Reasonably Priced Acoustic Diffuser

B

BigDan79

Member
Thread Starter
Joined
Dec 31, 2019
Posts
111
Location
Ohio
More  
Preamp, Processor or Receiver
Emotiva XMC-2
Main Amp
Emotiva XPA-9 Gen3
Additional Amp
Emotiva XPA-6 Gen3
Universal / Blu-ray / CD Player
Panasonic UB820 4k Player, Apple 4k
Streaming Equipment
Apple 4K
Front Speakers
Arendal 1723 Tower
Center Channel Speaker
Arendal 1723 Center
Surround Speakers
Arendal 1723 Surround
Surround Back Speakers
Arendal 1723 Surround
Front Height Speakers
SVS Prime Elevation
Rear Height Speakers
SVS Prime Elevation
Subwoofers
2 Paradigm PW-2200 v.2, 1 Rythmik FV18
Video Display Device
LG C1 77" OLED
Other Equipment
MiniDSP
I am looking for acoustic diffusers but most seem extremely expensive for what they are. I found these panels on Amazon. I was curious if anyone has used them or has a recommendation for something that works good but is affordable.
49787
 
Hey Dan,

Much like thin acoustic "waffle" foam panels being described as "bass traps", these 1" depth stamped thin plastic geometric tiles are being completely misrepresented. In fact this one is a flat out scam. While it may offer an interesting appearance from an architectural and interior design standpoint, it is a complete non starter as a diffuser. Any three dimensional geometric acoustic diffuser that does not exhibit at least a 4-5" variation in the depth of it's shaped surface is a waste of time. It is this variation in depth that provides the diffusion and dictates the frequency bandwidth being diffused. We also want to avoid simple repeating geometric patterns as an identically repeated shape does not randomize the reflections and therefore is not truly providing diffusion. The pictured product fails in all regards. Sorry.

The least expensive effective purely diffusive room treatments will be DIY. I particularly like the Poly-Cylindrical Diffuser for its efficacy, simplicity of its design, and inexpensive and simple DIY construction. Check out this CAM Forum link for my old build thread.
 
Last edited:
Thank you for the reply. Are there any cheaper diffusion options? Seems the ones I have found seem way overpriced for what they are.
 
Dan,

Any worthwhile commercially made product will be much more expensive than the essentially worthless thin plastic tiles from Amazon which you posted the pic of. When it comes to value-conscious commercially made simple geometric diffusors, off the top of my head would be the Auralex T'fuzor and new Hemisphere. From GIK Acoustics also makes a simple geometric diffuser, the Evolution PolyFuzor. If you wanted to go with a more sophistcated QRD phase grating diffuser, GIK Acoustics offers the Gridfuzor QRD and PI AUDIO GROUP offers their AQD diffuser in both 4'x2' and 2' square sizes. Be aware that phase grating QRD or primitive root diffusers like the GIK Gridfuzor and PI AQD are trickier to work as their reflected field sounds really weird when you are up close. Typically QRDs need to be a minimum of 5-to-8 feet distant from the listeners ears to work properly.

I'll wrap it up with the observation that all the aforementioned products would be considered among the cheapest commercial diffusers that actually work. If you want to spend less then you are back to DIY.

Be well,
Vince
 
Something you might look into is potted plants... A few "stands" of bamboo in various sizes live or dried might help depending on where you need that diffusion... And it is something the other half might be good at... Looking at your setup in the showcase items, you may need some bass trapping, some wide band absorption and some wide band diffusion... I even put a wide band absorber over my TV when it was not in use and I was listening to music...
 
I was also looking for lower priced options, since so many of them are priced outside of my budget.

I went with a product similar to the white ones that you looked at, but these are black and have a different pattern to them. Knowing that they wouldn't do much because of their lack of depth, I mounted them on foam core panels and a makeshift wooden framwork so that they would stick out about 9" from the wall at an angle. Kind of like a triangular version of the geometric diffusers people make with sonotubes.

Here's what they look like:

49880


They're about 40" tall and 30" wide, I've got two along the sides of the room, and some 60" tall ones on the back wall.

I think the room sounds better, and may add some more in the future, and even expand them to the ceiling.

