F#7b9 F# dominant seventh flat nine chord
- Notes
- F# A# C# E G
- Formula
- 1 3 5 b7 b9
- Semitones
- 0 4 7 10 13 above the root
- Also written
- Gb7b9 (Gb Bb Db Fb Abb)
- Other symbols
- F#7(b9), F#7-9
F# to A# is a major third (4 semitones), A# to C# is a minor third (3 semitones), C# to E is a minor third (3 semitones), E to G is a minor third (3 semitones). A dominant seventh with a flattened ninth, G, a half step (plus an octave) above the root. It is the sharpest-sounding of the common dominant chords and pulls hard towards a minor tonic.
F#7b9 on the piano
Root position from F#4: F#4, A#4, C#5, E5, G5. Middle C is C4.
F#7b9 on the guitar
Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has F# as its lowest note.
2 x 2 3 2 3 (low E to high e)
Sounds F#2 E3 A#3 C#4 G4
x 9 8 9 8 x (low E to high e)
Sounds F#3 A#3 E4 G4, fifth left out
The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play dominant seventh flat nine chords on other roots.
Inversions of F#7b9
An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.
| Position | Notes, bass first | Named | Listen |
|---|---|---|---|
| Root position | F# A# C# E G | F#7b9 | |
| 1st inversion | A# C# E G F# | F#7b9/A# | |
| 2nd inversion | C# E G F# A# | F#7b9/C# | |
| 3rd inversion | E G F# A# C# | F#7b9/E | |
| 4th inversion | G F# A# C# E | F#7/G (also read as F#7b9/G) |
Where F#7b9 fits
F#7b9 is V7b9 in B minor. Its upper four notes A# C# E G are A#dim7, so F#7b9 and that diminished seventh are interchangeable over a F# bass. The flat ninth G falls a half step to the fifth of Bm.