4edo: Difference between revisions

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Undo revision 230820 by MisterShafXen (talk) Only 19, 27, and perhaps 45 seem accurate enough to be usable. I don't know of anyone who uses 3edo for high-limit stuff.
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{{interwiki
{{interwiki
| de = 4edo
| de = 4-EDO
| en = 4edo
| en = 4edo
| es =  
| es =  
| ja =  
| ja = 4平均律
}}
}}
Like [[3edo]], '''4edo''' is already familiar as a chord of 12edo.  Not only that, but 4edo establishes tonality in much the same ways that 3edo does- with only two notes at a time as opposed to three aside from octave reduplications of the Tonic, though the Tonic-Antitonic contrast from 2edo also works.  Also like with 3edo, it has a theoretical interest in that it preserves a kind of outline, or skeleton, of melodic movement while erasing key distinctions concerning harmony. The 7-limit tuning map, or [[Vals_and_Tuning_Space|val]], for 4EDO goes <4 6 9 11|, all of which are distinct modulo 4. It therefore goes with tetradic harmony in much the same way that 3EDO goes with triadic harmony, mapping the [[7-limit|7-limit]] [[consistent|consistent]]ly, and sending 15/14, 21/20, 25/24, and 36/35 to the unison. Somewhat confusingly, 9/8 is mapped to the unison also.
{{Infobox ET}}
{{ED intro}}


By putting together the triples of integers which uniquely represent 7-limit tetrads in the [[The_Seven_Limit_Symmetrical_Lattices|7-limit cubic lattice of tetrads]] with the number of 4EDO steps returned by the val <4 6 9 11| we obtain a representation of the 7-limit in terms of four integers, which differs from the usual (monzo) representation in that the triple representing the chord can be swapped for another such triple, resulting in a similar note tuned to a different chord. It is even possible under some circumstances to create a sort of recombinant merging of two pieces of music by using the chords of one with the 4EDO skeletons of another.
== Theory ==
Like [[3edo]], 4edo is already familiar as a chord of [[12edo]]. Not only that, but 4edo establishes tonality in much the same ways that 3edo does—with only two notes at a time as opposed to three aside from octave reduplications of the tonic, though the Tonic-Antitonic contrast from [[2edo]] also works.  Also like with 3edo, it has a theoretical interest in that it preserves a kind of outline, or skeleton, of melodic movement while erasing key distinctions concerning harmony. The 7-limit [[mapping]], or [[val]], for 4edo goes {{val| 4 6 9 11 }}, all of which are distinct modulo 4. It therefore goes with tetradic harmony in much the same way that 3edo goes with triadic harmony, mapping the [[7-limit]] [[consistent]]ly, and sending [[15/14]], [[21/20]], [[25/24]], and [[36/35]] to the unison. Somewhat confusingly, the patent mapping of 4edo sees [[9/8]] mapped to the unison also, leading to [[Very low accuracy temperaments #Antitonic|antitonic]], though this can be traced to both [[3/2]] and [[4/3]] being mapped to 2\4.


We can also add more kinds of chords, for instance the subminor (1-7/6-3/2-5/3) and supermajor (1-9/7-3/2-9/5) to the mix, and by encoding which kind of tetrad a note reconstitute a version of 9-odd-limit tetradic harmony, again changing the harmonic content of a note without changing its 4EDO skeletal position.
By putting together the triples of integers which uniquely represent 7-limit tetrads in the [[The Seven Limit Symmetrical Lattices|7-limit cubic lattice of tetrads]] with the number of 4edo steps returned by the {{val| 4 6 9 11 }} we obtain a representation of the 7-limit in terms of four integers, which differs from the usual (monzo) representation in that the triple representing the chord can be swapped for another such triple, resulting in a similar note tuned to a different chord. It is even possible under some circumstances to create a sort of recombinant merging of two pieces of music by using the chords of one with the 4edo skeletons of another.


