Jazz scale

A jazz scale is any musical scale used in jazz. Many "jazz scales" are common scales drawn from Western European classical music, including the diatonic, whole-tone, octatonic (or diminished), and the modes of the ascending melodic minor. All of these scales were commonly used by late nineteenth and early twentieth-century composers such as Rimsky-Korsakov, Debussy, Ravel and Stravinsky, often in ways that directly anticipate jazz practice. Some jazz scales, such as the bebop scales, add additional chromatic passing tones to the familiar diatonic scales.

One important feature of jazz is what theorists call "the principles of chord-scale compatibility": the idea that a sequence of chords will generate a sequence of compatible scales. In classical major-mode harmony, chords typically belong to the same scale. (For example, a ii-V-I progression in C major will typically use only the notes of the C diatonic collection.) In jazz, a four-chord progression may use four different scales, often as the result of chordal alterations. For instance, in C major, a jazz musician may alter the V chord G-B-D-F with a flattened fifth, producing G-B-D♭-F. An improviser might then choose a scale containing these four notes, such as G whole tone (G-A-B-C♯-D♯-F), G octatonic [or symmetric diminished] (G-A♭-B♭-B-C♯-D-E-F), or a mode of either D or A♭ melodic minor ascending (G-A-B-C♯-D-E-F or G-A♭-B♭-C♭-D♭-E♭-F respectively). In each case the scale contains the chord tones G-B-D♭-F and is said to be compatible with it. This notion of "chord scale compatibility" marks a fundamental difference between jazz harmony and traditional classical practice.