Quantcast
DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals) - Page 9 - Gearspace.com
The No.1 Website for Pro Audio
DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals)
Old 14th March 2013 | Show parent
  #241
Lives for gear
 
Jens Eklund's Avatar
 
🎧 10 years
Quote:
Originally Posted by scoring4films ➡️
Aren't deeper wells better? Does anyone know how the performance of the A1LF compares to the more common diffusor designs (e.g. Realtraps Diffusor)?
https://gearspace.com/board/8160618-post43.html

https://gearspace.com/board/8443037-post115.html

https://gearspace.com/board/7467375-post2.html

Old 14th March 2013
  #242
Lives for gear
 
scoring4films's Avatar
 
🎧 10 years
Thanks for the links Jens. I understand some, but not all of the data/graphs. I wish I did.

I have 3 areas that I'd like to treat with diffusion - the side walls next to my monitors and the ceiling above my monitors/mix position. In all three cases, the area available for treatment is ~1.2 meters square. Mix position is ~2m from the sidewalls.

I'm trying to figure out if Tim's A1LF, modified into an array of 6 modules (2 rows of 3) would be the best use my time/energy/funds for building these DIY diffusors, or if I should stick with the more commonly used designs, some of which use deeper "wells".

I've built quite a bit of resistance-to-flow style trapping already, some of which had to be dismantled and rebuilt because I jumped in too quickly, without enough information/forethought. I guess I'm trying to avoid another case of "DIY-ers remorse", if I can.

Any suggestions greatly appreciated!
Old 14th March 2013 | Show parent
  #243
Lives for gear
 
Jens Eklund's Avatar
 
🎧 10 years
Before adding diffusers, you should first think about what kind of response you’re after. There are very few design concepts that favor early reflections (even if diffused, in a limited frequency range especially) and the ones that do are not that common. If you still opt for diffusers relatively close to the sweet spot that will partly scatter energy back to the sweet spot relatively soon compared to direct sound (sooner than traditionally recommended ISD-gap), I would in this particular case recommend 2D diffusers since these feature a higher attenuation of incoming specular energy compared to 1D diffusers (this is otherwise normally the biggest drawback of 2D diffusers), and if being specific, a 2D diffuser that not only operates in the full frequency range (down to at least 500 Hz), but also offers higher than average redirection (scattering) at the angle of incidence of the first order reflection that arrives too soon to the listening position. You might be able to achieve something that could be called “semi ambechoic”.

More on diffuser placement here:
https://gearspace.com/board/8295482-post3.html
Old 14th March 2013
  #244
Lives for gear
 
scoring4films's Avatar
 
🎧 10 years
Thanks Jens. That's exactly the sort of advice I was looking for. I think you may have saved me from more DIY-ers remorse

I wasn't after any particular response, I just wanted to treat my room's first reflection points with something other than absorption, because my room is already packed with several large broadband traps, and not surprisingly it sounds a bit dead.

But after reading your post and doing a little more research, I understand that diffusors might not be the best way to treat first reflections (at least not with the usual 6" deep or less type diffusors). I just assumed diffusion would work, based on photos I've seen of studios like George Massenburg's Studio C, where I'm guessing the diffusion does work at first reflection points because the diffusors are so large/deep.

I might still build an A1LF array, but install it in the middle of my back wall, where it's low profile feature will be useful.

I already have a cloud-style absorber in place and I already have small RFZ absorber side panels half built. I guess I'll finish them off and give them a try.

thanks again!
Old 14th March 2013 | Show parent
  #245
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by scoring4films ➡️
Thanks Jens. That's exactly the sort of advice I was looking for. I think you may have saved me from more DIY-ers remorse

I wasn't after any particular response, I just wanted to treat my room's first reflection points with something other than absorption, because my room is already packed with several large broadband traps, and not surprisingly it sounds a bit dead.

