Lesson 35 · All 12 keys

Dominant 7♭9 Chord Trainer

Learn how a Dominant 7♭9 chord is built one semitone-count at a time — a plain dominant 7th chord (Lesson 13) with its 9th lowered a semitone instead of left natural — then put it to work with three MIDI exercises: playing all 12 Dominant 7♭9 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions that show off its color, in every key.

How a Dominant 7♭9 chord is built

A Dominant 7♭9 chord — written 7♭9 (e.g. C7♭9) — is a 5-note chord: a plain dominant 7th chord (Lesson 13) with its 9th lowered a semitone instead of left natural. Every 7♭9 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 4 semitones up from the root — the major 3rd.
  3. Count 3 more semitones up from the 3rd (7 semitones from the root) — the perfect 5th.
  4. Count 3 more semitones up from the 5th (10 semitones from the root) — the minor 7th.
  5. Count 3 more semitones up from the 7th (13 semitones from the root — an octave plus a half step) — the ♭9th, a dominant 9th (Lesson 32) lowered a semitone.
Example — A7♭9: start on A, count 4 semitones right to reach C♯, 3 more to reach E, 3 more to reach G, then 3 more to reach B♭ (an octave and a half step above the root). A‑C♯‑E‑G‑B♭ is the A7♭9 chord.
The ♭9th is one of the most classic tension tones in all of jazz and gospel harmony — it appears constantly in ii–V–I progressions, especially when the V chord resolves down to a minor tonic. Watch the spelling: a ♭9 is a half step above the octave, not a whole step like a plain 9th, which is exactly what gives this chord its tighter, more dissonant pull toward home.

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

Step 1 of 5
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Chord toneNoteSemitones from rootMIDI #

All 12 Dominant 7♭9 chords at a glance

ChordRoot+4 semitones → Major 3rd+3 semitones → Perfect 5th+3 semitones → Minor 7th+3 semitones → ♭9th

This MIDI exercise plays all 12 Dominant 7♭9 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 5-note Dominant 7♭9 chord (root, major 3rd, perfect 5th, minor 7th, ♭9th together).

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

#ChordRootMajor 3rdPerfect 5thMinor 7th♭9th

Five jazz chord progressions built around the Dominant 7♭9 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 Dominant 7♭9 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