In reply to Arthur's query about using Cakewalk (or other similar
programs), I have done a little work on this in the past few months
in trying to convert tunes for use on an organette.  I am not familiar
with the 26-note scale Arthur mentions, bit with any such scale, you
first need to try and establish what musical key it was designed for.

You can usually tell by which sharps and/or flats are included in the
scale, or by finding our which key gives you the fullest major scale
(i.e. doh, ray, me, etc.).  Once you have established that, you need
to transpose the MIDI file up or down the musical scale to match.

In Cakewalk use Edit/Select All, to select the whole tune, then
Edit/Transpose.  At this point you get a box with +/- in.  This is
the number of semi-tones you want to transpose the music.  So if your
source has been written in C major, and your organ scale matches
E-flat, you need to transpose the music up 3 semitones.  In Cakewalk
you can't just change the key signature using the "Key+" function,
because that leaves the notes in the same place, adds a key signature,
and suitable accidentals.

Having done this bit, you need to establish whether your organ scale
covers all the notes in your tune.  Even if the original was written
for a 26-note instrument, there could be a mismatch.

The easiest way I have found of doing this in Cakewalk, is to use the
Event List View.  This is a text list of all the events and shows the
notes used, in the "Data" column.  If you compare the notes in this
column with the notes in your organ scale, you should be able to tell
if they are all covered, or where the mismatches are.

With some tunes I have found it impossible to convert them (to a 20
note scale), because some vital notes were missing, and the tune just
wouldn't sound right if you left them out.  Where the missing notes
are, effectively, accompaniment, you may be able to find suitable
alternatives if you have any knowledge of musical composition, but
we are now into the realms of "Arranging" which is a whole new can of
worms.

Although the Piano Roll view in Cakewalk is interesting, I have not
found it at all useful.  You don't seem to be able to do anything with
it.  You can't even print it.  (Unless anyone knows better).

This is just my experience over a couple of months, so I am no expert
(although I know a bit about music and can play several instruments).
Hopefully, someone with more experience can add more.

Specifically to Arthur: Since we may be nearly neighbours, if you want
to pursue this further, mail me directly on john@musicanic.com.

John Farmer
Worcestershire
UK