In music

Music

Music is an art form whose medium is sound and silence. Its common elements are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture...

, septimal diesis (or slendro

Slendro

Slendro is a pentatonic scale, one of the two most common scales used in Indonesian gamelan music, the other being pélog.-Tuning:...

 diesis) is an interval

Interval (music)

In music theory, an interval is a combination of two notes, or the ratio between their frequencies. Two-note combinations are also called dyads...

 with the ratio of 49:48 , which is the difference between the septimal whole tone

Septimal whole tone

In music, the septimal whole tone, septimal major second, or supermajor second is the musical interval exactly or approximately equal to a 8/7 ratio of frequencies. It is about 231 cents wide in just intonation. Although 24 equal temperament does not match this interval particularly well, its...

 and the septimal minor third

Septimal minor third

In music, the septimal minor third , also called the subminor third, is the musical interval exactly or approximately equal to a 7/6 ratio of frequencies. In terms of cents, it is 267 cents, a quartertone of size 36/35 flatter than a just minor third of 6/5...

. It is about 35.7 cents wide, which is narrower than a quarter-tone but wider than the septimal comma

Septimal comma

A septimal comma is a small musical interval in just intonation that contains the number seven in its prime factorization. There is more than one such interval, so the term septimal comma is ambiguous, but it most commonly refers to the interval 64/63....

. It may also be the ratio 36:35, or 48.77 cents.

In equal temperament

In 12 equal temperament this interval is not tempered out; septimal whole tone and septimal minor third are replaced by normal whole tone and minor third. This makes the diesis a semitone, about three times its "correct" size. The septimal diesis is tempered

Musical temperament

In musical tuning, a temperament is a system of tuning which slightly compromises the pure intervals of just intonation in order to meet other requirements of the system. Most instruments in modern Western music are tuned in the equal temperament system...

 out by a number of equally-tempered tuning systems, including 19-ET

19 equal temperament

In music, 19 equal temperament, called 19-TET, 19-EDO, or 19-ET, is the tempered scale derived by dividing the octave into 19 equal steps . Each step represents a frequency ratio of 21/19, or 63.16 cents...

 and 24-ET; these tunings do not distinguish between the septimal whole tone and septimal minor third. It is not tempered out however by 22-ET

22 equal temperament

In music, 22 equal temperament, called 22-tet, 22-edo, or 22-et, is the tempered scale derived by dividing the octave into 22 equal steps . Each step represents a frequency ratio of 21/22, or 54.55 cents ....

 or 31-ET

31 equal temperament

In music, 31 equal temperament, 31-ET, which can also be abbreviated 31-TET, 31-EDO , , is the tempered scale derived by dividing the octave into 31 equal-sized steps...

(or indeed any equal temperament with at least 30 steps).