31edo

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← 30edo 31edo 32edo →
Prime factorization 31 (prime)
Step size 38.7097 ¢ 
Fifth 18\31 (696.774 ¢)
Semitones (A1:m2) 2:3 (77.42 ¢ : 116.1 ¢)
Consistency limit 11
Distinct consistency limit 7

Thirty-one tone equal temperament, also called 31-tET, 31-EDO, 31-et, or tricesimoprimal meantone temperament, is the scale derived by dividing the octave into 31 equally large steps. The term Tricesimoprimal was first used by Adriaan Fokker.

Basic theory

prime 2 prime 3 prime 5 prime 7 prime 11 prime 13 prime 17 prime 19 prime 23
Error absolute (¢) 0 -5.18 +0.8 -1.1 -9.4 +11.1 +11.2 +12.2 -8.9
relative (%) 0 -13 +2 -3 -24 +29 +29 +31 -23
nearest edomapping 31 18 10 25 14 22 3 8 16
fifthspan 0 +1 +4 +10 -13 +15 -5 -3 -6

Each step is equivalent to a frequency ratio of the 31st root of 2, or 38.71 cents. 31's perfect fifth is flat of the just interval 3/2 (over five cents), as befits a tuning supporting meantone, but the major third is less than a cent sharp (of just 5/4), making it slightly sharp of quarter-comma meantone. 31's approximation of 7/4, a cent flat, is also very close to just. It is a very tone-efficient melodic approximation of the 11-limit, although the fact that it equates 14/11 with 9/7, and 11/8 with 15/11, may be too off for some. Many 7-limit JI scales are well-approximated in 31 (with tempering, of course).

Because of these near-just values and because the 11th harmonic is almost twice as flat as the 3rd harmonic, 31-et is relatively quite accurate and is the 6th zeta integral edo, the 7th zeta gap edo, a zeta peak edo and a zeta peak integer edo.

31edo's 5\31 neutral third generator generates mosh and dicoid MOSes. Its 12\31 generator generates an oneirotonic scale, similar to the 5L 3s scale in 13edo but with the 9/8 and 5/4 better in tune.

One step of 31edo, measuring about 38.7¢, is called a diesis because it stands in for several intervals called "dieses" (such as 128/125 and 648/625) which are tempered out in 12edo. The diesis is a defining sound of 31edo; when it does not appear directly in a scale, it often shows up as the difference between two or more intervals of a similar size. The diesis is demonstrated in SpiralProgressions. Zhea Erose's 31edo music uses the interval frequently.

31edo is the 11th prime edo, following 29edo and coming before 37edo.

