Edϕ: Difference between revisions
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Various equal divisions of the octave have close approximations of acoustic phi. | Various equal divisions of the octave have close approximations of acoustic phi, or <span><math>φ</math></span>, ≈833.090296357¢. | ||
If the | If the <span><math>m^{th}</math></span> step of <span><math>n</math><span>ed2 is a close approximation of <span><math>φ</math></span>, the <span><math>n^{th}</math></span> step of <span><math>m</math><span>ed<span><math>φ</math></span> will be a close approximation of 2. | ||
Such m | For example, the 7th step of 10ed2 is 840¢, and the 10th step of 7ed<span><math>φ</math></span> is ≈1190.128995¢. | ||
As another example, the 9th step of 13ed2 is ≈830.7692308¢, and the 13th step of 9ed<span><math>φ</math></span> is ≈1203.35265¢. | |||
Such <span><math>m</math><span>ed<span><math>φ</math></span> are interesting as variants of their respective <span><math>n</math><span>ed<span><math>2</math><span>, introducing some combination tone powers. | |||
{| class="wikitable" | {| class="wikitable" | ||
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| | | | ||
| colspan="4" |'''10ed2''' | | colspan="4" |'''10ed2''' | ||
| colspan="4" |'''7edφ or 10ed(<math>2^{\frac{10log_2{φ}}{7}}</math>)''' | | colspan="4" |'''7edφ or 10ed(<math>2^{\frac{10log_2{φ}}{7}} ≈ 1.988629015</math>)''' | ||
|- | |- | ||
|'''scale step''' | |'''scale step''' | ||
Line 26: | Line 29: | ||
|120 | |120 | ||
|120 | |120 | ||
|<math>φ^{\frac{1}{7}}</math> or <math> | |<math>φ^{\frac{1}{7}}</math> or <math>≈1.988629015^{\frac{1}{10}}</math> | ||
|1.071162542 | |1.071162542 | ||
|119.0128995 | |119.0128995 | ||
Line 36: | Line 39: | ||
|240 | |240 | ||
|120 | |120 | ||
|<math>φ^{\frac{2}{7}}</math> or <math> | |<math>φ^{\frac{2}{7}}</math> or <math>≈1.988629015^{\frac{2}{10}}</math> | ||
|1.147389191 | |1.147389191 | ||
|238.025799 | |238.025799 | ||
Line 46: | Line 49: | ||
|360 | |360 | ||
|120 | |120 | ||
|<math>φ^{\frac{3}{7}}</math> or <math> | |<math>φ^{\frac{3}{7}}</math> or <math>≈1.988629015^{\frac{3}{10}}</math> | ||
|1.229040323 | |1.229040323 | ||
|357.0386984 | |357.0386984 | ||
Line 56: | Line 59: | ||
|480 | |480 | ||
|120 | |120 | ||
|<math>φ^{\frac{4}{7}}</math> or <math> | |<math>φ^{\frac{4}{7}}</math> or <math>≈1.988629015^{\frac{4}{10}}</math> | ||
|1.316501956 | |1.316501956 | ||
|476.0515979 | |476.0515979 | ||
Line 66: | Line 69: | ||
|600 | |600 | ||
|120 | |120 | ||
|<math>φ^{\frac{5}{7}}</math> or <math> | |<math>φ^{\frac{5}{7}}</math> or <math>≈1.988629015^{\frac{5}{10}}</math> | ||
|1.410187582 | |1.410187582 | ||
|595.0644974 | |595.0644974 | ||
Line 76: | Line 79: | ||
|720 | |720 | ||
|120 | |120 | ||
|<math>φ^{\frac{6}{7}}</math> or <math> | |<math>φ^{\frac{6}{7}}</math> or <math>≈1.988629015^{\frac{6}{10}}</math> | ||
|1.510540115 | |1.510540115 | ||
|714.0773969 | |714.0773969 | ||
Line 86: | Line 89: | ||
|840 | |840 | ||
|120 | |120 | ||
|<math>φ^{\frac{7}{7}}</math> or <math> | |<math>φ^{\frac{7}{7}}</math> or <math>≈1.988629015^{\frac{7}{10}}</math> | ||
|1.618033989 | |1.618033989 | ||
|833.0902964 | |833.0902964 | ||
Line 96: | Line 99: | ||
|960 | |960 | ||
|120 | |120 | ||
|<math>φ^{\frac{8}{7}}</math> or <math> | |<math>φ^{\frac{8}{7}}</math> or <math>≈1.988629015^{\frac{8}{10}}</math> | ||
|1.7331774 | |1.7331774 | ||
|952.1031958 | |952.1031958 | ||
Line 106: | Line 109: | ||
|1080 | |1080 | ||
|120 | |120 | ||
|<math>φ^{\frac{9}{7}}</math> or <math> | |<math>φ^{\frac{9}{7}}</math> or <math>≈1.988629015^{\frac{9}{10}}</math> | ||
|1.85651471 | |1.85651471 | ||
|1071.116095 | |1071.116095 | ||
Line 116: | Line 119: | ||
|1200 | |1200 | ||
|120 | |120 | ||
|<math>φ^{\frac{10}{7}}</math> or <math> | |<math>φ^{\frac{10}{7}}</math> or <math>≈1.988629015^{\frac{10}{10}}</math> | ||
|1.988629015 | |1.988629015 | ||
|1190.128995 | |1190.128995 | ||
|119.0128995 | |119.0128995 | ||
|} | |} |
Revision as of 00:03, 9 February 2020
Various equal divisions of the octave have close approximations of acoustic phi, or [math]\displaystyle{ φ }[/math], ≈833.090296357¢.
