We'll be looking at the 7th (flat 9) chords which are also diminished chords.

There is only one note difference between a Dmin7(b5) and G7(b9) chord. The C in the Dmin7(b5)is a B in the G7(b9).

Here are the Drop-2 voicings:

A scale that sounds great on Dominant (flat 9) chords is the harmonic minor. The Harmonic minor is like a major scale but it has a flat 3rd and a flat6 (13th). For G7(b9) we can use the C Harmonic minor.



Finally, here is the G7(b9) arpeggio around the third fret.