20480/19683: Difference between revisions

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Sectioning. Linking. - 17edo in favor of 49edo. + category
 
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| Color name = sayo 2nd, sy2, Sayo comma
| Color name = sayo 2nd, sy2, Sayo comma
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'''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. When treated as a [[comma]] to be 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 [[Archytas_clan#Superpyth|the 5-limit version of superpyth temperament]]. Notable [[edo]]s that temper it out include [[17edo|17]], [[22edo|22]], and [[27edo|27]].
'''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.  
 
== 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 ==
== Comma pump example ==
[[File:Akselai superpyth comma pump (JI).wav|thumb|5-limit JI]]
[[File:Akselai superpyth comma pump (JI).wav|thumb|5-limit JI]]
[[File:Akselai superpyth comma pump (22edo).wav|thumb|22edo]]
[[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.
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.]]
[[File:Superpyth comma pump.png|thumb|Superpyth comma pump in JI and 22edo.]]


[[Category:Superpyth]]
[[Category:Second]]
[[Category:Second]]
[[Category:Semitone]]
[[Category:Semitone]]

Latest revision as of 06:21, 1 May 2026

Interval information
Ratio 20480/19683
Factorization 212 × 3-9 × 5
Monzo [12 -9 1
Size in cents 68.71871¢
Names retroptolemaic minor second,
superpyth comma
Color name sayo 2nd, sy2, Sayo comma
FJS name [math]\displaystyle{ \text{m2}^{5} }[/math]
Special properties reduced
Tenney norm (log2 nd) 28.5866
Weil norm (log2 max(n, d)) 28.6439
Wilson norm (sopfr(nd)) 56
Open this interval in xen-calc

20480/19683, the retroptolemaic minor second, is a 5-limit interval measuring about 68.7 ¢. It gets its name from being equal to being one syntonic comma (81/80) flatter than the Pythagorean limma (256/243), in contrast to 16/15 which is a syntonic comma sharper than a Pythagorean limma.

Temperaments

When treated as a comma to be tempered out, it is the superpyth comma, and is the difference between 5/4 and an octave-reduced stack of nine 3/2's, as well as 25/24 minus a schisma (32805/32768). Tempering it out by itself defines the 5-limit version of superpyth temperament. Notable edos that temper it out include 22, 27, and 49.

Comma pump example

5-limit JI
22edo

The progression returns to the original chord in 22edo, but modulates downward by 20480/19683 in JI.

Superpyth comma pump in JI and 22edo.