Dominants and their destination · Scales for improvising · Music theory
The scale of a dominant depends on where it goes. Toward a major chord, Mixolydian. Toward a minor one, it is best to add the notes of the destination,…
Dominants and their destination
The scale of a dominant depends on where it goes. Toward a major chord, Mixolydian. Toward a minor one, it is best to add the notes of the destination, which gives Mixolydian with ♭9 and ♭13, often called Phrygian dominant: the fifth mode of harmonic minor. Over E7 toward Am it is E, F, G♯, A, B, C, D.
The tritone substitute uses Lydian with a minor 7th: the fourth mode of melodic minor. In D♭7, that ♯11 is G, the very root of the chord it replaces. That is why it sounds so natural. Altered dominants use the altered scale, the seventh mode of that same melodic minor, which alters all that can be altered: ♭9, ♯9, ♯11, ♭13.