Quasisuper

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Quasisuper; quasisupra
Subgroups 2.3.5.7, 2.3.5.7.11
Comma basis 64/63, 2430/2401 (7-limit);
64/63, 99/98, 121/120 (11-limit)
Reduced mapping ⟨1; 1 -13 -2 -6]
ET join 17c & 22
Generators (CWE) ~3/2 = 708.3 ¢
MOS scales 5L 2s, 5L 7s, 5L 12s, 17L 5s
Ploidacot monocot
Pergen (P8, P5)
Color name Sasaguti
Minimax error 9-odd-limit: 13.7 ¢;
11-limit 15-odd-limit: 14.9 ¢
Target scale size 9-odd-limit: 17 notes;
11-limit 15-odd-limit: 17 notes

Quasisuper is an alternative extension of the archy chain of fifths to superpyth. Like superpyth, it is a temperament generated by a perfect fifth, where stacking two of them reaches the interval of 8/7~9/8, tempering out 64/63. The difference is that this extension maps prime 5 to −13 generators, as a double-diminished fifth (C–G𝄫). This extension works in the range 17c-edo to 22-edo. In contrast, full 7-limit superpyth does not work in this range, as tunings with a flatter fifth than 22edo swap the sizes of 7/5 and 10/7. This extension may be preferred over superpyth due to having a softer diatonic scale, with a small step of around 60 cents compared to about 50 cents in regular 7-limit superpyth.

The best extension to the 11-limit, quasisupra, maps prime 11 to −6 generators as a diminished fifth (C–G♭), tempering out 99/98 as well as 121/120 and 540/539. Removing prime 5 from quasisupra results in a 2.3.7.11-subgroup restriction, called supra, which is notable for its simplicity. Finally, taking every other step of supra gives a 2.9.7.11-subgroup restriction, called machine.

For technical data see Archytas clan #Quasisuper and #Supra.

Interval chain

In the following tables, odd harmonics and subharmonics 1–11 are in bold.

Supra (2.3.7.11)
# Cents* Approximate ratios
0 0.0 1/1
1 707.5 3/2
2 215.0 8/7, 9/8
3 922.5 12/7
4 430.0 9/7, 14/11
5 1137.5 21/11, 27/14, 64/33
6 645.0 16/11
7 152.5 12/11

* In 2.3.7.11-subgroup CWE tuning,
octave reduced

Quasisuper/quasisupra
# Cents* Approximate ratios
0 0.0 1/1
1 708.3 3/2
2 216.6 8/7, 9/8
3 925.0 12/7
4 433.3 9/7, 14/11
5 1141.6 21/11, 27/14
6 649.9 16/11, 22/15
7 158.2 11/10, 12/11
8 866.6 18/11
9 374.9 27/22, 56/45
10 1083.2 28/15
11 591.5 7/5
12 99.8 16/15
13 808.2 8/5
14 316.5 6/5
15 1024.8 9/5
16 533.1 27/20
17 41.4 81/80, 56/55

* in 11-limit CWE tuning, octave reduced

Scales

Scala files

Tunings

7-limit norm-based tunings
Euclidean
Constrained Constrained & skewed Destretched
Tenney CTE: ~3/2 = 708.7690 ¢ CWE: ~3/2 = 708.3716 ¢ POTE: ~3/2 = 708.2385 ¢
11-limit norm-based tunings
Euclidean
Constrained Constrained & skewed Destretched
Tenney CTE: ~3/2 = 708.7131 ¢ CWE: ~3/2 = 708.3200 ¢ POTE: ~3/2 = 708.2046 ¢

Tuning spectrum

Edo
generator
Unchanged interval
(eigenmonzo)
*
Generator (¢) Comments
7\12 700.000 12cc val
3/2 701.955 Pythagorean tuning
21/11 703.893
11/7 704.377
10\17 705.882 17c val, lower bound of 7-, 9-, and 11-odd-limit diamond monotone
11/9 706.574
21/20 707.039
33\56 707.143 56cd val
11/6 707.234
7/5 707.501
23\39 707.692 39d val
9/5 707.840
15/14 708.056
11/8 708.114
36\61 708.197 61d val
5/3 708.260
5/4 708.745
9/7 708.771
13\22 709.091 Upper bound of 7-, 9-, and 11-odd-limit diamond monotone
11/10 709.286
15/8 709.311
15/11 710.508
7/6 711.043
16\27 711.111 27c val
7/4 715.587
3\5 720.000 5c val
21/16 729.219

* Besides the octave