Complex and Unused Musical Keys
There are a few keynotes, namely B#, E#, and Fb, which seem to be missing from the circle of fifths. But – just like on the piano keyboard – these notes are really just C, F, and E in disguise.
Some scales are too complicated for practical use, and can be represented by a much simpler enharmonic equivalent.
Take B# major: It contains seven accidentals (five of which are double-sharps), and it’s just another way of writing the accidental-free C major scale:
- C D E F G A B
- B# C## D## E# F## G## A##
How Many Unused Scales Exist?
The circle of fifths shows only the working scales; but, since it’s really more of an infinite spiral than a circle, there’s no end to the possibilities. One could write a song in the key of B quadruple-flat if one were properly motivated (or sufficiently bored); but thankfully, it’s never necessary to make a scale this convoluted.
A key signature only needs to be as complex as seven accidentals; after that, double-sharps or double-flats come into play. Take a look at the order of the sharp key signatures (active key signatures are in bold):
(C) - G - D - A - E - B - F# - C# - G# - D# - A# - E# - B# - F## - C## (etc.)
G# major would come after the 7-sharped C# major; and it would also be the first scale to contain a double-sharp:
- G-Sharp Major: G# A# B# C# D# E# F##
(enharmonic with) - A-Flat Major: Ab Bb C Db Eb F G
Try It Yourself: The key of C-flat major is the last active scale with flats. Try to find which key would come next, and which note in its scale would have a double-flat.
The ‘Missing’ Scales
Most notes act as keynotes for both major and minor key signatures, but some only label one or the other; three keynotes aren’t seen at all – here’s a simple breakdown:
Not Seen As Major: G# A# D#
Not Seen As Minor: Cb Gb Db
Not A Working Key: Fb E# B#
To learn which keys exist, and which exist only in the minds of bored music theorists, consult the easy-to-read outline of the keynotes.
