Metallic harmonic series

Revision as of 05:35, 5 February 2020 by Cmloegcmluin (talk | contribs)

The sequence of metallic means can be used as a variation on the harmonic series.

step metallic harmonic series harmonic series difference (¢)
frequency multiplier (definition) frequency multiplier (decimal) pitch (¢) frequency multiplier (decimal) pitch (¢)
0 <math>\frac{0+sqrt{0^2 + 4}}{2}</math> 1 0 - - -
1 1.618033989 833.090296 1.000000 0 833.0902964
2 2.414213562 1525.863964 2.000000 1200 325.8639638
3 3.302775638 2068.414762 3.000000 1901.955001 166.4597615
4 4.236067977 2499.270889 4.000000 2400 99.27088907
5 5.192582404 2851.742647 5.000000 2786.313714 65.42893342
6 6.16227766 3148.156427 6.000000 3101.955001 46.20142576
7 7.140054945 3403.122211 7.000000 3368.825906 34.296305
8 8.123105626 3626.437685 8.000000 3600 26.43768483
9 9.109772229 3824.897979 9.000000 3803.910002 20.98797765
10 10.09901951 4003.371993 10.000000 3986.313714 17.05827891
11 11.09016994 4165.451482 11.000000 4151.317942 14.13353942
12 12.08276253 4313.854124 12.000000 4301.955001 11.89912281
13 13.07647322 4450.681905 13.000000 4440.527662 10.15424279
14 14.07106781 4577.591891 14.000000 4568.825906 8.76598492
15 15.06637298 4695.912293 15.000000 4688.268715 7.643578517
16 16.06225775 4806.723349 16.000000 4800 6.7233486789

The zeroth metallic mean, [math]\displaystyle{ μ_0 }[/math], is equal to 1, and for each subsequent metallic mean:

[math]\displaystyle{ n \lt μ_n \lt n + 1 }[/math]

Each successive metallic mean is closer to the lower of its two bounding integers than the previous metallic mean was, so eventually you'll converge onto the traditional harmonic series. But at the beginning this sequence is quite a bit different; the first metallic mean, the golden mean, is ≈1.618, is actually closer to 2 than it is to 1. And the second metallic mean, the silver mean, is ≈2.414, also still a ways off from 2. The sequence continues ≈3.303, ≈4.236, ≈5.193, ≈6.162, ≈7.140, ≈8.123, ≈9.110, ≈10.099, ≈11.090, ≈12.083, ≈13.076, ≈14.071, ≈15.066, etc. So in other words it starts out sounding quite like its own thing, but eventually starts to sound like the traditional harmonic series.

Combination tones from this scale.