684edo: Difference between revisions

Improve intro; +prime error table
+infobox; +RTT table and rank-2 temperaments
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{{Infobox ET
| Prime factorization = 2<sup>2</sup> × 3<sup>2</sup> × 19
| Step size = 1.75439¢
| Fifth = 400\684 (701.75¢) (→ [[171edo|100\171]])
| Semitones = 64:52 (112.28¢ : 91.23¢)
| Consistency = 17
}}
{{EDO intro|684}}  
{{EDO intro|684}}  


== Theory ==
684edo divides the steps of [[171edo]] into four. It is [[consistent]] to the 17-odd-limit, tempering out [[2401/2400]], [[3025/3024]], [[4225/4224]], [[4375/4374]], and [[32805/32768]] in the 13-limit; [[1089/1088]], [[1225/1224]], [[1701/1700]], [[2025/2023]], 2058/2057, 2500/2499, 8624/8619, and 14875/14872 in the 17-limit.
684edo divides the steps of [[171edo]] into four. It is [[consistent]] to the 17-odd-limit, tempering out [[2401/2400]], [[3025/3024]], [[4225/4224]], [[4375/4374]], and [[32805/32768]] in the 13-limit; [[1089/1088]], [[1225/1224]], [[1701/1700]], [[2025/2023]], 2058/2057, 2500/2499, 8624/8619, and 14875/14872 in the 17-limit.


=== Prime harmonics ===
{{Harmonics in equal|684|columns=11}}
{{Harmonics in equal|684|columns=11}}
== Regular temperament properties ==
{| class="wikitable center-4 center-5 center-6"
! rowspan="2" | [[Subgroup]]
! rowspan="2" | [[Comma list|Comma List]]
! rowspan="2" | [[Mapping]]
! rowspan="2" | Optimal<br>8ve stretch (¢)
! colspan="2" | Tuning error
|-
! [[TE error|Absolute]] (¢)
! [[TE simple badness|Relative]] (%)
|-
| 2.3.5.7.11.13
| 2401/2400, 3025/3024, 4225/4224, 4375/4374, 32805/32768
| [{{val| 684 1084 1588 1920 2366 2531 }}]
| +0.0994
| 0.0558
| 3.18
|-
| 2.3.5.7.11.13.17
| 1089/1088, 1701/1700, 2025/2023, 2058/2057, 4225/4224, 13013/13005
| [{{val| 684 1084 1588 1920 2366 2531 2796 }}]
| +0.0744
| 0.0800
| 4.56
|}
* 684et is the first equal temperament with a lower 13-limit absolute error after 494. The next equal temperament that is better tuned is 764.
=== Rank-2 temperaments ===
{| class="wikitable center-all left-5"
|+Table of rank-2 temperaments by generator
! Periods<br>per Octave
! Generator<br>(Reduced)
! Cents<br>(Reduced)
! Associated<br>Ratio
! Temperaments
|-
| 18
| 271\684<br>(5\684)
| 475.44<br>(8.77)
| 1053/800<br>(1287/1280)
| [[Semihemiennealimmal]]
|}


[[Category:Equal divisions of the octave|###]] <!-- 3-digit number -->
[[Category:Equal divisions of the octave|###]] <!-- 3-digit number -->