Random Voice Leading Motion Exercise Generator

Description

Generate bounded two-voice MIDI transitions with sharp-spelled interval prompts and delegated motion and consonance classifications.

A musical fixture expresses pitch or timing through explicit numeric conventions such as MIDI numbers, semitone intervals, beats, and durations. A reproducible symbolic sequence is separate from a performed sound or a judgment of musical quality.

Generate bounded two-voice MIDI transitions with sharp-spelled interval prompts and delegated motion and consonance classifications.

When to use this tool

Use this generator to create reproducible voice leading motion exercise cases from the supplied model or bank. Inspect the returned evidence before using cases in a test or exercise.

How to use the tool and how it works

Supply count, midiRange, maximumLeapSemitones, lowerVoiceIsBass in the field shapes below. Set seed when you need an explicit replay.
Run the tool and correct any input error. For generated controls, distinguish a successful fixture containing an invalid case from failure to generate the fixture.
Read exercises. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.

Draw two starting MIDI pitches, then draw each next pitch within the supplied range and maximum semitone leap. Spell pitches with the supported sharp-note convention, delegate two-voice motion classification and classify before/after intervals using lowerVoiceIsBass.^[1]

Delegated operations used for this result: voice leading motion classifier; counterpoint consonance classifier. Their calculation or parsing conventions apply to the corresponding result fields.^{[2, 3]}

Input field	Meaning and units	Accepted input
count	Requested count; the mechanics explain whether one draw expands into several returned records.	Required. Safe integer; minimum 1; maximum 64.
midiRange	Midi Range	Required. Object; no unknown keys.
midiRange.minimum	Minimum	Required. Safe integer; minimum 0; maximum 127.
midiRange.maximum	Maximum	Required. Safe integer; minimum 0; maximum 127.
maximumLeapSemitones	Maximum Leap Semitones	Required. Safe integer; minimum 0; maximum 24.
lowerVoiceIsBass	Lower Voice Is Bass	Required. Boolean.
seed	Optional numeric seed; takes precedence over context randomness. Without either, use the fixed tool.io default seed.	Optional. Safe integer.

Output field	Interpretation	Returned shape
exercises	Exercises	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 64.
exercises[].firstVoiceMidiPair	First Voice Midi Pair	Required. Array of Safe integer; minimum 0; maximum 127.; minimum items 2; maximum items 2.
exercises[].secondVoiceMidiPair	Second Voice Midi Pair	Required. Array of Safe integer; minimum 0; maximum 127.; minimum items 2; maximum items 2.
exercises[].twoVoiceMotionClass	Two Voice Motion Class	Required. Text.
exercises[].firstVoiceSignedMotion	First Voice Signed Motion	Required. Safe integer.
exercises[].secondVoiceSignedMotion	Second Voice Signed Motion	Required. Safe integer.
exercises[].voiceCrossingObserved	Voice Crossing Observed	Required. Boolean.
exercises[].before	Before	Required. Object; no unknown keys.
exercises[].before.lowerScientificNote	Lower Scientific Note	Required. Text.
exercises[].before.upperScientificNote	Upper Scientific Note	Required. Text.
exercises[].before.counterpointIntervalClass	Counterpoint Interval Class	Required. Text.
exercises[].before.consonantUnderTwoVoiceConvention	Consonant Under Two Voice Convention	Required. Boolean.
exercises[].before.spelledSimpleIntervalNumber	Spelled Simple Interval Number	Required. Safe integer.
exercises[].after	After	Required. Object; no unknown keys.
exercises[].after.lowerScientificNote	Lower Scientific Note	Required. Text.
exercises[].after.upperScientificNote	Upper Scientific Note	Required. Text.
exercises[].after.counterpointIntervalClass	Counterpoint Interval Class	Required. Text.
exercises[].after.consonantUnderTwoVoiceConvention	Consonant Under Two Voice Convention	Required. Boolean.
exercises[].after.spelledSimpleIntervalNumber	Spelled Simple Interval Number	Required. Safe integer.
randomness	Replay metadata: source is seed or context; seed is the normalized 32-bit seed or null for a context source.	Required. Object; no unknown keys.
randomness.seed	Optional numeric replay seed; normalization and precedence are explained below.	Required. Safe integer. or Null.
randomness.source	Source	Required. Text; one of "context", "seed".

An explicit safe-integer seed takes precedence over injected context randomness and is normalized to an unsigned 32-bit integer. With no seed and no context source, replay uses the fixed tool.io default seed. A context source must return finite values from zero inclusive to one exclusive; its advancing state must be retained separately. randomness records the source and normalized seed, or null for context. These generators are not cryptographic random sources.

json

{
  "input": {
    "count": 1,
    "midiRange": {
      "minimum": 60,
      "maximum": 72
    },
    "maximumLeapSemitones": 2,
    "lowerVoiceIsBass": true,
    "seed": 42
  },
  "output": {
    "exercises": [
      {
        "firstVoiceMidiPair": [
          67,
          69
        ],
        "secondVoiceMidiPair": [
          65,
          66
        ],
        "twoVoiceMotionClass": "similar",
        "firstVoiceSignedMotion": 2,
        "secondVoiceSignedMotion": 1,
        "voiceCrossingObserved": false,
        "before": {
          "lowerScientificNote": "F4",
          "upperScientificNote": "G4",
          "counterpointIntervalClass": "dissonance",
          "consonantUnderTwoVoiceConvention": false,
          "spelledSimpleIntervalNumber": 2
        },
        "after": {
          "lowerScientificNote": "F#4",
          "upperScientificNote": "A4",
          "counterpointIntervalClass": "imperfect-consonance",
          "consonantUnderTwoVoiceConvention": true,
          "spelledSimpleIntervalNumber": 3
        }
      }
    ],
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

The bounded pitch span is at most four octaves for the imported interval classifier. These are two-voice transitions, not complete compositional voice-leading rules, notation engraving or an audio performance.
A replay requires the same complete input and implementation. Randomized construction does not guarantee uniform coverage of every feasible output; finite samples can repeat unless a distinct-selection rule is explicitly stated.
The field tables state structural bounds; cross-field constraints and bounded search or output budgets also apply. Unknown keys are rejected where the object contract disallows them. Input errors are distinct from null fields and deliberate invalid controls in a successful output.

Alternative or Complementary methods

For a supplied example, inspect the returned construction or delegated check directly. To evaluate a consumer, also test cases chosen for its own boundaries; a generated finite corpus does not establish exhaustive coverage.

References

Tool behavior and example: Random Voice Leading Motion Exercise Generator — tool.io
Calculation or validation: music/voice-leading-motion-classifier — tool.io
Calculation or validation: music/counterpoint-consonance-classifier — tool.io

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