11/8: Difference between revisions

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Adjusted the Alpharabian-tuning-based terminology
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| Monzo = -3 0 0 0 1
| Monzo = -3 0 0 0 1
| Cents = 551.31794
| Cents = 551.31794
| Name = undecimal superfourth, <br>major fourth, <br>Alpharabian paramajor fourth, <br>just paramajor fourth
| Name = undecimal superfourth, <br>major fourth, <br>Axirabian paramajor fourth, <br>just paramajor fourth
| Color name = 1o4, ilo 4th
| Color name = 1o4, ilo 4th
| FJS name = P4<sup>11</sup>
| FJS name = P4<sup>11</sup>
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}}
}}


In [[11-limit]] [[just intonation]], '''11/8''' is an '''undecimal [[superfourth]]''' of about 551.3[[cent|&cent;]].  This interval has [https://en.wikipedia.org/wiki/Major_fourth_and_minor_fifth also been referred to] as the '''major fourth'''.  Furthermore, as stacks of this interval form a core axis of [[Alpharabian tuning]] (see also [[User:Aura/Aura's Ideas on Tonality #11-limit Axis Functionality]]), it can also be somewhat similarly dubbed the '''Alpharabian paramajor fourth''' or even the '''just paramajor fourth'''.
In [[11-limit]] [[just intonation]], '''11/8''' is an '''undecimal [[superfourth]]''' of about 551.3[[cent|&cent;]].  This interval has [https://en.wikipedia.org/wiki/Major_fourth_and_minor_fifth also been referred to] as the '''major fourth'''.  Furthermore, as stacks of this interval form a core axis of [[Alpharabian tuning]] (see also [[User:Aura/Aura's Ideas on Tonality #11-limit Axis Functionality]]), it can also be somewhat similarly dubbed the '''Axirabian paramajor fourth''' or even the '''just paramajor fourth'''.


This interval is the simplest superfourth in JI, and as it falls about halfway between [[12edo]]'s [[perfect fourth]] and [[tritone]], it is very xenharmonic.  As an octave-reduced overtone, it is a basis of consonance in 11-limit JI, alongside the lower odd numbers 9, 7, 5 and 3. It can be found in harmonic series chords such as 4:5:6:7:8:9:10:11:12, sitting somewhere between the much stronger and more familiar consonances of 10 (prime 5) and 12 (prime 3).
This interval is the simplest superfourth in JI, and as it falls about halfway between [[12edo]]'s [[perfect fourth]] and [[tritone]], it is very xenharmonic.  As an octave-reduced overtone, it is a basis of consonance in 11-limit JI, alongside the lower odd numbers 9, 7, 5 and 3. It can be found in harmonic series chords such as 4:5:6:7:8:9:10:11:12, sitting somewhere between the much stronger and more familiar consonances of 10 (prime 5) and 12 (prime 3).

Revision as of 01:26, 26 December 2021

Interval information
Ratio 11/8
Factorization 2-3 × 11
Monzo [-3 0 0 0 1
Size in cents 551.3179¢
Names undecimal superfourth,
major fourth,
Axirabian paramajor fourth,
just paramajor fourth
Color name 1o4, ilo 4th
FJS name [math]\displaystyle{ \text{P4}^{11} }[/math]
Special properties reduced,
reduced harmonic
Tenney norm (log2 nd) 6.45943
Weil norm (log2 max(n, d)) 6.91886
Wilson norm (sopfr(nd)) 17

[sound info]
Open this interval in xen-calc

In 11-limit just intonation, 11/8 is an undecimal superfourth of about 551.3¢. This interval has also been referred to as the major fourth. Furthermore, as stacks of this interval form a core axis of Alpharabian tuning (see also User:Aura/Aura's Ideas on Tonality #11-limit Axis Functionality), it can also be somewhat similarly dubbed the Axirabian paramajor fourth or even the just paramajor fourth.

This interval is the simplest superfourth in JI, and as it falls about halfway between 12edo's perfect fourth and tritone, it is very xenharmonic. As an octave-reduced overtone, it is a basis of consonance in 11-limit JI, alongside the lower odd numbers 9, 7, 5 and 3. It can be found in harmonic series chords such as 4:5:6:7:8:9:10:11:12, sitting somewhere between the much stronger and more familiar consonances of 10 (prime 5) and 12 (prime 3).

It is very well-represented in 24edo, making that system especially good for approximations of JI chords involving primes 3 and 11 such as 8:9:11:12. Not only that, but composers who have experience with 24edo may find it very useful not only as a fantastic addition to major chords, but also as an interesting root motion both for chord progressions within a key and for modulations to key signatures that are not in the same chain of fifths. Furthermore, these same useful functions can carry over to higher EDOs with good 11-limit representation such as 159edo.


Approximations by EDOs

Following EDOs (up to 200) contain good approximations[1] of the interval 11/8. Errors are given by magnitude, the arrows in the table show if the EDO representation is sharp (↑) or flat (↓).

EDO deg\edo Absolute
error (¢)
Relative
error ()
Equally acceptable multiples [2]
11 5\11 5.8634 5.3748
13 6\13 2.5282 2.7389 12\26
24 11\24 1.3179 2.6359 22\48
37 17\37 0.0334 0.1030 34\74, 51\111, 68\148, 85\185
50 23\50 0.6821 2.8419 46\100
61 28\61 0.4983 2.5329 56\122
63 29\63 1.0630 5.5808
85 39\85 0.7297 5.1688
87 40\87 0.4062 2.9449 80\174
98 45\98 0.2975 2.4299 90\196
124 57\124 0.2950 3.0479
135 62\135 0.2068 2.3269
137 63\137 0.5069 5.7868
159 73\159 0.3745 4.9627
161 74\161 0.2349 3.1509
172 79\172 0.1552 2.2238
198 91\198 0.1972 3.2540
  1. error magnitude below 7, both, absolute (in ¢) and relative (in r¢)
  2. Super EDOs up to 200 within the same error tolerance

See also