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Tasteful rigid fiberglass room treatment panels

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Epos7

Epos7

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2" panels do not make very good broadband absorbers, 6 to 8 inches with an air gap behind makes a much better absorber that is less frequency selective.

Thanks fluid, that rings a bell as I believe I read some of Toole's work when I originally bought the fiberglass. I'll need to figure out which version of Owens Corning I have, as I imagine the density will affect how thick the absorbers need to be. I think I have Owens Corning 703, which is 3 pcf, but I will need to double check that. 6" absorbers would be doable. I originally built them up to 4" thick by stacking the panels, but I have plenty so could easily do 6". I think if I were to do 6" I'd want to try to integrate a stand so they could stand on their own away from the wall.
 
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Epos7

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Well I misremembered as it's not Owens Corning at all - it's manufactured by Johns Manville. For all intents and purposes, it looks exactly the same however. I think I have either 27 or 36 of these 2" boards.

20210918_120523.jpg


Here's the burlap I used for my first version of the panels. My 17 year old self rather liked the burgundy, but I think this time around I'll go for something more neutral like cream or grey ;)

20210918_120337.jpg
 
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Epos7

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I'm thinking the most practical way to build new absorbers may be to integrate them into some furniture. Corner shelving unit with a 6" absorber on one side might be cool. The shelves could create the necessary spacing away from the wall.
 

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I've been working on this project here. Just now I wrapped one of my panels:


I'm using the GIK "Standard" fabric, which is like a slightly open weave muslin. I was going to use a microsuede fabric from another supplier but the literature which came with their samples mentioned that it was less acoustically transparent than other fabrics. Sort of defeats the purpose! I suspect the same goes for the printed art panels.


I'm using the tan color. It looks good against the sage/light french gray/white walls I've put it next to.
 
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Epos7

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View attachment 155969

Here's the first panel I wrapped.

Looks great! I like the neutral color. I have some fabric samples on the way from GIK and some from Acoustimac.

I'm also curious about some fabric from Guilford of Maine called Whisper. From what I understand their FR701 isn't as transparent as other fabrics, although nobody ever seems to specify what those other fabrics are. Regardless, the Whisper looks to perform a bit better than FR701:

1632783745598.png
1632783785678.png
 

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Looks great! I like the neutral color. I have some fabric samples on the way from GIK and some from Acoustimac.

I'm also curious about some fabric from Guilford of Maine called Whisper. From what I understand their FR701 isn't as transparent as other fabrics, although nobody ever seems to specify what those other fabrics are. Regardless, the Whisper looks to perform a bit better than FR701:

View attachment 155973View attachment 155974

I didn't see any data for the fabric I ordered. My strategy is to just build a hell of a lot of panels.
I suspect the very cheap burlap sold by GIK or ATS (many colors) is probably the best from an acoustic standpoint.

I used to work in interior architecture and I never once saw pre-occupancy verification of acoustic treatments such as panels or glass partition systems. One time a designer asked to use my SPL meter but I'm not sure what she hoped to accomplish without a broadband noise source. My point is that I don't think many people are super serious about the performance of these fabrics, which is dissapointing, because it should be relatively easy to measure them (compared to NRC values or STC values).
 

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I was going to use a microsuede fabric from another supplier but the literature which came with their samples mentioned that it was less acoustically transparent than other fabrics. Sort of defeats the purpose! I suspect the same goes for the printed art panels.
Great work - congratulations. But if I may - the fabric doesn't need to be acoustically transparent. All it needs to be is not reflective at higher frequencies. "Not acoustically transparent" means it absorbs some of the energy as it passes through - which is a good thing for a panel covering.
 

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Great work - congratulations. But if I may - the fabric doesn't need to be acoustically transparent. All it needs to be is not reflective at higher frequencies. "Not acoustically transparent" means it absorbs some of the energy as it passes through - which is a good thing for a panel covering.
I guess that makes sense!

Developing an intuition about sound is not easy so comments like these are always welcome..
 
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All it needs to be is not reflective at higher frequencies. "Not acoustically transparent" means it absorbs some of the energy as it passes through - which is a good thing for a panel covering.

That's a good clarification. I've also been referring to ideal fabric as being acoustically transparent, though as you noted for panel use it just needs to not reflect. Trouble is some fabrics do seem to reflect higher frequencies when installed on panels, like FR701.
 

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on a sidenote, reflective fabric can be beneficial for panels outside of the direct path first reflection points. the room will be less dead

That's a good point. Just goes to illustrate how complex room acoustics is. I strongly suspect that for a listening room, diffusion is more important than dampening.

One nice thing about diffusion is that it doesn't change the tonal balance of the reverberant field, but we are seeing fairly complex EQ in dampening materials. Obviously there is the issue that they don't absorb bass efficiently (in most installations) but then on top of that you have the variable reflection of HF.
 
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