231edo: Difference between revisions

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{{Infobox ET
{{Infobox ET}}
| Prime factorization = 3 × 7 × 11
{{ED intro}}
| Step size = 5.19481¢
| Fifth = 135\231 (701.30¢) (→ [[77edo|45\77]])
| Semitones = 21:18 (109.09¢ : 93.51¢)
| Consistency = 11
}}
The '''231 equal divisions of the octave''' ('''231edo'''), or the '''231(-tone) equal temperament''' ('''231tet''', '''231et''') when viewed from a [[regular temperament]] perspective, divides the [[octave]] into 231 [[equal]] parts of about 5.19 [[cent]]s each.


== Theory ==
== Theory ==
In the 5-limit, 231et tempers out the [[kleisma]], 15625/15552, and in the 7-limit [[1029/1024]], so that it [[support]]s the [[tritikleismic]] temperament, and in fact provides the [[optimal patent val]]. In the 11-limit it tempers out [[385/384]], [[441/440]] and [[4000/3993]], leading to 11-limit tritikleismic for which it also gives the optimal patent val.
In the 5-limit, 231et [[tempering out|tempers out]] the [[kleisma]], 15625/15552, and in the 7-limit [[1029/1024]], so that it [[support]]s the [[tritikleismic]] temperament, and in fact provides the [[optimal patent val]]. In the 11-limit it tempers out [[385/384]], [[441/440]] and [[4000/3993]], leading to 11-limit tritikleismic for which it also gives the optimal patent val.


231 years is the number of years in a 41 out of 231 leap week cycle, which corresponds to a 41 & 149 temperament tempering out 132055/131072, 166375/165888, and 2460375/2458624. This type of solar calendar leap rule scale may actually be of more use to harmony, since a 41 note subset mimics [[41edo]], a rather useful edo harmonically, and it preserves the simple commas mentioned above.
231 years is the number of years in a 41 out of 231 leap week cycle, which corresponds to a {{nowrap|41 & 149}} temperament tempering out 132055/131072, 166375/165888, and 2460375/2458624. This type of solar calendar leap rule scale may actually be of more use to harmony, since a 41 note subset mimics [[41edo]], a rather useful edo harmonically, and it preserves the simple commas mentioned above.  
 
Since the patent val mapping of fifth in 231edo is divisible by 9, it can be used for playing the [[Carlos Alpha]] scale.  


=== Odd harmonics ===
=== Odd harmonics ===
{{Harmonics in equal|231}}
{{Harmonics in equal|231}}
=== Subsets and supersets ===
231 = 3 × 7 × 11, with subset edos {{EDOs| 3, 7, 11, 21, 33, and 77 }}. Since it contains [[77edo]], it can be used for playing such a tuning of the [[Carlos Alpha]] scale.


== 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 stretch (¢)
! rowspan="2" | Optimal<br />8ve stretch (¢)
! colspan="2" | Tuning error
! colspan="2" | Tuning error
|-
|-
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| 2.3.5
| 2.3.5
| 15625/15552, {{monzo| -64 36 3 }}
| 15625/15552, {{monzo| -64 36 3 }}
| [{{val| 231 366 536 }}]
| {{mapping| 231 366 536 }}
| 0.410
| +0.410
| 0.334
| 0.334
| 6.43
| 6.43
Line 38: Line 34:
| 2.3.5.7
| 2.3.5.7
| 1029/1024, 15625/15552, 823543/820125
| 1029/1024, 15625/15552, 823543/820125
| [{{val| 231 366 536 648 }}]
| {{mapping| 231 366 536 648 }}
| 0.539
| +0.539
| 0.365
| 0.365
| 7.01
| 7.01
Line 45: Line 41:
| 2.3.5.7.11
| 2.3.5.7.11
| 385/384, 441/440, 4000/3993, 823543/820125
| 385/384, 441/440, 4000/3993, 823543/820125
| [{{val| 231 366 536 648 799 }}]
| {{mapping| 231 366 536 648 799 }}
| 0.469
| +0.469
| 0.354
| 0.354
| 6.81
| 6.81
Line 53: Line 49:
=== Rank-2 temperaments ===
=== Rank-2 temperaments ===
{| class="wikitable center-all left-5"
{| class="wikitable center-all left-5"
! Periods <br> per octave
|+ style="font-size: 105%;" | Table of rank-2 temperaments by generator
! Generator
|-
! Cents
! Periods<br />per 8ve
! Associated <br> ratio
! Generator*
! Cents*
! Associated<br />ratio*
! Temperaments
! Temperaments
|-
| 1
| 26\231
| 135.06
| 27/25
| [[Superlimmal]]
|-
|-
| 1
| 1
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|-
|-
| 3
| 3
| 61\231<br>(16\231)
| 61\231<br />(16\231)
| 316.88<br>(83.12)
| 316.88<br />(83.12)
| 6/5<br>(21/20)
| 6/5<br />(21/20)
| [[Tritikleismic]]
| [[Tritikleismic]]
|}
|}
<nowiki />* [[Normal lists|Octave-reduced form]], reduced to the first half-octave, and [[Normal lists|minimal form]] in parentheses if distinct
== Music ==
; [[Mercury Amalgam]]
* [https://www.youtube.com/watch?v=-bgUQ5BYnqM ''Sins of Stoicism''] (Demo Version, March 2022)


[[Category:Equal divisions of the octave]]
[[Category:Listen]]
[[Category:Tritikleismic]]
[[Category:Tritikleismic]]