2187/2048: Difference between revisions

TallKite (talk | contribs)
added color name
Never seen "Pythagorean major chroma" attested, replaced with Pythagorean chroma; +"whitewood comma"; +approximation
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{{Infobox Interval
{{Infobox Interval
| Name = apotome, Pythagorean chromatic semitone
| Name = apotome, Pythagorean chroma, Pythagorean chromatic semitone, whitewood comma
| Color name = Lw1, lawa unison
| Color name = Lw1, lawa unison
| Sound = jid_2187_2048_pluck_adu_dr220.mp3
| Sound = jid_2187_2048_pluck_adu_dr220.mp3
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{{Wikipedia|Semitone#Pythagorean tuning}}
{{Wikipedia|Semitone#Pythagorean tuning}}


'''2187/2048''', the '''apotome''', also known as the '''Pythagorean chromatic semitone''' or the '''Pythagorean major semitone''', is the chromatic semitone in the [[Pythagorean tuning]]. It is the [[3-limit]] interval between seven perfect just fifths ([[3/2]]) and four octaves ([[2/1]]): 3<sup>7</sup>/2<sup>11</sup> = 2187/2048, and measures about 113.7¢. Unlike the situation in [[meantone]] tunings, it is larger, not smaller, than the corresponding diatonic semitone, which is the Pythagorean minor second of [[256/243]].
'''2187/2048''', the '''apotome''', also known as the '''Pythagorean chromatic semitone''' or the '''Pythagorean chroma''', is the [[chromatic semitone]] in the [[Pythagorean tuning]]. It is the [[3-limit]] interval between seven perfect just fifths ([[3/2]]) and four octaves ([[2/1]]): 3<sup>7</sup>/2<sup>11</sup> = 2187/2048, and measures about 113.7¢. Unlike the situation in [[meantone]] tunings, it is larger, not smaller, than the corresponding diatonic semitone, which is the Pythagorean minor second of [[256/243]].


== Temperament ==
== Approximation ==
When treated as a comma to be tempered out, it leads to [[apotome family]] of temperaments.  
This interval is well approximated by any tuning generated with accurate octaves and fifths. For example, [[53edo|4\53]] is a very good approximation.
 
== Temperaments ==
When this ratio is taken as a comma to be tempered in the 5-limit, it produces the [[whitewood]] temperament, and it may be called the '''whitewood comma'''. See [[apotome family]] for extensions thereof.  


== See also ==
== See also ==
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* [[Gallery of just intervals]]
* [[Gallery of just intervals]]
* [[Large comma]]
* [[Large comma]]
* [[53edo|5\53]] is a very good approximation of the interval
* [[25/24]] – classic chromatic semitone
* [[25/24]] – classic chromatic semitone


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[[Category:Semitone]]
[[Category:Semitone]]
[[Category:Chroma]]
[[Category:Chroma]]
[[Category:Apotomic]]
[[Category:Whitewood]]