87edo: Difference between revisions
Wikispaces>genewardsmith **Imported revision 485345004 - Original comment: ** |
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{{Infobox ET}} | |||
{{ED intro}} | |||
== Theory == | |||
87edo is solid as both a [[13-limit]] (or [[15-odd-limit]]) and as a [[5-limit]] system, and does well enough in any limit in between. It is the smallest edo that is [[distinctly consistent]] in the [[13-odd-limit]] [[tonality diamond]], the smallest edo that is [[purely consistent]]{{idiosyncratic}} in the [[15-odd-limit]] (maintains [[relative interval error]]s of no greater than 25% on all of the first 16 [[harmonic]]s of the [[harmonic series]]). It is also a [[zeta peak integer edo]]. Since {{nowrap|87 {{=}} 3 × 29}}, 87edo shares the same perfect fifth with [[29edo]]. | |||
87edo also shows some potential in limits beyond 13. The next four prime harmonics [[17/1|17]], [[19/1|19]], [[23/1|23]], and [[29/1|29]] are all near-critically sharp, but the feature of it is that the overtones and undertones are distinct, and most intervals are usable as long as they do not combine with [[7/1|7]], which is flat. Actually, as a no-sevens system, it is consistent in the 33-odd-limit. | |||
It [[tempering out|tempers out]] 15625/15552 ([[15625/15552|kleisma]]), {{monzo| 26 -12 -3 }} ([[misty comma]]), and {{monzo| 46 -29 }} ([[29-comma]]) in the 5-limit, in addition to [[245/243]], [[1029/1024]], [[3136/3125]], and [[5120/5103]] in the 7-limit. In the 13-limit, notably [[196/195]], [[325/324]], [[352/351]], [[364/363]], [[385/384]], [[441/440]], [[625/624]], [[676/675]], and [[1001/1000]]. | |||
| | |||
87 | 87edo is a particularly good tuning for [[rodan]], the {{nowrap|41 & 46}} temperament. The 8/7 generator of 17\87 is a remarkable 0.00061{{c}} sharper than the 13-limit [[CWE tuning|CWE generator]]. Also, the 32\87 generator for [[Kleismic family #Clyde|clyde temperament]] is 0.01479{{c}} sharp of the 13-limit CWE generator. | ||
=== Prime harmonics === | |||
In higher limits it excels as a [[subgroup]] temperament, especially as an incomplete 71-limit temperament with [[128/127]] and [[129/128]] (the subharmonic and harmonic hemicomma-sized intervals, respectively) mapped accurately to a single step. Generalizing a single step of 87edo harmonically yields harmonics 115 through 138, which when detempered is the beginning of the construction of [[Ringer scale|Ringer]] 87, thus tempering [[S-expression|S116 through S137]] by patent val and corresponding to the gravity of the fact that 87edo is a circle of [[126/125]]'s, meaning ([[126/125]])<sup>87</sup> only very slightly exceeds the octave. | |||
{{Harmonics in equal|87|columns=12}} | |||
{{Harmonics in equal|87|columns=12|start=13|collapsed=1|title=Approximation of prime harmonics in 87edo (continued)}} | |||
= | === Subsets and supersets === | ||
[ | 87edo contains [[3edo]] and [[29edo]] as subset edos. | ||
= | == Intervals == | ||
{| class="wikitable center-all right-2 left-3 left-4" | |||
|- | |||
! rowspan="2" | # | |||
! rowspan="2" | Cents | |||
! colspan="2" | Approximated ratios | |||
! colspan="2" rowspan="2" | [[Ups and downs notation]] | |||
|- | |||
! 13-limit | |||
! 31-limit extension | |||
|- | |||
| 0 | |||
| 0.0 | |||
| [[1/1]] | |||
| | |||
| P1 | |||
| D | |||
|- | |||
| 1 | |||
| 13.8 | |||
| [[91/90]], [[100/99]], [[126/125]] | |||
| | |||
| ^1 | |||
| ^D | |||
|- | |||
| 2 | |||
| 27.6 | |||
| ''[[49/48]]'', [[55/54]], [[64/63]], [[65/64]], [[81/80]] | |||
| | |||
| ^^1 | |||
| ^^D | |||
|- | |||
| 3 | |||
| 41.4 | |||
| [[40/39]], [[45/44]], [[50/49]] | |||
| [[39/38]] | |||
| ^<sup>3</sup>1 | |||
| ^<sup>3</sup>D/v<sup>3</sup>Eb | |||
|- | |||
| 4 | |||
| 55.2 | |||
| ''[[28/27]]'', [[33/32]], [[36/35]] | |||
| [[30/29]], [[31/30]], [[32/31]], [[34/33]] | |||
| vvm2 | |||
| vvEb | |||
|- | |||
| 5 | |||
| 69.0 | |||
| [[25/24]], [[26/25]], [[27/26]] | |||
| [[24/23]] | |||
| vm2 | |||
| vEb | |||
|- | |||
| 6 | |||
| 82.8 | |||
| [[21/20]], [[22/21]] | |||
| [[20/19]], [[23/22]] | |||
| m2 | |||
| Eb | |||
|- | |||
| 7 | |||
| 96.6 | |||
| [[35/33]] | |||
| [[18/17]], [[19/18]] | |||
| ^m2 | |||
| ^Eb | |||
|- | |||
| 8 | |||
| 110.3 | |||
| [[16/15]] | |||
| [[17/16]], [[31/29]], [[33/31]] | |||
| ^^m2 | |||
| ^^Eb | |||
|- | |||
| 9 | |||
| 124.1 | |||
| [[14/13]], [[15/14]] | |||
| [[29/27]] | |||
| vv~2 | |||
| ^<sup>3</sup>Eb | |||
|- | |||
| 10 | |||
| 137.9 | |||
| [[13/12]], [[27/25]] | |||
| [[25/23]] | |||
| v~2 | |||
| ^<sup>4</sup>Eb | |||
|- | |||
| 11 | |||
| 151.7 | |||
| [[12/11]], [[35/32]] | |||
| | |||
| ^~2 | |||
| v<sup>4</sup>E | |||
|- | |||
| 12 | |||
| 165.5 | |||
| [[11/10]] | |||
| [[32/29]], [[34/31]] | |||
| ^^~2 | |||
| v<sup>3</sup>E | |||
|- | |||
| 13 | |||
| 179.3 | |||
| [[10/9]] | |||
| | |||
| vvM2 | |||
| vvE | |||
|- | |||
| 14 | |||
| 193.1 | |||
| [[28/25]] | |||
| [[19/17]], [[29/26]] | |||
| vM2 | |||
| vE | |||
|- | |||
| 15 | |||
| 206.9 | |||
| [[9/8]] | |||
| [[26/23]] | |||
| M2 | |||
| E | |||
|- | |||
| 16 | |||
| 220.7 | |||
| [[25/22]] | |||
| [[17/15]], [[33/29]] | |||
| ^M2 | |||
| ^E | |||
|- | |||
| 17 | |||
| 234.5 | |||
| [[8/7]] | |||
| [[31/27]] | |||
| ^^M2 | |||
| ^^E | |||
|- | |||
| 18 | |||
| 248.3 | |||
| [[15/13]] | |||
| [[22/19]], [[23/20]], [[38/33]] | |||
| ^<sup>3</sup>M2/v<sup>3</sup>m3 | |||
| ^<sup>3</sup>E/v<sup>3</sup>F | |||
|- | |||
| 19 | |||
| 262.1 | |||
| [[7/6]] | |||
| [[29/25]], [[36/31]] | |||
| vvm3 | |||
| vvF | |||
|- | |||
| 20 | |||
| 275.9 | |||
| [[75/64]] | |||
| [[20/17]], [[27/23]], [[34/29]] | |||
| vm3 | |||
| vF | |||
|- | |||
| 21 | |||
| 289.7 | |||
| [[13/11]], [[32/27]], [[33/28]] | |||
| | |||
| m3 | |||
| F | |||
|- | |||
| 22 | |||
| 303.4 | |||
| [[25/21]] | |||
| [[19/16]], [[31/26]] | |||
| ^m3 | |||
| ^F | |||
|- | |||
| 23 | |||
| 317.2 | |||
| [[6/5]] | |||
| | |||
| ^^m3 | |||
| ^^F | |||
|- | |||
| 24 | |||
| 331.0 | |||
| [[40/33]] | |||
| [[23/19]], [[29/24]] | |||
| vv~3 | |||
| ^<sup>3</sup>F | |||
