Check this thread out might be insightful…
https://www.diyaudio.com/community/threads/voigt-pipe-design.403389/
Voigt Pipe speakers still a thing?
Are any of you currently using/building Voigt pipe speakers? If so I’d be interested in the drivers and materials you have used with success. I recently stumbled on to Real World Audio on YouTube and Janos there has me thinking of building a pair this year.