Hello, I am looking to make some music boxes for Christmas this year,
using 18-note movements. Can anyone please tell me the recommended
thickness of a soundboard?

What sort of timber is best for this? Would shellac-coated 6mm MDF
[medium density fiberboard] be suitable? These boxes will be heirloom
pieces with the box and lid being made of local silky oak timber.

Finally, is there an optimum design for the box that gives nice loud
amplification? I appreciate all ideas and suggestions.

Warm regards to all,
Joe Slaven

 [ You should examine the construction of the flat, wooden sounding
 [ board that lies beneath the strings of an ukulele or guitar. The
 [ wood, traditionally of spruce or similar, transmits the vibration
 [ from the strings to the air with minimal loss of sound energy.
 [ Tap your fingernail gently on the spruce surface and then compare
 [ the sound with tapping on MDF. -- Robbie