{{Short description|Small musical interval}} thumb|right|Semicomma on C {{audio|Semicomma on C.mid|Play}}.
The '''semicomma''',<ref name="Haluska">Haluska, Jan (2003). ''The Mathematical Theory of Tone Systems'', p.xxix. {{ISBN|80-88683-28-9}}.</ref> also '''Fokker's comma''' (after 31-TET pioneer Adriaan Fokker), is type of small musical interval, or comma, in microtonal music equivalent to 2109375:2097152,<ref name="Haluska"/> or {{nowrap|3<sup>3</sup>×5<sup>7</sup> : 2<sup>21</sup>}}. This is a ratio of approximately 1:1.0058283805847168, or about 10.06 cents<ref>"[http://www.huygens-fokker.org/docs/intervals.html List of Intervals]", ''Huygens-Fokker.org''.</ref> ({{audio|Semicomma on C.mid|Play}}). It is derived from the difference in pitch between three 75:64 just augmented seconds ({{audio|Just augmented second on C.mid|Play just augmented second}}) and one 8:5 just minor sixth ({{audio|Just minor sixth on C.mid|Play minor sixth}}) begun on the same root ((3 × 274.58) − (1 × 813.69) = 823.74 − 813.69 = 10.05 cents).<ref>{{Xenharmonic wiki|Semicomma}}</ref> It can also be viewed as the amount by which three tritaves exceed seven minor sixths.
==See also== *Septimal kleisma *Septimal semicomma
==References== <references/>
{{Intervals|state=expanded}}
Category:5-limit tuning and intervals Category:Commas (music) {{music-theory-stub}}