18edf: Difference between revisions
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18edf is related to the [[regular temperament]] which [[tempering out|tempers out]] 2401/2400 and 8589934592/8544921875 in the [[7-limit]]; with 5632/5625, 46656/46585, and 166698/166375 in the [[11-limit]], which is supported by [[31edo]], [[369edo]], [[400edo]], [[431edo]], and [[462edo]]. | 18edf is related to the [[regular temperament]] which [[tempering out|tempers out]] 2401/2400 and 8589934592/8544921875 in the [[7-limit]]; with 5632/5625, 46656/46585, and 166698/166375 in the [[11-limit]], which is supported by [[31edo]], [[369edo]], [[400edo]], [[431edo]], and [[462edo]]. | ||
Lookalikes: [[31edo]], [[49edt]], [[72ed5]], [[80ed6]] | Lookalikes: [[31edo]], [[39cET]], [[49edt]], [[72ed5]], [[80ed6]] | ||
=== Harmonics === | === Harmonics === | ||
Line 13: | Line 13: | ||
== Intervals == | == Intervals == | ||
{| class="wikitable mw-collapsible" | {| class="wikitable mw-collapsible" | ||
|+ Intervals of 18edf | |+ style="font-size: 105%;" | Intervals of 18edf | ||
|- | |- | ||
! | ! Degree | ||
! | ! Cents value | ||
! | ! Corresponding<br />JI intervals | ||
! | ! Comments | ||
|- | |- | ||
! colspan="2" | 0 | ! colspan="2" | 0 | ||
| '''exact [[1/1]]''' | |||
| | |||
|- | |- | ||
| 1 | |||
| 38.9975 | |||
| 45/44 | |||
| | |||
|- | |- | ||
| 2 | |||
| 77.995 | |||
| | |||
| | |||
|- | |- | ||
| 3 | |||
| 116.9925 | |||
| 16/15 | |||
| | |||
|- | |- | ||
| 4 | |||
| 155.99 | |||
| 128/117 | |||
| | |||
|- | |- | ||
| 5 | |||
| 194.9875 | |||
| 28/25 | |||
| | |||
|- | |- | ||
| 6 | |||
| 233.985 | |||
| 8/7 | |||
| | |||
|- | |- | ||
| 7 | |||
| 272.9825 | |||
| 7/6 | |||
| | |||
|- | |- | ||
| 8 | |||
| 311.98 | |||
| 6/5 | |||
| | |||
|- | |- | ||
| 9 | |||
| 350.9775 | |||
| 60/49, 49/40 | |||
| | |||
|- | |- | ||
| 10 | |||
| 389.975 | |||
| 5/4 | |||
| | |||
|- | |- | ||
| 11 | |||
| 428.9725 | |||
| 9/7 | |||
| | |||
|- | |- | ||
| 12 | |||
| 467.97 | |||
| | |||
| | |||
|- | |- | ||
| 13 | |||
| 506.9675 | |||
| 75/56 | |||
| | |||
|- | |- | ||
| 14 | |||
| 545.965 | |||
| | |||
| | |||
|- | |- | ||
| 15 | |||
| 584.9625 | |||
| | |||
| | |||
|- | |- | ||
| 16 | |||
| 623.96 | |||
| | |||
| | |||
|- | |- | ||
| 17 | |||
| 662.9575 | |||
| [[22/15]] | |||
| | |||
|- | |- | ||
| 18 | |||
| 701.955 | |||
| '''exact [[3/2]]''' | |||
| just perfect fifth | |||
|- | |- | ||
|19 | | 19 | ||
|740.9525 | | 740.9525 | ||
|135/88 | | 135/88 | ||
| | | | ||
|- | |- | ||
|20 | | 20 | ||
|779.95 | | 779.95 | ||
| | | | ||
| | | | ||
|- | |- | ||
|21 | | 21 | ||
|818.9475 | | 818.9475 | ||
|8/5 | | 8/5 | ||
| | | | ||
|- | |- | ||
|22 | | 22 | ||
|857.945 | | 857.945 | ||
|64/39 | | 64/39 | ||
| | | | ||
|- | |- | ||
|23 | | 23 | ||
|896.9425 | | 896.9425 | ||
|42/25 | | 42/25 | ||
| | | | ||
|- | |- | ||
|24 | | 24 | ||
|935.94 | | 935.94 | ||
|12/7 | | 12/7 | ||
| | | | ||
|- | |- | ||
|25 | | 25 | ||
|974.9375 | | 974.9375 | ||
|7/4 | | 7/4 | ||
| | | | ||
|- | |- | ||
|26 | | 26 | ||
