40/21: Difference between revisions

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Rewrite. De-highlight "septimal diminished octave" as major sources agree this is a major seventh
 
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{{Infobox Interval
{{Infobox Interval
| JI glyph =
| Name = septimal acute major seventh, aberschismic major seventh
| Ratio = 40/21
| Color name = ry7, ruyo 7th
| Monzo = 3 -1 1 -1
| Cents = 1115.53281
| Name = small septimal suboctave
| Color name =  
| FJS name =
| Sound = jid_40_21_pluck_adu_dr220.mp3
| Sound = jid_40_21_pluck_adu_dr220.mp3
}}
}}
'''40/21''', conventionally known as the '''septimal acute major seventh''', is an interval in [[7-limit]] [[just intonation]] measuring about 1115.5 [[cent]]s. Despite being approximated by the diminished octave in systems like septimal [[meantone]], and even being called the ''septimal diminished octave'' by some musicians due to analogy with [[21/20]] being called the "septimal chromatic semitone", 40/21 functions as a major seventh, as is supported by [[Sagittal notation]], [[Helmholtz–Ellis notation]] and [[Functional Just System]], viewed as the [[243/128|Pythagorean major seventh (243/128)]] altered by an [[aberschisma]]. This gives rise to the more precise name '''aberschismic major seventh'''.


'''40/21''' is a [[7-limit]] interval.
== Approximation ==
{{Interval edo approximation|40/21}}


[[category:interval]]
== See also ==
[[category:7-limit]]
* [[21/20]] – its [[octave complement]]
[[Category:todo:expand]]
* [[Gallery of just intervals]]
 
[[Category:Seventh]]
[[Category:Major seventh]]