31edo: Difference between revisions

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Octave stretch
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Moved scales section to be consistent with other edo pages
 
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[[File:31-edo spiral.png|582x582px]]
[[File:31-edo spiral.png|582x582px]]
== Scales ==
* [[Meantone5]]
* [[Meantone7]]
* [[Meantone12]]
=== MOS scales ===
{{main| List of MOS scales in 31edo }}
The fact that 31edo has meantone diatonic and chromatic scales is well-known, but some other [[MOS]]es and MOS chains{{clarify}} are also useful:
* 9\31, the neutral third, generates [[ultrasoft]] [[mosh]] and [[superhard]] [[dicotonic]] MOSes.
* 11\31, the supermajor third or diminished fourth, generates a [[TAMNAMS|parahard]] [[sensoid]] scale with resolution from neutral thirds, sixths, and sevenths to perfect fourths, fifths, and octaves, and a [[semihard]] [[3L 8s]] scale with a jagged-but-chromatic feel.
* 12\31 generator generates a [[semihard]] oneirotonic ([[5L 3s]]) scale, similar to the 5L 3s scale in [[13edo]] but with the 9/8, 5/4, and 7/6 better in tune and with the flat fifth close to [[19/13]].
* A chain of 5\31 whole tones is exceptionally rich in 4:5:7 chords, which are approximated very well in 31edo.
* If you're fond of orwell tetrads (which are also found in 31edo's oneirotonic), you will like the 7\31 (271.0{{c}}) subminor third generator. The [[ultrasoft]] 9-tone orwelloid [[4L 5s]] MOS could be treated as a 9-tone well temperament.
* It has close approximations to [[6edf]] (→ [[miracle]]) and [[9edf]] (→ [[Carlos Alpha]]), fifth-equivalent equal divisions that hit many good JI approximations.
See [[#Rank-2 temperaments]] for a table of MOSes and their temperament interpretations.
=== Harmonic scales ===
31edo approximates Mode 8 of the [[harmonic series]] okay, but many intervals between the harmonics aren't distinguished, most importantly 9/8 (major tone) and 10/9 (minor tone), as 31EDO is a meantone temperament. The interval between the 8th and 11th harmonics is approximated okay, but the intervals between the 11th harmonic and closer harmonics such as the 12th and 9th harmonics are approximated much better. 31edo's closest approximation of 13/8, the neutral sixth, is significantly sharper than just and only vaguely suggests the [[13-limit]].
The steps are: 5 5 4 4 4 3 3 3.
{| class="wikitable"
|-
! Overtones in "Mode 8":
| 8
| 9
| 10
| 11
| 12
| 13
| 14
| 15
| 16
|-
! …as JI Ratio from 1/1:
| 1/1
| 9/8
| 5/4
| 11/8
| 3/2
| 13/8
| 7/4
| 15/8
| 2/1
|-
! …in cents:
| 0
| 203.9
| 386.3
| 551.3
| 702.0
| 840.5
| 968.8
| 1088.3
| 1200.0
|-
! Nearest degree of 31edo:
| 0
| 5
| 10
| 14
| 18
| 22
| 25
| 28
| 31
|-
! …in cents:
| 0
| 193.5
| 387.1
| 541.9
| 696.8
| 851.6
| 967.7
| 1083.9
| 1200.0
|}
In mode 16, the most closely-matched harmonics are the composite ones, 21 and 25. Of the other harmonics:
* 17 is sharp, like 13. In fact, the 17:13 ratio is matched within a tenth of a cent.
* 19 is also sharp, like 13 and 17. The 19:17 ratio is about one cent sharp. 31edo could be considered a tuning of the 2.5.7.13.17.19 subgroup, on which it is consistent (see [[No-threes subgroup temperaments#Mercy|mercy temperament]]).
* 23 is about as flat as 11. The chromatic semitone is about half a cent off from 23:22. 31edo could be considered a tuning of the 2.3.5.7.11.23 subgroup, on which it is consistent.
