B
B7b5
Notes
B · D# · F · A
Intervals
- RootB (1P)
- Major 3rdD# (3M)
- Diminished 5thF (5d)
- Minor 7thA (7m)
Fretboard
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About
The B7♭5 (B–D♯–F–A) 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 F is the defining alteration, and omitting it leaves a plain B7. It resolves typically to E or Em. Compared to standard B7, 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
- B Whole Tone (deg 1)
- A Diminished (deg 2)
- A Whole Tone (deg 2)
- C Diminished (deg 8)
- C Melodic Minor (VII)
- D♭ Whole Tone (deg 6)
- E♭ Whole Tone (deg 5)
- F Whole Tone (deg 4)
- F♯ Diminished (deg 4)
- F♯ Melodic Minor (IV)
- G Whole Tone (deg 3)
Scales whose notes include every chord tone. Roman numeral marks the chord root’s position in the scale; dashed badges aren’t linked yet.