20480/19683: Difference between revisions

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Added a page for the superpyth comma
 
Sectioning. Linking. - 17edo in favor of 49edo. + category
 
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{{Infobox Interval|Name=superpyth comma|Color name=sayo 2nd, sayo comma}}
{{Infobox Interval
| Name = retroptolemaic minor second, superpyth comma
| Color name = sayo 2nd, sy2, Sayo comma
}}
'''20480/19683''', the '''retroptolemaic minor second''', is a [[5-limit]] [[interval]] measuring about 68.7{{cent}}. It gets its name from being equal to being one [[81/80|syntonic comma (81/80)]] flatter than the [[256/243|Pythagorean limma (256/243)]], in contrast to [[16/15]] which is a syntonic comma ''sharper'' than a Pythagorean limma.


20480/19683, the superpyth comma, is the difference between 5/4 and an [[Octave reduction|octave-reduced]] stack of nine 3/2s, as well as 25/24 minus a [[schisma]] (32805/32768). Tempering it out by itself defines the 5-limit version of [[superpyth]] temperament. Notable [[EDO|EDOs]] that temper it out include [[17edo|17]], [[22edo|22]], and [[27edo|27]].
== Temperaments ==
When treated as a [[comma]] to be [[tempering out|tempered out]], it is the '''superpyth comma''', and is the difference between [[5/4]] and an [[octave reduction|octave-reduced]] stack of nine [[3/2]]'s, as well as [[25/24]] minus a [[schisma|schisma (32805/32768)]]. Tempering it out by itself defines the [[syntonic–diatonic equivalence continuum #Superpyth (5-limit)|5-limit version of superpyth temperament]]. Notable [[edo]]s that temper it out include [[22edo|22]], [[27edo|27]], and [[49edo|49]].
 
== Comma pump example ==
[[File:Akselai superpyth comma pump (JI).wav|thumb|5-limit JI]]
[[File:Akselai superpyth comma pump (22edo).wav|thumb|22edo]]
 
The progression returns to the original chord in 22edo, but modulates downward by 20480/19683 in JI.
 
[[File:Superpyth comma pump.png|thumb|Superpyth comma pump in JI and 22edo.]]
 
[[Category:Superpyth]]
[[Category:Second]]
[[Category:Semitone]]