F#
F#7b5
Notes
F# · A# · C · E
Intervals
- RootF# (1P)
- Major 3rdA# (3M)
- Diminished 5thC (5d)
- Minor 7thE (7m)
Fretboard
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About
The F♯7♭5 (F♯–A♯–C–E) lowers the fifth, replacing the stable perfect fifth with a tritone above the root. Combined with the tritone already present between 3rd and ♭7, the chord contains two tritones — making it extremely unstable and dissonant. In jazz, 7♭5 functions as an altered dominant with a particular flavour of harmonic restlessness. The 3rd, ♭7, and ♭5 are all essential; the C is the defining alteration, and omitting it leaves a plain F♯7. It resolves typically to B or Bm. Compared to standard F♯7, 7♭5 is considerably more harmonically tense.
Similar chords
Chords sharing two or more notes with this one, ranked by overlap.
Scales containing this chord
- F♯ Whole Tone (deg 1)
- A♭ Whole Tone (deg 6)
- B♭ Diminished (deg 6)
- B♭ Whole Tone (deg 5)
- C Whole Tone (deg 4)
- D Whole Tone (deg 3)
- D♭ Diminished (deg 4)
- D♭ Harmonic Minor (IV)
- D♭ Melodic Minor (IV)
- E Diminished (deg 2)
- E Whole Tone (deg 2)
- G Diminished (deg 8)
- G Melodic Minor (VII)
Scales whose notes include every chord tone. Roman numeral marks the chord root’s position in the scale; dashed badges aren’t linked yet.