Intervals

Degree Cents Approximate Ratios Ups and Downs Notation Extended pythagorean notation
0 0.00 1/1 P1 perfect unison D P1 perfect unison D
1 38.71 45/44, 49/48, 46/45, 128/125, 36/35 ^1, d2 up-unison, dim 2nd ^D, Ebb d2 dim 2nd Ebb
2 77.42 25/24, 21/20, 22/21, 23/22 A1, vm2 aug 1sn, downminor 2nd D#, vEb A1 aug 1sn D#
3 116.13 15/14, 16/15 m2 minor 2nd Eb m2 minor 2nd Eb
4 154.84 12/11, 11/10, 35/32 ~2 mid 2nd vE AA1, dd3 double-aug 1sn, double-dim 3rd Dx, Fbb
5 193.55 9/8, 10/9, 19/17, 28/25 M2 major 2nd E M2 major 2nd E
6 232.26 8/7, 144/125 ^M2 upmajor 2nd ^E d3 dim 3rd Fb
7 270.97 7/6, 75/64 vm3 downminor 3rd vF A2 aug 2nd E#
8 309.68 6/5, 25/21 m3 minor 3rd F m3 minor 3rd F
9 348.39 11/9, 27/22, 16/13, 60/49, 49/40 ~3 mid 3rd ^F AA2, dd4 double-aug 2nd, double-dim 4th Ex, Gbb
10 387.10 5/4 M3 major 3rd F# M3 major 3rd F#
11 425.81 9/7, 14/11, 23/18, 32/25 ^M3 upmajor 3rd ^F# d4 dim 4th Gb
12 464.52 21/16, 13/10, 17/13, 125/96 v4 down-4th vG A3 aug 3rd Fx
13 503.23 4/3 P4 perfect 4th G P4 perfect 4th G
14 541.94 11/8, 15/11, 26/19 ^4, ~4 up-4th, mid 4th ^G AA3, dd5 double-aug 3rd, double-dim 5th Fx#, Abb
15 580.65 7/5, 45/32, 25/18 A4, vd5 aug 4th, downdim 5th G#, vAb A4 aug 4th G#
16 619.35 10/7, 64/45, 36/25 ^A4, d5 upaug 4th, dim 5th ^G#, Ab d5 dim 5th Ab
17 658.06 16/11, 22/15, 19/13 v5, ~5 down-5th, mid 5th vA AA4, dd6 double-aug 4th, double-dim 6th Gx, Bbbb
18 696.77 3/2 P5 perfect 5th A P5 perfect 5th A
19 735.48 32/21, 20/13, 26/17, 192/125 ^5 up-5th ^A d6 dim 6th Bbb
20 774.19 14/9, 11/7, 25/16 vm6 downminor 6th vBb A5 aug 5th A#
21 812.90 8/5 m6 minor 6th Bb m6 minor 6th Bb
22 851.61 18/11, 44/27, 13/8, 49/30, 80/49 ~6 mid 6th vB AA5, dd7 double-aug 5th, double-dim 7th Ax, Cbb
23 890.32 5/3, 42/25 M6 major 6th B M6 major 6th B
24 929.03 12/7, 128/75 ^M6 upmajor 6th ^B d7 dim 7th Cb
25 967.74 7/4, 125/72 vm7 downminor 7th vC A6 aug 6th B#
26 1006.45 16/9, 9/5, 34/19, 25/14 m7 minor 7th C m7 minor 7th C
27 1045.16 11/6, 20/11, 64/35 ~7 mid 7th ^C AA6, dd8 double-aug 6th, double-dim 8ve Bx, Dbb
28 1083.87 28/15, 15/8 M7 major 7th C# M7 major 7th C#
29 1122.58 48/25, 40/21, 21/11, 44/23 ^M7 upmajor 7th ^C# d8 dim 8ve Db
30 1161.29 88/45, 96/49, 45/23, 125/64, 35/18 v8 down-8ve vD A7 aug 7th Cx
31 1200.00 2/1 P8 perfect 8ve D P8 perfect 8ve D

Combining ups and downs notation with color notation, qualities can be loosely associated with colors:

quality color name monzo format examples
downminor zo {a, b, 0, 1} 7/6, 7/4
minor fourthward wa {a, b}, b < -1 32/27, 16/9
" gu {a, b, -1} 6/5, 9/5
mid ilo {a, b, 0, 0, 1} 11/9, 11/6
" lu {a, b, 0, 0, -1} 12/11, 18/11
major yo {a, b, 1} 5/4, 5/3
" fifthward wa {a, b}, b > 1 9/8, 27/16
upmajor ru {a, b, 0, -1} 9/7, 12/7

All 31edo chords can be named using ups and downs. Alterations are always enclosed in parentheses, additions never are. An up, down or mid immediately after the chord root affects the 3rd, 6th, 7th, and/or the 11th (every other note of a stacked-3rds chord 6-1-3-5-7-9-11-13). Here are the zo, gu, ilo, yo and ru triads:

color of the 3rd JI chord edosteps notes of C chord written name spoken name
zo 6:7:9 0-7-18 C vEb G Cvm C downminor
gu 10:12:15 0-8-18 C Eb G Cm C minor
ilo 18:22:27 0-9-18 C vE G C~ C mid
yo 4:5:6 0-10-18 C E G C C major or C
ru 14:18:21 0-11-18 C ^E G C^ C upmajor or C up

For a more complete list of chords, see Ups and Downs Notation - Chords and Chord Progressions.

Notations

From the appendix to The Sagittal Songbook by Jacob A. Barton, a diagram of how to notate 31-EDO in the Revo flavor of Sagittal:

Just approximation

Selected just intervals

15-odd-limit interval mappings

The following table shows how 15-odd-limit intervals are represented in 31edo. Prime harmonics are in bold; inconsistent intervals are in italic.

