Definition
In chromatic substitution a chord is preceded or replaced by a chord whose root is a half step above or below the target, or all the voices of a chord are shifted by a half step (chromatic planing). Approach chords are short-duration chords that "slide" onto the arrival chord; they are a central technique of jazz arranging (Berklee: Lowell and Pullig, Arranging for Large Jazz Ensemble).
Types of approach (target Cmaj7, melody E)
| Type | Approach chord | How it is built |
|---|---|---|
| Upper chromatic | Dbmaj7 (Db F Ab C) | same structure as the target, a half step above |
| Lower chromatic | Bmaj7 → Cmaj7 | same structure, a half step below |
| Dominant | G7 → Cmaj7 | V7 of the target |
| Tritone dominant | Db7 → Cmaj7 | subV7 |
| Diatonic | Dm7 → Cmaj7 (Em7 for approach from above) | nearby diatonic chord |
| Diminished | B°7 → Cmaj7 (or C#°7 → Dm7) | diminished seventh a half step below |
In horn arranging the principle is: the melody moves by step, and the inner voices copy the structure of the target transposed to the approach degree.
Side-slipping (sidestepping) in modal improvisation
Over a long vamp (e.g. D Dorian), the soloist or pianist moves up a half step (Eb Dorian) for a few bars and then returns: tension and release without changing the bass harmony. It is typical of Coltrane's quartet with McCoy Tyner and of 1960s modal jazz.
Chromatic ii–V
- Approach from above: Ebm7 – Ab7 → Dm7 – G7 → C. The ii–V a half step above prepares the real one.
- Approach from below: C#m7 – F#7 → Dm7 – G7 (less common, sounds very "outside").
- Double approach: Ebm7 Ab7 | Dm7 Db7 | Cmaj7.
Chromatic substitution of the bass (bass line reharm)
You first write a chromatic bass line and then choose on each note the chord that contains the melody:
Sustained melody G for 4 bars, bass C – B – Bb – A:
- C: Cmaj7 (G = 5)
- B: Em/B (G = b3 of Em)
- Bb: C7/Bb (G = 5) or Ebmaj7/Bb (G = 3)
- A: Am7 (G = b7)
One single sound in the melody, four different colors.
Chromatic planing
Repeating the same chord structure shifted by a half step: Dm9 – Ebm9 – Dm9 (funk), Cmaj7#11 – Dbmaj7#11 (fusion), voicings in fourths that slide. It is also the basis of house "chord stabs" transposed in parallel.
Rules for good use
- Short duration: the approach usually lasts an eighth note or a quarter note before the target.
- The melody must move by step toward the target note.
- Avoid two consecutive chromatic approaches in the same direction over more than 2–3 chords: the ear loses the key.
- In the mix, the approach can be quieter (velocity −10/−15) so that it sounds like an "ornament" and not a new chord.
Exercise for the producer
- Take a chord riff on a quarter-note grid: Cmaj7 – Am7 – Dm7 – G7.
- Before each chord, on the last eighth note of the preceding bar, insert the same chord a half step above (Dbmaj7 → Cmaj7, Bbm7 → Am7, Ebm7 → Dm7, Ab7 → G7).
- Quantize the slide to 1/8 with 55–58% swing: you'll get a "neo-soul" or big band effect depending on the sound.
Related topics
Extended tritone substitution, planing and constant structures, passing diminished chords, advanced reharmonization, neo-soul harmony.