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DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals)
Old 23rd April 2016 | Show parent
  #661
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🎧 5 years
Quote:
Originally Posted by Pultzar ➡️
Thanks for your analysis Tim!

I am going to be sitting around 12 feet from these diffusers and they won't be visible to me (painted black in a dark theater) so I'm not worried about how they look.

That being said I don't know if the finned designs are better for me or not. As you say they may affect the spatial dispersion. Also we aren't seeing absorption coefficients here. I'm assuming that a fin-less design probably absorbs less?
Yes, Scott, you're right that finless diffusers generally absorb less, but the way you have it (with fins only separating the individual panels) I expect the difference will be negligible. Absorption becomes an issue when we have narrow wells, all separated by fins.

At 12 feet away, any of these diffusers will serve you well, and I think the finned versions would be good as they do extend the bandwidth to lower frequencies.

Your non-symmetrical version has the best random incidence diffusion coefficients, but when trying to create a sweet spot at the listening position a symmetrical rear wall diffuser is the natural choice. If you plan to go with your non-symmetrical version on the rear wall, test it first at the angles your speakers will be firing (e.g. 0 degrees, 30 degrees to either side). If it has lopsided performance, a symmetrical design would be better on the rear wall.
Old 23rd April 2016
  #662
Gear Head
 
🎧 5 years
Good point about symmetry, I think that will be important for me. I had a Model7 which was a slightly different version of Model6 but then my software ran out of memory and could no longer produce results, so I'll have to rebuild it again.

Also I plan on adding the fractal high frequency elements but obviously don't want to model those right now.
Old 23rd April 2016
  #663
Gear Head
 
🎧 5 years
Are people using glue and screws for construction or is glue and a brad nailer sufficient?

Of course just glue would be fine but these are a little tricky to clamp.
Old 24th April 2016 | Show parent
  #664
Gear Head
 
🎧 5 years
Quote:
Originally Posted by Pultzar ➡️
Thanks for sharing! I think I'll model these in a wider array with some depth modulation.
I'm not going to get this thread OT. After doing some modelling lets just say I am stick with leanfuser based designs.
Old 26th April 2016 | Show parent
  #665
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🎧 5 years
Quote:
Originally Posted by Pultzar ➡️
Are people using glue and screws for construction or is glue and a brad nailer sufficient?

Of course just glue would be fine but these are a little tricky to clamp.
You can use just glue for assembling the panels, but the risers for the depth modulations need to be very sturdy and well secured to the wall.

The best construction method I've found so far for is to make risers (basically boxes/cabinets) of the correct depth, with a diffuser panel mounted to the front of the box, and a french cleat built into the back of the box.

This way they can be mounted like this:



For an array of diffusers you can alternatively mount two long french cleat rails on the wall (drilled into the studs), one near the top of the diffuser, one near the bottom. The diffuser modules (risers with panels on the front and french cleats on the back) then get hung onto the rails, like hanging a row of individual cabinets.

Here's an example, except it looks like their bottom rail is just blocking to space the cabinet off the wall, not a french cleat. I'm not sure if it's better to do one cleat rail plus a spacer (like in the attached image), or two cleat rails. Two cleat rails would distribute the load over more area, but you have to very accurate when building them so everything lines up and both rails are actually taking the load (with most of the load hanging on the top rail).



Quote:
Originally Posted by Pultzar ➡️
I'm not going to get this thread OT. After doing some modelling lets just say I am stick with leanfuser based designs.
Don't worry about meandering! Any diffuser designs are worth discussing here and new ideas are always welcome. It's great when people take the initiative to explore.
Attached Thumbnails
DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals)-frenchcleatscreenhangingmethod.jpg  

Last edited by Arqen; 26th April 2016 at 02:05 PM..
Old 30th April 2016
  #666
Gear Head
 
