ALS: Difference between revisions

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{| class="wikitable"
{| class="wikitable"
|+example: (1/⁴√2)-shifted undertone series segment = 9-ALS(1/⁴√2)
|+example: (1/⁴√2)-shifted undertone series segment = 8-ALS(1/⁴√2)
|-
|-
! quantity
! quantity
! (0)
! 1
! 1
! 2
! 2
Line 17: Line 18:
! 7
! 7
! 8
! 8
! 9
|-
|-
! frequency
! frequency (f)
|1.00
|1.00
|1.12
|1.12
Line 30: Line 30:
|7.73
|7.73
|-
|-
! pitch
! pitch (log₂f)
|0.00
|0.00
|0.17
|0.17
Line 41: Line 41:
|2.95
|2.95
|-
|-
! length
! length (1/f)
|1.00
|1.00
|0.89
|0.89

Revision as of 22:02, 22 March 2021

An ALS, or arithmetic length sequence, is a kind of arithmetic and monotonic tuning.

Is full specification is (n-)ALSp: (n pitches of an) arithmetic length sequence adding by p. It is equivalent to an undertone series shifted ± frequency.

A US, or utonal sequence, is a specific (rational) type of ALS. By varying the undertone series step size to some rational number (other than 1) you can produce a US, and by varying it to an irrational number you can produce an ALS. In other words, by shifting the undertone series by a constant amount of string length, the step sizes remain equal in terms of length, but their relationship in pitch changes.

example: (1/⁴√2)-shifted undertone series segment = 8-ALS(1/⁴√2)
quantity (0) 1 2 3 4 5 6 7 8
frequency (f) 1.00 1.12 1.28 1.48 1.77 2.19 2.88 4.20 7.73
pitch (log₂f) 0.00 0.17 0.35 0.57 0.82 1.13 1.53 2.07 2.95
length (1/f) 1.00 0.89 0.78 0.67 0.56 0.46 0.35 0.24 0.13