* 27 is quite flat, as it's 3<sup>3</sup> and the error from the meantone fifths accumulates.
* 29 and 31 are both almost critically sharp, and intervals involving them are unlikely to play any major role.
{| class="wikitable"
|-
! Odd overtones in "Mode 16":
| 17
| 19
| 21
| 23
| 25
| 27
| 29
| 31
|-
! …as JI Ratio from 1/1:
| 17/16
| 19/16
| 21/16
| 23/16
| 25/16
| 27/16
| 29/16
| 31/16
|-
! …in cents:
| 105.0
| 297.5
| 470.8
| 628.3
| 772.6
| 905.9
| 1029.6
| 1145.0
|-
! Nearest degree of 31edo:
| 3
| 8
| 12
| 16
| 20
| 23
| 27
| 30
|-
! …in cents:
| 116.1
| 309.7
| 464.5
| 619.4
| 774.2
| 890.3
| 1045.1
| 1161.3
|}
=== Various subsets ===
A large open list of subsets from 31edo that people have named:
* [[31edo modes]]
* [[Strictly proper]] [[Strictly proper 7-tone 31edo scales|7-tone 31edo scales]]
* Interesting (to somebody) [[9-tone 31edo scales]]
* the [[Erose–McClain double mode]]s, which are [[nonoctave]]
* the [[Euler–Fokker genus]] (technically [[JI]] but representable in 31)
* the [[altered pentad]]
* [[diasem]] (2.3.7 subgroup scale; 5 2 5 1 5 2 5 1 5 or 5 1 5 2 5 1 5 2 5 in 31edo)


== Approximation to JI ==
== Approximation to JI ==
Line 1,367: Line 1,215:
{{Harmonics in equal|49|3|1|columns=11|collapsed=true|intervals=integer|title=Approximation of harmonics in 49edt}}
{{Harmonics in equal|49|3|1|columns=11|collapsed=true|intervals=integer|title=Approximation of harmonics in 49edt}}
{{Harmonics in equal|49|3|1|columns=12|start=12|collapsed=true|intervals=integer|title=Approximation of harmonics in 49edt (continued)}}
{{Harmonics in equal|49|3|1|columns=12|start=12|collapsed=true|intervals=integer|title=Approximation of harmonics in 49edt (continued)}}
== Scales ==
* [[Meantone5]]
* [[Meantone7]]
* [[Meantone12]]
=== MOS scales ===
{{main| List of MOS scales in 31edo }}
The fact that 31edo has meantone diatonic and chromatic scales is well-known, but some other [[MOS]]es and MOS chains{{clarify}} are also useful:
* 9\31, the neutral third, generates [[ultrasoft]] [[mosh]] and [[superhard]] [[dicotonic]] MOSes.
* 11\31, the supermajor third or diminished fourth, generates a [[TAMNAMS|parahard]] [[sensoid]] scale with resolution from neutral thirds, sixths, and sevenths to perfect fourths, fifths, and octaves, and a [[semihard]] [[3L&nbsp;8s]] scale with a jagged-but-chromatic feel.
* 12\31 generator generates a [[semihard]] oneirotonic ([[5L&nbsp;3s]]) scale, similar to the 5L&nbsp;3s scale in [[13edo]] but with the 9/8, 5/4, and 7/6 better in tune and with the flat fifth close to [[19/13]].
* A chain of 5\31 whole tones is exceptionally rich in 4:5:7 chords, which are approximated very well in 31edo.
* If you're fond of orwell tetrads (which are also found in 31edo's oneirotonic), you will like the 7\31 (271.0{{c}}) subminor third generator. The [[ultrasoft]] 9-tone orwelloid [[4L&nbsp;5s]] MOS could be treated as a 9-tone well temperament.
