2L 5s

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Revision as of 23:24, 24 March 2021 by Inthar (talk | contribs) (reflect standardization of mavila to 7L 2s superdiatonic)
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2L 5s, pelogic, or antidiatonic refers to the structure of octave-equivalent MOS scales with generators ranging from 3\7 (3 degrees of 7edo = 514.29¢) to 1\2 (one degree of 2edo = 600¢). In the case of 7edo, L and s are the same size; in the case of 2edo, s becomes so small it disappears (and all that remains are the two equal L's).

While antidiatonic is closely associated with mavila temperament, not every 2L 5s scale an instance of "mavila", since some of them extend to 2L 7s scales (like the 2L 5s generated by 11edo's 6\11 = 656.5657¢), not 7L 2s mavila superdiatonic scales.

In terms of harmonic entropy, the most significant minimum is at Liese/Triton, in which the generator is about 7/5 and three of them make a 3/1.

generator in degrees of an edo generator in cents tetrachord L in cents s in cents L to s ratio comments
3\7 514.3 1 1 1 171.4 171.4 1.00
19\44 518.2 6 6 7 190.9 163.6 1.17
16\37 518.9 5 5 6 194.6 162.2 1.20
13\30 520.0 4 4 5 200.0 160.0 1.25 Mavila extends from here...
10\23 521.7 3 3 4 208.7 156.5 1.33
17\39 523.1 5 5 7 215.4 153.8 1.40
7\16 525.0 2 2 3 225.0 150.0 1.50 Mavila in Armodue

Optimum rank range (L/s=3/2)

526.3 2 2 pi 231.5 147.4 pi/2
18\41 526.8 5 5 8 234.1 146.3 1.60
1200*5/(13-phi) 1 1 phi 235.7 145.7 phi Golden mavila
29\66 527.3 8 8 13 236.4 145.5 1.625
11\25 528.0 3 3 5 240.0 144.0 1.67
529.1 1 1 √3 245.6 141.8 √3
15\34 529.4 4 4 7 247.1 141.2 1.75 ...to somewhere around here
4\9 533.3 1 1 2 266.7 133.3 2.00 Boundary of propriety (generators

smaller than this are proper)

13\29 537.9 3 3 7 289.7 124.1 2.33
9\20 540.0 2 2 5 300.0 120.0 2.50
541.4 1 1 phi+1 306.9 117.2 1 1 phi+1
14\31 541.9 3 3 8 309.7 116.1 2.66
542.5 1 1 e 321.55 115.0 e L/s = e
5\11 545.5 1 1 3 327.3 109.1 3.00 L/s = 3
546.8 1 1 pi 334.1 106.35 pi L/s = pi
11\24 550.0 2 2 7 350.0 100.0 3.50
6\13 553.8 1 1 4 369.2 92.3 4.00 Thuja is optimal around here

L/s = 4

7\15 560.0 1 1 5 400.0 80.0 5.00 ie. (11/8)^5 = 5/1
8\17 564.7 1 1 6 423.5 70.6 6.00
9\19 568.4 1 1 7 442.1 63.2 7.00 Liese/Triton is around here
1\2 600.0 0 0 1 600.0 0