The B♭ 7♭9♯11 chord is a six-note chord made up of B♭, D, F, A♭, C♭, and E. It is built from a root, major third, perfect fifth, minor seventh, minor ninth, and augmented eleventh.
Construction
B♭ 7♭9♯11 = Root + Major 3rd + Perfect 5th + Minor 7th + Minor 2nd + Diminished 5th = B♭ · D · F · A♭ · C♭ · E
| Note | Interval | Degree |
|---|---|---|
| B♭ | Root | 1 |
| D | Major 3rd | 3 |
| F | Perfect 5th | 5 |
| A♭ | Minor 7th | ♭7 |
| C♭ | Minor 2nd | ♭9 |
| E | Diminished 5th | ♭5 |
Key Signature
A chord has no key signature of its own, but the B♭ 7♭9♯11 is the tonic (I) chord of Bb Major, whose key signature has 2 flats (B♭, E♭).
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.
B♭E♭A♭D♭G♭C♭F♭
Mnemonic: Battle Ends And Down Goes Charles’ Father
Chords in the Key of B♭ Major
These are the triads built on each degree of the B♭ major scale:
Same Notes, Other Names
The notes B♭ – D – F – A♭ – C♭ – E aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell:
B♭ 7♭9♯11 — Frequently Asked Questions
What is the B♭ 7♭9♯11 chord on piano?
The B♭ 7♭9♯11 chord contains the notes B♭ – D – F – A♭ – C♭ – E. On piano, play these notes together to sound the chord.
What notes are in the Bb 7♭9♯11 chord?
The Bb 7♭9♯11 chord (Bb7♭9♯11) contains 6 notes: Bb, D, F, Ab, B, E. Formula: R-M3-P5-m7-m9-A11.
How is Bb7♭9♯11 used in music?
Bb7♭9♯11 is used in jazz, fusion, and contemporary music to add harmonic color. It appears as a dominant or tonic chord depending on context.
What is the scale degree formula for Bb7♭9♯11?
Bb7♭9♯11 uses scale degrees 1-3-5-b7-b9-#11, giving it its distinctive sound.