Melodic minor scale

In traditional classical theory the melodic minor scale has two forms, as noted


above, an ascending form and a descending form. Although each of these forms of


itself comprises seven pitches, together they comprise nine, which might seem to


call into question the scale’s status as a heptatonic scale. In certain twentieth-century


music, however, it became common systematically to use the ascending form for


both ascending and descending passages. Such a use has been notably ascribed to


the works of Bela Bartok and to bop and post-bop jazz practice. The traditional


descending form of the melodic minor scale is equivalent to the natural minor scale in


both pitch collection (which is diatonic) and tonal center.