The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped.
F#7 is F#, A#, C# and E — F# with the flat seventh added on top.
It sounds restless and pointed at something. The third and the flat seventh are a tritone apart and each moves by a semitone into the next chord; that is the engine of a cadence, and the whole vocabulary of the blues.

| F# | A# | C# | E |
|---|---|---|---|
| 1 | 3 | 5 | ♭7 |
Dominant — it points a fifth down.
Also written F#dom7 or F# dominant 7. 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#7 has 9 of them, on strings 5-3-2-1 and strings 6-4-3-2, from the 2nd fret up to the 14th — every inversion the chord has: F# in the bass, A# in the bass, C# in the bass and E in the bass. The one to learn first is the C# shape at the 2nd fret.
5 of them sit on strings 6-4-3-2, 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 xx4656 — no barre and low, at the 4th fret. None of the shapes for F#7 uses an open string, so every one of them is movable; the lowest sits at the 2nd fret. 4 of the 6 need a barre. Together they cover the neck from the 2nd fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 242322 | 2nd fret | F#, root position | F# | barred |
| xx4656 | 4th fret | F#, root position | A# | all fretted |
| x9897x | 7th fret | F#, root position | F# | all fretted |
| x-9-11-9-11-9 | 9th fret | F#, root position | C# | barred |
| x-x-11-11-11-12 | 11th fret | C#, 2nd inversion | E | barred |
| 14-13-11-11-11-12 | 11th fret | F#, root position | E | barred |
The same notes rebuilt from scratch give 6 shell, 13 drop 2 and 6 open string voicings, each on its own page.
Tensions. A shell of F#7, root, third and seventh, leaves a string free, and the tones that belong over it are the b9 (G), the 9 (G#), the #9 (G##), the #11 (B#), the b13 (D) and the 13 (D#).
F#7 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#7 → B. 2 voices move by a semitone, and one note is common to both chords.
| In F#7 | 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 |
In which keys. Every note of F#7 belongs to Ab minor (the ♭VII) and B major (the V, the dominant).
Every note of F#7 is in F# mixolydian, F# lydian dominant and F# half-whole diminished.
Change one note of F#7 and you have F# (drop the flat seventh), F#maj7 (the flat seventh becomes a major seventh), F#m7 (the major third becomes a minor third), F#add9 (the flat seventh becomes a ninth), F#6 (the flat seventh becomes a sixth) or F#7sus4 (the major third becomes a fourth).
F#7 is a dominant chord — root, major third, fifth, minor seventh. Dominant seventh chords on every root.
On F#7’s sound and use this page follows Edward Aldwell & Carl Schachter, Harmony and Voice Leading (Schirmer / Cengage, 4th ed., 2011). 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.