25/24: Difference between revisions

From Xenharmonic Wiki
Jump to navigation Jump to search
No edit summary
-27/25 vs 9/8: not a difference between HC5 interval
Line 5: Line 5:
| Comma = yes
| Comma = yes
}}
}}
 
'''25/24''', the '''just chromatic semitone''', '''classic(al) chromatic semitone''' or '''diptolemaic chromatic semitone''', 70.672{{cent}}, is the [[superparticular]] ratio which marks the difference between the [[5-limit]] seconds, [[16/15]] and [[10/9]], thirds, [[6/5]] and [[5/4]], sixths, [[8/5]] and [[5/3]], and sevenths, [[9/5]] and [[15/8]]. It is therefore the amount which sharpens or flattens a 5-limit second, third, sixth, or seventh, and when notating 5-limit just intonation it can be associated with the sharp or flat symbol, and along with an additional symbol for the [[81/80]] comma, it can be used for a complete system of [[5-limit]] notation as an extension of diatonic.
'''25/24''', the '''just chromatic semitone''', '''classic(al) chromatic semitone''' or '''diptolemaic chromatic semitone''', 70.672{{cent}}, is the [[superparticular]] ratio which marks the difference between the [[5-limit]] seconds, [[16/15]] and [[10/9]], [[27/25]] and [[9/8]], thirds, [[6/5]] and [[5/4]], sixths, [[8/5]] and [[5/3]], and sevenths, [[16/9]] and [[50/27]], and [[9/5]] and [[15/8]] . It is therefore the amount which sharpens or flattens a 5-limit second, third, sixth, or seventh, and when notating 5-limit just intonation it can be associated with the sharp or flat symbol, and along with an additional symbol for the [[81/80]] comma, it can be used for a complete system of [[5-limit]] notation as an extension of diatonic.


== Approximation ==
== Approximation ==
Line 22: Line 21:
* [[Medium comma]]
* [[Medium comma]]
* [[List of superparticular intervals]]
* [[List of superparticular intervals]]
* [[Chromatic semitone]] – a generalising concept for the [[diatonic]] scale
* [[Chromatic semitone]] – a generalising concept for the [[5L 2s|diatonic]] scale
* [[Chroma]] – a generalising concept for all [[mos]] scales
* [[Chroma]] – a generalising concept for all [[mos]] scales



Revision as of 13:47, 16 April 2025

Interval information
Ratio 25/24
Factorization 2-3 × 3-1 × 52
Monzo [-3 -1 2
Size in cents 70.67243¢
Names just chromatic semitone,
classic(al) chromatic semitone,
diptolemaic chromatic semitone,
dicot comma
Color name yy1, yoyo unison
FJS name [math]\displaystyle{ \text{A1}^{5,5} }[/math]
Special properties square superparticular,
reduced
Tenney norm (log2 nd) 9.22882
Weil norm (log2 max(n, d)) 9.28771
Wilson norm (sopfr(nd)) 19
Comma size medium
S-expression S5

[sound info]
Open this interval in xen-calc

25/24, the just chromatic semitone, classic(al) chromatic semitone or diptolemaic chromatic semitone, 70.672 ¢, is the superparticular ratio which marks the difference between the 5-limit seconds, 16/15 and 10/9, thirds, 6/5 and 5/4, sixths, 8/5 and 5/3, and sevenths, 9/5 and 15/8. It is therefore the amount which sharpens or flattens a 5-limit second, third, sixth, or seventh, and when notating 5-limit just intonation it can be associated with the sharp or flat symbol, and along with an additional symbol for the 81/80 comma, it can be used for a complete system of 5-limit notation as an extension of diatonic.

Approximation

25/24 is very accurately approximated by 17edo's 1\17 (70.588 ¢). In fact, the interval that results from stacking seventeen 25/24 chromatic semitones reduced by an octave is the septendecima, only 1.428 ¢ in size.

Temperaments

If 25/24 is treated as a comma to be tempered out, it may be called the dicot comma. Doing so leads to the dicot temperament, where the distinction between major and minor thirds are removed and there is only a single neutral interval functioning as both, as in 7edo and 10edo. See dicot family for the rank-2 family where it is tempered out.

See also