Petrmic chords: Difference between revisions

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The ''[[petrmic]] [[triad]]'' is a [[13-limit]], [[Dyadic_chord|essentially tempered dyadic chord]] consisting of two [[13/10]] intervals followed by a [[13/11]], in other words a 13/10-13/10-13/11 chord, tempered by the petrma, [[2200/2197]], so that it closes at the [[octave]]. Another way to say this is that it is the petrmic tempering of 1-13/10-22/13 or 1-13/11-20/13. [[EDO|Equal temperaments]] with petrmic triads include [[29edo|29]], [[37edo|37]], [[50edo|50]], [[53edo|53]], [[58edo|58]], [[84edo|84]], [[87edo|87]], [[111edo|111]], [[121edo|121]], [[140edo|140]], [[190edo|190]], [[198edo|198]], [[224edo|224]], [[311edo|311]], [[414edo|414]], [[422edo|422]], and [[612edo|612]]. 37, 50 and especially 29 have notably good petrmic triads.
'''Petrmic chords''' are [[essentially tempered dyadic chord]]s tempered by the petrma, [[2200/2197]].
[[Category:13-limit]]
 
[[Category:petrmic]]
The petrmic triad is a palindrome in the 2.5.11.13 [[subgroup]] [[13-odd-limit]], consisting of two [[13/10]] intervals followed by a [[13/11]], closing at the [[octave]]. In other words:
[[Category:triad]]
* 1-13/10-22/13 with steps 13/10-13/10-13/11.  
 
It can be extended to the following palindromic tetrad:
* 1-11/10-13/10-22/13 with steps 11/10-13/11-13/10-13/11
 
[[EDO|Equal temperaments]] with petrmic chords include {{EDOs| 29, 37, 50, 53, 58, 84, 87, 111, 121, 140, 190, 198, 224, 311, 414, 422, and 612 }}. 37, 50 and especially 29 have notably good petrmic triads.
 
[[Category:13-odd-limit]]
[[Category:Essentially tempered chords]]
[[Category:Triad]]
[[Category:Tetrad]]
[[Category:Petrmic]]