Scale quality

mixolydian ♭6

Mixolydian flat six is the fifth degree of melodic minor: a dominant scale with a flattened sixth, which darkens the major third's brightness and adds a melancholic, almost minor flavour to a major-quality scale. It is the sound of the 7♭13 chord and appears over dominant harmonies that want to resolve into a minor tonic, where the flat sixth anticipates the minor key. Jazz and film music use it for that bittersweet dominant colour. The scale still contains a major third and flat seventh, so it drives, but the flat sixth changes the light. Listen for the flat sixth pulling the phrase toward minor.