68edo: Difference between revisions

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{{Infobox ET
{{Infobox ET
| Prime factorization = 2<sup>2</sup> × 17
| Prime factorization = 2<sup>2</sup> × 17
| Step size = 17.64706¢
| Step size = 17.6471¢
| Fifth = 40\68 (705.88¢) (→ [[17edo|10\17]])
| Fifth = 40\68 (705.) (→ [[17edo|10\17]])
| Semitones = 8:4 (141.18¢ : 70.59¢)
| Semitones = 8:4 (141.: 70.)
| Consistency = 9
| Consistency = 9
| Monotonicity = 27
}}
}}
The '''68 equal divisions of the octave''' ('''68edo'''), or the '''68(-tone) equal temperament''' ('''68tet''', '''68et''') when viewed from a [[regular temperament]] perspective, is the tuning system derived by dividing the [[octave]] into 68 [[equal]]ly-sized steps. Each step represents a frequency ratio of 17.65 [[cent]]s.  
The '''68 equal divisions of the octave''' ('''68edo'''), or the '''68(-tone) equal temperament''' ('''68tet''', '''68et''') when viewed from a [[regular temperament]] perspective, is the tuning system derived by dividing the [[octave]] into 68 [[equal]]ly-sized steps. Each step represents a frequency ratio of 17.65 [[cent]]s.  
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68edo's step is half of the step size of [[34edo]], which does well in the 5-limit but not so well in the 7-limit, and one quarter the size of [[17edo]], which does well in the [[3-limit]], but not so well in the [[5-limit]]. The luck continues: 68 is a strong [[7-limit]] system, but does not do as well for in [[11-limit]]; though it's certainly usable for that purpose, it does not represent the 11-limit diamond [[consistent]]ly.
68edo's step is half of the step size of [[34edo]], which does well in the 5-limit but not so well in the 7-limit, and one quarter the size of [[17edo]], which does well in the [[3-limit]], but not so well in the [[5-limit]]. The luck continues: 68 is a strong [[7-limit]] system, but does not do as well for in [[11-limit]]; though it's certainly usable for that purpose, it does not represent the 11-limit diamond [[consistent]]ly.


As a 7-limit system it tempers out [[Diaschisma|2048/2025]], [[245/243]], 4000/3969, [[15625/15552]], [[3136/3125]], [[6144/6125]] and [[2401/2400]]. It [[support]]s [[octacot]], [[shrutar]], [[hemiwürschmidt]], [[hemikleismic]], [[clyde]] and [[neptune]] temperaments, and supplies the [[optimal patent val]] for 11-limit [[hemikleismic]]. It is a sharp-tending system, with the third, fifth and seventh harmonics all sharp.
As a 7-limit system it tempers out [[2048/2025]], [[245/243]], 4000/3969, [[15625/15552]], [[3136/3125]], [[6144/6125]] and [[2401/2400]]. It [[support]]s [[octacot]], [[shrutar]], [[hemiwürschmidt]], [[hemikleismic]], [[clyde]] and [[neptune]] temperaments, and supplies the [[optimal patent val]] for 11-limit [[hemikleismic]]. It is a sharp-tending system, with the third, fifth and seventh harmonics all sharp.


The 3rd degree of 68edo can be used as a generator for [[23edo and octave stretching|stretched 23edo]]. It results in a 23edo scale with octaves stretched by 1 step of 68edo (octaves of 1217.65 cents).
The 3rd degree of 68edo can be used as a generator for [[23edo and octave stretching|stretched 23edo]]. It results in a 23edo scale with octaves stretched by 1 step of 68edo (octaves of 1217.65 cents).


=== Prime harmonics ===
=== Prime harmonics ===
{{Primes in edo|68}}
{{Harmonics in equal|68}}


== Intervals ==
== Intervals ==
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| 1200.00
| 1200.00
| 2/1
| 2/1
|}
== 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]] (%)
|-
| 2.3.5.7
| 245/243, 2048/2025, 2401/2400
| [{{val| 68 108 158 191 }}]
| -0.983
| 0.915
| 5.19
|}
|}