285edo: Difference between revisions
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{{Infobox ET}} | {{Infobox ET}} | ||
{{ | {{ED intro}} | ||
== Theory == | == Theory == | ||
285edo has a sharp tendency. | 285edo has a sharp tendency. The equal temperament [[tempering out|tempers out]] the [[misty comma]] and the [[enneadeca]] in the 5-limit; [[3136/3125]] and [[5120/5103]] in the 7-limit; [[3025/3024]] and [[3388/3375]] in the 11-limit; [[352/351]], [[676/675]], [[847/845]], [[1001/1000]], and [[2080/2079]] in the 13-limit. It supports the 13-limit [[hemimist]] temperament. | ||
=== Prime harmonics === | === Prime harmonics === | ||
{{Harmonics in equal|285}} | {{Harmonics in equal|285|intervals=prime}} | ||
=== Subsets and supersets === | === Subsets and supersets === | ||
Since 285 factors into | Since 285 factors into {{factorisation|285}}, 285edo has subset edos {{EDOs| 3, 5, 15, 19, 57, and 95 }}. | ||
== Regular temperament properties == | == Regular temperament properties == | ||
{| class="wikitable center-4 center-5 center-6" | {| class="wikitable center-4 center-5 center-6" | ||
|- | |||
! rowspan="2" | [[Subgroup]] | ! rowspan="2" | [[Subgroup]] | ||
! rowspan="2" | [[Comma list | ! rowspan="2" | [[Comma list]] | ||
! rowspan="2" | [[Mapping]] | ! rowspan="2" | [[Mapping]] | ||
! rowspan="2" | Optimal<br>8ve | ! rowspan="2" | Optimal<br />8ve stretch (¢) | ||
! colspan="2" | Tuning | ! colspan="2" | Tuning error | ||
|- | |- | ||
! [[TE error|Absolute]] (¢) | ! [[TE error|Absolute]] (¢) | ||
Line 24: | Line 25: | ||
| 2.3 | | 2.3 | ||
| {{monzo| 452 -285 }} | | {{monzo| 452 -285 }} | ||
| | | {{mapping| 285 452 }} | ||
| | | −0.3795 | ||
| 0.3794 | | 0.3794 | ||
| 9.01 | | 9.01 | ||
Line 31: | Line 32: | ||
| 2.3.5 | | 2.3.5 | ||
| 67108864/66430125, {{monzo| -14 -19 19 }} | | 67108864/66430125, {{monzo| -14 -19 19 }} | ||
| | | {{mapping| 285 452 662 }} | ||
| | | −0.4043 | ||
| 0.3117 | | 0.3117 | ||
| 7.41 | | 7.41 | ||
Line 38: | Line 39: | ||
| 2.3.5.7 | | 2.3.5.7 | ||
| 3136/3125, 5120/5103, 40353607/39858075 | | 3136/3125, 5120/5103, 40353607/39858075 | ||
| | | {{mapping| 285 452 662 800 }} | ||
| | | −0.2673 | ||
| 0.3596 | | 0.3596 | ||
| 8.54 | | 8.54 | ||
Line 45: | Line 46: | ||
| 2.3.5.7.11 | | 2.3.5.7.11 | ||
| 3025/3024, 3136/3125, 5120/5103, 12005/11979 | | 3025/3024, 3136/3125, 5120/5103, 12005/11979 | ||
| | | {{mapping| 285 452 662 800 986 }} | ||
| | | −0.2289 | ||
| 0.3307 | | 0.3307 | ||
| 7.85 | | 7.85 | ||
Line 52: | Line 53: | ||
| 2.3.5.7.11.13 | | 2.3.5.7.11.13 | ||
| 352/351, 676/675, 847/845, 3025/3024, 12005/11979 | | 352/351, 676/675, 847/845, 3025/3024, 12005/11979 | ||
| | | {{mapping| 285 452 662 800 986 1055 }} | ||
| | | −0.2618 | ||
| 0.3107 | | 0.3107 | ||
| 7.38 | | 7.38 | ||
Line 60: | Line 61: | ||
=== Rank-2 temperaments === | === Rank-2 temperaments === | ||
{| class="wikitable center-all left-5" | {| class="wikitable center-all left-5" | ||
|+Table of rank-2 temperaments by generator | |+ style="font-size: 105%;" | Table of rank-2 temperaments by generator | ||
! Periods<br>per 8ve | |- | ||
! Generator | ! Periods<br />per 8ve | ||
! Cents | ! Generator* | ||
! Associated<br> | ! Cents* | ||
! Associated<br />ratio* | |||
! Temperaments | ! Temperaments | ||
|- | |- | ||
Line 74: | Line 76: | ||
