Howard Wyman asks about the 48-note scale and building an organ to play
it. I carried out extensive research into the best scale to use for my
first fair organ and settled for the 48-note. It has a good musical
capability and a vast library of available music.
The Alan Pell 65-note scale is well worth considering. It is an
extension of the 48 to give discrete keys for the countermelody which
would just be embedded into the accompaniment notes of the 48-note
scale. In reality, the 65-note scale is really only using 64-keys as
this is a standard number for a MIDI system.
My latest organ, "Topsy", is a very compact example of a 65-note organ
and, apart from playing 65-note arrangements, it can also play music
for most of the other lesser scales. See "Topsy" on YouTube under