Ab7♭5#9 — Ab dominant seventh flat fifth sharp ninth chord

A dominant seventh chord with both the fifth and the ninth altered: the flat fifth and the sharp ninth are the two notes that make the chord fully altered.

1 = Ab
3 = C
b5 = Ebb
b7 = Gb
#9 = B

Symbol: Ab7♭5#9
Root: Ab
Quality: Dominant seventh flat fifth sharp ninth
Family: altered
Notes: Ab C Ebb Gb B
Degree formula: 1 3 b5 b7 #9
Semitones from the root: 0 3 4 6 10
Distinct pitch classes: 5
Interval structure: Stacked from the root: 4 semitones, 2 semitones, 4 semitones, 5 semitones
Notation: Written 7♭5#9 or 7♭5(#9). A whole-tone dominant, resolving a fifth down.
Key: Ab · Ab major / F minor key signature

Formula

The chord tones in order from the root, with the interval each one forms above it.

Degree	Note	Semitones	Interval from the root
1	Ab	0	Perfect unison
3	C	4	Major third
b5	Ebb	6	Tritone
b7	Gb	10	Minor seventh
#9	B	3	Minor third

Degree

Note

Semitones

Interval from the root

Perfect unison

Major third

Ebb

Tritone

Minor seventh

Minor third

Inversions

An inversion is the same set of notes with a different one in the bass. The last column gives the distance of each note above the bass note, in semitones.

Inversion	Bass note	Degree in the bass	Notes above the bass	Semitones above the bass
root position	Ab	1	Ab – C – Ebb – Gb – B	0 4 6 10 3
first inversion	C	3	C – Ebb – Gb – B – Ab	0 2 6 11 8
second inversion	Ebb	b5	Ebb – Gb – B – Ab – C	0 4 9 6 10
third inversion	Gb	b7	Gb – B – Ab – C – Ebb	0 5 2 6 8
fourth inversion	B	#9	B – Ab – C – Ebb – Gb	0 9 1 3 7

Inversion

Bass note

Degree in the bass

Notes above the bass

Semitones above the bass

root position

Ab – C – Ebb – Gb – B

0 4 6 10 3

first inversion

C – Ebb – Gb – B – Ab

0 2 6 11 8

second inversion

Ebb

Ebb – Gb – B – Ab – C

0 4 9 6 10

third inversion

Gb – B – Ab – C – Ebb

0 5 2 6 8

fourth inversion

B – Ab – C – Ebb – Gb

0 9 1 3 7

Playable voicings

These shapes were found by searching the fretboard of a standard-tuned guitar (E A D G B E) rather than copied from a chord book. The search allows every string to sound or to be muted, rejects any shape with a muted string between two sounding strings, rejects any shape whose fretted notes span more than four frets (a five-fret window), requires every chord tone to be present, and then sorts what remains with root-position shapes first and the most compact, lowest shapes next. The shapes shown are the first six of that ordering; other orderings are possible at the same frets.

#	Shape (low string first)	Notes	Degrees	Bass	Span (frets)	Sounding strings
1	4-3-4-4-3-4 (6→1)	Ab C Gb B D Ab	1 3 b7 #9 b5 1	Ab	1	6
2	4-3-4-4-3-2 (6→1)	Ab C Gb B D Gb	1 3 b7 #9 b5 b7	Ab	2	6
3	4-2-4-5-3-2 (6→1)	Ab B Gb C D Gb	1 #9 b7 3 b5 b7	Ab	3	6
4	4-2-4-5-3-4 (6→1)	Ab B Gb C D Ab	1 #9 b7 3 b5 1	Ab	3	6
5	4-5-4-5-7-7 (6→1)	Ab D Gb C Gb B	1 b5 b7 3 b7 #9	Ab	3	6
6	4-5-6-5-7-7 (6→1)	Ab D Ab C Gb B	1 b5 1 3 b7 #9	Ab	3	6

Shape numbers run from the lowest string to the highest, so the left-hand number is the sixth string (low E) in standard tuning. Multiple shapes are listed because a chord can be voiced several ways, and because a lower position is not always the better sounding one.

Related chords and scales

KeyEverything in Abscale, chords and neck map for this root
ScaleAb whole tonethe scale this chord comes from
ChordAb7♭9the dominant seventh flat ninth it extends
ChordAbthe triad underneath it
ChordAb7the seventh chord on this root

Everything in Ab · All chords

KeyKey of AbAb Bb C Db Eb F G · Ab major / F minor
ScaleAb whole tone6 notes · 1 2 3 #4 #5 b7
ChordAb7♭9 — Dominant seventh flat ninth1 3 5 b7 b9 · Ab C Eb Gb Bbb
ChordAb — Major1 3 5 · Ab C Eb
ChordAb7 — Dominant seventh1 3 5 b7 · Ab C Eb Gb
ChordAb7b5 — Dominant seventh flat five1 3 b5 b7 · Ab C Ebb Gb
ChordAb7#11 — Dominant seventh sharp eleventh1 3 5 b7 #11 · Ab C Eb Gb D
ChordAb7#5 — Dominant seventh sharp fifth1 3 #5 b7 · Ab C E Gb

Everything in this key: Ab · Chords · Theory Atlas