Direct mapping (even if inconsistent)
Interval, complement Error (abs, ¢)
5/4, 8/5 0.783
11/9, 18/11 0.979
8/7, 7/4 1.084
7/5, 10/7 1.867
15/14, 28/15 3.314
7/6, 12/7 4.097
12/11, 11/6 4.202
16/15, 15/8 4.398
15/11, 22/15 4.985
4/3, 3/2 5.181
6/5, 5/3 5.964
14/11, 11/7 8.298
9/7, 14/9 9.278
11/8, 16/11 9.382
11/10, 20/11 10.166
13/10, 20/13 10.302
9/8, 16/9 10.362
16/13, 13/8 11.085
10/9, 9/5 11.145
14/13, 13/7 12.169
15/13, 26/15 15.483
13/12, 24/13 16.266
18/13, 13/9 17.263
13/11, 22/13 18.242
Patent val mapping
Interval, complement Error (abs, ¢)
5/4, 8/5 0.783
11/9, 18/11 0.979
8/7, 7/4 1.084
7/5, 10/7 1.867
15/14, 28/15 3.314
7/6, 12/7 4.097
12/11, 11/6 4.202
16/15, 15/8 4.398
15/11, 22/15 4.985
4/3, 3/2 5.181
6/5, 5/3 5.964
14/11, 11/7 8.298
9/7, 14/9 9.278
11/8, 16/11 9.382
11/10, 20/11 10.166
13/10, 20/13 10.302
9/8, 16/9 10.362
16/13, 13/8 11.085
10/9, 9/5 11.145
14/13, 13/7 12.169
15/13, 26/15 15.483
13/12, 24/13 16.266
13/11, 22/13 20.468
18/13, 13/9 21.447

Selected 19-limit intervals

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Temperament measures

The following table shows TE temperament measures (RMS normalized by the rank) of 31et.

3-limit 5-limit 7-limit 11-limit 13-limit
Octave stretch (¢) +1.63 +0.98 +0.83 +1.21 +0.50
Error absolute (¢) 1.64 1.63 1.43 1.49 2.07
relative (%) 4.22 4.20 3.70 3.84 5.35
  • 31et has a lower relative error than any previous ETs in all harmonic limits from 7 to 31.

Relationship to 12-edo

Whereas 12-edo has a circle of twelve 5ths, 31-edo has a spiral of twelve 5ths (since 18\31 is on the 7\12 kite in the scale tree). This spiral of 5th shows 31-edo in a 12-edo-friendly format. Excellent for introducing 31-edo to musicians unfamiliar with microtonal music. The two innermost and two outermost intervals on the spiral are duplicates.

31edo can be notated with a seperate semi/sesqui sharp/flat chain (like 17edo), with its own enharmonic circle of fifths.

MOS scales

Generator Cents MOSes
2\31 77.42 1L 14s
15L 1s
3\31 116.13 1L 8s
1L 9s
10L 1s
10L 11s
4\31 154.84 1L 6s
7L 1s
8L 7s
8L 15s
5\31 193.55 1L 5s
6L 7s
6L 13s
6L 19s
6\31 232.26 1L 4s
5L 6s
5L 11s
5L 16s
5L 21s
7\31 270.97 4L 1s
4L 5s
9L 4s
9L 13s
8\31 309.68 4L 3s
4L 7s
4L 11s
4L 15s
9\31 348.39 3L 4s
7L 3s
7L 10s
7L 17s
10\31 387.10 3L 7s
3L 10s
3L 13s
3L 16s
3L 19s
3L 22s
3L 25s
11\31 425.81 3L 2s
3L 5s
3L 8s
3L 11s
14L 3s
12\31 464.52 3L 2s
5L 3s
5L 8s
13L 5s
13\31 503.23 2L 3s
5L 2s
7L 5s
12L 7s
14\31 541.94 2L 5s
2L 7s
9L 2s
11L 9s
15\31 580.65 2L 3s
2L 5s
2L 7s
2L 9s
2L 11s
2L 13s
2L 15s
2L 17s
2L 19s

As a regular temperament

31edo represents a record in Pepper ambiguity in the 7-, 9- and 11-odd-limit, which it is consistent through. In the 13-limit it doesn't do as well, but is the optimal patent val for the rank five temperament tempering out the 13-limit comma 66/65, which equates 6/5 and 13/11. It also provides the optimal patent val for mohajira, squares and casablanca in the 11-limit and huygens/meantone, squares, winston, lupercalia and nightengale in the 13-limit.

