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== Theory == | == Theory == | ||
The equal temperament [[tempering out|tempers out]] the [[parakleisma]], {{monzo| 8 14 -13 }}, and the [[septendecima]], {{monzo| -52 -17 34 }}, in the 5-limit. In the 7-limit it tempers out | The equal temperament [[tempering out|tempers out]] the [[parakleisma]], {{monzo| 8 14 -13 }}, and the [[septendecima]], {{monzo| -52 -17 34 }}, in the [[5-limit]]. In the [[7-limit]] it tempers out 19683/19600 ([[cataharry comma]]), 16875/16807 ([[canopic comma]]), and 65625/65536 ([[horwell comma]]) so that it [[support]]s the [[mirkat]] temperament, and in fact provides the [[optimal patent val]]. It also gives the optimal patent val for mirkat in the [[11-limit]], tempering out [[540/539]], [[1375/1372]], [[3025/3024]] and [[8019/8000]]. In the [[13-limit]] it tempers out [[847/845]], [[625/624]], [[1575/1573]] and [[1716/1715]]. | ||
=== Prime harmonics === | === Prime harmonics === | ||
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=== Subsets and supersets === | === Subsets and supersets === | ||
Since 255 factors into {{ | Since 255 factors into {{nowrap| 3 × 5 × 17 }}, 255edo has subset edos {{EDOs| 3, 5, 15, 17, 51, and 85 }}. | ||
== Regular temperament properties == | == Regular temperament properties == | ||
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! Associated<br>ratio* | ! Associated<br>ratio* | ||
! Temperaments | ! Temperaments | ||
|- | |- | ||
| 1 | | 1 | ||
| Line 78: | Line 72: | ||
| 315.29 | | 315.29 | ||
| 6/5 | | 6/5 | ||
| [[ | | [[Counterpara]] | ||
|- | |- | ||
| 1 | | 1 | ||
| Line 87: | Line 81: | ||
|- | |- | ||
| 3 | | 3 | ||
| | | 39\255 | ||
| | | 183.53 | ||
| | | 10/9 | ||
| [[Mirkat]] (255f) | |||
|- | |||
| 3 | |||
| 3\255 | |||
| 14.12 | |||
| 126/125 | |||
| [[Mutt]] (7-limit) | | [[Mutt]] (7-limit) | ||
|- | |- | ||
| 5 | | 5 | ||
| | | 2\255 | ||
| | | 9.41 | ||
| | | 176/175 | ||
| [[Hemiquintile]] / hemiquint (255) / hemiquintilis (255f) | | [[Hemiquintile]] / hemiquint (255) / hemiquintilis (255f) | ||
|- | |- | ||
| 5 | | 5 | ||
| | | 4\255 | ||
| | | 18.82 | ||
| | | 81/80 | ||
| [[Quintile]] | | [[Quintile]] | ||
|- | |- | ||
| 17 | | 17 | ||
| | | 7\255 | ||
| | | 32.94 | ||
| | | 1990656/1953125 | ||
| [[Chlorine]] (5-limit) | | [[Chlorine]] (5-limit) | ||
|} | |} | ||
<nowiki/>* [[ | <nowiki/>* In [[normal forms #Minimal-generator form|minimal-generator form]] | ||
[[Category:Mirkat]] | [[Category:Mirkat]] | ||
Latest revision as of 08:42, 20 August 2026
| ← 254edo | 255edo | 256edo → |
255 equal divisions of the octave (abbreviated 255edo or 255ed2), also called 255-tone equal temperament (255tet) or 255 equal temperament (255et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 255 equal parts of about 4.71 ¢ each. Each step represents a frequency ratio of 21/255, or the 255th root of 2.
Theory
The equal temperament tempers out the parakleisma, [8 14 -13⟩, and the septendecima, [-52 -17 34⟩, in the 5-limit. In the 7-limit it tempers out 19683/19600 (cataharry comma), 16875/16807 (canopic comma), and 65625/65536 (horwell comma) so that it supports the mirkat temperament, and in fact provides the optimal patent val. It also gives the optimal patent val for mirkat in the 11-limit, tempering out 540/539, 1375/1372, 3025/3024 and 8019/8000. In the 13-limit it tempers out 847/845, 625/624, 1575/1573 and 1716/1715.
Prime harmonics
| Harmonic | 2 | 3 | 5 | 7 | 11 | 13 | 17 | 19 | 23 | 29 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Error | Absolute (¢) | +0.00 | -0.78 | -0.43 | +0.59 | -0.73 | +1.83 | -1.43 | -1.04 | +2.31 | +1.01 | -1.51 |
| Relative (%) | +0.0 | -16.5 | -9.2 | +12.4 | -15.5 | +38.8 | -30.3 | -22.2 | +49.2 | +21.5 | -32.0 | |
| Steps (reduced) |
255 (0) |
404 (149) |
592 (82) |
716 (206) |
882 (117) |
944 (179) |
1042 (22) |
1083 (63) |
1154 (134) |
1239 (219) |
1263 (243) | |
Subsets and supersets
Since 255 factors into 3 × 5 × 17, 255edo has subset edos 3, 5, 15, 17, 51, and 85.
Regular temperament properties
| Subgroup | Comma list | Mapping | Optimal 8ve stretch (¢) |
Tuning error | |
|---|---|---|---|---|---|
| Absolute (¢) | Relative (%) | ||||
| 2.3 | [-404 255⟩ | [⟨255 404]] | +0.246 | 0.246 | 5.22 |
| 2.3.5 | [8 14 -13⟩, [-36 11 8⟩ | [⟨255 404 592]] | +0.226 | 0.203 | 4.30 |
| 2.3.5.7 | 16875/16807, 19683/19600, 65625/65536 | [⟨255 404 592 716]] | +0.117 | 0.257 | 5.46 |
| 2.3.5.7.11 | 540/539, 1375/1372, 8019/8000, 65625/65536 | [⟨255 404 592 716 882]] | +0.136 | 0.233 | 4.95 |
Rank-2 temperaments
| Periods per 8ve |
Generator* | Cents* | Associated ratio* |
Temperaments |
|---|---|---|---|---|
| 1 | 52\255 | 244.71 | 15/13 | Subsemifourth (255) |
| 1 | 67\255 | 315.29 | 6/5 | Counterpara |
| 1 | 74\255 | 348.24 | 11/9 | Eris (255) |
| 3 | 39\255 | 183.53 | 10/9 | Mirkat (255f) |
| 3 | 3\255 | 14.12 | 126/125 | Mutt (7-limit) |
| 5 | 2\255 | 9.41 | 176/175 | Hemiquintile / hemiquint (255) / hemiquintilis (255f) |
| 5 | 4\255 | 18.82 | 81/80 | Quintile |
| 17 | 7\255 | 32.94 | 1990656/1953125 | Chlorine (5-limit) |