45zpi

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45 zeta peak index (abbreviated 45zpi), is the equal-step tuning system obtained from the 45th peak of the Riemann zeta function.

Tuning Strength Closest EDO Integer limit
ZPI Steps per octave Step size (cents) Height Integral Gap EDO Octave (cents) Consistent Distinct
45zpi 14.5944346577250 82.2231232756126 2.097730 0.344839 10.594800 15edo 1233.34684913419 2 2

Theory

45zpi is characterized by a very broad octave error, yet it maintains a quite decent zeta strength. This combination makes it an ideal candidate for no-octave tuning applications.

No other zeta peak indexes exhibit both a larger octave error and greater zeta height than 45zpi.

45zpi supports a complex chord structure with ratios of 1:3:4:5:7:9:13:15:18:19:20:21:22:23:24:25, which further exemplifies its capabilities.

The closest zeta peak indexes to 45zpi that exceed its strength are 42zpi and 47zpi, though 43zpi is nearly as strong as 45zpi.

Harmonic series

Approximation of harmonics in 45zpi
Harmonic 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Error absolute (¢) +33.3 -10.8 -15.5 +9.3 +22.5 +2.3 +17.8 -21.6 -39.6 -40.2 -26.4 -0.5 +35.7 -1.6 -31.1
relative (%) +41 -13 -19 +11 +27 +3 +22 -26 -48 -49 -32 -1 +43 -2 -38
Steps 15 23 29 34 38 41 44 46 48 50 52 54 56 57 58
Approximation of harmonics in 45zpi
Harmonic 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
Error absolute (¢) +28.4 +11.7 +0.3 -6.3 -8.5 -6.8 -1.5 +7.0 +18.5 +32.9 -32.5 -13.2 +8.3 +31.8 -25.0 +2.3
relative (%) +35 +14 +0 -8 -10 -8 -2 +9 +23 +40 -39 -16 +10 +39 -30 +3
Steps 60 61 62 63 64 65 66 67 68 69 69 70 71 72 72 73
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