Mike Knudsen asked me to explain and clarify the 26-note scale as used 
on the 26-note Trueman reed organ, which I am happy to do.

The scale was originally conceived by Ian Alderman, the English organ
builder, as an obvious way of extending the 20-note scale.  He found that
there was room for six extra notes in the margins of the standard 20-note
music roll -- 5 at one end and 1 at the other.  He used these notes to
fill in some of the gaps on the 20-note scale.

Because the resulting 26-note rolls are the same width as the standard
rolls, and the original 20 notes are still in the same position, 26-note
organs are able to play standard 20-note music, as well as the new
26-note rolls.  The 20-note rolls simply do not use the extra six notes.

This backward compatibility means that owners of the new organs already
have a rich supply of music available, in addition to the new 26-note
music.

Ian Alderman came to me for advice and collaboration on which six notes
would be the most useful to add to the existing 20-notes, and together we
devised a very satisfactory scale.  In fact, the scale is so satisfactory
that 26-note organs can play any music that the larger 31-note organs can
play -- having the same number of sharps.

As far as the allocation of the new notes goes, it is important to
establish a reference key before talking about comparisons between
scales.  As *all* organ scales can play in the key of C, I always
transpose my music to this key before converting it to another organ
scale, then transpose it up or down to suit the organ (which usually
transposes it again anyway!).

 [ The *organ* sounds as always, but Melvyn -- in effect -- uses a
 [ tracker-bar template or scale stick which is annotated as if the
 [ organ sounded in the Key of C.  This method is somewhat akin to
 [ the transposing tracker bar of some player pianos: you imagine
 [ that the music roll is in the Key of C, and you slide the moveable
 [ tracker bar until the sound is comfortable to sing with.  -- Robbie

Therefore, relative to the key of C the 20-note scale has three bass
notes (C,F,G) and one sharp, which is A#.  The extra notes added are bass
D (giving C,D,F,G); accompaniment F# ; and melody F#, C#, D# and A#.  The
compass of the organ is extended by one note, as the new A# is now the
top note.

If you study the scales of mechanical organs, you will see a common
pattern emerging as the number of keys increases.  Anybody devising a new
scale needs to understand this pattern, otherwise the scale will not make
the best use of the available keys.  It is almost essential to provide at
least one sharp, and that is A#.  Without this, only the simplest of
melodies can be played.

The next sharp to add is the F#, which I would class as "very useful but
not essential".  After this comes the C#, which is "quite handy!".  The
D# and G# are just about equal in usefulness, but on balance I would say
that the D# is slightly more useful than the G#.  As for bass notes, the
minimum number of bass notes is three: C,F and G.  Adding the D allows
most music to be arranged with hardly any missing bass notes.  After that
comes the A; then the B and E have just about equal status.

Accidentals in the bass are a luxury which most organs have to do
without!  As most music can be arranged quite satisfactorily with just
four bass notes, the scale should have a good supply of sharps on the
melody before adding a 5th bass note.

Getting back to Mike Knudsen's other query about the Deleika 26-note
scale:  This is a rather curious scale, and is not based on the 20-note
scale at all, it is totally incompatible.  Instead of using the blank
part of the 20 note roll, the spacing between the keys has been increased
which, together with the six extra notes, results in a *much* wider roll.
Only one sharp (the F#) has been added and three of the bottom accompani-
ment notes have been removed!

The resulting eight extra notes have been used to add another octave 
onto the top of the melody.  The final scale is musically similar to the
English fair organ 30 keyless book scale, which actually has 27 musical
notes.  So Mike, don't get the idea that you can put 26-note Deleika
rolls through your 20-note Deleika -- you'd need a pair of scissors and 
a hacksaw for that!

I do actually supply 26-note rolls for both the Alderman/Trueman scale,
and the Deleika scale.

As a matter of interest, does anybody know why the 20-note scale has all
that blank space on the roll in the first place?  It seems a total waste
of space and paper to make the music rolls significantly wider than they
need to be, especially for a small portable organ.  I have heard that
there was a 25-note Carl Frei scale.  Did this scale use the extra space
in the same way as does the Alderman scale?

Melvyn Wright
http://members.aol.com/supermuzik/homepage.htm

 [ Editor's Note:
 [
 [ Claus Kucher wrote (long, long ago) about the cavalier attitude at
 [ Deleika when the Austrians asked for Austrian songs.  Deleika wasn't
 [ interested.  It seems that they also deliberately made their music-
 [ roll format to be incompatible with the traditional formats which
 [ Carl Frei Sr. used and expanded upon.
 [
 [ Wolfgang Brommer and Ingmar Krause -- Could you please tell us more
 [ about the compatibility of the music rolls for the small Drehorgel?
 [ What is the standard distance between the holes in the tracker bar?
 [
 [  -- Robbie Rhodes