Bb Dominant Ninth Chord
Chord Tones: Bb Dominant Ninth Chord
Symbol: 9 — Formula: 1-3-5-♭7-9
| Degree | Note | Frequency (A=440, Equal) |
|---|---|---|
| 1 | Bb | 466.164 Hz |
| 3 | D | 293.665 Hz |
| 5 | F | 349.228 Hz |
| ♭7 | Ab | 415.305 Hz |
| 9 | C | 261.626 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | Bb9 |
| All Common Symbols | 9 |
| Interval Formula | 1-3-5-♭7-9 |
| 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 | Bb – D – F – Ab – C | Bb | Bb Dominant Ninth Chord |
| First Inversion | D – F – Ab – C – Bb | D | Bb Dominant Ninth Chord/D |
| Second Inversion | F – Ab – C – Bb – D | F | Bb Dominant Ninth Chord/F |
| Third Inversion | Ab – C – Bb – D – F | Ab | Bb Dominant Ninth Chord/Ab |
| Fourth Inversion | C – Bb – D – F – Ab | C | Bb Dominant Ninth Chord/C |
Harmonic Function
The Bb dominant 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 dominant ninth chord extends the dominant seventh with a ninth, adding color and richness to one of music's most harmonically active chords. Essential in jazz, blues, and funk.
Common Progressions
The Bb Dominant Ninth Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
V9-Iii9-V9-I
Songs Featuring the Dominant Ninth Chord
Well-known songs where the Bb Dominant Ninth Chord — or this chord type — plays a prominent role:
- Purple Haze – Jimi Hendrix
- What's Going On – Marvin Gaye
- Superstition – Stevie Wonder
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 |
| Ab | 415.305 Hz | 417.657 Hz | 418.601 Hz |
| C | 261.626 Hz | 260.740 Hz | 261.626 Hz |
Scales Containing the Bb Dominant Ninth Chord
These scales include the Bb Dominant Ninth Chord as a diatonic or characteristic chord: