36edo: Difference between revisions
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36edo is also notable for being the smallest multiple of 12edo to be [[distinctly consistent]] in the [[7-odd-limit]] (that is, all 7-odd-limit just intervals are represented by different steps). | 36edo is also notable for being the smallest multiple of 12edo to be [[distinctly consistent]] in the [[7-odd-limit]] (that is, all 7-odd-limit just intervals are represented by different steps). | ||
36edo has almost 50% relative error on harmonics 5/1 and 11/1. This means that whether one [[octave stretch|stretches]] or [[octave shrinking|compresses]] the octave, either way it will improve 36edo's approximations of [[JI]], but in opposite directions, as long as it is done by the right amount, as discussed in more detail in [[36edo#Octave_stretch_or_compression|octave stretch or compression]]. | |||
{{Harmonics in equal|36|intervals=odd|prec=2|columns=14}} | {{Harmonics in equal|36|intervals=odd|prec=2|columns=14}} | ||
{{Harmonics in equal|36|intervals=odd|columns=14|prec=2|start=15|collapsed=true|title=Approximation of odd harmonics in 36edo (continued)}} | {{Harmonics in equal|36|intervals=odd|columns=14|prec=2|start=15|collapsed=true|title=Approximation of odd harmonics in 36edo (continued)}} | ||
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=== Additional properties === | === Additional properties === | ||
36edo | 36edo offers a good approximation to the [[acoustic phi|acoustic golden ratio]], as 25\36. [[Heinz Bohlen]] proposed 36edo as a suitable temperament for approximating his 833-cents scale. The 13th harmonic (octave reduced) is so closely mapped on [[acoustic phi]] that 36edo could be treated as a 2.3.7.ϕ.17 temperament. | ||
Thanks to its sevenths, 36edo is an ideal tuning for its size for [[metallic harmony]]. | Thanks to its sevenths, 36edo is an ideal tuning for its size for [[metallic harmony]]. | ||
=== Subsets and supersets === | === Subsets and supersets === | ||
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|} | |} | ||
<nowiki/>* [[Normal lists|Octave-reduced form]], reduced to the first half-octave, and [[Normal lists|minimal form]] in parentheses if distinct | <nowiki/>* [[Normal lists|Octave-reduced form]], reduced to the first half-octave, and [[Normal lists|minimal form]] in parentheses if distinct | ||
== Octave stretch or compression == | |||
What follows is a comparison of stretched- and compressed-octave 36edo tunings. | |||
; [[21edf]] | |||
* Step size: 33.426{{c}}, octave size: 1203.351{{c}} | |||
Stretching the octave of 36edo by a little over 3{{c}} results in improved primes 5, 11, and 13, but worse primes 2, 3, and 7. This approximates all harmonics up to 16 within 13.4{{c}}. The tuning 21edf does this. | |||
{{Harmonics in equal|21|3|2|columns=11|collapsed=true}} | |||
{{Harmonics in equal|21|3|2|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 21edf (continued)}} | |||
; [[57edt]] | |||
* Step size: 33.368{{c}}, octave size: 1201.235{{c}} | |||
If one intends to use both 36edo's vals for 5/1 at once, stretching the octave of 36edo by about 1{{c}} optimises 36edo for that dual-5 usage, while also making slight improvements to primes 3, 7, 11, and 13. This approximates all harmonics up to 16 within 16.6{{c}}. Several almost-identical tunings do this: 57edt, [[93ed6]], [[101ed7]], [[zpi|155zpi]], and the 2.3.7.13-subgroup [[TE]] and [[WE]] tunings of 36et. | |||
