27edo

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Revision as of 02:40, 12 November 2026 by Ground (talk | contribs) (Created page with "27edo, or 27 equal divisions of the octave, is the equal tuning with a step size of (1200/27) ≈ 44.4¢, 27 of which stack to the perfect octave 2/1. It is best known as a Superpyth tuning alongside 22edo with a distinct sharp tendency in the 7-limit, and approximating prime 13 well instead of 11. == Theory == {{Harmonics in ED|27|53|0}} Useful aberrismic scales in 27edo include blackdye, pinedye, and their mutual superset trackdye. === Ground's chord...")
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27edo, or 27 equal divisions of the octave, is the equal tuning with a step size of (1200/27) ≈ 44.4¢, 27 of which stack to the perfect octave 2/1. It is best known as a Superpyth tuning alongside 22edo with a distinct sharp tendency in the 7-limit, and approximating prime 13 well instead of 11.

Theory

Approximation of prime harmonics in 27edo
Harmonic 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53
Error Absolute (¢) 0.0 +9.2 +13.7 +9.0 -18.0 +3.9 -16.1 +13.6 -6.1 -7.4 +10.5 +15.3 +15.4 +21.8 +1.2 +15.4
Relative (%) 0.0 +20.6 +30.8 +20.1 -40.5 +8.8 -36.1 +30.6 -13.6 -16.5 +23.7 +34.5 +34.6 +49.1 +2.6 +34.6
Steps
(reduced)
27
(0)
43
(16)
63
(9)
76
(22)
93
(12)
100
(19)
110
(2)
115
(7)
122
(14)
131
(23)
134
(26)
141
(6)
145
(10)
147
(12)
150
(15)
155
(20)

Useful aberrismic scales in 27edo include blackdye, pinedye, and their mutual superset trackdye.

Ground's chord table

This table uses ground's interval name shorthand.

fif
17\27 (sj
1inv)
sensic
simic
sensic
taphric
(um
2inv)
16\27 um m n j sj
15\27 tim tm dm dj tj tlj
14\27 classic
dim.
13\27 otonal
dim.

Multiples

54edo

Approximation of prime harmonics in 54edo
Harmonic 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53
Error Absolute (¢) 0.0 +9.2 -8.5 +9.0 +4.2 +3.9 +6.2 -8.6 -6.1 -7.4 +10.5 -6.9 -6.8 -0.4 +1.2 -6.8
Relative (%) 0.0 +41.2 -38.4 +40.3 +19.1 +17.6 +27.7 -38.8 -27.2 -33.1 +47.3 -31.0 -30.8 -1.8 +5.2 -30.8
Steps
(reduced)
54
(0)
86
(32)
125
(17)
152
(44)
187
(25)
200
(38)
221
(5)
229
(13)
244
(28)
262
(46)
268
(52)
281
(11)
289
(19)
293
(23)
300
(30)
309
(39)

81edo

Approximation of prime harmonics in 81edo
Harmonic 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53
Error Absolute (¢) 0.0 -5.7 -1.1 -5.9 -3.2 +3.9 -1.3 -1.2 -6.1 -7.4 -4.3 +0.5 +0.6 +7.0 +1.2 +0.6
Relative (%) 0.0 -38.2 -7.6 -39.6 -21.4 +26.4 -8.4 -8.2 -40.9 -49.6 -29.0 +3.4 +3.8 +47.3 +7.8 +3.8
Steps
(reduced)
81
(0)
128
(47)
188
(26)
227
(65)
280
(37)
300
(57)
331
(7)
344
(20)
366
(42)
393
(69)
401
(77)
422
(17)
434
(29)
440
(35)
450
(45)
464
(59)