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A couple such scales can be found in the [[Scala Scale Archive|Huygens-Fokker Foundation's Scala scale archive]]. They were described by Walter O'Connell in his 1993 paper [http://anaphoria.com/oconnell.pdf The Tonality of the Golden Section].
A couple such scales can be found in the [[Scala Scale Archive|Huygens-Fokker Foundation's Scala scale archive]]. They were described by Walter O'Connell in his 1993 paper [http://anaphoria.com/oconnell.pdf The Tonality of the Golden Section]. The 18th root of phi scale doubles the resolution of the 9th root scale featured above, and notably introduces a good 3/2 and a good 7/4.


  cet33.scl                      25  25th root of phi, Walter O´Connell (1993)
  cet33.scl                      25  25th root of phi, Walter O´Connell (1993)
  cet46.scl                      18  18th root of phi, Walter O´Connell (1993)
  cet46.scl                      18  18th root of phi, Walter O´Connell (1993)

Revision as of 19:38, 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.

scale step 10ed2 7edφ or 10ed([math]\displaystyle{ 2^{\frac{10log_2{φ}}{7}} ≈ 1.988629015 }[/math])
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
scale step 13ed2 9edφ or 13ed([math]\displaystyle{ 2^{\frac{13log_2{φ}}{9}} ≈ 2.003876886 }[/math])
frequency multiplier (definition) 10ed2 frequency multiplier (decimal) pitch (¢) Δ (¢) frequency multiplier (definition) frequency multiplier (decimal) pitch (¢) Δ (¢)
1 [math]\displaystyle{ 2^{\frac{1}{13}} }[/math] 1.054766076 92.30769231 92.30769231 [math]\displaystyle{ φ^{\frac{1}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{1}{13}} }[/math] 1.054923213 92.56558848 92.56558848
2 [math]\displaystyle{ 2^{\frac{2}{13}} }[/math] 1.112531476 184.6153846 92.30769231 [math]\displaystyle{ φ^{\frac{2}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{2}{13}} }[/math] 1.112862986 185.131177 92.56558848
3 [math]\displaystyle{ 2^{\frac{3}{13}} }[/math] 1.17346046 276.9230769 92.30769231 [math]\displaystyle{ φ^{\frac{3}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{3}{13}} }[/math] 1.173984997 277.6967655 92.56558848
4 [math]\displaystyle{ 2^{\frac{4}{13}} }[/math] 1.237726285 369.2307692 92.30769231 [math]\displaystyle{ φ^{\frac{4}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{4}{13}} }[/math] 1.238464025 370.2623539 92.56558848
5 [math]\displaystyle{ 2^{\frac{5}{13}} }[/math] 1.305511698 461.5384615 92.30769231 [math]\displaystyle{ φ^{\frac{5}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{5}{13}} }[/math] 1.306484449 462.8279424 92.56558848
6 [math]\displaystyle{ 2^{\frac{6}{13}} }[/math] 1.377009451 553.8461538 92.30769231 [math]\displaystyle{ φ^{\frac{6}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{6}{13}} }[/math] 1.378240772 555.3935309 92.56558848
7 [math]\displaystyle{ 2^{\frac{7}{13}} }[/math] 1.452422856 646.1538462 92.30769231 [math]\displaystyle{ φ^{\frac{7}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{7}{13}} }[/math] 1.453938184 647.9591194 92.56558848
8 [math]\displaystyle{ 2^{\frac{8}{13}} }[/math] 1.531966357 738.4615385 92.30769231 [math]\displaystyle{ φ^{\frac{8}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{8}{13}} }[/math] 1.533793141 740.5247079 92.56558848
9 [math]\displaystyle{ 2^{\frac{9}{13}} }[/math] 1.615866144 830.7692308 92.30769231 [math]\displaystyle{ φ^{\frac{9}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{9}{13}} }[/math] 1.618033989 833.0902964 92.56558848
10 [math]\displaystyle{ 2^{\frac{10}{13}} }[/math] 1.704360793 923.0769231 92.30769231 [math]\displaystyle{ φ^{\frac{10}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{10}{13}} }[/math] 1.706901614 925.6558848 92.56558848
11 [math]\displaystyle{ 2^{\frac{11}{13}} }[/math] 1.797701946 1015.384615 92.30769231 [math]\displaystyle{ φ^{\frac{11}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{11}{13}} }[/math] 1.800650136 1018.221473 92.56558848
12 [math]\displaystyle{ 2^{\frac{12}{13}} }[/math] 1.896155029 1107.692308 92.30769231 [math]\displaystyle{ φ^{\frac{12}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{12}{13}} }[/math] 1.899547627 1110.787062 92.56558848
13 [math]\displaystyle{ 2^{\frac{13}{13}} }[/math] 2 1200 92.30769231 [math]\displaystyle{ φ^{\frac{13}{9}} }[/math] or [math]\displaystyle{ ≈2.003876886^{\frac{13}{13}} }[/math] 2.003876886 1203.35265 92.56558848

A couple such scales can be found in the Huygens-Fokker Foundation's Scala scale archive. They were described by Walter O'Connell in his 1993 paper The Tonality of the Golden Section. The 18th root of phi scale doubles the resolution of the 9th root scale featured above, and notably introduces a good 3/2 and a good 7/4.

cet33.scl                      25  25th root of phi, Walter O´Connell (1993)
cet46.scl                      18  18th root of phi, Walter O´Connell (1993)