🎧 5 years
Do people have a peference on mdf vs plywood? MDF is about half the price. I'm not concerned about looks but rather how easy it is to work with the materials. Seems like MDF would mill better for the fractal pieces?
Old 13th June 2016 | Show parent
  #667
Gear Nut
 
2 Reviews written
🎧 10 years
Quote:
Originally Posted by Pultzar ➡️
Do people have a peference on mdf vs plywood? MDF is about half the price. I'm not concerned about looks but rather how easy it is to work with the materials. Seems like MDF would mill better for the fractal pieces?
+1 and bump!
Old 14th June 2016 | Show parent
  #668
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🎧 5 years
MDF vs plywood for fractal diffuser

Quote:
Originally Posted by Pultzar ➡️
Do people have a peference on mdf vs plywood? MDF is about half the price. I'm not concerned about looks but rather how easy it is to work with the materials. Seems like MDF would mill better for the fractal pieces?
Good question. MDF is great and I would choose it over plywood in most cases. It's easier to mill and a good density for diffusers.

People sometimes use plywood because they like the aesthetic, or but if you're painting it MDF makes more sense. Especially for a fractal diffuser.
Old 13th July 2016
  #669
Here for the gear
 
🎧 5 years
Cannot download plans

I can't get the plans when I need them. I click the link and it's supposed to send me a confirmation email. It works for the newsletter but not for the plans. Verizon might be blocking the confirmation email? It's not in my spam folder or anywhere else, and Verizon usually sends a notice if it stops something. I wonder whether arqen.com got a 'bounced mail' notice?
Old 13th July 2016 | Show parent
  #670
Here for the gear
 
🎧 5 years
second source for plans?

Is there a second more reliable source for the plans and thesis?
Old 13th July 2016
  #671
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🎧 5 years
My listening room's back wall has two reasonably symmetrical open doorways to the living room thru short hallways. So the living room needs diffusion on its back wall and absorption elsewhere, which also works out well for viewing television there. I figure that any wavefront that makes it thru the doorway will strike the livingroom back wall either directly or thru a bounce. At that point, I could struggle and fail to absorb it all, but I could easily diffuse it and absorb it via the thick treatment over much larger surface area in the livingroom. Those doorways might end up like big portal to a really great trap.
Old 13th July 2016 | Show parent
  #672
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🎧 5 years
Quote:
Originally Posted by cyclecamper ➡️
I can't get the plans when I need them. I click the link and it's supposed to send me a confirmation email. It works for the newsletter but not for the plans. Verizon might be blocking the confirmation email? It's not in my spam folder or anywhere else, and Verizon usually sends a notice if it stops something. I wonder whether arqen.com got a 'bounced mail' notice?
Hi Gregory,

Sorry for the difficulty. I've looked into this. My email software (Aweber) says the confirmation emails were sent to both addresses you provided, at 8:47pm and 9:19pm. I had 22 requests for plans yesterday by other people, and the delivery system was working for them.

However, the three emails you sent me were flagged as spam by my Gmail, so it looks like there's an issue with spam filtering. I've added you to my whitelist, and you should add my email to yours (my first name [at] a word that starts with A dot com) . Instructions for Verizon are here: https://help.aweber.com/hc/en-us/articles/204029246.

It might help to add aweber.com as well, although I'd be surprised if their domain is the issue, as they have very low bounce rates due to their anti-spam policies. I've been using them for a few years and rarely had an issue.

You may have to use a different email address, as Aweber doesn't have a way to re-send the confirmation email unless I wait a few weeks (they have strict regulations like this to ensure that spam laws are not broken).

If it's still not working with my email on your safe list, I can email you the plans manually. But it's better if we get this working for you, as there are some followup emails explaining how to build more complex diffusers.