* It has close approximations to [[6edf]] (→&nbsp;[[miracle]]) and [[9edf]] (→&nbsp;[[Carlos Alpha]]), fifth-equivalent equal divisions that hit many good JI approximations.
See [[#Rank-2 temperaments]] for a table of MOSes and their temperament interpretations.
=== Harmonic scales ===
31edo approximates Mode 8 of the [[harmonic series]] okay, but many intervals between the harmonics aren't distinguished, most importantly 9/8 (major tone) and 10/9 (minor tone), as 31EDO is a meantone temperament. The interval between the 8th and 11th harmonics is approximated okay, but the intervals between the 11th harmonic and closer harmonics such as the 12th and 9th harmonics are approximated much better. 31edo's closest approximation of 13/8, the neutral sixth, is significantly sharper than just and only vaguely suggests the [[13-limit]].
The steps are: 5 5 4 4 4 3 3 3.
{| class="wikitable"
|-
! Overtones in "Mode 8":
| 8
| 9
| 10
| 11
| 12
| 13
| 14
| 15
| 16
|-
! …as JI Ratio from 1/1:
| 1/1
| 9/8
| 5/4
| 11/8
| 3/2
| 13/8
| 7/4
| 15/8
| 2/1
|-
! …in cents:
| 0
| 203.9
| 386.3
| 551.3
| 702.0
| 840.5
| 968.8
| 1088.3
| 1200.0
|-
! Nearest degree of 31edo:
| 0
| 5
| 10
| 14
| 18
| 22
| 25
| 28
| 31
|-
! …in cents:
| 0
| 193.5
| 387.1
| 541.9
| 696.8
| 851.6
| 967.7
| 1083.9
| 1200.0
|}
In mode 16, the most closely-matched harmonics are the composite ones, 21 and 25. Of the other harmonics:
* 17 is sharp, like 13. In fact, the 17:13 ratio is matched within a tenth of a cent.
* 19 is also sharp, like 13 and 17. The 19:17 ratio is about one cent sharp. 31edo could be considered a tuning of the 2.5.7.13.17.19 subgroup, on which it is consistent (see [[No-threes subgroup temperaments#Mercy|mercy temperament]]).
* 23 is about as flat as 11. The chromatic semitone is about half a cent off from 23:22. 31edo could be considered a tuning of the 2.3.5.7.11.23 subgroup, on which it is consistent.
* 27 is quite flat, as it's 3<sup>3</sup> and the error from the meantone fifths accumulates.
* 29 and 31 are both almost critically sharp, and intervals involving them are unlikely to play any major role.
{| class="wikitable"
|-
! Odd overtones in "Mode 16":
| 17
| 19
| 21
| 23
| 25
| 27
| 29
| 31
|-
! …as JI Ratio from 1/1:
| 17/16
| 19/16
| 21/16
| 23/16
| 25/16
| 27/16
| 29/16
| 31/16
|-
! …in cents:
| 105.0
| 297.5
| 470.8
| 628.3
| 772.6
| 905.9
| 1029.6
| 1145.0
|-
! Nearest degree of 31edo:
| 3
| 8
| 12
| 16
| 20
| 23
| 27
| 30
|-
! …in cents:
| 116.1
| 309.7
| 464.5
| 619.4
| 774.2
| 890.3
| 1045.1
| 1161.3
|}
=== Various subsets ===
A large open list of subsets from 31edo that people have named:
* [[31edo modes]]
* [[Strictly proper]] [[Strictly proper 7-tone 31edo scales|7-tone 31edo scales]]
* Interesting (to somebody) [[9-tone 31edo scales]]
* the [[Erose–McClain double mode]]s, which are [[nonoctave]]
* the [[Euler–Fokker genus]] (technically [[JI]] but representable in 31)
* the [[altered pentad]]
* [[diasem]] (2.3.7 subgroup scale; 5 2 5 1 5 2 5 1 5 or 5 1 5 2 5 1 5 2 5 in 31edo)


== Instruments ==
== Instruments ==