Lesson 38 - Enharmonic modulation using fully diminished seventh chords
Part I - The fully diminished seventh chord's symmetry
Ready to have your mind blown?
There are only THREE fully diminished seventh chords, and using them, one can modulate from any key, to any key.
No matter what inversion the chord is in, it is always three minor thirds stacked on top of each other.
Here's an example of the symmetry of a fully diminished seventh chord on B flat:
The only three fully diminished seventh chord in existence are:
1. Those that contain C (or its enharmonic equivalent)
2. Those that contain C# (or its enharmonic equivalent)
3. Those that contain D (or its enharmonic equivalent)
Go ahead, try it! with those spellings, one can create all fully diminished seventh chords on every note. And since no matter what inversion the chord is in, it is always made up of minor thirds, one can create every fully diminished seventh chord on every pitch center!
Part II - Enharmonic modulation with the fully diminished 7th Chord
With the symmetrical properties of the fully diminished seventh chord, that chord can be resolved to a different pitch that would be indicated by the spelling.
Here is an example of respelling a single note in order to resolve to a chord that would not be immediately apparent.
Listen:
Here's the same example, but it modulates to G Major instead of A Major:
G#BDAF
BDFAb
Listen:
In this example, the fully diminished seventh Chord has three possible spellings:
ACEbGb--given spelling
D#F#AC
F#ACEb--Preferred spelling
Listen:
