My Seeburg A roll nickelodeon has a xylophone hooked up to start with
the highest note on the piano keyboard, "A".  This is hole number 5
on the tracker bar, counting from the right.  The 24-bar xylophone
continues 23 notes, going down to B-flat.

I suppose this range was chosen because most nickelodeon style 'A'
rolls were arranged to have the xylophone turned on with notes playing
at the highest notes on the piano.  The xylophone bars sound most
pleasing at this range.

George Karpel
Burnaby, British Columbia, Canada