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DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals)
Old 10th August 2014 | Show parent
  #481
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Arqen's Avatar
 
🎧 5 years
Quote:
Originally Posted by blizt ➡️
I painted them with a water based sealer and now I'm thinking leaving them like that. I kind of like the unfinished touch. What do you think?
Quote:
Originally Posted by ellisr63 ➡️
I think it looks good... It gives it the white washed antique look.

Looks good. Not suggesting you do this but I recently saw a video by Adam Savage about how to make things look weathered / antique:

One Day Builds: Adam Savage Demonstrates Weathering Tricks - YouTube

Total overkill in most cases, but in this case he was weathering his custom built microscope box so that it "tells a story".
.
Old 11th August 2014
  #482
Gear Head
 
🎧 5 years
Hi Tim
I am thinking of building A1 LF modules to treat the rear wall between the corner bass traps, a width of 4700mm, in addition to front and ceiling reflection points. What depth profile would you recommend without going crazy deep?
In addition for such a large build, which would require a rigid timber to hold the panels in place, I will probably delete the 420 wide rear piece and just use a 90mm wide piece of mdf on either side, relying on 2 or 3 horizontal pieces of timber.

Thanks for the design
Old 11th August 2014
  #483
Gear Head
 
🎧 5 years
Hi Tim
I am thinking of building A1 LF modules to treat the rear wall between the corner bass traps, a width of 4700mm, in addition to front and ceiling reflection points. What depth profile would you recommend without going crazy deep?
In addition for such a large build, which would require a rigid timber to hold the panels in place, I will probably delete the 420 wide rear piece and just use a 90mm wide piece of mdf on either side, relying on 2 or 3 horizontal pieces of timber.

Thanks for the design
Attached Thumbnails
DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals)-ai-lf.jpg  
Old 15th August 2014 | Show parent
  #484
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🎧 5 years
Quote:
Originally Posted by hornguy ➡️
Hi Tim
I am thinking of building A1 LF modules to treat the rear wall between the corner bass traps, a width of 4700mm, in addition to front and ceiling reflection points. What depth profile would you recommend without going crazy deep?
In addition for such a large build, which would require a rigid timber to hold the panels in place, I will probably delete the 420 wide rear piece and just use a 90mm wide piece of mdf on either side, relying on 2 or 3 horizontal pieces of timber.

Thanks for the design
Hi Gregg,

Great question.

To arrange 11 modules I recommend using the 7-panel fractal modulation in the center, and a 3 panel modulation on either side.
3+7+3 = 13, but two of the zero-depth panels can be shared / superimposed, bringing the total panels to 11.

It sounds a bit confusing so here's what I mean. The overall depth profile for mounting the 11 panels would be:

[0, 7, 0, 8, 10, 6, 10, 8, 0, 7, 0] cm

This seamlessly blends three performance-tested diffuser arrays and it maintains left-right symmetry.
It works out very nicely!
Old 18th August 2014 | Show parent
  #485
Here for the gear
 
🎧 5 years
Minor modification to Leanfuser 2 panel array

Hi Everyone

Just wanted to share my experience with a 2 panel lean fuser array that I mounted on a narrow structural wall.

Before mounting the panels permanently, it occurred to me that I could leave a small gap between the 2 panels, thus creating an additional diffusion channel. The wall being narrow (86 cm wide, as compared to a 2 panel array of 84cm wide (42cm x 2)), I ended up with a gap of 7 mm between panels. The total width of array is now 84.7cm. There was a significant improvement in the sound for only a small increase in the width of the array.

I cannot say that you would have an improvement if you leave gaps between panels but it could be well worth a try. I would be interested to hear on your experiences with simiar experiments.

For completeness, and based on earlier posts, I mounted 1 panel flush against the wall and the next panel 12mm away from the wall. I am using 12mm MDF, so that was easiest while maintaining a ‘lean’ profile.
Old 21st August 2014 | Show parent
  #486
Here for the gear
 
🎧 5 years
Fractal increments question

Hi Tim

I am thinking of adding fractal cells to my Leanfusers but have a question caused by the thickness of pine in Australia. We don't have pine with a thickness of 14mm or in multiples thereof.

