A9♭5 — A dominant ninth flat fifth chord
A dominant ninth chord with the fifth flattened. The flat fifth and the ninth together outline a whole-tone scale above the root.
- 1 = A
- 3 = C#
- b5 = Eb
- b7 = G
- 9 = B
- Symbol
- A9♭5
- Root
- A
- Quality
- Dominant ninth flat fifth
- Family
- altered
- Notes
- A C# Eb G B
- Degree formula
1 3 b5 b7 9- Semitones from the root
0 2 4 6 10- Distinct pitch classes
- 5
- Interval structure
- Stacked from the root: 4 semitones, 2 semitones, 4 semitones, 4 semitones
- Notation
- Written 9♭5. An altered dominant in jazz, and the first half of a tritone substitution pair.
- Key
- A · A major / F# minor key signature
Formula
The chord tones in order from the root, with the interval each one forms above it.
| Degree | Note | Semitones | Interval from the root |
|---|---|---|---|
| 1 | A | 0 | Perfect unison |
| 3 | C# | 4 | Major third |
| b5 | Eb | 6 | Tritone |
| b7 | G | 10 | Minor seventh |
| 9 | B | 2 | Major second |
Inversions
An inversion is the same set of notes with a different one in the bass. The last column gives the distance of each note above the bass note, in semitones.
| Inversion | Bass note | Degree in the bass | Notes above the bass | Semitones above the bass |
|---|---|---|---|---|
| root position | A | 1 | A – C# – Eb – G – B | 0 4 6 10 2 |
| first inversion | C# | 3 | C# – Eb – G – B – A | 0 2 6 10 8 |
| second inversion | Eb | b5 | Eb – G – B – A – C# | 0 4 8 6 10 |
| third inversion | G | b7 | G – B – A – C# – Eb | 0 4 2 6 8 |
| fourth inversion | B | 9 | B – A – C# – Eb – G | 0 10 2 4 8 |
Playable voicings
These shapes were found by searching the fretboard of a standard-tuned guitar (E A D G B E) rather than copied from a chord book. The search allows every string to sound or to be muted, rejects any shape with a muted string between two sounding strings, rejects any shape whose fretted notes span more than four frets (a five-fret window), requires every chord tone to be present, and then sorts what remains with root-position shapes first and the most compact, lowest shapes next. The shapes shown are the first six of that ordering; other orderings are possible at the same frets.
| # | Shape (low string first) | Notes | Degrees | Bass | Span (frets) | Sounding strings |
|---|---|---|---|---|---|---|
| 1 | 5-4-5-4-4-5 | A C# G B D# A | 1 3 b7 9 b5 1 | A | 1 | 6 |
| 2 | 5-4-5-4-4-3 | A C# G B D# G | 1 3 b7 9 b5 b7 | A | 2 | 6 |
| 3 | 5-4-5-4-4-7 | A C# G B D# B | 1 3 b7 9 b5 9 | A | 3 | 6 |
| 4 | 5-4-5-6-4-7 | A C# G C# D# B | 1 3 b7 3 b5 9 | A | 3 | 6 |
| 5 | 5-6-5-6-4-7 | A D# G C# D# B | 1 b5 b7 3 b5 9 | A | 3 | 6 |
| 6 | 5-6-5-6-8-7 | A D# G C# G B | 1 b5 b7 3 b7 9 | A | 3 | 6 |
Shape numbers run from the lowest string to the highest, so the left-hand number is the sixth string (low E) in standard tuning. Multiple shapes are listed because a chord can be voiced several ways, and because a lower position is not always the better sounding one.
Related chords and scales
- KeyEverything in A
- ScaleA whole tone
- ChordA9
- ChordA
- ChordA7
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