|- | |||
| 25 | |||
| 344.8 | |||
| [[11/9]], [[39/32]] | |||
| | |||
| v~3 | |||
| ^<sup>4</sup>F | |||
|- | |||
| 26 | |||
| 358.6 | |||
| [[16/13]], [[27/22]] | |||
| [[38/31]] | |||
| ^~3 | |||
| v<sup>4</sup>F# | |||
|- | |||
| 27 | |||
| 372.4 | |||
| [[26/21]] | |||
| [[31/25]], [[36/29]] | |||
| ^^3 | |||
| v<sup>3</sup>F# | |||
|- | |||
| 28 | |||
| 386.2 | |||
| [[5/4]] | |||
| | |||
| vvM3 | |||
| vvF# | |||
|- | |||
| 29 | |||
| 400.0 | |||
| [[44/35]] | |||
| [[24/19]], [[29/23]], [[34/27]] | |||
| vM3 | |||
| vF# | |||
|- | |||
| 30 | |||
| 413.8 | |||
| [[14/11]], [[33/26]], [[81/64]] | |||
| [[19/15]] | |||
| M3 | |||
| F# | |||
|- | |||
| 31 | |||
| 427.6 | |||
| [[32/25]] | |||
| [[23/18]] | |||
| ^M3 | |||
| ^F# | |||
|- | |||
| 32 | |||
| 441.4 | |||
| [[9/7]], [[35/27]] | |||
| [[22/17]], [[31/24]], [[40/31]] | |||
| ^^M3 | |||
| ^^F# | |||
|- | |||
| 33 | |||
| 455.2 | |||
| [[13/10]] | |||
| [[30/23]] | |||
| ^<sup>3</sup>M3/v<sup>3</sup>4 | |||
| ^<sup>3</sup>F#/v<sup>3</sup>G | |||
|- | |||
| 34 | |||
| 469.0 | |||
| [[21/16]] | |||
| [[17/13]], [[25/19]], [[38/29]] | |||
| vv4 | |||
| vvG | |||
|- | |||
| 35 | |||
| 482.8 | |||
| [[33/25]] | |||
| | |||
| v4 | |||
| vG | |||
|- | |||
| 36 | |||
| 496.6 | |||
| [[4/3]] | |||
| | |||
| P4 | |||
| G | |||
|- | |||
| 37 | |||
| 510.3 | |||
| [[35/26]] | |||
| [[31/23]] | |||
| ^4 | |||
| ^G | |||
|- | |||
| 38 | |||
| 524.1 | |||
| [[27/20]] | |||
| [[23/17]] | |||
| ^^4 | |||
| ^^G | |||
|- | |||
| 39 | |||
| 537.9 | |||
| [[15/11]] | |||
| [[26/19]], [[34/25]] | |||
| ^<sup>3</sup>4 | |||
| ^<sup>3</sup>G | |||
|- | |||
| 40 | |||
| 551.7 | |||
| [[11/8]], [[48/35]] | |||
| | |||
| ^<sup>4</sup>4 | |||
| ^<sup>4</sup>G | |||
|- | |||
| 41 | |||
| 565.5 | |||
| [[18/13]] | |||
| [[32/23]] | |||
| v<sup>4</sup>A4, vd5 | |||
| v<sup>4</sup>G#, vAb | |||
|- | |||
| 42 | |||
| 579.3 | |||
| [[7/5]] | |||
| [[46/33]] | |||
| v<sup>3</sup>A4, d5 | |||
| v<sup>3</sup>G#, Ab | |||
|- | |||
| 43 | |||
| 593.1 | |||
| [[45/32]] | |||
| [[24/17]], [[31/22]], [[38/27]] | |||
| vvA4, ^d5 | |||
| vvG#, ^Ab | |||
|- | |||
| … | |||
| … | |||
| … | |||
| … | |||
| … | |||
| … | |||
|} | |||
== Approximation to JI == | |||
=== Interval mappings === | |||
{{Q-odd-limit intervals|87}} | |||
== Regular temperament properties == | |||
{| class="wikitable center-4 center-5 center-6" | |||
|- | |||
! rowspan="2" | [[Subgroup]] | |||
! rowspan="2" | [[Comma list]] | |||
! rowspan="2" | [[Mapping]] | |||
! rowspan="2" | Optimal<br>8ve stretch (¢) | |||
! colspan="2" | Tuning error | |||
|- | |||
! [[TE error|Absolute]] (¢) | |||
! [[TE simple badness|Relative]] (%) | |||
|- | |||
| 2.3.5 | |||
| 15625/15552, 67108864/66430125 | |||
| {{mapping| 87 138 202 }} | |||
| −0.299 | |||
| 0.455 | |||
| 3.30 | |||
|- | |||
| 2.3.5.7 | |||
| 245/243, 1029/1024, 3136/3125 | |||
| {{mapping| 87 138 202 244 }} | |||
| +0.070 | |||
| 0.752 | |||
| 5.45 | |||
|- | |||
| 2.3.5.7.11 | |||
| 245/243, 385/384, 441/440, 3136/3125 | |||