{{Harmonics in equal|57|3|1|columns=11|collapsed=true}} | |||
{{Harmonics in equal|57|3|1|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 57edt (continued)}} | |||
; 36edo | |||
* Step size: 33.333{{c}}, octave size: 1200.000{{c}} | |||
Pure-octaves 36edo approximates all harmonics up to 16 within 15.3{{c}}. | |||
{{Harmonics in equal|36|2|1|intervals=integer|columns=11|collapsed=true}} | |||
{{Harmonics in equal|36|2|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 36edo (continued)}} | |||
; [[TE|36et, 13-limit TE tuning]] | |||
* Step size: 33.304{{c}}, octave size: 1198.929{{c}} | |||
Compressing the octave of 36edo by about 2{{c}} results in much improved primes 5 and 11, but much worse primes 7 and 13. This approximates all harmonics up to 16 within 11.6{{c}}. The 11- and 13-limit TE tunings of 36et both do this, as do their respective WE tunings. | |||
{{Harmonics in cet|33.303596|columns=11|collapsed=true|title=Approximation of harmonics in 13-limit TE tuning of 36et}} | |||
{{Harmonics in cet|33.303596|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 13-limit TE tuning of 36et (continued)}} | |||
{| class="wikitable sortable center-all mw-collapsible mw-collapsed" | |||
|+ style="white-space: nowrap;" | Comparison of stretched and compressed tunings | |||
|- | |||
! rowspan="2" | Tuning !! rowspan="2" | Octave size<br>(cents) !! colspan="6" | Prime error (cents) | |||
! rowspan="2" | Mapping of primes 2–13 (steps) | |||
|- | |||
! 2 !! 3 !! 5 !! 7 !! 11 !! 13 | |||
|- | |||
! 21edf | |||
| 1203.351 | |||
| +3.3 || +3.3 || −12.0 || +7.2 || −6.5 || +5.1 | |||
| 36, 57, 83, 101, 124, 133 | |||
|- | |||
! 57edt | |||
| 1201.235 | |||
| +1.2 || 0.0 || +16.6 || +1.3 || −13.7 || −2.6 | |||
| 36, 57, 84, 101, 124, 133 | |||
|- | |||
! 155zpi | |||
| 1200.587 | |||
| +0.6 || −1.0 || +15.1 || −0.5 || −16.0|| −5.0 | |||
| 36, 57, 83, 101, 124, 133 | |||
|- | |||
! 36edo | |||
| '''1200.000''' | |||
| '''0.0''' || '''−2.0''' || '''+13.7''' || '''−2.2''' || '''+15.3''' || '''−7.2''' | |||
| '''36, 57, 84, 101, 125, 133''' | |||
|- | |||
! 13-limit TE | |||
| 1198.929 | |||
| −1.1 || −3.7 || +11.2 || −5.2 || +11.6 || −11.1 | |||
| 36, 57, 84, 101, 125, 133 | |||
|- | |||
! 11-limit TE | |||
| 1198.330 | |||
| −1.7 || −4.6 || +9.8 || −6.8 || +9.5 || −13.4 | |||
| 36, 57, 84, 101, 125, 133 | |||
|} | |||
== Scales == | == Scales == | ||
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'''Catler''' | '''Catler''' | ||
* [[Lost spirit]] (approximated from [[Meantone]] in [[31edo]]): '''9 6 2 4 7 2 6''' | * [[Lost spirit]]{{idio}} (approximated from [[Meantone]] in [[31edo]]): '''9 6 2 4 7 2 6''' | ||
'''Hedgehog''' | '''Hedgehog''' | ||
* [[Hedgehog]][14] MOS: '''3 2 3 2 3 2 3 3 2 3 2 3 2 3''' | * [[Hedgehog]][14] MOS: '''3 2 3 2 3 2 3 3 2 3 2 3 2 3''' | ||
* Palace (subset of Hedgehog[14]): '''5 5 5 6 5 5 5''' | * Palace{{idio}} (subset of Hedgehog[14]): '''5 5 5 6 5 5 5''' | ||
[[833 Cent Golden Scale (Bohlen)]]: '''3 4 4 3 4 4 3''' | [[833 Cent Golden Scale (Bohlen)]]: '''3 4 4 3 4 4 3''' |