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B♭ 9sus4

Also known as A♯ 9sus4
Same keys, different spelling.
Open A♯ 9sus4 →Same chord, spelled with sharpsWhat are enharmonics? →Why one chord has two names
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Listen plays the chord. Play Along lights up each note in order so you can follow.

B♭9sus4
B♭ – E♭ – F – A♭ – C
Formula:R-P4-P5-m7-M9
Intervals:P1-P4-P5-m7-M9
Scale Degrees:1-4-5-b7-9

Introduction

Bb 9sus4 piano chord, root position — Bb, Eb, F, Ab, C
The Bb 9sus4 chord in root position on a piano keyboard, notes Bb, Eb, F, Ab, C.

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.

Notes

Notes:B♭ – E♭ – F – A♭ – C

Key Signature

The key of Bb 9sus4 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.

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 diatonic triads built on each degree of the B♭ major scale:

C
D
E
F
G
A
B
C
D
E
F
G
A
B
I — B♭ Major (major)
DegreeNumeralChordQuality
1IB♭ MajorMajor
2iiC MinorMinor
3iiiD MinorMinor
4IVE♭ MajorMajor
5VF MajorMajor
6viG MinorMinor
7vii°A DiminishedDiminished

Theory: Intervals

Formula: R-P4-P5-m7-M9
Intervals: P1-P4-P5-m7-M9

The B♭ 9sus4 is built by stacking intervals from the root note. The formula R-P4-P5-m7-M9 describes the scale degrees used. The intervals P1-P4-P5-m7-M9 show the distance between each note in the chord.

B♭ 9sus4 — Frequently Asked Questions

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.

Practice Tips

  • Start by placing your thumb on Bb and spacing remaining fingers across the chord.
  • Practice Bb9sus4 slowly with separate hands before combining.
  • Listen carefully to the tension created by the altered tones in this chord.
  • Try voicing Bb9sus4 in different octaves to find the most comfortable position.
  • Resolve Bb9sus4 to a nearby chord to hear its function in context.

Related Tools

Chord FinderLook up any chord — see the notes, hear it, and play along.Chord DrillTimed drills to build speed and recognition across all chord types.Practice RoomPlug in a MIDI keyboard and get real-time feedback on every chord and scale.Circle of FifthsVisualize key relationships, relative minors, and key signatures.MIDI MonitorLive MIDI message stream with note names, velocity, and a scrolling staff.