VOICE LEADING AND PHRASE APPLICATION · 12 MIN SUGGESTED
Tritone Substitution on Jazz Guitar: D♭7 for G7
Explain D♭7 replacing G7 in C using its shared sounding tritone, correctly spelled degrees and chromatic bass.
Keep the tritone and change the dominant root · By Vincent Iannone · Updated
What is a tritone substitution?
A tritone substitution replaces a dominant seventh chord with the dominant seventh whose root is a tritone (three whole steps) away. In C, D♭7 can replace G7. It works because the two chords share the same tritone: G7’s third and seventh are B and F, and D♭7’s third and seventh are F and C♭, which sounds the same as B. The two guide tones swap roles: F changes from seventh to third, and B (written C♭) from third to seventh. The substitution also produces a chromatic bass line, D–D♭–C under Dm7–D♭7–Cmaj7. It is chosen for a dominant chord resolving to its tonic; it does not make any two chords interchangeable.
The idea
G7 contains B and F; D♭7 contains F and C♭. C♭4 and B3 share MIDI 59, while the third and seventh exchange functions. D3–D♭3–C3 supplies a chromatic bass. This substitution is chosen for a dominant-to-tonic arrival; it does not make every chord interchangeable.
Put it under your fingers
- Read B♭ and F♭ as the third and seventh of the worked G♭7.
- Identify the corresponding F/C♭ pair in D♭7, then restore G7 without moving the sounding upper tritone.
- Recognize the substitute in G and retrieve the C-major example.
A substitute dominant in F
In Gm7–G♭7–Fmaj7, G♭7’s third and seventh are B♭3 and F♭4. F♭4 sounds E4, the third of C7 and the seventh of Fmaj7. The upper line F4–F♭4–E4 moves down a semitone, then holds its sounding pitch.
Sounding notes: F4 → F♭4 → E4.
| # | Sounding note | Move from the previous note |
|---|---|---|
| 1 | F4 | Starting note |
| 2 | F♭4 | Down 1 semitone |
| 3 | E4 | Same pitch |
Make it yours
Play D–D♭–C in the bass while listening to the upper F/B tritone. Compare G7 and D♭7 with the same two sounding upper notes, naming their different degrees.
Keep the ideas connected.
- Guide-Tone Lines Through a Major ii–V–IConnect thirds and sevenths through a major ii–V–I, then change one tonic target deliberately.
- Minor ii–V–i on Jazz Guitar: m7♭5, 7♭9 and m6Hear iiø7–V7♭9 resolve into an explicitly named minor-sixth tonic and compare two nearby tonic targets.
- Dominant ♭9 Chords on Guitar: Resolving the Flat NineResolve a dominant lowered ninth to the tonic fifth, then compare the natural-ninth version with all other chord tones fixed.
- Jazz Guitar Phrasing Across Chord ChangesPlay one original line across named harmonic boundaries and retain its dominant-to-tonic resolution while changing one opening target.