Xenharmonic Wiki

612edo: Difference between revisions

← Older edit
VisualWikitext
Wikispaces>FREEZE
No edit summary
m →Theory: Fix missing word
 
(42 intermediate revisions by 11 users not shown)
Line 1: Line 1:
The ''612 equal division'' divides the octave into 612 equal parts of 1.961 cents each. It is a very strong [[5-limit|5-limit]] system, a fact noted by Bosanquet and Barbour. It tempers out the sasktel comma, |485 -306>, in the 3-limit and in the 5-limit |-52 -17 34>, the septendecima, |1 -27 18>, the ennealimma, |-53 10 16>, the kwazy comma, |54 -37 2>, the monzisma, |-107 47 14>, the fortune comma, and |161 -84 -12>, the atom. In the 7-limit it tempers out 2401/2400 and 4375/4374, so that it supports [[Ragismic_microtemperaments#Ennealimmal|ennealimmal temperament]], and in fact provides the [[Optimal_patent_val|optimal patent val]] for ennealimmal. The 7-limit val for 612 can be characterized as the ennealimmal commas plus the kwasy comma. In the 11-limit, it tempers out 3025/3024 and 9801/9800, so that 612 supports [[Ragismic_microtemperaments#Ennealimmal|hemiennealimmal temperament]].
{{Infobox ET}}
{{ED intro}}


The 612 division has been proposed as the logarithmic [[Interval_size_measure|interval size measure]] '''Skisma''' (or '''sk'''), since one step is nearly the same size as the schisma (32805/32768). Since 612 is divisible by 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, 68 and 72 divisions. A table of intervals approximated by 612 can be found under [[Table_of_612edo_intervals|Table of 612edo intervals]].
== Theory ==
[[Category:612edo]]
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]].
[[Category:edo]]
 
[[Category:ennealimmal]]
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]].
[[Category:hemiennealimmal]]
 
=== Prime harmonics ===
{{Harmonics in equal|612}}
 
== Regular temperament properties ==
{| class="wikitable center-4 center-5 center-6"
|-
! rowspan="2" | [[Subgroup]]
! rowspan="2" | [[Comma list]]
! rowspan="2" | [[Mapping]]
! rowspan="2" | Optimal<br>8ve stretch (¢)
! colspan="2" | Tuning error
|-
! [[TE error|Absolute]] (¢)
! [[TE simple badness|Relative]] (%)
|-
| 2.3.5
| {{monzo| 1 -27 18 }}, {{monzo| -53 10 16 }}
| {{Mapping| 612 970 1421 }}
| +0.0044
| 0.0089
| 0.46
|-
| 2.3.5.7
| 2401/2400, 4375/4374, {{monzo| -53 10 16 }}
| {{Mapping| 612 970 1421 1718 }}
| +0.0210
| 0.0297
| 1.52
|-
| 2.3.5.7.11
| 2401/2400, 3025/3024, 4375/4374, {{monzo| 21 -6 -7 -2 3 }}
| {{Mapping| 612 970 1421 1718 2117 }}
| +0.0363
| 0.0406
| 2.07
|-
| 2.3.5.7.11.13
| 2200/2197, 2401/2400, 3025/3024, 4096/4095, 4375/4374
| {{Mapping| 612 970 1421 1718 2117 2265 }}
| +0.0010
| 0.0871
| 4.44
|-
| 2.3.5.7.11.13.19
| 1331/1330, 1540/1539, 2200/2197, 2376/2375, 2926/2925, 4096/4095
| {{Mapping| 612 970 1421 1718 2117 2265 2600 }}
| −0.0168
| 0.0917
| 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.
* 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 ===
{| class="wikitable center-all left-5"
|+ style="font-size: 105%;" | Table of rank-2 temperaments by generator
|-
! Periods<br>per 8ve
! Generator*
! Cents*
! Associated<br>ratio*
! Temperaments
|-
| 1
| 113\612
| 221.57
| 8388608/7381125
| [[Fortune]]
|-
| 1
| 127\612
| 249.02
| {{monzo| -26 18 -1 }}
| [[Monzismic]]
|-
| 2
| 83\612
| 162.75
| 1125/1024
| [[Crazy]]
|-
| 4
| 194\612<br>(41\612)
| 380.39<br>(80.39)
| 81/65<br>(22/21)
| [[Quasithird]]
|-
| 9
| 133\612<br>(25\612)
| 315.69<br>(49.02)
| 6/5<br>(36/35)
| [[Ennealimmal]]
|-
| 12
| 124\612<br>(22\612)
| 243.137<br>(43.14)
| 3145728/2734375<br>(?)
| [[Magnesium]]
|-
| 12
| 254\612<br>(1\612)
| 498.04<br>(1.96)
| 4/3<br>(32805/32768)
| [[Atomic]]
|-
| 17
| 127\612<br>(17\612)
| 249.02<br>(33.33)
| {{monzo| -23 5 9 -2 }}<br>(100352/98415)
| [[Chlorine]]
|-
| 18
| 127\612<br>(9\612)
| 249.02<br>(17.65)
| 231/200<br>(99/98)
| [[Hemiennealimmal]] (11-limit)
|}
<nowiki/>* [[Normal lists|Octave-reduced form]], reduced to the first half-octave, and [[normal lists|minimal form]] in parentheses if distinct
 
== Music ==
; [[Eliora]]
* [https://www.youtube.com/watch?v=_DrkrgkiaAY ''Theme and Variations in Hemiennealimmal''] (2023)
 
== Notes ==
<references />
 
[[Category:Ennealimmal]]
[[Category:Hemiennealimmal]]
[[Category:Listen]]
Retrieved from "https://en.xen.wiki/w/612edo"