Ab9b5

Q: What notes are in the Ab9b5 chord?

The Ab9b5 chord (Ab 9b5) contains: Ab, C, D, Gb, Bb. Its interval structure is shown above in the Theory section.

Q: How do I build Ab9b5 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 Ab9b5 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 Ab9b5?

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 9b5

Octaves

Musical context

ChordAb majorTriad

ChordAb9b5Ab 9b5

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 9b5
Symbol: Ab9b5
Root: Ab
Quality: 9b5

Chord notes

1Abroot

3Cmajor 3rd

b5Ddim 5th

b7Gbminor 7th

2Bbmajor 2nd

Functions & resolutions

Stability / tension: High tension — requires resolution
Most common resolutions: DbDb Major BbmBb Minor
Unstable degrees: 3C
4Db
resolves up to the resolution tonic
4Db
b5D
resolves inward to the resolution tonic
6F
b7Gb
resolves down to the tonic 3rd
Main resolution: Ab9b5source
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: Ab9b5source
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.
Ab9b5source
Modal resolution
GbGb Major
In rock and blues, the dominant often moves to bVII or IV instead of the tonic, creating a modal flavor.
Ab9b5source
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.
Ab9b5source
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 9th and diminished 5th
Characteristic interval: Diminished 5th (b5), 9th
Description: The minor 7th establishes the dominant structure, the 9th extends it, and the diminished 5th adds a second tritone against the root. The chord is more dissonant than a regular 9.
Application: Tritone sub with ninth
Jazz and fusion
Improvising over Lydian dominant

Voicing & structure

Root position

v1Ab(Ab4)Bass

root

v2C(C5)M3from Ab

v3D(D5)M2from C

v4Gb(Gb5)M3from D

v5Bb(Bb5)M3from Gb

Harmony

Compatible scales

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

ScaleC Whole tone scale ScaleD Whole tone scale ScaleF# Whole tone scale ScaleG# Whole tone scale ScaleA# Whole tone scale ScaleE Whole tone scale ScaleD Enigmatic scale ScaleD Altered (super Locrian)ScaleF# Lydian augmented ScaleA# Mixolydian ♭6

This chord on guitar 🎸

See how Ab9b5 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 Chromatic scaleScale to improvise over this chord PracticeChord trainerLock the fingering into muscle memory ProgressionChord progressionsHow this chord works inside real progressions

Recommended for you

Ab Chromatic scaleA scale related to this chord

Practice

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What notes are in the Ab9b5 chord?

How do I build Ab9b5 on the keyboard?

Which keys is Ab9b5 found in?

What can I substitute for Ab9b5?