It seems like there would be a market for some inexpensive plastic skyline diffusers, but I haven't seen any to this point. It wouldn't be too hard to make them with a vacuum forming machine.

Scott
 
Build your own guys.

What kind of diffussion and where is best place to start. 1d / 2d ceilling, behind etc? what are you wanting to achieve.

Remember you need room for diffusion to work, sticking one right behind you 20cm away wont do anything. i think 1.5/2m is about the minimum distance from Listener to the diffusor that you would want to use.

ive built all my own accoustic pannels and experimenting with diffusion myself. its a tricky beast.
Small rooms focus almost all effort into THICK absorption first (min 100mm imo) - once you have those you can simply put some wood covers over SOME of them with some fancy patterns cut out with a router to get the desired ballance between absorbtion and diffusion.

A simple and effective diffusion is just to bend some Hardboard into a "half cylinder" (like if you cut a tube into 2, or indeed like the shape of this bracket>> )
you would then glue fabric or thin foam and fabric, or fill the behind with rockwool etc.... to tune the sound as desired.

I believe a shallow angle is better where there are not likely to be any flat faces hit by sound o more like a bracket ) than a C shape.

These seem to do the trick well and are aparently "phase coherant" ( i think that means they dont mess with the phase)

I folded some thick black card into the shape ( like that... then stand facing a foot or so away and speak into the wall, you will hear your own voice reflected back at you, where as if i put the ( shaped card there and hold it in place with some temporary tape, when i speak into it, the sound is NOT reflected directly back and is spread out, the result is a quieter reflection in the direct.

This is just my experimentation in my room. but i would encourage you to do simple tests first before spending.
 
Last edited:
UKSPAWN said:
...Remember you need room for diffusion to work, sticking one right behind you 20cm away wont do anything. i think 1.5/2m is about the minimum distance from Listener to the diffusor that you would want to use.
Click to expand...

Oh a phase grating QRD or Primitive Root diffuser will certainly do something when you are sitting in its nearfield. It just won't do something good! :hush:

UKSPAWN said:
...A simple and effective diffusion is just to bend some Hardboard into a "half cylinder" (like if you cut a tube into 2, or indeed like the shape of this bracket>> )

I believe a shallow angle is better where there are not likely to be any flat faces hit by sound o more like a bracket ) than a C shape.

These seem to do the trick well and are aparently "phase coherant" ( i think that means they dont mess with the phase)
Click to expand...

What @UKSPAWN is describing is a Poly-Cylindrical (or Poly for short) Diffuser. I had already mentioned Polys and provided a link to a DIY Poly build thread in an earlier reply. Its worth reiterating though that polys are simple to DIY and the most forgiving sort of diffuser in use. My music and cinema room makes extensive use of DIY poly-cylindrical diffusers on all four walls. However I also employ DIY 5-6" deep broad band absorptive panels along the sidewalls and ceiling, a fractal QRD array on the rear wall, some Binary Amplitude Diffuser/Absorber (RPG BAD Arc) hybrid panels on the front and rear walls, and ASC Tube Traps in all four corners.

IMG_0400.JPG


Screen Shot 2021-11-12 at 12.17.16 PM.png


IMG_0236.JPG


IMG_0048.JPG
 
VinceHoffman said:
Oh a phase grating QRD or Primitive Root diffuser will certainly do something when you are sitting in its nearfield. It just won't do something good! :hush:
Click to expand...

:p that was my intended meaning yes.


Nice room my friend

What is the distance from your ear to the QRDs at the rear? roughly
 
UKSPAWN said:
...What is the distance from your ear to the QRDs at the rear? roughly
Click to expand...

My pic makes the rear wall look closer than it is @UKSPAWN . The wall is actually almost 6 feet behind the listeners ears. The front of the nearest modulation of the fractal QRD array is just over 5 feet from the MLP. The diffuser's low frequency cut-off for efficient diffusion is 975Hz (14 inches) so I'm safely well outside of the 3x longest diffused wavelength minimum distance requirement for phase grating diffusers.

IMG_0452.JPG
 
and more subs hiding behind.

