Live params, modulation and observability

Every Faust UI element in your source is live twice over: as a knob in the module panel, and as a param path for actions.

• dsp.param.set { module_id, path, value } — push a value into the running worklet. Paths are the literal Faust addresses from documents.list (e.g. /MyDsp/cutoff). No-op when stopped.
• dsp.param.get { module_id, path } — read the live, post-modulation value the knob currently shows. (Poly magic params are the exception — see the MIDI section.)

#Being modulated

A running DSP's params register as modulation sinks — any LFO or modulation source in the Patchbay can drive them. Modulation is non-destructive: the engine computes clamp(base + Σ amount × source), so removing an edge restores your base value. Depth lives on the edge (routing.connect { kind: "modulation", amount } / routing.set).

#Being a modulator

Tag a bargraph with the [modout] metadata and your DSP becomes a modulation source — DSP A's envelope follower can wobble DSP B's filter:

process = sig <: _, (an.amp_follower(0.05) : hbargraph("env [modout]", 0, 1) : !);

Every [modout] output appears as a source port in the Patchbay while the DSP runs.

#Watching without eyes

• documents.list — runtime state of every open DSP (status, compile error, params, polyphonic, midi_channel).
• system.state { sections: ["master"] } — master meters (read them while sound plays — see Hearing is proof).
• logs.get { level: "error" } — the renderer log; compile and runtime failures the UI shows land here too.