ADSR Amplifier

A Voltage Controlled Amplifier (VCA) module with an Attack-Decay-Sustain-Release (ADSR) envelope

Use it to add an envelope to the synth voices.

import { AdsrAmp, OscillatorNode } from "synthlet";
 
const osc = new OscillatorNode(audioContext, {
  frequency: 440,
});
const vca = AdsrAmp(audioContext, {
  gain: 0.5,
  attack: 0.1,
  decay: 0.1,
  sustain: 0.5,
  release: 0.1,
});
// Connect the oscillator to the VCA and to the output
osc.connect(vca).connect(audioContext.destination);
// Start the envelope (start attack phase)
vca.gate.value = 1;
// Stop the envelope (start release phase)
vca.gate.value = 0;

Parameters

Same as adsr:

• attack: The attack time in seconds. Default is 0.1.
• decay: The decay time in seconds. Default is 0.1.
• sustain: The sustain level. Default is 0.5.
• release: The release time in seconds. Default is 0.1.
• offset: The start offset. Default is 0.
• gain: The gain. Default is 1. It is the maximum amplitude after the attach and affects the sustain level. For example, a gain of 100 and sustain of 0.5 will make the sustain level to be 50.