[bellicon]

I want to have a 3D printing service like https://forgelabs.com/ or https://www.makelab.com/ print a pair of these horns
https://at-horns.eu/A460D.html using this STL file kit. https://cults3d.com/en/3d-model/various/ath-a460d-stl-kit

Those shops can likely print the entire horn in one pass, so printing out petals which would then have to be glued together, could be avoided.

Assuming those places will produce horns with highly accurate geometries, my other concern is choosing a resin that will have sufficient acoustic inertness-something approaching that of these lower density polyurethane boards. https://www.freemansupply.com/products/machinable-media/urethane-foam-boards

In fact, I was originally going to make the horns by CNC milling this board. https://www.freemansupply.com/produ...-styling-boards/freeman-m-3400-modeling-board But sanding the inside of the horn to eliminate any tooling marks, that could have caused HOMs or other resonance, looked to be too problematic.

And the resin must also result in the smoothest surface inside and round the mouth of the horn.

Which resins can best meet both requirements?

But what are the tradeoffs?

[FullRangeMan]

Worse material I have seen was injeted PP used in pro-audio horns.
Dry resins always have some resonance after ready.
Do you can use real wood ?