13/8: Difference between revisions

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{{Infobox Interval
{{Infobox Interval
| JI glyph =
| Name = (lesser) tridecimal neutral sixth
| Ratio = 13/8
| Color name = 3o6, tho 6th
| Monzo = -3 0 0 0 0 1
| Cents = 840.52766
| Name = tridecimal neutral sixth
| Sound = jid_13_8_pluck_adu_dr220.mp3
| Sound = jid_13_8_pluck_adu_dr220.mp3
| Color name = 3o6, tho 6th
}}
}}


13/8 is a neutral sixth measuring about 840.5¢, falling between the categories of minor sixth and major sixth. In [[13-limit|13-limit]] [[Just_intonation|Just Intonation]], 13/8, as an octave-reduced 13th harmonic, is treated as a basic component of harmony. In the harmonic series and in chords based on it, 13/8 sits between the more familiar consonances of [[3/2|3/2]] and [[7/4|7/4]], separated from each by the [[superparticular|superparticular]] ratios [[13/12|13/12]] and [[14/13|14/13]], respectively. It differs from the [[11-limit|11-limit]] neutral sixth [[18/11|18/11]] by [[144/143|144/143]], about 12..
'''13/8''' is the '''(lesser) tridecimal neutral sixth''', which measures about 840.5¢, falling between the categories of minor sixth and major sixth. In [[13-limit]] [[just intonation]], 13/8, as an octave-reduced 13th harmonic, is treated as a basic component of harmony. In the harmonic series and in chords based on it, 13/8 sits between the more familiar consonances of [[3/2]] and [[7/4]], separated from each by the [[superparticular]] ratios [[13/12]] and [[14/13]], respectively. The word "lesser" is added when necessary to differentiate it from [[64/39]], another tridecimal neutral sixth. It may also be treated as a type of augmented fifth, as the sum of [[5/4]] and [[13/10]].
 
13/8 differs from the Pythagorean minor sixth [[128/81]] by [[1053/1024]], about 48¢, from the classic minor sixth [[8/5]] by [[65/64]], about 27¢, from the undecimal neutral sixth [[18/11]] by [[144/143]], about 12¢, and from the rastmic neutral sixth [[44/27]] by [[352/351]], about 4.9¢.
 
== Approximation ==
13/8 is a fraction of a cent away from the neutral sixth found in the [[10edo|10''n''-edo]] family (7\10).
 
This interval is a ratio of two consecutive Fibonacci numbers, therefore it approximates the [[golden ratio]]. In this case, 13/8 is ~7.4 [[cent|¢]] sharp of the golden ratio.
 
== See also ==
* [[16/13]] – its [[octave complement]]
* [[64/39]] – the greater tridecimal neutral sixth
* [[Gallery of just intervals]]


See: [[Gallery_of_Just_Intervals|Gallery of Just Intervals]]      [[Category:13-limit]]
[[Category:Sixth]]
[[Category:interval]]
[[Category:Neutral sixth]]
[[Category:just_interval]]
[[Category:Golden ratio approximations]]
[[Category:listen]]
[[Category:neutral_sixth]]
[[Category:ratio]]
[[Category:sixth]]
[[Category:tridecimal]]
[[Category:untwelve]]