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I am glad that Bill Finch raised recently the subject that I call
"MIDI standardization for band organs" [060417 MMDigest].  I believe
that this issue is an important point for all those willing to design
and build or buy a band organ or a more wide chromatic instrument
taking advantage of the MIDI technology.

Besides the precious availability of MIDI transpositions of vintage
rollbooks, which contributes to the preservation of the history, the
large availability of MIDI files of every kind of music represents a
challenge for people willing to convoy all those streams of data inside
a mechanical music machine and listen to the sound effects and enjoy
them.  However, this cannot be obtained unless you design carefully
your mechanical tone generator to interface properly the MIDI data
stream and, on the other side you have to properly organize the
architecture of the MIDI tracks of the tune, spending a lot of time
for the re-orchestration of the file.

Generally the commercial MIDI files contain a number of instrumental
parts each one placed in a different MIDI channel (1-16) and in each
channel there is space for a scale of 128 notes.  Conventionally the
Channel 10 is utilized for percussion instruments while all the others
are employed for the various instruments.

There are no conventions on where to allocate different instrumental
parts in the various channels and besides this role, a channel can be
utilized also for auxiliary functions (for example chords to drive
harmonizers, etc.)  In this situation, if you wish to utilize a
commercial MIDI file to drive your band organ, you must first go
through an analytic and restructuring process of the MIDI file which
consists of a few phases.  This can easily be done with a PC running
a sequencer program.

First of all, once the MIDI file has been loaded, you have to analyze
how the MIDI tune is organized: how many instrumental parts and in
which channels they are located. At that point you may choose the
tracks suitable for your instrument and copy/paste them in a new file.
Then you have to check the note extension of the channels of your
interest to verify if your mechanical instrument can generate all
of them or some notes are forbidden.

Clearly a new fully chromatic mechanical instrument is advantaged
because more likely it will play all or most of the notes of the MIDI
file tunes.  Eventual modifications can be done with the editing
functions of the sequencer, which also allows the transposition to
any key.

But let's come back to the main issue: is it there a kind of MIDI
standardization for band organs or organs in general?  To my knowledge,
for the time being the answer is "No"; there are proprietary solutions
only, which do not allow MIDI files interchange.

The reason is very simple: when the MIDI protocol was established,
all the major worldwide manufacturers of electronic instruments of that
time sat down at the same table and defined a specification which was
universally accepted.  Still today all the new instruments comply
strictly to this spec.

In view of this, among several other features, when you address
a program change 1 you get a piano sound, while with a 74 you get
a flute and with a 25 you get an acoustic guitar whichever is the
electronic tone generator utilized.  By doing this on different
channels of a MIDI file, you may obtain for example a string quartet or
a combo jazz or a big band or whichever combination of instruments you
like.  This works because all the manufacturers of MIDI tone generators
have accepted the standard.

Unfortunately the mechanical musical instrument manufacturers were not
sitting at that table around the year 1982.

MIDI, however, has proven to be a very solid and flexible tool, still
well alive notwithstanding its 8-bit technology.  (I loved writing MIDI
programs in assembler with the Commodore 64 at that time, including
a MIDI to CV interface for the Moog Satellite).

It offers potentially, as is, the possibility to define a standard for
MIDI files and interfaces dedicated to band organs and the like, if
only the major contemporary manufacturers and/or music arrangers and/or
MIDI decoder board manufacturers and/or the most active amateur organ
builders would like to organize a table where to discuss proposals and
agree a range of common solutions.

For the architectural aspect I share the vision expressed by Mike
Knudsen in his answer to Bill Finch.  This would be beneficial for
the whole sector and in particular for those willing to interchange
music files and to buy standard files ready to play.

To further dig into the matter, today you can find on the market a few
proposals for MIDI to magnet decoders quite affordable, that can be
utilized to decode, for example, up to 64 notes of a MIDI channel of
your choice by means of preset switches.  As indicated by Mike, the
simplest way to address different ranks of pipes is to assign each of
them to a single MIDI decoder, each one tuned to a different MIDI
channel.  Besides the multiplication of costs, this solution seems
suitable where your ranks consist of a considerable number of pipes.

JW Electronics has introduced a clever feature in its 64 note decoder
which allows to assign easily different magnet outputs to notes of
different MIDI channels.  Notwithstanding the relatively small number,
you can do a lot of things with 64 different magnets and this seems to
be a good starting point to try a standardization which would allow to
align three elements: the organ pipe ranks and percussions, the MIDI
decoders and the MIDI files for band Organs and the like.

The MIDI endorsement of all the electronic industry so far keeps
maintaining alive a universally accepted platform which probably could
be adopted in a shared common way also by the mechanical instruments
manufacturers and users community.

Manufacturers out there, what do you think?

Kind regards to all organ grinders ("suonatore d'organo a manovella"
in Italian language ;)

Aldo Laus
Milano, Italy
http://www.musicaldo.com/