But after reading your post and doing a little more research, I understand that diffusors might not be the best way to treat first reflections (at least not with the usual 6" deep or less type diffusors). I just assumed diffusion would work, based on photos I've seen of studios like George Massenburg's Studio C, where I'm guessing the diffusion does work at first reflection points because the diffusors are so large/deep.

I might still build an A1LF array, but install it in the middle of my back wall, where it's low profile feature will be useful.

I already have a cloud-style absorber in place and I already have small RFZ absorber side panels half built. I guess I'll finish them off and give them a try.

thanks again!
Right on. Blackbird Studio C is designed around the idea of using liberal 2D diffusion to achieve a level of clarity that may be acceptable for critical listening (depending on one’s school of thought). But most control rooms focus on absorption-heavy treatment strategies. In most cases diffusion is only complementary to a treatment strategy that starts with absorption.

If you build an A1-LF array, you should mount the modules using a profiled modulation for a big performance boost:

Leanfuser with profiled modulations

The above link shows 5-module and 7-module profiled modulations and the resulting diffusion coefficients.
Old 15th March 2013 | Show parent
  #246
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by John White ➡️
Tim,

Finally got an opportunity to put your plans into effect. I was very inspired by "optimization" in regards to the repetition, conservation of building and by the performance of a very trim diffuser. I liked the way your plans were designed such that the profile was a series of pieces that make a whole.

I'd like to try to incorporate these same ideals into my building practices going forward. I'm not entirely sure how that may materialize, but I will certainly keep it in mind. Ironically it turned out to be a bit more complicated than that for these units.
These look awesome John!

I'm glad that you appreciate the modular construction concepts, and it's great to see that you've built these using the profiled modulation on the last page of the blueprints. It complicates the design a little bit, but the overall performance is much better.

Also, I love how you've finished them.

Great work!
Old 15th March 2013 | Show parent
  #247
Lives for gear
 
Bjorn Omholt's Avatar
 
🎧 10 years
No diffuser is spectral neutral. So if you have a goal of accuracy, I would not use diffusion in the early reflection zone. Redirection or absorption are then better options. Instead, use diffusion after a certain time (ISD-gap) behind the seating position.

Ambechoic (Blackbird) is something entirely else and basically practical impossible to imitate for most people.
Old 15th March 2013 | Show parent
  #248
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by bwo ➡️
No diffuser is spectral neutral. So if you have a goal of accuracy, I would not use diffusion in the early reflection zone. Redirection or absorption are then better options. Instead, use diffusion after a certain time (ISD-gap) behind the seating position.

Ambechoic (Blackbird) is something entirely else and basically practical impossible to imitate for most people.
+1

Or, for very high accuracy (i.e., a Non-Environment control room), the back wall, ceiling and sidewalls are entirely absorptive, the floor is reflective, and the front wall is reflective / diffusive (with flush-mounted loudspeakers).
Old 15th March 2013
  #249
Lives for gear
 
John White's Avatar
 
🎧 10 years
Thanks Tim.

Yes, the modulation kind of throws the repetition out the window somewhat, but some of the patterns still emerge. I do need to remind myself that it would have been a bit easier had it not been for the design with the alternating stain/paint and the resulting two different materials. That was with 3/4"/19mm steps totaling 8.25"/167mm in depth at it's apex.

Independent units of 7 wells are of course easier to pattern and make off the assembly line. Here are two units each sandwiching a poly to create a large and effective dispersion array. Stain on the "1" and "2" steps, but not the 3 this time. The far unit looks deeper only because it's mounted over a panel trap. Still the same size. Also using 3/4" steps.



I'm looking forward to more builds and will try the 7 unit modulation (same step pattern) at some point if I have the wall length. The other one was just a bit tight for the wall space.
Old 16th March 2013
  #250
Lives for gear
 
AwwDeOhh's Avatar
 
🎧 10 years
Love the 2-tone build, John!

