15/14: Difference between revisions

Add temperaments (generated by this interval) section, mention marvel in terminology section (not obvious to people not quite familiar with septimal meantone, so it clarifies the context)
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 may be found as the interval between many [[7-limit]] ratios, including:
'''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:
* [[28/27]] and [[10/9]]
* [[16/15]] and [[8/7]]
* [[16/15]] and [[8/7]]
* [[7/6]] and [[5/4]]
* [[7/6]] and [[5/4]]
* [[6/5]] and [[9/7]]
* [[6/5]] and [[9/7]]
* [[4/3]] and [[10/7]]
* [[7/5]] and [[3/2]]
* [[14/9]] and [[5/3]]
* [[14/9]] and [[5/3]]
* [[8/5]] and [[12/7]]
* [[8/5]] and [[12/7]]
* [[7/4]] and [[15/8]]
* [[7/4]] and [[15/8]]
* [[9/5]] and [[27/14]]
In addition, it separates the perfect fourth from the larger septimal tritone, and the perfect fifth from the smaller septimal tritone:
* [[4/3]] and [[10/7]]
* [[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]]
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* [[26/15]] and [[13/7]]
* [[26/15]] and [[13/7]]


== Terminology ==
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]]).  
15/14 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 ''[[Wikipedia:chromatic semitone|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>.


== Approximation ==
== Approximation ==
15/14 is very accurately approximated by [[10edo]] (1\10) and all [[linus]] temperaments. The [[linus comma]], 5., is the amount by which a stack of ten 15/14's falls short of the octave.
15/14 is very accurately approximated by [[10edo]] (1\10) and all [[linus]] temperaments. The [[linus comma]], 5.6{{c}}, is the amount by which a stack of ten 15/14's falls short of the octave.


In combination with [[19/17]] it forms a good approximation of [[golden meantone]]. The untempered combination of five 19/17's and two 15/14's leads to an interval that is sharp to an octave by the [[mercurial comma]]: (19/17)<sup>5</sup> × (15/14)<sup>2</sup> = 2 / (mercurial comma).  
In combination with [[19/17]] it forms a good approximation of [[golden meantone]]. The untempered combination of five 19/17's and two 15/14's leads to an interval that is sharp to an octave by the [[mercurial comma]]: (19/17)<sup>5</sup> × (15/14)<sup>2</sup> = 2 / (mercurial comma).
 
{{Interval edo approximation|max edo=131|15/14}}


== Temperaments ==
== Temperaments ==
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* [[Septidiasemi]]
* [[Septidiasemi]]
* [[Subsedia]]
* [[Subsedia]]
In addition, this [[fractional-octave temperament]] is generated by a ~15/14:
* [[Tertiosec]] (1\3)
Several [[10th-octave temperaments]] treat ~15/14 as the period, including [[decoid]] and [[linus]].
{{todo|complete list}}
{{todo|complete list}}
In addition, several [[10th-octave temperaments]] treat ~15/14 as the period, including [[decoid]] and [[linus]].


== See also ==
== See also ==
* [[28/15]] – its [[octave complement]]
* [[28/15]] – its [[octave complement]]
* [[7/5]] – its [[fifth complement]]
* [[7/5]] – its [[fifth complement]]
* [[1ed15/14]] - its [[ambitonal sequence]]
* [[List of superparticular intervals]]
* [[List of superparticular intervals]]
* [[Gallery of just intervals]]
* [[Gallery of just intervals]]