Species, voice leading, listening

Counterpoint Generator

Generate counterpoint above or below a cantus firmus, inspect rule diagnostics, listen to the line, lock useful measures and export MusicXML or MIDI.

Composition workspace

Write a voice, then inspect how it behaves

Cantus

The fixed line should already sing

Good counterpoint does not repair a directionless cantus with a confused climax or weak cadence.

Report

No alerts is not an artwork

The validator catches immediate problems; it does not judge style, breath, phrasing or beauty.

Ready.

Cantus Input

Enter note names separated by spaces, for example: D4 E4 F4 G4 A4 G4 F4 E4 D4
Import up to 64 pitches, one note per bar. Rests and rhythm are ignored; chords use their highest note.
Select a key...

Bar Locks

Lock bars you want to keep before rerolling weak spots.
Generate a result to manage bar locks.

Generator Settings

Theory Rules / Playback tempo
100 BPM
Controls playback and MIDI export speed in BPM.
72%
Higher values favor smoother conjunct motion.
70%
Higher values favor contrary motion against the cantus.
20%
Higher values allow more tension where the selected species permits it.

Generated Counterpoint

Composition workspace

Understand counterpoint before keeping a generation

Horizontal and vertical

Counterpoint follows independent lines through time while controlling the vertical intervals formed when voices meet.

Species and styles

Species isolate pedagogical behaviors: 1:1, 2:1, 4:1, suspensions and florid counterpoint. They do not summarize all Renaissance, tonal or modern writing.

Rules and preferences

Some constraints block candidates; others guide scoring or create a diagnostic warning after generation.

Practice method

  • Sing the cantus alone before generating.
  • Compare contrary, similar and oblique motion measure by measure.
  • Treat dissonances according to species and metric placement.
  • Export only lines you can explain and sing.

The five supported species

Species 1-5

The interface exposes the five pedagogical species. Their purpose is to isolate rhythmic and contrapuntal behavior, not to summarize the whole history of counterpoint.

MusicXML and MIDI output follow the selected model: first species 1:1, second 2:1, third 4:1, fourth with suspensions, fifth florid.

Species Organization Principle
1 1:1 Every counterpoint note aligns with one cantus note; structural intervals must be consonant.
2 2:1 Strong positions stay consonant; weak positions may use controlled passing dissonance.
3 4:1 Faster motion permits passing and neighbor activity while strong positions remain clear.
4 Suspensions Prepared notes are tied over, become dissonant, then resolve downward by step.
5 Florid Mixed rhythmic behavior combines habits from the earlier species.

Consonance, dissonance and motion

Analysis

Unisons, fifths and octaves are perfect consonances; thirds and sixths are imperfect consonances. Seconds, sevenths, tritones and the fourth above the bass require contextual treatment.

The engine distinguishes contrary, similar and oblique motion, then reports issues such as perfect parallels, direct perfects, crossing and overlap.

Case Notes Reading
Parallel fifths Lower C3-D3, upper G3-A3 P5 to P5 with both voices ascending; independence weakens.
Contrary motion Lower C3-D3, upper E4-D4 One voice rises while the other falls; useful but not automatically valid.
Oblique motion Lower C3-C3, upper E4-F4 One voice holds while the other moves.
Fourth above bass C3-F3 Context-dependent: often treated as dissonant in two-voice species practice.

Rule report

Diagnostic

The report describes measurable risks: perfect parallels, direct perfects, unresolved leaps, weak-beat dissonance, spacing, crossing, climax and cadence.

With multiple generated voices, diagnostics build a shared timeline and compare simultaneous voices pair by pair: cantus with generated voices, adjacent voices and non-adjacent voices. Findings remain stylistic evidence, not artistic judgment.

  • A warning is not always an absolute ban outside the selected style.
  • No warning does not guarantee an expressive line.
  • Bar locks keep a successful measure during partial regeneration.

Cantus import

MIDI/MusicXML

Import reads MIDI, MusicXML or MXL as cantus material. It reduces the source to a monophonic line for the exercise.

  • Up to 64 pitches are retained.
  • Original rhythm and rests are ignored.
  • For chords, the highest note is used.

Ten progressive exercises

Practice

Each exercise starts from a behavior that the tool can display, then asks for listening and musical explanation.

Objective Source Instruction Success
Consonant intervals C3 cantus Name unison, third, fifth, sixth and octave above each note. You can identify perfect and imperfect consonances without the report.
Motion types C3-D3 under E4-D4 Classify contrary, similar, parallel and oblique motion. You can explain why contrary motion helps but is not sufficient.
First species D4 E4 F4 G4 A4 G4 F4 E4 D4 Generate 1:1 above the cantus and sing both lines separately. Every exposed vertical interval is intentional.
Parallel perfects Any generated line Open the report and find fifth/octave warnings. You can propose a different melodic direction.
Leap control Balanced profile Lower maximum leap and compare contour. Large leaps recover by contrary step when the rule is active.
Second species Species 2 Listen for strong and weak positions. Weak dissonance behaves like passing motion, not random color.
Third species Species 3 Check four events against each cantus note. Fast notes keep melodic shape and do not obscure the cantus.
Fourth species Species 4 Find preparation, suspension and downward resolution. You can sing the tension and release.
Fifth species Species 5 Compare florid output with stricter species. Freedom still has interval and contour discipline.
Complete passage Lock stable bars Keep good measures, regenerate weak ones, then export. The exported line can be sung and explained measure by measure.

Useful musical limits

Listening

The generator produces a proposal and a diagnostic report, not a universal stylistic authority. Tonal, modal, Renaissance and modern counterpoint do not always share the same priorities.

  • Always check whether each voice can be sung alone.
  • Compare score, audio and export before reusing a line.
  • Adapt rules to context instead of turning every recommendation into law.

Connect counterpoint, harmony and practice