Discussion about DrBA horns is offloaded:
https://www.diyaudio.com/forums/multi-way/341038-drba-horns-sphericalhorns-net.html
Spread Sheet Calculators:
Kugelwellentrichter (spherical wave horn):
Version 1.09 (12.04.2021): DrBA_SWH_PETF_v109
Hyperbolic Spiral:
Version 1.02 (2019): drba_hbs_v102_qwlopt_mk1
JMLC inspired calculator:
Version 3.03 (12/2020): DrBA_JMLC_V303
14.03.2021: Removed old 32Bit code that could cause problems.
Workflow: