120/119
Interval information |
Suruyo comma
reduced
(Shannon, [math]\displaystyle{ \sqrt{nd} }[/math])
S18 × S19 × S20
120/119, the lynchisma is the 17-limit superparticular comma of about 14.49 cents. It is the difference between 20/17 and 7/6, 17/10 and 12/7, or 30/17 and 7/4. Tempering this comma allows you to assign 10:12:15:17 as the inverse of 4:5:6:7, a much simpler version of what would otherwise be 70:84:105:120. William Lynch calls this the minor tetrad, and so equating it with the inverse of the major tetrad is quite useful.
Temperaments
Tempering out this comma in the 17-limit leads to the rank-6 lynchismic temperament. In the 2.3.5.7.17 subgroup, tempering it out results in the rank-4 lynchic temperament.
Lynchismic
Subgroup: 2.3.5.7.11.13.17
[⟨ | 1 | 0 | 0 | 0 | 0 | 0 | 3 | ], |
⟨ | 0 | 1 | 0 | 0 | 0 | 0 | 1 | ], |
⟨ | 0 | 0 | 1 | 0 | 0 | 0 | 1 | ], |
⟨ | 0 | 0 | 0 | 1 | 0 | 0 | -1 | ], |
⟨ | 0 | 0 | 0 | 0 | 1 | 0 | 0 | ], |
⟨ | 0 | 0 | 0 | 0 | 0 | 1 | 0 | ]] |
- Mapping generators: ~2, ~3, ~5, ~7, ~11, ~13
- TE: ~2 = 1198.953, ~3 = 1901.078, ~5 = 2784.431, ~7 = 3371.578
- CTE: ~2 = 1200.000 (1\1), ~3/2 = 700.835, ~5/4 = 383.910, ~7/4 = 972.340
Lynchic
Subgroup: 2.3.5.7.17
Mapping: [⟨1 0 0 0 3], ⟨0 1 0 0 1], ⟨0 0 1 0 1], ⟨0 0 0 1 -1]]
- Mapping generators: ~2, ~3, ~5, ~7
Optimal tuning (CTE): ~2 = 1200.000 (1\1), ~3/2 = 700.835, ~5/4 = 383.910, ~7/4 = 972.340
Optimal ET sequence: 10, 12, 19, 22, 26, 31, 41, 53