> I am a composer and would like to write some new music
> for a musical box.  One thing I need to know to do this is
> which music boxes are chromatic ...

Hello Troy,  Yours sounds like an interesting project, but finding
a truly chromatic musical box will be difficult.  Most boxes favour
one key, sometimes venturing a little further by modulating into
harmonically close keys for a little variation.

As for most mechanical instruments, the object of the design is to use
all notes as efficiently as possible so that space isn't taken up by
seldom-to-never used notes.  Staying in one key can eliminate a lot of
inefficiencies.

Some disc boxes are chromatic but this is not the usual case.  I checked
Graham Webb's Disc Musical Box Handbook, which has a few tuning scales
in it for Polyphon and Symphonion and, although close, the 15-1/2"
Polyphon (I am assuming the same scale for the Regina) does not contain
a fully chromatic octave.  You might be better off checking out a
similar-sized Symphonion which may have an octave or so that is
chromatic.

A very important point to remember is that if the object of your
endeavour is to play your finished product with other instruments,
you will have severe tuning problems as musical box partials do not
follow a true harmonic progression and vary quite widely at the ends
of the scale.  (Octaves are highly stretched and equal temperament
is usually not a reality.)

All that said, I am left wondering if you intend to have your music
transcribed onto musical box discs or cylinders?  That is quite another
story from both the mechanical technical sides as well as the arranging,
which is highly specialized.

I could make suggestion that could save a whole bunch of work although
it is cheap and nasty, and that is to ask if you have considered using
a music synthesizer set up to sound like a musical box?  The keyboard
would be a snap.  Also, deep in my memory I seem to recall that a number
of years ago one of the subscribers of MMD actually made available to
us a program that played MIDI files as though they were being performed
by a disc musical box.  It is quite effective.

Now I'm rambling.  Hope this helps.

Best regards,
Jim Heyworth
Sechelt, B.C., Canada