Octatonic scale scale" . The twelve tones of the chromatic scale are covered by three disjoint diminished seventh chords. The notes from two such seventh-chords combination form an octatonic collection. Because there are three ways to select two from three, there are three octatonic scales in the twelve-tone system. Each octatonic scale has exactly two modes: the first begins its ascent with a whole step, while the second begins its ascent with a half step (semitone). These modes are sometimes referred to as the "whole step/half-step diminished scale" and the "half-step/whole step diminished scale", respectively. Each of the three distinct scales can
Heptatonic scale Heptatonic scale A heptatonic scale is a musical scale that has seven pitches per octave. Examples include the "major scale" or "minor scale"; e.g., in C major: C D E F G A B C—and in the relative minor, A minor, natural minor: A B C D E F G A; the "melodic minor scale", A B C D E FGA ascending, A G F E D C B A descending; the "harmonic minor scale", A B C D E F GA; and a scale variously known as the "Byzantine", and "Hungarian", scale, C D E F G A B