The B♭ 9sus4 chord is a five-note chord made up of B♭, E♭, F, A♭, and C. It is built from a root, perfect fourth, perfect fifth, minor seventh, and major ninth.
Construction
B♭ 9sus4 = Root + Perfect 4th + Perfect 5th + Minor 7th + Major 2nd = B♭ · E♭ · F · A♭ · C
| Note | Interval | Degree |
|---|---|---|
| B♭ | Root | 1 |
| E♭ | Perfect 4th | 11 |
| F | Perfect 5th | 5 |
| A♭ | Minor 7th | ♭7 |
| C | Major 2nd | 9 |
Key Signature
A chord has no key signature of its own, but the B♭ 9sus4 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♭ – E♭ – F – A♭ – C aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell:
B♭ 9sus4 — Frequently Asked Questions
What is the B♭ 9sus4 chord on piano?
The B♭ 9sus4 chord contains the notes B♭ – E♭ – F – A♭ – C. On piano, play these notes together to sound the chord.
What notes are in the Bb 9sus4 chord?
The Bb 9sus4 chord (Bb9sus4) contains 5 notes: Bb, Eb, F, Ab, C. Formula: R-P4-P5-m7-M9.
How is Bb9sus4 used in music?
Bb9sus4 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 Bb9sus4?
Bb9sus4 uses scale degrees 1-4-5-b7-9, giving it its distinctive sound.