B♭ Diminished Seventh Chord
Chord Tones: B♭ Diminished Seventh Chord
Symbol: dim7, °7 — Formula: 1-♭3-♭5-𝄫7
| Degree | Note | Frequency (A=440, Equal) |
|---|---|---|
| 1 | B♭4 | 466.164 Hz |
| ♭3 | D♭4 | 277.183 Hz |
| ♭5 | E4 | 329.628 Hz |
| 𝄫7 | G4 | 391.995 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | B♭dim7 |
| All Common Symbols | dim7, °7 |
| Interval Formula | 1-♭3-♭5-𝄫7 |
| Harmonic Category | tense |
Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.
Inversions
| Inversion | Notes (low to high) | Bass Note | Slash Notation |
|---|---|---|---|
| Root Position | B♭4 – D♭4 – E4 – G4 | B♭ | B♭ Diminished Seventh Chord |
| First Inversion | D♭4 – E4 – G4 – B♭4 | D♭ | B♭ Diminished Seventh Chord/D♭ |
| Second Inversion | E4 – G4 – B♭4 – D♭4 | E | B♭ Diminished Seventh Chord/E |
| Third Inversion | G4 – B♭4 – D♭4 – E4 | G | B♭ Diminished Seventh Chord/G |
Harmonic Function
The B♭ diminished seventh chord commonly functions as the subtonic (♭VII) in C major or subdominant in F major. Its harmonic role varies by key — in major keys it provides extended harmonic tension.
The diminished seventh chord consists of four equally-spaced minor thirds, creating a symmetrical, highly dissonant chord. It is used as a dramatic pivot chord and in chromatic passing harmony.
Common Progressions
The B♭ Diminished Seventh Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
Songs Featuring the Diminished Seventh Chord
Well-known songs where the B♭ Diminished Seventh Chord — or this chord type — plays a prominent role:
- While My Guitar Gently Weeps – Beatles
- Georgia on My Mind – Ray Charles
- Sophisticated Lady – Duke Ellington
Tuning Frequencies Across Temperaments
Frequencies shown at A=440 Hz. View full temperament data for any note.
| Note | Equal Temp. | Pythagorean | Just Intonation |
|---|---|---|---|
| B♭4 | 466.164 Hz | 463.538 Hz | 470.926 Hz |
| D♭4 | 277.183 Hz | 278.437 Hz | 279.067 Hz |
| E4 | 329.628 Hz | 330.001 Hz | 327.032 Hz |
| G4 | 391.995 Hz | 391.111 Hz | 392.438 Hz |
Scales Containing the B♭ Diminished Seventh Chord
These scales include the B♭ Diminished Seventh Chord as a diatonic or characteristic chord: