User:BudjarnLambeth/Draft related tunings section

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Revision as of 11:08, 20 August 2025 by BudjarnLambeth (talk | contribs) (Going to begin cautiously rolling this out over the coming days)
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The guidelines

These are draft guidelines for what a standard "related tunings"-type section should look like on edo pages, using 36edo as an example.


Useful links for working on this
Which tunings should be listed for any given edo
  • The edo's pure-octaves tuning
  • 1 to 3 nearby edonoi (eg an edt, an edf, an ed5, an ed7, an ed4/3, anything like that)
  • 1 to 2 nearby ZPIs (or any other "infinite harmonics" optimised tuning other than ZPI)
  • 1 to 2 subgroup TE- or WE-optimal tunings, based on the best choice(s) of subgroup for the edo
  • 1 other equal tuning of any kind at all (optional)

Additional guidelines for selecting tunings:

  • In total, 3 to 8 tunings should be listed.
  • The selection of tunings should cover a range of meaningfully different tunings (eg with a range of different mappings).
Further instructions
  • Adding the comparison table at the end is optional.
  • The number of decimal places to use in the comparison table is up to the user's discretion, as long as it is self-consistent within the table.
Where this section should be placed on an edo page
  • Synopsis & infobox
  • (Any foundational introductory subsections)
  • Theory
    • Harmonics
    • (Any short subsections about theory unique to the edo)
    • Additional properties
    • Subsets and supersets
  • Interval table
  • Notation
  • (Any long subsections about theory unique to the edo)
  • Approximation to JI
  • Regular temperament properties
    • Uniform maps
    • Commas
    • Rank-2 temperaments
  • OCTAVE STRETCH OR COMPRESSION
  • Scales
  • (Any subsections about practice unique to the edo)
  • Instruments
  • Music
  • See also
  • Notes
  • Further reading
  • External links

Note: This particular set of headings in this order is only how most edo pages look at the moment, but it might be replaced with a more intuitive standard in the future. If and when that happens, this guideline should be modified to adopt that new standard.

Plan for roll-out

Edo pages which currently have an "octave stretch", "related tunings", "zeta properties", etc. section:

This standard will need to be rolled out to those above pages.

It can optionally be rolled out to other edo pages later.

Things to note
  • When rolling it out try not to delete existing body text but instead rework it where possible.
  • This section will not replace any "n-edo and octave stretch" pages. Still, add this section to the relevant edo page, but also link to the "n-edo and octave stretch" page at the top of this section, using the see also Template, eg: "{{See also|36edo and octave stretch}}".

Example (36edo)

Octave stretch or compression

What follows is a comparison of stretched- and compressed-octave 36edo tunings.


21edf
  • Step size: 33.426 ¢
  • Octave size: 1203.3 ¢
Approximation of harmonics in 21edf
Harmonic 2 3 4 5 6 7 8 9 10 11 12 13
Error Absolute (¢) +3.4 +3.4 +6.7 -11.9 +6.7 +7.2 +10.1 +6.7 -8.6 -6.4 +10.1 +5.2
Relative (%) +10.0 +10.0 +20.1 -35.7 +20.1 +21.7 +30.1 +20.1 -25.6 -19.3 +30.1 +15.5
Steps
(reduced)
36
(15)
57
(15)
72
(9)
83
(20)
93
(9)
101
(17)
108
(3)
114
(9)
119
(14)
124
(19)
129
(3)
133
(7)
Approximation of harmonics in 21edf (continued)
Harmonic 13 14 15 16 17 18 19 20 21 22 23 24
Error Absolute (¢) +5.2 +10.6 -8.6 +13.4 +8.7 +10.1 -16.7 -5.2 +10.6 -3.1 -13.2 +13.4
Relative (%) +15.5 +31.7 -25.6 +40.1 +26.1 +30.1 -49.9 -15.6 +31.7 -9.2 -39.5 +40.1
Steps
(reduced)
133
(7)
137
(11)
140
(14)
144
(18)
147
(0)
150
(3)
152
(5)
155
(8)
158
(11)
160
(13)
162
(15)
165
(18)

Stretching the octave of 36edo by a little over 3 ¢ 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 ¢. The tuning 21edf does this.


