20/19

Interval information
Ratio	20/19
Subgroup monzo	2.5.19 [2 1 -1⟩
Size in cents	88.800698¢
Names	small undevicesimal semitone, undevicesimal chroma, Eratosthenes' semitone
Color name	19uy1, nuyo unison
FJS name	[math]\text{A1}^{5}_{19}[/math]
Special properties	superparticular, reduced
Tenney height (log₂ nd)	8.56986
Weil height (log₂ max(n, d))	8.64386
Wilson height (sopfr (nd))	28
Harmonic entropy (Shannon, [math]\sqrt{n\cdot d}[/math])	~4.66443 bits
Comma size	medium
[sound info]
open this interval in xen-calc

In 19-limit just intonation, 20/19 is the small undevicesimal semitone or Eratosthenes' semitone, measuring about 88.8 ¢. It is flat of the Pythagorean limma (256/243) by 1216/1215, the password aka Eratosthenes' comma.

It is almost exactly 1/3 of a subminor third of 7/6. The small comma (7/6)/(20/19)³ = 48013/48000 is tempered out in 12, 41, 53, 68, 80, 94, 121, 161, 190, 202, 217, 229, 243, 270, 282, 311, 323, 364, 460, 472, 513, 525, 540, 581, 742, 783, 795, 1012, 1053, 1106, 1308, 1323, 1578, 1848, 1889, and 2320 EDOs, leading to a variety of temperaments in which three semitones make up a subminor third.

It is very close to 2 steps out of 27edo, or 88.8889 ¢.

See also