Cheers,
Tim

Last edited by Arqen; 13th July 2016 at 11:13 AM..
Old 14th July 2016 | Show parent
  #673
Here for the gear
 
🎧 5 years
Quote:
Originally Posted by Arqen ➡️
Hi Gregory,

Sorry for the difficulty. I've looked into this. My email software (Aweber) says the confirmation emails were sent to both addresses you provided, at 8:47pm and 9:19pm. Cheers,
Tim
My daughter and brother both tried it yesterday on my behalf without success, using very different ISPs and email providers. The second address I tried yesterday worked at some time, and I was able to get the documents at work!

What seems strange is that signing up for your newsletter worked fine right away.

Anyway, I love it! This is a great compliment to the absorbers and bass traps I'm building. It makes me wish I had a big shaper or long stack of dado blades or something to just rip a lot of board strips in a pass.
Old 14th July 2016
  #674
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🎧 5 years
scaling psoportions up or down

I expect that it would affect the bandwidth, but can I scale this up or down proportionally to suit the material at-hand?

I'm also very curious about combining absorption with diffusion. Diff-sorber or diffusorber or some such lovely abomination of any pure theory. I imagine it could be very difficult to predict the performance without trial and measurement, and it's a less than ideal hard surface for the diffusor. Still, it might be a decent surface shape for an absorber anyway, and some of these raise the material off the flat surface with a cavity behind some areas.

I guess I'd better go read the last million pages. And I want to thank you sincerely for sharing your knowledge.
Old 14th July 2016 | Show parent
  #675
Here for the gear
 
🎧 5 years
My brother did get the confirmation email. So indeed it might be something with Verizon. Thanks.
Old 15th July 2016 | Show parent
  #676
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🎧 5 years
Quote:
Originally Posted by cyclecamper ➡️
I expect that it would affect the bandwidth, but can I scale this up or down proportionally to suit the material at-hand?

I'm also very curious about combining absorption with diffusion. Diff-sorber or diffusorber or some such lovely abomination of any pure theory. I imagine it could be very difficult to predict the performance without trial and measurement, and it's a less than ideal hard surface for the diffusor. Still, it might be a decent surface shape for an absorber anyway, and some of these raise the material off the flat surface with a cavity behind some areas.

I guess I'd better go read the last million pages. And I want to thank you sincerely for sharing your knowledge.
Glad it's working now.

Yes, you can scale it proportionally, but I suggest you keep the well-width between 3-9 cm (assuming a non-fractal design).

It's harder to predict the performance if the reflective surface is broken up to provide absorption, but it can be made into a device that diffuses mid-high frequencies while absorbing low. E.g., the risers used to lift the diffuser panels off the wall can have absorptive fill to create a quarter-wavelength absorber, or a Helmholtz resonator (the latter is easier said than done).

It's also possible to create a more broadband diffsorber by perforating the surface, but without measurements, it's complex to predict how this will affect the diffusion.
Old 19th July 2016
  #677
Gear Head
 
🎧 5 years
For those of you who have milled your fractal pieces, how long did it take for the routing?

I'm planning on building 13 of these which is 91 fractal pieces. At three cuts each, that is at least 273 trips through the router.

I got a quote for CNC and it is basically the same price as me purchasing an entire router setup (motor, lift, table, fence, etc). I haven't used a router before so I don't know what the feed rate would be. So I'm torn between convenience and having these tools for a future project.
Old 19th July 2016
  #678
Gear Head
 
🎧 5 years
For those of you who have milled your fractal pieces, how long did it take for the routing?

I'm planning on building 13 of these which is 91 fractal pieces. At three cuts each, that is at least 273 trips through the router.

I got a quote for CNC and it is basically the same price as me purchasing an entire router setup (motor, lift, table, fence, etc). I haven't used a router before so I don't know what the feed rate would be. So I'm torn between convenience and having these tools for a future project.
Old 19th July 2016 | Show parent
  #679
Lives for snowflakes
 
12ax7's Avatar
 
🎧 10 years
Quote:
Originally Posted by Pultzar ➡️
For those of you who have milled your fractal pieces, how long did it take for the routing?