Again, nice room mate :T
 
UKSPAWN said:
and more subs hiding behind.

Again, nice room mate :T
Click to expand...

Yup. Four Seaton Submersive HP subs in a distributed bass array. The Submersives are located with their acoustic centers at .25 and .75 of the front and rear wall width. I use a DSPeaker Anti-Mode 2.0 in its multi-sub mode to time align the front and rear pairs and apply parametric EQ to just the subs. I don't use any other electronic room correction for stereo or multi-channel playback.
 
I really like the looks of those panels with the holes. I can’t go too crazy because the wife would kill me but if I got something that looked good she would be more accepting. I think she would be ok with those. Are there step by step directions for those style?

VinceHoffman said:
Oh a phase grating QRD or Primitive Root diffuser will certainly do something when you are sitting in its nearfield. It just won't do something good! :hush:



What @UKSPAWN is describing is a Poly-Cylindrical (or Poly for short) Diffuser. I had already mentioned Polys and provided a link to a DIY Poly build thread in an earlier reply. Its worth reiterating though that polys are simple to DIY and the most forgiving sort of diffuser in use. My music and cinema room makes extensive use of DIY poly-cylindrical diffusers on all four walls. However I also employ DIY 5-6" deep broad band absorptive panels along the sidewalls and ceiling, a fractal QRD array on the rear wall, some Binary Amplitude Diffuser/Absorber (RPG BAD Arc) hybrid panels on the front and rear walls, and ASC Tube Traps in all four corners.

View attachment 49947

View attachment 49948

View attachment 49949

View attachment 49950
Click to expand...
 
BigDan79 said:
I really like the looks of those panels with the holes. I can’t go too crazy because the wife would kill me but if I got something that looked good she would be more accepting. I think she would be ok with those. Are there step by step directions for those style?
Click to expand...

Hey Dan,

If you are trying to achieve a good acoustic end result, its not about buying or DIY-ing what you think looks cool. It's about choosing the specific acoustic treatment tools that address the sonic warts your particular room exhibits. Room acoustics best practice is to always begin with corner bass traps along with broadband absorptive treatments placed at the primary reflection points on the walls and ceiling. If you choose complimentary colors for the fabric upholstery of the treatments, you shouldn't get much in the way of flack from the Mrs. After all, she was already cool with a room full of black loudspeakers scattered all around the room, gear racking, and a huge TV! Once you have those cornerstones of good acoustics in place, you can do some listening and better still some reverberation time measurements with REW. This will provide some indicator as to where you may want to go from there insofar as adding more absorption or some diffusion (if the room dimensions are large enough to accommodate the latter).

FYI, the binary amplitude diffuser panels you were admiring are an expensive commercial product, the RPG BAD Arc. They aren't normally naked and in their current naked state, they are uglier than my pics suggest. I stripped off the original Guilford of Maine upholstery to modify the panel depth and add additional absorbent stuffing to better suit my needs. They will be reupholstered in a complimentary color of the same GoM fabric as soon as my local upholstery shop has time to do so.

Screen Shot 2021-10-29 at 12.03.36 AM.png


The most cost effective commercial alternative to the spendy RPG BAD Arc is a flat faced hybrid diffuser/absorber panel with binary scatter plate made by GIK Acoustics, their 4A Alpha panels and 6A Alpha panels. DIY versions are possible but you would need serious tools and advanced wood working skills to build something that both worked well and was aesthetically pleasing.
 
Last edited:
Thanks for the info. My room is 21x21 and I have absorption panels around the room and one trap in the back corner where I was getting window rattle. Nothing on the ceiling. I need to add traps for my front corners.

I guess I am not sure if I need diffusers. I just read that you “should” treat your room and it would sound better.


49990



VinceHoffman said:
Hey Dan,

If you are trying to achieve a good acoustic end result, its not about buying or DIY-ing what you think looks cool. It's about choosing the specific acoustic treatment tools that address the sonic warts your particular room exhibits. Room acoustics best practice is to always begin with corner bass traps along with broadband absorptive treatments placed at the primary reflection points on the walls and ceiling. If you choose complimentary colors for the fabric upholstery of the treatments, you shouldn't get much in the way of flack from the Mrs. After all, she was already cool with a room full of black loudspeakers scattered all around the room, gear racking, and a huge TV! Once you have those cornerstones of good acoustics in place, you can do some listening and better still some reverberation time measurements with REW. This will provide some indicator as to where you may want to go from there insofar as adding more absorption or some diffusion (if the room dimensions are large enough to accommodate the latter).

