Superpyth

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Superpyth is a temperament of the archytas clan where ~3/2 is a generator, and the Archytas comma 64/63 is tempered out, so a stack of two generators octave-reduced represents 8/7 in addition to 9/8. Since 3/2 is a generator we can use the same standard chain-of-fifths notation that is also used for meantone and 12edo, with the understanding that sharps are sharper than flats (for example, A♯ is sharper than B♭) just like in Pythagorean tuning, in contrast to meantone where sharps are flatter than or equal to the corresponding flats. An interesting coincidence is that the plastic number has a value of ~486.822 cents, which, taken as a generator (~4/3) and assuming an octave period, constitutes a variety of superpyth.

Such a temperament without the 5th harmonic is also called archy. If intervals of 5 are desired, it is mapped to +9 generators through tempering out 245/243, so C-D♯ is 5/4. So superpyth is the "opposite" of septimal meantone in several different ways: Meantone (including 12edo) has 3/2 tuned flat so that the 5th harmonic's intervals are simple and the 7th harmonic's intervals are complex, while superpyth has 3/2 tuned sharp so that the 7th harmonic's intervals are simple while the 5th harmonic's intervals are complex.

If intervals of 11 are desired, the canonical way is to map 11/8 to +16 generators, or a doubly-augmented second (C–D𝄪), tempering out 100/99. Yet a simpler but reasonable way is to map it to −6 generators, or a diminished fifth (C–G♭), by tempering out 99/98. The latter is called supra, or suprapyth. The two mappings unite on 22edo.

If intervals of 13 are desired, 13/8 is mapped to +13 generators, or a doubly-augmented fourth (C–F𝄪), by tempering out 31213/31104.

Mos scales of superpyth have cardinalities of 5, 7, 12, 17, or 22.

For more technical data, see Archytas clan #Superpyth.

Interval chains

Archy (2.3.7)
1146.61 437.29 927.97 218.64 709.32 0 490.68 981.36 272.03 762.71 53.39
27/14 9/7 12/7 9/8~8/7 3/2 1/1 4/3 7/4~16/9 7/6 14/9 28/27
Full 7-limit superpyth
613.20 1102.91 392.62 882.33 172.04 661.75 1151.46 441.16 930.87 220.58 710.29 0 489.71 979.42 269.13 758.84 48.54 538.25 1027.96 317.67 807.38 97.09 586.80
10/7 15/8 5/4 5/3 10/9 27/14 9/7 12/7 9/8~8/7 3/2 1/1 4/3 7/4~16/9 7/6 14/9 28/27 9/5 6/5 8/5 16/15 7/5
Supra (2.3.7.11)
857.54 150.35 643.15 1135.96 428.77 921.58 214.38 707.19 0 492.81 985.62 278.42 771.23 64.04 556.85 1049.65 342.46
18/11 12/11 16/11 27/14 14/11~9/7 12/7 9/8~8/7 3/2 1/1 4/3 7/4~16/9 7/6 14/9~11/7 33/32~28/27 11/8 11/6 11/9
Full 11-limit suprapyth
604.44 1094.94 385.45 875.96 166.46 656.97 1147.47 437.98 928.48 218.99 709.49 0 490.51 981.01 271.52 762.02 52.53 543.03 1033.54 324.04 814.55 105.06 595.56
10/7 15/8 5/4 18/11~5/3 12/11~10/9 16/11 27/14 14/11~9/7 12/7 9/8~8/7 3/2 1/1 4/3 7/4~16/9 7/6 14/9~11/7 33/32~28/27 11/8 9/5~11/6 6/5~11/9 8/5 16/15 7/5

Scales

5-note MOS (2L 3s, proper)
  • Archy5 – archy in 472edo tuning
7-note MOS (5L 2s, improper)
  • Archy7 – archy in 472edo tuning
  • Supra7 – supra in 56edo tuning

In contrast to the meantone diatonic scale, the superpyth diatonic is improper.

12-note MOS (5L 7s, borderline improper)
  • Archy12 – archy in 472edo tuning
  • Supra12 – supra in 56edo tuning
  • 12-22a – superpyth in 22edo tuning

The boundary of propriety is 17edo.

Tunings

Prime-optimized tunings

2.3.7 Subgroup Prime-Optimized Tunings
Weight-skew\Order Euclidean
Tenney CTE: ~3/2 = 709.5948¢
Weil CWE: ~3/2 = 709.3901¢
Equilateral CEE: ~3/2 = 712.8606¢
Eigenmonzo basis (unchanged-interval basis): 2.49/3 (2/5-comma tuning)
Skewed-equilateral CSEE: ~3/2 = 711.9997¢
Eigenmonzo basis (unchanged-interval basis): 2.823543/243 (7/19-comma tuning)
Benedetti/Wilson CBE: ~3/2 = 707.7286¢
Eigenmonzo basis (unchanged-interval basis): 2.[0 -49 0 18 (18/85-comma tuning)
Skewed-Benedetti/Wilson CSBE: ~3/2 = 707.9869¢
Eigenmonzo basis (unchanged-interval basis): 2.[0 -63 25 (25/113-comma tuning)
7-limit Prime-Optimized Tunings
Weight-skew\Order Euclidean
Tenney CTE: ~3/2 = 709.5907¢
Weil CWE: ~3/2 = 710.1193¢
Equilateral CEE: ~3/2 = 709.7805¢
Eigenmonzo basis (unchanged-interval basis): 2.5859375/49
Skewed-equilateral CSEE: ~3/2 = 710.2428¢
Eigenmonzo basis (unchanged-interval basis): 2.[0 3 -37 18
Benedetti/Wilson CBE: ~3/2 = 709.4859¢
Eigenmonzo basis (unchanged-interval basis): 2.[0 -1225 -3969 450
Skewed-Benedetti/Wilson CSBE: ~3/2 = 710.0321¢
Eigenmonzo basis (unchanged-interval basis): 2.[0 665 -15771 5160

Tuning spectrum

Edo
Generator
Eigenmonzo
(Unchanged-interval)
Generator
(¢)
Comments
3/2 701.955 Pythagorean tuning
10\17 705.882 Lower bound of 7- and 9-odd-limit diamond monotone
81/56 706.499 1/6 comma
27/14 707.408 1/5 comma
23\39 707.692
9/7 708.771 1/4 comma, {1, 3, 7, 9} minimax
15/8 708.807
13\22 709.091
5/4 709.590 9-odd-limit minimax
49/27 709.745 2/7 comma
15/14 709.954
25/24 710.040
29\49 710.204
5/3 710.545
7/5 710.681 7-odd-limit minimax
7/6 711.043 1/3 comma, {1, 3, 7} minimax
16\27 711.111
21/20 711.553
9/5 711.772
19\32 712.500
49/48 712.861 2/5 comma, 2.3.7 subgroup CEE tuning
22\37 713.514
25\42 714.286
7/4 715.587 1/2 comma
3\5 720.000 Upper bound of 7- and 9-odd-limit diamond monotone
21/16 729.219 Full comma

Music

Lillian Hearne

Both in 22edo tuning

Joel Grant Taylor

All in superpyth[12] in 22edo tuning.

See also