Matthew Caulfield asked if the disc material could make a difference
in the sound.  I answered that it might be possible for a copper or
steel disk to vibrate in sympathy with a vibrating tooth.  I have had
discussions with both Nancy Fratti and Robin Biggins.  The discussions
with them both yielded the following.

(a) The music could be enhanced by the sound being reflected outwards
from the box between the underside of the disk and the wood surface.

(b) The composition of the metal could absorb the sound more with
the zinc which is a softer metal than copper or steel.

In my opinion these two new possibilities would produce a stronger
effect than the vibrating disk could.  Any further comments would
be welcome.

Tony Ciuffini