Hi.
FYI, I gathered my information, primarily from Ethan Winer's "Acoustics" Website.
Ok, I know Ethan, and he knows me.
We've had many conversations over the years. And I've observed his "debates" with other colleagues over the years, including this subject with Eric Desart. In reality, I defended Ethan from viscious verbal attacks at the height of the anti-Ethan period.
If I remember correctly, the concept is similar to opening a window.
Yes, I am familiar with the concept. 1sq' of Perfect absorber = 1sq' of open window=1 Sabine
If you open a window half way, the window glass that remains open blocks a portion of the air flow.
Hmmm. I'll have to think about that one for a minute.
In this case it would be the wood/MDF sides blocking sound waves from passing through those covered portions of the "OC703" panel thus reducing the effectiveness.
That's odd. I never said it didn't. I asked where you got the information regarding "up to 33%". However, this all has to do with the "EDGE EFFECT" causing absorption coefficients of over 1, no?
Now, I'm certainly no expert, and please don't quote me on this,. but you might be interested. If I remember right, Eric did TWO tests on some panels of 703, whereby they were laid out on the floor of a lab in a checkerboard fashion, according to a certain Test Standard. In the first test, the panels were layed out in such a way as the edges were exposed, and yes, the results proved the absorption coefficient was more than 1. However, in the second test, the panels were FLUSH mounted within a framework that acted as a wall, and they STILL had an absorption coefficient of over 1. Since Eric is an acoustician, he hypothesized that absorption impedance differences(or something to that effect) were indeed the cause, as there were NO edges exposed to account for this extra absorption. So...in that light, at that time, I kind of stopped following the debate any further. If Ethan/others went on, and proved/disproved various arguments...so be it, as frankly, I didn't give a fuck....UNTILL I saw your statement. I was only trying to find out where you got the 33% thing. THAT's ALL!
As far as thickness is concerned, it's all relative.
ummm, IF, the "edge effect" is indeed due to exposed edge absorption...then on the contrary, thickness has a profound influence in comparison to the square footage of the front and back. ie, unless I'm missing something....IF, a 12"x12"x1" panel = X absorption coefficient in a given band, then a panel 12"x12"x6" "should" show an increase, no? Please explain if my assumption is incorrect. And please understand, I am NOT trying to debate this one way or the other. I haven't got the expertise, time, energy..etc..besides, it's already been done. I just wanna come up to speed, so to speak. And if you know the latest poop in this regard, I'd be delighted to hear it.
Also, when soundwaves pass through a backless acoustic panel, hit the wall and disperse throughout the room in differing directions, the frame covered portions of the acoustic panel will stop any reflected sound waves from entering through the "OC703" for a second pass, as it were, thus, again, limiting the effectiveness of "heat reduction" that occurs.
ummm, would you care to clarify that last bit. A reflected wave propagation BACK through the panel ..LIMITS the effectiveness...of heat reduction????? I was under the impression that the "interstices", as Everest called them, of the fibers were EXACTLY what causes "resistance" to gas flow, which in turn, results in an energy transform, which in turn, results in "absorption" of air molecular movement..OR SOMETHING TO THAT EFFECT.
And the process is no different whether it's a direct wave or a reflected wave...no?
So, ummm, now I'm a little confused by your statement.
If you block portions of the acoustic panel no matter how thin or thick, you are stopping soundwaves from passing through it, period.
Your absolutism is questionable. What happens when a 11ft long wavelength meets a 4" wide obstruction?
I seem to think it doesn't give a damn.
If you'd like to peruse Ethan's site to find the specific as to his concepts as to how blocking off portions of an acoustic panel would reduce it's efficiency and effectiveness, I'm sure he would be honored to have someone like you taking interest in his expertise.
Honored??? Shit, Ethan knows me and knows my PROFESSIONAL expertise in acoustics is ZILCH...ZERO...NADA!! That's why he can ignore me and roll his eyes at will.
Acoustics for me is simply about learning, and like everyone else at HR, I'm just a recording "enthusiast" who happens to know enough about acoustics to make a fool of myself once in a while.
But still, I have to ask questions. In that regard, I wasn't confronting you...on the contrary..I was trying to LEARN from you.
(Of course, I'm not an acoustic engineer but I was fortunate to spend some extensive time with the the people at sE Electronics learning about the testing and acoustic principles of their "Pro" Reflexion Filter when it was first released then soon after spending time learning acoustic principles with Ethan Winer after the release of his "Real Traps" "Portable Vocal Booth". In fact, I found myself in the middle between both companies for a time during some good-natured competitive "ours is better" "no OURS is better" bantering. Thus, I'm not an expert, I just have enough knowledge to be dangerous, usually to myself more than anyone else.
Well crap...that's more than I can say.
More power to ya!
And btw, in reality, this is fitZ, if that means anything. Although, I bet there's a few here that'll have something to say about it, and it won't be nice.
Oh well. I'm here, like it or not.
Anyway, have a great day.
