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Chord and Fret

Bb9 — dominant ninth

Also written A#9 — the same chord, spelled the other way.

Notes in Bb9: Bb – D – F – Ab – CFormula: 1 – 3 – 5 – b7 – 9

In the formula, the numbers count steps of the major scale starting from the note that names the chord; "b" lowers a half step, "#" raises one — and a slash names the bass note.

The 9 is the dominant chord with the ninth. It keeps the dominant function and adds color and breadth.

The same chord on all four instruments

Bb9, x 1 0 1 1 1Bb91234×BbDAbCF
Guitar
Bb9, x 1 0 1 1 1Bb91234×BbDAbCF
Electric guitar
Bb9, 8 7 9 10Bb972134BbDAbC
Cavaquinho
Bb9, 3 0 4 5Bb9123BbCAbD
Ukulele

Where to use it: Blues, funk, choro and broader dominants.

Every region of the neck hides more shapes of Bb9. In Chord and Fret, you hear every shape strummed string by string, in each instrument's own voice; open every variation on the neck, grouped by bass note; and change the tuning — the shape rewrites itself. Start free. Unlock everything with Pro. Plays offline.

See the whole neck in Chord and Fret →

Part of the Extended family.

Other chords in this family

Bbmaj9A#m9A#m11Bb13Bbmaj9(#11)Bb11Bbmaj11Bbmaj13Bbm13Bbm(maj9)

See all chord types and qualities →