Chords
Bb Dominant sharp ninth
Bb · D · F · Ab · C#
The Hendrix chord — a dominant seventh with a raised ninth, major and minor thirds colliding on purpose.
Bb Dominant sharp ninth
Bb · D · F · Ab · C#
Voicings on the piano
| Voicing | Notes | Play it on your instrument |
|---|---|---|
| Closed, root position | Bb3 · D4 · F4 · Ab4 · C#5 | |
| Open (drop 2) | Ab3 · Bb3 · D4 · F4 · C#5 | |
| Shell | Bb3 · D4 · Ab4 | |
| Rootless | D4 · Ab4 · C#5 |
Tap a key or a fret to hear it.
Anatomy
Bb Dominant sharp ninth (Bb7#9) contains the notes Bb · D · F · Ab · C#, each with a role measured as an interval from the root.
Read on: how triads are built · seventh chords · extensions
Inversions
An inversion of Bb Dominant sharp ninth puts a chord tone other than Bb in the bass; the name after the slash is that bass note.
Where it lives
The keys and the scales Bb Dominant sharp ninth belongs to.
In which keys
Bb Dominant sharp ninth is not diatonic to any major or minor key: at least one of its notes lies outside every one of them.
Scales that contain it
Bb Dominant sharp ninth fits inside these scales, each built on Bb.
- Bb Half-Whole DiminishedBb · Cb · Db · D · E · F · G · Ab
- Bb Hungarian MajorBb · C# · D · E · F · G · Ab
- Bb FlamencoBb · Cb · Db · D · E · F · Ab
- Bb Spanish HeptatonicBb · Cb · Db · D · Eb · F · Gb · Ab
- Bb Bebop MinorBb · C · Db · D · Eb · F · G · Ab
- Bb Kafi RagaBb · Db · D · Eb · F · G · Ab · A
- Bb Composite BluesBb · C · Db · D · Eb · Fb · F · G · Ab
- Bb Messiaen's Mode #3Bb · C · Db · D · E · F · Gb · Ab · A
Understanding the Bb Dominant sharp ninth chord
Names and symbols
Bb7#9 is the chord symbol for Bb Dominant sharp ninth.
How it is built
On Bb it is Bb · D · F · Ab · C#, stacking 1P · 3M · 5P · 7m · 9A. The ♯9 is enharmonically the minor third, so the chord contains both thirds at once.
How it is used
That collision is the sound of the blues written into a single chord — the blue third rubbing against the major third of the dominant. Purple Haze made it famous; funk, hard bop and soul have used it ever since.
Learn this properly
Chapter 17: Theory in StylesCommon questions
- What notes are in Bb7#9?
- Bb7#9 contains Bb · D · F · Ab · C#. Name any set of notes with the chord identifier.
- Why is it called the Hendrix chord?
- Purple Haze opens on E7♯9, and the association stuck. The chord predates him, but he made it a signature.
- Why does a ♯9 work over a major third?
- The ♯9 is enharmonically the minor third — the blue note. Hearing both at once is exactly what blues-derived harmony does.
- What notes are in the Bb Dominant sharp ninth chord?
- The Bb Dominant sharp ninth chord contains the notes Bb · D · F · Ab · C#: the root Bb with the intervals 1P, 3M, 5P, 7m, 9A stacked above it. Play them together for the chord or one after another for an arpeggio. The lowest note is normally Bb, but any chord tone can take the bass in an inversion.
- What intervals make up the Bb Dominant sharp ninth chord?
- Measured from Bb, the Bb Dominant sharp ninth chord stacks the intervals 1P, 3M, 5P, 7m, 9A. The quality of the third and of the seventh, if there is one, is what gives the chord its character; the rest of the notes colour it. Every interval in the formula links to its own page, with its sound.