Oedipa

Oedipa takes a MIDI chord from your DAW and walks it across a lattice of chords, one step at a time. At each step it does one of three small moves — P, L, or R — that swap a single note of the chord, landing on the neighboring chord. You arrange a short cyclic pattern, and for each cell pick its move (P / L / R, or hold, or rest) and set velocity, gate, probability, and a small timing offset. All of these can be automated from your DAW.

These three moves are the neo-Riemannian P / L / R transforms, and the space of chords they connect is called the Tonnetz — a triangular lattice where every adjacent pair of chords is one move apart. Raise the jitter knob and each step’s move is picked at random from P, L, R, or hold. Fix the seed and the same input plays back identically every time.

How the chord sounds is decided by two more settings. RHYTHM sets when within each cell the notes fire (legato / onbeat / offbeat / syncopated / turing), and ARP switches between playing the chord as a block or breaking it into one note at a time. With turing, a shift register evolves the firing pattern over time.

Inspired by Automatonnetz on Ornament & Crime.