A#9♭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 = E
- b7 = G#
- 9 = B#
- Symbol
- A#9♭5
- Root
- A#
- Quality
- Dominant ninth flat fifth
- Family
- altered
- Notes
- A# C## E 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# · Bb major / G minor key signature
Fingering charts
The library holds 6 fingerings of this chord and all of them are shown, in the library’s own order. Several fingerings of one chord is normal: the same notes can be stopped at different positions and on different strings.
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 | E | 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## – E – G# – B# | 0 4 6 10 2 |
| first inversion | C## | 3 | C## – E – G# – B# – A# | 0 2 6 10 8 |
| second inversion | E | b5 | E – G# – B# – A# – C## | 0 4 8 6 10 |
| third inversion | G# | b7 | G# – B# – A# – C## – E | 0 4 2 6 8 |
| fourth inversion | B# | 9 | B# – A# – C## – E – 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 | 6-5-6-5-5-6 | A# D G# C E A# | 1 3 b7 9 b5 1 | A# | 1 | 6 |
| 2 | 6-5-6-5-5-4 | A# D G# C E G# | 1 3 b7 9 b5 b7 | A# | 2 | 6 |
| 3 | 6-5-6-5-5-8 | A# D G# C E C | 1 3 b7 9 b5 9 | A# | 3 | 6 |
| 4 | 6-5-6-7-5-8 | A# D G# D E C | 1 3 b7 3 b5 9 | A# | 3 | 6 |
| 5 | 6-7-6-7-5-8 | A# E G# D E C | 1 b5 b7 3 b5 9 | A# | 3 | 6 |
| 6 | 6-7-6-7-9-8 | A# E G# D G# C | 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
- ChordA#9
- ChordA#
- ChordA#7
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