13/12: Difference between revisions

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'''13/12'''
{{Infobox Interval
|-2 -1 0 0 0 1>
| Name = (lesser) tridecimal neutral second
| Color name = 3o2, tho 2nd
| Sound = jid_13_12_pluck_adu_dr220.mp3
}}


138.57266 cents
In [[13-limit]] [[just intonation]], '''13/12''' is the '''(lesser) tridecimal neutral second''' of about 138.6¢. It is a [[superparticular]] interval, as it is found in the harmonic series between the 13th and the 12th harmonics (between [[13/8]] and [[3/2]] in the octave). It is flat of the [[11-limit]] lesser neutral second of [[12/11]] by [[144/143]] (about 12.1¢), and sharp of the 13-limit large semitone of [[14/13]] by [[169/168]] (about 10.3¢).


[[File:jid_13_12_pluck_adu_dr220.mp3]] [[:File:jid_13_12_pluck_adu_dr220.mp3|sound sample]]
== Approximation ==
It is approximated to within about 0.11 [[cents]] by the 3-step interval of [[26edo]].
{{Interval edo approximation|{{PAGENAME}}}}


In [[13-limit|13-limit]] [[Just_intonation|Just Intonation]], 13/12 is a neutral second of about 138.6¢. It is a [[superparticular|superparticular]] interval, as it is found in the harmonic series between the 13th and the 12th overtone (between [[13/8|13/8]] and [[3/2|3/2]] in the octave). It is flat of the [[11-limit|11-limit]] lesser neutral second of [[12/11|12/11]] by [[144/143|144/143]] (about 12.1¢), and sharp of the 13-limit large semitone of [[14/13|14/13]] by [[169/168|169/168]] (about 10.3¢).
== Temperaments ==
13/12 can be used to generate [[bleu]] temperament in the 2.3.7.11.13 subgroup, mapping [[3/2]] to +5 generators, [[7/4]] to +7 generators, [[11/8]] to +4 generators, and [[13/8]] to +6 generators.


The neutral second in [[17edo|17edo]] is about 141.2¢, about 2.6¢ sharp of 13/12. Thus, if 10\17 (ten degrees of 17edo) is taken to approximate 3/2 and 12\17 taken to approximate 13/8, you can generate a 13-limit harmonic triad that approximates an 8:12:13 chord with a good 13/12.
A slightly sharp 13/12 generates [[glacier]] temperament, which equates 5 13/12's to 3/2 like bleu. This temperament has an extension to the 2.3.7.11.13.23.29 subgroup which is more complex but much more accurate than bleu.


See: [[Gallery_of_Just_Intervals|Gallery of Just Intervals]]     [[Category:13-limit]]
== See also ==
[[Category:interval]]
* [[24/13]] – its [[octave complement]]
[[Category:just_interval]]
* [[18/13]] – its [[fifth complement]]
[[Category:neutral_2nd]]
* [[Gallery of just intervals]]
[[Category:ratio]]
* [[List of superparticular intervals]]
[[Category:second]]
 
[[Category:Second]]
[[Category:Neutral second]]

Latest revision as of 05:30, 27 January 2026

Interval information
Ratio 13/12
Factorization 2-2 × 3-1 × 13
Monzo [-2 -1 0 0 0 1
Size in cents 138.5727¢
Name (lesser) tridecimal neutral second
Color name 3o2, tho 2nd
FJS name [math]\displaystyle{ \text{m2}^{13} }[/math]
Special properties superparticular,
reduced
Tenney norm (log2 nd) 7.2854
Weil norm (log2 max(n, d)) 7.40088
Wilson norm (sopfr(nd)) 20

[sound info]
Open this interval in xen-calc

In 13-limit just intonation, 13/12 is the (lesser) tridecimal neutral second of about 138.6¢. It is a superparticular interval, as it is found in the harmonic series between the 13th and the 12th harmonics (between 13/8 and 3/2 in the octave). It is flat of the 11-limit lesser neutral second of 12/11 by 144/143 (about 12.1¢), and sharp of the 13-limit large semitone of 14/13 by 169/168 (about 10.3¢).

Approximation

It is approximated to within about 0.11 cents by the 3-step interval of 26edo.

Edo approximations for 13/12 (138.57 ¢)
≤ 80edo, relative error ≤ 10%
Edo Step size Cents (¢) Absolute error (¢) Relative error (%)
8 1\8 150.00 +11.43 +7.62
9 1\9 133.33 -5.24 -3.93
17 2\17 141.18 +2.60 +3.69
18 2\18 133.33 -5.24 -7.86
26 3\26 138.46 -0.11 -0.24
34 4\34 141.18 +2.60 +7.38
35 4\35 137.14 -1.43 -4.17
43 5\43 139.53 +0.96 +3.45
44 5\44 136.36 -2.21 -8.10
52 6\52 138.46 -0.11 -0.48
60 7\60 140.00 +1.43 +7.14
61 7\61 137.70 -0.87 -4.41
69 8\69 139.13 +0.56 +3.21
70 8\70 137.14 -1.43 -8.34
78 9\78 138.46 -0.11 -0.72

Temperaments

13/12 can be used to generate bleu temperament in the 2.3.7.11.13 subgroup, mapping 3/2 to +5 generators, 7/4 to +7 generators, 11/8 to +4 generators, and 13/8 to +6 generators.

A slightly sharp 13/12 generates glacier temperament, which equates 5 13/12's to 3/2 like bleu. This temperament has an extension to the 2.3.7.11.13.23.29 subgroup which is more complex but much more accurate than bleu.

See also