15/14

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Interval information
Ratio 15/14
Factorization 2-1 × 3 × 5 × 7-1
Monzo [-1 1 1 -1
Size in cents 119.44281¢
Names septimal diatonic semitone,
septimal major semitone
Color name ry1, ruyo unison
FJS name [math]\text{A1}^{5}_{7}[/math]
Special properties superparticular,
reduced
Tenney height (log2 nd) 7.71425
Weil height (log2 max(n, d)) 7.81378
Wilson height (sopfr (nd)) 17
Harmonic entropy
(Shannon, [math]\sqrt{n\cdot d}[/math])
~4.623 bits

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

15/14 is a superparticular ratio with a numerator which is the fifth triangular number. It may be found as the interval between many 7-limit ratios, including:

In combination with 19/17 it forms a good approximation of golden meantone. The untempered combination of five 19/17 and two 15/14 leads to an interval that is sharp to an octave by the mercurial comma: ((19/17)^5 * (15/14)^2 = (2/1) / (mercurial comma))

Terminology

15/14 is traditionally called a diatonic semitone, perhaps for its proximity (and conflation in systems such as septimal meantone) with the classic diatonic semitone 16/15. However, 15/14 is a chromatic semitone in both Helmholtz-Ellis notation and Functional Just System, viewed as the apotome 2187/2048 altered by 5120/5103. Marc Sabat has taken to call it the major chromatic semitone in the same material where 21/20 is also named as the minor diatonic semitone[1].

Approximation

15/14 is very accurately approximated by 10EDO (1\10) and all linus temperaments. The linus comma, 5.6¢, is the amount by which a stack of ten 15/14's falls short of the octave.

References

See also