So, if I were to use pine of 19mm thickness, do I merely increase the well depths proportionately? To state the question in greater length, in the FAQs to the Argen website, you suggest that fractal cells could be [0, 11, 14, 8, 14, 11, 0] mm or doubled to [0, 22, 28, 17, 28, 22, 0] mm. As the pine I am proposing to use is 19mm thick, I would propose to mill fractal cells of [0, 15, 19, 11, 19, 15, 0] mm. Hence I would be applying a multiplier of 1.357 to the proposed [0, 11, 14, 8, 14, 11 0] rather then a multiplier of 2. Do you have any concerns or advice about this variation?

Would it be better for me to go with [0, 16, 19, 13, 19, 16, 0] mm? This is [0, 11, 14, 8, 14, 11 0] increased by 5mm.

Thanks again for all your help.

Shannon
Old 21st August 2014 | Show parent
  #487
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🎧 5 years
Quote:
Originally Posted by Woodear ➡️
Hi Everyone

Just wanted to share my experience with a 2 panel lean fuser array that I mounted on a narrow structural wall.

Before mounting the panels permanently, it occurred to me that I could leave a small gap between the 2 panels, thus creating an additional diffusion channel. The wall being narrow (86 cm wide, as compared to a 2 panel array of 84cm wide (42cm x 2)), I ended up with a gap of 7 mm between panels. The total width of array is now 84.7cm. There was a significant improvement in the sound for only a small increase in the width of the array.

I cannot say that you would have an improvement if you leave gaps between panels but it could be well worth a try. I would be interested to hear on your experiences with simiar experiments.

For completeness, and based on earlier posts, I mounted 1 panel flush against the wall and the next panel 12mm away from the wall. I am using 12mm MDF, so that was easiest while maintaining a ‘lean’ profile.
Interesting that there was a significant improvement with such a small gap. I can speculate on a few reasons why the response could improve but I'm surprised that it's so noticeable. Thanks for sharing this.
Old 21st August 2014 | Show parent
  #488
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🎧 5 years
Quote:
Originally Posted by Woodear ➡️
Hi Tim

I am thinking of adding fractal cells to my Leanfusers but have a question caused by the thickness of pine in Australia. We don't have pine with a thickness of 14mm or in multiples thereof.

So, if I were to use pine of 19mm thickness, do I merely increase the well depths proportionately? To state the question in greater length, in the FAQs to the Argen website, you suggest that fractal cells could be [0, 11, 14, 8, 14, 11, 0] mm or doubled to [0, 22, 28, 17, 28, 22, 0] mm. As the pine I am proposing to use is 19mm thick, I would propose to mill fractal cells of [0, 15, 19, 11, 19, 15, 0] mm. Hence I would be applying a multiplier of 1.357 to the proposed [0, 11, 14, 8, 14, 11 0] rather then a multiplier of 2. Do you have any concerns or advice about this variation?

Would it be better for me to go with [0, 16, 19, 13, 19, 16, 0] mm? This is [0, 11, 14, 8, 14, 11 0] increased by 5mm.

Thanks again for all your help.

Shannon
Logically you would increase the well depths proportionally. In practice, however, the performance tends to increase simply by scaling up the well depths. This is because the rougher the surface, the more it tends to scatter (and absorb).

I would stick with a scalar (e.g., x 1.357) rather than + 5mm. We know that the base shape has great performance, and while testing other base units (using 12.7 mm material instead of 10 mm) I've confirmed that it has a slightly better performance when the depths are scaled up by a factor of 1.27. This it probably mostly due to the increase in height / roughness, but it's worth considering that scaling (even if only the height is scaled) preserves some of the general characteristics of the optimized shape.

It may not matter performance wise but I consider [0, 15, 19, 11, 19, 15, 0] mm to be a closer cousin to the optimized shape than [0, 16, 19, 13, 19, 16, 0].

You might also try sketching a 19 mm x 2 scaled fractal on paper to see if it looks ridiculously s***** or fragile. If it looks practical and durable enough it might be something to consider. The absorption would increase, but intuitively I expect it would provide a boost in high frequency diffusion performance.

Good luck with this project!

-Tim

P.S. I'm heading on a backpacking trip tomorrow so I may not have internet access till mid next week. If you have more questions I'll reply to them after I return.
Old 22nd August 2014 | Show parent
  #489
Here for the gear
 
🎧 5 years
Minor modification to 2 panel leanfuser

Quote:
Originally Posted by Arqen ➡️
Interesting that there was a significant improvement with such a small gap. I can speculate on a few reasons why the response could improve but I'm surprised that it's so noticeable. Thanks for sharing this.
Hi Tim

Hope you have a good time in the Canadian wilds (?).

