15th-octave temperaments: Difference between revisions

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[[15edo]] has some close approximations including [[22/21]] to one step and [[77/64]] to four steps.
[[15edo]] has some close approximations including [[22/21]] to one step and [[77/64]] to four steps.


Temperaments discussed elsewhere include [[Cloudy clan #Pentadecal|pentadecal]].
Temperaments discussed elsewhere include [[blackwood family #Quindecic|quindecic]], [[keemic temperaments #Pentadecal|pentadecal]], [[Landscape microtemperaments #Slendscape|slendscape]], and [[Landscape microtemperaments #Phosphorus|phosphorus]].


== Pentadecoid ==
== Pentadecoid ==
In pentadecoid, the period (1\15) is given an interpretation of [[22/21]], and four of them represent the keenanismic minor third, [[77/64]] = ([[147/128]])⋅([[22/21]]). The temperament is named for an analog of its relating temperaments, [[decoid]] ({{nowrap| 130 & 140 }}) and [[quintosec family #Triacontoid|triacontoid]] ({{nowrap| 120 & 150 }}). Triacontoid is a weak extension of pentadecoid, as well as [[Landscape microtemperaments #Slendscape|slendscape]] ({{nowrap| 255 & 270 }}).
[[Subgroup]]: 2.3.7.11
[[Subgroup]]: 2.3.7.11


[[Comma list]]: 1362944/1361367, 1771561/1769472
[[Comma list]]: 1362944/1361367, 1771561/1769472


[[Mapping]]: {{mapping| 15 108 0 94 | 0 -2 1 -1 }}
{{Mapping|legend=1| 15 108 0 94 | 0 -2 1 -1 }}


: mapping generators: ~22/21, ~7
: mapping generators: ~22/21, ~7


[[Optimal tuning]] ([[CTE]]): ~22/21 = 80.0000, ~8/7 = 231.0071
[[Optimal tuning]] ([[CTE]]): ~22/21 = 80.0000, ~8/7 = 231.0071 (~1029/1024 = 8.9929)
 
{{Optimal ET sequence|legend=1| 120, 135, 660, 795, 930, 1065, 1200 }}
 
[[Badness]]: 0.025231
 
== Phosphorus ==
[[Subgroup]]: 2.3.5.7
 
[[Comma list]]: 250047/250000, {{monzo| 60 -96 1 32 }}
 
[[Mapping]]: {{mapping| 15 8 -4 -4 | 0 13 32 38 }}
 
: mapping generators: ~{{monzo| -21 34 4 -15 }}, ~210827008/199290375
 
[[Optimal tuning]] ([[CTE]]): ~{{monzo|-21 34 4 -15}} = 80.0000, ~28/27 = 62.9267
 
{{Optimal ET sequence|legend=1| 1125, 1335, 2460 }}
 
[[Badness]]: 0.381587
 
== Quindecic ==
Quindecic preserves the [[11-limit]] structure of [[15edo]], with an independent generator for [[13/1|harmonic 13]].
 
[[Subgroup]]: 2.3.5.7.11.13
 
[[Comma list]]: 28/27, 49/48, 55/54, 77/75
 
[[Mapping]]: {{mapping| 15 24 35 42 52 0 | 0 0 0 0 0 1 }}
 
: mapping generators: ~22/21, ~13
 
[[Optimal tuning]]s:
* [[CTE]]: ~22/21 = 80.000, ~13/8 = 840.528 (~40/39 = 39.472)
* [[POTE]]: ~22/21 = 80.000, ~13/8 = 852.924 (~40/39 = 27.076)


{{Optimal ET sequence|legend=1| 15, 30 }}
{{Optimal ET sequence|legend=1| 120, 135, 660, 795, 930, 1065, 1200, 1335, 2535e }}


[[Badness]]: 0.028944
[[Badness]] (Sintel): 0.951


{{Fractional-octave footer}}
{{Fractional-octave footer}}

Latest revision as of 10:57, 28 June 2026

15edo has some close approximations including 22/21 to one step and 77/64 to four steps.

Temperaments discussed elsewhere include quindecic, pentadecal, slendscape, and phosphorus.

Pentadecoid

In pentadecoid, the period (1\15) is given an interpretation of 22/21, and four of them represent the keenanismic minor third, 77/64 = (147/128)⋅(22/21). The temperament is named for an analog of its relating temperaments, decoid (130 & 140) and triacontoid (120 & 150). Triacontoid is a weak extension of pentadecoid, as well as slendscape (255 & 270).

Subgroup: 2.3.7.11

Comma list: 1362944/1361367, 1771561/1769472

Mapping[15 108 0 94], 0 -2 1 -1]]

mapping generators: ~22/21, ~7

Optimal tuning (CTE): ~22/21 = 80.0000, ~8/7 = 231.0071 (~1029/1024 = 8.9929)

Optimal ET sequence120, 135, 660, 795, 930, 1065, 1200, 1335, 2535e

Badness (Sintel): 0.951

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