Thanks for sharing.
Old 16th March 2013 | Show parent
  #251
Lives for gear
 
audiothings's Avatar
 
🎧 15 years


Do I see a poly cum metal panel absorber in the corners? Is that steel?
Old 16th March 2013 | Show parent
  #252
Lives for gear
 
🎧 5 years
Quite nice! Any more pics?
Old 16th March 2013 | Show parent
  #253
Lives for gear
 
Bjorn Omholt's Avatar
 
🎧 10 years
Quote:
Originally Posted by Arqen ➡️
+1

Or, for very high accuracy (i.e., a Non-Environment control room), the back wall, ceiling and sidewalls are entirely absorptive, the floor is reflective, and the front wall is reflective / diffusive (with flush-mounted loudspeakers).
A bit off topic, but I don't really fancy Non-Environment rooms. It's basically a semi anechoic room, so very dead sounding. It can also be discussed if such a room, with absorption in the back, leads to localization errors.

It's possible to have accuracy with both liveleness and spaciousness. Much better IMO. That's what LEDE/RFZ gives you.
Old 18th March 2013 | Show parent
  #254
Lives for gear
 
John White's Avatar
 
🎧 10 years
Quote:
Originally Posted by audiothings ➡️
Do I see a poly cum metal panel absorber in the corners? Is that steel?
A bit OT:

Yes, metal poly's just like the above photo. The more lively side of the room. This is the original photo zoomed out a bit to see them better. 22g. steel, free floating, insulated. I'd link to your thread, though I really don't have anything to add of note.

Old 19th March 2013 | Show parent
  #255
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by John White ➡️
Thanks Tim.

Yes, the modulation kind of throws the repetition out the window somewhat, but some of the patterns still emerge. I do need to remind myself that it would have been a bit easier had it not been for the design with the alternating stain/paint and the resulting two different materials. That was with 3/4"/19mm steps totaling 8.25"/167mm in depth at it's apex.

Independent units of 7 wells are of course easier to pattern and make off the assembly line. Here are two units each sandwiching a poly to create a large and effective dispersion array. Stain on the "1" and "2" steps, but not the 3 this time. The far unit looks deeper only because it's mounted over a panel trap. Still the same size. Also using 3/4" steps.

I'm looking forward to more builds and will try the 7 unit modulation (same step pattern) at some point if I have the wall length. The other one was just a bit tight for the wall space.
I've got to hand it to you, I really love the clean, two-tone look. Your whole room looks great, and the way you've worked these diffusers into the design is very sharp.

I look forward to seeing more builds of yours!
Old 19th March 2013 | Show parent
  #256
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by bwo ➡️
A bit off topic, but I don't really fancy Non-Environment rooms. It's basically a semi anechoic room, so very dead sounding. It can also be discussed if such a room, with absorption in the back, leads to localization errors.

It's possible to have accuracy with both liveleness and spaciousness. Much better IMO. That's what LEDE/RFZ gives you.
I think it depends on your goals. I love the versatility of LEDE/RFZ rooms, but some designers consider them not well suited to critical listening (especially when it comes to surround sound).

In a NE control room you get better listening clarity, and you still get that reflection off the floor and front wall when you speak in the room, so it does not sound completely dead.

It is a matter of taste, but I've not heard many complaints from recording engineers who have tried working in NE rooms. Philip Newell makes some compelling arguments for Non Environment rooms in chapters 13 and 16 of his book Recording Studio Design. In theory, people tend to not like them. In practice, people tend to love them (but I have no statistical evidence to back that up). And of course, all people have different tastes so it's hard to say what type of room is better where subjective listening is concerned.
Old 26th June 2013
  #257
Here for the gear
 
🎧 5 years
A1-LF questions

Hi there. I am new to all of this and had a few questions about the stepped diffuser A1-LF. What effects does this diffuser have on sound at a close range say within 3-20 feet away from the sound source? The other design seems to spread sound out nicely because of the "roundness". The stepped design will make a different sound effect right?
Old 26th June 2013 | Show parent
  #258
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by Novellorecording ➡️
Hi there. I am new to all of this and had a few questions about the stepped diffuser A1-LF. What effects does this diffuser have on sound at a close range say within 3-20 feet away from the sound source? The other design seems to spread sound out nicely because of the "roundness". The stepped design will make a different sound effect right?

