Construction
| Note | Interval | Degree |
|---|---|---|
| B♭ | Root | 1 |
| D | Major 3rd | 3 |
| F | Perfect 5th | 5 |
| A | Major 7th | 7 |
| C | Major 2nd | 9 |
Fingering
| Note | Key color | Right hand | Left hand |
|---|---|---|---|
| B♭ | black | thumb (1) | little finger (5) |
| D | white | index finger (2) | ring finger (4) |
| F | white | middle finger (3) | middle finger (3) |
| A | white | ring finger (4) | index finger (2) |
| C | white | little finger (5) | thumb (1) |
Right hand: thumb (1) on B♭, index finger (2) on D, middle finger (3) on F, ring finger (4) on A, little finger (5) on C.
Left hand: little finger (5) on B♭, ring finger (4) on D, middle finger (3) on F, index finger (2) on A, thumb (1) on C.
Key Signature
A chord has no key signature of its own, but the B♭ Major 9th is the tonic (I) chord of B♭ Major, whose key signature has 2 flats (B♭, E♭).
Order of flats
Flats are added in a fixed order — the reverse of the sharp order. Each new flat key adds the next flat on the list.
Mnemonic: Battle Ends And Down Goes Charles’ Father
Chords in the Key of B♭ Major
These are the triads built on each degree of B♭ Major:
Scales That Include the B♭ Major 9th
- Bb Major (I)
- F Major (IV)
- D Minor (VI)
- G Minor (III)
- C Dorian (VII)
- D Phrygian (VI)
- Eb Lydian (V)
- F Mixolydian (IV)
B♭ Major 9th : Frequently Asked Questions
What is the B♭ Major 9th chord on piano?
What notes are in the Bb Major 9th chord?
How does Bbmaj9 differ from Bb9?
How is Bbmaj9 used in music?
What songs use Major 9th chords?
How does Bbmaj9 differ from Bbadd9?
Do I need to play all five notes?
B♭ Major 9th in detail
Exact
Every pitch class is present and nothing outside the chord is added.
| Type | Notes | Semitones | Span | Omissions and additions | Set relation | Fit |
|---|---|---|---|---|---|---|
| Close, root position | B♭3 D4 F4 A4 C5 | 14 | 193 mm | none | identical | |
| Close, first inversion | D4 F4 A4 B♭4 C5 | 10 | 138 mm | none | identical | |
| Close, second inversion | F4 A4 B♭4 C5 D5 | 9 | 124 mm | none | identical | |
| Close, third inversion | A4 B♭4 C5 D5 F5 | 8 | 110 mm | none | identical | |
| Close, fourth inversion | C4 D4 F4 A4 B♭4 | 10 | 138 mm | none | identical | |
| Drop 2 | A3 B♭3 D4 F4 C5 | 15 | 206 mm | none | identical | |
| Drop 3 | F3 B♭3 D4 A4 C5 | 19 | 261 mm | none | identical | |
| Drop 2 and 4 | D3 A3 B♭3 F4 C5 | 22 | 303 mm | none | identical |
Reduced
A subset of the pitch classes: the identity is incomplete rather than altered.
| Type | Notes | Semitones | Span | Omissions and additions | Set relation | Fit |
|---|---|---|---|---|---|---|
| Shell, root 9 3 | B♭2 C4 D4 | 16 | 220 mm | omits F | subset | |
| Guide tones, 3 and 9 | D4 C5 | 10 | 138 mm | omits B♭ and F | subset | |
| Rootless close | D4 F4 A4 C5 | 10 | 138 mm | omits B♭ | subset |
Spans are measured centre to centre at a 165 mm octave (standard keyboard geometry).
| Position | Bass note | Notes in order | Figured bass | Semitones | Span |
|---|---|---|---|---|---|
| Root position | B♭ | B♭3, D4, F4, A4, C5 | 9 | 14 | 193 mm |
| First inversion: B♭maj9/D | D | D4, F4, A4, B♭4, C5 | 7/6/5 | 10 | 138 mm |
| Second inversion: B♭maj9/F | F | F4, A4, B♭4, C5, D5 | 7/4/3 | 9 | 124 mm |
| Third inversion: B♭maj9/A | A | A4, B♭4, C5, D5, F5 | 7/4/2 | 8 | 110 mm |
| Fourth inversion: B♭maj9/C | C | C4, D4, F4, A4, B♭4 | 9/7/5 | 10 | 138 mm |
One position per chord tone in the bass. Spans are for close position: voiced inversions appear under Voicings.
| Progression | Key | Role | Sequence | Voice leading |
|---|
Root motion, common tones and voice displacement are computed from pitch class sets. Roman numerals follow common practice functional harmony.
Change one note
Chords a single note away, and what moving that note does.
| Chord | Change | Formula | Common tones |
|---|---|---|---|
| B♭maj7 | drops C | 1 3 5 7 | 4 |
| B♭add9 | drops A | 1 3 5 9 | 4 |
| B♭9 | A becomes A♭ | 1 3 5 ♭7 9 | 4 |
| B♭7 | A, C becomes A♭ | 1 3 5 ♭7 | 3 |
| B♭mMaj7 | D, C becomes D♭ | 1 ♭3 5 7 | 3 |
| B♭6 | A, C becomes G | 1 3 5 6 | 3 |
| B♭m9 | D, A becomes D♭, A♭ | 1 ♭3 5 ♭7 9 | 3 |
Frequencies
| Note | MIDI | Frequency |
|---|---|---|
| B♭3 | 58 | 233.08 Hz |
| D4 | 62 | 293.66 Hz |
| F4 | 65 | 349.23 Hz |
| A4 | 69 | 440.00 Hz |
| C5 | 72 | 523.25 Hz |
Reference pitch A440, 12-TET, close root position.
Set theory: prime form, Forte number, interval vector
- Absolute pitch class set
- {10, 2, 5, 9, 0}
- Normal order
- [9, 10, 0, 2, 5]
- Prime form
- (01358)
- Forte number
- not claimed for this cardinality
- Interval vector
- <122230>
| Pair | Interval | Semitones | Interval class |
|---|---|---|---|
| B♭ to D | Major third | 4 | 4 |
| B♭ to F | Perfect fifth | 7 | 5 |
| B♭ to A | Major seventh | 11 | 1 |
| B♭ to C | Major ninth | 14 | 2 |
| D to F | Minor third | 3 | 3 |
| D to A | Perfect fifth | 7 | 5 |
| D to C | Minor seventh | 10 | 2 |
| F to A | Major third | 4 | 4 |
| F to C | Perfect fifth | 7 | 5 |
| A to C | Minor third | 3 | 3 |
Where these facts come from
Every value on this page is derived from the note formula for a major 9th applied to the root B♭, using standard music theory. Nothing here is hand-entered per chord, so the notes, intervals, inversions and frequencies cannot drift out of agreement with each other. Pitches assume 12-TET at A440.