APS
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An APS, or arithmetic pitch sequence, is a kind of arithmetic and harmonotonic tuning.
Specification
Its full specification is (n-)APSp: (n pitches of an) arithmetic pitch sequence adding by irrational interval p. The n is optional. If not provided, the sequence is open-ended.
Formula
The pitch of the kth step of an APSp is quite simply k⋅p.
Relationship to other tunings
Vs. rank-1 temperaments & equal multiplications
An APSp is equivalent to a rank-1 temperament with generator p. It is also equivalent to an equal multiplication of p.
Vs. EPD
If specified, an APS will be equivalent to some EPD, or equal pitch division. Specifically, n-EPDx = n-APS(x/n), for example 12-EPD1200¢ = 12-APS(1200¢/12=100¢).
Vs. AS
The only difference between an APS and an AS (ambitonal sequence) is that the p for an APS is irrational.
Examples
| quantity | (0) | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| frequency (f) | (1) | 1.19 | 1.41 | 1.68 | 2 |
| pitch (log₂f) | (2⁰⸍⁴) | 2¹⸍⁴ | 2²⸍⁴ | 2³⸍⁴ | 2⁴⸍⁴ |
| length (1/f) | (1) | 0.84 | 0.71 | 0.59 | 0.5 |