Chords and scales
Over every chord you play a scale that contains its notes: the chord-scale relationship tells you which one. Here you will find the principle and, for every chord type, the possible scales from the most consonant to the most tense.
Over every chord you can play a scale: the scale contains the chord tones and fills the gaps between them. Choosing the right scale means choosing the colour of the melody.
The principle
A seventh chord has four notes: root, third, fifth and seventh. These are the "safe" notes, the ones that always sound good over that chord, especially on the strong beats.
Between one chord tone and the next there are gaps: the second, the fourth and the sixth. Filling them gives you a seven-note scale, and those extra notes (called the ninth, eleventh and thirteenth over the chord) are the tensions: they add colour.
The chord tones are fixed, the tensions are not: over a dominant chord the ninth can be natural, flat or sharp. That is why different scales can be played over the same chord, from the most consonant to the most tense.
Where the chord goes matters too
The scale does not depend only on the chord symbol, but on the chord's place in the progression. An m7 on the II of a major key takes Dorian, on the VI Aeolian, on the III Phrygian: they are the notes of the key, seen from different degrees.
Dominants are the most flexible. A dominant resolving to a major chord sounds good with Mixolydian; one resolving to a minor chord calls for the ♭9 and ♭13 (Phrygian dominant) or the altered scale, which contains every possible tension.
Avoid notes
Some scale notes clash when held over the chord: they are the notes a half step above a chord tone. The classic example is the fourth of the major scale over the maj7 chord (F over Cmaj7). They are not forbidden: they are used as passing notes, not as target notes. The Lydian, with its augmented fourth, exists precisely to get it out of the way.
Every chord and its scales
The scales are in order: the first is the most common, then the alternatives, up to the most tense. Tap a scale to see it on the keyboard.
Major triad: the major scale works; Lydian if you want to avoid the fourth; Mixolydian if the chord acts as a dominant.
Major chord with an augmented fifth, bright and unstable: Lydian augmented, the third mode of melodic minor.
Dominant chord: it takes more scales than any other. From the consonant Mixolydian and bebop, to Lydian dominant (♯11), Phrygian dominant (♭9 ♭13), up to the altered and diminished, the most tense. In the blues, also pentatonics and the blues scale.
Suspended dominant: the fourth replaces the third and the chord hangs in the air. Mixolydian; with Phrygian it becomes a sus♭9, with Aeolian a sus♭13.
Dominant with a flat ninth, typical of a dominant resolving to a minor chord. Phrygian dominant, Mixolydian ♭9, half-whole diminished or altered.
Dominant with a flat thirteenth. With a natural ninth, Mixolydian ♭6, Lydian minor or whole tone; if you also want the altered ninths, the altered scale.
Altered dominant: altered ninth and fifth. The altered scale contains them all (♭9, ♯9, ♯11, ♭13); alternatively its pentatonic or the diminished.
Dominant with an augmented fifth: the whole-tone scale, made only of whole steps, or the altered.
Minor with a major sixth, a minor tonic chord: melodic minor or Dorian.
Minor with a major seventh, the sound of the minor tonic in film music and jazz: melodic or harmonic minor.
Half-diminished, the II of the minor II V I: Locrian. With a natural ninth it becomes Locrian ♯2, the sixth mode of melodic minor.
Diminished seventh: four notes a minor third apart. The whole-half diminished, which adds a note a whole step above each chord tone.
Frequently asked questions
- What is the chord-scale relationship?
- It is the way to choose the scale to play over a chord: the scale must contain the chord tones, and the other notes become its tensions (ninth, eleventh, thirteenth).
- Which scale do you play over a dominant seventh chord?
- Mixolydian is the simplest. If the dominant resolves to a minor chord, use Phrygian dominant or altered; for a modern sound, Lydian dominant; in the blues, also the pentatonic and the blues scale.
- Which scale do you play over a minor seventh chord?
- It depends on the degree: Dorian on the II of a major key (the most common in jazz), Aeolian on the VI, Phrygian on the III.
- What are avoid notes?
- Scale notes that clash when held over the chord, because they sit a half step above a chord tone, like the fourth of the major scale over a maj7 chord. They are used as passing notes, not as target notes.
From the circle to chord progressions
In the MEG app you create exercises on II V I, blues and turnarounds through every key, by fifths as in the circle, with bass, piano and drum accompaniment. Meanwhile, try the generator in the key you chose.