[ Bill Finch wrote in 060417 MMDigest:

> I am curious to know if anyone has worked out a standard MIDI protocol
> channel and key assignments) for band organs? Would it seem logical
> to assign each pipe rank to a separate MIDI channel and just use
> a MIDI note number that corresponds to the pitch of each associated
> pipe within the rank? Would this be the simplest design spec for a
> newly constructed organ?

For a new organ that is not required to be compatible with any existing
rolls, it would indeed be most effective to give each rank its own MIDI
decoder board, each rank on a different MIDI channel, and play each
pipe independently.  This would give the "roll" arranger tremendous
flexibility, in that any rank can be used as solo, accompaniment,
melody, countermelody, bass helper, whatever.  No rank would have any
fixed allegiance to any organ division, much as in a theater organ.

Melody notes could be accented by adding other "stops" just for that
note.  But the whole notion of "stop" would become just a software
convention of MIDI "layering", that you can override at will.  Duplexing
and unification at the individual note level.  I'd like to see the
music editing software interface for this (and would like to work on
it).

Ranks could also be played at various pitches -- an 8' rank could be
played at 4', if you avoid the top octave, etc.

Existing MIDI files in conventional stop/division form could be
translated into this free-wheeling format, given the desired
registrations.

The windchest would be just a big flat box full of electric valves,
very simple to build and maintain -- but all those solenoid coils might
weigh more than the leather pouches and extra wood of a conventional
slider, pitman, or ventil chest system.  Probably not, though.

There is a question: given a 4' rank of piccolos, would you MIDI number
them at actual pitches (adding 12 to each pipe number, relative to an
8' pipe), or would you number them the same as an 8' rank, so the same
MIDI note number would automatically play an octave higher?  I suspect
different builders would make different choices.

I have intentions to build such an organ in my basement, and haven't
yet resolved that pitch numbering issue -- nor the human arranger's
interface!

> If any of you have MIDIfied a new or existing band organ, what protocol
> did you use and how did you arrive at it?

Well, I only MIDIfied a 31-note Raffin cart crank organ, where none of
the three divisions' notes overlap, but are continuous up the scale.
So it was a trivial decision to put them all on one channel, at their
true pitches.

I'd say that if you MIDIfied an existing band organ, you'd have one
valve per roll frame hole, meaning you'd respect the existing divisions
and stops as found, since the chest won't let you control individual
pipes.  You could use separate channels per division, or just space
them out (maybe at octave offsets) across the 128-note MIDI "tracker
bar."  The MIDI-controlled roll puncher for "Trudy" is laid out in the
latter fashion, logically equivalent to playing that organ directly
from MIDI.

Stop control of a conventional organ is a whole 'nother matter.

Mike Knudsen