31edo: Difference between revisions

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Theory: I don't think that part's needed, actually
 
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One step of 31edo, measuring about 38.7{{c}}, is called a [[diesis]] because it stands in for several intervals called ''dieses'' (most notably, [[128/125]] and [[648/625]]) which are tempered out in [[12edo]]. The diesis is a defining sound of 31edo; when it does not appear directly in a scale, it often shows up as the difference between two or more intervals of a similar size. The diesis is demonstrated in [[SpiralProgressions]]. [[Zhea Erose]]'s 31edo music uses the interval frequently.
One step of 31edo, measuring about 38.7{{c}}, is called a [[diesis]] because it stands in for several intervals called ''dieses'' (most notably, [[128/125]] and [[648/625]]) which are tempered out in [[12edo]]. The diesis is a defining sound of 31edo; when it does not appear directly in a scale, it often shows up as the difference between two or more intervals of a similar size. The diesis is demonstrated in [[SpiralProgressions]]. [[Zhea Erose]]'s 31edo music uses the interval frequently.


In terms of interval categories, because 31edo is a meantone system, the major and minor seconds, thirds, sixth, and sevenths on the chain of fifths are equated to [[5-limit]] intervals, those being [[16/15]], [[10/9]], [[6/5]], [[5/4]], and their [[octave complement]]s. 31edo maps the chromatic semitone to two steps, meaning there are "[[neutral (interval quality)|neutral]]" intervals between minor and major ones, which are not found in [[12edo]]. They can be represented by [[11-limit]] intervals, with [[11/10]]~[[12/11]] being a neutral second, and [[11/9]]~[[27/22]] a neutral third. One step in the other direction from the classical intervals are the subminor and supermajor intervals, which can be seen as intervals of prime [[7/1|7]]. The subminor second is [[21/20]]~[[28/27]], the supermajor second [[8/7]], the subminor third [[7/6]], and the supermajor third [[9/7]]~[[14/11]]. 31edo thus has five varieties of seconds and thirds, which is much more than the two varieties in 12edo.
In terms of interval categories, because 31edo is a meantone system, the major and minor seconds, thirds, sixth, and sevenths on the chain of fifths are equated to [[5-limit]] intervals, those being [[16/15]], [[10/9]], [[6/5]], [[5/4]], and their [[octave complement]]s. 31edo maps the chromatic semitone to two steps, meaning there are "[[neutral (interval quality)|neutral]]" intervals between minor and major ones, which are not found in [[12edo]]. They can be represented by [[11-limit]] intervals, with [[11/10]]~[[12/11]] being a neutral second, and [[11/9]]~[[27/22]] a neutral third. One step in the other direction from the classical intervals are the subminor and supermajor intervals, which can be seen as intervals of prime [[7/1|7]]. The subminor second is [[21/20]]~[[28/27]], the supermajor second [[8/7]], the subminor third [[7/6]], and the supermajor third [[9/7]]~[[14/11]]. 31edo thus has five varieties of seconds and thirds each, which is much more than the two varieties available in 12edo.


=== Prime harmonics ===
=== Prime harmonics ===
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| 38.7
| 38.7
| Super-unison
| Super-unison
| [[36/35]], [[45/44]], [[49/48]], [[50/49]], [[64/63]]
| [[36/35]], [[45/44]], [[49/48]], [[50/49]], [[64/63]], [[128/125]]
| {{UDnote|step=1}}
| {{UDnote|step=1}}
|-
|-
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| 154.8
| 154.8
| Neutral second
| Neutral second
| [[11/10]], [[12/11]], [[13/12]]
| [[11/10]], [[12/11]], [[13/12]], [[35/32]]
| {{UDnote|step=4}}
| {{UDnote|step=4}}
|-
|-
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| 541.9
| 541.9
| Superfourth
| Superfourth
| [[11/8]], [[15/11]], [[26/19]], ''[[18/13]]''
| [[11/8]], [[15/11]], [[26/19]], ''[[18/13]]'', [[48/35]]
| {{UDnote|step=14}}
| {{UDnote|step=14}}
|-
|-
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| 658.1
| 658.1
| Subfifth
| Subfifth
| [[16/11]], [[19/13]], [[22/15]], ''[[13/9]]''
| [[16/11]], [[19/13]], [[22/15]], ''[[13/9]]'', [[35/24]]
| {{UDnote|step=17}}
| {{UDnote|step=17}}
|-
|-
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| 1045.2
| 1045.2
| Neutral seventh
| Neutral seventh
| [[11/6]], [[20/11]], [[24/13]]
| [[11/6]], [[20/11]], [[24/13]], [[64/35]]
| {{UDnote|step=27}}
| {{UDnote|step=27}}
|-
|-
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| 1161.3
| 1161.3
| Sub-octave
| Sub-octave
| [[35/18]], [[49/25]], [[63/32]], [[88/45]], [[96/49]]
| [[35/18]], [[49/25]], [[63/32]], [[88/45]], [[96/49]], [[125/64]]
| {{UDnote|step=30}}
| {{UDnote|step=30}}
|-
|-
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=== Other Instruments ===
=== Other Instruments ===
[[File:31edo array kalimba.jpg|none|thumb|640x640px|31edo array kalimba built by Tristan Bay; 3 octaves, 94 keys, and laid out in circle-of-fourths meantone tuning]]
[[File:31edo array kalimba.jpg|none|thumb|640x640px|31edo array kalimba built by [[Tristan Bay]]; 3 octaves, 94 keys, and laid out in circle-of-fourths meantone tuning]]


=== Lumatone ===
=== Lumatone ===
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=== Skip fretting ===
=== Skip fretting ===
'''[[Skip fretting system 31 2 9]]''' is a [[skip fretting]] system for 31edo.
'''[[Skip fretting system 31 2 9]]''' is a [[skip fretting]] system for 31edo.


'''[[Skip fretting system 31 3 7]]''' is another skip fretting system for 31edo.
'''[[Skip fretting system 31 3 7]]''' is another skip fretting system for 31edo.


'''Skip fretting system 31 2 5''' is another skip fretting system for 31edo. All examples on this page are for 7-string [[guitar]].
'''Skip fretting system 31 2 5''' is another skip fretting system for 31edo. All examples on this page are for 7-string [[guitar]].