|- | |- | ||
| 3 | | 3 | ||
| 59\285<br>(36\285) | | 59\285<br />(36\285) | ||
| 248.42<br>(151.58) | | 248.42<br />(151.58) | ||
| 15/13<br>(12/11) | | 15/13<br />(12/11) | ||
| [[Hemimist]] | | [[Hemimist]] | ||
|- | |- | ||
| 3 | | 3 | ||
| 59\285<br>(23\285) | | 59\285<br />(23\285) | ||
| 496.84<br>(96.84) | | 496.84<br />(96.84) | ||
| 4/3<br>(256/243) | | 4/3<br />(256/243) | ||
| [[Misty]] | | [[Misty]] | ||
|- | |- | ||
| 19 | | 19 | ||
| 118\285<br>(2\285) | | 118\285<br />(2\285) | ||
| 496.84<br>(8.42) | | 496.84<br />(8.42) | ||
| 4/3<br>(15625/15552) | | 4/3<br />(15625/15552) | ||
| [[Enneadecal]] (5-limit) | | [[Enneadecal]] (5-limit) | ||
|} | |} | ||
<nowiki />* [[Normal lists|Octave-reduced form]], reduced to the first half-octave, and [[Normal lists|minimal form]] in parentheses if distinct |
Latest revision as of 06:28, 21 February 2025
← 284edo | 285edo | 286edo → |
285 equal divisions of the octave (abbreviated 285edo or 285ed2), also called 285-tone equal temperament (285tet) or 285 equal temperament (285et) when viewed under a regular temperament perspective, is the tuning system that divides the octave into 285 equal parts of about 4.21 ¢ each. Each step represents a frequency ratio of 21/285, or the 285th root of 2.
Theory
285edo has a sharp tendency. The equal temperament tempers out the misty comma and the enneadeca in the 5-limit; 3136/3125 and 5120/5103 in the 7-limit; 3025/3024 and 3388/3375 in the 11-limit; 352/351, 676/675, 847/845, 1001/1000, and 2080/2079 in the 13-limit. It supports the 13-limit hemimist temperament.
Prime harmonics
Harmonic | 2 | 3 | 5 | 7 | 11 | 13 | 17 | 19 | 23 | 29 | 31 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Error | Absolute (¢) | +0.00 | +1.20 | +1.05 | -0.40 | +0.26 | +1.58 | +0.31 | +1.43 | -0.91 | +2.00 | +0.23 |
Relative (%) | +0.0 | +28.6 | +25.0 | -9.6 | +6.2 | +37.5 | +7.3 | +34.1 | -21.5 | +47.5 | +5.4 | |
Steps (reduced) |
285 (0) |
452 (167) |
662 (92) |
800 (230) |
986 (131) |
1055 (200) |
1165 (25) |
1211 (71) |
1289 (149) |
1385 (245) |
1412 (272) |
Subsets and supersets
Since 285 factors into 3 × 5 × 19, 285edo has subset edos 3, 5, 15, 19, 57, and 95.
Regular temperament properties
Subgroup | Comma list | Mapping | Optimal 8ve stretch (¢) |
Tuning error | |
---|---|---|---|---|---|
Absolute (¢) | Relative (%) | ||||
2.3 | [452 -285⟩ | [⟨285 452]] | −0.3795 | 0.3794 | 9.01 |
2.3.5 | 67108864/66430125, [-14 -19 19⟩ | [⟨285 452 662]] | −0.4043 | 0.3117 | 7.41 |
2.3.5.7 | 3136/3125, 5120/5103, 40353607/39858075 | [⟨285 452 662 800]] | −0.2673 | 0.3596 | 8.54 |
2.3.5.7.11 | 3025/3024, 3136/3125, 5120/5103, 12005/11979 | [⟨285 452 662 800 986]] | −0.2289 | 0.3307 | 7.85 |
2.3.5.7.11.13 | 352/351, 676/675, 847/845, 3025/3024, 12005/11979 | [⟨285 452 662 800 986 1055]] | −0.2618 | 0.3107 | 7.38 |
Rank-2 temperaments
Periods per 8ve |
Generator* | Cents* | Associated ratio* |
Temperaments |
---|---|---|---|---|
1 | 109\285 | 458.95 | 125/96 | Majvam |
3 | 59\285 (36\285) |
248.42 (151.58) |
15/13 (12/11) |
Hemimist |
3 | 59\285 (23\285) |
496.84 (96.84) |
4/3 (256/243) |
Misty |
19 | 118\285 (2\285) |
496.84 (8.42) |
4/3 (15625/15552) |
Enneadecal (5-limit) |
* Octave-reduced form, reduced to the first half-octave, and minimal form in parentheses if distinct