A#b13#9

Q: What notes are in the A#b13#9 chord?

The A#b13#9 chord (A# b13#9) contains: A#, D, E#, G#, C#, F#. Its interval structure is shown above in the Theory section.

Q: How do I build A#b13#9 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 A#b13#9 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 A#b13#9?

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.

A# b13#9

Octaves

Musical context

ChordA# majorTriad

ChordA#b13#9A# b13#9

ArpeggioA# majorBroken triad

ScaleA# major7 notes

KeyA# majorMajor key

ProgressionPop axisSequence

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

Theory

General info

Full name: A# b13#9
Symbol: A#b13#9
Root: A#
Quality: b13#9

Chord notes

1A#root

3Dmajor 3rd

5E#perfect 5th

b7G#minor 7th

#2C#aug 2nd

b6F#minor 6th

Functions & resolutions

Stability / tension: Stable — can serve as major tonic
Most common resolutions: D#D# Major FF Major GmG Minor
Unstable degrees: 4D#
b7G#
resolves down to the resolution tonic
Main resolution: A#b13#9source
FF Major
Major chord A# is a stable tonic. As tonic it doesn't require resolution, but in a progression context typically moves to IV or V.
Other resolutions: A#b13#9source
Deceptive resolution
GmG Minor
As the V degree, a major chord can defy expectations by moving to vi instead of I (deceptive cadence).
A#b13#9source
Modal resolution
G#G# Major
In modal context, a major chord can freely move to bVII, bIII, or bVI — characteristic of Mixolydian mode.
A#b13#9source
Jazz reharmonization
A#maj7A# Major 7
In jazz, a major chord is enriched to maj7, 6/9, or add9 and can smoothly transition into a ii-V of another key (modulation).
A#b13#9source
Functional resolution
FF Major
As the IV degree (subdominant), a major chord can resolve to V or directly to I (plagal cadence).

Substitutions

Tritone substitution: E7E Dominant 7

Features

Character: Dominant, with #9 and b13
Characteristic interval: Augmented 9th (#9), Minor 13th (b13)
Description: The augmented 9th clashes chromatically with the major 3rd, while the minor 13th lies a semitone above the perfect 5th. The two alterations intensify dominant dissonance.
Application: Avant-garde jazz
Altered dominants
Experimental harmony

Voicing & structure

Root position

v1A#(A#4)Bass

root

v2D(D5)M3from A#

v3E#(E#5)m3from D

v4G#(G#5)m3from E#

v5C#(C#6)P4from G#

v6F#(F#6)P4from C#

Harmony

Compatible scales

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

ScaleF# Harmonic major ScaleF# Bebop major ScaleC# Chromatic scale ScaleD Chromatic scale ScaleF Chromatic scale ScaleF# Chromatic scale ScaleG# Chromatic scale ScaleA# Chromatic scale ScaleC Chromatic scale ScaleD# Chromatic scale

This chord on guitar 🎸

See how A#b13#9 looks on guitar.

Explore

Circle of fifths

Highlighted major keys contain this chord among their diatonic harmonies.

Relative key: GmG minor
Dominant: FF major
Subdominant: EbEb major
Key signature: 2 flats (Bb, Eb)

What to learn next

ScaleBb 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

Bb Chromatic scaleA scale related to this chord

Practice

Keyboard Trainer

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

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Test yourself

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What notes are in the A#b13#9 chord?

How do I build A#b13#9 on the keyboard?

Which keys is A#b13#9 found in?

What can I substitute for A#b13#9?