28/27: Difference between revisions

Expansion
Rewrite; simplify essentially duplicate names; - "small septimal chroma", not attested anywhere
 
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{{Infobox Interval
{{Infobox Interval
| Icon =
| Name = septimal third-tone, septimal minor second, subminor second, trienstonic comma
| Ratio = 28/27
| Monzo = 2 -3 0 1
| Cents = 62.9609
| Name = septimal chroma, septimal third-tone
| Color name = z2, zo 2nd
| Color name = z2, zo 2nd
| Sound = jid_28_27_pluck_adu_dr220.mp3
| Sound = jid_28_27_pluck_adu_dr220.mp3
| Comma = yes
}}
}}
{{Wikipedia| Septimal third tone }}


The [[superparticular]] interval '''28/27''' (also '''septimal chroma''' or '''septimal third-tone''') has the seventh triangular number as a numerator and is the difference between [[15/14]] and [[10/9]], [[9/8]] and [[7/6]], [[9/7]] and [[4/3]], [[3/2]] and [[14/9]], [[12/7]] and [[16/9]], and [[9/5]] and [[28/15]].
In [[7-limit]] [[just intonation]], '''28/27''', measuring about 63.0 [[cent]]s, is conventionally known as the '''septimal third-tone'''. It arises as the difference between [[15/14]] and [[10/9]], between [[9/8]] and [[7/6]], between [[9/7]] and [[4/3]], between [[3/2]] and [[14/9]], between [[12/7]] and [[16/9]], and between [[9/5]] and [[28/15]]. Since it is flat of the [[Pythagorean limma]] by a [[64/63|septimal comma (64/63)]], it may be called the '''septimal (sub)minor second''' if treated as an interval in its own right, analogous to the septimal major second [[8/7]], which has the same relationship with [[9/8]], and such classification suggests the function of a strong leading tone added to the traditional harmony.  


If treated as an interval in its own right, it may be described as the septimal minor second, since it differs from the Pythagorean minor second [[256/243]] by [[64/63]], and from [[16/15]] by [[36/35]]. This is analogous to the septimal major second [[8/7]], which has the same relationship with [[9/8]] and [[10/9]], respectively. Such classification suggests the function of a strong leading tone added to the traditional harmony.  
Finally, since it is a [[superparticular ratio]] which has the seventh [[triangular number]] as a numerator, it a [[triangle-particular]] ratio with factorization ([[49/48]])⋅(64/63).
 
== Approximation ==
This interval is very accurately approximated by [[19edo]] (1\19), and hence the [[enneadecal]] temperament. 
 
{{Interval edo approximation|28/27}}
 
== Temperaments ==
If treated as a [[comma]] to be tempered out, 28/27 may be called the '''trienstonic comma''', which leads to the '''trienstonic''' temperament.
 
See [[Trienstonic clan]] for the rank-2 [[clan]] of temperaments where it is tempered out.
 
== Notation ==
=== Sagittal notation ===
In the [[Sagittal]] system, this comma (possibly tempered) is represented (in a secondary role) by the sagittal {{sagittal| (|\ }} and is called the '''7 large diesis''', or '''7L''' for short, because the simplest interval it notates is 7/1 (equivalently, 7/4), as for example in C–A{{nbhsp}}{{sagittal | (|\ }}. The primary role of {{sagittal| (|\ }} is [[8505/8192 #Sagittal notation|8505/8192]] (35L). The downward version is called '''1/7L''' or '''7L down''' and is represented (in a secondary role) by {{sagittal| (!/ }}.


== See also ==
== See also ==
* [[Gallery of Just Intervals]]
* [[27/14]] – its [[octave complement]]
* [[27/14]] - its [[inverse interval]]
* [[81/56]] its [[fifth complement]]
* [https://en.wikipedia.org/wiki/Septimal_third_tone Septimal third tone - Wikipedia]
* [[9/7]] – its [[fourth complement]]
* [[List of superparticular intervals]]
* [[Gallery of just intervals]]
* [[Trienstonoschisma]], the difference by which a stack of five 28/27's falls short of [[6/5]]


[[Category:7-limit]]
[[Category:Second]]
[[Category:Interval]]
[[Category:Superparticular]]
[[Category:Semitone]]
[[Category:Semitone]]
[[Category:Third tone]]
[[Category:Third tone]]
[[Category:Chroma]]
[[Category:Chroma]]
[[Category:Trienstonic]]
[[Category:Commas named for the intervals they stack]]