The minimum listening distance for these diffusers is about 5-6', so I would only use them if you plan to be 6' away from the diffusers.

The effect of stepped diffusers is not as intuitive as rounded diffusers, but but these ones scatter sound effectively outside of 6'. Stepped diffusers scatter sound in both space and in time directly, while a semi-cylindrical diffuser scatters sound optimally, but only in space.

In other words, a simple, round cylindrical shape disperses sound only in space directly . . . and any temporal (timing / phase related) dispersion that the user perceives, is an after-effect, or indirect result of that spatial diffusion (e.g., the spatially scattered sound has to bounce around the room and then arrive at the listeners ears in order to be scattered with respect to time for the listener). In contrast, part of the effect of a stepped diffuser is that it causes the reflected sound wave to be dispersed in time directly, and in space directly.

These diffusers were optimized at listening distance of 5 m (16.4 ft), and the performance coefficients shown in the graphs were measured at 10 m (about 33 ft). They will perform best outside of 15', but they should be effective as long as the listening distance is greater than 6'.

For best results you should arrange the diffuser modules using one of the Profiled Modulations given in the last few pages of the blueprints.

Hope this helps! Let me know if it's too confusing and I can give another shot at explaining it .
Old 30th June 2013
  #259
Gear Maniac
 
bassguy6's Avatar
 
🎧 10 years
Here is one of four I made with left over engineered hardwood flooring and underlayment. (I work in a flooring store).
Attached Thumbnails
DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals)-imageuploadedbygearslutz1372629750.570212.jpg  
Old 1st July 2013 | Show parent
  #260
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by bassguy6 ➡️
Here is one of four I made with left over engineered hardwood flooring and underlayment. (I work in a flooring store).
Very cool!

One of my hopes when I made these plans available was to see what kind of creative solutions people could come up with using scrap material.

Great to see those left overs being made into something useful.
Old 3rd July 2013 | Show parent
  #261
Gear Maniac
 
robertopisa's Avatar
 
🎧 10 years
Array with aperiodic modulation {1 0 1 1 0}

Dear Tim,

thanks for the nice post. I am wondering if you have experimented or there is any improvement in using

{1 0 0 1 1}

as aperiodic modulation. Indeed {1 0 0 1 1} is an example of De Bruijn sequence (De Bruijn sequence - Wikipedia, the free encyclopedia) where every two consecutive digits never repeat: 10, 00, 01, 11.

Instead the sequence {1 0 1 1 0} you suggest has repetitions: 10, 01, 11, 10.

Same question for the N=7 elements in the base shape (420mm): is any helpful to have them arranged in an aperiodic modulation of N digits, say {1 0 0 1 1 0 1}? Here every two consecutive digits never repeat in the first five positions (as before, 10, 00, 01, 11) and in the last four positions (11, 10, 01), and every three consecutive digits never repeat: 100, 001, 011, 101.

I think these two sequences seem to mix better the reflections than {1 0 1 1 0} for the base module and than nothing done inside the base. It would be nice to check this by simulation as you already did for the other sequence.


Thanks
-Roberto

Last edited by robertopisa; 3rd July 2013 at 08:19 PM.. Reason: Fixed typos
Old 3rd July 2013 | Show parent
  #262
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by robertopisa ➡️
Dear Tim,

thanks for the nice post. I am wondering if you have experimented or there is any improvement in using

{1 0 0 1 1}

as aperiodic modulation. Indeed {1 0 0 1 1} is an example of De Bruijn sequence (De Bruijn sequence - Wikipedia, the free encyclopedia) where every two consecutive digits never repeat: 10, 00, 01, 11.

Instead the sequence {1 0 1 1 0} you suggest has repetitions: 10, 01, 11, 10.

