256/243: Difference between revisions

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{{Infobox Interval
{{Infobox Interval
| Name = Pythagorean limma, Pythagorean diatonic semitone, 3-limit minor 2nd, blackwood comma
| 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
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{{Wikipedia| Semitone #Pythagorean tuning }}
{{Wikipedia| Semitone #Pythagorean tuning }}


The interval '''256/243''', the '''Pythagorean limma''' or '''Pythagorean diatonic semitone''' or the '''3-limit minor 2nd''' 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, or equivalently by decreasing 4/3 by two [[9/8]] major seconds.
'''256/243''', the '''Pythagorean limma''' or '''Pythagorean diatonic semitone''', is the [[diatonic semitone]] in [[Pythagorean tuning]]. In other words, it is the [[3-limit]] minor second. It factors as 2<sup>8</sup>/3<sup>5</sup>, and is about 90.2 [[cent]]s in size. It can be generated by stacking five [[4/3]] just perfect fourths and [[octave reduction|octave-reducing]] the resulting interval, or equivalently by decreasing 4/3 by two [[9/8]] major seconds. Unlike the situation in [[meantone]] tunings, it is smaller, not larger, than the corresponding [[chromatic semitone]], which is the Pythagorean augmented unison of [[2187/2048]].  


== Approximation ==
== Approximation ==
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== Temperaments ==
== 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''', named after [[Easley Blackwood Jr]]. 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.
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''', named after [[Easley Blackwood Jr]]. 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.


== Notation ==
== Notation ==