36edo: Difference between revisions

BudjarnLambeth (talk | contribs)
BudjarnLambeth (talk | contribs)
Octave stretch or compression: Moved text before tables
 
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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.  
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)}}
Line 1,018: Line 1,018:
What follows is a comparison of stretched- and compressed-octave 36edo tunings.
What follows is a comparison of stretched- and compressed-octave 36edo tunings.


 
; [[21edf]]  
; [[21edf]]
* Step size: 33.426{{c}}, octave size: 1203.351{{c}}
* Step size: 33.426{{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.
* Octave size: 1203.3{{c}}
{{Harmonics in equal|21|3|2|columns=11|collapsed=true}}
{{Harmonics in equal|21|3|2|columns=12|collapsed=true}}
{{Harmonics in equal|21|3|2|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 21edf (continued)}}
{{Harmonics in equal|21|3|2|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 21edf (continued)}}
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 primes up to 11 within ''12.0{{c}}''. The tuning 21edf does this.


; [[57edt]]
; [[57edt]]
* Step size: 33.368{{c}}
* Step size: 33.368{{c}}, octave size: 1201.235{{c}}
* Octave size: 1201.2{{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=12|collapsed=true}}
{{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)}}
{{Harmonics in equal|57|3|1|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 57edt (continued)}}


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 primes up to 11 within ''16.6{{c}}''. Five almost-identical tunings do this: 57edt, [[101ed7]], [[zpi|155zpi]], and the [[TE]] and [[WE]] 2.3.7.13 subgroup WE tunings of 36edo.
; 36edo
 
* Step size: 33.333{{c}}, octave size: 1200.000{{c}}  
 
Pure-octaves 36edo approximates all harmonics up to 16 within 15.3{{c}}.
; Pure-octaves 36edo
{{Harmonics in equal|36|2|1|intervals=integer|columns=11|collapsed=true}}
* Step size: 33.333{{c}}
{{Harmonics in equal|36|2|1|intervals=integer|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 36edo (continued)}}
* Octave size: 1200.0{{c}}  
{{Harmonics in equal|36|2|1|columns=12|collapsed=true}}
{{Harmonics in equal|36|2|1|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 57edt (continued)}}
 
Pure-octaves 36edo approximates all primes up to 11 within ''15.3{{c}}''.
 
 
; [[TE|11-limit TE 36edo]]
* Step size: 33.287{{c}}
* Octave size: 1198.3{{c}}
{{Harmonics in cet|33.287|columns=12|collapsed=true|title=Approximation of harmonics in 11lim WE-tuned 36edo}}
{{Harmonics in cet|33.287|columns=12|start=12|collapsed=true|title=Approximation of harmonics in 11lim WE-tuned 36edo (continued)}}
 
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 primes up to 11 within ''9.7{{c}}''. The 11- and 13-limit TE tunings of 36edo both do this, as do their respective WE tunings.


; [[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"
{| class="wikitable sortable center-all mw-collapsible mw-collapsed"
|+ Stretched/compressed tunings comparison table
|+ style="white-space: nowrap;" | Comparison of stretched and compressed tunings
|-
|-
! rowspan="2" | Tuning !! rowspan="2" | Step size<br>(cents) !! colspan="6" | Prime error (cents)  
! rowspan="2" | Tuning !! rowspan="2" | Octave size<br>(cents) !! colspan="6" | Prime error (cents)  
! rowspan="2" | Mapping of primes 2–13 (steps)
! rowspan="2" | Mapping of primes 2–13 (steps)
! rowspan="2" | Octave stretch
|-
|-
! 2 !! 3 !! 5 !! 7 !! 11  
! 2 !! 3 !! 5 !! 7 !! 11 !! 13
! 13
|-
|-
! 21edf
! 21edf
| 33.426
| 1203.351
| +3.3 || +3.3 || −12.0 || +7.2 || −6.5 || +5.1
| +3.3 || +3.3 || −12.0 || +7.2 || −6.5 || +5.1
| 36, 57, 83, 101, 124, 133
| 36, 57, 83, 101, 124, 133
| +0.275%
|-
|-
! 57edt
! 57edt
| 33.368 || +1.2 || 0.0 || +16.6 || +1.3 || −13.7 || −2.6
| 1201.235
| +1.2 || 0.0 || +16.6 || +1.3 || −13.7 || −2.6
| 36, 57, 84, 101, 124, 133
| 36, 57, 84, 101, 124, 133
| +0.001%
|-
|-
! 155zpi
! 155zpi
| 33.346
| 1200.587
| +0.6 || −1.0 || +15.1 || −0.5 || −16.0|| −5.0
| +0.6 || −1.0 || +15.1 || −0.5 || −16.0|| −5.0
| 36, 57, 83, 101, 124, 133
| 36, 57, 83, 101, 124, 133
| +0.0005%
|-
|-
! 36edo
! 36edo
| '''33.333'''
| '''1200.000'''
| '''0.0''' || '''−2.0''' || '''+13.7''' || '''−2.2''' || '''+15.3''' || '''−7.2'''
| '''0.0''' || '''−2.0''' || '''+13.7''' || '''−2.2''' || '''+15.3''' || '''−7.2'''
| '''36, 57, 84, 101, 125, 133'''
| '''36, 57, 84, 101, 125, 133'''
| '''0%'''
|-
|-
! 13-limit WE
! 13-limit TE
| 33.302
| 1198.929
| −1.1 || −3.7 || +11.1 || −5.3 || +11.4 || −11.4
| −1.1 || −3.7 || +11.2 || −5.2 || +11.6 || −11.1
| 36, 57, 84, 101, 125, 133
| 36, 57, 84, 101, 125, 133
| -0.0009%
|-
|-
! 11-limit WE
! 11-limit TE
| 33.286
| 1198.330
| −1.7 || −4.7 || +9.7 || −6.9 || +9.4 || −13.5
| −1.7 || −4.6 || +9.8 || −6.8 || +9.5 || −13.4
| 36, 57, 84, 101, 125, 133
| 36, 57, 84, 101, 125, 133
| -0.00142%
|}
|}