135/128: Difference between revisions

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it's not just close, it's a semiconvergent
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The [[5-limit]] interval '''135/128''', about 92.2 [[cent]]s in size, is called the '''ptolemaic chromatic semitone''', '''major limma''' or '''major chroma'''. It is a [[syntonic comma]] away from the Pythagorean chromatic semitone [[2187/2048]], and so is tuned justly in 1/7 comma meantone. Flattening by another syntonic comma reaches the even simpler [[25/24]].  In regular 5-limit diatonic systems, it is the chromatic semitone that compliments [[16/15]], as the two semitones add up to [[9/8]].
The [[5-limit]] interval '''135/128''', about 92.2 [[cent]]s in size, is called the '''ptolemaic chromatic semitone''', the '''major limma''' or the '''major chroma'''. It is a [[syntonic comma]] away from the Pythagorean chromatic semitone [[2187/2048]], and so is tuned justly in 1/7 comma meantone. Flattening by another syntonic comma reaches the even simpler [[25/24]].  In regular 5-limit diatonic systems, it is the chromatic semitone that compliments [[16/15]], as the two semitones add up to [[9/8]].


== Temperaments ==
== Temperaments ==

Revision as of 09:10, 16 June 2023

Interval information
Ratio 135/128
Factorization 2-7 × 33 × 5
Monzo [-7 3 1
Size in cents 92.17872¢
Names ptolemaic chromatic semitone,
major limma,
major chroma,
pelogic comma
Color name Ly1, layo unison,
Layobi comma
FJS name [math]\displaystyle{ \text{A1}^{5} }[/math]
Special properties reduced,
reduced harmonic
Tenney height (log2 nd) 14.0768
Weil height (log2 max(n, d)) 14.1536
Wilson height (sopfr(nd)) 28
Comma size medium
S-expression S3 / S4

[sound info]
Open this interval in xen-calc

The 5-limit interval 135/128, about 92.2 cents in size, is called the ptolemaic chromatic semitone, the major limma or the major chroma. It is a syntonic comma away from the Pythagorean chromatic semitone 2187/2048, and so is tuned justly in 1/7 comma meantone. Flattening by another syntonic comma reaches the even simpler 25/24. In regular 5-limit diatonic systems, it is the chromatic semitone that compliments 16/15, as the two semitones add up to 9/8.

Temperaments

If 135/128 is treated as a comma to be tempered out, it may be called the pelogic comma. It represents the difference between three perfect fourths and a just major third (plus an octave). Tempering it out results in mavila temperament.

135/128 is very close to one step of 13edo, in fact being a semiconvergent. Aluminium temperament realizes this through a regular temperament lens.

See also