Syntonic–31 equivalence continuum

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The syntonic-31 equivalence continuum is a continuum of 5-limit temperaments which equate a number of syntonic commas (81/80) with a 31-comma ([-49 31). This continuum is theoretically interesting in that these are all 5-limit temperaments supported by 31edo.

All temperaments in the continuum satisfy (81/80)n ~ [-49 31. Varying n results in different temperaments listed in the table below. It converges to meantone as n approaches infinity. If we allow non-integer and infinite n, the continuum describes the set of all 5-limit temperaments supported by 31edo (due to it being the unique equal temperament that tempers both commas and thus tempers all combinations of them). The just value of n is approximately 7.46781..., and temperaments having n near this value tend to be the most accurate ones.

Temperaments in the continuum
n Temperament Comma
Ratio Monzo
0 31 & 31c [-49 31
1 31 & 12c [-45 27 1
2 Quasimoha 2353579470675/2199023255552 [-41 23 2
3 Oncle 145282683375/137438953472 [-37 19 3
4 Sentinel 8968066875/8589934592 [-33 15 4
5 Tritonic 553584375/536870912 [-29 11 5
6 Ampersand 34171875/33554432 [-25 7 6
7 Orson 2109375/2097152 [-21 3 7
8 Würschmidt 393216/390625 [-17 -1 8
9 Valentine 1990656/1953125 [-13 -5 9
10 Myna 10077696/9765625 [9 9 -10
11 Nusecond 51018336/48828125 [5 13 -11
12 Cypress 258280326/244140625 [1 17 -12
13 Diesic 10460353203/9765625000 [-3 21 -13
14 31 & 13c 847288609443/781250000000 [-7 25 -14
Meantone 81/80 [-4 4 -1

Examples of temperaments with fractional values of n:

31 & 12c

In fifths notation, 5/4 is mapped to the quadruple-diminished fifth.

Comma list: [-45 27 1 = 38127987424935/35184372088832

POTE generator: ~4/3 = 503.0504

Mapping: [1 2 -9], 0 -1 27]]

Template:Val list

The temperament finder - 5-limit 31 & 12c

31 & 13c

Comma list: [-7 25 -14 = 847288609443/781250000000

POTE generator: 464.4231

Mapping: [1 7 12], 0 -14 -25]]

Template:Val list

The temperament finder - 5-limit 31 & 13c

31 & 70c

Comma list: [-54 18 11 = 18917016064453125/18014398509481984

POTE generator: 154.5972

Mapping: [1 3 0], 0 -11 18]]

Template:Val list

The temperament finder - 5-limit 31 & 70c