Commas

31 EDO tempers out the following commas. (Note: This assumes the val 31 49 72 87 107 115], comma values rounded to 5 significant digits.)

Prime
limit
Ratio[1] Monzo Cents Color name Name(s)
5 (16 digits) [-25 7 6 31.567 Lala-tribiyo Ampersand
5 81/80 [-4 4 -1 21.506 Gu Syntonic comma, Didymos comma, meantone comma
5 (12 digits) [17 1 -8 11.445 Saquadbigu Würschmidt comma
5 (14 digits) [-21 3 7 10.061 Lasepyo Semicomma, Fokker comma
5 (24 digits) [38 -2 -15 1.3843 Sasa-quintrigu Hemithirds comma
7 (18 digits) [-10 7 8 -7 22.413 Lasepru-aquadbiyo Blackjackisma
7 64827/64000 [-9 3 -3 4 22.227 Laquadzo-atrigu Squalentine
7 2430/2401 [1 5 1 -4 20.785 Quadru-ayo Nuwell
7 50421/50000 [-4 1 -5 5 14.516 Quinzogu Trimyna
7 126/125 [1 2 -3 1 13.795 Zotrigu Septimal semicomma, Starling comma
7 1728/1715 [6 3 -1 -3 13.074 Trizo-agu Orwellisma, Orwell comma
7 1029/1024 [-10 1 0 3 8.4327 Latrizo Gamelisma
7 225/224 [-5 2 2 -1 7.7115 Ruyoyo Septimal kleisma, Marvel comma
7 16875/16807 [0 3 4 -5 6.9903 Quinru-aquadyo Mirkwai
7 3136/3125 [6 0 -5 2 6.0832 Zozoquingu Hemimean
7 6144/6125 [11 1 -3 -2 5.3621 Sarurutrigu Porwell
7 (18 digits) [-26 -1 1 9 3.7919 Latritrizo-ayo Wadisma
7 65625/65536 [-16 1 5 1 2.3495 Lazoquinyo Horwell
7 (12 digits) [-11 2 7 -3 1.6283 Latriru-asepyo Meter
7 2401/2400 [-5 -1 -2 4 0.72120 Bizozogu Breedsma
11 99/98 [-1 2 0 -2 1 17.576 Loruru Mothwellsma
11 121/120 [-3 -1 -1 0 2 14.367 Lologu Biyatisma
11 176/175 [4 0 -2 -1 1 9.8646 Lorugugu Valinorsma
11 243/242 [-1 5 0 0 -2 7.1391 Lulu Rastma
11 385/384 [-7 -1 1 1 1 4.5026 Lozoyo Keenanisma
11 441/440 [-3 2 -1 2 -1 3.9302 Luzozogu Werckisma
11 540/539 [2 3 1 -2 -1 3.2090 Lururuyo Swetisma
11 3025/3024 [-4 -3 2 -1 2 0.57240 Loloruyoyo Lehmerisma
  1. Ratios longer than 10 digits are presented by placeholders with informative hints

Rank-2 temperaments

List of 31et rank two temperaments by badness

List of edo-distinct 31et rank two temperaments

Generator Cents Temperaments Pergen
1\31 38.71 Slender (P8, P4/13)
2\31 77.42 Valentine/Lupercalia (P8, P5/9)
3\31 116.13 Miracle (P8, P5/6)
4\31 154.84 Nusecond (P8, P11/11)
5\31 193.55 Luna/Hemithirds/Hemiwürschmidt (P8, WWP4/15)
6\31 232.26 Mothra/Mosura (P8, P5/3)
7\31 270.97 Orwell/Orson/Winston (P8, P12/7)
8\31 309.68 Myna (P8, WWP5/10)
9\31 348.39 Vicentino/Mohajira/Migration (P8, P5/2)
10\31 387.10 Würschmidt/Worschmidt (P8, WWP5/8)
11\31 425.81 Squares/Sentinel (P8, P11/4)
12\31 464.52 A-Team/Semisept (P8, M9/3)
13\31 503.23 Meantone/Meanpop (P8, P5)
14\31 541.94 Casablanca/Cypress/Oracle (P8, W5P4/12)
15\31 580.65 Tritonic/Tritoni (P8, WWP4/5)

Scales

Harmonic Scale

31edo approximates Mode 8 of the harmonic series O.K., 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 O.K., but the intervals between the 11th harmonic and closer harmonics such as the 12th and 9th harmonics are approximated even better. 31's version of 13/8 is quite wide and only vaguely suggests the 13-limit.

