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DIY acoustic panels with rockwool and a fan

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DIY acoustic panels with rockwool and a fan

Postby Guitarking » Sat Jun 13, 2020 7:23 pm

Hi everyone,
I want to hang a ceiling fan on my diy cloud which basically is a wooden frame with rockwool in it covered with a thin fabric to (hopefully) prevent the fibers from getting all over my room.
Would engaging the fan release the fibers of the rockwool? Is it dangerous? I made all my acoustic panels (e.g. basstraps) like that, and I made me think: maybe my studio is dangerous because of all the rockwool (covered in a thin layer of fabric)?
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Re: DIY acoustic panels with rockwool and a fan

Postby Hugh Robjohns » Sat Jun 13, 2020 7:54 pm

I'm not aware of anyone in the professional studio or broadcast industries ever dying of Rockwool poisoning.

Assuming your covering fabric has a reasonably tight weave there shouldn't be any risk of mineral wool fibres escaping.

As for suspending a ceiling fan from the cloud, I'd be concerned of (a) headroom and (b) the cloud frame/structure acting as a soundboard. A cloud high enough to support a fan would need to be proportionately larger than your average cloud...
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Re: DIY acoustic panels with rockwool and a fan

Postby Guitarking » Sat Jun 13, 2020 9:06 pm

Thanks Hugh,

It's just a mini caravan ceiling fan so not heavy at all

At the time I choose a fabric that was pretty thin, hopefully thin enough to let air through but thick enough to stop the fibers. I find it hard to judge where the balance is. The panels have been in my studio for 10 years and I have never noticed any problems with fibers. I just hope the air caused by the mini-fan will not 'waken' the fibers ;-)

Do you mean you're afraid the fan might act as a reflection?
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Re: DIY acoustic panels with rockwool and a fan

Postby Sam Spoons » Sat Jun 13, 2020 9:14 pm

Rockwool (the company) claim there is no danger from rockwool (the material) fibres and there is no evidence I have found to suggest they are wrong. Rockwool certainly sheds fibres when you cut it but I too have had a fair number of panels in my small home studio and have not noticed anything identifiable as RW fibres on surfaces or in the vac.
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Re: DIY acoustic panels with rockwool and a fan

Postby Nyiregyhazi » Sun Jun 14, 2020 1:44 am

I'd consider taking extra measures. I put most of mine in clingfilm before covering in fabric. Apparently this shouldn't effect the absorbency of anything but high pitches, and the material should be enough to compensate for that anyway. The ones I added more recently just went in duvet covers, which I just glued after folding the excess material. However, I might be a bit more worried about having it close to a fan.

I know rockwool is unlikely to be lethal, but around the time when I got the first batch in I went through a spell of having very strong tinnitus and being very sensitive to noise. Even when I was teaching on an upright piano it felt uncomfortable and I had to cover up my grand piano for a few weeks before I was comfortable with the normal level again. It could just be coincidence, but I always suspected it might have been something to do with loose fibres getting into my system.
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Re: DIY acoustic panels with rockwool and a fan

Postby Sam Spoons » Sun Jun 14, 2020 10:16 am

I don't know how far down the frequency spectrum making the surface of the rockwool impermeable would have an affect but it certainly will have an effect. Rockwoll traps work by allowing the sound waves to pass through the porous material and even the dressing on the surface compromises performance to some extent (bass traps made from chunks laid horizontally are more effective as the cut edges have no surface treatment). Covering them in clingfilm will certainly make them impermeable and reduce their effectiveness.

If fibres are going to have any affect I'd expect it to be respiratory, I'm pretty sure the fibres are too big to be absorbed into the bloodstream (I've certainly never read anything that suggests they might be) and I have never heard of anything similar being a cause of tinnitus or hyperacusis. Sensible precautions when handling rockwool is clearly a good idea, even if only to help avoid the itchiness they can cause* but there are enough rockwool panels in use around the world that issues would almost certainly have come to light by now.

