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December 07, 2021, 09:39:44 AM

Author Topic: quadratic diffuser  (Read 617 times)

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Offline debk

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quadratic diffuser
« on: January 21, 2021, 02:54:01 PM »
In anticipation of building my Jagers, I just spent a few hours trying to understand the felt quadratic diffuser.  As I understand it, the inner pattern looks like a N19 pattern.  If I measure the cells I could calculate the frequencies it is designed for.  There are online calculators for this type of design.
I am baffled by the function and design of the outside part of felt. I would appreciate any help or references to understand the design

Thanks

Debra
Debra K

Eros 2Phono amp
BeePre2, Psvane ACME 300b
Kaiju, Linlai Elite  300b
Monamour 2a3 amps various tubes
Sota Sapphire, Pete Riggle Woody Tonearm, Kiseki Purpleheart Cartridge
Rega P6 Ania Pro cartridge
Roon Nucleus
MHDT Labs Orchid DAC
Jager speakers

Offline Doc B.

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Re: quadratic diffuser
« Reply #1 on: January 21, 2021, 03:50:25 PM »
It's been a few years now since I ran the math and I'm afraid I don't remember the frequency band or the calculator I used. The inside edge is a 2D diffuser pattern. The outside edge is a 3D diffuser pattern. I picked some of the cut felt out of the trash (the stuff smells like burnt hair) I was able to measure the steps at about 10mm. And that top layer is approx. 7 to 8mm thick.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline debk

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Re: quadratic diffuser
« Reply #2 on: January 21, 2021, 05:07:41 PM »
Thanks, the 2d pattern design is understandable.  I need to do a lot more reading to understand the 3d patterns.

For some strange reason I find this topic fascinating.
Debra K

Eros 2Phono amp
BeePre2, Psvane ACME 300b
Kaiju, Linlai Elite  300b
Monamour 2a3 amps various tubes
Sota Sapphire, Pete Riggle Woody Tonearm, Kiseki Purpleheart Cartridge
Rega P6 Ania Pro cartridge
Roon Nucleus
MHDT Labs Orchid DAC
Jager speakers

Offline Doc B.

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Re: quadratic diffuser
« Reply #3 on: January 22, 2021, 05:39:01 AM »
My terminology is bogus. The inside edge is 1D and the outside edge is 2D. Look for a copy of the Master Handbook of Acoustics. It covers quadratic diffusers and it's an excellent resource on room tuning. And of course there are online calculators like I used, and also apps. I probably have some hand scrawled notes somewhere but I have no idea where to start looking. Might be best to leave those to be found by the cleanup crew after I die.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.