Ab Dominant Flat 9th
Ab7b9
Notes
Ab · C · Eb · Gb · Bbb
Intervals
- RootAb (1P)
- Major 3rdC (3M)
- Perfect 5thEb (5P)
- Minor 7thGb (7m)
- Minor 9thBbb (9m)
Fretboard
On the fretboard, Bb represents Bbb.
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About
The A♭7♭9 (A♭–C–E♭–G♭–B♭♭) alters the dominant 9 by lowering the ninth a half step. The B♭♭ creates a half-step clash with the root, amplifying the chord’s dissonance and intensifying its pull toward resolution. Because the interval between root and ♭9 is a minor ninth — one of the sharpest dissonances in tonal harmony — 7♭9 chords generate significantly more tension than standard dominants. They are especially idiomatic as V chords resolving to minor tonics; here A♭7♭9 → D♭m, where the ♭9 relates diatonically to the target minor key. The 3rd and ♭7 remain the essential harmonic tones; the ♭9 is the defining alteration. The 5th can be omitted.
Similar chords
Chords sharing two or more notes with this one, ranked by overlap.
Scales containing this chord
- B♭ Natural Minor (VII)
- D♭ Diminished (deg 5)
- D♭ Harmonic Minor (V)
- D♭ Major (V)
- D♭ Melodic Minor (V)
- E♭ Diminished (deg 4)
- E♭ Melodic Minor (IV)
- A♭ Mixolydian (I)
- C Locrian (VI)
- E♭ Dorian (IV)
- F Phrygian (III)
- F♯ Lydian (II)
Scales whose notes include every chord tone. Roman numeral marks the chord root’s position in the scale; dashed badges aren’t linked yet.