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Fig. 1 · Gb double harmonic · first 12 frets

ukulele scale

G♭ double harmonic

G♭1A♭♭♭2B♭3C♭4D♭5E♭♭♭6F7

Two augmented seconds in one scale, one above the tonic and one below the octave.

The same sounds spelled from the other side are F♯ double harmonic.

on guitaron piano

Written out

Fig. 2 · Gb double harmonic, ascending

Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.

The step pattern

G♭HA♭♭W+HB♭HC♭WD♭HE♭♭W+HFHG♭

What is true of it

G♭ double harmonic is G♭, A♭♭, B♭, C♭, D♭, E♭♭ and F, and back to G♭.

Its steps are H – W+H – H – W – H – W+H – H, where W is a whole step and H a half.

Written correctly it needs 8 alterations, A♭♭ and E♭♭ among them. That is what the letters force, and it is also why nobody writes music in this key: the same notes spelled from the other side are easier to read.

On the same tonic, G♭ harmonic major differs from it by exactly one note.

Across the first twelve frets of the ukulele its notes fall in 29 places, which is what makes a scale a shape rather than a list.

Chords made only of these notes

G♭majorG♭augaugmentedG♭maj7major seventhB♭majorB♭mminorB♭augaugmented

Found by testing every chord in the catalogue against these 7 sounds, not chosen.

Other scales on G♭

G♭ Phrygian dominantexoticG♭ Lydian dominantexoticG♭ alteredexoticG♭ majormajorG♭ natural minorminorG♭ harmonic minorminor

C dbl harmC♯ dbl harmD♭ dbl harmD dbl harmD♯ dbl harmE♭ dbl harmE dbl harmF dbl harmall 374