90s. I dont use it anymore, but it hasn't disintegrated yet.

I'm sure it will, eventually.
 
I have lots of foam from various sources around the place, some has fallen apart and some has lasted many years. I just replace it when it falls apart. I find the real acoustic foam seems to last longer than the cheap egg crate style stuff.

The same happens to road case foam, it starts to go mussy and the sticky, time to re-foam the case.

Alan
 
I have seen foam like that disintegrate into powder. It was an heat insulation foam and it was when it was left in exposed strong sunlight through a window. The back of the foam was ok but the front of it facing the window just turned to brown powder which went everywhere when we picked it up.
 
foam does absolutely nothing to block or stop standing waves, it's physically impossible, you need multi-layer multi-density materials for that, for example a lead lined MDF and ply door that weighs over 100 KG will work. You are better off with using rockwool or owens corning if you in the USA in simple pine frames covered in hessian fabric, and if you space out the rockwool from the front of the panel, put hardboard on it and perforate it so that it covers 1-5% of the surface area you'll have an extremely efficient bass trap, not too difficult to make.
 
foam does absolutely nothing to block or stop standing waves, it's physically impossible, you need multi-layer multi-density materials for that, for example a lead lined MDF and ply door that weighs over 100 KG will work. You are better off with using rockwool or owens corning if you in the USA in simple pine frames covered in hessian fabric, and if you space out the rockwool from the front of the panel, put hardboard on it and perforate it so that it covers 1-5% of the surface area you'll have an extremely efficient bass trap, not too difficult to make.

I thought the idea was to 'absorb'? As does any material to an extent depending how good it is at sound absorption.
 
Depends what the foam is for, I have it on my studio doors but only to reduce the reflection, it’s not used for any serious absorption,
 
Depends what the foam is for, I have it on my studio doors but only to reduce the reflection, it’s not used for any serious absorption,

So if it isnt absorbing some frequencies but it is 'reducing' them as you say? Can I ask how it is reducing the sound reflection off your door?

I believe that all materials adsorb sound frequencies. How much and what frequencies the materials absorb depend on what your needs are. A tiny room of exposed Rockwool/fibreglass covered in fabric may be brilliant at sound absorption but not to every bodies liking.
 
What *is* with this unbased bias against (fear?) of fabric covered rockwool?

You'd rather be breathing bits of plastic that are not covered at all? Cotton fibers from mountains of old towels? (Our walk-in closet is, oh 100x, dustier than my music room with completely wrapped, wood framed, mounted Roxul panels - they are not ejecting fibers - I vacuum dust maybe a few times a year just because...)

It's not like I'm working in the mines here.
 
So if it isnt absorbing some frequencies but it is 'reducing' them as you say? Can I ask how it is reducing the sound reflection off your door?

I believe that all materials adsorb sound frequencies. How much and what frequencies the materials absorb depend on what your needs are. A tiny room of exposed Rockwool/fibreglass covered in fabric may be brilliant at sound absorption but not to every bodies liking.

I think witz is just pointing out that the foam might be useful for obvious higher frequency reflections (echo when you decorate a room), but not much use for a broader range of frequencies.
My knowledge is limited here but I think people mainly focus on absorption and/or diffusion.

Absorption; Sound wont (fully) travel through.
Diffusion; Reflections are scattered in different directions.

The more dense the material, the great the range of frequencies it will affect, in terms of absorption.

If you pop some light foam over your ears, you'll get a quick idea of what it does/doesn't absorb.
 
What *is* with this unbased bias against (fear?) of fabric covered rockwool?

You'd rather be breathing bits of plastic that are not covered at all? Cotton fibers from mountains of old towels? (Our walk-in closet is, oh 100x, dustier than my music room with completely wrapped, wood framed, mounted Roxul panels - they are not ejecting fibers - I vacuum dust maybe a few times a year just because...)

It's not like I'm working in the mines here.

Rockwool/fibreglass is made from sand or similar rock I believe. Both are a known lung irritant as well as skin in some people (me).

Cotton fibres I dont think could irritate the lungs but certainly block them up. Cotton does not irritate the skin. Not mine anyway.

Foam may give off vapors when new. Bad/ harmless??? Who knows?

Sheeps wool is as natural as you can get.........I couldn't stand it within 10 yards off me. It would drive me insane.

Horses for courses but of most of the videos I have seen on Rockwool/fibreglass panels they never pay much attention to the cloth being of a fine enough weave to keep the fibres in.........I just watch the wrong videos.

Each to their own. In a small booth I would prefer something like foam and other non irritant materials in such a confined space to absorb sound.
 
I thought the idea was to 'absorb'? As does any material to an extent depending how good it is at sound absorption.

correct, foam does absorb, but it only has a very limited frequency range, in music reproduction we want to have a balanced spectrum.
 
Rockwool/fibreglass is made from sand or similar rock I believe. Both are a known lung irritant as well as skin in some people (me).

Cotton fibres I dont think could irritate the lungs but certainly block them up. Cotton does not irritate the skin. Not mine anyway.

Foam may give off vapors when new. Bad/ harmless??? Who knows?

Sheeps wool is as natural as you can get.........I couldn't stand it within 10 yards off me. It would drive me insane.

Horses for courses but of most of the videos I have seen on Rockwool/fibreglass panels they never pay much attention to the cloth being of a fine enough weave to keep the fibres in.........I just watch the wrong videos.

Each to their own. In a small booth I would prefer something like foam and other non irritant materials in such a confined space to absorb sound.

rockwool is completely harmless, you are being really silly, it's protected by cotton fabric wrapped around it in a wooden frame, the fibres can't go anywhere! you can simply spray it with adhesive glue if it really bothers you. Rockwool has passed a lot of ridiculously high standard health and safety tests including EU tests and UK government tests, if was dangerous they'd have banned it before making it commercially available.
 
I thought it was an irritant?

I think too much of any dust things inside you is not a good thing whatever it may be.
 
The only time you could get fibers or particles from rockwool or fiberglass is when handling it. Once its in place, it is not going to keep 'spitting out' particles at you, and certainly not when wrapped in cloth.
Unless you live in a very southern climate in an older building, your house has fiberglass in all the outer walls.
 
So if it isnt absorbing some frequencies but it is 'reducing' them as you say? Can I ask how it is reducing the sound reflection off your door?

It's to reduce simple reflection off the door. I know about what you need to build to absorb High, Mid and Low frequencies, in fact the studio has this installed as it runs as a semi-pro studio, but the door was a large flat reflective surface and the simple way to reduce any slap back from the door was to use foam.

I am no fan of foam and I know it can't be sued as sound proofing and serious frequency control, but in this case it worked for what I needed.

Alan
 
A tiny room of exposed Rockwool/fibreglass covered in fabric may be brilliant at sound absorption but not to every bodies liking.

I wrapped all my fiberglass traps with a super thin layer of plastic drop-cloth...about as thin as plastic food wrap...which has no significant effect on audio passing through it, but guarantees that no glass fibers will ever get out...though it was probably overkill, since the fiberglass panels were aluminum/paper covered on one face and wood covered on the sides/tops...plus polyester felt covered on both faces...and finally acoustic cloth covered on both faces as the final layer.
Considering that these are very large/deep traps that are multi-use "mobile" and not permanently installed...I just wanted the extra insurance that the fiberglass would be sealed.
For permanent mounting on walls, I think fibers escaping is not a real concern. On ceilings....mmm....I think I would want to seal them.
 
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