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RPG says "Well balanced acoustical designs contain an appropriate combination of absorption, reflection, and diffusion." For use in my dedicated HT under construction, I'd like to consider some diffusion for the rear wall. But RPG's Hemiffusor and Skyline are about 4" deep and are challenging to fit into my smallish 2000 cu ft HT.


RPG also makes a Flatffusor. It looks like a flat plate with thousands of carefully placed holes that look sort of random. It's 1" or less thick and fits between the GOM and 1" rigid fiberglass. I assume it works, but does anyone have experience with it? Doesn't the additonal rigid fiberglass on the rear wall deaden the room even more?


The Flatffusor doesn't seem to diffuse as well as the Hemiffusor, but it's installation is certainly easy. I assume some diffusion is better than none.


RPG's literature is confusing in that it doesn't indicate to me that the diffusor covers all the audio frequency spectrum. It says it "provides uniform sound diffusion at high and mid band frequencies and crosses over to pure absorption below the difffusive cutoff." What frequency is the cutoff? Is diffusion preferred across the entire audio spectrum?

Take Aim
 

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Quote:
Originally Posted by takeaim
RPG says "Well balanced acoustical designs contain an appropriate combination of absorption, reflection, and diffusion." For use in my dedicated HT under construction, I'd like to consider some diffusion for the rear wall. But RPG's Hemiffusor and Skyline are about 4" deep and are challenging to fit into my smallish 2000 cu ft HT.


RPG also makes a Flatffusor. It looks like a flat plate with thousands of carefully placed holes that look sort of random. It's 1" or less thick and fits between the GOM and 1" rigid fiberglass. I assume it works, but does anyone have experience with it? Doesn't the additonal rigid fiberglass on the rear wall deaden the room even more?
Yes, at mid and high frequencies (500 Hz and up). If your theater cannot tolerate much additional absorption, I would not use the Flattfusor.

Quote:
The Flatffusor doesn't seem to diffuse as well as the Hemiffusor, but it's installation is certainly easy. I assume some diffusion is better than none.
Yes. In the case of the Flatffusor, substantial absorption is added. I don't have the specs from RPG on this absorption, other than for an E-400 (400 mm from hard surface) mounting, which is not typical for wall use. But I would count on losing more sound to absorption than diffusion. That's been my experience with this product, anyway.

Quote:
RPG's literature is confusing in that it doesn't indicate to me that the diffusor covers all the audio frequency spectrum. It says it "provides uniform sound diffusion at high and mid band frequencies and crosses over to pure absorption below the difffusive cutoff." What frequency is the cutoff? Is diffusion preferred across the entire audio spectrum?
Yes, it's desirable, but not possible. Practical diffusers are not deep enough to do much at low frequencies -- below about 500 Hz.


Regards,

Terry
 
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