| {{mapping| 87 138 202 244 301 }} | |||
| +0.033 | |||
| 0.676 | |||
| 4.90 | |||
|- | |||
| 2.3.5.7.11.13 | |||
| 196/195, 245/243, 352/351, 364/363, 625/624 | |||
| {{mapping| 87 138 202 244 301 322 }} | |||
| −0.011 | |||
| 0.625 | |||
| 4.53 | |||
|- | |||
| 2.3.5.7.11.13.17 | |||
| 154/153, 196/195, 245/243, 273/272, 364/363, 375/374 | |||
| {{mapping| 87 138 202 244 301 322 356 }} | |||
| −0.198 | |||
| 0.738 | |||
| 5.35 | |||
|- | |||
| 2.3.5.7.11.13.17.19 | |||
| 154/153, 196/195, 210/209, 245/243, 273/272, 286/285, 364/363 | |||
| {{mapping| 87 138 202 244 301 322 356 370 }} | |||
| −0.348 | |||
| 0.796 | |||
| 5.77 | |||
|} | |||
=== 13-limit detempering === | |||
{{Main|87edo/13-limit detempering}} | |||
=== Rank-2 temperaments === | |||
{| class="wikitable center-all left-5" | |||
|+ style="font-size: 105%;" | Table of rank-2 temperaments by generator | |||
|- | |||
[ | ! Periods<br>per 8ve | ||
! Generator* | |||
! Cents* | |||
! Associated<br>ratio* | |||
! Temperament | |||
|- | |||
| 1 | |||
| 2\87 | |||
| 27.586 | |||
| 64/63 | |||
| [[Arch]] | |||
|- | |||
| 1 | |||
| 4\87 | |||
| 55.172 | |||
| 33/32 | |||
| [[Escapade]] / [[escaped]] / [[alphaquarter]] | |||
|- | |||
| 1 | |||
| 10\87 | |||
| 137.931 | |||
| 13/12 | |||
| [[Quartemka]] | |||
|- | |||
| 1 | |||
| 14\87 | |||
| 193.103 | |||
| 28/25 | |||
| [[Luna]] / [[didacus]] / [[hemithirds]] | |||
|- | |||
| 1 | |||
| 17\87 | |||
| 234.483 | |||
| 8/7 | |||
| [[Slendric]] / [[rodan]] | |||
|- | |||
| 1 | |||
| 23\87 | |||
| 317.241 | |||
| 6/5 | |||
| [[Hanson]] / [[countercata]] / [[metakleismic]] | |||
|- | |||
| 1 | |||
| 26\87 | |||
| 358.621 | |||
| 16/13 | |||
| [[Restles]] | |||
|- | |||
| 1 | |||
| 32\87 | |||
| 441.379 | |||
| 9/7 | |||
| [[Clyde]] | |||
|- | |||
| 1 | |||
| 38\87 | |||
| 524.138 | |||
| 65/48 | |||
| [[Widefourth]] | |||
|- | |||
| 1 | |||
| 40\87 | |||
| 551.724 | |||
| 11/8 | |||
| [[Emka]] / [[emkay]] | |||
|- | |||
| 3 | |||
| 18\87<br>(11\87) | |||
| 248.276<br>(151.724) | |||
| 15/13<br>(12/11) | |||
| [[Hemimist]] | |||
|- | |||
| 3 | |||
| 23\87<br>(6\87) | |||
| 317.241<br>(82.759) | |||
| 6/5<br>(21/20) | |||
| [[Tritikleismic]] | |||
|- | |||
| 3 | |||
| 28\87<br>(1\87) | |||
| 386.207<br>(13.793) | |||
| 5/4<br>(126/125) | |||
| [[Mutt]] | |||
|- | |||
| 3 | |||
| 36\87<br>(7\87) | |||
| 496.552<br>(96.552) | |||
| 4/3<br>(18/17~19/18) | |||
| [[Misty]] | |||
|- | |||
| 29 | |||
| 28\87<br>(1\87) | |||
| 386.207<br>(13.793) | |||
| 5/4<br>(121/120) | |||
| [[Mystery]] | |||
|} | |||
<nowiki/>* [[Normal lists|Octave-reduced form]], reduced to the first half-octave, and [[Normal lists|minimal form]] in parentheses if distinct | |||
87 can serve as a mos in these: | |||
* [[Avicenna (temperament)|Avicenna]] ([[Breed|87 & 270]]) | |||
* [[Breed|87 & 494]] | |||
== Scales == | |||
=== Mos scales === | |||
{{main|List of MOS scales in 87edo}} | |||
=== Harmonic scales === | |||
