• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Free Bandpass Box Optimization Tool (4th / 6th / 8th Order) – Looking for Feedback

C

Chlobao

New Member
Hi everyone,

I’d like to share a free bandpass enclosure optimization tool I’ve been developing and invite the DIY community here to test it and give feedback.

This is my first program written in Python, and I’m still learning the language, so bugs and quirks will probably occur — your feedback will be extremely valuable!

The software focuses on bandpass loudspeaker design and currently supports:
  • 4th-order bandpass
  • 6th-order parallel-tuned bandpass
  • 8th-order parallel-tuned bandpass
The goal is not just simulation, but automatic optimization of:
  • Chamber volumes
  • Vent lengths
All results are calculated from Thiele–Small parameters, using a 2nd-order vent model to account for vent capacitance and estimate the first vent resonance. Results are displayed graphically during the optimization process.

Important: A PDF manual is included with the program. It is strongly recommended to read it, especially if you’ve never used Particle Swarm Optimization (PSO) or similar optimization methods before. The manual explains the basic workflow and how to get meaningful results safely.

Main features
  • Automatic optimization (no manual trial-and-error)
  • Real-time progress and result updates
  • SPL, cone displacement, vent velocity, and impedance plots
  • Support for 4th, 6th, and 8th-order bandpass enclosures
  • Designed for DIY experimentation and learning
Why I’m posting here
This project was built primarily for DIY audio enthusiasts, and I’d really like feedback from people who:
  • Design bandpass boxes regularly
  • Enjoy experimenting with different alignments
  • Want to stress-test the optimizer with real drivers
I’m especially interested in:
  • Usability feedback
  • Validation of results
  • Feature suggestions
  • Bug reports
Availability
The program is currently available as a Windows executable.

1767580510023.png



If there is interest, I can also consider:
  • Additional bandpass orders (5th, 7th, etc.)
  • Export options
I’m not selling anything — this is a community-driven tool, still evolving, and part of my Python learning journey.

Thanks in advance to anyone willing to try it and share thoughts. I’m happy to discuss the math, assumptions, or implementation details if anyone is interested.

Link to download (V1.4): https://www.dropbox.com/scl/fi/r1vp...ey=grx4zxhvhfib5whb75csnu3o2&st=jvo68gmt&dl=0

Best regards,

Marcos J. Jacoboski
 
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V1.10 Available: Dropbox
  • Bug fixed: The vent velocity plot in the 4th-order BP enclosure was using the Sv1 value instead of Sv2 for scaling.
  • Bug fixed: If the first solution set was the global best, the plot function was never called.
  • Improved objective function, using higher gain across the passband.
I hope to implement a function to open an excel file with the subwoofer parameters in the next version.
Enjoy!
 
Good day!
V1.11 of the optimizer is available with a bunch of new stuff:
  • Simplified units: You can now work with liters, centimeters, and millimeters instead of cubic meters and meters. Apparently, not everyone enjoys working with SI base units!
  • Speaker parameter import: There's now a button to load subwoofer parameters from an Excel file. You can save the parameters of all your drivers in a spreadsheet and load them whenever you need them. An Excel template is included in the download.
  • A logo! Yes, the optimizer finally has its own logo. It was harder than it sounds, believe me!


    link: Dropbox

    Hope you enjoy it!
 
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