Chord-scale relationships
Which scale fits each chord type, and why some notes need careful handling.
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Content under musical review. It may contain inaccuracies.
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Which scale fits each chord type, and why some notes need careful handling.
Advanced
A chord-scale relationship pairs each chord with a scale that contains its tones and fills the gaps with compatible tensions. It isn't a composing rule but a map: it tells you which notes sound stable, which add colour and which clash.
First the chord Dm7, then D Dorian, which contains it:
Now G7 and G Mixolydian:
The chord tones are the scale's skeleton. In Dorian, the root, minor third, fifth and minor seventh form Dm7; the rest are tensions:
String 6, Fret 3: G2 · 4 · Scale tone
Compare modes over the same root. Switch modes and listen for which characteristic degree appears:
Major-scale modes on D Melodic-minor modes on GA starting table, following Levine and common jazz practice:
| Chord | Common scale | Note to handle with care |
|---|---|---|
| maj7 | Ionian or Lydian | the 4 in Ionian |
| m7 | Dorian | none critical |
| 7 | Mixolydian | the 4 |
| m7b5 | Locrian or Locrian with natural 9 | the b2 in Locrian |
| 7 altered | altered | depends on context |
| dim7 | whole-half diminished | — |
An avoid note isn't forbidden. It's a note that, held over the chord, forms a minor ninth with a chord tone and sounds like a clash. For example, the fourth of Cmaj7, F, sits a half step above the third, E. In passing it sounds fine; as a long note, it rubs. Lydian raises that fourth and solves the problem.
Practising chord-scales doesn't mean running the scale up and down on every chord. Use it to know which notes you have, and combine it with target tones: chord tones on strong beats, scale tensions as passing notes or colour.
Many scales fit a dominant chord, and each implies certain tensions: Mixolydian gives 9 and 13; Lydian dominant, #11; half-whole diminished, b9, #9 and 13; altered, b9, #9, b5 and b13. Russell puts the Lydian scale at the centre of his system and ranks the others by their distance from it. Choosing a scale means choosing tensions, and they should match the accompanist's voicing.