CadenzaC seventh, sharp nine, flat thirteen
C7(♯9♭13)
Also written C7alt (often) · C7#9b13
The altered sound in its most common form: ♯9 (D♯) and ♭13 (A♭) over the 3rd and ♭7. Charts often write it simply as C7alt. V of F minor.
How pianists voice C7(♯9♭13)
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
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
3 · ♭13 · ♭7 · ♯9 — no root: the bass player has it. The left-hand voicing of modern jazz piano. Without C underneath, the same keys read as Emaj7(♯11) — the bass turns them into C7(♯9♭13).
Rootless B From the 7th
♭7 · ♯9 · 3 · ♭13 — the other half of the pair. A and B alternate through a ii–V–I so the hand barely moves.
Drop 2 Two hands
♭13 · 1 · 3 · ♭7 — close position with the second voice from the top dropped an octave: wider, warmer, the standard for chord melody.
Upper structure ♭VI Triad over shell
1 · 3 · ♭7 · 1 · ♯9 · ♭13 — an A♭ major triad in the right hand (♭13, root and ♯9) over the root, 3rd and ♭7 in the left. One familiar shape, all the tension.
Seventh, sharp nine, flat thirteen chords in every key
Every C chord
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.