scherz

opinionated generative music

Intro

scherz can generate chord progressions using color, dissonance, and gravity

• increasing color raises the chances of chords venturing further in the circle of fifths
• increasing dissonance results in more "unnatural" sounding chords
• increasing gravity prioritizes half step resolutions and tighter voice leading

Build instructions (requires npm)

npm init
npm install scherz

in the repl, we can generate a progression with the required parameters. for example:

const { generateProgression } = require('scherz')
const forces = [
    { color: 0, dissonance: 0.2, gravity: 0.5 },
    { color: 0.4, dissonance: 0.4, gravity: 0.25 },
    { color: 0, dissonance: 0.8, gravity: 0 },
    { color: 0.2, dissonance: 0.2, gravity: 0.25 },
]
const scales = ['lydian']
const options = { type: "M7", tonic: "D", dissonance: 0.15 }
generateProgression(scales, forces, options)
=>  [ { scale: 'lydian',
        inversion: 0,
        name: 'AM',
        tonic: 'D',
        pitches: [ 'A', 'E', 'C#', 'A' ],
        dissonance: 10,
        notes: [ 45, 52, 61, 69 ] },
      { scale: 'lydian',
        inversion: 0,
        name: 'F♯m/B',
        tonic: 'D',
        pitches: [ 'B', 'F#', 'C#', 'A' ],
        dissonance: 12,
        notes: [ 47, 54, 61, 69 ] },
      { scale: 'lydian',
        inversion: 3,
        name: 'G♯m7add4',
        tonic: 'E',
        pitches: [ 'F#', 'B', 'C#', 'G#', 'D#' ],
        dissonance: 15,
        notes: [ 54, 59, 61, 68, 75 ] },
      { scale: 'lydian',
        inversion: 1,
        name: 'F♯7sus4/D♯',
        tonic: 'E',
        pitches: [ 'D#', 'B', 'E', 'C#', 'F#' ],
        dissonance: 24,
        notes: [ 51, 59, 64, 73, 78 ] },
      { scale: 'lydian',
        inversion: 1,
        name: 'G♯m7add9',
        tonic: 'B',
        pitches: [ 'B', 'G#', 'D#', 'F#', 'A#' ],
        dissonance: 11,
        notes: [ 47, 56, 63, 66, 70 ] } ]

generateProgression takes in three parameters:

• a list of objects (referred to as forces),
  • color consonance and gravity are required
  • each value corresponding to these keys must be between 0 and 1
• a list of scales to choose chords from, ["lydian", "diminished"] for example
  • util.scales contains a list of all possible scales
• an optional "options" object, which takes contains three keys:
  • tonic the root of the initial chord (defaults to "C")
  • seed an integer that determines which chord is chosen in case of a tie
  • dissonance a number between 0 and 1 that affects the dissonance of the first chord

we can generate chords one by one using generateChords which also takes in three parameters and outputs a list of chords matching the corresponding color, consonance, and gravity

• a list of scales to choose chords from
• the previous chord
• an object with the keys color consonance and gravity

const { initialChords, generateChords } = require('scherz')
const scales = ['melodic-minor', 'augmented']

// initialChord optionally takes in a third parameter that corresponds to dissonance
const initialChord = initialChords(scales, "Db", 0.25)[0]

const force = { color: 0.25, dissonance: 0.5, gravity: 0.5 }
generateChords(scales, initialChord, force)
=>  [ { scale: 'melodic-minor',
        inversion: 0,
        name: 'D♭7sus2add13',
        tonic: 'Ab',
        pitches: [ 'Db', 'Cb', 'Ab', 'Bb', 'Eb' ],
        dissonance: 18,
        notes: [ 49, 59, 68, 70, 75 ] } ]

forces can have three optional keys: arc temper and incline, which must have either "asc" or "desc" as their corresponding values

• arc: "asc" ensures that generated chords modulate only to brighter keys
• temper: "asc" attempts to generate "happy" sounding chords
• incline: "asc" generates chords that are spatially higher than the previous chord