81/70: Difference between revisions

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'''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 subminor third [[7/6]] by a sensamagic comma [[245/243]], and sharp of a major second [[16/9]] by a septimal quartertone [[36/35]].  
'''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 subminor third [[7/6]] by a sensamagic comma [[245/243]], and sharp of a major second [[16/9]] by a septimal quartertone [[36/35]].  


It is also sharp 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.  
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.  


The interval is so perfectly approximated by [[19edo|19-edo]], with an error of 0.05 cents. There are a number of edos that do this equally well, [[171edo|171-edo]] to name one. The first edo that does this better than 19-edo with patent val is [[660edo|660-edo]].  
The interval is so perfectly approximated by [[19edo]], with an error of 0.05 cents. There are a number of edos that do this equally well, [[171edo]] to name one. The first edo that does this better than 19edo with patent val is [[660edo]].  


== See also ==
== See also ==

Revision as of 08:44, 2 October 2020

Interval information
Ratio 81/70
Factorization 2-1 × 34 × 5-1 × 7-1
Monzo [-1 4 -1 -1
Size in cents 252.6804¢
Names septimal semiaugmented second,
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 semiaugmented second or septimal ultramajor second is a 7-limit interseptimal ratio of about 253 cents. It is sharp of a subminor third 7/6 by a sensamagic comma 245/243, and sharp of a major second 16/9 by a septimal quartertone 36/35.

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 temperament targets this progression and uses it as one of the generators.

The interval is so perfectly approximated by 19edo, with an error of 0.05 cents. There are a number of edos that do this equally well, 171edo to name one. The first edo that does this better than 19edo with patent val is 660edo.

See also