FYI, the binary amplitude diffuser panels you were admiring are an expensive commercial product, the RPG BAD Arc. They aren't normally naked and in their current naked state, they are uglier than my pics suggest. I stripped off the original Guilford of Maine upholstery to modify the panel depth and add additional absorbent stuffing to better suit my needs. They will be reupholstered in a complimentary color of the same GoM fabric as soon as my local upholstery shop has time to do so.

View attachment 49987

The most cost effective commercial alternative to the spendy RPG BAD Arc is a flat faced hybrid diffuser/absorber panel with binary scatter plate made by GIK Acoustics, their 4A Alpha panels and 6A Alpha panels. DIY versions are possible but you would need serious tools and advanced wood working skills to build something that both worked well and was aesthetically pleasing.
Click to expand...
 
BigDan79 said:
Thanks for the info. My room is 21x21 and I have absorption panels around the room and one trap in the back corner where I was getting window rattle. Nothing on the ceiling. I need to add traps for my front corners.

I guess I am not sure if I need diffusers. I just read that you “should” treat your room and it would sound better.
Click to expand...

Well the pic you just provided shows a few broadband panels on the front wall, something I didn't see in the showcase pic linked to your account Dan. How about you provide a complete set of current pics of your room? Additionally I am curious about the dimensions of the traps you are currently using along with just what sort of absorptive material is behind the upholstery?
 
Here is what I bought:

www.acoustimac.com

Executive Acoustic Panel 422 - 48"x24"x2"

2" thick acoustic panels. 48"x24"x2"Our Executive Series was born to be the perfect compliment to any decor. The Executive Series Acoustic Panel is wrapped in a fabric that is comparable to Guilford of Main, with out the heavy price tag.
www.acoustimac.com www.acoustimac.com

www.acoustimac.com

Acoustimac DMD-BT6000C Corner Bass Traps 48"X24"X6"

DMD BT-6000C Corner Bass Trap 48" X 24" x 6" Used to control and clean up low frequencies, our DMD Bass Traps will help to keep bass from being too "boomy" or "muddy".
www.acoustimac.com www.acoustimac.com

I have some on the rear also. I can take better pictures tomorrow


49997
 
How does it sound to you @BigDan79 ??? Have you used REW to get a feeling as to what's going on in the room ??? Your room looks nice and clean so far... Additional bass traps and wide band absorbers, as you point out above, will help dial the room in... I would not worry about diffusion yet...
 
VinceHoffman said:
Hey Dan,

If you are trying to achieve a good acoustic end result, its not about buying or DIY-ing what you think looks cool. It's about choosing the specific acoustic treatment tools that address the sonic warts your particular room exhibits. Room acoustics best practice is to always begin with corner bass traps along with broadband absorptive treatments placed at the primary reflection points on the walls and ceiling. If you choose complimentary colors for the fabric upholstery of the treatments, you shouldn't get much in the way of flack from the Mrs. After all, she was already cool with a room full of black loudspeakers scattered all around the room, gear racking, and a huge TV! Once you have those cornerstones of good acoustics in place, you can do some listening and better still some reverberation time measurements with REW. This will provide some indicator as to where you may want to go from there insofar as adding more absorption or some diffusion (if the room dimensions are large enough to accommodate the latter).

FYI, the binary amplitude diffuser panels you were admiring are an expensive commercial product, the RPG BAD Arc. They aren't normally naked and in their current naked state, they are uglier than my pics suggest. I stripped off the original Guilford of Maine upholstery to modify the panel depth and add additional absorbent stuffing to better suit my needs. They will be reupholstered in a complimentary color of the same GoM fabric as soon as my local upholstery shop has time to do so.

