161edo: Difference between revisions

+infobox and improve intro
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inconsistencies in 25-odd-limit
 
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{{Infobox ET
{{Infobox ET}}
| Prime factorization = 7 × 23
{{ED intro}}
| Step size = 7.45324¢
| Fifth = 94\161 (700.62¢)
| Semitones = 14:13 (104.35¢ : 96.89)
| Consistency = 7
}}
The '''161 equal divisions of the octave''' ('''161edo'''), or the '''161(-tone) equal temperament''' ('''161tet''', '''161et''') when viewed from a [[regular temperament]] perspective, divides the [[octave]] into 161 [[equal]] parts of about 7.45 [[cent]]s each.


== Theory ==
== Theory ==
161edo tempers out the [[Würschmidt comma]], 393216/390625, in the 5-limit; [[3136/3125]], [[6144/6125]] and [[2401/2400]] in the 7-limit; [[243/242]], [[441/440]], [[540/539]] and 5632/5625 in the 11-limit; and [[1188/1183]], [[351/350]], [[847/845]], [[1575/1573]], [[1001/1000]] and [[1716/1715]] in the 13-limit. It serves as the [[optimal patent val]] for the [[mintone]] temperament in the 5-, 7-, 11- and 13-limits.
161edo has a [[perfect fifth]] slightly sharp of that of [[12edo]], such that it maps the [[Pythagorean comma]] to one step. It approximates many of the low primes fairly well; however, it is only consistent to the [[7-odd-limit]], due to [[10/9]] being mapped too sharply from prime [[5/1|5]] being sharp, while [[3/1|3]] is flat. Nonetheless it does well for its size in higher limits, with the inconsistent intervals in the [[23-odd-limit]] being 9/5, [[13/9]], [[23/13]], and their [[octave complement]]s, and additional inconsistencies in the [[25-odd-limit]] include [[25/18]], [[25/23]], and their octave complements. Prime [[29/1|29]] is also accurate, though harmonic [[27/1|27]] is mapped inconsistently flat, causing many of its intervals to be inconsistent. Additionally, the flatness of 27 causes [[28/27]] to be mapped wider than [[27/26]], meaning 161edo is at most [[diamond monotone]] in the 25-odd-limit.
 
As an equal temperament, 161et [[tempering out|tempers out]] the [[würschmidt comma]], 393216/390625, in the [[5-limit]]; [[3136/3125]], [[6144/6125]] and [[2401/2400]] in the [[7-limit]]; [[243/242]], [[441/440]], [[540/539]] and [[5632/5625]] in the [[11-limit]]; and [[351/350]], [[847/845]], [[1001/1000]], [[1188/1183]], [[1575/1573]] and [[1716/1715]] in the [[13-limit]]. It serves as the [[optimal patent val]] for the [[mintone]] temperament in the 5-, 7-, 11- and 13-limit.


=== Prime harmonics ===
=== Prime harmonics ===
161edo is notable as being low in [[29-limit]] relative error in the 100 to 200 range.
 
{{Harmonics in equal|161}}
{{Harmonics in equal|161}}
=== Subsets and supersets ===
Since 161 factors into 7 × 23, 161edo contains [[7edo]] and [[23edo]] as its subsets.
== Intervals ==
{{Interval table}}


== 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
|-
|-
Line 28: Line 31:
| 2.3
| 2.3
| {{monzo| -255 161 }}
| {{monzo| -255 161 }}
| [{{val| 161 255 }}]
| {{mapping| 161 255 }}
| +0.421
| +0.421
| 0.421
| 0.421
Line 35: Line 38:
| 2.3.5
| 2.3.5
| 393216/390625, {{monzo| -17 21 -7 }}
| 393216/390625, {{monzo| -17 21 -7 }}
| [{{val| 161 255 374 }}]
| {{mapping| 161 255 374 }}
| +0.099
| +0.099
| 0.570
| 0.570
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| 2.3.5.7
| 2.3.5.7
| 2401/2400, 3136/3125, 177147/175000
| 2401/2400, 3136/3125, 177147/175000
| [{{val| 161 255 374 452 }}]
| {{mapping| 161 255 374 452 }}
| +0.064
| +0.064
| 0.498
| 0.498
Line 49: Line 52:
| 2.3.5.7.11
| 2.3.5.7.11
| 243/242, 441/440, 3136/3125, 35937/35840
| 243/242, 441/440, 3136/3125, 35937/35840
| [{{val| 161 255 374 452 557 }}]
| {{mapping| 161 255 374 452 557 }}
| +0.037
| +0.037
| 0.448
| 0.448
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| 2.3.5.7.11.13
| 2.3.5.7.11.13
| 243/242, 351/350, 441/440, 847/845, 3136/3125
| 243/242, 351/350, 441/440, 847/845, 3136/3125
| [{{val| 161 255 374 452 557 596 }}]
| {{mapping| 161 255 374 452 557 596 }}
| -0.046
| −0.046
| 0.449
| 0.449
| 6.03
| 6.03
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| 2.3.5.7.11.13.17
| 2.3.5.7.11.13.17
| 243/242, 351/350, 441/440, 561/560, 847/845, 1089/1088
| 243/242, 351/350, 441/440, 561/560, 847/845, 1089/1088
| [{{val| 161 255 374 452 557 596 658 }}]
| {{mapping| 161 255 374 452 557 596 658 }}
| -0.018
| −0.018
| 0.422
| 0.422
| 5.66
| 5.66
Line 70: Line 73:
| 2.3.5.7.11.13.17.19
| 2.3.5.7.11.13.17.19
| 243/242, 324/323, 351/350, 441/440, 456/455, 495/494, 513/512
| 243/242, 324/323, 351/350, 441/440, 456/455, 495/494, 513/512
| [{{val| 161 255 374 452 557 596 658 684 }}]
| {{mapping| 161 255 374 452 557 596 658 684 }}
| -0.034
| −0.034
| 0.397
| 0.397
| 5.32
| 5.32
|}
|}
* 161et has a lower [[TE error|absolute error]] than any previous equal temperaments in the 19-limit, even though it is inconsistent in the corresponding odd limit. The same subgroup is only better tuned by [[183edo]].


=== 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 octave
|-
! Generator<br>(reduced)
! Periods<br />per 8ve
! Cents<br>(reduced)
! Generator*
! Associated<br>ratio
! Cents*
! Associated<br />ratio*
! Temperaments
! Temperaments
|-
|-
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| 16/15
| 16/15
| [[Vavoom]]
| [[Vavoom]]
|-
| 1
| 16\161
| 119.25
| 15/14
| [[Septidiasemi]]
|-
|-
| 1
| 1
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|-
|-
| 7
| 7
| 67\161<br>(2\161)
| 67\161<br />(2\161)
| 499.38<br>(14.91)
| 499.38<br />(14.91)
| 4/3<br>(81/80)
| 4/3<br />(81/80)
| [[Absurdity]]
| [[Absurdity]]
|}
|}
<nowiki />* [[Normal forms #Equave-reduced-generator form|Octave-reduced form]], reduced to the first half-octave, and [[normal forms #Minimal-generator form|minimal form]] in parentheses if distinct


[[Category:Equal divisions of the octave]]
[[Category:Mintone]]
[[Category:Mintone]]