FreeCAD Acoustics

[WIP] a collection of tools to design advanced loudspeakers with Open Source Software. It will run inside FreeCAD as a workbench, thanks to its expandability.

Looking for help! This is not a project with an expected deadline, but rather a compilation of tools that will be useful in loudspeaker design. Creating a collection of Open Source software for these purposes will allow PROPER 'hobby' design, taking less time while learning more. Heck, maybe next time you go out for dinner you won't leave early because the system sounds like a goose. It is my way to contribute to the audio community of which I've learned a lot.

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TODO

Stage 0: Boilerplate

• Concept definition: create some kind of parametric waveguide script
• Implement as freeCAD workbench / easy updating / CICD -> don't require copying and pasting a macro. NOTE: modify the .ai/INSTRUCTIONS.md file with any relevant CICD changes.

Stage 1: Waveguide definition

Because being in the ballpark is not the same as being mathematically correct.

GOAL:

• Tom Danley's Paraline profile (what we started with)
  • With XY pathlength offset
• OS waveguide profile
• Equalized pathlength asymmetric waveguide (Charles Sprinkle's Image Control)
• Metacomponent to add width to the waveguide profile, add a flange etc.

Stage 2: Simulation (ATH, but FOSS)

GOAL:

• Be able to model a simple waveguide https://youtu.be/NzAnPgw_Dic?si=-HpwaKmyuil5wxTZ&t=2015

Options: NOTE: once we get into reading arxiv papers, it's probably too involved for the scope/resources I can dedicate to this.

1st: Meshing - Export mesh to external solver

• Export to Marcel Batik's ATH (not Open source, we cannot integrate :/) or ABEC.
• Approximate export to hornresp for quick measurements?

BEM, like ABEC

• FOSS BEM Meshing & export https://arxiv.org/abs/2312.00005
• http://www.openbem.dk/
• https://bempp.com/
• Does a GPU Solver exist? https://digibug.ugr.es/handle/10481/97162?show=full

FEM Acoustics simulation

• Are FR responses Possible in CalculiX? https://forum.freecad.org/viewtopic.php?t=93242
• GPU Solver exists for FEM? https://www.sciencedirect.com/science/article/abs/pii/S016926072300281X https://www.sciencedirect.com/science/article/abs/pii/S0010465523001479 https://github.com/ribesstefano/GPU-accelerated-Finite-Element-Method-using-Python-and-CUDA

Stage 3: Physical simulation

Because FreeCAD can already do FEM mechanical simulations! (see box resonance, vibration modes...) https://www.facebook.com/groups/736353126390291/posts/29469495112649376/