30edo

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Revision as of 23:24, 27 November 2023 by CompactStar (talk | contribs) (Add both fifths via interval table template – The 680c fifth is almost as acceptable as the 5edo one)
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← 29edo 30edo 31edo →
Prime factorization 2 × 3 × 5
Step size 40 ¢ 
Fifth 18\30 (720 ¢) (→ 3\5)
Semitones (A1:m2) 6:0 (240 ¢ : 0 ¢)
Dual sharp fifth 18\30 (720 ¢) (→ 3\5)
Dual flat fifth 17\30 (680 ¢)
Dual major 2nd 5\30 (200 ¢) (→ 1\6)
Consistency limit 5
Distinct consistency limit 5

30 equal divisions of the octave (30edo) is the tuning system derived by dividing the octave into 30 equal steps of 40 ¢ each.

Theory

Approximation of odd harmonics in 30edo
Harmonic 3 5 7 9 11 13 15 17 19 21 23
Error Absolute (¢) +18.0 +13.7 -8.8 -3.9 +8.7 -0.5 -8.3 +15.0 -17.5 +9.2 +11.7
Relative (%) +45.1 +34.2 -22.1 -9.8 +21.7 -1.3 -20.7 +37.6 -43.8 +23.0 +29.3
Steps
(reduced)
48
(18)
70
(10)
84
(24)
95
(5)
104
(14)
111
(21)
117
(27)
123
(3)
127
(7)
132
(12)
136
(16)

Its patent val is a doubled version of the patent val for 15edo through the 11-limit, so 30 can be viewed as a contorted version of 15. In the 13-limit it supplies the optimal patent val for quindecic temperament.

plot30.png
A plot of the Z function around 30.

However, 5\30 is 200 cents, which is a good (and familiar) approximation for 9/8, and hence 30edo can be viewed inconsistently, as having a 9/1 at 95\30 as well as 96\30.

Instead of the 18\30 fifth of 720 cents, 30edo also makes available a 17\30 fifth of 680 cents. This is an ideal tuning for pelogic (5-limit mavila), which tempers out 135/128. When 30edo is used for pelogic, 5\30 can again be used inconsistently as a 9/8.

Subsets and supersets

30edo has subset edos 1, 2, 3, 5, 6, 10, 15 and it is a largely composite edo.

30edo is the 3rd primorial edo, being the product of first three primes and thus the smallest number with three distinct prime factors. As a corollary, 30edo is the smallest EDO that supports perfectly balanced scales that are minimal and not equally spaced. See the article on perfect balance.

Intervals

Steps Cents Approximate ratios Ups and downs notation
(Dual flat fifth 17\30)
Ups and downs notation
(Dual sharp fifth 18\30)
0 0 1/1 D D
1 40 D♯, E♭♭♭ ^D, ^E♭, ^F♭
2 80 21/20, 22/21, 23/22, 24/23, 25/24 D𝄪, E♭♭ ^^D, ^^E♭, ^^F♭
3 120 14/13 D♯𝄪, E♭ ^3D, v3E, v3F
4 160 11/10, 12/11, 23/21 E vvD♯, vvE, vvF
5 200 E♯, F♭♭♭♭ vD♯, vE, vF
6 240 8/7, 23/20 E𝄪, F♭♭♭ E, F
7 280 13/11, 20/17 E♯𝄪, F♭♭ ^E, ^F, ^G♭
8 320 6/5 E𝄪𝄪, F♭ ^^E, ^^F, ^^G♭
9 360 16/13, 21/17, 26/21 F ^3E, ^3F, v3G
10 400 F♯, G♭♭♭ vvE♯, vvF♯, vvG
11 440 22/17 F𝄪, G♭♭ vE♯, vF♯, vG
12 480 21/16 F♯𝄪, G♭ G
13 520 19/14, 23/17 G ^G, ^A♭
14 560 11/8, 25/18 G♯, A♭♭♭ ^^G, ^^A♭
15 600 17/12, 24/17 G𝄪, A♭♭ ^3G, v3A
16 640 16/11 G♯𝄪, A♭ vvG♯, vvA
17 680 A vG♯, vA
18 720 A♯, B♭♭♭ A
19 760 17/11 A𝄪, B♭♭ ^A, ^B♭, ^C♭
20 800 A♯𝄪, B♭ ^^A, ^^B♭, ^^C♭
21 840 13/8, 21/13 B ^3A, v3B, v3C
22 880 5/3 B♯, C♭♭♭♭ vvA♯, vvB, vvC
23 920 17/10, 22/13 B𝄪, C♭♭♭ vA♯, vB, vC
24 960 7/4 B♯𝄪, C♭♭ B, C
25 1000 B𝄪𝄪, C♭ ^B, ^C, ^D♭
26 1040 11/6, 20/11 C ^^B, ^^C, ^^D♭
27 1080 13/7 C♯, D♭♭♭ ^3B, ^3C, v3D
28 1120 21/11, 23/12 C𝄪, D♭♭ vvB♯, vvC♯, vvD
29 1160 C♯𝄪, D♭ vB♯, vC♯, vD
30 1200 2/1 D D

