QRDude
Use this free software to design your QRD diffuser
QRDude saves you having to get out the calculator to work out the well depth for your diffuser.
It will design standard and advanced 1D panels, plus standard 2D panels, in normal and inverse variations.
Features of current version - V4.50
- Supports 1D and 2D QRD panels based on prime numbers 3 through to 101
- Calculates 1D regular and Inverse panels in standard or depth-optimised variants
- Calculates 2D regular and Inverse panels in standard variants. Please Note June 2026 - 2D depth-optimised panel no longer supported. See the 2D User Guide for more details
- Auto-calculates well widths based on period width and build depth. May be over-ridden to fine-tune panel width or HF cutoff frequency
- Work in mm, decimal inches or fractional inches to 1/16th inch
- Option to lock build depth and allow design frequency to change as different panels are explored
- Displays period width and build depth (deepest well)
- Displays LF cutoff frequency one octave below lowest diffusion frequency, and displays HF cutoff frequency, where well width equates to half-wavelength
- Advises minimum seating distance based on three times the wavelength of lowest diffusion frequency
- Can display wells as Ratios, Depths, Block heights, or Phase shifts
- Phase wheel shows the phase shifts introduced by the wells at the design frequency
- Visualisation of scattering based on relative well depth either side of fin
- Scorecard screen checks for common problems and lists effective diffusion frequencies
- Supports shifting panel one half well left for symmetrical build when first well is zero-depth
- Advanced mode to find new 1D panels by rotation of phase wheel. Full horizontal shift facility
- Build depth optimiser
- Usable ranges explorer to see changes to bandwidth due to signal angle
- Lobes screen to see diffusion pattern for multiple 1D panels
- Export 1D results and scorecard to text file report
- Export 2D cut list and weight estimate to text file report
- Copy pictures to clipboard
- Resizable Visualiser screen shows realistic front view, up to 3 panels wide
Note regarding download of new versions
Microsoft Defender seems to have toughened up it's scrutiny of new downloaded software that it hasn't checked out yet.
Downloading results in a warning message from Defender stating that "This software isn't downloaded often".
This message is a standard security warning triggered by browsers (like Microsoft Edge or Google Chrome) and Windows Defender SmartScreen.
It simply means the file is new or isn't downloaded frequently enough to establish a reputation, not necessarily that it is malicious.
You can manually authorize the download through a few simple clicks:
In Microsoft Edge: Click the three dots beside the file name, select Keep, and then click Keep anyway when the final warning appears
In Google Chrome: Click the up-arrow or the menu next to the file at the bottom of the screen and click Keep.
Note regarding Running new versions
After Downloading: When you try to run QRDude, Windows may block it again. This means that Microsoft Defender does not yet recognise the latest version of QRDude.
A request has been sent to Microsoft for Version 4.50 to be scanned and added to the approved list (20th June 2026). This normally takes a week or so.
It you are happy to procede, Click More info on the blue SmartScreen window, then select Run anyway.
If you prefer to wait for Microsoft, you can Download Version 4.02 which has been up for quite some time and should not get the last warning.
Filesize 565,248 bytes
MD5 Hash Code 585B770BCF352C86DECC66D3119EE74C
The differences between V4.50 and V4.02 are minor:
- Support removed for Depth Optimised Inverse 2D Diffusersr
Once the approval is through, this notice will be hidden until I have to do it all again with the next upgrade.
Version 4.50QRDude is written in Visual Basic 6 and runs under Windows. It requires a screen width of 1024 pixels or higher
To run this software on an Apple Mac or possibly on Linux, you will need to install the Wine windows compatibility layer
Security information:
Filesize 532,480 bytes
MD5 Hash Code 048E2B4B6B3BADB8AC7521B3992595EF
Hash Code Generator to verify software against this value can be downloaded here
If you find the QRDude software and its supporting documentation useful, please consider buying me a coffee..
Supporting documentation
An illustrated overview of QRD diffusers can be found on the QRD Technical Overview page - it strongly recommended that you read this first.
For detailed instructions on how to use the calculator, see the QRDude User Guide
To see how mine went together, see the Build page
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