==Music==
We can also add more kinds of chords, for instance the subminor ([[6:7:9:10|1–7/6–3/2–5/3]]) and supermajor ([[70:90:105:126|1–9/7–3/2–9/5]]) to the mix, and by encoding which kind of tetrad a note reconstitute a version of 9-odd-limit tetradic harmony, again changing the harmonic content of a note without changing its 4edo skeletal position.


[http://clones.soonlabel.com/public/micro/gene_ward_smith/transformers/fouredo.mp3 A simple 4edo piece] by [[Gene_Ward_Smith|Gene Ward Smith]] (see [[Composing_with_tablets|Composing with tablets]] for explanation)
4edo can be viewed as a [[dual-fifth]] system (the smallest in fact, besides the trivial [[1edo]]), with the tritone and major sixth as the flat and sharp "fifths". The tritone represents 3/2 in the [[patent val]], while the major sixth represents 3/2 in the 4b val (using [[wart notation]]). The 4b val has one of the sharpest mappings of 3/2 of any [[octave]]-repeating equal temperaments, only outmatched by that of [[1edo]], and even falling outside of the 600- to 800-cent range of [[2L 1s]].
 
4edo can be seen as a trivial tuning of the [[diminished (temperament)|diminished]] temperament, since it tempers out [[648/625]] (the major diesis) by equating four minor thirds ([[6/5]]) to an octave. Alternately, it can be viewed as a critically flat [[hanson]] or [[myna]] tuning, as both 6 and 10 generators reach the best approximation to the 5th. This interpretation works best if you stretch the octaves; 4edo is the first edo that is [[The Riemann zeta function and tuning #Zeta edo lists|zeta peak but not zeta peak integer]], which means the point of maximum harmonicity is somewhat further away from pure octaves than the previous two edos. If you compress the octaves instead, it can be interpreted as a critically sharp [[subgroup temperaments #Gariberttet|gariberttet]] tuning.
 
=== Odd harmonics ===
{{Harmonics in equal|4}}
 
=== Subsets and supersets ===
4edo is the first composite edo, containing [[2edo]] as the only nontrivial subset edo.
 
== Intervals ==
{| class="wikitable center-all"
|+ style="font-size: 105%;" | Intervals of 4edo
|-
! rowspan="2" | [[Degree]]
! rowspan="2" | [[Cent]]s
! rowspan="2" | [[Interval region]]
! colspan="4" | Approximated [[JI]] intervals* ([[error]] in [[¢]])
! rowspan="2" | Audio
|-
! [[3-limit]]
! [[5-limit]]
! [[7-limit]]
! Other
|-
| 0
| 0
| Unison (prime)
| [[1/1]] (just)
|
|
|
| [[File:piano_0_1edo.mp3]]
|-
| 1
| 300
| Minor third
| [[32/27]] (+5.865)
| [[6/5]] (-15.641)
| [[7/6]] (+33.129)<br>[[25/21]] (-1.847)
| [[19/16]] (+2.487)
| [[File:piano_1_4edo.mp3]]
|-
| 2
| 600
| [[Tritone]]
|
|
| [[7/5]] (+17.488)<br>[[10/7]] (-17.488)
| [[24/17]] (+3.000)<br>[[99/70]] (-0.088)<br>[[17/12]] (-3.000)
| [[File:piano_1_2edo.mp3]]
|-
| 3
| 900
| Major sixth
| [[27/16]] (-5.865)
| [[5/3]] (+15.641)
| [[42/25]] (+1.847)<br>[[12/7]] (-33.129)
| [[32/19]] (-2.487)
| [[File:piano_3_4edo.mp3]]
|-
| 4
| 1200
| Octave
| [[2/1]] (just)
|
|
|
| [[File:piano_1_1edo.mp3]]
|}
<nowiki />* Based on treating 4edo as a subset of [[12edo]], itself treated as a 2.3.5.7.17.19 subgroup temperament; other approaches are possible.
 