I was also quite surprised by the improvement for such a minor modification. Perhaps the improvement comes more from the increase in the operational depth of the panels rather than the addition of a narrow channel. It may be that the operational depth of the panel that is mounted directly on the wall increases by 20 per cent (a depth of five panels becomes six) and the operational depth of the panel that is mounted 12 mm from the wall increases by 16 per cent (a depth of six panels becomes seven).

Shannon
Old 26th August 2014 | Show parent
  #490
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🎧 5 years
Quote:
Originally Posted by Woodear ➡️
Hi Tim

Hope you have a good time in the Canadian wilds (?).

I was also quite surprised by the improvement for such a minor modification. Perhaps the improvement comes more from the increase in the operational depth of the panels rather than the addition of a narrow channel. It may be that the operational depth of the panel that is mounted directly on the wall increases by 20 per cent (a depth of five panels becomes six) and the operational depth of the panel that is mounted 12 mm from the wall increases by 16 per cent (a depth of six panels becomes seven).

Shannon
Thanks Shannon,

Yes, I had a great time backpacking in Strathcona Park on Vancouver Island!

You're almost certainly right: the improvement is probably caused by an increase in operational depth, but I'm not sure how mounting it directly on the wall increases the operational depth. I think I misunderstood how you mounted it.

Does one of the panels have no base, so that the diffuser consists of 5 strips/steps/"wells" fixed to the wall? I.e., the base of the diffuser is simply the wall surface?

Like this:
wall-4-5-3-5-4-wall ?
Old 2nd September 2014 | Show parent
  #491
Here for the gear
 
🎧 5 years
Minor modification to 2 panel leanfuser

Quote:
Originally Posted by Arqen ➡️
Thanks Shannon,

Yes, I had a great time backpacking in Strathcona Park on Vancouver Island!

You're almost certainly right: the improvement is probably caused by an increase in operational depth, but I'm not sure how mounting it directly on the wall increases the operational depth. I think I misunderstood how you mounted it.

Does one of the panels have no base, so that the diffuser consists of 5 strips/steps/"wells" fixed to the wall? I.e., the base of the diffuser is simply the wall surface?

Like this:
wall-4-5-3-5-4-wall ?

Actually both panels were built as per your blueprints (backpanel-4-5-3-5-4- backpanel). As viewed from the side before mounting, there are 6 layers of MDF, each 12 mm thick. The backpanel itself is 42cm wide.

When mounting, one panel had an addtional MDF layer of 12mm thick placed behind it. Hence that panel is effectively 7 layers thick.

The other panel was mounted directly onto the wall.

As an aside, I describe this additional layer as I tried a bass trap experiment, inpired by an earlier post (yours, I think) about attempting to construct a bass trap within the leanfuser. The experiment though interesting, proved deleterious. To save on weight and materials, that layer was constructed as a 'picture frame' rather than as one solid sheet. The sides of the frame were 8 cm thick so as to make the backpanel of 42 cm less resonant. Hence there is a narrow but wide cavity running the length of the panel.

Initially I sealed only the bottom of the panel and not the top. I should add that the each panels consists of 2 panels, 1 placed on top of the other. The total height of each '2 panel' panel is 246cm. Hence the cavity at the back is 246 cm long and forms a crude Helmholtz resonator. Being sealed at one end, the resonant frequency is 35Hz. As my room has a bass peak between 34 and 36 Hz, I thought the resonance would help dissipate some of the bass energy at that frequency. Alas that did not work and so I have sealed the top of the cavity. I note that I use piping as Helmholz resonators to control base bumps but for some reason, it did not work as part of the Leanfuser. Perhaps the Leanfuser resonator ends too close to my ceiling ...

Last edited by Woodear; 2nd September 2014 at 08:30 AM.. Reason: to improve clarity of the post
Old 2nd September 2014 | Show parent
  #492
Here for the gear
 
🎧 5 years
Are fractal cells worth the effort? YES!

Quote:
Originally Posted by Arqen ➡️
Logically you would increase the well depths proportionally. In practice, however, the performance tends to increase simply by scaling up the well depths. This is because the rougher the surface, the more it tends to scatter (and absorb).

