guitar scale
G♭ Phrygian dominant
The fifth mode of harmonic minor: a flat second over a major third, so the step from the second to the third is a step and a half.
The same sounds spelled from the other side are F♯ Phrygian dominant.
Written out
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
What is true of it
G♭ Phrygian dominant is G♭, A♭♭, B♭, C♭, D♭, E♭♭ and F♭, and back to G♭.
Its steps are H – W+H – H – W – H – W – W, where W is a whole step and H a half.
Written correctly it needs 9 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♭ Phrygian differs from it by exactly one note.
Across the first twelve frets of the guitar its notes fall in 47 places, which is what makes a scale a shape rather than a list.
Chords made only of these notes
Found by testing every chord in the catalogue against these 7 sounds, not chosen.
Other scales on G♭
C phr domC♯ phr domD♭ phr domD phr domD♯ phr domE♭ phr domE phr domF phr domall 374