Star and Nova

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Star

Star transversal

Star is an eight-note tempered scale, with something of the sound of the octatonic scale; however it is less regular and closer to just intonation. Star can be reached from various starting points, one of which is a 5-limit Fokker block which serves as a transversal for Star. The block in question is smithgw_star, 25/24-6/5-5/4-36/25-3/2-5/3-9/5-2/1, which consists of a chain of minor thirds 5/3-1-6/5-36/25 and that chain translated by 5/4, and which has three major and three minor triads.

Notes of Star

By tempering out 126/125, leading to 7-limit starling temperament we add the 7-limit intervals 8/7, 7/6, 7/5 and their inversions to the mix, and by tempering by 385/384 also, leading to 11-limit starling, the 11/8 interval also. There is no significant tuning advantage to 11-limit starling, a planar temperament, over the linear temperament valentine, so we may consider Star to be a scale of valentine. In valentine, with generator a tempered 21/20 of 78 cents, the notes of Star are -4, 0, 1, 4, 5, 8, 9 and 13 generators; in the ordering of the scale itself, that's 0, 1, 4, 5, 8, 9, -4, 13.

Since there are a finite number of 11-limit 8-note lesfip scales, we may consider the lesfip version of Star, star-lesfip, to be canonical. It can be reached from a variety of starting points. Lesfiping the 5-limit transversal in the range 14 to 17 cents of tolerance leads to Star; so does lesfiping the 46et version in the range from 9 to 17 cents or the 77et version in the range 6 to 16 cents. Another tuning for Star, not very different, is Star in 77et; 77 giving the optimal patent val for both 11-limit starling and valentine.

Chords of Star

Star has sixteen dyadic tetrads, of eleven different types, which are among those listed on the chords of valentine page. In terms of what's listed on that page, star has one otonal tetrad, given in the form 1-8/7-10/7-12/7 but better known as 1-5/4-3/2-7/4; one 1-6/5-3/2-12/7 utonal tetrad; and one each of the keenanismic tetrads 1-8/7-11/8-12/7, 1-6/5-11/8-12/7, 1-5/4-10/7-12/7 and 1-5/4-3/2-12/7. It also has two each of the starling tetrad, the traditional diminished seventh chord of meantone; the ambitonal just added sixth chord 1-6/5-3/2-9/5; and the three 9-limit starling tetrads 1-6/5-10/7-9/5, 1-5/4-10/7-9/5 and 1-5/4-3/2-9/5.

Transformations

Star has many permutations of its notes which send dyadic chords to other dyadic chords. We may use the standard cycle notation used with permutation groups to mean permutations of the pitch classes of Star lifted to permutations of star as a periodic scale. For instance, the cycle (01) interchanges note 0 with note 1, which also means exchanging note 8 for note 9, and in general Star[n] with Star[n+1] whenever n is divisible by 8. The four involutions (elements of order two) (01), (23), (45) and (67) all preserve the dyadic harmony character of the chords of Star, while changing the actual chords. Together, they generate an elementary abelian 2-group isomorphic to (Z/2Z)^4, which means fifteen nontrivial transformations. To these may be added involutions exchanging the adjacent even-odd pairs of the previous group, so that [0 2] for instance would mean, for n divisible by 8, Star[n] changes places with Star[n+2], and Star[n+1] with Star[n+3]. These involutions generate a group of infinite order, but on pitch classes we obtain a group of order 384. This is discussed from the point of view of graph theory here.

Nova

Nova transversal

Star has a twin, Nova, with very similar characteristics but without 11-limit harmonies. It too can be reached from various starting points. One is a 5-limit Fokker block transversal, smithgw_star2, 27/25-6/5-5/4-36/25-3/2-5/3-9/5-2/1, which consists of a chain of minor thirds 5/3-1-6/5-36/25 and that chain translated by 3/2 rather than 5/4, and which also has three major and three minor triads.

Notes of Nova

The transversal of Nova, when tempered by 126/125 (starling) temperament, leads to Nova. It can also be considered a scale of 7-limit valentine, for which both 77et and 185et will serve, the latter being the optimal patent val for both 7-limit starling and 7-limit valentine. In valentine, its notes in generator terms are -4, 0, 4, 5, 8, 9, 13 and 17, which in order of size are 0, 17, 4, 5, 8, 9, -4, 13.

The lesfip version of Nova, nova-lesfip, can be reached by lesfiping the transversal in the tolerance range 14 to 21 cents. It can also be reached from the 46et, 77et, or 185et tunings. The tolerance ranges are a little broader than those for Star since the lesfiping is done with respect to tbe 9-limit diamond; it also works from the 11-limit diamond, with narrower limits like those of Star, since then the 100/99 equivalencies must be avoided.

Chords of Nova

Like Star, Nova has sixteen dyadic tetrads, of eleven different types, which are among those listed on the chords of valentine page. These are one major and one minor tetrad, two starling tetrads (diminished seventh), three 1-6/5-3/2-9/5 added sixth tetrads, two each of 1-5/4-3/2-9/5 and 1-6/5-10/7-9/5 starling tetrads, one each of 1-5/4-10/7-9/5 and 1-5/4-7/5-9/5 starling tetrads; one 1-7/6-3/2-9/5 subminor tetrad, one 1-9/7-3/2-9/5 supermajor tetrad, and one 1-7/6-3/2-7/4 swiss tetrad.

Transformations

Nova has a 9-limit consonoance between the notes Nova[a] and Nova[b] if and only if Star has an 11-limit consonance between Star[a] and Star[b]. Because of that any piece in Star can be transposed note-for-note into a piece in Nova, and vice-versa. Moreover, everything said about Star in the section about transformations of Star is equally true of Nove, and the same holds for the graph-theoretic properties of Star discussed in the page on graph-theoretic properties of scales.

Music

Star 1-GrimaldiA+Bmod by Joel Grant Taylor

77et Star

Lesfip Star

both by Chris Vaisvil