57edt
  • Step size: 33.368 ¢
  • Octave size: 1201.2 ¢
Approximation of harmonics in 57edt
Harmonic 2 3 4 5 6 7 8 9 10 11 12 13
Error Absolute (¢) +1.2 +0.0 +2.5 +16.6 +1.2 +1.3 +3.7 +0.0 -15.6 -13.7 +2.5 -2.6
Relative (%) +3.7 +0.0 +7.4 +49.7 +3.7 +3.9 +11.1 +0.0 -46.6 -41.2 +7.4 -7.9
Steps
(reduced)
36
(36)
57
(0)
72
(15)
84
(27)
93
(36)
101
(44)
108
(51)
114
(0)
119
(5)
124
(10)
129
(15)
133
(19)
Approximation of harmonics in 57edt (continued)
Harmonic 13 14 15 16 17 18 19 20 21 22 23 24
Error Absolute (¢) -2.6 +2.5 +16.6 +4.9 +0.1 +1.2 +7.7 -14.3 +1.3 -12.5 +10.6 +3.7
Relative (%) -7.9 +7.6 +49.7 +14.8 +0.3 +3.7 +23.2 -42.9 +3.9 -37.5 +31.9 +11.1
Steps
(reduced)
133
(19)
137
(23)
141
(27)
144
(30)
147
(33)
150
(36)
153
(39)
155
(41)
158
(44)
160
(46)
163
(49)
165
(51)

If one intends to use both 36edo's vals for 5/1 at once, stretching the octave of 36edo by about 1 ¢ 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 ¢. Five almost-identical tunings do this: 57edt, 101ed7, 155zpi, and the TE and WE 2.3.7.13 subgroup WE tunings of 36edo.


Pure-octaves 36edo
  • Step size: 33.333 ¢
  • Octave size: 1200.0 ¢

Pure-octaves 36edo approximates all primes up to 11 within 15.3 ¢.


11-limit TE 36edo
  • Step size: 33.287 ¢
  • Octave size: 1198.3 ¢
Approximation of harmonics in 11lim WE-tuned 36edo
Harmonic 2 3 4 5 6 7 8 9 10 11 12 13
Error Absolute (¢) -1.7 -4.6 -3.3 +9.8 -6.3 -6.8 -5.0 -9.2 +8.1 +9.6 -7.9 -13.4
Relative (%) -5.0 -13.8 -10.0 +29.4 -18.8 -20.5 -15.0 -27.6 +24.4 +28.7 -23.8 -40.1
Step 36 57 72 84 93 101 108 114 120 125 129 133
Approximation of harmonics in 11lim WE-tuned 36edo (continued)
Harmonic 13 14 15 16 17 18 19 20 21 22 23 24
Error Absolute (¢) -13.4 -8.5 +5.2 -6.7 -11.8 -10.9 -4.6 +6.5 -11.4 +7.9 -2.5 -9.6
Relative (%) -40.1 -25.6 +15.6 -20.0 -35.3 -32.6 -13.8 +19.4 -34.4 +23.7 -7.5 -28.8
Step 133 137 141 144 147 150 153 156 158 161 163 165

Compressing the octave of 36edo by about 2 ¢ 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 ¢. The 11- and 13-limit TE tunings of 36edo both do this, as do their respective WE tunings.


Stretched/compressed tunings comparison table
Tuning Step size
(cents)
Prime error (cents) Mapping of primes 2–13 (steps) Octave stretch
2 3 5 7 11 13
21edf 33.426 +3.3 +3.3 −12.0 +7.2 −6.5 +5.1 36, 57, 83, 101, 124, 133 +0.275%
57edt 33.368 +1.2 0.0 +16.6 +1.3 −13.7 −2.6 36, 57, 84, 101, 124, 133 +0.001%
155zpi 33.346 +0.6 −1.0 +15.1 −0.5 −16.0 −5.0 36, 57, 83, 101, 124, 133 +0.0005%
36edo 33.333 0.0 −2.0 +13.7 −2.2 +15.3 −7.2 36, 57, 84, 101, 125, 133 0%
13-limit WE 33.302 −1.1 −3.7 +11.1 −5.3 +11.4 −11.4 36, 57, 84, 101, 125, 133 -0.0009%
11-limit WE 33.286 −1.7 −4.7 +9.7 −6.9 +9.4 −13.5 36, 57, 84, 101, 125, 133 -0.00142%