Can you have too much diffusion

HiFi

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Oct 11, 2020
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Question..... within reason can one have too much diffusion On the front wall in a two channel audio room?

Bass traps are DYI and offer no diffusion. A mistake I made when I built them.

My front wall is only 11 ft wide.
C1B9EF74-6072-4F64-B378-DFDD5CD6FB5C.jpeg
Thanks in advance
 

spiritofmusic

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Hi, I'm running GIK absorbers and bass traps on front wall, the sound suffers a little without them. Considering moving to something like Acustica Applicata Daads or Stillpoints Apertures which offer a combination of diffusion and absorption.
 

advanced101

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On the front wall I prefer absorption panels with some kind of limiting reflecting front plate. The Alpha panels from GIK are very good for the price. I much prefer Apertures though. Apertures, although silly money, sound the best to me on the front wall and all reflection points. I have tried a bunch including pure absorption, pure diffusion and various mixes.

There is no right or wrong, experimentation is the only way. Buy a few panels of a different type and give them a try.
 

MTB Vince

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IMG_7317.JPG

A mix of diffusion, bass trapping, and broadband absorption. I'm considering adding some more diffusion though- in the form of scatter plates on the fronts of the two broadband absorption panels.
 
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spiritofmusic

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Advanced, how do you set up your Apertures?
Tima has been running his room with vertical columns of two panels on the front wall: central and maybe 3' to the R and L, so six Apertures in total on front wall; and at side wall first reflection points.
 
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advanced101

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I like 2 at each reflection point. I have experimented at the front wall and would agree 6 there. I need to buy more but may build my own.
 

spiritofmusic

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So, two vertically on midline front wall. How close to those would the columns R and L be? Simple matter of experimentation?
 

advanced101

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For me, I use the panels to cover windows but they are symmetrical. LR about 24” away from center. So no experimentation. I would say because of those windows, treatments at the front of the room are more important for me than they might be for someone with a solid wall.
 

sbnx

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Too much diffusion causes confusion. But it doesnt look like you have too much
 
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spiritofmusic

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After a little prodding from a member here, I'm gonna investigate Artnovion panels. Like Stillpoints Apertures, they are hybrid absorber/diffusers, but 40% more affordable. Look very smart too.

Eiger corner bass traps and Avalon Flow hybrid panels for front and side walls.
 

advanced101

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After a little prodding from a member here, I'm gonna investigate Artnovion panels. Like Stillpoints Apertures, they are hybrid absorber/diffusers, but 40% more affordable. Look very smart too.

Eiger corner bass traps and Avalon Flow hybrid panels for front and side walls.
There is a bit more going on inside of an Aperture. The patent is available online and will give you insight on the construction. Although this won’t tell you how they sound. For bass trapping, I would look elsewhere though. For reflection points, Apertures are my favorite.
 

spiritofmusic

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I'll hopefully be able to trial both.
 

hemiutut

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Sep 30, 2021
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Question..... within reason can one have too much diffusion On the front wall in a two channel audio room?

Bass traps are DYI and offer no diffusion. A mistake I made when I built them.

My front wall is only 11 ft wide.
View attachment 70414
Thanks in advance
Hello
Do you have measurements with Room Eq Wizard for example?
What measures does the room have?
How far away is the listening point from the front and rear wall?

Written with translator.

Greetings
 

microstrip

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May 30, 2010
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Question..... within reason can one have too much diffusion On the front wall in a two channel audio room?
Proper diffusion needs a lot of space and distance from the speakers - in most rooms diffusors just work as partial absorbers and partial reflectors.

No diffusor is 100% diffusor - many devices being sold as diffusors absorb much more than they diffuse, but look very nice in the room.
 

spiritofmusic

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Micro, that's precisely how my system works, 2.5m behind spkrs, 10 no. 1200x300x12.5mm recycled polyester panels, installed in louvre pattern 45° to wall, just overlapping. Some absorption, and gentle diffusion.
 

microstrip

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Micro, that's precisely how my system works, 2.5m behind spkrs, 10 no. 1200x300x12.5mm recycled polyester panels, installed in louvre pattern 45° to wall, just overlapping. Some absorption, and gentle diffusion.

