A pitch sweep counted down in On update or On fixed update runs in game time, while the sound runs on the clock of the audio device. A short sound magnifies any offset between the two, so the sweep came out different on every play and most of all on the first. - Set sound FX parameters has a new input time in seconds. The values run evenly to their target in that time, scheduled on the audio clock with linearRampToValueAtTime or exponentialRampToValueAtTime. - Evenly in their own unit: a pitch in semitones and a gain in decibels, an EQ band and a Mix share linearly in their value. - A time of 0 or below keeps the quick glide of about 0.1 s. - Each change starts from where the voice is now. Whatever was still planned is dropped, so a change never queues behind an older one. Firefox lacks cancelAndHoldAtTime, there the value is held by hand. - A voice still waiting on its bytes starts a timed change with the sound, so the whole sweep is heard. Tests: - node-catalog: time is handed on, a time below 0 is a quick glide. - sound-library: semitones and decibels ramp in their own steps, a timed change on a waiting voice starts with the sound. - sound-library + node-catalog + soundfx: 419 tests, green. - e2e 34 on melektaus-atx: ALL PASSED, 31 checks. A 2 s ramp from depth 7 to -5 read speed 0.979, 0.926 and 0.778 half a second on. - Counter-check: folding a timed change on a waiting voice into its start values fails the new test. - The gate did not run. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>