Chalmersia: Difference between revisions
changed the phrase "but these are probably mistakes" to "though at least some of these are mistakes" as judging from from some of the archived conversations on this wiki about this comma, it seems that some people actually think that the ending of the name "chalmersia" is a bit weird |
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{{Infobox Interval | {{Infobox Interval | ||
| Ratio = 123201/123200 | | Ratio = 123201/123200 | ||
| Name = chalmersia | | Name = chalmersia | ||
| Color name = Lathotholurugugu comma | | Color name = Lathotholurugugu comma | ||
| | | Comma = yes | ||
}} | }} | ||
The '''chalmersia''' | The '''chalmersia''' is an [[unnoticeable comma|unnoticeable]] [[13-limit]] comma with a ratio of '''123201/123200''' and a size of approximately 0.014{{cent}}. It is the smallest 13-limit [[superparticular]] comma. Tempering it out equates [[351/350]] and [[352/351]], thus splitting [[176/175]] into two, and equates 385/351 and 351/320, thus splitting [[77/64]] into two: these are properties characteristic of '''chalmersic temperaments'''. In addition, it equates a stack consisting of a [[729/512]] tritone plus a [[169/128]] grave fourth with a stack consisting of a [[25/16]] augmented fifth plus a [[77/64]] minor third; it splits [[81/77]] into two [[40/39]]s; and it splits the pythagorean limma [[256/243]] into [[26/25]] and [[78/77]]. | ||
It factors into the two smallest 17-limit superparticular ratios: 123201/123200 = (194481/194480)(336141/336140). | |||
== Temperaments == | |||
Tempering out the comma in the full 13-limit gives the rank-5 '''chalmersic temperament'''. | |||
[[Subgroup]]: 2.3.5.7.11.13 | |||
[[Mapping]]: <br> | |||
{| class="right-all" | |||
| [⟨ || 1 || 1 || 2 || 2 || 2 || 4 || ], | |||
|- | |||
| ⟨ || 0 || 1 || 0 || 0 || 0 || -3 || ], | |||
|- | |||
| ⟨ || 0 || 0 || 1 || 0 || 0 || 1 || ], | |||
|- | |||
| ⟨ || 0 || 0 || 0 || 1 || 1 || 1 || ], | |||
|- | |||
| ⟨ || 0 || 0 || 0 || 0 || 2 || 1 || ]] | |||
|} | |||
: mapping generators: ~2, ~3, ~5, ~7, ~351/280 | |||
[[Optimal tuning]]s: | |||
* [[CTE]]: ~2 = 1\1, ~3/2 = 701.9539, ~5/4 = 386.3145, ~7/4 = 3368.8265, ~351/280 = 391.2462 | |||
* [[CWE]]: ~2 = 1\1, ~3/2 = 701.9536, ~5/4 = 386.3140, ~7/4 = 3368.8259, ~351/280 = 391.2461 | |||
{{Optimal ET sequence|legend=1| 12f, 19e, 22, 27e, 31, 46, 53, 58, 80, 104c, 111, 159, 190, 217, 224, 270, 494, 684, 764, 935, 954, 1178, 1236, 1448, 1506, 2190, 2684, 3395, 4079, 4349, 4843, 5585, 6079, 8269, 8539, … }} | |||
== Etymology == | |||
The chalmersia was named by [[Gene Ward Smith]] in 2003 after [[John Chalmers]]<ref>[https://yahootuninggroupsultimatebackup.github.io/tuning-math/topicId_7316.html Yahoo! Tuning Group | ''Nameable 13-limit'']</ref>. | |||
:''The remarkable 123201/123200 might be named the chalmersia, since John Chalmers is presumably the first to see it.'' | |||
—Gene Ward Smith | |||
== See also == | == See also == | ||
Line 16: | Line 46: | ||
* [[List of superparticular intervals]] | * [[List of superparticular intervals]] | ||
== | == Notes == | ||
[[Category: | [[Category:Chalmersic]] | ||
[[Category: | [[Category:Commas named after music theorists]] | ||