# Sticky  QRDude - Diffuser Calculator



## collo

QRDude is a calculator for designing QRD diffusers.

In standard mode, it provides similar functionality to existing calculators, although it adds a few features, such as support for inverse panels.

In advanced mode, it supports the design of panels that have had their wells shifted downwards, leading to savings in panel depth or lower design frequencies. Smart well width options can yield better bandwidth.

Supports metric and imperial units.

The software was developed during discussions on another forum, but since "The Shack" is a supporter of my site, it's release is being announced here.

Screenshot of advanced mode:








Available from the QRDude page


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## terry j

well done collo, you should be proud of yourself.

it IS the best qrd calculator available.


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## collo

Thanks Terry,

couldn't have done it without the help of others (mentioned on the About form..)


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## Glenn Kuras

Great job and have already spread the word!!!!!!


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## collo

Thanks Glenn - I appreciate that.


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## collo

Version 2 supports 2D QRD panels...


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## collo

Version 2.03 released to fix a bug - the text report for 2D diffusers incorrectly stated the physical well depth for normal (non-inverse) panels. 

Hopefully didn't spoil the plans of too many budding QRD builders...:whistling:
Thanks to TerryJ for spotting that one!


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## nixx

Great piece of software! Thank you 
Definitely very useful for me!


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## threadlock

Very nice tool.
Been using the mh-audio qrd calculator, but this is a lot better.
Thanks for sharing!


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## Gustavo

Hello friends:
Im new at this forum, I´ve read a lot of QRD diffusser ,
but I´ve never found information about the a recomended 
desing frequency,
Iwant to Know
whats is there any common frequency desing for multiporpose aplication.

Sorry about my english (I do sepak spanish)


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## Victor

for a home recording studio a design frequency of 800 - 900Hz should be ok.


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## collo

Although I wrote the software, I've not built a studio. I would say use whatever depth you can live with. Perhaps Bryan from GIK will chime in with a more informed answer...


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## maikol

Great to have you here Collo!

Excellent piece of software, also! :T:T:T


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## ejbragg

Collo, so glad you posted this. In fact, it was this program I used to design and build my 2D diffusers in my drum room. I'll be showing them on the "Studio Contruction" thread in the gallery, when I get caught up. I so appreciate the software. I started by doing all these calculations by hand. But I was changing things up to see what I could live with / without .... with the size & weight verses lowest frequency diffusion. Running across QRDude was quite a blessing!

Love it!


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## collo

It's great to hear of people actually using it to build some!
I'll look forward to seeing some pictures...


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## fyos

Thanks - really useful find :sn:


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## stephendbarnes

Looks like a tool I should learn to use as I will soon begin treatment of a small (13 Ft X 10Ft) mixing room.
Thanks.


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## UF6

Gustavo said:


> Hello friends:
> Im new at this forum, I´ve read a lot of QRD diffusser ,
> but I´ve never found information about the a recomended
> desing frequency,
> Iwant to Know
> whats is there any common frequency desing for multiporpose aplication.
> 
> Sorry about my english (I do sepak spanish)


I have designed my 2D Diffusors at 800 Hz, my 3Ds for 1kHz. The upper edge should be at least at 3-5 kHz. It is not so important for a diffusor to go 10 KHz. You should also create invers pannels if you planning to build array diffusors.


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## c-bass

collo, sir, you are a hero. I'm infinitely indebted to you.

I have some questions about your software. I'm trying to build QR diffusers...

For example, if I am building a diffuser of these qualifications: (1st attachment)

I see there is one grey depth unit underneath the green bars. The tallest green bar will be 11" from the backboard.

When I check the option, "Auto-optimize phase wheel rotation for shallowest 1D panel in advanced mode," I get this: (2nd attachment)

Now, there are 5 grey depth units under the green bars, and the deepest wells only have a height of 7 5/16". Despite these changes, the scatter, diffuse, and HF cutoff frequencies all have remained the same.

My questions are:

What the grey "depth units" represent, and how do they affect the diffuser? Do I have to take these into account when building the diffuser?

How is it possible that two diffusers of 11" and 7 5/16" maximum well depths can function the same? It seems to me that it would be obvious that everybody would want to build the N13+4,0, rather than the standard N13 panel, because it is far more economical in terms of space and building material.

Lastly, how does shifting the sequence to the left affect the diffuser? I want to build a N13+4,7, so that it is symmetrical, but am wondering how this will affect its function. Here is a picture of what I'm talking about: (3rd attachment)

I've read QRDude's User Guide and Technical Overview. I've tried searching all over to find this information - on and off HTS - but to no avail. I hope the answers aren't too involved. If it's any help, I could take snapshots using the metric system, instead. If I've asked too many question, I can boil them down to 2: what is the function of the depth units, and how would they affect the way I build my diffuse?

Thank you


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