Augmented triad: Difference between revisions

The definition of P1-M3-A5 is a meantone-centrist definition. This is a chord of the augmented temp. Quick rework to reveal the implications of this chord.
Rework to further explain what's going on in contemporary 12edo music
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{{Wikipedia|Augmented triad}}
{{Wikipedia|Augmented triad}}


The '''augmented triad''' comprises three identical major thirds closing at the [[octave]]. It is a [[5-odd-limit]] [[essentially tempered chord]] of the [[augmented (temperament)|augmented]] temperament, the temperament named after this chord.  
The '''augmented triad''' is a [[triad]] traditionally described as comprising a root, [[major]] third, and [[interval quality|augmented]] fifth. In contemporary [[12edo]] music, the augmented fifth is [[enharmonic equivalence|enharmonically equivalent]] to a minor sixth, approximating [[8/5]], with the major third approximating [[5/4]], so it is a stack of two [[~]]5/4's making up ~8/5, [[tempering out]] [[128/125]]. In other words, three identical ~5/4's close at the [[octave]], which implies it is a [[5-odd-limit]] [[essentially tempered chord]] of the [[augmented (temperament)|augmented]] temperament, the temperament named after this chord.  
* (Augmented) 1 – 5/4 – 8/5, with steps 5/4, 5/4, 5/4.  
* (Augmented) 1 – 5/4 – 8/5, with steps 5/4, 5/4, 5/4.  


== In meantone ==
== In meantone ==
Before the ubiquity of [[12edo]], an augmented triad was simply treated as a [[triad]] comprising a root, [[major]] third, and [[interval quality|augmented]] fifth, and did not imply an equal tuning of all three intervals. It can be viewed as a [[9-odd-limit]] essentially tempered chord of [[marvel]]. See [[marvel chords]]. This is still compatible with 12edo and is perhaps as authentic as the 5-odd-limit interpretation above.  
Before the ubiquity of [[12edo]], an augmented triad did not imply an equal tuning of all three thirds (technically, two major thirds and a diminished fourth). It can be viewed as a [[9-odd-limit]] essentially tempered chord of [[marvel]]. See [[marvel chords]]. This is still compatible with 12edo and is perhaps as authentic as the 5-odd-limit interpretation above.  


== In just intonation ==
== In just intonation ==