243/242

Interval information

Ratio

243/242

Factorization

2^-1 × 3⁵ × 11^-2

Monzo

[-1 5 0 0 -2⟩

Size in cents

7.13912¢

Names

rastma,
neutral third comma

FJS name

[math]\displaystyle{ \text{A1}_{121} }[/math]

Special properties

superparticular,
reduced

Tenney height (log₂ nd)

15.8437

Weil height (log₂ max(n, d))

15.8496

Wilson height (sopfr(nd))

39

Open this interval in xen-calc

243/242, the rastma or the neutral third comma, is an 11-limit (also 2.3.11 subgroup) comma with a value of roughly 7.1 cents. It is significant in Just Intonation as the amount by which a stack of two 33/32 quartertones falls short of an apotome (2187/2048) as well as the difference between 11/9 and 27/22, and, the difference between 45/44 and 55/54. The last makes the theory where the rastma serves as the subchroma that separates greater and lesser 11-limit chromas – a property that becomes especially apparent when one works extensively with the 11-limit.

Temperament

Tempering it out leads to a form of rastmic temperament, or in the 2.3.11 subgroup, the neutral temperament, enabling rastmic chords.

243/242

Temperament

See also