A#m9b5

Q: What notes are in the A#m9b5 chord?

The A#m9b5 chord (A# Minor 9b5) contains: A#, C#, E, G#, B#. Its interval structure is shown above in the Theory section.

Q: How do I build A#m9b5 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#m9b5 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#m9b5?

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# Minor 9b5

Octaves

Musical context

ChordA#dimTriad

ChordA#m9b5A# Minor 9b5

ArpeggioA# minorBroken triad

ScaleA# minor7 notes

KeyA# minorMinor key

ProgressionAndalusianSequence

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

Theory

General info

Full name: A# Minor 9b5
Symbol: A#m9b5
Root: A#
Quality: Minor 9b5

Chord notes

1A#root

b3C#minor 3rd

b5Edim 5th

b7G#minor 7th

2B#major 2nd

Functions & resolutions

Typical function in key: vii°Leading tone (vii°)B major
Stability / tension: Stable — can serve as major tonic
Most common resolutions: D#D# Major FF Major GmG Minor
Unstable degrees: 4D#
b5E
resolves inward to the 4th
4D#
b7G#
resolves down to the resolution tonic
Main resolution: A#m9b5source
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#m9b5source
Deceptive resolution
GmG Minor
As the V degree, a major chord can defy expectations by moving to vi instead of I (deceptive cadence).
A#m9b5source
Modal resolution
G#G# Major
In modal context, a major chord can freely move to bVII, bIII, or bVI — characteristic of Mixolydian mode.
A#m9b5source
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#m9b5source
Functional resolution
FF Major
As the IV degree (subdominant), a major chord can resolve to V or directly to I (plagal cadence).

Features

Character: Half-diminished, with an added 9th
Characteristic interval: Diminished 5th (b5), 9th
Description: The minor 3rd, diminished 5th, and minor 7th form a half-diminished seventh chord; the major 9th adds a diatonic extension. The b5 dissonance preserves the instability of the core.
Application: ii-V in minor (extended)
Modern jazz
Substitute for m7b5 with ninth

Voicing & structure

Root position

v1A#(A#4)Bass

root

v2C#(C#5)m3from A#

v3E(E5)m3from C#

v4G#(G#5)M3from E

v5B#(B#6)M3from G#

Harmony

Compatible scales

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

ScaleC Enigmatic scale ScaleC Phrygian dominant ScaleC Altered (super Locrian)ScaleC# Melodic minor ScaleC# Neapolitan major ScaleE Lydian augmented ScaleG# Mixolydian ♭6 ScaleG# Harmonic major ScaleA# Romanian minor ScaleA# Ukrainian Dorian

This chord on guitar 🎸

See how A#m9b5 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#m9b5 chord?

How do I build A#m9b5 on the keyboard?

Which keys is A#m9b5 found in?

What can I substitute for A#m9b5?