I would stick with a scalar (e.g., x 1.357) rather than + 5mm. We know that the base shape has great performance, and while testing other base units (using 12.7 mm material instead of 10 mm) I've confirmed that it has a slightly better performance when the depths are scaled up by a factor of 1.27. This it probably mostly due to the increase in height / roughness, but it's worth considering that scaling (even if only the height is scaled) preserves some of the general characteristics of the optimized shape.

It may not matter performance wise but I consider [0, 15, 19, 11, 19, 15, 0] mm to be a closer cousin to the optimized shape than [0, 16, 19, 13, 19, 16, 0].

You might also try sketching a 19 mm x 2 scaled fractal on paper to see if it looks ridiculously s***** or fragile. If it looks practical and durable enough it might be something to consider. The absorption would increase, but intuitively I expect it would provide a boost in high frequency diffusion performance.

Good luck with this project!

-Tim

P.S. I'm heading on a backpacking trip tomorrow so I may not have internet access till mid next week. If you have more questions I'll reply to them after I return.
Was wondering why you were wishing me luck on the project and then I started routing the channels for the fractal cells ... thanks as I will need it!
Its a big job for a newbie carpenter. Fortunately I had the sense to buy a router table; other novice carpenters should consider investing in one too.

I should add that after some experimentation with my router and table, I only had time to cut the centre channels for 7 cells (enough for 1 leanfuser panel). The weekend rolled by and I bluetacked the semi complete cells on one of the panels of my 2 panel array, described in my earlier posts (the one mounted further from the wall). Even though only 1 groove was routed, the cells are functionally 3/5th complete. The improvement was clear and it was enough to convince me of the merits of proceeding with the rest of the project.

Readers who wonder if the fractal cells are worth the effort could merely blue tack wood of appropriate width to their leanfusers. In Australia, pine of 42mm width is common. Even if no routing or milling is done, bluetacked strips of pine constitute fractal cell that I believe are functionally 2/5th complete and will give readers a taste for what might be.

Anyway I have since routed enough centre channels cells for 7 leanfuser panels (I also have a 5 panel array) and the blue tacked results are extremely positive. I will definitely rout the shoulders off the cells to complete the project.
Old 3rd September 2014 | Show parent
  #493
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🎧 5 years
Quote:
Originally Posted by Woodear ➡️
Actually both panels were built as per your blueprints (backpanel-4-5-3-5-4- backpanel). As viewed from the side before mounting, there are 6 layers of MDF, each 12 mm thick. The backpanel itself is 42cm wide.

When mounting, one panel had an addtional MDF layer of 12mm thick placed behind it. Hence that panel is effectively 7 layers thick.

The other panel was mounted directly onto the wall.

As an aside, I describe this additional layer as I tried a bass trap experiment, inpired by an earlier post (yours, I think) about attempting to construct a bass trap within the leanfuser. The experiment though interesting, proved deleterious. To save on weight and materials, that layer was constructed as a 'picture frame' rather than as one solid sheet. The sides of the frame were 8 cm thick so as to make the backpanel of 42 cm less resonant. Hence there is a narrow but wide cavity running the length of the panel.

Initially I sealed only the bottom of the panel and not the top. I should add that the each panels consists of 2 panels, 1 placed on top of the other. The total height of each '2 panel' panel is 246cm. Hence the cavity at the back is 246 cm long and forms a crude Helmholtz resonator. Being sealed at one end, the resonant frequency is 35Hz. As my room has a bass peak between 34 and 36 Hz, I thought the resonance would help dissipate some of the bass energy at that frequency. Alas that did not work and so I have sealed the top of the cavity. I note that I use piping as Helmholz resonators to control base bumps but for some reason, it did not work as part of the Leanfuser. Perhaps the Leanfuser resonator ends too close to my ceiling ...
Ah, I understand how you mounted them now. I think the performance increase is mostly due to two things:
1) The extra depth of the 7 layer thick panel.
2) Since the panels are at different depths there is a small profiled modulation. This reduces undesirable periodic effects (namely, acoustic lobing) that occur when two or more panels are mounted side by side at the same depth.

It's great to hear that you tried the Helmholtz resonator concept and it's too bad it did not work. It can be tricky to get Helmholtz resonators to work properly. Thanks for sharing your insights on this!
Old 3rd September 2014 | Show parent
  #494
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🎧 5 years
Quote:
Originally Posted by Woodear ➡️
Was wondering why you were wishing me luck on the project and then I started routing the channels for the fractal cells ... thanks as I will need it!
Its a big job for a newbie carpenter. Fortunately I had the sense to buy a router table; other novice carpenters should consider investing in one too.

