4edo: Difference between revisions
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'''4 equal divisions of the octave''' (or '''4edo''') is the [[tuning system]] derived by dividing the [[octave]] into 4 equal steps of 300 [[cent]]s each. | |||
== 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 tuning map, or [[Vals_and_Tuning_Space|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|7-limit]] [[consistent|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. | |||
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. | |||
[http://clones.soonlabel.com/public/micro/gene_ward_smith/transformers/fouredo.mp3 A simple 4edo piece] | 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. | ||
When viewed from a [[regular temperament]] perspective, 4edo can be seen as a tuning of the [[Dimipent_family#Dimipent|dimipent temperament]], since it tempers [[648/625]] (the major diesis) by equating four minor thirds ([[6/5]]) to an octave. | |||
== Music == | |||
{| class="wikitable sortable" | |||
!Title | |||
!Composer | |||
!Year | |||
!Genre | |||
!Additional links | |||
|- | |||
|''Nothing of any importance'' | |||
|[[Rozencrantz|Rozencrantz the Sane]] | |||
|2006 | |||
|(?) | |||
|His contribution to the [[MMMday06|MMM day 2006]] | |||
|- | |||
|[http://clones.soonlabel.com/public/micro/gene_ward_smith/transformers/fouredo.mp3 ''A simple 4edo piece''] | |||
|[[Gene Ward Smith]] | |||
|2011 (?) | |||
|Classical | |||
|Explanation: [[Composing_with_tablets|Composing with tablets]] | |||
|- | |||
|data-sort-value="Entering (from Edolian)"|[https://www.youtube.com/watch?v=rCfWHwrEaA0 "Entering"] (from [https://www.youtube.com/playlist?list=PLg1YtcJbLxnwTJkG4m0BWZWxIHj7ScdNn ''Edolian'']) | |||
|NullPointerException Music | |||
|2020 | |||
|Classical | |||
| | |||
|- | |||
|data-sort-value="Neainaz Antithetica, Variation II (from STAFFcirc vol. 7)"|"[https://soundcloud.com/sexytoadsandfrogsfriendcircle/4-stc-s1003-neainaz Neainaz Antithetica, Variation II]" (from [https://soundcloud.com/sexytoadsandfrogsfriendcircle/sets/staffcirc-vol-7-terra-octava ''STAFFcirc vol. 7'']) | |||
|STC_1003 | |||
|2021 | |||
|Electronic | |||
|[https://sexytoadsandfrogsfriendcircle.bandcamp.com/album/staffcirc-vol-7-terra-octava Album (Bandcamp)] | |||
|} | |||
[[Category:7-limit]] | [[Category:7-limit]] | ||
[[Category:Equal divisions of the octave]] | [[Category:Equal divisions of the octave]] | ||
[[Category:macrotonal]] | [[Category:macrotonal]] | ||