87edt: Difference between revisions

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{{Infobox ET}}
'''[[Edt|Division of the third harmonic]] into 87 equal parts''' (87EDT) is related to [[55edo|55 edo]], but with the 3/1 rather than the 2/1 being just. The octave is about 2.3853 cents stretched and the step size is about 21.8616 cents. Unlike 55edo, it is only consistent up to the [[3-odd-limit|4-integer-limit]], with discrepancy for the 5th harmonic.
'''[[Edt|Division of the third harmonic]] into 87 equal parts''' (87EDT) is related to [[55edo|55 edo]], but with the 3/1 rather than the 2/1 being just. The octave is about 2.3853 cents stretched and the step size is about 21.8616 cents. Unlike 55edo, it is only consistent up to the [[3-odd-limit|4-integer-limit]], with discrepancy for the 5th harmonic.


Lookalikes: [[55edo]], [[142ed6]], [[154ed7]]
Lookalikes: [[55edo]], [[142ed6]], [[154ed7]]


[[Category:Edt]]
== Intervals ==
[[Category:Edonoi]]
{{Interval table}}
 
== Harmonics ==
{{Harmonics in equal
| steps = 87
| num = 3
| denom = 1
| intervals = integer
}}
{{Harmonics in equal
| steps = 87
| num = 3
| denom = 1
| start = 12
| collapsed = 1
| intervals = integer
}}

Latest revision as of 19:23, 1 August 2025

← 86edt 87edt 88edt →
Prime factorization 3 × 29
Step size 21.8616 ¢ 
Octave 55\87edt (1202.39 ¢)
Consistency limit 4
Distinct consistency limit 4

Division of the third harmonic into 87 equal parts (87EDT) is related to 55 edo, but with the 3/1 rather than the 2/1 being just. The octave is about 2.3853 cents stretched and the step size is about 21.8616 cents. Unlike 55edo, it is only consistent up to the 4-integer-limit, with discrepancy for the 5th harmonic.

Lookalikes: 55edo, 142ed6, 154ed7

Intervals

Steps Cents Hekts Approximate ratios
0 0 0 1/1
1 21.9 14.9
2 43.7 29.9 38/37, 39/38, 40/39, 41/40
3 65.6 44.8 27/26, 28/27
4 87.4 59.8 20/19, 41/39
5 109.3 74.7 33/31
6 131.2 89.7 14/13, 41/38
7 153 104.6 12/11
8 174.9 119.5 21/19, 31/28, 41/37
9 196.8 134.5 37/33
10 218.6 149.4 17/15
11 240.5 164.4 23/20, 31/27
12 262.3 179.3
13 284.2 194.3 20/17, 33/28
14 306.1 209.2 31/26, 37/31
15 327.9 224.1 23/19, 29/24
16 349.8 239.1 11/9, 38/31
17 371.6 254 26/21, 36/29
18 393.5 269
19 415.4 283.9 14/11, 33/26
20 437.2 298.9 9/7
21 459.1 313.8 30/23
22 481 328.7 29/22, 37/28
23 502.8 343.7
24 524.7 358.6 23/17
25 546.5 373.6 37/27
26 568.4 388.5
27 590.3 403.4 38/27
28 612.1 418.4 37/26
29 634 433.3 13/9
30 655.8 448.3 19/13
31 677.7 463.2 34/23, 40/27
32 699.6 478.2 3/2
33 721.4 493.1 41/27
34 743.3 508 20/13
35 765.2 523 14/9
36 787 537.9 41/26
37 808.9 552.9
38 830.7 567.8 21/13
39 852.6 582.8 18/11
40 874.5 597.7
41 896.3 612.6
42 918.2 627.6 17/10
43 940 642.5 31/18
44 961.9 657.5
45 983.8 672.4 30/17
46 1005.6 687.4 34/19
47 1027.5 702.3 29/16, 38/21
48 1049.4 717.2 11/6
49 1071.2 732.2 13/7
50 1093.1 747.1
51 1114.9 762.1 40/21
52 1136.8 777 27/14
53 1158.7 792 39/20, 41/21
54 1180.5 806.9
55 1202.4 821.8 2/1
56 1224.2 836.8
57 1246.1 851.7 37/18, 39/19
58 1268 866.7 27/13
59 1289.8 881.6 40/19
60 1311.7 896.6
61 1333.6 911.5 41/19
62 1355.4 926.4
63 1377.3 941.4 31/14
64 1399.1 956.3
65 1421 971.3
66 1442.9 986.2 23/10
67 1464.7 1001.1 7/3
68 1486.6 1016.1 26/11, 33/14
69 1508.4 1031
70 1530.3 1046 29/12
71 1552.2 1060.9 27/11
72 1574 1075.9
73 1595.9 1090.8
74 1617.8 1105.7 28/11
75 1639.6 1120.7
76 1661.5 1135.6
77 1683.3 1150.6 37/14
78 1705.2 1165.5
79 1727.1 1180.5 19/7
80 1748.9 1195.4 11/4
81 1770.8 1210.3 39/14
82 1792.6 1225.3 31/11
83 1814.5 1240.2
84 1836.4 1255.2 26/9
85 1858.2 1270.1 38/13, 41/14
86 1880.1 1285.1
87 1902 1300 3/1

Harmonics

Approximation of harmonics in 87edt
Harmonic 2 3 4 5 6 7 8 9 10 11 12
Error Absolute (¢) +2.39 +0.00 +4.77 -9.90 +2.39 -2.15 +7.16 +0.00 -7.51 +2.38 +4.77
Relative (%) +10.9 +0.0 +21.8 -45.3 +10.9 -9.8 +32.7 +0.0 -34.4 +10.9 +21.8
Steps
(reduced)
55
(55)
87
(0)
110
(23)
127
(40)
142
(55)
154
(67)
165
(78)
174
(0)
182
(8)
190
(16)
197
(23)
Approximation of harmonics in 87edt
Harmonic 13 14 15 16 17 18 19 20 21 22 23
Error Absolute (¢) -2.63 +0.24 -9.90 +9.54 -7.97 +2.39 -3.77 -5.13 -2.15 +4.76 -6.61
Relative (%) -12.0 +1.1 -45.3 +43.6 -36.4 +10.9 -17.3 -23.4 -9.8 +21.8 -30.2
Steps
(reduced)
203
(29)
209
(35)
214
(40)
220
(46)
224
(50)
229
(55)
233
(59)
237
(63)
241
(67)
245
(71)
248
(74)