I should add that after some experimentation with my router and table, I only had time to cut the centre channels for 7 cells (enough for 1 leanfuser panel). The weekend rolled by and I bluetacked the semi complete cells on one of the panels of my 2 panel array, described in my earlier posts (the one mounted further from the wall). Even though only 1 groove was routed, the cells are functionally 3/5th complete. The improvement was clear and it was enough to convince me of the merits of proceeding with the rest of the project.

Readers who wonder if the fractal cells are worth the effort could merely blue tack wood of appropriate width to their leanfusers. In Australia, pine of 42mm width is common. Even if no routing or milling is done, bluetacked strips of pine constitute fractal cell that I believe are functionally 2/5th complete and will give readers a taste for what might be.

Anyway I have since routed enough centre channels cells for 7 leanfuser panels (I also have a 5 panel array) and the blue tacked results are extremely positive. I will definitely rout the shoulders off the cells to complete the project.
Haha, yes, milling the fractals is no small job :-). The level of effort required takes a big jump when you move from the basic Leanfuser design to the Leanfractal!

Good suggestion for a simplified "fractal" version. We can expect any increase to the roughness of the surfaces to increase high frequency scattering, so it's not necessary to go full fractal to get benefits. It would be interesting to compare the performance of the full fractal vs the 3/5th complete fractal (with only one groove routed).

Thanks again for your findings!
Old 16th September 2014 | Show parent
  #495
Gear Head
 
🎧 5 years
Goin back in....

Well, I said one day I'd make the front wall of my listening room consist entirely of stepped diffusers in a 7-module profiled sequence, so this past weekend I started getting things underway. Here are the three center modules (10, 6, 10) mocked up and ready to be assembled. The two outboard modules (0 and 0) are already built and up on the wall and will be moved to their proper positions in the array. The center module on the wall will contribute to building modules 8 and 8. The outboard QRD's will be relocated to the rear sides, flanking the listening position.

- Michael
Attached Thumbnails
DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals)-photo.jpg  
Old 16th September 2014 | Show parent
  #496
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🎧 5 years
7-Panel Diffuser Profiled Modulation Construction

Quote:
Originally Posted by tinnitusintx ➡️
Well, I said one day I'd make the front wall of my listening room consist entirely of stepped diffusers in a 7-module profiled sequence, so this past weekend I started getting things underway. Here are the three center modules (10, 6, 10) mocked up and ready to be assembled. The two outboard modules (0 and 0) are already built and up on the wall and will be moved to their proper positions in the array. The center module on the wall will contribute to building modules 8 and 8. The outboard QRD's will be relocated to the rear sides, flanking the listening position.

- Michael
Great, Michael! Thanks for sharing your build process for the 7-module array. It sounds like you have a good plan for the tricky part of the build: getting all the diffuser panels on the wall at the right depth.

I look forward to seeing how it comes together!
Old 20th September 2014 | Show parent
  #497
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1 Review written
🎧 10 years
after 2 month of building slowly it`s done and sounds fantastic
thanx to tim
Attached Thumbnails
DIY Sound Diffusers—Free Blueprints—Slim, Optimized DIY Diffuser Designs (+Fractals)-030gringo_studioeinweihung14_karinlohbergerphotography.jpg  
Old 20th September 2014 | Show parent
  #498
Gear Head
 
🎧 5 years
^^^

That looks great!

How far behind the listening position to you have your array?

And tell me a little about your ceiling treatments, please....

- Michael
Old 21st September 2014 | Show parent
  #499
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🎧 5 years
Quote:
Originally Posted by AUDIOBOMBER ➡️
after 2 month of building slowly it`s done and sounds fantastic
thanx to tim
Looks fantastic!

Also, Michael (tinnitusintx) asked a good question.

Do you notice any phasey sounding distortions when listening to it that close? At that distance it looks like some frequencies may not have enough space to disperse before you hear them.

In the past, based on guidelines for QRD diffusers, I recommended a listening distance of about 3 times the longest wavelength diffused (for your diffuser build, about 9'-8"). But honestly, people have used them much closer without hearing distortions.

Now I'm thinking you're probably fine at half that distance (about 4 1/2 feet). Any closer than 3 feet and there simply is not enough space for the low end frequencies to form, so I would expect distortions.

