Unfortunately, I no longer see any way to continue making my intellectual property available free of charge. After more than five years of giving so much to the community, my own benefit is not even close to zero, but far into the negative.
For this reason, I hereby revoke permission for the free use of all spreadsheet horn calculators and designs provided by me anywhere and, overall, the use of my intellectual property with immediate effect as of 23.09.2025!
For those who have already downloaded my calculators in the past (there have been thousands of downloads already!), I expect at least that you make a donation if you want to continue using them to support my work and to keep this blog alive. Otherwise, please delete all the corresponding files that are related to my intellectual property. Keeping any copies is not permitted. Please contact me by email if you would like to continue using my work to discuss conditions.
If you would like to use my calculators and designs in the future to build your own horns, please feel free to contact me by email. A license must now be purchased in order to manufacture any horn loudspeakers based on my intellectual property. In this case, please contact me by email and just shortly describe your project, and we can discuss conditions.
If you have already built any horn speakers based on my work, I would really appreciate it if you consider making a donation. Please also contact me by email in this case.
If you simply enjoy reading my blog and would like to support my work, please consider supporting me with a donation by contacting me via email to discuss the details.
Any commercial use of my intellectual property for the software, results, designs, CAD files, or documentation provided here remain strictly prohibited! But I am open for discussion about special conditions.