|1013.935 | | 1013.935 | ||
|9/5 | | 9/5 | ||
| | | | ||
|- | |- | ||
|27 | | 27 | ||
|1052.9325 | | 1052.9325 | ||
|90/49, 147/80 | | 90/49, 147/80 | ||
| | | | ||
|- | |- | ||
|28 | | 28 | ||
|1091.93 | | 1091.93 | ||
|15/8 | | 15/8 | ||
| | | | ||
|- | |- | ||
|29 | | 29 | ||
|1130.9275 | | 1130.9275 | ||
|27/14 | | 27/14 | ||
| | | | ||
|- | |- | ||
|30 | | 30 | ||
|1169.925 | | 1169.925 | ||
| | | | ||
| | | | ||
|- | |- | ||
|31 | | 31 | ||
|1208.9225 | | 1208.9225 | ||
|225/112 | | 225/112 | ||
| | | | ||
|- | |- | ||
|32 | | 32 | ||
|1247.92 | | 1247.92 | ||
| | | | ||
| | | | ||
|- | |- | ||
|33 | | 33 | ||
|1286.9175 | | 1286.9175 | ||
| | | | ||
| | | | ||
|- | |- | ||
|34 | | 34 | ||
|1325.915 | | 1325.915 | ||
| | | | ||
| | | | ||
|- | |- | ||
|35 | | 35 | ||
|1364.9125 | | 1364.9125 | ||
| | | | ||
| | | | ||
|- | |- | ||
|36 | | 36 | ||
|1403.91 | | 1403.91 | ||
|'''exact''' 9/4 | | '''exact''' 9/4 | ||
| | | | ||
|} | |} | ||
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The rank-two regular temperament supported by 31edo and 369edo has three equal divisions of the interval which equals an octave minus the step interval of 18EDF as a generator. | The rank-two regular temperament supported by 31edo and 369edo has three equal divisions of the interval which equals an octave minus the step interval of 18EDF as a generator. | ||
=== 7-limit 31&369 === | === 7-limit 31 & 369 === | ||
Commas: 2401/2400, 8589934592/8544921875 | Commas: 2401/2400, 8589934592/8544921875 | ||
POTE generator: ~5/4 = 386.997 | POTE generator: ~5/4 = 386.997 | ||
Mapping: [ | Mapping: [{{map| 1 19 2 7 }}, {{map| 0 -54 1 -13 }}] | ||
EDOs: {{EDOs|31, 369, 400, 431, 462}} | EDOs: {{EDOs|31, 369, 400, 431, 462}} | ||
===11-limit 31&369=== | === 11-limit 31 & 369 === | ||
Commas: 2401/2400, 5632/5625, 46656/46585 | Commas: 2401/2400, 5632/5625, 46656/46585 | ||
POTE generator: ~5/4 = 386.999 | POTE generator: ~5/4 = 386.999 | ||
Mapping: [ | Mapping: [{{map| 1 19 2 7 37 }}, {{map| 0 -54 1 -13 -104 }}] | ||
EDOs: 31, 369, 400, 431, 462 | EDOs: 31, 369, 400, 431, 462 | ||
===13-limit 31&369=== | === 13-limit 31 & 369 === | ||
Commas: 1001/1000, 1716/1715, 4096/4095, 46656/46585 | Commas: 1001/1000, 1716/1715, 4096/4095, 46656/46585 | ||
POTE generator: ~5/4 = 387.003 | POTE generator: ~5/4 = 387.003 | ||
Mapping: [ | Mapping: [{{map| 1 19 2 7 37 -35 }}, {{map| 0 -54 1 -13 -104 120 }}] | ||
EDOs: 31, 369, 400, 431, 462 | EDOs: 31, 369, 400, 431, 462 | ||
{{Todo|cleanup|expand|inline=1|comment=say what the temperaments are like and why one would want to use them, and for what}} | {{Todo|cleanup|expand|inline=1|comment=say what the temperaments are like and why one would want to use them, and for what}} |
Revision as of 16:47, 21 January 2025
← 17edf | 18edf | 19edf → |
18 equal divisions of the perfect fifth (abbreviated 18edf or 18ed3/2) is a nonoctave tuning system that divides the interval of 3/2 into 18 equal parts of about 39 ¢ each. Each step represents a frequency ratio of (3/2)1/18, or the 18th root of 3/2.
