Heptatonic scale are considered subsets of a twelve-pitch scale roughly analogous to the Western chromatic scale. The first and fifth melakarta tones, corresponding to the first and eighth chromatic tones, are invariable in inflection, and the fourth melakarta tone, corresponding to the sixth or seventh chromatic tone, is allowed one of two inflections only, a natural ("shuddah") position and a raised ("tivra") position. The second and third melakarta tones can be picked from the 4 chromatic tones (second through fifth), and similarly for the sixth and seventh. Thus the number of possible forms is equal to twice the square of the number
Hexatonic scale a symmetric scale consisting of a repeated pattern of two semitones followed by a major third now used for improvisation and may substitute for any mode of the jazz minor scale. The scale originated in Nicolas Slonimsky's book "Thesaurus of Scales and Melodic Patterns" through the, "equal division of one octave into two parts," creating a tritone, and the, "interpolation of two notes," adding two consequent semitones after the two resulting notes. The scale is the fifth mode of Messiaen's list Hexatonic scale In music and music theory, a hexatonic scale is a scale with six pitches or notes per