Space plays and stops
- Notes and intervals
- AbM3Cm3Ebm3Gbm3A
- Extends
- Ab Dominant 7
Ab Dominant b9, written Ab7b9, is built from Ab, C, Eb, Gb and A: the root, major 3rd, 5th, minor 7th and flat 9th.
Its 3rd and 7th, C and Gb, are its guide tones: they say what kind of chord it is, so voicings are built around them and the root is often left to the bass. D7, a tritone away, has the same two notes the other way up, so it can stand in for Ab7b9 as its tritone substitute.
In the progressions here, Ab7b9 is the V7♭9 of the Minor ii-V to Major Progression in Db.