Great work on your build and thanks for sharing it!
Old 22nd September 2014
  #500
Here for the gear
 
🎧 5 years
Hi all,

I've been reading up on this since I'm building the acoustic treatment for my home studio. We built a room from scratch at roughly 9.5'w x 19'L x 10'h.

My acoustics engineer designed membrane tuned bass traps as well as recommended covering 60% of the back wall with diffusers and recommended the Arqen diffusers as an excellent DIY option.

I'm just wondering about dimensions regarding the size of my back wall. I'd be using imperial dimensions which, from what I've read, seems to not be a problem when using 1/2" steps. But, if my calculations are correct, my wall can barely fit them. Also, to fulfill the 60% recommendation, I would need to build a longer array (6'?).

Any ideas on how to proceed?
Old 22nd September 2014
  #501
Here for the gear
 
🎧 5 years
Hi all,

I've been reading up on this since I'm building the acoustic treatment for my home studio. We built a room from scratch at roughly 9.5'w x 19'L x 10'h.

My acoustics engineer designed membrane tuned bass traps as well as recommended covering 60% of the back wall with diffusers and recommended the Arqen diffusers as an excellent DIY option.

I'm just wondering about dimensions regarding the size of my back wall. I'd be using imperial dimensions which, from what I've read, seems to not be a problem when using 1/2" steps. But, if my calculations are correct, my wall can barely fit them. Also, to fulfill the 60% recommendation, I would need to build a longer array (6'?).

Any ideas on how to proceed?
Old 23rd September 2014 | Show parent
  #502
Gear Addict
 
1 Review written
🎧 10 years
Quote:
Originally Posted by Arqen ➡️
Looks fantastic!

Also, Michael (tinnitusintx) asked a good question.

Do you notice any phasey sounding distortions when listening to it that close? At that distance it looks like some frequencies may not have enough space to disperse before you hear them.

In the past, based on guidelines for QRD diffusers, I recommended a listening distance of about 3 times the longest wavelength diffused (for your diffuser build, about 9'-8"). But honestly, people have used them much closer without hearing distortions.

Now I'm thinking you're probably fine at half that distance (about 4 1/2 feet). Any closer than 3 feet and there simply is not enough space for the low end frequencies to form, so I would expect distortions.

Great work on your build and thanks for sharing it!
my working/listening place is about 10 feet from the back wall. have not realized any distortion on the couch - will have to investigate. the ceiling cloud is also self-made - simple wood frame with basotek/rock-wool covered with fabric - distance from ceiling around 2.5 feet. you can find more pics here :

https://www.facebook.com/alexander.j...5201363&type=1
Old 24th September 2014 | Show parent
  #503
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🎧 5 years
Quote:
Originally Posted by solersystem ➡️
Hi all,

I've been reading up on this since I'm building the acoustic treatment for my home studio. We built a room from scratch at roughly 9.5'w x 19'L x 10'h.

My acoustics engineer designed membrane tuned bass traps as well as recommended covering 60% of the back wall with diffusers and recommended the Arqen diffusers as an excellent DIY option.

I'm just wondering about dimensions regarding the size of my back wall. I'd be using imperial dimensions which, from what I've read, seems to not be a problem when using 1/2" steps. But, if my calculations are correct, my wall can barely fit them. Also, to fulfill the 60% recommendation, I would need to build a longer array (6'?).

Any ideas on how to proceed?
Welcome to the forum!

Have you considered mounting 5 diffuser panels using Profiled Modulation 1? You could make the panels a bit more narrow than in my original design so that they can be mounted 16" on center (make them 16" wide instead of 420 mm) .

With 5 modules:
5x16" = 80"= 6'-8" wide.

That would cover about 70% of the width of your wall.

Would that work?
Old 24th September 2014 | Show parent
  #504
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🎧 5 years
Quote:
Originally Posted by AUDIOBOMBER ➡️
my working/listening place is about 10 feet from the back wall. have not realized any distortion on the couch - will have to investigate. the ceiling cloud is also self-made - simple wood frame with basotek/rock-wool covered with fabric - distance from ceiling around 2.5 feet. you can find more pics here :

https://www.facebook.com/alexander.j...5201363&type=1
That's a good distance for your listening position.
Your room looks great, by the way!
Old 27th September 2014
  #505
Here for the gear
 
🎧 5 years
Hi again!

