A♭ ninth, sharp eleven

A♭9(♯11)

Also written G♯9(♯11) · A♭9♭5 · Ab9#11

NotesA♭ · C · E♭ · G♭ · B♭ · D
Formula1 · 3 · 5 · ♭7 · 9 · ♯11
C3D♯11A♭1E♭5G♭♭7B♭9
All its notes, from the root

Lydian dominant with the 9th: 1–3–5–♭7–9–♯11. The ♯11 (D) avoids the clash a natural 11 would make with the 3rd. Add the 13th and it becomes A♭13(♯11).

How pianists voice A♭9(♯11)

Nobody plays a jazz chord in root position. These are the shapes that actually get played — the same ones Cadenza shows when you play the chord.

Shell Left hand

C3A♭1G♭♭7

1 · 3 · ♭7 — root, 3rd and 7th: the three notes that say what the chord is. Left hand, low; everything else is colour.

Rootless A From the 3rd

C3E♭5G♭♭7B♭9

3 · 5 · ♭7 · 9 — no root: the bass player has it. The left-hand voicing of modern jazz piano. Without A♭ underneath, the same keys read as Cø7 — the bass turns them into A♭9(♯11).

Rootless B From the 7th

C3G♭♭7B♭9E♭5

♭7 · 9 · 3 · 5 — the other half of the pair. A and B alternate through a ii–V–I so the hand barely moves.

Drop 2 Two hands

C3E♭5A♭1G♭♭7

5 · 1 · 3 · ♭7 — close position with the second voice from the top dropped an octave: wider, warmer, the standard for chord melody.

Play a chord. See its name.

The free chord finder names whatever you play — on a MIDI keyboard, with your mouse or on your computer keys — with the same engine as Cadenza.

Or let the app follow you.

Cadenza names every chord you play, live, writes what you played as sheet music, and puts the keyboard straight into OBS. The core is free forever.