tone
Version:
A Web Audio framework for making interactive music in the browser.
162 lines • 5.1 kB
JavaScript
import { StereoFeedbackEffect, } from "../effect/StereoFeedbackEffect.js";
import { optionsFromArguments } from "../core/util/Defaults.js";
import { LFO } from "../source/oscillator/LFO.js";
import { Delay } from "../core/context/Delay.js";
import { readOnly } from "../core/util/Interface.js";
/**
* Chorus is a stereo chorus effect composed of a left and right delay with an {@link LFO} applied to the delayTime of each channel.
* When {@link feedback} is set to a value larger than 0, you also get Flanger-type effects.
* Inspiration from [Tuna.js](https://github.com/Dinahmoe/tuna/blob/master/tuna.js).
* Read more on the chorus effect on [Sound On Sound](http://www.soundonsound.com/sos/jun04/articles/synthsecrets.htm).
*
* @example
* const chorus = new Tone.Chorus(4, 2.5, 0.5).toDestination().start();
* const synth = new Tone.PolySynth().connect(chorus);
* synth.triggerAttackRelease(["C3", "E3", "G3"], "8n");
*
* @category Effect
*/
export class Chorus extends StereoFeedbackEffect {
constructor() {
const options = optionsFromArguments(Chorus.getDefaults(), arguments, [
"frequency",
"delayTime",
"depth",
]);
super(options);
this.name = "Chorus";
this._depth = options.depth;
this._delayTime = options.delayTime / 1000;
this._lfoL = new LFO({
context: this.context,
frequency: options.frequency,
min: 0,
max: 1,
});
this._lfoR = new LFO({
context: this.context,
frequency: options.frequency,
min: 0,
max: 1,
phase: 180,
});
this._delayNodeL = new Delay({ context: this.context });
this._delayNodeR = new Delay({ context: this.context });
this.frequency = this._lfoL.frequency;
readOnly(this, ["frequency"]);
// have one LFO frequency control the other
this._lfoL.frequency.connect(this._lfoR.frequency);
// connections
this.connectEffectLeft(this._delayNodeL);
this.connectEffectRight(this._delayNodeR);
// lfo setup
this._lfoL.connect(this._delayNodeL.delayTime);
this._lfoR.connect(this._delayNodeR.delayTime);
// set the initial values
this.depth = this._depth;
this.type = options.type;
this.spread = options.spread;
}
static getDefaults() {
return Object.assign(StereoFeedbackEffect.getDefaults(), {
frequency: 1.5,
delayTime: 3.5,
depth: 0.7,
type: "sine",
spread: 180,
feedback: 0,
wet: 0.5,
});
}
/**
* The depth of the effect. A depth of 1 makes the delayTime
* modulate between 0 and 2*delayTime (centered around the delayTime).
*/
get depth() {
return this._depth;
}
set depth(depth) {
this._depth = depth;
const deviation = this._delayTime * depth;
this._lfoL.min = Math.max(this._delayTime - deviation, 0);
this._lfoL.max = this._delayTime + deviation;
this._lfoR.min = Math.max(this._delayTime - deviation, 0);
this._lfoR.max = this._delayTime + deviation;
}
/**
* The delayTime in milliseconds of the chorus. A larger delayTime
* will give a more pronounced effect. Nominal range a delayTime
* is between 2 and 20ms.
*/
get delayTime() {
return this._delayTime * 1000;
}
set delayTime(delayTime) {
this._delayTime = delayTime / 1000;
this.depth = this._depth;
}
/**
* The oscillator type of the LFO.
*/
get type() {
return this._lfoL.type;
}
set type(type) {
this._lfoL.type = type;
this._lfoR.type = type;
}
/**
* Amount of stereo spread. When set to 0, both LFO's will be panned centrally.
* When set to 180, LFO's will be panned hard left and right respectively.
*/
get spread() {
return this._lfoR.phase - this._lfoL.phase;
}
set spread(spread) {
this._lfoL.phase = 90 - spread / 2;
this._lfoR.phase = spread / 2 + 90;
}
/**
* Start the effect.
*/
start(time) {
this._lfoL.start(time);
this._lfoR.start(time);
return this;
}
/**
* Stop the lfo
*/
stop(time) {
this._lfoL.stop(time);
this._lfoR.stop(time);
return this;
}
/**
* Sync the filter to the transport.
* @see {@link LFO.sync}
*/
sync() {
this._lfoL.sync();
this._lfoR.sync();
return this;
}
/**
* Unsync the filter from the transport.
*/
unsync() {
this._lfoL.unsync();
this._lfoR.unsync();
return this;
}
dispose() {
super.dispose();
this._lfoL.dispose();
this._lfoR.dispose();
this._delayNodeL.dispose();
this._delayNodeR.dispose();
this.frequency.dispose();
return this;
}
}
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