612edo: Difference between revisions
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{{Infobox ET}} | {{Infobox ET}} | ||
{{ED intro}} | |||
== Theory == | == Theory == | ||
612edo is a very strong [[5-limit]] system, a fact noted by {{w|Isaac Newton}}<ref>[https://emusicology.org/index.php/EMR/article/view/7647/6030 Muzzulini, Daniel. 2021. "Isaac Newton's Microtonal Approach to Just Intonation". ''Empirical Musicology Review'' 15 (3-4):223-48. https://doi.org/10.18061/emr.v15i3-4.7647.]</ref>, {{w|Robert Holford Macdowall Bosanquet|R. H. M. Bosanquet}}{{citation needed}} and {{w|James Murray Barbour}}{{citation needed}}. | 612edo is a very strong [[5-limit]] system, a fact noted by {{w|Isaac Newton}}<ref>[https://emusicology.org/index.php/EMR/article/view/7647/6030 Muzzulini, Daniel. 2021. "Isaac Newton's Microtonal Approach to Just Intonation". ''Empirical Musicology Review'' 15 (3-4):223-48. https://doi.org/10.18061/emr.v15i3-4.7647.]</ref>, {{w|Robert Holford Macdowall Bosanquet|R. H. M. Bosanquet}}{{citation needed}} and {{w|James Murray Barbour}}{{citation needed}}. As an equal temperament, it [[tempering out|tempers out]] the {{monzo| 485 -306 }} ([[sasktel comma]]) in the 3-limit, and in the 5-limit {{monzo| 1 -27 18 }} ([[ennealimma]]), {{monzo| -52 -17 34 }} ([[septendecima]]), {{monzo| -53 10 16 }} ([[kwazy comma]]), {{monzo| 54 -37 2 }} ([[monzisma]]), {{monzo| -107 47 14 }} (fortune comma), and {{monzo| 161 -84 -12 }} ([[atom]]). In the 7-limit it tempers out [[2401/2400]] and [[4375/4374]], so that it [[support]]s the [[ennealimmal]] temperament, and in fact provides the [[optimal patent val]] for ennealimmal. The 7-limit val for 612 can be characterized as the ennealimmal commas plus the kwazy comma. In the 11-limit, it tempers out [[3025/3024]] and [[9801/9800]], so that 612 supports the [[hemiennealimmal]] temperament. In the 13-limit, it tempers [[2200/2197]] and [[4096/4095]]. | ||
The 612edo has been proposed as the logarithmic [[interval size measure]] '''skisma''' (or '''sk'''), since one step is nearly the same size as the [[schisma]] (32805/32768), 1/12 of a [[Pythagorean comma]] or 1/11 of a [[syntonic comma]]. Since 612 is divisible by {{EDOs| 2, 3, 4, 6, 9, 12, 17, 18, 34, 36, 51, 68, 102, 153, 204 and 306 }}, it can readily express the step sizes of the 12, 17, 34, and 68 divisions. A table of intervals approximated by 612 can be found under [[Table of 612edo intervals]]. | The 612edo step has been proposed as the logarithmic [[interval size measure]] '''skisma''' (or '''sk'''), since one step is nearly the same size as the [[schisma]] (32805/32768), 1/12 of a [[Pythagorean comma]] or 1/11 of a [[syntonic comma]]. Since 612 is divisible by {{EDOs| 2, 3, 4, 6, 9, 12, 17, 18, 34, 36, 51, 68, 102, 153, 204 and 306 }}, it can readily express the step sizes of the 12, 17, 34, and 68 divisions. A table of intervals approximated by 612 can be found under [[Table of 612edo intervals]]. | ||
=== Prime harmonics === | === Prime harmonics === | ||
