Keemic chords: Difference between revisions

m Recategorize
m Recategorize
 
(6 intermediate revisions by the same user not shown)
Line 1: Line 1:
A '''magical seventh''' is an [[11-limit]] [[essentially tempered dyadic chord]] consisting of three sharp [[6/5|minor thirds]] and an [[8/7]], in other words a 6/5-6/5-6/5-8/7 chord, which closes at the [[octave]] since both [[100/99]] and [[385/384]] (and therefore [[875/864]]) are [[Tempering out|tempered out]]. This means that in the 11-limit 4&7&15 [[Planar temperaments|planar temperament]] tempering these out, the chord is the tempering of 1-6/5-16/11-7/4.
A '''keemic chord''' is an [[11-odd-limit]] [[essentially tempered chord]] in the [[keemic]] temperament. Since [[100/99]] is [[tempering out|tempered out]], [[ptolemismic chords]] are also keemic chords; since [[385/384]] is tempered out, [[keenanismic chords]] are also keemic chords. Aside from these, there are also essentially keemic tempered chords.  


In an optimized tuning for the 4&7&15 temperament, the [[marvel]] comma [[225/224]] shrinks in size and may reverse direction, and adding it to the list of commas does little tuning [[damage]]; this results in 11-limit [[magic]] temperament, which has the same [[optimal patent val]] ([[104edo]]). Hence [[magic]] (19&22) temperament is practically the most accurate temperament that include this chord. Magic, however, does give it a [[Graham complexity]] of 12, so it doesn't appear that often.
The most basic of these is the '''magical seventh chord''', consisting of three sharp [[6/5|classical minor thirds]] and a [[8/7|septimal whole tone]], which closes at the [[octave]] since both [[100/99]] and [[385/384]] (and therefore [[875/864]]) are [[tempering out|tempered out]]. This means the chord is the tempering of
* 1–6/5–16/11–7/4 with steps 6/5, 6/5, 6/5, 8/7.
 
In an optimized tuning for the keemic temperament, the [[marvel]] comma [[225/224]] shrinks in size and may reverse direction, and adding it to the list of commas does little tuning [[damage]]; this results in 11-limit [[magic]] temperament, which has the same [[optimal patent val]] ([[104edo]]). Hence [[magic]] (19&22) temperament is practically the most accurate temperament that include this chord. Magic, however, does give it a [[Graham complexity]] of 12, so it does not appear that often.


Other temperaments that feature this chord prominently include 11-limit [[keemun]], [[superkleismic]], [[porcupine]] and [[doublewide]].
Other temperaments that feature this chord prominently include 11-limit [[keemun]], [[superkleismic]], [[porcupine]] and [[doublewide]].


[[Category:11-odd-limit]]
For other tetrads, there are
* 1–5/4–16/11–9/5 with steps 5/4, 7/6, 5/4, 10/9;
* 1–12/11–5/4–9/5 with steps 12/11, 8/7, 16/11, 10/9, and its inverse
* 1–12/11–6/5–7/4 with steps 12/11, 10/9, 16/11, 8/7.
 
For pentads, there are
* 1–12/11–5/4–3/2–9/5 with steps 12/11, 8/7, 6/5, 6/5, 10/9, and its inverse
* 1–6/5–11/8–3/2–5/3 with steps 6/5, 8/7, 12/11, 10/9, 6/5;
* 1–5/4–11/8–3/2–12/7 with steps 5/4, 11/10, 12/11, 8/7, 7/6, and its inverse
* 1–12/11–6/5–3/2–7/4 with steps 12/11, 11/10, 5/4, 7/6, 8/7.
 
The count of keemic chords is therefore tetrads: 4, and pentads: 4, for a total of 8.
 
[[Category:11-odd-limit chords]]
[[Category:Essentially tempered chords]]
[[Category:Essentially tempered chords]]
[[Category:Tetrads]]
[[Category:Pentads]]
[[Category:Pentads]]
[[Category:Supermagic]]
[[Category:Keemic]]