== Notation ==
{| class="wikitable center-all"
|+ style="font-size: 105%;" | Notation of 4edo
|-
! rowspan="2" | [[Degree]]
! rowspan="2" | [[Cent]]s
! colspan="2" | [[12edo]] [[subset notation]]
|-
! [[5L 2s|Diatonic]] interval names
! Note names (on D)
|-
| 0
| 0
| '''Perfect unison (P1)'''
| '''D'''
|-
| 1
| 300
| Augmented second (A2)<br>'''Minor third (m3)'''
| E#<br>'''F'''
|-
| 2
| 600
| Augmented fourth (A4)<br>Diminished fifth (d5)
| G#<br>Ab
|-
| 3
| 900
| '''Major sixth (M6)'''<br>Diminished seventh (d7)
| '''B'''<br>Cb
|-
| 4
| 1200
| '''Perfect octave (P8)'''
| '''D'''
|}
 
In 4edo:
* [[ups and downs notation]] is identical to standard notation;
* Mixed [[sagittal notation]] is identical to standard notation, but pure sagittal notation exchanges sharps (#) and flats (b) for sagittal sharp ([[File:Sagittal sharp.png]]) and sagittal flat ([[File:Sagittal flat.png]]) respectively.
 
== Solfege ==
{| class="wikitable center-all"
|+ style="font-size: 105%;" | Solfege of 4edo
|-
! [[Degree]]
! [[Cents]]
! 12edo subset<br>standard [[solfege]]<br>(movable do)
! 12edo subset<br>[[Uniform solfege]]<br>(2-3 vowels)
|-
| 0
| 0
| Do (P1)
| Da (P1)
|-
| 1
| 300
| Ri (A2)<br>Me (m3)
| Ru (A2)<br>Na (m3)
|-
| 2
| 600
| Fi (A4)<br>Se (d5)
| Pa (A4)<br>Sha (d5)
|-
| 3
| 900
| La (M6)
| La (M6)<br>Tho (d7)
|-
| 4
| 1200
| Do (P8)
| Da (P8)
|}
 
== Music ==
; [[Aeterna]]
* [https://www.youtube.com/watch?v=catncLv5oSk "Mimetism"], from [https://youtube.com/playlist?list=OLAK5uy_meMItS3Zalh3jNeQ-4XVwEp0JUPO3A9rQ ''Tribute to Armodue''] (2008)
 
; [[No Clue Music]]
* [https://www.youtube.com/watch?v=JBGqDbbZ0Fw ''Dimpulse''] (2024)
 
; [[NullPointerException Music]]
* [https://www.youtube.com/watch?v=rCfWHwrEaA0 "Entering"], from [https://www.youtube.com/playlist?list=PLg1YtcJbLxnwTJkG4m0BWZWxIHj7ScdNn ''Edolian''] (2020)
 
; [[User:Phanomium|Phanomium]]
* [https://www.youtube.com/watch?v=T0J1D_E94L4 ''Diminished''] (2024)
 
; [[Rozencrantz|Rozencrantz the Sane]]
* ''Nothing of any importance'' (2006) – his contribution to the [[MMMday06|MMM day 2006]]<sup>[''where?'']</sup>
 
; [[Gene Ward Smith]]
* [https://web.archive.org/web/20201127012143/http://clones.soonlabel.com/public/micro/gene_ward_smith/transformers/fouredo.mp3 ''A simple 4EDO piece''] (2011?) – see also [[Composing with tablets]]
 
; [[STC_1003]]
* "Neainaz Antithetica, Variation II", from [https://soundcloud.com/sexytoadsandfrogsfriendcircle/sets/staffcirc-vol-7-terra-octava ''STAFFcirc vol. 7''] (2021) – [https://soundcloud.com/sexytoadsandfrogsfriendcircle/4-stc-s1003-neainaz SoundCloud] | [https://sexytoadsandfrogsfriendcircle.bandcamp.com/track/4-neainaz-antithetica-variation-ii Bandcamp]


"Nothing of any importance" by [[Rozencrantz|Rozencrantz the Sane]] (his contribution to the [[MMMday06|MMM day 2006]])
[[Category:7-limit]]
[[Category:7-limit]]
[[Category:Equal divisions of the octave]]
[[Category:Listen]]
[[Category:macrotonal]]