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Interval information
Ratio 49/48
Factorization 2-4 × 3-1 × 72
Monzo [-4 -1 0 2
Size in cents 35.696812¢
Names large septimal diesis,
slendro diesis,
semaphore comma
Color name zz2, zozo 2nd,
Zozo comma
FJS name [math]\text{m2}^{7,7}[/math]
Special properties square superparticular,
Tenney height (log2 nd) 11.1997
Weil height (log2 max(n, d)) 11.2294
Wilson height (sopfr (nd)) 25
Harmonic entropy
(Shannon, [math]\sqrt{nd}[/math])
~4.52118 bits
Comma size medium
S-expression S7

[sound info]
open this interval in xen-calc
English Wikipedia has an article on:

49/48, the large septimal diesis (or slendro diesis), is a superparticular ratio spanning the small distance between a subminor third (7/6) and a supermajor second (8/7) or between the supermajor sixth (12/7) and the harmonic seventh (7/4). Measuring about 35.7 ¢, it is a medium comma; however, in classical Western music, this interval is not known as a comma as it is not tempered out in 12edo.


49/48 is tempered out in 15edo and 19edo, where the two intervals are equated, and the fourth is split in a perfect half. In the 2.3.7 subgroup, this is known as the semaphore temperament, and the comma is thus known as the semaphore comma. It cannot be tempered out if all of the consonances of the 7-odd-limit are distinct, but it can be equated with other commas; for example (49/48)/(81/80) = 245/243, (49/48)/(64/63) = 1029/1024, (49/48)/(3125/3072) = 3136/3125, (49/48)/(50/49) = 2401/2400, (128/125)/(49/48) = 6144/6125, (36/35)/(49/48) = 1728/1715.

See also