Definition
Chord-scale theory associates each chord with a scale that contains its notes and its available tensions. Born from the ideas of George Russell (Lydian Chromatic Concept, 1953) and systematized at Berklee (Barrie Nettles and Richard Graf, The Chord Scale Theory & Jazz Harmony), it is used to choose notes for improvising, for writing lines, and for building voicings.
Chord tones, tensions, avoid notes
- Chord tones: 1, 3, 5, 7.
- Available tensions: 9, 11, 13 (and alterations) that do not destroy the function.
- Avoid note: a scale note that lies a half step above a chord tone (a b9 interval with respect to it) or that contradicts the function. It can be used as a passing tone, not as a long note or in a voicing.
Table in C major
| Chord | Scale | Available tensions | Avoid note |
|---|---|---|---|
| Cmaj7 | Ionian | 9 (D), 13 (A) | F (11): b9 above E |
| Dm7 | Dorian | 9 (E), 11 (G) | B (13) according to the Berklee tradition: it creates the tritone with F and recalls G7 |
| Em7 | Phrygian | 11 (A) | F (b9), C (b13) |
| Fmaj7 | Lydian | 9 (G), #11 (B), 13 (D) | none |
| G7 | Mixolydian | 9 (A), 13 (E) | C (11): b9 above B |
| Am7 | Aeolian | 9 (B), 11 (D) | F (b13): b9 above E |
| Bø7 | Locrian | 11 (E), b13 (G) | C (b9) — alternative: Locrian #2 with C# |
On Dm7 many musicians consider the 13 (B) characteristic of Dorian, especially in a modal context (So What): the rule depends on the function (ii of a ii–V or modal tonic).
Dominants: which scale?
| Context | Scale | Tensions |
|---|---|---|
| V7 toward major | Mixolydian | 9, 13 |
| V7 toward minor | Mixolydian b9 b13 (5th mode of harmonic minor) | b9, b13 |
| Altered V7 | Super Locrian (7th mode of melodic minor) | b9, #9, #11, b13 |
| V7 that does not resolve by fifth (bVII7, subV7, IV7 in the blues) | Lydian dominant | 9, #11, 13 |
| V7 with b9 and natural 13 | half-whole diminished | b9, #9, #11, 13 |
| V7#5 | whole-tone | 9, #11, b13 |
Minor chords
| Chord | Scale | Use |
|---|---|---|
| im7 tonic | Dorian or Aeolian | Dorian if modal, Aeolian in a natural minor context |
| im(maj7), im6 | melodic minor | "jazz" minor tonic |
| ivm7 | Dorian | minor subdominant |
How to really use it
- Analyze the progression (function of each chord).
- Choose the scale based on the function and the melody notes (the melody takes precedence).
- Connect the scales through common tones: G Mixolydian and C Ionian have the same seven notes (no added tension); G altered (G Ab Bb B Db Eb F) and C Ionian share only three notes (G, B, F): that is where the tension arises, and the other four resolve by half step.
- In voicings use chord tones + tensions, never a held avoid note.
Criticisms
Mark Levine (The Jazz Theory Book) and many teachers warn that thinking "one scale per chord" leads to scholastic improvisation: great improvisers think in lines and guide tones. Still, the theory remains an excellent tool for arrangers and producers.
Practical example for the producer
Pad on G7 before the chorus in C:
- If the chorus is major and bright: voicing G7(9,13) = F A B E.
- If it is melancholic: G7(b9,b13) = F Ab B Eb.
- If you want a "fusion" effect: Db7#11 (subV) with the Lydian dominant scale.
Avoid holding C (11) over G7 unless you are deliberately writing a G7sus4.
Related topics
Extensions and tensions, The modes of the major scale, jazz harmonic analysis, modal harmony for each mode, upper structure triads.