I'm planning on building 13 of these which is 91 fractal pieces. At three cuts each, that is at least 273 trips through the router.

I got a quote for CNC and it is basically the same price as me purchasing an entire router setup (motor, lift, table, fence, etc). I haven't used a router before so I don't know what the feed rate would be. So I'm torn between convenience and having these tools for a future project.
But of course you would also gain some knowledge and experience that you do not now possess.

...And I (for one) do not think there's any such thing as useless knowledge.

Also don't forget that even if you decide that you hate everything about using routers, you could always sell those tools if ya decided ya didn't wanna keep 'em.

(It's not like buying a computer or a smartphone.)
.
Old 19th July 2016 | Show parent
  #680
Lives for gear
 
🎧 15 years
Quote:
Originally Posted by 12ax7 ➡️
[INDENT]But of course you would also gain some knowledge and experience that you do not now possess.
But perhaps lose a finger or two along the way... Respect routers...
Old 20th July 2016 | Show parent
  #681
Gear Head
 
🎧 5 years
Quote:
Originally Posted by DPower ➡️
But perhaps lose a finger or two along the way... Respect routers...
Seriously.
Old 20th July 2016 | Show parent
  #682
Gear Addict
 
🎧 10 years
Quote:
Originally Posted by Pultzar ➡️
For those of you who have milled your fractal pieces, how long did it take for the routing?

I'm planning on building 13 of these which is 91 fractal pieces. At three cuts each, that is at least 273 trips through the router.

I got a quote for CNC and it is basically the same price as me purchasing an entire router setup (motor, lift, table, fence, etc). I haven't used a router before so I don't know what the feed rate would be. So I'm torn between convenience and having these tools for a future project.
It`s more than 273 passes, because one cannot take deeper passes than appr 6mm MAX on a router table, I normally take much shallower passes, I use both cnc and router table.

If you are routing it yourself I would advise you to do it outside have a dust collector that is is venting to the outside , there will be lots of fine dust and formaldehyde when using mdf/plywood (less with plywood).

You might be able to get the price of the cnc job down if you offer to do the cleanup of the routed parts yourself, it is very easy to do (remove tabs/onion skin), or you can cut the stock around 5-10mm oversized, in this case the "stock" is the individual fraqtal pieces, this way it can then be routed with perfect edge finish and no cleanup, provided the cnc router has vacuum pods that are small enough.

Last edited by hsal; 20th July 2016 at 06:18 PM..
Old 21st July 2016 | Show parent
  #683
Gear Head
 
🎧 5 years
Quote:
Originally Posted by hsal ➡️
It`s more than 273 passes, because one cannot take deeper passes than appr 6mm MAX on a router table, I normally take much shallower passes, I use both cnc and router table.

If you are routing it yourself I would advise you to do it outside have a dust collector that is is venting to the outside , there will be lots of fine dust and formaldehyde when using mdf/plywood (less with plywood).

You might be able to get the price of the cnc job down if you offer to do the cleanup of the routed parts yourself, it is very easy to do (remove tabs/onion skin), or you can cut the stock around 5-10mm oversized, in this case the "stock" is the individual fraqtal pieces, this way it can then be routed with perfect edge finish and no cleanup, provided the cnc router has vacuum pods that are small enough.
Good to know. Hiring a CNC is quickly approaching the top of my list!
Old 17th August 2016 | Show parent
  #684
0N3
Here for the gear
 
🎧 10 years
Routing by hand will no doubt prove difficult and time consuming.

I think a good solution is to just rip furring strips. Rip them to near exact width (8.6mm), then rip them in steps (11.4 20 17 22.8 14.3 2.9). Then just place them side by side in the correct order on top of another furring strip with a width of 60mm. Make 7 of those, place 6 of them on additional furring strips with a width of 60mm and the corresponding depth.

You may want to router 6 small notches (a few millimeters) length wise on the base plate, located at the center of each strip so when you glue them you won't need to worry about expansion. Use as little glue as possible, it doesn't take much.

