21ed7/3

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← 20ed7/321ed7/322ed7/3 →
Prime factorization 3 × 7
Step size 69.851¢ 
Octave 17\21ed7/3 (1187.47¢)
Twelfth 27\21ed7/3 (1885.98¢) (→9\7ed7/3)
Consistency limit 5
Distinct consistency limit 4

21 equal divisions of 7/3 (abbreviated 21ed7/3) is a nonoctave tuning system that divides the interval of 7/3 into 21 equal parts of about 69.9 ¢ each. Each step represents a frequency ratio of (7/3)1/21, or the 21st root of 7/3.

Intervals

Steps Cents Approximate Ratios
0 0 1/1
1 69.851 21/20, 22/21
2 139.702 12/11, 25/23
3 209.553 9/8, 17/15
4 279.404 7/6, 20/17
5 349.255 11/9, 17/14
6 419.106 14/11, 19/15
7 488.957 4/3, 25/19
8 558.808 11/8
9 628.659 10/7
10 698.51 3/2
11 768.361 11/7, 14/9, 17/11
12 838.212 18/11
13 908.063 17/10
14 977.914 7/4, 23/13
15 1047.765 11/6, 20/11
16 1117.616 19/10, 21/11, 25/13
17 1187.467 2/1
18 1257.318
19 1327.169 15/7
20 1397.02 9/4, 20/9
21 1466.871 7/3

Harmonics

Approximation of harmonics in 21ed7/3
Harmonic 2 3 4 5 6 7 8 9 10 11 12
Error Absolute (¢) -12.5 -16.0 -25.1 +7.7 -28.5 -16.0 +32.3 -32.0 -4.8 -30.1 +28.8
Relative (%) -17.9 -22.9 -35.9 +11.1 -40.8 -22.9 +46.2 -45.7 -6.9 -43.1 +41.2
Steps
(reduced)
17
(17)
27
(6)
34
(13)
40
(19)
44
(2)
48
(6)
52
(10)
54
(12)
57
(15)
59
(17)
62
(20)
Approximation of harmonics in 21ed7/3
Harmonic 13 14 15 16 17 18 19 20 21 22 23
Error Absolute (¢) +29.9 -28.5 -8.3 +19.7 -15.4 +25.4 +1.6 -17.3 -32.0 +27.2 +20.1
Relative (%) +42.9 -40.8 -11.8 +28.2 -22.0 +36.3 +2.3 -24.8 -45.7 +39.0 +28.8
Steps
(reduced)
64
(1)
65
(2)
67
(4)
69
(6)
70
(7)
72
(9)
73
(10)
74
(11)
75
(12)
77
(14)
78
(15)