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Spacing Diffusor Panels

How important is it to have all your diffuser panels adjacent to each other?  If you’re placing diffusion behind your speakers and the wall is 20ft wide how important is it to have No Gaps between panels? If the panels are 3ft wide and you’re using three should they be arranged adjacent to each other thereby creating a continuous nine foot wide diffusion area or can they be separated by two feet or more? Does a non continuous alignment adversely impact the diffusion?
stickman451
auxinput
2,920 posts
 

First question.  Are these QRD (Quadratic Residue Diffuser) diffusors?  If so, then the placement and direction will definitely affect acoustics in different ways.  When I say "direction" I mean the placement of where the shallow slots are vs. the deep slots - also vertical or horizontal.  It the room is huge, such as 20 feet by 20 feet, then it may not matter much (unless the diffusors are placed in the corners).

There is no hard and fast rule on placement.  I would probably say that you should not place the close to or behind the speakers because they can actually cause phasing problems with certain frequencies the speakers are producing.  They can be placed together or you can split them apart by a couple of feet.  Do you have the ability to temporarily mount them and listen to the result?  This may be an exercise in experimentation before you decide on the best result.  It was certainly this way for me when I added QRD diffusors to my room.

stickman451 OP
553 posts
 
I agree, you don’t want diffusion too close to your seating position  or speakers because comb filtering can become an issue.  From what little I understand that effect is partially dependent upon the effective frequency range of the diffusion panels which is determined by their well depth.  The diffuser I’m using is a simple one-dimensional DIY design (they’re called HomeDepot Diffusors 
https://www.google.com/search?rlz=1C9BKJA_enUS796US796&hl=en-US&ei=5atMW-

They are hanging on the front wall approximately 6.5 - 7 feet from my Magnepan’s.  Actually they are sitting directly on the floor at this point, I haven’t gotten around to mounting them on the wall yet.  

auxinput
2,920 posts
 
yeah, these look like a variation on the QRD type diffusors.  You can cut some 2x4s and just put them under the diffusors to raise them up - or use something else to place them on so that you can hear them up high. 
hornguys
180 posts
 
Since the sound from the back of the panels will not be particularly good, why would you want to diffuse it, thereby adding an unnatural sound to the room acoustics? 

Personally, I would prefer to absorb that back wave.  Reflecting it any manner cannot help, IMO.
stickman451 OP
553 posts
 
It’s my understanding that the sound coming out of the Maggie panels, front and back is exactly the same; only they are in opposite phase.

i’ve tried Absorption and did not like the result; just deadens everything especially the top end.

The diffusors do expand the sound field behind the panels and I like that effect.  Balance is the key; not too much diffusion and not too little.

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