Schismic–Mercator equivalence continuum

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This is a list showing technical temperament data. For an explanation of what information is shown here, you may look at the technical data guide for regular temperaments.

The schismic–Mercator equivalence continuum is a continuum of 5-limit temperaments which equate a number of schismas (32805/32768) with Mercator's comma ([-84 53). This continuum is theoretically interesting in that the temperaments associated with its various commas are all 5-limit microtemperaments.

All temperaments in the continuum satisfy (32805/32768)n ~ [-84 53. Varying n results in different temperaments listed in the table below. It converges to schismic as n approaches infinity. If we allow non-integer and infinite n, the continuum describes the set of all 5-limit temperaments supported by 53edo (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 1.8503390493…, and temperaments having n near this value tend to be the most accurate ones.

For a similar but perhaps more intuitive and practical concept, see Syntonic–chromatic equivalence continuum.

Temperaments with integer n
n Temperament Comma
Ratio Monzo
0 Mercator (52 digits) [-84 53
1 Counterschismic (44 digits) [-69 45 -1
2 Monzismic (36 digits) [54 -37 2
3 Alphatricot (28 digits) [39 -29 3
4 Vulture (22 digits) [24 -21 4
5 Amity 1600000/1594323 [9 -13 5
6 Kleismic 15625/15552 [-6 -5 6
7 Orson 2109375/2097152 [-21 3 7
8 Demibuzzard (22 digits) [-36 11 8
9 Untriton (32 digits) [-51 19 9
Schismic 32805/32768 [-15 8 1

We may invert the continuum by setting m such that 1/m + 1/n = 1. This may be called the counterschismic–Mercator equivalence continuum, which is essentially the same thing. The just value of m is 2.17600… While the counterschisma is of comparable size as the schisma, it is way more complex, so this continuum does not contain as many useful temperaments at integer points.

Temperaments with integer m
m Temperament Comma
Ratio Monzo
0 Mercator (52 digits) [-84 53
1 Schismic 32805/32768 [-15 8 1
2 Monzismic (36 digits) [54 -37 2
Counterschismic (44 digits) [-69 45 -1
Temperaments with fractional n and m
Temperament n m Comma
53 & 3684 11/6 = 1.83 11/5 = 2.2 [-339 230 -11
53 & 4296 13/7 = 1.857142 13/6 = 2.16 [393 -267 13
Countritonic 9/2 = 4.5 9/7 = 1.285714 [33 -34 9
Quartonic 11/2 = 5.5 11/9 = 1.2 [3 -18 11
Maja 17/3 = 5.6 17/14 = 1.2142857 [-3 -23 17
Ditonic 13/2 = 6.5 13/11 = 1.18 [-27 -2 13

Counterschismic

Counterschismic is generated by a perfect fifth, like schismic, but the 5th harmonic is located at +45 fifths instead of schismic's -8. They unite at 53edo, of course. 730edo may be recommended as a tuning.

Subgroup: 2.3.5

Comma list: [-69 45 -1

Mapping[1 0 -69], 0 1 45]]

mapping generators: ~2, ~3

Optimal tunings:

  • WE: ~2 = 1200.0116 ¢, ~3/2 = 701.9243 ¢
error map: +0.012 -0.019 +0.001]
  • CWE: ~2 = 1200.0000 ¢, ~3/2 = 701.9177 ¢
error map: 0.000 -0.037 -0.017]

Optimal ET sequence53, 412, 465, 518, 571, 624, 677, 730, 2973, 3703, 4433, 5163, 11056, 16219b

Badness (Sintel): 2.14

Demibuzzard (5-limit)

For extensions, see Buzzardsmic clan #Demibuzzard.

Subgroup: 2.3.5

Comma list: 69198046875/68719476736

Mapping[1 -4 10], 0 8 -11]]

mapping generators: ~2, ~16384/10125

Optimal tunings:

  • WE: ~2 = 1200.0000 ¢, ~16384/10125 = 837.8342 ¢
error map: +0.222 -0.171 -0.267]
  • CWE: ~2 = 1200.0000 ¢, ~16384/10125 = 837.6794 ¢
error map: 0.000 -0.520 -0.787]

Optimal ET sequence10, 33, 43, 53, 202, 255, 308, 361, 414, 775, 1189bc

Badness (Sintel): 3.06

Countritonic

For extensions, see Hemifamity temperaments #Countriton, Ragismic microtemperaments #Ragitritonic, and Garischismic clan #Garitritonic.

Subgroup: 2.3.5

Comma list: [33 -34 9

Mapping[1 -3 -15], 0 9 34]]

mapping generators: ~2, ~20480000/14348907

Optimal tunings:

  • WE: ~2 = 1199.9228 ¢, ~20480000/14348907 = 611.3248 ¢
error map: -0.077 +0.200 -0.113]
  • CWE: ~2 = 1200.0000 ¢, ~20480000/14348907 = 611.3614 ¢
error map: 0.000 +0.297 -0.027]

Optimal ET sequence51c, 53, 263, 316, 369, 422, 475, 528, 2587b, 3115b, 3643b

Badness (Sintel): 6.00

53 & 3684

Subgroup: 2.3.5

Comma list: [-339 230 -11

Mapping[1 2 11], 0 -11 -230]]

mapping generators: ~2, ~10737418240/10460353203

Optimal tunings:

  • WE: ~2 = 1200.000272 ¢, ~10737418240/10460353203 = 45.276910 ¢
error map: +0.0003 -0.0005 +0.0000]
  • CWE: ~2 = 1200.000000 ¢, ~10737418240/10460353203 = 45.276898 ¢
error map: 0.0000 -0.0009 -0.0003]

Optimal ET sequence53, …, 3313, 3366, 3419, 3472, 3525, 3578, 3631, 3684, 7421, 11105, 25894, 36999

Badness (Sintel): 6.48

53 & 4296

Subgroup: 2.3.5

Comma list: [393 -267 13

Mapping[1 -7 -174], 0 13 267]]

mapping generators: ~2, ~[61 -41 2

Optimal tunings:

  • WE: ~2 = 1199.999891 ¢, ~[61 -41 2 = 792.458032 ¢
error map: -0.0001 +0.0002 -0.0000]
  • CWE: ~2 = 1200.000000 ¢, ~[61 -41 2 = 792.458104 ¢
error map: 0.0000 +0.0004 +0.0002]

Optimal ET sequence53, …, 3872, 3925, 3978, 4031, 4084, 4137, 4190, 4243, 4296, 34315, 38611, 42907, 47203, 51499, 55795, 60091, 64387, 68683

Badness (Sintel): 4.07