22.5 · Sevenths & Jazz

Past the 7th: 9, 11, 13

The 7th came from adding one more skip. Keep going and the odd numbers keep counting: 9, 11, 13. They're just scale tones an octave up (9 is 2, 11 is 4, 13 is 6), added until the whole scale is in the chord. Past 13 there's nothing left to add.

The climb to 13

Take every other note of the scale until you have seven: C E G B D F A is 1 3 5 7 9 11 13. Tap the tones, then hear the chord grow.

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Players rarely play every tone: the root and the colors matter most, and the 11 usually sits out on major chords (it rubs against the 3). Extensions are a menu, not a checklist.

The cadence, upgraded

The ii V I with color on top: ii9, V13, Imaj9. Same roles, same pull, more color in each chord. This is the default voicing in jazz and neo-soul.

Game · How tall is it?

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A C major chord at one of four heights. How far up does it go?

Listen first. Then answer.

Quiz

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The 9th of a chord is the same letter as its…

Score 100% on every quiz and game to complete this lesson. A perfect run sticks: a later miss never undoes it.Same chord, new shape →