Line 12: | Line 12: | ||
== 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 23: | Line 24: | ||
| 2.3.5 | | 2.3.5 | ||
| {{monzo| 1 -27 18 }}, {{monzo| -53 10 16 }} | | {{monzo| 1 -27 18 }}, {{monzo| -53 10 16 }} | ||
| {{ | | {{Mapping| 612 970 1421 }} | ||
| +0.0044 | | +0.0044 | ||
| 0.0089 | | 0.0089 | ||
Line 30: | Line 31: | ||
| 2.3.5.7 | | 2.3.5.7 | ||
| 2401/2400, 4375/4374, {{monzo| -53 10 16 }} | | 2401/2400, 4375/4374, {{monzo| -53 10 16 }} | ||
| {{ | | {{Mapping| 612 970 1421 1718 }} | ||
| +0.0210 | | +0.0210 | ||
| 0.0297 | | 0.0297 | ||
Line 37: | Line 38: | ||
| 2.3.5.7.11 | | 2.3.5.7.11 | ||
| 2401/2400, 3025/3024, 4375/4374, {{monzo| 21 -6 -7 -2 3 }} | | 2401/2400, 3025/3024, 4375/4374, {{monzo| 21 -6 -7 -2 3 }} | ||
| {{ | | {{Mapping| 612 970 1421 1718 2117 }} | ||
| +0.0363 | | +0.0363 | ||
| 0.0406 | | 0.0406 | ||
Line 44: | Line 45: | ||
| 2.3.5.7.11.13 | | 2.3.5.7.11.13 | ||
| 2200/2197, 2401/2400, 3025/3024, 4096/4095, 4375/4374 | | 2200/2197, 2401/2400, 3025/3024, 4096/4095, 4375/4374 | ||
| {{ | | {{Mapping| 612 970 1421 1718 2117 2265 }} | ||
| +0.0010 | | +0.0010 | ||
| 0.0871 | | 0.0871 | ||
Line 51: | Line 52: | ||
| 2.3.5.7.11.13.19 | | 2.3.5.7.11.13.19 | ||
| 1331/1330, 1540/1539, 2200/2197, 2376/2375, 2926/2925, 4096/4095 | | 1331/1330, 1540/1539, 2200/2197, 2376/2375, 2926/2925, 4096/4095 | ||
| {{ | | {{Mapping| 612 970 1421 1718 2117 2265 2600 }} | ||
| | | −0.0168 | ||
| 0.0917 | | 0.0917 | ||
| 4.68 | | 4.68 | ||
|} | |} | ||
* 612et has a lower relative error than any previous equal temperaments in the 5-limit. Not until [[1171edo|1171]] do we find a better equal temperament in terms of either absolute error or relative error. | * 612et has a lower relative error than any previous equal temperaments in the 5-limit. Not until [[1171edo|1171]] do we find a better equal temperament in terms of either absolute error or relative error. | ||
* | * It also has a lower absolute error in the 7- and 11-limit than any previous equal temperaments, and is only bettered by [[935edo|935]] and [[836edo|836]], respectively. | ||
=== 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 | ! Periods<br>per 8ve | ||
! Generator* | ! Generator* | ||
! Cents* | ! Cents* | ||
! Associated<br> | ! Associated<br>ratio* | ||
! Temperaments | ! Temperaments | ||
|- | |- | ||
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| 162.75 | | 162.75 | ||
| 1125/1024 | | 1125/1024 | ||
| [[ | | [[Crazy]] | ||
|- | |- | ||
| 4 | | 4 | ||
Line 122: | Line 124: | ||
| [[Hemiennealimmal]] (11-limit) | | [[Hemiennealimmal]] (11-limit) | ||
|} | |} | ||
<nowiki>* | <nowiki/>* [[Normal lists|Octave-reduced form]], reduced to the first half-octave, and [[normal lists|minimal form]] in parentheses if distinct | ||
== Music == | == Music == | ||
Line 129: | Line 131: | ||
== Notes == | == Notes == | ||
<references /> | |||
[[Category:Ennealimmal]] | [[Category:Ennealimmal]] | ||
[[Category:Hemiennealimmal]] | [[Category:Hemiennealimmal]] | ||
[[Category:Listen]] | [[Category:Listen]] |