A ChucK ADSR envelope or STK instrument stays silent until its gate is opened with keyOn/noteOn

In ChucK, configuring an envelope (.set(a,d,s,r)) or an STK instrument (.freq, timbre params) only sets parameters — it does not make sound. The voice stays silent until the gate is opened: an ADSR needs e.keyOn() (and e.keyOff() to release), and an STK instrument needs inst.noteOn(vel). No error is thrown; the voice simply never triggers. This is a distinct silent-failure mode from a missing dac path or a missing time advance.

Examples

ADSR e; e.set(10::ms, 8::ms, 0.5, 500::ms); alone is silent. Fix: add e.keyOn();. STK: Mandolin m => dac; m.noteOn(0.8);.

Assessment

Explain why setting an ADSR’s parameters does not produce sound in ChucK, and name the call that actually triggers the voice.