Melodic Minor Scale

Melodic minor raises both the sixth and seventh degrees of natural minor when ascending, then uses the natural minor scale when descending. The classical reasoning: the augmented second in harmonic minor (between ♭6 and raised 7th) is difficult to sing, so melodic minor smooths it out by raising the 6th too. In jazz, only the ascending form is used — the same ascending notes in both directions — because the scale's modes are so harmonically rich.

Construction

Classical form:
A melodic minor ascending:  A B C D E F# G# A
A melodic minor descending: A G F E D C B A   (= natural minor)

Jazz melodic minor (same ascending both ways):
A B C D E F# G# A

Formula: 1  2  ♭3  4  5  6  7
= Major scale with a flatted 3rd only

The jazz melodic minor scale is essentially a major scale with a minor third. This hybrid quality — one foot in major, one in minor — gives it a distinctly ambiguous sound that jazz composers have mined extensively.

Key Scales

A melodic minor:  A B C D E F# G# A
D melodic minor:  D E F G A B C# D
G melodic minor:  G A B♭ C D E F# G
C melodic minor:  C D E♭ F G A B C

The Melodic Minor Modes

The modes of melodic minor are among the most important scales in modern jazz harmony:

Mode 1: Melodic minor      → over Im(maj7), m6 chords
Mode 2: Dorian ♭2          → dark minor sound with ♭2
Mode 3: Lydian augmented   → over maj7♯5 chords
Mode 4: Lydian dominant    → over IV7, tritone sub dominants (see its article)
Mode 5: Mixolydian ♭6      → over V7♭13 chords
Mode 6: Locrian #2         → over m7♭5 chords (better than regular Locrian)
Mode 7: Altered (Super Locrian) → over V7alt chords (see its article)

Modes 4 (Lydian dominant) and 7 (Altered) are the most commonly used in jazz. Mode 6 (Locrian #2) is the preferred sound over half-diminished chords — the natural 2nd avoids the harshest tension of regular Locrian.

Sound and Use

Melodic minor over a Im(maj7) chord — C minor with a major seventh (CmM7) — has a slightly unresolved, searching quality. It's a more sophisticated minor sound than Dorian or Aeolian, and it's used in jazz for that ambiguous major-minor quality. The Bossa Nova harmonic language draws heavily on melodic minor modes: the floating quality of "Corcovado" or "Triste" is partly melodic minor harmony.