View attachment 49987

The most cost effective commercial alternative to the spendy RPG BAD Arc is a flat faced hybrid diffuser/absorber panel with binary scatter plate made by GIK Acoustics, their 4A Alpha panels and 6A Alpha panels. DIY versions are possible but you would need serious tools and advanced wood working skills to build something that both worked well and was aesthetically pleasing.
Click to expand...
VinceHoffman said:
Oh a phase grating QRD or Primitive Root diffuser will certainly do something when you are sitting in its nearfield. It just won't do something good! :hush:



What @UKSPAWN is describing is a Poly-Cylindrical (or Poly for short) Diffuser. I had already mentioned Polys and provided a link to a DIY Poly build thread in an earlier reply. Its worth reiterating though that polys are simple to DIY and the most forgiving sort of diffuser in use. My music and cinema room makes extensive use of DIY poly-cylindrical diffusers on all four walls. However I also employ DIY 5-6" deep broad band absorptive panels along the sidewalls and ceiling, a fractal QRD array on the rear wall, some Binary Amplitude Diffuser/Absorber (RPG BAD Arc) hybrid panels on the front and rear walls, and ASC Tube Traps in all four corners.

View attachment 49947

View attachment 49948

View attachment 49949

View attachment 49950
Click to expand...

@VinceHoffman, what time are we coming over??? Great room!
 
I think it sounds pretty good. The panels helped with reflection issues I was having. I have used REW for the sub calibration. How can you tell from REW measurements whether additional sound treatments are needed?


ddude003 said:
How does it sound to you @BigDan79 ??? Have you used REW to get a feeling as to what's going on in the room ??? Your room looks nice and clean so far... Additional bass traps and wide band absorbers, as you point out above, will help dial the room in... I would not worry about diffusion yet...
Click to expand...
 
BigDan79 said:
I think it sounds pretty good. The panels helped with reflection issues I was having. I have used REW for the sub calibration. How can you tell from REW measurements whether additional sound treatments are needed?
Click to expand...

Use "RT60 Decay" too see if you need more absorption to get to the reverb level you want above ~200hz (200-300ms i like)

if they are fine but bass is still bad just make the absorbers you have THICKER

If your room is too dead (<200ms) you can add flat wood fronts with holes cut in to 1 or 2 of your absorbers. (add more holes as you go to reduce reflectivity and tune)
 
VinceHoffman said:
ROAD TRIP!!! :T:T:T Well @Todd Anderson if you ever decide to make that long drive to my neck of the woods here in Southern Ontario, I'm happy to host an afternoon or an evening listening and viewing session.
Click to expand...

waze says I’ll be there in 8hr. 59min! ;-)
 
UKSPAWN said:
Use "RT60 Decay" too see if you need more absorption to get to the reverb level you want above ~200hz (200-300ms i like)

if they are fine but bass is still bad just make the absorbers you have THICKER

If your room is too dead (<200ms) you can add flat wood fronts with holes cut in to 1 or 2 of your absorbers. (add more holes as you go to reduce reflectivity and tune)
Click to expand...

OK. I have to recalibrate the my subs again anyway after moving everything after the upgrade. I will add this to that process.
 
Would appreciate any comments about my RT60 Decay. No diffusor panels installed yet.

Present Treatment
I have installed DIY treatments that include rear corner bass traps, absorption panels on front, side, rear walls and a several on the ceiling.

3D Rendering of my room, dimensions 22' x 10' x 7.5' (L W H),

...\
Tims HTR Dec 18 2021 Atmos Relocate.png


Here is my measured REW RT60 for the the front, right, center speaks at the MLP.

Den6a RT60 Graph.jpg


Thanks Tim
 
You must log in or register to reply here.

Popular tags

20th century fox 4k blu-ray 4k uhd 4k ultrahd action adventure animated animation bass blu-ray calibration comedy comics denon dirac dirac live disney dolby atmos drama fantasy hdmi 2.1 home theater horror kaleidescape klipsch lionsgate marantz movies onkyo paramount pioneer rew romance sci-fi scream factory shout factory sony stormaudio subwoofer svs terror thriller uhd ultrahd ultrahd 4k universal value electronics warner warner brothers well go usa
Back
Top