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{{Infobox Interval
{{Infobox Interval
| Ratio = 2109375/2097152
| Ratio = 2109375/2097152
| Name = semicomma, Fokker comma
| Name = semicomma, orson comma, Fokker's comma
| Color name = Ly<sup>7</sup>-3, Lasepyo comma
| Color name = Ly<sup>7</sup>-3, Lasepyo comma
| Comma = yes
| Comma = yes
}}
}}
The '''semicomma''' or '''Fokker comma''' ([[ratio]]: 2109375/2097152, [[monzo]]: {{monzo| -21 3 7 }}), is an interval of 10.061 [[cent]]s which is the amount by which three classic augmented second intervals of [[75/64]] exceed [[8/5]]. That means (75/64)<sup>3</sup>/(8/5), which can also be written ((9/8)(25/24))<sup>3</sup>/(8/5). In terms of commas, it factors into simpler commas as ([[15625/15552]])([[32805/32768]]), the kleisma and the schisma. Tempering it out leads to [[orson]] temperament.  
{{Wikipedia}}
The '''semicomma''' or '''Fokker's comma''' ([[ratio]]: 2109375/2097152, [[monzo]]: {{monzo| -21 3 7 }}), is a [[small comma|small]] [[5-limit]] [[comma]] of 10.061 [[cent]]s which is the amount by which three classic augmented second intervals of [[75/64]] exceed [[8/5]]. That means (75/64)<sup>3</sup>/(8/5), which can also be written ((9/8)(25/24))<sup>3</sup>/(8/5). In terms of commas, it factors into simpler commas as ([[15625/15552]])([[32805/32768]]), the kleisma and the schisma. It is also the difference between the [[31-comma]] ({{nowrap|3<sup>31</sup>/2<sup>49</sup>}}) and seven syntonic commas ([[81/80]]).
 
== Temperaments ==
[[Tempering out]] this comma in the 5-limit leads to the [[orson]] temperament.
 
== Etymology ==
Given the other intervals called "semicomma", it is likely that "semicomma" refers to the comma's size as about half the size of the syntonic comma. The name "semicomma" was given by [[Adriaan Fokker]], while the name "Fokker's comma" refers to him directly and was likely proposed later.


== See also ==
== See also ==
Intervals with the word "semicomma" in the name:
* [[126/125]] (aka starling comma or septimal semicomma)
* Medium semicomma, aka [[sensipent comma]]
* [[15625/15552]] (aka kleisma or semicomma majeur)
* Septimal semicomma, aka [[126/125|starling comma]]
* [[Sensipent comma]] (78732/78125, aka medium semicomma)
* Semicomma majeur, aka [[15625/15552|kleisma]]
 
== External links ==
* [http://tonalsoft.com/enc/s/semicomma.aspx Semicomma] on [[Tonalsoft Encyclopedia]]


[[Category:Orson]]
[[Category:Orson]]
[[Category:Commas with unknown etymology]]
[[Category:Commas named after composers]]
[[Category:Commas named after music theorists]]
{{Todo|research|comment=Explain the reasoning behind the name "semicomma". Why is 2109375/2097152 uniquely deserving of the name?}}

Latest revision as of 21:05, 15 July 2026

Interval information
Ratio 2109375/2097152
Factorization 2-21 × 33 × 57
Monzo [-21 3 7
Size in cents 10.061¢
Names semicomma,
orson comma,
Fokker's comma
Color name Ly7-3, Lasepyo comma
FJS name [math]\displaystyle{ \text{dddd}{-3}^{5,5,5,5,5,5,5} }[/math]
Special properties reduced,
reduced harmonic
Tenney norm (log2 nd) 42.0084
Weil norm (log2 max(n, d)) 42.0168
Wilson norm (sopfr(nd)) 86
Comma size small
Open this interval in xen-calc
English Wikipedia has an article on:

The semicomma or Fokker's comma (ratio: 2109375/2097152, monzo: [-21 3 7), is a small 5-limit comma of 10.061 cents which is the amount by which three classic augmented second intervals of 75/64 exceed 8/5. That means (75/64)3/(8/5), which can also be written ((9/8)(25/24))3/(8/5). In terms of commas, it factors into simpler commas as (15625/15552)(32805/32768), the kleisma and the schisma. It is also the difference between the 31-comma (331/249) and seven syntonic commas (81/80).

Temperaments

Tempering out this comma in the 5-limit leads to the orson temperament.

Etymology

Given the other intervals called "semicomma", it is likely that "semicomma" refers to the comma's size as about half the size of the syntonic comma. The name "semicomma" was given by Adriaan Fokker, while the name "Fokker's comma" refers to him directly and was likely proposed later.

See also

External links