Thanks! I've been learning so many other things here. Specially looking at the photos people are posting about their DIY projects. *plays A Whole New World*

To make them narrower, I would have to modify the step width, correct?

Also, it would cover the 70% width of the back wall, but I would like it to cover the back wall area.
Can I just build another "row" of diffusers to make it longer?

Does doing this even make sense in terms of functionality? These are acoustic recommendations by an engineer that worked with me on the acoustic treatment design, but I wonder if it will make that much of an improvement.
Old 30th September 2014
  #506
Gear Head
 
🎧 5 years
Hi Tim

I have access to about 150 M² of engineered timber flooring. It is about 14mm think and is of a plywood type construction with a poor quality timber veneer. What are your thought on using it to build B2 Fratal modules? I would be able to cut the boards to a determined width and build them up to get the fractal design.
Thoughts?
Old 30th September 2014 | Show parent
  #507
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🎧 5 years
16" wide diffuser panels

Quote:
Originally Posted by solersystem ➡️
Hi again!

Thanks! I've been learning so many other things here. Specially looking at the photos people are posting about their DIY projects. *plays A Whole New World*

To make them narrower, I would have to modify the step width, correct?

Also, it would cover the 70% width of the back wall, but I would like it to cover the back wall area.
Can I just build another "row" of diffusers to make it longer?

Does doing this even make sense in terms of functionality? These are acoustic recommendations by an engineer that worked with me on the acoustic treatment design, but I wonder if it will make that much of an improvement.
It would be a very slight modification to the step width. You would reduce the width of each step by about 1/16", so that each step is about 2 5/16" wide.

If you cut the base to be exactly 16" wide and cut all the strips to be 2 5/16" everything should fit quite nicely.

When you mention another row of diffusers, how many panels would that be? I.e., in total, how many 16" wide panels would you like to fit on your wall?

I'm not sure if you're referring to increasing the height (by adding another another row on top), or increasing the width (by adding additional panels). The height is flexible and can certainly be increased if needed.
Old 30th September 2014 | Show parent
  #508
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🎧 5 years
Quote:
Originally Posted by hornguy ➡️
Hi Tim

I have access to about 150 M² of engineered timber flooring. It is about 14mm think and is of a plywood type construction with a poor quality timber veneer. What are your thought on using it to build B2 Fratal modules? I would be able to cut the boards to a determined width and build them up to get the fractal design.
Thoughts?
I would consider the A1-Fractal diffuser instead of B2-Fractal, for reasons discussed here.

Would you be using 14 mm as the basic depth unit? If so, I would scale the widths up proportionally. We know (based on simulations and listener feedback) that it performs well with 1/2" (12.7 mm) material. So, if you're using 14 mm material as the basic depth unit you would ideally scale all well widths by a factor of 14mm/12.7mm = 1.1.

I expect it will still perform well if you don't do this scaling, but I have no test data to support this. The safe way to go is to build it so that the proportions are the same as a verified, tested design.
Old 2nd October 2014 | Show parent
  #509
Gear Head
 
🎧 5 years
Hey Tim....since I'm building the seven module fractal array four of those modules will have air gaps from 3.5" to 4.5" between the wall and the "0" well (or base plate). If you look at the attachment I provided a few posts back that shows the mockup of three modules you can see the 4.5" air gap in the two outboard modules as they lay. The two modules that will be situated outboard of those will have a 3.5" air gap. Should I fill this air gap with something absorptive like rock wool or compressed fiberglass?

Thanks,
Michael
Old 3rd October 2014 | Show parent
  #510
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🎧 5 years
Broadband absorption behind diffusers

Quote:
Originally Posted by tinnitusintx ➡️
Hey Tim....since I'm building the seven module fractal array four of those modules will have air gaps from 3.5" to 4.5" between the wall and the "0" well (or base plate). If you look at the attachment I provided a few posts back that shows the mockup of three modules you can see the 4.5" air gap in the two outboard modules as they lay. The two modules that will be situated outboard of those will have a 3.5" air gap. Should I fill this air gap with something absorptive like rock wool or compressed fiberglass?

Thanks,
Michael
Hey Michael,

Yes, I think that would be a good idea to ensure the hollow structure does not cause any anomalies due to internal reflections. It would also provide a bit of lower mid frequency absorption, just below the diffusion cutoff frequency, although I don't know if you will notice the effects because the diffuser surface itself may be mostly reflective at those frequencies.
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