Class Spectral

Psychoacoustic analysis: harmonic series, combination tones, roughness, and sensory consonance.

Index

Constructors

Methods

beatFrequency combinationTones consonanceCurve overtoneSeries roughnessPlompLevelt sensoryConsonance

Constructors

constructor

new Spectral(): Spectral
Returns Spectral

Methods

`Static`beatFrequency

beatFrequency(f1: number, f2: number): number
Returns the beat frequency (interference) between two pitches.
Parameters
- f1: number
- f2: number
Returns number
- Defined in spectral.ts:49

`Static`combinationTones

combinationTones(
    f1: number,
    f2: number,
    order?: number,
): { difference: number[]; sum: number[] }
Computes sum and difference combination tones up to order. Only non-negative tones are returned.
Parameters
- f1: number
- f2: number
- order: number = 2
Returns { difference: number[]; sum: number[] }
- difference: number[]
  Difference tones |m·f1 − n·f2|, without zeros.
- sum: number[]
  Sum tones m·f1 + n·f2, for m and n from 1 to order.
- Defined in spectral.ts:24

`Static`consonanceCurve

consonanceCurve(intervalCents: number): number
Estimates sensory roughness based on the Plomp-Levelt critical bandwidth model. Returns a value 0 (smooth) to 1 (maximum roughness).

This is a simplified implementation - accurate only for simple sine-tone pairs. For complex spectra, use roughnessPlompLevelt.
Parameters
- intervalCents: number
Returns number
- Defined in spectral.ts:60

`Static`overtoneSeries

overtoneSeries(fundamental: number, count?: number): number[]
Returns the first count partials of the harmonic series starting at fundamental Hz.
Parameters
- fundamental: number
- count: number = 16
Returns number[]
- Defined in spectral.ts:16

`Static`roughnessPlompLevelt

roughnessPlompLevelt(frequencies: number[], amplitudes?: number[]): number
Estimates roughness for a set of frequencies using a pairwise Plomp-Levelt model. Lower values = more consonant.
Parameters
- frequencies: number[]
  Array of frequencies in Hz.
- Optionalamplitudes: number[]
  Optional amplitudes (default: all 1).
Returns number
- Defined in spectral.ts:79

`Static`sensoryConsonance

sensoryConsonance(chord: Chord, partials?: number, rolloff?: number): number
Estimates sensory consonance of a chord from the roughness between the harmonic partials of its notes (Sethares' model: partial k at k·f with amplitude rolloff^(k−1)). Only partials of different notes are paired. Returns 1 − roughness / the most roughness those partials could make, from 0 (rough) to 1 (smooth): a fifth scores above a tritone.
Parameters
- chord: Chord
  The chord to evaluate.
- partials: number = 6
  Harmonic partials per note (default 6; 1 = fundamentals only).
- rolloff: number = 0.88
  Amplitude ratio between consecutive partials (default 0.88).
Returns number
- Defined in spectral.ts:109