Cataharry comma

Revision as of 19:22, 6 June 2021 by Aura (talk | contribs) (placed a link for "fourth complement", as this concept will hopefully be fleshed out)
Interval information
Ratio 19683/19600
Factorization 2-4 × 39 × 5-2 × 7-2
Monzo [-4 9 -2 -2
Size in cents 7.315767¢
Name cataharry comma
FJS name [math]\displaystyle{ \text{m}{-2}_{5,5,7,7} }[/math]
Special properties reduced
Tenney height (log2 nd) 28.5232
Weil height (log2 max(n, d)) 28.5293
Wilson height (sopfr(nd)) 59
Open this interval in xen-calc

The cataharry comma (19683/19600) is a 7-limit comma measuring about 6.1 cents. It is the difference between the septimal ultramajor second (81/70) and its fourth complement. In terms of commas, it is the difference between 81/80 and 245/243.

Temperaments

Tempering out this comma leads to the rank-3 cataharry family of temperaments, which splits the just perfect fourth (4/3) into two exact hemifourths, each representing 81/70~280/243.

See also