Bb Sixth-Ninth Chord
Chord Tones: Bb Sixth-Ninth Chord
Symbol: 6/9 — Formula: 1-3-5-6-9
| Degree | Note | Frequency (A=440, Equal) |
|---|---|---|
| 1 | Bb | 466.164 Hz |
| 3 | D | 293.665 Hz |
| 5 | F | 349.228 Hz |
| 6 | G | 391.995 Hz |
| 9 | C | 261.626 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | Bb6/9 |
| All Common Symbols | 6/9 |
| Interval Formula | 1-3-5-6-9 |
| Harmonic Category | bright |
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 | Bb – D – F – G – C | Bb | Bb Sixth-Ninth Chord |
| First Inversion | D – F – G – C – Bb | D | Bb Sixth-Ninth Chord/D |
| Second Inversion | F – G – C – Bb – D | F | Bb Sixth-Ninth Chord/F |
| Third Inversion | G – C – Bb – D – F | G | Bb Sixth-Ninth Chord/G |
| Fourth Inversion | C – Bb – D – F – G | C | Bb Sixth-Ninth Chord/C |
Harmonic Function
The Bb sixth ninth 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 stable harmonic grounding.
The 6/9 chord adds both the sixth and ninth to a major triad without a seventh. It has a rich, colorful sound with a jazz and bossa nova flavor, often used as a final tonic chord.
Common Progressions
The Bb Sixth-Ninth Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
I6/9-IVmaj7
Songs Featuring the Sixth-Ninth Chord
Well-known songs where the Bb Sixth-Ninth Chord — or this chord type — plays a prominent role:
- Chameleon – Herbie Hancock
- Mercy Mercy Mercy – Cannonball Adderley
- Four – Miles Davis
Tuning Frequencies Across Temperaments
Frequencies shown at A=440 Hz. View full temperament data for any note.
| Note | Equal Temp. | Pythagorean | Just Intonation |
|---|---|---|---|
| Bb | 466.164 Hz | 463.538 Hz | 470.926 Hz |
| D | 293.665 Hz | 293.332 Hz | 294.329 Hz |
| F | 349.228 Hz | 347.654 Hz | 348.834 Hz |
| G | 391.995 Hz | 391.111 Hz | 392.438 Hz |
| C | 261.626 Hz | 260.740 Hz | 261.626 Hz |
Scales Containing the Bb Sixth-Ninth Chord
These scales include the Bb Sixth-Ninth Chord as a diatonic or characteristic chord: