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Are sound absorbers safe for our health?

youngho

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Thanks, I already have 5 basotect (melamine) panels Hofa in my living room. Works well. But an idea was to buy/build something 100% natural for a small office where I spend 10h per day
Ah, you didn't mention natural materials in the original post, just relatively safe ones. Even the wood-based ones like in https://link.springer.com/article/10.1007/s10570-021-03774-1 have synthetic components. Can consider sheep's wool products: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5706224/, one commercial vendor is https://www.woollyshepherd.co.uk/
 
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Yevhen

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What do you guys think of these panels: https://www.cewood.com/en
Probably they are least effective, but I saw them being used in every kindergarten and school in our city. Just wood and cement.
 

Inner Space

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If the fiberglass is sealed inside plastic wrap, doesn't that prevent it from absorbing acoustic energy as the sound cannot pass through it?
No, it works perfectly. The wrap reflects a little HF, which can sometimes be desirable, but LF passes through the wrap undisturbed and is absorbed inside.
 

MRC01

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No, it works perfectly. The wrap reflects a little HF, which can sometimes be desirable, but LF passes through the wrap undisturbed and is absorbed inside.
Consider a tube trap. Having some reflective wrap on the outside is useful as it can disperse some mid-high frequencies. But that wrap doesn't go all the way around the tube or seal it. So the low frequencies still pass through the fiberglass which converts some of the sound energy into heat.

If, however, the entire tube trap was wrapped in something airtight, it would be sealed. How would low frequency sound / pressure waves penetrate it to get absorbed by the fiberglass?

I suppose I could test this myself: seal my tube traps in saran wrap and measure the difference. That would take a lot of saran wrap, as they are 7' tall and 2' diameter.
 

Inner Space

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Consider a tube trap. Having some reflective wrap on the outside is useful as it can disperse some mid-high frequencies. But that wrap doesn't go all the way around the tube or seal it. So the low frequencies still pass through the fiberglass which converts some of the sound energy into heat.

If, however, the entire tube trap was wrapped in something airtight, it would be sealed. How would low frequency sound / pressure waves penetrate it to get absorbed by the fiberglass?
How do low frequency pressure waves pass through walls? If thin plastic was enough to stop them, then the world's soundproofing problems would be solved at a stroke. Believe me, LF penetrates micron-thick plastic wrap without even noticing. Many treatments are boxed behind 1/4" plywood sheets, etc. This really isn't an issue.

LF waves are powerful and penetrating. I worked a few stadium gigs once (only a few, because I hate working outside) and the gigantic sub arrays were always fenced off with crowd control barriers, because if you got too close, not only were you liable to instant hearing damage, but the sheer impact could stop your heart, or break your ribs. Not directly the same as a domestic situation, of course, but the same principle applies.

PS - you don't have to believe just me - I just found this on Ethan Winer's site (he's pretty reliable on this subject): "Another great and inexpensive way to make a bass trap - if you have a lot of room - is to place bales of rolled up fluffy fiberglass in the room corners. These bales are not expensive, and they can be stacked to fill very large spaces. Better still, they are commonly available and you don't even have to unpack them! Just leave the bales rolled up in their original plastic wrappers, and stuff them in and near the room corners wherever they'll fit. Stack them all the way up to the ceiling for the most absorption."
 

SIY

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I'm not sure of the worry about flame retardants unless you're a firefighter and expect the insulation to be ablaze. For open-cell polyurethane foam (an excellent absorber), the FR package is primarily TCPP (very low vapor pressure).
 

bo_knows

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I think those fiberglass absorbers are definitely no go for me, although it might be the cheapest and one of the most effective options.
This is what I used exclusively for my bass absorber panels. I was no longer comfortable with the fiberglass even though it was way easier to work with (especially the cutting part).

 

bo_knows

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The separation is not as solid as you might think. In crawl spaces and attics the fiberglass is often exposed. And you can get air movement through these spaces, especially on windy days. My point is that fiberglass is all around us: houses, sports equipment, cars, etc. Just because something has fiberglass in it doesn't automatically make it hazardous. It may or not be, depending on the situation.

I used a gloves & mask when handling raw fiberglass for my tube traps, but I don't feel that is necessary when handling them now, or when being in the room, as they are fully covered with 2 layers of fabric. Do enough fibers escape to cause a health hazard? I doubt it, they've been there for 10 years and I haven't noticed any dust or fibers when handling them or when cleaning the room. Nobody has been coughing or sneezing. Since they're wrapped, I don't worry about it. Just my experience, anecdotes are not evidence, etc.

That said, I would not have an acoustic treatment with exposed fiberglass in my room. Even if the exposed fiberglass were inside, I'd want it covered to prevent migration of flakes/dust.

PS: let's not restrict this solely to acoustic treatments. I've seen speakers with fiberglass inside that are ported. Due to the driver motion you can feel the air pumping in and out of the port...
What about formaldehyde odor?
 

Inner Space

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I suppose I could test this myself: seal my tube traps in saran wrap and measure the difference. That would take a lot of saran wrap, as they are 7' tall and 2' diameter.
Or alternatively you could wrap your speakers - a couple of layers over the woofers. According to your intuition, you should hear no bass in your room at all.
 

MRC01

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Or alternatively you could wrap your speakers - a couple of layers over the woofers. According to your intuition, you should hear no bass in your room at all.
No, what I'm saying is if you sealed them airtight it seems like you'd measure some bass attenuation. The analogy to room treatments is it would make them less effective. The big question is: how much attenuation? I don't know.
 

