Bb7♭5#9 — Bb dominant seventh flat fifth sharp ninth chord

A dominant seventh chord with both the fifth and the ninth altered: the flat fifth and the sharp ninth are the two notes that make the chord fully altered.

1 = Bb
3 = D
b5 = Fb
b7 = Ab
#9 = C#

Symbol: Bb7♭5#9
Root: Bb
Quality: Dominant seventh flat fifth sharp ninth
Family: altered
Notes: Bb D Fb Ab C#
Degree formula: 1 3 b5 b7 #9
Semitones from the root: 0 3 4 6 10
Distinct pitch classes: 5
Interval structure: Stacked from the root: 4 semitones, 2 semitones, 4 semitones, 5 semitones
Notation: Written 7♭5#9 or 7♭5(#9). A whole-tone dominant, resolving a fifth down.
Key: Bb · Bb major / G minor key signature

Bb7♭5#9 chord fingering chart, six strings, frets marked — Bb7♭5#9 — fingering chart Diagram: Will Chan

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	Bb	0	Perfect unison
3	D	4	Major third
b5	Fb	6	Tritone
b7	Ab	10	Minor seventh
#9	C#	3	Minor third

Degree

Note

Semitones

Interval from the root

Perfect unison

Major third

Tritone

Minor seventh

Minor third

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	Bb	1	Bb – D – Fb – Ab – C#	0 4 6 10 3
first inversion	D	3	D – Fb – Ab – C# – Bb	0 2 6 11 8
second inversion	Fb	b5	Fb – Ab – C# – Bb – D	0 4 9 6 10
third inversion	Ab	b7	Ab – C# – Bb – D – Fb	0 5 2 6 8
fourth inversion	C#	#9	C# – Bb – D – Fb – Ab	0 9 1 3 7

Inversion

Bass note

Degree in the bass

Notes above the bass

Semitones above the bass

root position

Bb – D – Fb – Ab – C#

0 4 6 10 3

first inversion

D – Fb – Ab – C# – Bb

0 2 6 11 8

second inversion

Fb – Ab – C# – Bb – D

0 4 9 6 10

third inversion

Ab – C# – Bb – D – Fb

0 5 2 6 8

fourth inversion

C# – Bb – D – Fb – Ab

0 9 1 3 7

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	6-5-6-6-5-6 (6→1)	Bb D Ab Db E Bb	1 3 b7 #9 b5 1	Bb	1	6
2	6-5-6-6-5-4 (6→1)	Bb D Ab Db E Ab	1 3 b7 #9 b5 b7	Bb	2	6
3	6-4-6-7-5-4 (6→1)	Bb Db Ab D E Ab	1 #9 b7 3 b5 b7	Bb	3	6
4	6-4-6-7-5-6 (6→1)	Bb Db Ab D E Bb	1 #9 b7 3 b5 1	Bb	3	6
5	6-7-6-7-9-9 (6→1)	Bb E Ab D Ab Db	1 b5 b7 3 b7 #9	Bb	3	6
6	6-7-8-7-9-9 (6→1)	Bb E Bb D Ab Db	1 b5 1 3 b7 #9	Bb	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 Bbscale, chords and neck map for this root
ScaleBb whole tonethe scale this chord comes from
ChordBb7♭9the dominant seventh flat ninth it extends
ChordBbthe triad underneath it
ChordBb7the seventh chord on this root

Everything in Bb · All chords

KeyKey of BbBb C D Eb F G A · Bb major / G minor
ScaleBb whole tone6 notes · 1 2 3 #4 #5 b7
ChordBb7♭9 — Dominant seventh flat ninth1 3 5 b7 b9 · Bb D F Ab Cb
ChordBb — Major1 3 5 · Bb D F
ChordBb7 — Dominant seventh1 3 5 b7 · Bb D F Ab
ChordBb7b5 — Dominant seventh flat five1 3 b5 b7 · Bb D Fb Ab
ChordBb7#11 — Dominant seventh sharp eleventh1 3 5 b7 #11 · Bb D F Ab E
ChordBb7#5 — Dominant seventh sharp fifth1 3 #5 b7 · Bb D F# Ab

Everything in this key: Bb · Chords · Theory Atlas