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
Scale (music) pitches. A common scale in Eastern music is the pentatonic scale, which consists of five notes that span an octave. Some scales span part of an octave; Several such short scales are typically combined to form a scale spanning a full octave or more, and usually called with a third name of its own. The Middle Eastern music has around a dozen such basic short scales that are combined to form hundreds of full-octave spanning scales. Among these middle eastern scales Hejaz scale has one scale step spanning 14 intervals (of the middle eastern type found 53 in an octave)