87edo accurately approximates the mode 8 of [[harmonic series]], and the only interval pair not distinct is 14/13 and 15/14. It can also do mode 12 decently. | |||
==== (Mode 8) ==== | |||
{| class="wikitable center-all" | |||
|- | |||
! Overtones | |||
| 8 | |||
| 9 | |||
| 10 | |||
| 11 | |||
| 12 | |||
| 13 | |||
| 14 | |||
| 15 | |||
| 16 | |||
|- | |||
! JI Ratios | |||
| 1/1 | |||
| 9/8 | |||
| 5/4 | |||
| 11/8 | |||
| 3/2 | |||
| 13/8 | |||
| 7/4 | |||
| 15/8 | |||
| 2/1 | |||
|- | |||
! … in cents | |||
| 0.0 | |||
| 203.9 | |||
| 386.3 | |||
| 551.3 | |||
| 702.0 | |||
| 840.5 | |||
| 968.8 | |||
| 1088.3 | |||
| 1200.0 | |||
|- | |||
! Degrees in 87edo | |||
| 0 | |||
| 15 | |||
| 28 | |||
| 40 | |||
| 51 | |||
| 61 | |||
| 70 | |||
| 79 | |||
| 87 | |||
|- | |||
! … in cents | |||
| 0.0 | |||
| 206.9 | |||
| 386.2 | |||
| 551.7 | |||
| 703.5 | |||
| 841.4 | |||
| 965.5 | |||
| 1089.7 | |||
| 1200.0 | |||
|} | |||
The scale in adjacent steps is 15, 13, 12, 11, 10, 9, 9, 8. | |||
==== (Mode 12) ==== | |||
{| class="wikitable center-all" | |||
|- | |||
! Overtones | |||
| 12 | |||
| 13 | |||
| 14 | |||
| 15 | |||
| 16 | |||
| 17 | |||
| 18 | |||
| 19 | |||
| 20 | |||
| 21 | |||
| 22 | |||
| 23 | |||
| 24 | |||
|- | |||
! JI Ratios | |||
| 1/1 | |||
| 13/12 | |||
| 7/6 | |||
| 5/4 | |||
| 4/3 | |||
| 17/12 | |||
| 3/2 | |||
| 19/12 | |||
| 5/3 | |||
| 7/4 | |||
| 11/6 | |||
| 23/12 | |||
| 2/1 | |||
|- | |||
! … in cents | |||
| 0.0 | |||
| 138.6 | |||
| 266.9 | |||
| 386.3 | |||
| 498.0 | |||
| 603.0 | |||
| 702.0 | |||
| 795.6 | |||
| 884.4 | |||
| 968.8 | |||
| 1049.4 | |||
| 1126.3 | |||
| 1200.0 | |||
|- | |||
! Degrees in 87edo | |||
| 0 | |||
| 10 | |||
| 19 | |||
| 28 | |||
| 36 | |||
| 44 | |||
| 51 | |||
| 58 | |||
| 64 | |||
| 70 | |||
| 76 | |||
| 82 | |||
| 87 | |||
|- | |||
! … in cents | |||
| 0.0 | |||
| 137.9 | |||
| 262.1 | |||
| 386.2 | |||
| 496.6 | |||
| 606.9 | |||
| 703.4 | |||
| 800.0 | |||
| 882.8 | |||
| 965.5 | |||
| 1048.3 | |||
| 1131.0 | |||
| 1200.0 | |||
|} | |||
The scale in adjacent steps is 10, 9, 9, 8, 7, 7, 6, 6, 6, 6, 5. | |||
13, 15, 16, 18, 20, and 22 are close matches. | |||
14 and 21 are flat; 17, 19, and 23 are sharp. Still decent all things considered. | |||
=== Other scales === | |||
* [[Sequar5m]] | |||
== Instruments == | |||
* [[Lumatone mapping for 87edo]] | |||
* [[Skip fretting system 87 2 17]] | |||
== Music == | |||
; [[Bryan Deister]] | |||
* [https://www.youtube.com/shorts/ecxELXmkYAs ''microtonal improvisation in 87edo''] (2025) | |||
; [[Gene Ward Smith]] | |||
* ''Pianodactyl'' (archived 2010) – [https://soundcloud.com/genewardsmith/pianodactyl SoundCloud] | [http://www.archive.org/details/Pianodactyl detail] | [http://www.archive.org/download/Pianodactyl/pianodactyl.mp3 play] – rodan[26] in 87edo tuning | |||
[[Category:Zeta|##]] <!-- 2-digit number --> | |||
[[Category:Listen]] | |||
[[Category:Clyde]] | |||
[[Category:Countercata]] | |||
[[Category:Hemithirds]] | |||
[[Category:Mystery]] | |||
[[Category:Rodan]] | |||
[[Category:Tritikleismic]] |