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Post by charlie on May 4, 2018 12:47:35 GMT
Hi,
I'm pretty sure it has been asked before, but I can't find it anywhere so forgive me for asking once more..
Let's say we have some huge corner traps, floor to ceiling, made of 703, pink fluffy or whatever material.
We are said to put in front a layer of FRK or 1mm plastic membrane to reflect mid-high frequencies, plus a fabric coverage for aesthetic.
What if a thin plywood panel is put in place instead ? Let's say 3mm plywood, or faced panel.
It can be bent by fixing it at the vertical sides, thus creating a huge quarter column. It can be aesthetically pleasant, without dealing with sagging fabric and so.
Would it block the absorption at low frequencies ? Or is it a cost issue only ?
thanks!
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Post by charlie on May 4, 2018 13:00:19 GMT
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Post by Hexspa on May 4, 2018 17:50:20 GMT
Your wood might help with some low frequencies but it's not going to help absorb mids and highs. The main thing is that it needs to be in contact with the absorbent material. If you don't have extensive experience, training, or mentorship then keep it simple and use FRK.
He's covered resonant absorbers with drywall. Those aren't superchunks. I don't know about that kind of treatment so maybe someone else can comment.
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Post by rock on May 4, 2018 19:26:13 GMT
Charlie,
Regarding your question about using thin plywood over porous absorbers, I really don't know for sure but I would imagine the plywood would reflect a significant amount of LF thereby reducing the effectiveness of your traps. The paper or plastic (and BTW, the plastic is about 1 mil which is one thousandth of an inch NOT 1 millimeter or 39 mils thick!) is much less stiff and will allow LF to pass into the FG. That's my thinking anyway.
As far as sagging fabric goes, I have not had a problem getting fabric to stretch nice and smooth. I've used burlap and speaker grille cloth. In a permanent installation, I'v used wood framing around the perimeter for stapling the fabric. To hide the staples and fabric edge, cover with finish moulding. If you stain&varnish or paint the moulding, do it before you nail it up. To make it look right, you'll have to rip bevels into your frame and molding...best done on a table saw.
Hexspa is right and Helmholtz resonators are a completely different animal. You should ask the guy in the video. It looks like he's expecting a single port on each unit to be enough...I don't know but I gotta wonder if that's enough but like I said, I don't know either.
Getting back to the plywood idea, if you really want to find out, you can duplicate Ethans test with an empty room first , then fill it with plain FG panels then FRK and finally FG with plywood. Take measurements each time. I'm sure we'd love to see the results.
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Post by Charles on May 4, 2018 20:45:38 GMT
Thanks a lot Hexspa and Rock.
My new apartment is under full renovation, where I'll have a dedicated music room.
I''m eager to start with measuring and fiddling with acoustic treatment, later this year.
Of course I'll share my findings.
About the thin plywood cover, maybe a good compromise could be a slotted or perforated panel, as seen on some commercial traps.
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Post by Hexspa on May 5, 2018 0:18:29 GMT
Thanks a lot Hexspa and Rock. My new apartment is under full renovation, where I'll have a dedicated music room. I''m eager to start with measuring and fiddling with acoustic treatment, later this year. Of course I'll share my findings. About the thin plywood cover, maybe a good compromise could be a slotted or perforated panel, as seen on some commercial traps. There exist many specialized acoustically transparent materials. I remember reading about such a kind of plaster. You can definitely do some cool things. In the spirit of simplicity, we generally agree that broadband treatment should be your first port of call. You definitely don't want to drywall over that. I've seen some amazing fabric coverings in permanent installations, like rock stated. If Ethan was a tshirt, it'd say "More Bass Traps". If I was one it'd say, "Keep It Simple". If rock was a garment, it's text would say, "You Are All Idiots". jk rock |
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Post by rock on May 5, 2018 3:14:20 GMT
Ethan's a T and I get to be a garment? Right, garment is kinda generic, but I could be a silk shirt? No?... I'll take that as an un-deserved compliment but thanks all the same! I think you should let Ethan be the Silk Shirt and I'll be the worn T shirt with holes in the arm pits (like the one I'm wearing). Well alright then.
But my shirt might say "You do it Your way...and I'll do it the Right Way" OR "Those of you who think you know everything are annoying to those of us who do."
"What have we become?" Ha Ha?
But in all seriousness, stick with the porous absorbers. Ethan's advice is so simple, it sounds like it won't work...but it does. Hexspa's advice just makes sense.
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Post by Ethan Winer on May 7, 2018 15:57:59 GMT
I can confirm that putting even thin plywood in front of a bass trap is a Bad Idea, and adding drywall is even worse.
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