13/11: Difference between revisions

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{{Infobox Interval
{{Infobox Interval
| Name = tridecimal minor third, major minthmic minor third
| Name = tridecimal minor third, major-minthmic minor third
| Color name = 3o1u3, tholu 3rd
| Color name = 3o1u3, tholu 3rd
| Sound = jid_13_11_pluck_adu_dr220.mp3
| Sound = jid_13_11_pluck_adu_dr220.mp3
}}
}}


In [[13-limit]] [[just intonation]], '''13/11''' is a '''tridecimal minor third''', specifically the '''major minthmic minor third''', measuring about 289.2 [[cent]]s. It is the difference between the [[11/1|11th]] and [[13/1|13th]] [[harmonic]]s. The octave-reduced 11th harmonic ([[11/8]], about 551.3{{c}}) and 13th harmonic ([[13/8]], about 840.5{{c}}) are both quite xenharmonic and demand new interval categories, while 13/11 can be likened unto some kind of relatively complex minor third – it is a [[352/351|major minthma (352/351)]] narrower than the [[32/27|Pythagorean minor third (32/27)]]. It is the simplest [[neogothic major and minor|neogothic minor third]], and can function as such in a 13-limit neogothic minor triad of [[22:26:33]], with a [[3/2]] perfect fifth between 33 and 22<ref group="note">This is a [[minor minthmic chords|minor minthmic chord]] where 13/11 and [[14/11]] sum to a perfect fifth. Shown here is the simplest JI representation. </ref>. Compare this to 22:26:32 ([[11:13:16]]), which has the much more dissonant [[16/11]] as the outside interval in place of 3/2. The latter triad sounds more like a xenharmonic version of a diminished triad, and could not be confused with simpler diminished triads such as [[5:6:7]].  
In [[13-limit]] [[just intonation]], '''13/11''' is a '''tridecimal minor third''', specifically the '''major-minthmic minor third''', measuring about 289.2 [[cent]]s. It is the difference between the [[11/1|11th]] and [[13/1|13th]] [[harmonic]]s. The octave-reduced 11th harmonic ([[11/8]], about 551.3{{c}}) and 13th harmonic ([[13/8]], about 840.5{{c}}) are both quite xenharmonic and demand new interval categories, while 13/11 can be likened unto some kind of relatively complex minor third – it is a [[352/351|major minthma (352/351)]] narrower than the [[32/27|Pythagorean minor third (32/27)]]. It is the simplest [[neogothic major and minor|neogothic minor third]], and can function as such in a 13-limit neogothic minor triad of [[22:26:33]], with a [[3/2]] perfect fifth between 33 and 22<ref group="note">This is a [[minor minthmic chords|minor minthmic chord]] where 13/11 and [[14/11]] sum to a perfect fifth. Shown here is the simplest JI representation. </ref>. Compare this to 22:26:32 ([[11:13:16]]), which has the much more dissonant [[16/11]] as the outside interval in place of 3/2. The latter triad sounds more like a xenharmonic version of a diminished triad, and could not be confused with simpler diminished triads such as [[5:6:7]].  


13/11 is the classic [[mediant]] between the simpler and more familiar ratios [[6/5]] and [[7/6]], as it can be given as (6 + 7)/(5 + 6). This puts it in between the latter ratios, slightly closer to 7/6. More complex minor thirds can be generated by taking the mediant between 13/11 and 7/6 (which yields (13 + 7)/(11 + 6) = [[20/17]], the septendecimal subminor third, about 281.4{{c}}) and between 13/11 and 6/5 (which yields (13 + 6)/(11 + 5) = [[19/16]], the overtone minor third of [[19-limit]] JI, about 297.5{{c}}). See the diagram below.
13/11 is the [[mediant (operation)|classic mediant]] between the simpler and more familiar ratios [[6/5]] and [[7/6]], as it can be given as (6 + 7)/(5 + 6). This puts it in between the latter ratios, slightly closer to 7/6. More complex minor thirds can be generated by taking the mediant between 13/11 and 7/6 (which yields (13 + 7)/(11 + 6) = [[20/17]], the septendecimal subminor third, about 281.4{{c}}) and between 13/11 and 6/5 (which yields (13 + 6)/(11 + 5) = [[19/16]], the overtone minor third of [[19-limit]] JI, about 297.5{{c}}). See the diagram below.


