In
music
Music is generally defined as the art of arranging sound to create some combination of form, harmony, melody, rhythm or otherwise expressive content. Exact definitions of music vary considerably around the world, though it is an aspe ...
, septimal diesis (or
slendro
Slendro ( jv, ꦱ꧀ꦭꦺꦤ꧀ꦢꦿꦺꦴ, ban, slendro, translit=Sléndro) ( su, salendro, translit=Saléndro) is one of the essential tuning systems used in gamelan instruments that have pentatonic scale. Based on Javanese mythology, ...
diesis) is an
interval with the ratio of 49:48 , which is the difference between the
septimal whole tone
In music, the septimal whole tone, septimal major second, or supermajor second is the musical interval exactly or approximately equal to an 8/7 ratio of frequencies.Andrew Horner, Lydia Ayres (2002). ''Cooking with Csound: Woodwind and Brass R ...
and the
septimal minor third
In music, the septimal minor third, also called the subminor third (e.g., by Ellis), 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 ...
. It is about 35.7 cents wide, which is narrower than a
quarter-tone but wider than the
septimal comma. It may also be the ratio 36:35,
or 48.77 cents.
In equal temperament
In
12 equal temperament
Twelve-tone equal temperament (12-TET) is the musical system that divides the octave into 12 parts, all of which are equally tempered (equally spaced) on a logarithmic scale, with a ratio equal to the 12th root of 2 ( ≈ 1.05946). That resultin ...
this interval is not tempered out; the
septimal whole tone and septimal minor third are replaced by the normal whole tone and minor third. This makes the diesis a semitone, about twice its "correct" size. The septimal diesis is
tempered out by a number of equally tempered tuning systems, including
19-ET,
24-ET and
29-ET; these tunings do not distinguish between the septimal whole tone and septimal minor third. It is not tempered out however by
22-ET or
31-ET (or indeed any equal temperament with at least 30 steps).
See also
*
Diesis
References
{{Intervals, state=expanded
Commas (music)
0049:0048
7-limit tuning and intervals