* Over the years I have handled several different materials like glass fibre (both thermal insulation and as a material for fabricating/repairing boats and cars) carbon fibre and, obviously, rockwool. Fibreglass and CF are pretty bad for causing skin irritation, especially when sanding, RW less so and natural fibre pretty much not at all.
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Re: DIY acoustic panels with rockwool and a fan

Postby Hugh Robjohns » Sun Jun 14, 2020 11:23 am

Nyiregyhazi wrote:...around the time when I got the first batch in I went through a spell of having very strong tinnitus and being very sensitive to noise.

I'd have thought it more likely that it was either a coincidence, or that you were working with power tools during the installation that triggered your tinnitus. Or, simply that the quieter room made the pre-existing tinnitus more obvious.
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Re: DIY acoustic panels with rockwool and a fan

Postby Nyiregyhazi » Sun Jun 14, 2020 6:00 pm

As I say, I don't know for sure that it was the rockwool. I didn't use any power tools. Another possibility is cbd oil, that I've been using for inflammation. There are both reports of people having it improve and aggravate their tinnitus. I've been keeping to lower doses and using more locally, on the bone where I have swelling issues. However, it definitely wasn't just subjective. Hearing a mere upright piano in a much larger room felt painful at the time. While I still have varying degrees of tinnitus, I don't have the sense of the piano sounding painful to listen to.

Regarding the clingfilm, I saw some threads in which people had some graphs suggesting it wouldn't make a notably big difference, I believe, although I forget where. I remember quite a logical suggestion of covering the ears in clingfilm and seeing how much it affects hearing, to give an idea of how much will pass through. It's not a truly spectacular reflecter of sound, even though it will be a partial issue.
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Re: DIY acoustic panels with rockwool and a fan

Postby Hugh Robjohns » Sun Jun 14, 2020 6:09 pm

Nyiregyhazi wrote:However, it definitely wasn't just subjective. Hearing a mere upright piano in a much larger room felt painful at the time.

Fair enough. Infection? Ear wax? Blocked Eustachion tube...Lots of benign things can cause temporary changes to hearing. My hearing is completely messed up for days after a long flight due to the pressure changes and how that affects my ear drums.

Regarding the clingfilm, I saw some threads in which people had some graphs suggesting it wouldn't make a notably big difference.

It certainly won't make significant difference at low and low mid frequencies. I'm not so sure about higher frequencies though... I imagine any tension it's under will make a difference too.

Obviously the requirement is for the clingfilm membrane to move in response to arriving sound waves, causing a sympathetic movement of air within the enclosed rockwool which will absorb the acoustic energy. There will come a point where the acoustic sound waves are no longer able to move the clingfilm...
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Re: DIY acoustic panels with rockwool and a fan

Postby Sam Spoons » Sun Jun 14, 2020 6:14 pm

Nyiregyhazi wrote:Regarding the clingfilm, I saw some threads in which people had some graphs suggesting it wouldn't make a notably big difference, I believe, although I forget where. I remember quite a logical suggestion of covering the ears in clingfilm and seeing how much it affects hearing, to give an idea of how much will pass through. It's not a truly spectacular reflecter of sound, even though it will be a partial issue.

Thinking about this from first principles, I think the effect of covering the rockwool with clingfilm will be somewhat different to covering your ears. The rockwool works as an absorber because the moving air molecules pass into the matrix of fibres which then slow the movement down, turning the energy into heat. By preventing the air molecules from passing into the rockwool you are removing much of it's ability to do this. A very thin drum membrane over your ear will vibrate and transmit the vibrations in the outside air to the air in your ear canal with very little change but it is a very different principle*.

WRT tinnitus, I am a sufferer and also have sinus issues. My tinnitus gets worse as I have more earwax (sorry, lovely conversation.....) and when my sinuses are blocked. Clearing the wax helps reduce the tinnitus so I would concur with Hugh's suggestion that in your case it is unrelated to rockwool exposure based on my own experience.

