Ab9

Q: What notes are in the Ab9 chord?

The Ab9 chord (Ab 9th) contains: Ab, C, Eb, Gb, Bb. Its interval structure is shown above in the Theory section.

Q: How do I build Ab9 on the keyboard?

Take the root and add the remaining chord tones following the interval formula. The highlight shows chord content, while the inversion control changes which chord tone is in the bass.

Q: Which keys is Ab9 found in?

The chord acts as a diatonic degree in several keys — they are marked on the circle of fifths in the "Harmonic context" block.

Q: What can I substitute for Ab9?

A substitution depends on harmonic function and voice leading, not only on shared tones. Computed options appear in the "Substitutions" block and should be checked in context.

Ab 9th

Octaves

Musical context

ChordAb majorTriad

ChordAb9Ab 9th

ArpeggioAb majorBroken triad

ScaleAb major7 notes

KeyAb majorMajor key

ProgressionPop axisSequence

How the chord relates to the scale, mode, key and progression.

Theory

General info

Full name: Ab 9th
Symbol: Ab9
Root: Ab
Quality: 9th

Chord notes

1Abroot

3Cmajor 3rd

5Ebperfect 5th

b7Gbminor 7th

2Bbmajor 2nd

Functions & resolutions

Typical function in key: VDominant (V)C# major
Stability / tension: High tension — requires resolution
Most common resolutions: DbDb Major BbmBb Minor
Unstable degrees: 3C
4Db
resolves up to the resolution tonic
6F
b7Gb
resolves down to the tonic 3rd
Main resolution: Ab9source
DbDb Major
Dominant 7th Ab7 naturally resolves up a 4th to Db. It is the tritone between the chord's 3rd and 7th that creates this pull.
Other resolutions: Ab9source
Deceptive resolution
BbmBb Minor
Instead of the tonic, the dominant resolves to the vi degree. Creates surprise and is often used to extend a musical phrase.
Ab9source
Modal resolution
GbGb Major
In rock and blues, the dominant often moves to bVII or IV instead of the tonic, creating a modal flavor.
Ab9source
Jazz reharmonization
D7D Dominant 7
Tritone substitution: Ab7 can be replaced by D7 (a tritone away). Both chords share the same tritone between the 3rd and 7th, resolving to the same tonic.
Ab9source
Functional resolution
Absus4Ab Sus4
The dominant can resolve beyond the tonic: moving to IV (subdominant) or to a suspension (sus4) are common alternatives in pop and folk music.

Substitutions

Tritone substitution: D7D Dominant 7

Features

Character: Dominant, with a minor 7th and major 9th
Characteristic interval: 9th
Description: The major 3rd and minor 7th form a dominant core, while the major 9th adds a diatonic extension. The dominant tritone preserves directed tension toward resolution.
Application: V9–I in jazz
Funk and soul
Blues harmony

Voicing & structure

Root position

v1Ab(Ab4)Bass

root

v2C(C5)M3from Ab

v3Eb(Eb5)m3from C

v4Gb(Gb5)m3from Eb

v5Bb(Bb5)M3from Gb

Harmony

Compatible scales

All chord tones are contained in these scales — use them for improvisation.

ScaleC Locrian ScaleC Altered (super Locrian)ScaleD# Dorian ScaleD# Melodic minor ScaleD# Neapolitan major ScaleF# Lydian ScaleF# Lydian augmented ScaleG# Mixolydian ScaleG# Mixolydian ♭6 ScaleA# Aeolian (natural minor)

This chord on guitar 🎸

See how Ab9 looks on guitar.

Explore

Circle of fifths

Highlighted major keys contain this chord among their diatonic harmonies.

Relative key: FmF minor
Dominant: EbEb major
Subdominant: DbDb major
Key signature: 4 flats (Bb, Eb, Ab, Db)

What to learn next

ScaleAb MixolydianScale to improvise over this chord ChordAb Dominant 7A nearby chord on the same root — compare the sound PracticeChord trainerLock the fingering into muscle memory ProgressionChord progressionsHow this chord works inside real progressions ChordAb Major 9Another related chord to practise

Recommended for you

Ab Dominant 7A chord that sounds close

Ab Major 9A chord that sounds close

Ab Minor 9A chord that sounds close

Ab MixolydianA scale related to this chord

Ab Chromatic scaleA scale related to this chord

Practice

Keyboard Trainer

Reinforce it in practice — play and name notes on the interactive keyboard.

Open Trainer

Test yourself

(Press any key to start)

What notes are in the Ab9 chord?

How do I build Ab9 on the keyboard?

Which keys is Ab9 found in?

What can I substitute for Ab9?

Ab9