256/243: Difference between revisions

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added color name
+"blackwood comma"; expand on approximation
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{{Infobox Interval
{{Infobox Interval
| Name = Pythagorean limma, Pythagorean diatonic semitone
| Name = Pythagorean limma, Pythagorean diatonic semitone, blackwood comma
| Color name = sw2, sawa 2nd
| Color name = sw2, sawa 2nd
| Sound = jid_256_243_pluck_adu_dr220.mp3
| Sound = jid_256_243_pluck_adu_dr220.mp3
| Comma = yes
| Comma = yes
}}
}}
{{Wikipedia|Semitone#Pythagorean tuning}}
{{Wikipedia| Semitone #Pythagorean tuning }}


The interval '''256/243''', the '''Pythagorean limma''', or '''Pythagorean diatonic semitone''' factors as 2<sup>8</sup>/3<sup>5</sup>, is about 90.2 [[cent]]s in size, and is the diatonic semitone in [[Pythagorean tuning]]. It can be generated by stacking five [[4/3]] just perfect fourths and [[Octave reduction|octave-reducing]] the resulting interval.
The interval '''256/243''', the '''Pythagorean limma''', or '''Pythagorean diatonic semitone''' factors as 2<sup>8</sup>/3<sup>5</sup>, is about 90.2 [[cent]]s in size, and is the diatonic semitone in [[Pythagorean tuning]]. It can be generated by stacking five [[4/3]] just perfect fourths and [[Octave reduction|octave-reducing]] the resulting interval.


== Approximation ==
== Approximation ==
[[53edo|4\53]] is a very good approximation of the interval.  
This interval is well approximated by any tuning generated with accurate octaves and fifths. For example, [[53edo|4\53]] is a very good approximation.  


== Temperament ==
== Temperaments ==
When this ratio is taken as a comma to be tempered (and the starting [[JI subgroup]] is the [[5-limit]]), it produces [[blackwood]] temperament. Edos tempering it out include [[5edo]], [[10edo]], [[15edo]], [[20edo]], [[25edo]] and [[30edo]].
When this ratio is taken as a comma to be tempered in the [[5-limit]], it produces the [[blackwood]] temperament, and it may be called the '''blackwood comma'''. Edos tempering it out include [[5edo]], [[10edo]], [[15edo]], [[20edo]], [[25edo]] and [[30edo]]. See [[limmic temperaments]] for a number of other temperaments where it is tempered out.  


== See also ==
== See also ==
* [[243/128]] – its [[octave complement]]
* [[243/128]] – its [[octave complement]]
* [[729/512]] – its [[fifth complement]]
* [[729/512]] – its [[fifth complement]]
* [[16/15]] - the classic (5-limit) diatonic semitone
* [[16/15]] the classic (5-limit) diatonic semitone
* [[Gallery of just intervals]]
* [[Gallery of just intervals]]
* [[Limma family]], where it is tempered out
* [[Medium comma]]
* [[Medium comma]]
* [[Pythagorean tuning]]
* [[Pythagorean tuning]]
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[[Category:Second]]
[[Category:Second]]
[[Category:Semitone]]
[[Category:Semitone]]
[[Category:Blackwood]]

Revision as of 09:38, 21 December 2022

Interval information
Ratio 256/243
Factorization 28 × 3-5
Monzo [8 -5
Size in cents 90.225¢
Names Pythagorean limma,
Pythagorean diatonic semitone,
blackwood comma
Color name sw2, sawa 2nd
FJS name [math]\displaystyle{ \text{m2} }[/math]
Special properties reduced,
reduced subharmonic
Tenney norm (log2 nd) 15.9248
Weil norm (log2 max(n, d)) 16
Wilson norm (sopfr(nd)) 31
Comma size medium
S-expression S7⋅S82

[sound info]
Open this interval in xen-calc
English Wikipedia has an article on:

The interval 256/243, the Pythagorean limma, or Pythagorean diatonic semitone factors as 28/35, is about 90.2 cents in size, and is the diatonic semitone in Pythagorean tuning. It can be generated by stacking five 4/3 just perfect fourths and octave-reducing the resulting interval.

Approximation

This interval is well approximated by any tuning generated with accurate octaves and fifths. For example, 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 blackwood temperament, and it may be called the blackwood comma. Edos tempering it out include 5edo, 10edo, 15edo, 20edo, 25edo and 30edo. See limmic temperaments for a number of other temperaments where it is tempered out.

See also