2601/2600
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 |
Sosothugugu comma
reduced
Commatic relations
In terms of commas, it is the difference between the following pairs:
- 289/288 and 325/324 *
- 561/560 and 715/714
- 833/832 and 1225/1224
- 1156/1155 and 2080/2079
- 1275/1274 and 2500/2499
- 1701/1700 and 4914/4913
- 2401/2400 and 31213/31212
- 2431/2430 and 37180/37179
* 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
- 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 sequence: 22f, 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
| [⟨ | 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
- 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 sequence: 17cg, 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*
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.