tone
Version:
A Web Audio framework for making interactive music in the browser.
76 lines • 2.52 kB
JavaScript
import { ToneAudioNode, } from "../../core/context/ToneAudioNode.js";
import { GreaterThan } from "../../signal/GreaterThan.js";
import { Gain } from "../../core/context/Gain.js";
import { Follower } from "../analysis/Follower.js";
import { optionsFromArguments } from "../../core/util/Defaults.js";
import { dbToGain, gainToDb } from "../../core/type/Conversions.js";
/**
* Gate only passes a signal through when the incoming
* signal exceeds a specified threshold. It uses {@link Follower} to follow the ampltiude
* of the incoming signal and compares it to the {@link threshold} value using {@link GreaterThan}.
*
* @example
* const gate = new Tone.Gate(-30, 0.2).toDestination();
* const mic = new Tone.UserMedia().connect(gate);
* // the gate will only pass through the incoming
* // signal when it's louder than -30db
* @category Component
*/
export class Gate extends ToneAudioNode {
constructor() {
const options = optionsFromArguments(Gate.getDefaults(), arguments, [
"threshold",
"smoothing",
]);
super(options);
this.name = "Gate";
this._follower = new Follower({
context: this.context,
smoothing: options.smoothing,
});
this._gt = new GreaterThan({
context: this.context,
value: dbToGain(options.threshold),
});
this.input = new Gain({ context: this.context });
this._gate = this.output = new Gain({ context: this.context });
// connections
this.input.connect(this._gate);
// the control signal
this.input.chain(this._follower, this._gt, this._gate.gain);
}
static getDefaults() {
return Object.assign(ToneAudioNode.getDefaults(), {
smoothing: 0.1,
threshold: -40,
});
}
/**
* The threshold of the gate in decibels
*/
get threshold() {
return gainToDb(this._gt.value);
}
set threshold(thresh) {
this._gt.value = dbToGain(thresh);
}
/**
* The attack/decay speed of the gate.
* @see {@link Follower.smoothing}
*/
get smoothing() {
return this._follower.smoothing;
}
set smoothing(smoothingTime) {
this._follower.smoothing = smoothingTime;
}
dispose() {
super.dispose();
this.input.dispose();
this._follower.dispose();
this._gt.dispose();
this._gate.dispose();
return this;
}
}
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