81/70: Difference between revisions

m Mention of enneadecal (and replace of old description)
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{{Infobox Interval
{{Infobox Interval
| Ratio = 81/70
| Name = septimal ultramajor second
| Monzo = -1 4 -1 -1
| Cents = 252.6804
| Name = septimal semiaugmented second, <br>septimal ultramajor second
| Color name = rg2, rugu 2nd
| Color name = rg2, rugu 2nd
| FJS name = M2<sub>35</sub>
| Sound = Ji-81-70-csound-foscil-220hz.mp3
| Sound = Ji-81-70-csound-foscil-220hz.mp3
}}
}}
'''81/70''', the '''septimal ultramajor second''' is a [[7-limit]] [[interseptimal]] ratio of about 253 [[cent]]s. It is sharp of a major second [[9/8]] by a septimal quartertone [[36/35]], sharp of a supermajor second [[8/7]] by a syntonic comma [[81/80]], and flat of a subminor third [[7/6]] by a sensamagic comma [[245/243]].


'''81/70''', the '''septimal semiaugmented second''' or '''septimal ultramajor second''' is a [[7-limit]] [[interseptimal]] ratio of about 253 cents. It is sharp of a major second [[9/8]] by a septimal quartertone [[36/35]], sharp of a supermajor second [[8/7]] by a syntonic comma [[81/80]], and flat of a subminor third [[7/6]] by a sensamagic comma [[245/243]].  
Notice it is also flat of the just minor third [[6/5]] by a subminor second [[28/27]]. For this fact it is useful in the [[sensamagic dominant chord]] where it functions as a dissonance yet to be resolved up to the minor third. The [[Canou family|canou temperament]] targets this progression and uses it as one of the generators.  


It is also flat of a minor third [[6/5]] by a subminor second [[28/27]]. For this fact it is useful in the [[Canovian chord]] and provides the function of a voice leading up to the minor third. The [[Canou family|canou temperament]] targets this progression and uses it as one of the generators.
== Approximation ==
 
It is near-perfectly approximated by [[19edo]] (4\19), with an error of 0.05 cents, and hence equally well done by the [[enneadecal]] temperament.
It is so perfectly approximated by [[19edo]] (4\19), with an error of 0.05 cents, and hence equally well done by the [[enneadecal]] temperament.  


== See also ==
== See also ==
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* [[Gallery of just intervals]]
* [[Gallery of just intervals]]


[[Category:7-limit]]
[[Category:Interval]]
[[Category:Ratio]]
[[Category:Second]]
[[Category:Second]]
[[Category:Supermajor second]]
[[Category:Supermajor second]]
[[Category:Interseptimal]]
[[Category:Interseptimal intervals]]
[[Category:Semifourth]]