CadenzaC thirteenth, flat nine
C13(♭9)
Also written C13b9
♭9 (D♭) and 13 (A) together — the half-whole diminished dominant. The 13, ♭9 and 3 make an A major triad, so it is played as A over C7.
How pianists voice C13(♭9)
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.
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 · ♭9 · 3 · 13 — an A major triad in the right hand (13, ♭9 and 3) over the root, 3rd and ♭7 in the left. One familiar shape, all the tension.
Thirteenth, flat nine chords in every key
Every C chord
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