28ed7/4

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← 27ed7/428ed7/429ed7/4 →
Prime factorization 22 × 7
Step size 34.6009¢ 
Octave 35\28ed7/4 (1211.03¢) (→5\4ed7/4)
Twelfth 55\28ed7/4 (1903.05¢)
(semiconvergent)
Consistency limit 3
Distinct consistency limit 3

28 equal divisions of 7/4 (abbreviated 28ed7/4) is a nonoctave tuning system that divides the interval of 7/4 into 28 equal parts of about 34.6 ¢ each. Each step represents a frequency ratio of (7/4)1/28, or the 28th root of 7/4.

Intervals

Steps Cents Approximate Ratios
0 0 1/1
1 34.601
2 69.202 23/22, 25/24, 27/26
3 103.803 18/17
4 138.404 14/13
5 173.005 21/19
6 207.606 17/15, 26/23
7 242.206
8 276.807 27/23
9 311.408 6/5
10 346.009 11/9, 17/14, 27/22
11 380.61 5/4, 26/21
12 415.211 14/11, 23/18
13 449.812 22/17
14 484.413
15 519.014 19/14, 23/17
16 553.615 26/19
17 588.216
18 622.817
19 657.418 19/13, 22/15
20 692.019 3/2
21 726.619 26/17
22 761.22 14/9, 17/11
23 795.821 27/17
24 830.422 21/13
25 865.023 23/14
26 899.624
27 934.225
28 968.826

Harmonics

Approximation of harmonics in 28ed7/4
Harmonic 2 3 4 5 6 7 8 9 10 11 12
Error Absolute (¢) +11.0 +1.1 -12.5 +16.4 +12.1 -12.5 -1.5 +2.2 -7.2 +0.8 -11.4
Relative (%) +31.9 +3.2 -36.2 +47.3 +35.1 -36.2 -4.3 +6.3 -20.8 +2.3 -33.1
Steps
(reduced)
35
(7)
55
(27)
69
(13)
81
(25)
90
(6)
97
(13)
104
(20)
110
(26)
115
(3)
120
(8)
124
(12)
Approximation of harmonics in 28ed7/4
Harmonic 13 14 15 16 17 18 19 20 21 22 23
Error Absolute (¢) -11.6 -1.5 -17.1 +9.5 +8.4 +13.2 -11.2 +3.8 -11.4 +11.8 +4.1
Relative (%) -33.6 -4.3 -49.5 +27.5 +24.2 +38.2 -32.3 +11.1 -33.1 +34.2 +11.8
Steps
(reduced)
128
(16)
132
(20)
135
(23)
139
(27)
142
(2)
145
(5)
147
(7)
150
(10)
152
(12)
155
(15)
157
(17)