If the [math]\displaystyle{ m^{th} }[/math] step of [math]\displaystyle{ n }[/math]ed2 is a close approximation of [math]\displaystyle{ φ }[/math], the [math]\displaystyle{ n^{th} }[/math] step of [math]\displaystyle{ m }[/math]ed[math]\displaystyle{ φ }[/math] will be a close approximation of 2.
For example, the 7th step of 10ed2 is 840¢, and the 10th step of 7ed[math]\displaystyle{ φ }[/math] is ≈1190.128995¢. As another example, the 9th step of 13ed2 is ≈830.7692308¢, and the 13th step of 9ed[math]\displaystyle{ φ }[/math] is ≈1203.35265¢.
Such [math]\displaystyle{ m }[/math]ed[math]\displaystyle{ φ }[/math] are interesting as variants of their respective [math]\displaystyle{ n }[/math]ed[math]\displaystyle{ 2 }[/math], introducing some combination tone powers.
10ed2 | 7edφ or 10ed([math]\displaystyle{ 2^{\frac{10log_2{φ}}{7}} ≈ 1.988629015 }[/math]) | |||||||
scale step | frequency multiplier (definition) | 10ed2 frequency multiplier (decimal) | pitch (¢) | Δ (¢) | frequency multiplier (definition) | frequency multiplier (decimal) | pitch (¢) | Δ (¢) |
1 | [math]\displaystyle{ 2^{\frac{1}{10}} }[/math] | 1.071773463 | 120 | 120 | [math]\displaystyle{ φ^{\frac{1}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{1}{10}} }[/math] | 1.071162542 | 119.0128995 | 119.0128995 |
2 | [math]\displaystyle{ 2^{\frac{2}{10}} }[/math] | 1.148698355 | 240 | 120 | [math]\displaystyle{ φ^{\frac{2}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{2}{10}} }[/math] | 1.147389191 | 238.025799 | 119.0128995 |
3 | [math]\displaystyle{ 2^{\frac{3}{10}} }[/math] | 1.231144413 | 360 | 120 | [math]\displaystyle{ φ^{\frac{3}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{3}{10}} }[/math] | 1.229040323 | 357.0386984 | 119.0128995 |
4 | [math]\displaystyle{ 2^{\frac{4}{10}} }[/math] | 1.319507911 | 480 | 120 | [math]\displaystyle{ φ^{\frac{4}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{4}{10}} }[/math] | 1.316501956 | 476.0515979 | 119.0128995 |
5 | [math]\displaystyle{ 2^{\frac{5}{10}} }[/math] | 1.414213562 | 600 | 120 | [math]\displaystyle{ φ^{\frac{5}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{5}{10}} }[/math] | 1.410187582 | 595.0644974 | 119.0128995 |
6 | [math]\displaystyle{ 2^{\frac{6}{10}} }[/math] | 1.515716567 | 720 | 120 | [math]\displaystyle{ φ^{\frac{6}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{6}{10}} }[/math] | 1.510540115 | 714.0773969 | 119.0128995 |
7 | [math]\displaystyle{ 2^{\frac{7}{10}} }[/math] | 1.624504793 | 840 | 120 | [math]\displaystyle{ φ^{\frac{7}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{7}{10}} }[/math] | 1.618033989 | 833.0902964 | 119.0128995 |
8 | [math]\displaystyle{ 2^{\frac{8}{10}} }[/math] | 1.741101127 | 960 | 120 | [math]\displaystyle{ φ^{\frac{8}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{8}{10}} }[/math] | 1.7331774 | 952.1031958 | 119.0128995 |
9 | [math]\displaystyle{ 2^{\frac{9}{10}} }[/math] | 1.866065983 | 1080 | 120 | [math]\displaystyle{ φ^{\frac{9}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{9}{10}} }[/math] | 1.85651471 | 1071.116095 | 119.0128995 |
10 | [math]\displaystyle{ 2^{\frac{10}{10}} }[/math] | 2 | 1200 | 120 | [math]\displaystyle{ φ^{\frac{10}{7}} }[/math] or [math]\displaystyle{ ≈1.988629015^{\frac{10}{10}} }[/math] | 1.988629015 | 1190.128995 | 119.0128995 |