225/224

Revision as of 22:49, 7 January 2022 by Godtone (talk | contribs) (added interesting note about 311 EDO being a circle of 225/224's)
Interval information
Ratio 225/224
Factorization 2-5 × 32 × 52 × 7-1
Monzo [-5 2 2 -1
Size in cents 7.711523¢
Names septimal kleisma,
marvel comma
Color name ryy-2, ruyoyo negative 2nd
FJS name [math]\displaystyle{ \text{d}{-2}^{25}_{7} }[/math]
Special properties square superparticular,
reduced
Tenney height (log2 nd) 15.6211
Weil height (log2 max(n, d)) 15.6276
Wilson height (sopfr(nd)) 33
Open this interval in xen-calc

The interval of 225/224, the septimal kleisma or marvel comma is a 7-limit superparticular ratio. It pops up as the difference between pairs of 7-limit ratios, for example as (15/14)/(16/15) or (45/32)/(7/5). It is also the difference between 81/80 and 126/125 and is tempered out alongside these two commas in Septimal meantone. If we don't temper out this interval and instead repeatedly stack (and octave-reduce) it, we get 311edo, where it is equal to 2 steps, meaning 311edo is a circle of 225/224's. Note that this is not true for 226/225 or 224/223, the adjacent superparticulars, as they accumulate too much error to close into a circle in 311edo.

English Wikipedia has an article on:

Temperaments

Tempering out this comma leads to the marvel family of temperaments, which enables marvel chords.

See also