15/14: Difference between revisions
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, | | 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 | '''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]] | ||
* [[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]] | |||
It also arises in higher limits as: | 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 the difference between: | |||
* [[14/13]] and [[15/13]] | * [[14/13]] and [[15/13]] | ||
* [[14/11]] and [[15/11]] | * [[14/11]] and [[15/11]] | ||
| Line 21: | Line 27: | ||
* [[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 == | ||
15/14 is very accurately approximated by [[10edo]] (1\10) and all [[linus]] temperaments. The [[linus comma]], 5. | 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 == | ||