25/24

Interval information

Ratio

25/24

Factorization

2^-3 × 3^-1 × 5²

Monzo

[-3 -1 2⟩

Size in cents

70.67243¢

Names

classic chromatic semitone,
chroma

FJS name

[math]\displaystyle{ \text{A1}^{25} }[/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

[sound info]

Open this interval in xen-calc

The classic chromatic semitone (short: chroma), 25/24, 70.672 cents, is the superparticular ratio which marks the difference between the 5-limit thirds, 6/5 and 5/4, and sixths, 8/5 and 5/3. It is therefore the amount which sharpens or flattens a 5-limit third or sixth, 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.

It 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 it is treated as a comma to be tempered out, you remove the distinction between major and minor thirds and get only a single neutral interval in their place as in dicot family, and edos like 10edo or 17edo.

25/24

Temperaments

See also