Bad Bach is a crude attempt to produce "bad" first-species counterpoint which deliberately breaks the counterpoint rules. It uses the library https://bspaans.github.io/python-mingus.
The rules for First-Species Counterpoint (Graduate Review of Tonal Theory, p. 28):
- All harmonic intervals must be consonances (P8, P5, P1, M3, m3, M6, m6).
- Parallel perfect intervals are forbidden.
- Direct fifths and octaves are forbidden except when the soprano voice moves by a step.
- Lower voice must begin on 1, upper voice can be begin on 1, 3, or 5. Both voices end on 1.
- Unisons are allowed only at the beginning and end.
- In minor keys, raise 6 and 7 only if they immediately precede the cadence.
Implemented:
- Non-deterministic music generation which prefers counterpoint lines which violate the first five rules of first species counterpoint. (The sixth rule applies to minor keys, which are not implemented.)
- Melody composition with
create_melodyfunction, which takes a list of notes, each of which is expressed as a string.
Roadmap, not implemented:
- Support for accidentals and keys other than major C.
- Support for rhythm and higher-species counterpoint.
- UI for composing or importing melodies.