Rank-2 temperaments

As 30edo is largely composite, only 7, 11 and 13 steps create MOS scales that cover every interval using one period per octave.

7/30 produces Lovecraft, in which 2 generators is a moderately sharp 11/8, 3 a near perfect 13/8 and 5 the familiar mildly flat 9/8 from 12edo, creating the possibility of ignoring the 3rd & 5th entirely to use those harmonics as the primary building blocks of harmony in a similar way to orgone.

11 produces a flat sensi scale. 13 is an excellent higher order Mavila tuning that functions the closest to the familiar diatonic scale you can get in this edo.

MOS scales

Commas

30 EDO tempers out the following commas. (Note: This assumes the val 30 48 70 84 104 111].)

Prime
Limit
Ratio[1] Monzo Cents Color name Name(s)
3 256/243 [8 -5 90.22 Sawa Limma, Pythagorean minor sedond
5 250/243 [1 -5 3 49.17 Triyo Maximal diesis, Porcupine comma
5 128/125 [7 0 -3 41.06 Trigu Diesis, augmented comma
5 15625/15552 [-6 -5 6 8.11 Tribiyo Kleisma, semicomma majeur
7 1029/1000 [-3 1 -3 3 49.49 Trizogu Keega
7 49/48 [-4 -1 0 2 35.70 Zozo Slendro diesis
7 64/63 [6 -2 0 -1 27.26 Ru Septimal comma, Archytas' comma, Leipziger Komma
7 64827/64000 [-9 3 -3 4 22.23 Laquadzo-atrigu Squalentine
7 875/864 [-5 -3 3 1 21.90 Zotriyo Keema
7 126/125 [1 2 -3 1 13.79 Zotrigu Septimal semicomma, Starling comma
7 4000/3969 [5 -4 3 -2 13.47 Rurutriyo Octagar
7 1029/1024 [-10 1 0 3 8.43 Latrizo Gamelisma
7 6144/6125 [11 1 -3 -2 5.36 Saruru-atrigu Porwell
7 (12 digits) [-4 6 -6 3 0.33 Trizogugu Landscape comma
11 100/99 [2 -2 2 0 -1 17.40 Luyoyo Ptolemisma
11 121/120 [-3 -1 -1 0 2 14.37 Lologu Biyatisma
11 176/175 [4 0 -2 -1 1 9.86 Lorugugu Valinorsma
11 65536/65219 [16 0 0 -2 -3 8.39 Satrilu-aruru Orgonisma
11 385/384 [-7 -1 1 1 1 4.50 Lozoyo Keenanisma
11 441/440 [-3 2 -1 2 -1 3.93 Luzozogu Werckisma
11 4000/3993 [5 -1 3 0 -3 3.03 Triluyo Wizardharry
11 3025/3024 [-4 -3 2 -1 2 0.57 Loloruyoyo Lehmerisma
  1. Ratios longer than 10 digits are presented by placeholders with informative hints

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