81edt

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← 80edt 81edt 82edt →
Prime factorization 34
Step size 23.4809¢ 
Octave 51\81edt (1197.53¢) (→17\27edt)
Consistency limit 4
Distinct consistency limit 4

81 equal divisions of the tritave, perfect twelfth, or 3rd harmonic (abbreviated 81edt or 81ed3), is a nonoctave tuning system that divides the interval of 3/1 into 81 equal parts of about 23.5 ¢ each. Each step represents a frequency ratio of 31/81, or the 81st root of 3.

Intervals

Steps Cents Approximate ratios
0 0 1/1
1 23.5
2 47 36/35, 37/36, 38/37, 39/38, 40/39
3 70.4
4 93.9 19/18, 37/35, 39/37
5 117.4 31/29
6 140.9 13/12, 38/35
7 164.4 11/10
8 187.8 29/26, 39/35
9 211.3 26/23, 35/31
10 234.8 39/34
11 258.3 36/31
12 281.8 20/17
13 305.3 31/26, 37/31
14 328.7 23/19, 29/24, 35/29
15 352.2 27/22, 38/31
16 375.7 36/29
17 399.2 29/23, 34/27, 39/31
18 422.7 23/18, 37/29
19 446.1 22/17, 31/24, 35/27
20 469.6 21/16, 38/29
21 493.1
22 516.6 27/20, 31/23, 35/26
23 540.1 15/11, 26/19
24 563.5 18/13
25 587
26 610.5 27/19, 37/26
27 634 13/9
28 657.5 19/13
29 680.9 40/27
30 704.4 3/2
31 727.9 32/21, 35/23
32 751.4 17/11, 37/24
33 774.9 36/23
34 798.4 19/12, 27/17
35 821.8 37/23
36 845.3 31/19
37 868.8 33/20, 38/23
38 892.3
39 915.8 17/10, 39/23
40 939.2 31/18
41 962.7
42 986.2 23/13, 30/17
43 1009.7 34/19
44 1033.2 20/11
45 1056.6 35/19
46 1080.1
47 1103.6 17/9, 36/19
48 1127.1 23/12
49 1150.6 33/17, 35/18
50 1174
51 1197.5 2/1
52 1221
53 1244.5 37/18, 39/19
54 1268 27/13
55 1291.5 19/9, 40/19
56 1314.9
57 1338.4 13/6
58 1361.9 11/5
59 1385.4 20/9
60 1408.9
61 1432.3 16/7
62 1455.8
63 1479.3 40/17
64 1502.8 31/13
65 1526.3 29/12
66 1549.7 22/9
67 1573.2
68 1596.7
69 1620.2
70 1643.7 31/12
71 1667.1 34/13
72 1690.6
73 1714.1 35/13
74 1737.6 30/11
75 1761.1 36/13
76 1784.6
77 1808 37/13
78 1831.5
79 1855 35/12, 38/13
80 1878.5
81 1902 3/1

Harmonics

Approximation of harmonics in 81edt
Harmonic 2 3 4 5 6 7 8 9 10 11 12
Error Absolute (¢) -2.5 +0.0 -4.9 +7.9 -2.5 -11.1 -7.4 +0.0 +5.4 +4.8 -4.9
Relative (%) -10.5 +0.0 -21.1 +33.7 -10.5 -47.1 -31.6 +0.0 +23.2 +20.5 -21.1
Steps
(reduced)
51
(51)
81
(0)
102
(21)
119
(38)
132
(51)
143
(62)
153
(72)
162
(0)
170
(8)
177
(15)
183
(21)
Approximation of harmonics in 81edt
Harmonic 13 14 15 16 17 18 19 20 21 22 23
Error Absolute (¢) -2.6 +10.0 +7.9 -9.9 +2.6 -2.5 -2.2 +3.0 -11.1 +2.3 -4.2
Relative (%) -11.2 +42.4 +33.7 -42.1 +10.9 -10.5 -9.2 +12.7 -47.1 +9.9 -17.8
Steps
(reduced)
189
(27)
195
(33)
200
(38)
204
(42)
209
(47)
213
(51)
217
(55)
221
(59)
224
(62)
228
(66)
231
(69)