Recent discussions on music box acoustics suggested benefit from
putting the music box in a corner.  I'm no acoustics expert or
physicist, but the 3-plane corner (as in the corner of a room) will
reflect incident wave energy back along its approach path.  This is
used widely in the radar reflector, I believe it works for three
mirrors and light, and it should work for sound waves.

It is a straight reflection mechanism, with no refraction used.
Of course, the three surfaces need to be at right angles to each other.
The corner reflector effect could well work in the music box scenario
by adding a near-full reflected sound to the directly transmitted
sound.

Peter Edmonds
Perth, Western Australia