Lesson 36 · 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 a raised 9th on top — nicknamed the "Hendrix chord" — 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 a raised 9th on top — nicknamed the "Hendrix chord". 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 5 more semitones up from the 7th (15 semitones from the root — an octave plus a minor 3rd) — the ♯9th, a dominant 9th (Lesson 32) raised a semitone.
Example — E7♯9: start on E, count 4 semitones right to reach G♯, 3 more to reach B, 3 more to reach D, then 5 more to reach G (an octave and a minor 3rd above the root). E‑G♯‑B‑D‑G is the E7♯9 chord.
The ♯9th lands on the exact same key as the minor 3rd, an octave up — so a 7♯9 chord blends a major 3rd (down low) and what sounds like a minor 3rd (up high) at the same time, a clash of major and minor that gives it a bluesy, funky edge. That dual color is why guitarists and gospel keyboardists reach for it as a tonic vamp chord almost as often as they use it as a tense V chord resolving somewhere else.

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+5 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