Cataharry comma: Difference between revisions

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{{Infobox Interval
{{Infobox Interval
| Icon =
| Ratio = 19683/19600
| Ratio = 19683/19600
| Monzo = -4 9 -2 -2
| Cents = 7.31577
| Name = cataharry comma
| Name = cataharry comma
| Color name =
| Color name = Lrrgg-2, Labirugu comma
| FJS name =
| Comma = yes
| Sound =  
}}
}}
The '''cataharry comma''' ([[ratio]]: 19683/19600, {{monzo|legend=1| -4 9 -2 -2 }}) is a [[small comma|small]] [[7-limit]] [[comma]] measuring about 6.1 [[cent]]s. It is the difference between the [[81/70|septimal ultramajor second (81/70)]] and its [[fourth complement]].


The '''cataharry comma''' ('''19683/19600''') is a [[7-limit]] [[comma]] measuring about 6.1 cents. It is the difference between the [[81/70|septimal ultramajor second (81/70)]] and its [[fourth complement]]. In terms of commas, it is equal to ([[81/80]])/([[245/243]]) and to ([[81/80]])<sup>2</sup>/([[49/48]]). The latter equivalence implies that if the cataharry comma is tempered out and if neither [[81/80]] nor [[49/48]] are tempered out, there will be an interval ~[[81/80]] above [[8/7]] and ~[[81/80]] below [[7/6]], and analogously for [[12/7]] and [[7/4]].
In terms of commas, it is equal to ([[81/80]])/([[245/243]]) and to ([[81/80]])<sup>2</sup>/([[49/48]]). The latter equivalence implies that if the cataharry comma is tempered out and if neither [[81/80]] nor [[49/48]] are tempered out, there will be an interval ~[[81/80]] above [[8/7]] and ~[[81/80]] below [[7/6]], and analogously for [[12/7]] and [[7/4]].
 
In the 13-limit, this comma factors into ([[351/350]])⋅([[729/728]]), which equals ([[676/675]])⋅(729/728)<sup>2</sup>, making it a [[lopsided comma]] with [[S-expression]] S26⋅S27<sup>2</sup>.  


== Temperaments ==
== Temperaments ==
Tempering out this comma leads to the rank-3 [[cataharry family]] of temperaments, which splits the [[4/3|just perfect fourth (4/3)]] into two exact hemifourths, each representing 81/70~280/243.  
[[Tempering out]] this comma leads to the rank-3 [[cataharry]] temperament, which splits the [[4/3|just perfect fourth (4/3)]] into two exact hemifourths, each representing 81/70~280/243.
 
See [[Cataharry family]] for the rank-3 family where it is tempered out. See [[Cataharry temperaments]] for a collection of rank-2 temperaments where it is tempered out.
 
== Etymology ==
The name ''cataharry'' was given by [[Gene Ward Smith]] in 2005 as a contraction of ''[[catakleismic]]'' and ''[[harry]]''<ref>[https://yahootuninggroupsultimatebackup.github.io/tuning-math/topicId_12900.html Yahoo! Tuning Group | ''Seven limit comma names from pairs of temperament names'']</ref>.  


== See also ==
== References ==
* [[Cataharry family]], the rank-3 family where it is tempered out
* [[Cataharry temperaments]], a collection of rank-2 temperaments where it is tempered out
* [[Small comma]]


[[Category:7-limit]]
[[Category:Small comma]]
[[Category:Cataharry]]
[[Category:Cataharry]]
[[Category:Commas named by combining multiple temperament names]]
[[Category:Commas named after composers]]
[[Category:Commas named after music theorists]]