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Post by mrfye17 on Jan 5, 2020 7:46:09 GMT
Hi People,
I have a room 11' 6" x 18' and have already installed Sofits (17" x 17") Floor to Ceiling on all 4 corners as well as Wall / Ceiling corners.
Side panels 2' x 4' x 6' deep with Roxul Safe'n'Sound for RFZ are done and will be putting up a ceiling cloud with same type of Panels.
I will be using these 2' x 4' x 6" deep panels also for the Back Wall.
My Question is....
How much of an Air Gap shall I allow between the Back Wall and the Panels for most effectiveness? 4", 6" or more?
Thank you to everyone in advance.
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Post by Hexspa on Jan 5, 2020 8:14:11 GMT
1x is standard but measuring and analysis will help you determine the ideal placements.
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Post by mrfye17 on Jan 5, 2020 20:19:42 GMT
Thanks Hexspa. Yes, I will measure and analyze but wanted to get the Best starting Spot. My room Sucks in the Low End.
So, you're saying, for better performance, that a 6" Air Gap is better than 4" which is better than no gap?
No need for more than 6"?
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Post by Hexspa on Jan 6, 2020 2:24:31 GMT
I'm saying that, in general, 1x is the best place to start but that may change based on the peculiarities of your room. So, in other words, you may use less or more or even choose to angle the panels to achieve the best result.
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Post by rock on Jan 6, 2020 3:49:19 GMT
mrfye17 Here's something that explains the gap from Ethan's pages as you may have missed it: ethanwiner.com/acoustics.htmlFor a given thickness of absorbent material, the ideal air gap is equal to that thickness because it avoids a hole in the range of frequencies absorbed. For example, if you install fiberglass that is four inches thick with a four-inch gap, higher frequencies whose 1/4 wavelength falls within the four-inch material thickness are absorbed regardless of the gap. And for those frequencies whose 1/4 wavelength is between four and eight inches, the fiberglass is also at the proper distance from the wall or ceiling. This is shown below in Figure 6. Top Response with an air gap Figure 6: The higher frequencies (top) are absorbed well because their velocity peaks fall within the material thickness. The lower frequency at the bottom does not achieve as much velocity so it's absorbed less. In practice, you don't necessarily have to measure wavelengths and calculate air gaps, and the first few inches of space yield the most benefit. Most people are not willing to give up two or more feet all around the room anyway, so just make the gap as large as you can justify. If you can afford to fill the gap entirely with material, all the better. And even though the velocity is indeed highest at 1/4 wavelength, there's still plenty at 1/8th of the wavelength too. Note that the angle at which sound waves strike a fiberglass panel can make the panel and its air gap appear thicker than they really are. Further, low frequency waves that strike an absorbing panel at an angle may be absorbed less than when they strike it at 90 degrees, due to a "grazing" effect. The explanations in this section are a simplification and are correct only for a 90 degree angle of incidence, which is not always the case.
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Post by mrfye17 on Jan 6, 2020 4:08:14 GMT
Aha! Didn't think about an angled experiment....
Thanks so much for your valuable help Hexpa...You've given me some direction. I think I'll be good now (one hopes!)
Also thanks to Rock for pointing to Ethan's analysis.
Cheers boys
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Post by eddiespaghetti on Jan 7, 2020 1:55:00 GMT
I'm saying that, in general, 1x is the best place to start but that may change based on the peculiarities of your room. So, in other words, you may use less or more or even choose to angle the panels to achieve the best result. Hmm, I'm sure I read somewhere Ethan saying you should not angle acoustic panels to divert reflections. Maybe he can chime in? I could be wrong, but I'm pretty sure I'm not.
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Post by Hexspa on Jan 7, 2020 2:56:23 GMT
It's not about diverting reflections but about the panel having a varied effect across the spectrum. Instead of your panel being on one plane parallel to the wall, gap or not, you're distributing its effect. I discovered this for myself by accident and confirmed it with measurements - at least it is better for my room.
That being said, while you might not use absorbers to divert reflections - indeed, they are incident-dependent - you can use reflectors for that purpose; particularly in large rooms, for specific recording purposes & sound-control structures like the concrete walls you see near highways.
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