Lesson 58 · All 12 keys

Half-Diminished 11th Chord Trainer

Learn how a Half-diminished 11th chord is built one semitone-count at a time — a half-diminished 7th chord (Lesson 17) with a 9th and 11th stacked on top — then put it to work with three MIDI exercises: playing all 12 half-Diminished 11th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions that show off its color, in every key.

How a Half-diminished 11th chord is built

A Half-diminished 11th chord — written m11♭5 (e.g. Cm11♭5) — is a 6-note chord: a half-diminished 7th chord (Lesson 17) with a 9th and 11th stacked on top. Every m11♭5 chord — in any of the 12 keys — is built the exact same way, by counting semitones to the right from a root note:

  1. The starting note — this note names the chord.
  2. Count 3 semitones up from the root — the minor 3rd.
  3. Count 3 more semitones up from the 3rd (6 semitones from the root) — the diminished 5th, the same 5th a half-diminished 7th chord (Lesson 17) uses.
  4. Count 4 more semitones up from the 5th (10 semitones from the root) — the minor 7th.
  5. Count 4 more semitones up from the 7th (14 semitones from the root) — the 9th.
  6. Count 3 more semitones up from the 9th (17 semitones from the root — an octave plus a perfect 4th) — the 11th.
Example — Cm11♭5: start on C, count 3 semitones right to reach E♭, count 3 semitones more to reach G♭, count 4 semitones more to reach B♭, count 4 semitones more to reach D, count 3 semitones more to reach F. C‑E♭‑G♭‑B♭‑D‑F is the Cm11♭5 chord.
An extended half-diminished color: the same diminished-5th, minor-7th skeleton as a half-diminished 7th chord (Lesson 17), just with two more colors piled on top — most useful in minor-key ii–V progressions where a plain half-diminished 7th would otherwise appear.

Try it: pick a root and build the chord step by step

Step 1 of 6
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Chord toneNoteSemitones from rootMIDI #

All 12 half-Diminished 11th chords at a glance

ChordRootMinor 3rdDiminished 5thMinor 7th9th11th

This MIDI exercise plays all 12 half-Diminished 11th chords, one after another, moving around the circle of fourths — each chord's root sits a perfect 4th (5 semitones) above the last one: C → F → B♭ → E♭ → A♭ → D♭ → G♭/F♯ → B → E → A → D → G → back to C. Every chord is played as a full 6-note Half-diminished 11th chord (root, minor 3rd, diminished 5th, minor 7th, 9th, 11th together).

Chord 1 of 12
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The 12 chords, in circle-of-fourths order

#ChordRootMinor 3rdDiminished 5thMinor 7th9th11th

Five jazz chord progressions built around the Half-diminished 11th chord. Pick a progression and play it in one key or cycle through all 12.

Key of C
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Progression in C

DegreeChordNotes

Five gospel chord progressions built around the Half-diminished 11th chord. Pick a progression and play it in one key or cycle through all 12.

Key of C
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Progression in C

DegreeChordNotes