* The clingfilm wrapping the rockwool can't vibrate and thus can't transfer the sound energy into the air in the rockwool matrix.
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Re: DIY acoustic panels with rockwool and a fan

Postby Hugh Robjohns » Sun Jun 14, 2020 7:48 pm

Sam Spoons wrote:By preventing the air molecules from passing into the rockwool you are removing much of it's ability to do this. A very thin drum membrane over your ear will vibrate and transmit the vibrations in the outside air to the air in your ear canal with very little change but it is a very different principle*... * The clingfilm wrapping the rockwool can't vibrate and thus can't transfer the sound energy into the air in the rockwool matrix.

I believe the cling film will be free enough to vibrate and pass the sound wave on because the surface it is lying upon is not itself flat, and the cling film is not under high tension. But the transmission will probably be frequency dependent.
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Re: DIY acoustic panels with rockwool and a fan

Postby Nyiregyhazi » Sun Jun 14, 2020 9:21 pm

It seems to me that there's no obvious reason why the clingfilm wouldn't be agitated and pass that on to the air inside. I think the only way to fully clear up something like this would be in practise rather than in theory though. It would need empirical testing of before and after.

Either way, are people really using rockwool as an urgent part of cleaning up higher frequency? It's not exactly the hardest part of the range to catch. Even if clingfilm were theoretically to nullify the rockwool altogether, surely the material alone would be doing a reasonable amount for the lower energy high frequency waves? It would be pretty dumb if someone did the same to some foam (to risk covering the only range it can actually serve) but I wouldn't have thought that anyone with a large amount of fabric covered rock wool would be especially in danger of missing the top end, surely?
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Re: DIY acoustic panels with rockwool and a fan

Postby Nyiregyhazi » Sun Jun 14, 2020 9:25 pm

Sam Spoons wrote:
Nyiregyhazi wrote:Regarding the clingfilm, I saw some threads in which people had some graphs suggesting it wouldn't make a notably big difference, I believe, although I forget where. I remember quite a logical suggestion of covering the ears in clingfilm and seeing how much it affects hearing, to give an idea of how much will pass through. It's not a truly spectacular reflecter of sound, even though it will be a partial issue.

Thinking about this from first principles, I think the effect of covering the rockwool with clingfilm will be somewhat different to covering your ears. The rockwool works as an absorber because the moving air molecules pass into the matrix of fibres which then slow the movement down, turning the energy into heat. By preventing the air molecules from passing into the rockwool you are removing much of it's ability to do this. A very thin drum membrane over your ear will vibrate and transmit the vibrations in the outside air to the air in your ear canal with very little change but it is a very different principle*.

WRT tinnitus, I am a sufferer and also have sinus issues. My tinnitus gets worse as I have more earwax (sorry, lovely conversation.....) and when my sinuses are blocked. Clearing the wax helps reduce the tinnitus so I would concur with Hugh's suggestion that in your case it is unrelated to rockwool exposure based on my own experience.

You don't think inhaling the fibres could affect the sinuses? The ear, nose and throat are very closely connected. I can't say it was a definite cause, but it seems perfectly logical to see the potential possibility.
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Re: DIY acoustic panels with rockwool and a fan

Postby Sam Spoons » Mon Jun 15, 2020 11:34 am

Yes, clearly inhaling fibres will affect the sinuses and lungs. But in my case the timing doesn't add up, my underlying sinus issues are a constant over many years, if it was related to working with rockwool or other skin irritant materials I would expect it to improve during the long periods between such work and that is not the case.

I can't see how it would affect earwax production, and if it did the same would apply.

In both cases a trigger for increased wax production and the sinus issue worsening has been prolonged use of custom IEMs or earplugs.

WRT acoustic panels, I have always believed that to be effective any covering placed over the rockwool needs to me acoustically as transparent as possible and the crude test for this is how much, or little, it impedes breath. Clearly clingfilm will impede breath very effectively.
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Re: DIY acoustic panels with rockwool and a fan

Postby Nyiregyhazi » Mon Jun 15, 2020 4:10 pm

This is the thread where someone posted a graph suggesting next to no difference.


https://www.gearslutz.com/board/bass-tr ... astic.html
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