87ed4

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← 85ed4 87ed4 89ed4 →
Prime factorization 3 × 29
Step size 27.5862¢ 
Octave 44\87ed4 (1213.79¢)
Twelfth 69\87ed4 (1903.45¢) (→23\29ed4)
Consistency limit 1
Distinct consistency limit 1

87 equal divisions of the 4th harmonic (abbreviated 87ed4) is a nonoctave tuning system that divides the interval of 4/1 into 87 equal parts of about 27.6 ¢ each. Each step represents a frequency ratio of 41/87, or the 87th root of 4.

Intervals

Steps Cents Approximate ratios
0 0 1/1
1 27.6
2 55.2 31/30
3 82.8 22/21
4 110.3
5 137.9
6 165.5
7 193.1 19/17
8 220.7 25/22
9 248.3 15/13
10 275.9 27/23, 41/35
11 303.4 25/21, 31/26, 37/31
12 331 23/19
13 358.6
14 386.2
15 413.8
16 441.4
17 469
18 496.6
19 524.1 23/17
20 551.7
21 579.3
22 606.9 27/19
23 634.5 13/9
24 662.1 22/15
25 689.7
26 717.2
27 744.8
28 772.4 39/25
29 800 27/17
30 827.6 21/13
31 855.2 41/25
32 882.8 5/3
33 910.3 22/13
34 937.9
35 965.5
36 993.1 39/22
37 1020.7
38 1048.3
39 1075.9 41/22
40 1103.4 17/9
41 1131 25/13
42 1158.6 41/21
43 1186.2
44 1213.8
45 1241.4
46 1269
47 1296.6
48 1324.1
49 1351.7
50 1379.3
51 1406.9
52 1434.5
53 1462.1
54 1489.7
55 1517.2
56 1544.8 22/9
57 1572.4
58 1600
59 1627.6
60 1655.2 13/5
61 1682.8 37/14
62 1710.3
63 1737.9 41/15
64 1765.5
65 1793.1
66 1820.7
67 1848.3
68 1875.9
69 1903.4 3/1
70 1931
71 1958.6 31/10
72 1986.2 41/13
73 2013.8
74 2041.4
75 2069
76 2096.6
77 2124.1
78 2151.7
79 2179.3
80 2206.9
81 2234.5
82 2262.1
83 2289.7
84 2317.2
85 2344.8
86 2372.4
87 2400

Harmonics

Approximation of harmonics in 87ed4
Harmonic 2 3 4 5 6 7 8 9 10 11 12
Error Absolute (¢) +13.8 +1.5 +0.0 -0.1 -12.3 -3.3 +13.8 +3.0 +13.7 -13.4 +1.5
Relative (%) +50.0 +5.4 +0.0 -0.4 -44.6 -12.0 +50.0 +10.8 +49.6 -48.5 +5.4
Steps
(reduced)
44
(44)
69
(69)
87
(0)
101
(14)
112
(25)
122
(35)
131
(44)
138
(51)
145
(58)
150
(63)
156
(69)
Approximation of harmonics in 87ed4
Harmonic 13 14 15 16 17 18 19 20 21 22 23
Error Absolute (¢) +0.9 +10.5 +1.4 +0.0 +5.4 -10.8 +5.9 -0.1 -1.8 +0.4 +6.2
Relative (%) +3.1 +38.0 +5.0 +0.0 +19.5 -39.2 +21.5 -0.4 -6.6 +1.5 +22.5
Steps
(reduced)
161
(74)
166
(79)
170
(83)
174
(0)
178
(4)
181
(7)
185
(11)
188
(14)
191
(17)
194
(20)
197
(23)