28/27
Interval information |
septimal third-tone,
subminor second,
septimal minor second
reduced
[sound info]
The superparticular interval 28/27 (also septimal chroma or septimal third-tone) has the seventh triangular number as a numerator and is the difference between 15/14 and 10/9, 9/8 and 7/6, 9/7 and 4/3, 3/2 and 14/9, 12/7 and 16/9, and 9/5 and 28/15.
If treated as an interval in its own right, it may be described as the septimal subminor second, since it differs from the Pythagorean minor second 256/243 by 64/63, and from 16/15 by 36/35. This is analogous to the septimal major second 8/7, which has the same relationship with 9/8 and 10/9, respectively. Such classification suggests the function of a strong leading tone added to the traditional harmony.