18ed7/4

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← 17ed7/418ed7/419ed7/4 →
Prime factorization 2 × 32
Step size 53.8237¢ 
Octave 22\18ed7/4 (1184.12¢) (→11\9ed7/4)
Twelfth 35\18ed7/4 (1883.83¢)
(semiconvergent)
Consistency limit 3
Distinct consistency limit 3

18 equal divisions of 7/4 (abbreviated 18ed7/4) is a nonoctave tuning system that divides the interval of 7/4 into 18 equal parts of about 53.8 ¢ each. Each step represents a frequency ratio of (7/4)1/18, or the 18th root of 7/4.

Intervals

Steps Cents Approximate Ratios
0 0 1/1
1 53.824
2 107.647 15/14
3 161.471 11/10, 21/19, 23/21
4 215.295 9/8, 17/15
5 269.118 20/17
6 322.942 17/14, 23/19
7 376.766 21/17
8 430.589 14/11, 22/17
9 484.413 4/3
10 538.237 15/11, 19/14, 23/17
11 592.06 7/5
12 645.884 19/13, 22/15
13 699.708 3/2
14 753.531 17/11, 23/15
15 807.355
16 861.179 23/14
17 915.002 17/10
18 968.826

Harmonics

Approximation of harmonics in 18ed7/4
Harmonic 2 3 4 5 6 7 8 9 10 11 12
Error Absolute (¢) -15.9 -18.1 +22.1 +12.5 +19.8 +22.1 +6.2 +17.6 -3.4 -6.9 +3.9
Relative (%) -29.5 -33.7 +41.0 +23.3 +36.8 +41.0 +11.5 +32.6 -6.2 -12.8 +7.3
Steps
(reduced)
22
(4)
35
(17)
45
(9)
52
(16)
58
(4)
63
(9)
67
(13)
71
(17)
74
(2)
77
(5)
80
(8)
Approximation of harmonics in 18ed7/4
Harmonic 13 14 15 16 17 18 19 20 21 22 23
Error Absolute (¢) +26.8 +6.2 -5.6 -9.7 -7.0 +1.7 +15.7 -19.2 +3.9 -22.8 +7.9
Relative (%) +49.9 +11.5 -10.4 -18.0 -13.0 +3.1 +29.2 -35.8 +7.3 -42.3 +14.7
Steps
(reduced)
83
(11)
85
(13)
87
(15)
89
(17)
91
(1)
93
(3)
95
(5)
96
(6)
98
(8)
99
(9)
101
(11)