A CNC would be nice though, you would need a large scale CNC. It would be near EXACT

Routing by hand isn't the right choice. If its a router that cuts it, let it be a CNC.

Last edited by 0N3; 17th August 2016 at 05:42 AM..
Old 19th August 2016
  #685
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🎧 5 years
The most efficient way to mill them is with a wood shaper using a custom knife. Of course, getting the knife made isn't cheap, but if you had to do a big batch it would save a lot of man hours.
Old 19th August 2016
  #686
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🎧 5 years
Just went on a precision cutter porn spree.

What is this emotion I'm feeling?

Old 26th August 2016 | Show parent
  #687
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Electrisizer's Avatar
 
🎧 15 years
hello ive built the b2 diffractal. you can see it on photo attached. the fractals are only layed against the constuction i want to lacquer the constuction first and leave the fractals natural...

the fractal wood is spruce. i would have better used harder wood like oak. the mills are not that perfect with soft wood. perhaps ill build another one with oak


my question is: has somebody tested the fractal diffuser on a control rooms back wall? i need some diffuser in my control room and in my recording room too. so theres the question, is the fractal diffuser the best choice in both rooms?
Attached Thumbnails
DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals)-b2-diff.jpg  
Old 26th August 2016 | Show parent
  #688
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Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by Electrisizer ➡️
hello ive built the b2 diffractal. you can see it on photo attached. the fractals are only layed against the constuction i want to lacquer the constuction first and leave the fractals natural...

the fractal wood is spruce. i would have better used harder wood like oak. the mills are not that perfect with soft wood. perhaps ill build another one with oak


my question is: has somebody tested the fractal diffuser on a control rooms back wall? i need some diffuser in my control room and in my recording room too. so theres the question, is the fractal diffuser the best choice in both rooms?
Looks great. The Leanfractal (A1-Frac) has been used on the rear wall of several control rooms with good results. I haven't seen any real world tests with the B2 fractal diffuser on the rear wall, but A1-Frac would be better there provided it's mounted as recommended (using the recommended profiled modulations), due to its left-right symmetry and increased operational depth.

I'm heading off on holidays this morning, so if you have specific questions about building the Leanfractal (A1-Frac), shoot me an email after Sept 1st. If there's a big delay in me responding, it's because I'm off the grid .
Old 26th August 2016 | Show parent
  #689
0N3
Here for the gear
 
🎧 10 years
Quote:
Originally Posted by Arqen ➡️
Just went on a precision cutter porn spree.

What is this emotion I'm feeling?

This video is amazing!

It is the awesome power and precision of heavy cutting machinery, cuts aluminum like butter. I got bit by this emotion a few years back and ended up buying a lathe and mill and converting them into cnc's, I ended up learning AutoCAD Inventor + Mach3 to control them. Awesome stuff, and you can do amazing things. My two favorite things in life (Writing music and inventing things) both very expensive, but even more so fulfilling.

Sorry* back to the Leanfractals :D
Old 28th August 2016 | Show parent
  #690
Gear Nut
 
Electrisizer's Avatar
 
🎧 15 years
Quote:
Originally Posted by Arqen ➡️
Looks great. The Leanfractal (A1-Frac) has been used on the rear wall of several control rooms with good results. I haven't seen any real world tests with the B2 fractal diffuser on the rear wall, but A1-Frac would be better there provided it's mounted as recommended (using the recommended profiled modulations), due to its left-right symmetry and increased operational depth.
hello tim, thanks for the answer and your great DIY encourage

wich profiled modulation would you recommend? my back wall is after acustic treatment (absorber) 77cm deep it was the only way to get a good bass treatment in the control room (lenght = 5.60m). now my bass SPL is flat but my room is contracted a not sooo deep diffuser would be preferable, compomising performance vs room size.

my listening position is about 2.50m from absorber treated back wall
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