I wanted to try printing the shape of the cavity and then casting each half in concrete so I didn't have to use a ton of filament. The shape is the "negative" of the stl.

If you sink the model 8mm into the plate, you can cut a piece of the horn off and not need and support or raft/etc. Then if you rotate the model 180 degrees and sink it 52mm below the plate, you get the remaining piece of the horn that you can glue back on. The included screenshot shows you what it looks like in cura if you do this.

Of course, you will need to take this model and make a mirror image/do the same thing for the other side of the cavity.

I haven't attempted this yet, but I'm planning on printing at .3mm height, 0% infill, 0 top layers, everything else normal.