A 9♭5
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A9♭5
A – C♯ – E♭ – G – B
Formula:R-M3-d5-m7-M9
Intervals:P1-M3-d5-m7-M9
Scale Degrees:1-3-b5-b7-9
Introduction

The A 9♭5 chord is a five-note chord made up of A, C♯, E♭, G, and B. It is built from a root, major third, diminished fifth, minor seventh, and major ninth.
Notes
Key Signature
The key of A 9♭5 has 3 sharps.
F♯C♯G♯
Order of sharps
Sharps are added to a key signature in a fixed order. Each new sharp key adds the next sharp on the list.
F♯C♯G♯D♯A♯E♯B♯
Mnemonic: Father Charles Goes Down And Ends Battle
Chords in the Key of A Major
These are the diatonic triads built on each degree of the A major scale:
C
D
E
F
G
A
B
C
D
E
F
G
A
B
I — A Major (major)
Theory: Intervals
Formula: R-M3-d5-m7-M9
Intervals: P1-M3-d5-m7-M9
The A 9♭5 is built by stacking intervals from the root note. The formula R-M3-d5-m7-M9 describes the scale degrees used. The intervals P1-M3-d5-m7-M9 show the distance between each note in the chord.
A 9♭5 — Frequently Asked Questions
What notes are in the A 9♭5 chord?
The A 9♭5 chord (A9♭5) contains 5 notes: A, C#, Eb, G, B. Formula: R-M3-d5-m7-M9.
How is A9♭5 used in music?
A9♭5 is used in jazz, fusion, and contemporary music to add harmonic color. It appears as a dominant or tonic chord depending on context.
What is the scale degree formula for A9♭5?
A9♭5 uses scale degrees 1-3-b5-b7-9, giving it its distinctive sound.
Practice Tips
- Start by placing your thumb on A and spacing remaining fingers across the chord.
- Practice A9♭5 slowly with separate hands before combining.
- Listen carefully to the tension created by the altered tones in this chord.
- Try voicing A9♭5 in different octaves to find the most comfortable position.
- Resolve A9♭5 to a nearby chord to hear its function in context.
Related Tools
Chord FinderLook up any chord — see the notes, hear it, and play along.Chord DrillTimed drills to build speed and recognition across all chord types.Practice RoomPlug in a MIDI keyboard and get real-time feedback on every chord and scale.Circle of FifthsVisualize key relationships, relative minors, and key signatures.MIDI MonitorLive MIDI message stream with note names, velocity, and a scrolling staff.