Heptatonic scale
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A heptatonic scale is a musical scale with seven pitches per octave. Among the most famous of these are the diatonic scale, C D E F G A B C; the melodic minor scale, C D Eb F G A B C ascending, C Bb Ab G F Eb D C descending; the harmonic minor scale, C D Eb F G Ab B C; and a scale variously known as the Byzantine, Hungarian[1], gypsy[2], or Egyptian scale, C D Eb F# G Ab B C. South Indian (Carnatic music) classical theory postulates seventy-two melakarta, seven-tone scale types, whereas Hindustani classical music postulates twelve or ten (depending on the theorist) seven-tone scale types collectively called that.
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[edit] Diatonic scale
The term diatonic scale refers to a pitch collection and does not imply any particular tonal center or note of especial emphasis. It is in this respect different from the term major scale, which does imply a tonal center.
[edit] 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.
[edit] Harmonic minor scale
The harmonic minor scale is so called because in tonal music of the “common practice period” (from approximately 1600 to approximately 1900) chords or harmonies are more commonly derived from it than from either the natural minor scale or the melodic minor scale. The augmented second between its sixth degree and its raised (“leading tone”) seventh degree, usually traditionally considered undesirable, is easily avoided by distributing these pitches among voices. In the chord progression, D F Ab, B F G, C Eb G, (ii0, V7, i in C minor) for example, the Ab in the upper voice never ascends to B, and the B in the lower voice never descends to Ab.
[edit] Melakarta
The postulated number of melakarta derives from arithmetical calculation and not from Carnatic practice, which employs far fewer scale forms. Seven-pitch melakarta 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 seventh chromatic tones, are invariable in inflection, and the fourth melakarta tone, corresponding to the fifth or sixth chromatic tone, is allowed one of two inflections only, a natural (shuddah) position and a raised (tivra) position. Thus the number of possible forms is equal to twice the square of the number of ways a two-membered subset can be extracted from a four-membered set:
[edit] Thaat
Hindustani heptatonic theory additionally stipulates that the second, third, sixth and seventh degrees of heptatonic scale forms (septak) are also allowed only two inflections each, in this case, one natural position, and one lowered (komal) position. Arithmetically this produces 25, or thirty-two, possibilities, but Hindustani theory, in contradistinction to Carnatic theory, excludes scale forms not commonly used.
[edit] See also
[edit] References
- ^ The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell (London, 2001)
- ^ Ibid.
| Scales in music by number of pitches : | edit |
| pentatonic | hexatonic | heptatonic | octatonic | chromatic | |
