2601/2600, the sextantonisma, is an unnoticeable 17-limit (also 2.3.5.13.17-subgroup) superparticular comma measuring about 0.666 cents. It may be properly described as the septendecimal sixth-tones comma, since it is the difference between 51/50 and 52/51, the two 17-limit sixth-tones. It also represents the little gap between 18/13 and a stack of two 20/17's.

Interval information
Ratio 2601/2600
Factorization 2-3 × 32 × 5-2 × 13-1 × 172
Monzo [-3 2 -2 0 0 -1 2
Size in cents 0.6657312¢
Name sextantonisma
Color name 17oo3ugg2, sosothugugu 2nd,
Sosothugugu comma
FJS name [math]\displaystyle{ \text{d2}^{17,17}_{5,5,13} }[/math]
Special properties square superparticular,
reduced
Tenney norm (log2 nd) 22.6891
Weil norm (log2 max(n, d)) 22.6897
Wilson norm (sopfr(nd)) 69
Comma size unnoticeable
S-expression S51
Open this interval in xen-calc

Commatic relations

In terms of commas, it is the difference between the following pairs:

* relation within the 2.3.5.13.17 subgroup

Temperaments

Tempering out this comma in the 17-limit results in the rank-6 sextantonismic temperament, or in the 2.3.5.13.17 subgroup, the rank-4 sextantonic temperament. In either case 26/25 is split into two equal parts, each representing 51/50~52/51, and sextantonismic chords are enabled.

If 140625/140608 is also added to the comma list, the sixth-tone above becomes literally a sixth of 9/8 and is tuned exactly middle of 51/50 and 52/51. This temperament, however, strongly suggests also tempering out 9801/9800 and/or 12376/12375 since 2601/2600 = (9801/9800)⋅(12376/12375)2(140625/140608).

Sextantonic

Subgroup: 2.3.5.13.17

Subgroup-val mapping[1 0 0 2 1], 0 1 0 0 -1], 0 0 0 0 1], 0 0 0 2 1]]

mapping generators: ~2, ~3, ~5, ~51/20

Optimal tunings:

  • WE: ~2 = 1200.0165 ¢, ~3/2 = 701.9109 ¢, ~5/4 = 386.3400 ¢, ~51/40 = 420.2767 ¢
  • CWE: ~2 = 1200.0000 ¢, ~3/2 = 701.9128 ¢, ~5/4 = 386.3554 ¢, ~51/40 = 420.2871 ¢

Optimal ET sequence22f, 26, 31, 34, 72, 106, 137, 171, 183, 217, 277, 354, 388, 460, 494, 677, 814, 848, 3609g, 4069g, 4457g, 4917gg

Badness (Sintel): 0.0654

Sextantonismic

Subgroup: 2.3.5.7.11.13.17

Mapping:

[⟨ 1 0 0 0 0 1 2 ],
0 1 0 0 0 0 -1 ],
0 0 1 0 0 0 1 ],
0 0 0 1 0 0 0 ],
0 0 0 0 1 0 0 ],
0 0 0 0 0 2 1 ]]
mapping generators: ~2, ~3, ~5, ~7, ~11, ~51/20

Optimal tunings:

  • WE: ~2 = 1200.0165 ¢, ~3/2 = 701.9109 ¢, ~5/4 = 386.3400 ¢, ~7/4 = 968.7969 ¢, ~11/8 = 551.2685 ¢, ~51/40 = 420.2767 ¢
  • CWE: ~2 = 1200.0000 ¢, ~3/2 = 701.9128 ¢, ~5/4 = 386.3554 ¢, ~7/4 = 968.8019 ¢, ~11/8 = 551.2883 ¢, ~51/40 = 420.2871 ¢

Optimal ET sequence17cg, 22f, 26, 29g, 31, 38df, 43, 46, 60e, 65d, 68, 72, 103, 111, 140, 171, 183, 217, 243e, 282, 311, 354, 400, 422, 460, 494, 742, 814, 954, 1236, 1696, 2190g, 4069g*

* optimal patent val: 2932

Badness (Sintel): 0.689

Etymology

The sextantonisma was named by Flora Canou in 2023. It is a contraction of sixth-tones comma into a single word consisting of Latin sextans ("sixth") and tonus ("tone"). This comma was chosen as the sixth-tones comma because the sixth-tones it separates lie in the middle of the harmonic series segment of sixth-tones, 48::54.

See also