Theory
18edf is related to the regular temperament which tempers out 2401/2400 and 8589934592/8544921875 in the 7-limit; with 5632/5625, 46656/46585, and 166698/166375 in the 11-limit, which is supported by 31edo, 369edo, 400edo, 431edo, and 462edo.
Lookalikes: 31edo, 39cET, 49edt, 72ed5, 80ed6
Harmonics
Harmonic | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Error | Absolute (¢) | +8.9 | +8.9 | +17.8 | -17.5 | +17.8 | -15.0 | -12.2 | +17.8 | -8.6 | -17.6 | -12.2 |
Relative (%) | +22.9 | +22.9 | +45.8 | -44.9 | +45.8 | -38.6 | -31.4 | +45.8 | -22.0 | -45.1 | -31.4 | |
Steps (reduced) |
31 (13) |
49 (13) |
62 (8) |
71 (17) |
80 (8) |
86 (14) |
92 (2) |
98 (8) |
102 (12) |
106 (16) |
110 (2) |
Harmonic | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Error | Absolute (¢) | +5.2 | -6.1 | -8.6 | -3.3 | +8.7 | -12.2 | +11.2 | +0.4 | -6.1 | -8.7 | -7.6 |
Relative (%) | +13.3 | -15.7 | -22.0 | -8.5 | +22.4 | -31.4 | +28.6 | +0.9 | -15.7 | -22.2 | -19.5 | |
Steps (reduced) |
114 (6) |
117 (9) |
120 (12) |
123 (15) |
126 (0) |
128 (2) |
131 (5) |
133 (7) |
135 (9) |
137 (11) |
139 (13) |
Intervals
Degree | Cents value | Corresponding JI intervals |
Comments |
---|---|---|---|
0 | exact 1/1 | ||
1 | 38.9975 | 45/44 | |
2 | 77.995 | ||
3 | 116.9925 | 16/15 | |
4 | 155.99 | 128/117 | |
5 | 194.9875 | 28/25 | |
6 | 233.985 | 8/7 | |
7 | 272.9825 | 7/6 | |
8 | 311.98 | 6/5 | |
9 | 350.9775 | 60/49, 49/40 | |
10 | 389.975 | 5/4 | |
11 | 428.9725 | 9/7 | |
12 | 467.97 | ||
13 | 506.9675 | 75/56 | |
14 | 545.965 | ||
15 | 584.9625 | ||
16 | 623.96 | ||
17 | 662.9575 | 22/15 | |
18 | 701.955 | exact 3/2 | just perfect fifth |
19 | 740.9525 | 135/88 | |
20 | 779.95 | ||
21 | 818.9475 | 8/5 | |
22 | 857.945 | 64/39 | |
23 | 896.9425 | 42/25 | |
24 | 935.94 | 12/7 | |
25 | 974.9375 | 7/4 | |
26 | 1013.935 | 9/5 | |
27 | 1052.9325 | 90/49, 147/80 | |
28 | 1091.93 | 15/8 | |
29 | 1130.9275 | 27/14 | |
30 | 1169.925 | ||
31 | 1208.9225 | 225/112 | |
32 | 1247.92 | ||
33 | 1286.9175 | ||
34 | 1325.915 | ||
35 | 1364.9125 | ||
36 | 1403.91 | exact 9/4 |
Related regular temperaments
The rank-two regular temperament supported by 31edo and 369edo has three equal divisions of the interval which equals an octave minus the step interval of 18EDF as a generator.
7-limit 31 & 369
Commas: 2401/2400, 8589934592/8544921875
POTE generator: ~5/4 = 386.997
Mapping: [⟨1 19 2 7], ⟨0 -54 1 -13]]
11-limit 31 & 369
Commas: 2401/2400, 5632/5625, 46656/46585
POTE generator: ~5/4 = 386.999
Mapping: [⟨1 19 2 7 37], ⟨0 -54 1 -13 -104]]
EDOs: 31, 369, 400, 431, 462
13-limit 31 & 369
Commas: 1001/1000, 1716/1715, 4096/4095, 46656/46585
POTE generator: ~5/4 = 387.003
Mapping: [⟨1 19 2 7 37 -35], ⟨0 -54 1 -13 -104 120]]
EDOs: 31, 369, 400, 431, 462