121/120

Interval information

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
FJS name	[math]\displaystyle{ \text{d1}^{11,11}_{5} }[/math]
Special properties	square superparticular, reduced
Tenney norm (log2 nd)	13.8258
Weil norm (log2 max(n, d))	13.8377
Wilson norm (sopfr(nd))	36
Comma size	small
S-expression	S11
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In just intonation, 121/120, otherwise known as the biyatisma, or undecimal seconds comma, is a superparticular interval of around 14.4¢ which makes the difference between two undecimal neutral seconds of 11/10 and 12/11. Equal temperaments in which 121/120 is tempered out include 15, 22, 29, 31, 46, 53 and others; in such systems, 11/10 and 12/11 are equated. 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. Along with being the difference between 11/10 and 12/11, 121/120 is the difference between 11/8 and 15/11, so that tempering out 121/120 allows for the dyadic triad which has intervals of 11/8, 11/8, and 16/15 (biyatismic chords).

See also

• Biyatismic chords
• Rank-4 temperament #Biyatismic (121/120)
• Biyatismic clan, the clan of rank-3 temperaments where it is tempered out
• Small comma
• List of superparticular intervals