2187/2048: Difference between revisions

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m a large comma
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added a less jargon-y and more musical name for 2187/2048
 
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{{Infobox Interval
{{Infobox Interval
| Ratio = 2187/2048
| Name = apotome, Pythagorean chroma, Pythagorean chromatic semitone, whitewood comma
| Monzo = -11 7
| Color name = Lw1, lawa unison
| Cents = 113.6850
| Name = Apotome, <br>Pythagorean chromatic semitone
| Sound = jid_2187_2048_pluck_adu_dr220.mp3
| Sound = jid_2187_2048_pluck_adu_dr220.mp3
| FJS name = A1
| Comma = yes
}}
}}
{{Wikipedia|Semitone#Pythagorean tuning}}


The '''apotome''', also known as the '''Pythagorean chromatic semitone''' or the '''Pythagorean major semitone''', is the interval 3<sup>7</sup>/2<sup>11</sup> = 2187/2048 which is the chromatic semitone in the [[Pythagorean tuning|Pythagorean]] ([[3-limit]]) version of the diatonic scale. 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]]. It measures about 113.and can be generated by stacking seven [[3/2]] perfect fifths and octave-reducing the resulting interval.
'''2187/2048''', the '''apotome''' (pronounced /əˈpɒtəmi/, like "a-POT-o'-me"), also known as the '''Pythagorean chromatic semitone''' or the '''Pythagorean chroma''' or the '''3-limit augmented unison''', 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]].
 
== Approximation ==
This interval is well approximated by any tuning generated with accurate octaves and fifths. For example, [[53edo|5\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.
 
== Notation ==
The apotome is the interval by which a sharp (#) or flat (b) modifies a note in the [[5L 2s|diatonic]] [[chain-of-fifths notation]]. For example, in Pythagorean tuning, C and C# in the same octave are exactly an apotome apart. In tempered tuning systems, the mapping of the apotome dictates the size of sharps and flats. For instance, if the apotome is [[tempered out]], then sharps and flats have no effect on pitch in these systems.
 
The number of steps an apotome is mapped to in an EDO is referred to as its [[sharpness]].
 
== Etymology ==
According to the OED, the earliest English use of [[limma]] and apotome (alt. spelling "apotomy") with its musical as opposed to mathematical<ref>https://www.scientificlib.com/en/Mathematics/LX/Apotome.html</ref> meaning, is in 1694 in ''A Treatise of the Natural Grounds and Principles of Harmony''<ref>https://ota.bodleian.ox.ac.uk/repository/xmlui/bitstream/handle/20.500.12024/A44132/A44132.html</ref> by Church of England clergyman and natural philosopher William Holder. A relevant quote is "Difference between ... Tone Maj. and Limma. Apotome 2187 to 2048". The words are formed from the Greek, with "apo" meaning "away", "tome" meaning "cut" and limma meaning "remnant". So we begin with a major whole tone; the part cut away is the apotome (chromatic semitone) and the remnant is the limma (diatonic semitone).


== See also ==
== See also ==
* [[Gallery of Just Intervals]]
* [[4096/2187]] – its [[octave complement]]
* [[Large commas]]
* [[Gallery of just intervals]]
* [[Large comma]]
* [[25/24]] – classic chromatic semitone
 
== References ==


[[Category: 3-limit]]
[[Category:Second]]
[[Category: Large comma]]
[[Category:Semitone]]
[[Category: Interval]]
[[Category:Chroma]]
[[Category: Interval ratio]]
[[Category:Whitewood]]
[[Category: Pythagorean]]
[[Category: Semitone]]