3645/3584

Revision as of 19:27, 26 July 2026 by Godtone (talk | contribs) (add etymology section, propose alternate name that feels less awkward than current name, link, note connection to septimal meantone)

The tritonic diesis[idiosyncratic term] or schismean comma[idiosyncratic term] (monzo: [-9 6 1 -1, ratio: 3645/3584) is a small 7-limit comma measuring about 29.2 cents.

Interval information
Ratio 3645/3584
Factorization 2-9 × 36 × 5 × 7-1
Monzo [-9 6 1 -1
Size in cents 29.21781¢
Names tritonic diesis[idiosyncratic term],
schismean comma[idiosyncratic term]
Color name Lry-2, Laruyo negative 2nd
FJS name [math]\displaystyle{ \text{d}{-2}^{5}_{7} }[/math]
Special properties reduced
Tenney norm (log2 nd) 23.6391
Weil norm (log2 max(n, d)) 23.6634
Wilson norm (sopfr(nd)) 48
Comma size small
Open this interval in xen-calc

It is the difference between three major whole tones and a small septimal tritone, or in other words, (9/8)3/(7/5).

Temperaments

It is most notably and characteristically tempered out in septimal meantone, where 7/5 is an augmented fourth, as the flat fifth of meantone helps motivate this equivalence.

Tempering out this comma leads to the rank-3 schismean temperament. Other rank-2 temperaments which temper out this comma include schism and pycnic.

Etymology

The name schismean was given by Xenllium in 2022, most likely as a contraction of schism and meantone. The name tritonic diesis was given later in 2026 by the observation of Godtone that it fit a general algorithmic definition discussed in Diesis#Generalization, combined with the observation that the septimal tritonic diesis of (10/7)/(7/5) = 50/49 seemed to suggest the existence of a tritonic diesis with a focus on the tritone part as contrasted to the septimal part, hence the expression of it as the amount by which the "literal" tritone (9/8)3 exceeds the LCJI tritone 7/5.