81/70: Difference between revisions

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'''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 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]].  


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.  
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 so perfectly approximated by [[19edo]] (4\19), with an error of 0.05 cents, and hence equally well done by the [[enneadecal]] temperament.  
== Approximation ==
It is 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 ==

Revision as of 17:15, 16 November 2021

Interval information
Ratio 81/70
Factorization 2-1 × 34 × 5-1 × 7-1
Monzo [-1 4 -1 -1
Size in cents 252.6804¢
Name septimal ultramajor second
Color name rg2, rugu 2nd
FJS name [math]\displaystyle{ \text{M2}_{35} }[/math]
Special properties reduced
Tenney norm (log2 nd) 12.4691
Weil norm (log2 max(n, d)) 12.6797
Wilson norm (sopfr(nd)) 26

[sound info]
Open this interval in xen-calc

81/70, the 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 temperament targets this progression and uses it as one of the generators.

Approximation

It is perfectly approximated by 19edo (4\19), with an error of 0.05 cents, and hence equally well done by the enneadecal temperament.

See also