Semitone (interval region): Difference between revisions

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{{Wikipedia}}
{{Wikipedia}}
{{About|the [[interval region]]|the interval size unit of exactly 100 cents|Interval size measure#Gross}}
{{About|the [[interval region]]|the interval size unit of exactly 100 cents|Interval size measure#Gross}}
A '''semitone''' is an interval that is near 100 [[cent]]s in size, distinct from [[Comma and diesis|commas and dieses]] (less than 60 cents), and from [[major second]]s (about 200 cents). A rough tuning range for the semitone is about 50 cents to 140 cents, though this is extremely wide; some might prefer to restrict it to around 70 cents to 130 cents.  
A '''semitone''' is an interval that is near 100 [[cent]]s in size, distinct from [[commas and dieses]] (less than 60 cents), and from [[major second]]s (about 200 cents). A rough tuning range for the semitone is about 50 cents to 140 cents, though this is extremely wide; some might prefer to restrict it to around 70 cents to 130 cents.  


Semitones tend to fall into one of two functional categories, based on the system being used:  
Semitones tend to fall into one of two functional categories, based on the system being used:  
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== In just intonation ==
== In just intonation ==
=== By prime limit ===
=== By prime limit ===
In the low prime limits, up to the 5-limit, in which the West has developed a formal system of diatonic harmony, the distinction between diatonic and chromatic semitones is the clearest, so a pair of 2 semitones will be provided for each. However, higher than the 5-limit, function as diatonic vs. chromatic tends to become less clear, and larger intervals can be seen as belonging to neither category.
In the low prime limits, up to the 5-limit, in which the West has developed a formal system of diatonic harmony, the distinction between diatonic and chromatic semitones is the clearest, so a pair of 2 semitones will be provided for each. However, higher than the 5-limit, function as diatonic vs. chromatic tends to become less clear, and larger intervals can be seen as belonging to neither category.


* In the 3-limit:
* In the 3-limit:
** The '''limma,''' or Pythagorean diatonic semitone, is a ratio of 256/243, and is about 90 cents.
** The ''limma'', or ''Pythagorean diatonic semitone'', is a ratio of [[256/243]], and is about 90 cents.
** The '''apotome,''' or Pythagorean chromatic semitone, is a ratio of 2187/2048, and is about 114 cents.
** The ''apotome'', or ''Pythagorean chromatic semitone'', is a ratio of [[2187/2048]], and is about 114 cents.
* In the 5-limit:
* In the 5-limit:
** The '''classical diatonic semitone''' is a ratio of 16/15, and is about 112 cents.
** The ''classical diatonic semitone'' is a ratio of [[16/15]], and is about 112 cents.
** The '''classical chromatic semitone''' is a ratio of 25/24, and is about 71 cents.
** The ''classical chromatic semitone'' is a ratio of [[25/24]], and is about 71 cents.
*** There is also a '''ptolemaic chromatic semitone,''' which is a ratio of 135/128, and is about 92 cents.
*** There is also a ''ptolemaic chromatic semitone'', which is a ratio of [[135/128]], and is about 92 cents.
* In higher limits:
* In higher limits:
** The 7-limit '''third-tone''' is a ratio of 28/27, and is about 63 cents.
** The 7-limit ''third-tone'' is a ratio of [[28/27]], and is about 63 cents.
** The 7-limit '''minor semitone''' is a ratio of 21/20, and is about 84 cents.
** The 7-limit ''minor semitone'' is a ratio of [[21/20]], and is about 84 cents.
** The 7-limit '''major semitone''' is a ratio of 15/14, and is about 119 cents.
** The 7-limit ''major semitone'' is a ratio of [[15/14]], and is about 119 cents.
** The 11-limit '''minor semitone''' is a ratio of 22/21, and is about 81 cents.
** The 11-limit ''minor semitone'' is a ratio of [[22/21]], and is about 81 cents.
** The 13-limit '''sinaic''' is a ratio of 14/13, and is about 128 cents.
** The 13-limit ''sinaic'' is a ratio of [[14/13]], and is about 128 cents.
** The 13-limit '''greater 2/3 tone''' is a ratio of 13/12, and is about 139 cents.
** The 13-limit ''greater 2/3-tone'' is a ratio of [[13/12]], and is about 139 cents.
** The 17-limit '''large semitone''' is a ratio of 17/16, and is about 104 cents.
** The 17-limit ''large semitone'' is a ratio of [[17/16]], and is about 104 cents.
** The 17-limit '''small semitone''' is a ratio of 18/17, and is about 99 cents.
** The 17-limit ''small semitone'' is a ratio of [[18/17]], and is about 99 cents.


=== By delta ===
=== By delta ===
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== In EDOs ==
== In EDOs ==
The following table lists the best tuning of 16/15, 25/24, and other semitones if present, in various significant [[EDOs]].
The following table lists the best tuning of 16/15, 25/24, and other semitones if present, in various significant [[EDO]]s.
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== In regular temperaments ==
== In regular temperaments ==
Two important, simple semitone ratios are 16/15 and 25/24. The following notable temperaments are generated by them:
Two important, simple semitone ratios are 16/15 and 25/24. The following notable temperaments are generated by them:


=== Temperaments that use 25/24 as a generator ===
=== Temperaments that use 25/24 as a generator ===
 
* [[Vishnu]], which stacks seven 25/24s to make a just [[perfect fourth]] of [[4/3]]
* Vishnu, which stacks seven 25/24s to make a just [[perfect fourth]] of [[4/3]]
* [[Chlorine]], equivalent to [[17edo]], stacking seventeen 25/24s to make an octave
* Chlorine, equivalent to [[17edo]], stacking seventeen 25/24s to make an octave


=== Temperaments that use 16/15 as a generator ===
=== Temperaments that use 16/15 as a generator ===
 
{{todo|inline=1|complete list}}
* TBD
 


When 25/24 is tempered out, it leads to [[dicot]] temperament.
When 25/24 is tempered out, it leads to [[dicot]] temperament.


When 16/15 is tempered out, it leads to [[father]] temperament.
When 16/15 is tempered out, it leads to [[father]] temperament.
{{Navbox intervals}}
{{Navbox intervals}}
[[Category:12edo]]
[[Category:12edo]]