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Revision as of 00:04, 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 |