# 121/120

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 Ratio 121/120 Factorization 2-3 × 3-1 × 5-1 × 112 Monzo [-3 -1 -1 0 2⟩ Size in cents 14.36717¢ Names biyatisma,undecimal seconds comma Color name 1oog1, lologu 1sn,Lologu comma FJS name $\text{d1}^{11,11}_{5}$ Special properties square superparticular,reduced Tenney height (log2 nd) 13.8258 Weil height (log2 max(n, d)) 13.8377 Wilson height (sopfr (nd)) 36 Harmonic entropy(Shannon, $\sqrt{n\cdot d}$) ~3.16917 bits Comma size small S-expression S11 open this interval in xen-calc

In just intonation, 121/120, otherwise known as the biyatisma, or undecimal seconds comma, is a superparticular interval of around 14.4 cents which makes the difference between two undecimal neutral seconds of 11/10 and 12/11, as well as between 11/8 and 15/11.

## Temperaments

Tempering out this comma in the 11-limit gives the rank-4 biyatismic temperament (→ Rank-4 temperament #Biyatismic (121/120)). Tempering it out in the 2.3.5.11 subgroup gives the rank-3 protomere temperament. See biyatismic clan for extensions of protomere. In such systems, 11/10 and 12/11 are equated, enabling biyatismic chords. This is in contrast to the more familiar tempering out of 81/80, which results in meantone and other temperaments, in which 10/9 is equated with 9/8. Equal temperaments in which 121/120 is tempered out include 15, 22, 29, 31, 46, 53 and others.

## Etymology

The biyatisma was presumably named by Gene Ward Smith in 2010 since it seems this wiki was the place where it made its first appearance[1]. The name seems to come from maqam bayati, which features a neutral second. It is yet to be found out why it is spelt with an "i" instead of an "a".