MRC01

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What about formaldehyde odor?
The raw fiberglass had a chemical odor when I first opened it. Don't know whether it was formaldehyde, or something else. They were in my garage workshop for about a week while I was constructing them. It's well ventilated. By the time I was done, the odor was gone.
 

earlevel

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Absorbers often contain fiberglass, which can shed stray fibers that damage skin, eyes, lungs. I used gloves and a mask when handling the fiberglass and constructing my tube traps. But the fiberglass is typically inside the device wrapped with cloth or similar coverings that would trap most of any stray fibers that come loose. As least in my case it is.
Just some comments (not necessarily to you, but the board):

First...funny memory, the first surfboard I made, I started with an old longboard and filed the edges and pealed off the resined fiberglass to use the foam core—my arms itched for few days from that lesson. The concern is that when you work with fiberglass, tiny pieces can break off and you can inhale them. There's the intuition that the glass is not going anywhere once lodged in your lungs, but it ends up that your lungs clear it pretty easily (unlike asbestos, for example).

But, the only decent chance of this happening is while working with the material, cutting (probably #1), flexing, or crushing it. When it's covered and hung on the wall, there isn't much opportunity. Also, I've read the argument that other materials like cotton and rock wool are actually much harder for your lungs to expel. I don't know, but the argument was convincing enough to consider.

Fiberglass is considered a potential threat, that is sure. But consider that some people work with fiberglass insulation day in and day out in concentrations no one in a studio will be subjected to, and it's still not a slam dunk that it's a major health threat, despite research. If you're making your own panels, it's prudent to wear a mask, make them outdoors or in the garage. After you've covered and hung the panels, it's unlikely they are any threat. Probably similar to worrying about outgassing from plastics in your studio.

Just giving the flip side—I was considered making panels a while back, and got concerned about fiberglass after someone mentioned it, was going to go with rock wool, but after reading more I would just go with Corning 703. Those panels require very little handling anyway, they come in the right size.
 

Glen20

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Thanks for the info SIY
Personally I was concerned,due to the fact that I would get a significant amount of black dust on the floor around my ( we’ll know brand )bass traps.
On the other hand we did have 11000 felt and potentially damaging earthquakes in 2.5yrs. ( and unfortunately 185 deaths)
I seem to get less dust now.
I'm not sure of the worry about flame retardants unless you're a firefighter and expect the insulation to be ablaze. For open-cell polyurethane foam (an excellent absorber), the FR package is primarily TCPP (very low vapor pressure).
I'm not sure of the worry about flame retardants unless you're a firefighter and expect the insulation to be ablaze. For open-cell polyurethane foam (an excellent absorber), the FR package is primarily TCPP (very low vapor pressure).
 

caught gesture

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If the fiberglass is sealed inside plastic wrap, doesn't that prevent it from absorbing acoustic energy as the sound cannot pass through it?
I thought that in order to function properly, they need to be wrapped in something that is relatively transparent to air movement, yet retains any fibers that the fiberglass might shed. Typical fabric type coverings.
Low frequency sound waves will pass through a plastic wrap. High frequency content will be reflected. That is why your neighbour will complain about the bass from your system but not the treble!
 
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gene_stl

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I have done a lot of microscope repairing. Scopes that had kits of gear with them back in the day often had open cell foam for padding. Because of the open cell structure the material was attacked by atmospheric oxygen. This invariably results in a big mess for someone to clean up.

One of the atmospheric moieties that does the attacking is ozone which is not widely present but is very high on the chemical reactivity scale.
Over the years ozone produced by weather, sunlight and electrical equipment and lights turns open cell foams into goo.

A very easy google search will bring up zillions of hits regarding a recall of Phillips Respironics CPAP and other ventilatory support machines.
They push they air through open cell foam and people started sanitizing them with ozone , which essentially burns bacteria and viruses. It also degrades the PE-PU black foam which started shedding black particles into the breathing circuit.

They have also discovered that these foams outgas when new. Most users are not bothered as the concentration is not terribly high but they have quoted a complaint rate of 0.03% Since people have to self report this is likely to be a bit low. As the volatiles blow off the outgassing stops reportedly in about a month of use. There are some people who are more sensitive and reactive than others or most people.

After cleaning up lots of microscope boxes messed up with icky sticky goo I hate this material. When I see it I usually remove it before it starts to deteriorate. Consequently I would never use or knowingly buy anything that had a large quantity of this material in it even though a bass trap isn't a CPAP machine.


Foams have zillions of compositions and some are more durable and resistant than others.
 
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ZööZ

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I'm using fiberglass acoustic panels and sure the setting up part is more laborous and annoying with masks and gloves but after they're on the wall/ceiling there shouldn't be any health risks unless they are damaged and shedding large quantities of fiber dus.
Glass fibers are nothing like asbestos or such as the fibers "pass" through your system in a relatively short period of time... We're talking tens of days tops and they haven't been found to cause cancer.
Went with glassfiber panels because they were cheaper and the absorption graph seemed to go to lower frequencies than the alternatives I was looking at. But sure they are a bit inconvenient in a linvingroom setup as I'll have to be careful not to touch them to avoid itching and breaking them.
 
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Yevhen

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This is what I used exclusively for my bass absorber panels. I was no longer comfortable with the fiberglass even though it was way easier to work with (especially the cutting part).

Thanks, I have tried similar ones from a local supplier, but thomey also contain fire detergents, so probably the same thing as melamine or even worse
 
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