The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped.
F#9 is F#, A#, C#, E and G# — F#7 with the ninth stacked on top.
It sounds bright and full, still clearly pulling. The ninth adds height without softening the tritone underneath it, which is why funk and soul comp on this rather than on a plain 7.

| F# | A# | C# | E | G# |
|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | 9 |
Dominant — the same pull as a 7, with more colour.
Also written F#dom9 or F# dominant 9. The same chord either way; which spelling you meet depends on who wrote the chart.
The same operation one voice further down: the third voice from the top falls an octave and becomes the bass.
That leaves a bigger hole under the top three notes, so a string gets skipped: the muted string in the middle is the shape, not a mistake.
F#9 has 8 of them, on strings 5-3-2-1 and strings 6-4-3-2, from open position up to the 11th — every inversion the chord has: F# in the bass, A# in the bass, E in the bass and G# in the bass. The one to learn first is the A# shape at the nut.
4 of them sit on strings 5-3-2-1, so you can run the inversions up one set without changing strings — which is the whole reason to learn them as a family rather than as separate grips.
Start with 2121xx — no barre and down at the nut. None of the shapes for F#9 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 6 of the 9 need a barre. Together they cover the neck from the 1st fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 2121xx | 1st fret | F#, root position | G# | all fretted |
| 242324 | 2nd fret | F#, root position | G# | barred |
| 242124 | 1st fret | F#, root position | G# | barred |
| xx4354 | 3rd fret | F#, root position | G# | all fretted |
| 6x4654 | 4th fret | A#, 1st inversion | G# | all fretted |
| x98999 | 8th fret | F#, root position | C# | barred |
| x-11-11-11-11-12 | 11th fret | G#, 9th in the bass | E | barred |
| 14-11-11-13-11-12 | 11th fret | F#, root position | E | barred |
| 14-13-14-13-14-x | 13th fret | F#, root position | C# | barred |
The same notes rebuilt from scratch give 4 shell, 13 drop 2, 14 rootless and 1 open string voicings, each on its own page.
Tensions. A shell of F#9, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (B#), the b13 (D) and the 13 (D#).
F#9 is the V of B, and that is where it goes if it goes anywhere: the third and the flat seventh are a tritone apart, and both resolve by a semitone into B.
Voice by voice, F#9 → B. 2 voices move by a semitone, and one note is common to both chords.
| In F#9 | Moves | In B |
|---|---|---|
| F#, the root | stays where it is | F#, the fifth |
| A#, the major third | rises a semitone | B, the root |
| C#, the fifth | falls a whole tone | B, the root |
| E, the flat seventh | falls a semitone | D#, the major third |
| G#, the ninth | falls a whole tone | F#, the fifth |
In which keys. Every note of F#9 belongs to Ab minor (the ♭VII) and B major (the V, the dominant).
Every note of F#9 is in F# mixolydian and F# lydian dominant.
Change one note of F#9 and you have F#maj9 (the flat seventh becomes a major seventh), F#m9 (the major third becomes a minor third), F#add9 (drop the flat seventh), F#69 (the flat seventh becomes a sixth), F#7 (drop the ninth) or F#9b5 (the fifth becomes a flat fifth).
F#9 is a dominant chord — root, major third, fifth, minor seventh. Dominant seventh chords on every root.
On F#9’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.