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.
  • 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 3^3 and the error from the meantone fifths accumulates.
  • 29 and 31 are both very sharp, and intervals involving them are unlikely to play any major role.
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 Modes

A large open list of modes (subsets) from 31edo that people have named: 31edo modes. Strictly proper 7-note 31edo scales in the sense of David Rothenberg. Interesting (to somebody) 9-note 31edo scales. See also 31edo MOS scales. Some of the popular ones:

  • 31-tone major: 5 5 3 5 5 5 3
  • Meantone[12] (Eb-G#): 2 3 3 2 3 2 3 2 3 3 2 3
  • Harmonic scale 8: 5 5 4 4 4 3 3 3
  • the Euler-Fokker genera (technically JI but representable in 31)
Some 31 tone equal modes
2 3 3 2 3 2 3 2 3 3 2 3 Meantone Chromatic (53/220-comma)
5 5 3 5 5 5 3 Thirty-one tone Major, Intense Diatonic Lydian, M.Ionian
5 3 5 5 3 5 5 Thirty-one tone Natural Minor, Intense Diatonic Hypodorian, Aeolian
5 3 5 5 5 5 3 Thirty-one tone Melodic Minor
5 3 5 5 3 7 3 Thirty-one tone Harmonic Minor
5 5 3 5 3 7 3 Thirty-one tone Harmonic Major
5 5 3 5 3 5 5 Thirty-one tone Major-Minor
5 8 5 13 Genus primum
10 3 5 5 5 3 Genus secundum
8 2 8 3 7 3 Genus tertium
10 10 10 1 Genus quartum
5 7 6 7 5 1 Genus quintum
4 6 2 6 4 3 3 3 Genus sextum
4 6 5 6 4 6 Genus septimum
6 6 6 1 6 6 Genus octavum
4 6 9 6 4 2 Genus nonum
13 6 6 6 Genus decimum
5 5 3 5 5 3 2 3 Genus diatonicum
3 5 2 3 5 3 2 5 3 Genus chromaticum
5 5 2 1 5 5 2 3 3 Genus diatonicum cum septimis
3 4 3 3 2 1 4 1 4 1 2 3 Genus enharmonicum vocale
2 2 4 2 2 3 3 3 1 3 3 3 Genus enharmonicum instrumentale
3 2 3 2 3 2 3 3 2 3 2 3 Genus diatonico-chromaticum
5 2 1 2 5 3 2 1 4 1 2 3 Genus bichromaticum
4 4 5 4 4 5 5 Neutral Diatonic Mixolydian
4 5 4 4 5 5 4 Neutral Diatonic Lydian
5 4 4 5 5 4 4 Neutral Diatonic Phrygian
4 4 5 5 4 4 5 Neutral Diatonic Dorian
4 5 5 4 4 5 4 Neutral Diatonic Hypolydian
5 5 4 4 5 4 4 Neutral Diatonic Hypophrygian
5 4 4 5 4 4 5 Neutral Diatonic Hypodorian
4 5 4 4 5 4 5 Neutral Mixolydian
5 4 4 5 4 5 4 Neutral Lydian
4 4 5 4 5 4 5 Neutral Phrygian
4 5 4 5 4 5 4 Neutral Dorian
5 4 5 4 5 4 4 Neutral Hypolydian
4 5 4 5 4 4 5 Neutral Hypophrygian
5 4 5 4 4 5 4 Neutral Hypodorian
2 2 9 2 2 9 5 Hemiolic Chromatic Mixolydian
2 9 2 2 9 5 2 Hemiolic Chromatic Lydian
9 2 2 9 5 2 2 Hemiolic Chromatic Phrygian
2 2 9 5 2 2 9 Hemiolic Chromatic Dorian
2 9 5 2 2 9 2 Hemiolic Chromatic Hypolydian
9 5 2 2 9 2 2 Hemiolic Chromatic Hypophrygian
5 2 2 9 2 2 9 Hemiolic Chromatic Hypodorian
2 3 8 2 3 8 5 Ratio 2:3 Chromatic Mixolydian