Same question for the N=7 elements in the base shape (420mm): is any helpful to have them arranged in an aperiodic modulation of N digits, say {1 0 0 1 1 0 1}? Here every two consecutive digits never repeat in the first five positions (as before, 10, 00, 01, 11) and in the last four positions (11, 10, 01), and every three consecutive digits never repeat: 100, 001, 011, 101.

I think these two sequences seem to mix better the reflections than {1 0 1 1 0} for the base module and than nothing done inside the base. It would be nice to check this by simulation as you already did for the other sequence.


Thanks
-Roberto
Hi Roberto,

Thanks for those insights!

I've not tried either of those sequences. I chose {1 0 1 1 0} as the default sequence to optimize diffusers in, mainly because it always results in the first and last shape being mirror images of each other. I followed my intuition (which could be wrong), which told me that an array of shapes that is symmetrical at the left and right edges could be more likely to produce uniform scattering (assuming you insert a random shape into the array).

By optimizing diffusers inside this array (with mirror symmetry in the first and last modules), I expected that the optimization would converge to a better solution (and faster) than if I used another sequence.

I would love to test out those other sequences, but unfortunately my copy of AFMG Reflex software has expired. We've been using Reflex (rather than my own code) to test the resulting performance, because Reflex has been validated against real world results. The diffusion simulation program that I coded has not been validated against real world results, but that might change eventually. I've recently made some improvements to it while working with a client (an acoustics professor who's using my program for some sound scattering research).

If you want to test your ideas out using Reflex, that would be fantastic! Reflex is easy to use. You can download a trial of here and give it a go, if you're up to it. Just an idea.

Thanks for the great question and insights!

Tim
Old 4th July 2013
  #263
Gear Head
 
🎧 5 years
I want to put diffusors between my 2 speakers (front wall). I have already 2 broadband absorder behind each speaker but I have 3-3.5 foots available to put a diffuser.

I was thiking 3D (skyline) but fractals seem fun too.

I have read to diffuse bass we need depth ... so how work the fractal ? It's not depth at all ... it's diffuse some bass too ?

Each side of speaker better to use skyline or fractals ?

(14.5 x 22.5 x 8 foots my room). Speakers at 4-5 foots from the front wall and 3 foots to the side wall.
Old 4th July 2013 | Show parent
  #264
Lives for gear
 
AwwDeOhh's Avatar
 
🎧 10 years
Roberto,

Although this article has to do with QRD diffusors, i believe the principal is the same:
QRDude User guide - Lobes for multiple panels
Explains lobing, and how doing one inverse panel in a series can combat that effect.
Old 4th July 2013 | Show parent
  #265
Gear Maniac
 
robertopisa's Avatar
 
🎧 10 years
I am traveling with an iPad for some days, when back home I will experiment as you suggest. I have some other ideas that I will share as soon as Reflex says OK

Thanks
Roberto


Quote:
Originally Posted by Arqen ➡️
Hi Roberto,

Thanks for those insights!

I've not tried either of those sequences. I chose {1 0 1 1 0} as the default sequence to optimize diffusers in, mainly because it always results in the first and last shape being mirror images of each other. I followed my intuition (which could be wrong), which told me that an array of shapes that is symmetrical at the left and right edges could be more likely to produce uniform scattering (assuming you insert a random shape into the array).

By optimizing diffusers inside this array (with mirror symmetry in the first and last modules), I expected that the optimization would converge to a better solution (and faster) than if I used another sequence.

I would love to test out those other sequences, but unfortunately my copy of AFMG Reflex software has expired. We've been using Reflex (rather than my own code) to test the resulting performance, because Reflex has been validated against real world results. The diffusion simulation program that I coded has not been validated against real world results, but that might change eventually. I've recently made some improvements to it while working with a client (an acoustics professor who's using my program for some sound scattering research).

If you want to test your ideas out using Reflex, that would be fantastic! Reflex is easy to use. You can download a trial of here and give it a go, if you're up to it. Just an idea.

Thanks for the great question and insights!

