The original design is very good, so I made the shape of the horn based on it.
Therefore, when printing, it is recommended to lay it on its side and set some support material.
I think PLA or PETG are good materials.
-UPDATE-
Since the addition of the horn made it difficult to insert the cable, a portion of the receiver was cut open.
It is easy to handle when used with an L-shaped adapter.
The author remixed this model.
The sound is steered forward by the horn, making it very audible.