3 8 2 3 8 5 2 Ratio 2:3 Chromatic Lydian
8 2 3 8 5 2 3 Ratio 2:3 Chromatic Phrygian
2 3 8 5 2 3 8 Ratio 2:3 Chromatic Dorian
3 8 5 2 3 8 2 Ratio 2:3 Chromatic Hypolydian
8 5 2 3 8 2 3 Ratio 2:3 Chromatic Hypophrygian
5 2 3 8 2 3 8 Ratio 2:3 Chromatic Hypodorian
3 5 5 3 5 5 5 Intense Diatonic Mixolydian, M.Locrian
5 3 5 5 5 3 5 Intense Diatonic Phrygian, M.Dorian
3 5 5 5 3 5 5 Intense Diatonic Dorian, M.Phrygian
5 5 5 3 5 5 3 Intense Diatonic Hypolydian, M.Lydian
5 5 3 5 5 3 5 Intense Diatonic Hypophrygian, M.Mixolydian
2 5 6 2 5 6 5 Soft Diatonic Mixolydian
5 6 2 5 6 5 2 Soft Diatonic Lydian
6 2 5 6 5 2 5 Soft Diatonic Phrygian
2 5 6 5 2 5 6 Soft Diatonic Dorian
5 6 5 2 5 6 2 Soft Diatonic Hypolydian
6 5 2 5 6 2 5 Soft Diatonic Hypophrygian
5 2 5 6 2 5 6 Soft Diatonic Hypodorian
1 2 10 1 2 10 5 Enharmonic Mixolydian
2 10 1 2 10 5 1 Enharmonic Lydian
10 1 2 10 5 1 2 Enharmonic Phrygian
1 2 10 5 1 2 10 Enharmonic Dorian
2 10 5 1 2 10 1 Enharmonic Hypolydian
10 5 1 2 10 1 2 Enharmonic Hypophrygian
5 1 2 10 1 2 10 Enharmonic Hypodorian
6 6 7 6 6 Quasi-equal Pentatonic
3 2 2 3 3 2 3 3 2 2 3 3 Fokker 12-tone
5 3 5 3 5 2 5 3 Modus conjunctus
3 5 2 5 3 5 3 5 Octatonic
3 3 4 3 5 3 4 3 3 Hahn symmetric pentachordal
3 4 3 3 5 3 4 3 3 Hahn pentachordal
4 4 2 5 3 3 4 3 3 Hahn Nonatonic
5 1 5 1 5 1 5 1 5 1 1 de Vries 11-tone
4 1 4 4 4 1 4 4 1 4 Breed 10-tone
4 2 4 2 4 2 4 3 3 3 Lumma Decatonic
5 3 3 3 3 5 3 3 3 Rothenberg Generalized Diatonic
5 2 6 5 2 5 6 "Septimal" Natural Minor
4 3 4 3 4 3 4 3 3 Thirty-one tone Orwell
2 5 2 2 5 2 2 2 5 2 2 Secor Sentinel

Trivia

31edo is close to a circle made by stacking 31 pure 17/13 subfourths. A circle of 31 pure 17/13's closes with an error of only 2.74 cents (relative error 7.1%).

Music

By Cam Taylor

By Johann alias Circular17

By Zhea Erose

See Also

Pedagogy

The MicroPedagogyCollective is currently at work producing demonstrative material which will encourage and enable more people to learn this system. There have been two ThirtyOneToneSinginCamps as well.

See also: 31edo solfege, Tricesimoprimal Tetrachordal Tesseract, Pentachords of 31edo.

Books

External image: http://ronsword.com/images/TSG_sm.jpg [dead link]

WARNING: MediaWiki doesn't have very good support for external images.
Furthermore, since external images can break, we recommend that you replace the above with a local copy of the image.

Sword, Ronald. "Tricesimoprimal Scales for Guitar." IAAA Press, UK-USA. First Ed: March 2009. [dead link] - A comprehensive approach to 31-EDO and all the families associated for Guitar. Features over 300 scale charts / scale examples.

Articles

Videos

Software