Tim
Old 4th July 2013 | Show parent
  #266
Gear Maniac
 
robertopisa's Avatar
 
🎧 10 years
Studying the article you suggest as I am curious why certain sequences are preferred to others, thanks
-R

Quote:
Originally Posted by AwwDeOhh ➡️
Roberto,

Although this article has to do with QRD diffusors, i believe the principal is the same:
QRDude User guide - Lobes for multiple panels
Explains lobing, and how doing one inverse panel in a series can combat that effect.
Old 4th July 2013 | Show parent
  #267
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by pompon ➡️
I want to put diffusors between my 2 speakers (front wall). I have already 2 broadband absorder behind each speaker but I have 3-3.5 foots available to put a diffuser.

I was thiking 3D (skyline) but fractals seem fun too.

I have read to diffuse bass we need depth ... so how work the fractal ? It's not depth at all ... it's diffuse some bass too ?

Each side of speaker better to use skyline or fractals ?

(14.5 x 22.5 x 8 foots my room). Speakers at 4-5 foots from the front wall and 3 foots to the side wall.
In a room that size you're much better off controlling bass by absorbing it, rather than trying to diffuse it (this is because low frequencies have very long wavelengths, and they need lots of space to diffuse properly). If you want to improve the low frequency diffusion of these fractal diffusers, you can mount the modules at different depths (for an example, see the "Profiled Modulations" at the end of the blueprints for A1-LF stepped diffuser).

You can download the blueprints here.

Both my diffuser designs and the the Skyline are designed for tight spaces, but they are quite different. If I recall, the Skyline is a special 2D primitive root diffuser (PRD) based on the Cox and D’Antonio-modified PRD (CDMPRD). If this is true, then the skyline is designed to create a notch in the polar response to scatter sound in 3D space, away from the listener. My designs, on the other hand, are 1-dimensional diffusers designed to scatter sound in all directions within a 2D plane (my designs do not have a notch in the scatter polar response, therefore they do send some sound directly back toward the listener).

So, I think the Skyline is likely the better choice for placing behind your speakers.

Hope this helps!

Tim
Old 5th July 2013 | Show parent
  #268
Gear Addict
 
Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by robertopisa ➡️
I am traveling with an iPad for some days, when back home I will experiment as you suggest. I have some other ideas that I will share as soon as Reflex says OK

Thanks
Roberto
Sounds awesome Roberto. Please let us know how it goes!

Tim
Old 25th August 2013
  #269
Gear Head
 
🎧 5 years
Hi Tim

I have a 6m x 6m metre 2 channel listening room with big horn speakers. Current room treatment is floor to ceiling superchunks and 4 1200x600 100mm thick absorption traps. I want to treat the rear wall with diffusers, what do you suggest, it sit close to the rear wall (1.2metres away) due to large speakers.
Old 25th August 2013 | Show parent
  #270
Lives for gear
 
Mctwins's Avatar
 
🎧 5 years
Quote:
Originally Posted by hornguy ➡️
Hi Tim

I have a 6m x 6m metre 2 channel listening room with big horn speakers. Current room treatment is floor to ceiling superchunks and 4 1200x600 100mm thick absorption traps. I want to treat the rear wall with diffusers, what do you suggest, it sit close to the rear wall (1.2metres away) due to large speakers.
Hallo!

Here is some snapshots of our room (Bobeccas system) with diffusers where you can sit very close and use big horn loudpeakers.



Here, I am sitting aproximately 0,5meters away from the Wingdiffuser.


Last edited by Mctwins; 25th August 2013 at 04:00 PM.. Reason: adding text
📝 Reply

Similar Threads

Thread / Thread Starter Replies / Views Last Post
replies: 1366 views: 1114820
Avatar for chrispire
chrispire 26th March 2021
replies: 2619 views: 475404
Avatar for S21
S21 22nd March 2021
replies: 75 views: 31914
Avatar for massimomucci
massimomucci 11th June 2020
replies: 88 views: 5859
Avatar for TobyB
TobyB 1 day ago
Topic:
Post Reply

Welcome to the Gearspace Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…

Forum Jump
Forum Jump