This is a 3mf file of the linked source. I've rotated it, increased the strength, used arachne wall generator, and I'm able to print without supports. There is a brim just to increase build plate adhesion.
I printed this straight from the app with the pre-set settings. The recorder does not make any sound and the texture of the print did not come out smoothly.
The tuning is a bit suspect. The tuning is a bit suspect and It won't really play into the second octave, but could your ears stand it if it would:)? It's a toy really; not usable for serious music.