Spherical Wave Horn Generator

**This is a generator for spherical wave horns (de: Kugelwellenhorn / Kugelwellenhörner)
for getting sound sources louder by audio impedance matching.**

The small size limits it to high frequency applications.
(Except you have one of those giant printers)

It's a spontaneous minimal-effort from-scratch followup design to my old
"Tractrix Horn Generator" https://www.thingiverse.com/thing:218241
A followup that I created upon request from
madseh https://www.thingiverse.com/madseh/about

The huge overhangs here that are natural to these kind of horns
do not really allow for printing this without support (as with some tractric horns).
If I'd go for printing it then I'd probably print it with the open side facing down.
I didn't bother to cut the throat flat like with the tractric horn since
it needs to be suspended on support material anyways.

Mind matching the material-thickness to the horn-size when scaling things up.