Adequate distance - the same I have - but what kind of panels do you use to get "gentle diffusion"?
 

spiritofmusic

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Whatever is in these recycled polyester slabs, because the proof is in the eating...tangibly more natural imaging/lack of hash in mids, greater low level resolution/microdynamics.
I had tried more disruptive diffusion, but found effects were too dramatic, almost too dry and tizzy.
 

MTB Vince

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May 11, 2019
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Whatever is in these recycled polyester slabs, because the proof is in the eating...tangibly more natural imaging/lack of hash in mids, greater low level resolution/microdynamics.
I had tried more disruptive diffusion, but found effects were too dramatic, almost too dry and tizzy.
Your polyester wool panels provide no meaningful diffusion @spiritofmusic. They are strictly absorptive. Effective acoustic diffusion is derived from specifically shaped reflective surfaces typically, or in the case of BAD (Binary Amplitude) Diffusors, a reflective face plate with a mathematically derived pattern of holes or slots cut into it's surface to expose an absorptive material (with several inches of depth) behind the holes in the otherwise reflective face plate. Technically the latter is actually a hybrid of diffusor and broadband absorber.

The unpleasant sonic artifacts you describe having experienced with "more disruptive diffusion" sounds a lot like you either did not have a sufficient balance of absorption to reflection, and thus an overly reverberent room... Or you were not observing the minimum sound source/MLP distance requirements which all phase grating diffusers exhibit. If the loudspeaker or listening position is within the diffusor's nearfield (less than 4 wavelengths of the diffuser's low frequency cut off), the not yet fully integrated reflections from the diffuser will manifest as an odd wiry, tizzy quality due to comb filtering.
 
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spiritofmusic

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I'm happy to accept that. However these panels have produced a totally different outcome from my previous GIK absorbers, and the current sound is more akin to the sound I heard w alternative (albeit too excessive or inappropriate or poorly balanced) diffusion, just a lot more palatable. That suggests *some* diffusion is going on, in balance w the mild absorption the panels provide.
 

pjwd

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Jun 23, 2015
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Your polyester wool panels provide no meaningful diffusion @spiritofmusic. They are strictly absorptive. Effective acoustic diffusion is derived from specifically shaped reflective surfaces typically, or in the case of BAD (Binary Amplitude) Diffusors, a reflective face plate with a mathematically derived pattern of holes or slots cut into it's surface to expose an absorptive material (with several inches of depth) behind the holes in the otherwise reflective face plate. Technically the latter is actually a hybrid of diffusor and broadband absorber.

The unpleasant sonic artifacts you describe having experienced with "more disruptive diffusion" sounds a lot like you either did not have a sufficient balance of absorption to reflection, and thus an overly reverberent room... Or you were not observing the minimum sound source/MLP distance requirements which all phase grating diffusers exhibit. If the loudspeaker or listening position is within the diffusor's nearfield (less than 4 wavelengths of the diffuser's low frequency cut off), the not yet fully integrated reflections from the diffuser will manifest as an odd wiry, tizzy quality due to comb filtering.
Vince
Marcs panels are not a conventional method of treatment . They would be better described as reflector/absorbers as they are located to prevent first reflections from front wall, side walls and ceiling. They are also angled to ensure that none of the sound reflected from them is directed at the listner . This avoids the issue of reflected non correlated sound from either variable absorbtion of broad based absorbtion or timing and gating distortion from diffusers smearing the direct sound within the magic 8-10 ms.
Of course theses only work as absorbers over a limited band so lower frequncies will pass through on their normal reflected path but will be slightly attenuated . The absorbtive nature also helps a bit with edge diffraction.
You could have much fancier design of these panels with multiple materials etc but these are very cost effective and work !
Interestingly you now see a plethora of these systems in baffle ceilings in open plans offices, public spaces etc. because of the cost compared to fancier systems, its a recycled product and you can have sculptural shapes.
Cheers
Phil
 

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