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krach

Live coding audio system. Define synths in Python, sequence them with composable patterns, hear them instantly.

# Define a synth — just a Python function
def acid_bass() -> krs.Signal:
    freq = krs.control("freq", 55.0, 20.0, 800.0)
    gate = krs.control("gate", 0.0, 0.0, 1.0)
    cutoff = krs.control("cutoff", 800.0, 100.0, 4000.0)
    env = krs.adsr(0.005, 0.15, 0.3, 0.08, gate)
    return krs.lowpass(krs.saw(freq), cutoff) * env * 0.55

# Define an effect — takes audio input
def reverb(inp: krs.Signal) -> krs.Signal:
    room = krs.control("room", 0.7, 0.0, 1.0)
    return krs.reverb(inp, room) * 0.8

# Create nodes, route, play
bass = kr.node("bass", acid_bass, gain=0.3)
verb = kr.node("verb", reverb, gain=0.3)
bass >> verb                                       # route signal
bass @ kr.seq("A2", "D3", None, "E2").over(2)      # play pattern
bass["cutoff"] = 1200                               # set control

What makes krach different

  • Graph-first API — everything is a node. >> routes signal, @ plays patterns, [] gets/sets controls.
  • Synths are Python functions — write DSP code, it compiles to FAUST and JIT-compiles to native audio via LLVM. Hot reload on save.
  • Patterns are composable — TidalCycles-inspired algebra. + sequences, | layers, .over() stretches, .swing() grooves.
  • One process, zero latency — Rust engine runs pattern sequencer + audio graph + FAUST JIT in a single binary. Python only sends pattern IR once — all per-cycle work is Rust.
  • Two symbols — kr (the audio graph) and krs (DSP primitives). That's the entire API.