15/14: Difference between revisions

- misinformation (dyads are neither otonal nor utonal). - duplicate information. Re-organize
Rewrite to better address the names (displacing "septimal major semitone", not attested anywhere)
 
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{{Infobox Interval
{{Infobox Interval
| Name = septimal diatonic semitone, septimal major semitone
| Name = septimal diatonic semitone, aberschismic chromatic semitone, major chromatic semitone
| Color name = ry1, ruyo unison
| Color name = ry1, ruyo unison
| Sound = jid_15_14_pluck_adu_dr220.mp3
| Sound = jid_15_14_pluck_adu_dr220.mp3
}}
}}
{{Wikipedia|Septimal diatonic semitone}}
{{Wikipedia|Septimal diatonic semitone}}
'''15/14''' is a [[superparticular]] ratio with a numerator which is the fifth [[triangular number]]. It is traditionally called a ''diatonic semitone'', perhaps for its proximity (and conflation in systems such as septimal [[meantone]] and [[marvel]]) with the classic diatonic semitone [[16/15]]. However, 15/14 is a ''[[chromatic semitone]]'' in both [[Helmholtz–Ellis notation]] and the [[Functional Just System]], viewed as the apotome [[2187/2048]] altered by [[5120/5103]]. [[Marc Sabat]] has taken to call it the ''major chromatic semitone'' in the same material where [[21/20]] is also named as the minor diatonic semitone<ref>Marc Sabat. [https://masa.plainsound.org/pdfs/crystal-growth.pdf ''Three Crystal Growth Algorithms in 23-limit constrained Harmonic Space'']. Plainsound Music Edition, 2008.</ref>.
'''15/14''' is an interval in [[7-limit]] [[just intonation]] measuring about 119.4 [[cent]]s, traditionally known as the '''septimal diatonic semitone''' for its proximity (and conflation in [[marvel]] tunings such as septimal [[meantone]]) with the classical diatonic semitone [[16/15]]. However, it functions as a ''[[chromatic semitone]]'', as is supported by [[Sagittal notation]], [[Helmholtz–Ellis notation]] and the [[Functional Just System]], viewed as the [[Pythagorean apotome]] altered by an [[aberschisma]]. This gives rise to the more precise name '''aberschismic chromatic semitone''', or as [[Marc Sabat]] has taken to call it, the '''major chromatic semitone'''<ref>Marc Sabat. [https://masa.plainsound.org/pdfs/crystal-growth.pdf ''Three Crystal Growth Algorithms in 23-limit constrained Harmonic Space'']. Plainsound Music Edition, 2008.</ref>.


Because it contains exactly one of each prime up to 7, it appears as the interval between many simple [[7-limit]] ratios. In particular, it is the difference between certain [[interval qualities]] of seconds, thirds, sixths, and sevenths: between classical minor and supermajor, and between subminor and classical major. These are the pairs of intervals separated by 15/14:  
Because it contains exactly one of each prime up to 7, it appears as the interval between many simple [[7-limit]] ratios. In particular, it is the difference between certain [[interval qualities]] of seconds, thirds, sixths, and sevenths: between classical minor and supermajor, and between subminor and classical major. These are the pairs of intervals separated by 15/14:  
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* [[7/5]] and [[3/2]]
* [[7/5]] and [[3/2]]


It also arises in higher limits as:  
It also arises in higher limits as the difference between:  
* [[14/13]] and [[15/13]]
* [[14/13]] and [[15/13]]
* [[14/11]] and [[15/11]]
* [[14/11]] and [[15/11]]
* [[22/15]] and [[11/7]]
* [[22/15]] and [[11/7]]
* [[26/15]] and [[13/7]]
* [[26/15]] and [[13/7]]
Finally, since it is a [[superparticular ratio]] with a numerator which is the fifth [[triangular number]], it is a [[triangle-particular]] ratio with factorization ([[25/24]])⋅([[36/35]]).


== Approximation ==
== Approximation ==