2187/1250: Difference between revisions

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{{Infobox Interval|2187/1250
{{Infobox Interval
| Ratio = 2187/1250
| Name = tetraptolemaic diminished seventh, ragismic 5-limit harmonic seventh
| Name = tetraptolemaic diminished seventh, ragismic 5-limit harmonic seventh
| Color name = g<sup>4</sup>7, quadgu 7th
}}
}}
'''2187/1250''', the '''tetraptolemaic diminished seventh''', is a [[5-limit]] interval very closely approximating [[7/4]], being only a [[4375/4374|ragisma]] (4375/4374) below 7/4. In the [[ragismic]] temperament, it is equated with 7/4. It is very accurately approximated by the 46th step of [[57edo]] (46\57), as 46\57 is only 0.009{{cent}} flat of this interval.
'''2187/1250''', the '''tetraptolemaic diminished seventh''', is a [[5-limit]] interval very closely approximating [[7/4]]. It is sharp of the [[32768/19683|Pythagorean diminished seventh]] by four [[81/80|syntonic commas]], hence the name. It can also be created by stacking two [[27/25]] and [[3/2]].  


[[Category:Ragismic]]
It is a [[4375/4374|ragisma]] below 7/4, a [[15625/15552|kleisma]] below the diptolemaic augmented sixth [[225/128]], and [[250/243]] below [[9/5]]. In the [[ragismic]] temperament, it is equated with 7/4. As such, it can also be called the '''ragismic 5-limit harmonic seventh'''.
 
== Approximation ==
[[57edo]] contains a very accurate approximation of 2187/1250 at its 46th step (46\57), which is only 0.009{{cent}} flat of 2187/1250.
 
== Temperaments ==
2187/1250 is the eigenmonzo of [[4/9-comma meantone]], and further equating it to [[7/4]] gives a tuning of [[flattone]].
 
== See also ==
* [[2500/2187]] – its [[octave complement]]
 
[[Category:Seventh]]
[[Category:Diminished seventh]]