{| class="wikitable center-all"
{| class="wikitable center-all"

Latest revision as of 14:45, 22 July 2026

Interval information
Ratio 13/11
Subgroup monzo 11.13 [-1 1
Size in cents 289.2097¢
Names tridecimal minor third,
major-minthmic minor third
Color name 3o1u3, tholu 3rd
FJS name [math]\displaystyle{ \text{m3}^{13}_{11} }[/math]
Special properties reduced
Tenney norm (log2 nd) 7.15987
Weil norm (log2 max(n, d)) 7.40088
Wilson norm (sopfr(nd)) 24

[sound info]
Open this interval in xen-calc

In 13-limit just intonation, 13/11 is a tridecimal minor third, specifically the major-minthmic minor third, measuring about 289.2 cents. It is the difference between the 11th and 13th harmonics. The octave-reduced 11th harmonic (11/8, about 551.3 ¢) and 13th harmonic (13/8, about 840.5 ¢) are both quite xenharmonic and demand new interval categories, while 13/11 can be likened unto some kind of relatively complex minor third – it is a major minthma (352/351) narrower than the Pythagorean minor third (32/27). It is the simplest neogothic minor third, and can function as such in a 13-limit neogothic minor triad of 22:26:33, with a 3/2 perfect fifth between 33 and 22[note 1]. Compare this to 22:26:32 (11:13:16), which has the much more dissonant 16/11 as the outside interval in place of 3/2. The latter triad sounds more like a xenharmonic version of a diminished triad, and could not be confused with simpler diminished triads such as 5:6:7.

13/11 is the classic mediant between the simpler and more familiar ratios 6/5 and 7/6, as it can be given as (6 + 7)/(5 + 6). This puts it in between the latter ratios, slightly closer to 7/6. More complex minor thirds can be generated by taking the mediant between 13/11 and 7/6 (which yields (13 + 7)/(11 + 6) = 20/17, the septendecimal subminor third, about 281.4 ¢) and between 13/11 and 6/5 (which yields (13 + 6)/(11 + 5) = 19/16, the overtone minor third of 19-limit JI, about 297.5 ¢). See the diagram below.

Subminor and minor third 7/6
266.9 ¢
6/5
315.6 ¢
Interval in between << 36:35
48.7 ¢
>>
Add mediant (13/11) 7/6
266.9 ¢
13/11
289.2 ¢
6/5
315.6 ¢
Intervals in between << 78:77
22.3 ¢
>> << 66:65
26.4 ¢
>>
Add mediants (20/17 and 19/16) 7/6
266.9 ¢
20/17
281.4 ¢
13/11
289.2 ¢
19/16
297.5 ¢
6/5
315.6 ¢
Intervals in between << 120:119 >>
14.5 ¢
<< 221:220 >>
7.9 ¢
<< 209:208 >>
8.3 ¢
<< 96:95 >>
18.1 ¢

Approximation

This interval is well approximated by 4\17 (282.353 cents), and even better, by 7\29 (289.655 cents).


Edo approximations for 13/11 (289.21 ¢)
≤ 80edo, relative error ≤ 10%
Edo Step size Cents (¢) Absolute error (¢) Relative error (%)
4 1\4 300.00 +10.79 +3.60
8 2\8 300.00 +10.79 +7.19
17 4\17 282.35 -6.86 -9.71
21 5\21 285.71 -3.50 -6.12
25 6\25 288.00 -1.21 -2.52
29 7\29 289.66 +0.45 +1.08
33 8\33 290.91 +1.70 +4.67
37 9\37 291.89 +2.68 +8.27
46 11\46 286.96 -2.25 -8.64
50 12\50 288.00 -1.21 -5.04
54 13\54 288.89 -0.32 -1.44
58 14\58 289.66 +0.45 +2.15
62 15\62 290.32 +1.11 +5.75
66 16\66 290.91 +1.70 +9.35
75 18\75 288.00 -1.21 -7.56
79 19\79 288.61 -0.60 -3.96

See also

External links

  • The Noble Mediant by Margo Schulter and David Keenan, the earliest description of 13/11 as the "neo-Gothic" minor third

Notes

  1. This is a minor minthmic chord where 13/11 and 14/11 sum to a perfect fifth. Shown here is the simplest JI representation.