View source for 1edo

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| de = 1-EDO
| en = 1edo
| es = 1-EDO
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| ro = 1DEO
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{{Infobox ET}}
'''1 equal divisions of the octave''' (abbreviated '''1edo'''), or '''1-tone equal temperament''' ('''1tet'''), '''1 equal temperament''' ('''1et)''' when viewed under a [[regular temperament]] perspective, is the [[tuning system]] that contains a single pitch and pitches [[octave]]s above and below that pitch. Each step of 1edo represents a frequency ratio of [[2/1]], or exactly the octave.

== Theory ==
One note repeated in octaves is an example of a [[trivial temperament]] (specifically, it is the trivial temperament of the [[2-limit]]); most existing styles of music would find little use for a single set of octaves. That said, it does retain some musical value, particularly as 1edo is contained as a subset of every [[edo]]. In terms of [[JI]] representation, all [[prime harmonic]]s but 2 are tempered to some amount of octaves.

The first piece of ''Musica ricercata'' by {{w|György Ligeti}} simulates 1edo by playing only one pitch class (A) throughout different octaves on the piano, though the piano is not itself tuned to 1edo. The last chord of the piece uses another pitch class (D), breaking the pattern.

1edo is equivalent to the [[2-limit]], [[1-odd-limit]], and 1-''p''-fdo with arbitrary value of ''p'' (including [[AFDO|1afdo]] and [[IFDO|1ifdo]]). 

=== Odd harmonics ===
{{Harmonics in equal|1|columns=15}}

== Music ==
{{Catrel|1edo tracks}}

; [[Blendy Wave]]
* [https://www.youtube.com/watch?v=zHCvfgWA2Sg ''Octaves Only''] (2023)
* [https://www.youtube.com/watch?v=Fhv78-uO5vo ''PolyTech''] (2023)

; [[Francium]]
* [https://www.youtube.com/watch?v=qCYuoq2l6Qc ''E''] (2022)

; [[Frédéric Gagné]]
* ''Play "Do"'' (2021) – [[:File:0010 - Play Do.mp3|play]] | [https://musescore.com/fredg999/play-do score]

; [[User:Wendy_gunk|Wendy Gunk]]
* [https://www.youtube.com/watch?v=YpNh8CNS4tc ''1edo howard''] (2025)

{{Wikipedia|Musica ricercata #I. Sostenuto – Misurato – Prestissimo}}

; [[Wikipedia:György Ligeti|György Ligeti]]
* [https://soundcloud.com/elizamccarthy/ligeti-musica-ricercata-i ''Musica ricercata'': I. Sostenuto – Misurato – Prestissimo] (1951–1953)

; [[Mandrake]]
* ''One Note To Tell A Story'' (2022) – [https://www.newgrounds.com/audio/listen/1114156 Newgrounds] | [https://www.youtube.com/watch?v=mDSj8SwBHRk YouTube]

; [[NullPointerException Music]]
* [https://youtu.be/kRMU-dNOs-w "Cohesion"], from [https://www.youtube.com/playlist?list=PLg1YtcJbLxnwTJkG4m0BWZWxIHj7ScdNn ''Edolian''] (2020)

; [[User:Phanomium|Phanomium]]
* [https://www.youtube.com/watch?v=A1XppPdwGJc ''Singularity''] (2024)

; [[STC_1001]]
* "Neainaz Antithetica, Theme", from [https://soundcloud.com/sexytoadsandfrogsfriendcircle/sets/staffcirc-vol-7-terra-octava ''STAFFcirc vol. 7''] (2021) – [https://soundcloud.com/sexytoadsandfrogsfriendcircle/1-stc-s1001-neainaz SoundCloud] | [https://sexytoadsandfrogsfriendcircle.bandcamp.com/track/1-neainaz-antithetica-theme Bandcamp]

== See also ==
* [[Unison]]
* [[Octave]]

[[Category:2-limit]]
[[Category:1-odd-limit]]
[[Category:Just intonation scales]]
[[Category:Listen]]