Kaona has announced its B.A.C.H. melodic, harmonic and rhythmic generator Eurorack module, which can generate over four tracks and gain feedback from the pitch, duration and dynamics of the existing track activity, plus compositional rules and constraints defined by the musician.
There are a dozen compositional languages (CL) which deliver very different results. Each has its own musical grammar and vocabulary, and so creates music in a certain compositional style. That said, Kaona points out that the module doesn’t seek to reproduce particular methods or styles, but offers an interface built on concepts.
It doesn’t use AI and what it produces would not be considered “finished”, but it offers musicians another way of generating ideas from simple inputs.
In addition, eight musical controls function in much the same way regardless of which CL is being used, and further shape what is generated. They can be driven by CV. They control such parameters as persistence, development, transformation, density, tension, and the relationships between voices and expressive gesture.
As a starting point, one of fourteen scales can be chosen, along with note durations, velocity behaviours, ornaments, swing and time signatures. The length of a total creation can be set to one bar, multiples of two up to 32 bars, or to infinite development.
A harmonic sequencer allows the construction of up to 64 chord positions with relative root, quality, duration and inversion, with a voicing mode that automatically finds the shortest movement between the four voices. The library contains 96 chord progressions and 24 explicit chord qualities.
The B.A.C.H. has eight CV inputs, dedicate clock, play/stop, reset and break inputs, gate, pitch and mod output per channel, and MIDI connections. The module itself makes no sound of its own – it must be connected to one or more VCOs, external synths or MIDI instrument to hear what it produces.
If this sounds complicated, then perhaps it is. Writing about something not physically in front of me, without the ability to experiment, makes everything feel a little abstract. In fact, the manual clearly says “B.A.C.H. is an instrument with many settings, allowing new ways of composing, improvising or accompanying to be explored. Although producing the first sequences is very simple and quick, B.A.C.H. may require a real learning period before all its subtleties are mastered.”
B.A.C.H. vs Sequencer
Explaining the difference between B.A.C.H. and a traditional sequencer, Kaona explains that a sequencer requires every note to be entered (notwithstanding plugins and other tools which can take basic sequencer input and manipulate on the fly). B.A.C.H. is a generator — you no longer enter the notes but the conditions that produce them — so you lose the ability to precisely placing certain notes in certain places.
B.A.C.H. builds on a long historical tradition of composing music from rules, which dates back to at least the eleventh century. The downloadable manual has a very interesting section on the history of generative music.
Compositional Languages
The twelve CLs are defined as:
- FUGUE constructs a multi-voice exposition from a subject, answers, a countersubject and episodes.
- CANON develops a leading line through imitation, transposition, delay, contrary motion, retrograde or augmentation.
- PROBA uses Markov chains and several transition vocabularies to produce directed randomness.
- TINTINNABULI combines a melodic voice with voices whose notes are drawn from a triad or the current chord.
- MINIMAL applies gradual processes of phase shifting, addition, substitution and hocketing.
- CELLULAR turns the evolution of a cellular automaton into musical material. It provides access to 254 rules.
- TREE interprets L-systems and their branching structures as melodic paths.
- FRACTAL uses recursive sequences and chaotic systems, including Thue–Morse, Fibonacci, Sierpi?ski and the logistic map.
- MOTIF develops chains of melodic and rhythmic cells drawn from 32 collections.
- HYBRID distributes several composition engines across the four voices.
- GROOVE organises four rhythmic roles using 64 structures.
- GROOVE MIX applies these rhythmic structures to pitches produced by an associated melodic language.
Musical Controls
The eight musical controls are:
- MATERIAL selects the vocabulary or initial rule.
- MEMORY controls persistence and the rate at which the material is renewed.
- GROWTH shapes the development and length of the form.
- MORPH introduces rotations, inversions, shifts or mutations.
- DENSITY determines the number of events and audible voices.
- TENSION gradually moves the material away from its stable state.
- INTERACTION organises the relationships between the four tracks.
- HUMANIZE introduces performance gestures specific to each language.
Availability
Expected to be available in the middle of October, the B.A.C.H. can be preordered now at a 15% discount. Pricing around €594.
