tone
Version:
A Web Audio framework for making interactive music in the browser.
102 lines • 3.62 kB
JavaScript
import { StereoEffect } from "./StereoEffect.js";
import { optionsFromArguments } from "../core/util/Defaults.js";
import { Scale } from "../signal/Scale.js";
import { Signal } from "../signal/Signal.js";
import { FeedbackCombFilter } from "../component/filter/FeedbackCombFilter.js";
import { readOnly } from "../core/util/Interface.js";
/**
* an array of the comb filter delay time values
*/
const combFilterDelayTimes = [
1687 / 25000,
1601 / 25000,
2053 / 25000,
2251 / 25000,
];
/**
* the resonances of each of the comb filters
*/
const combFilterResonances = [0.773, 0.802, 0.753, 0.733];
/**
* the allpass filter frequencies
*/
const allpassFilterFreqs = [347, 113, 37];
/**
* JCReverb is a simple [Schroeder Reverberator](https://ccrma.stanford.edu/~jos/pasp/Schroeder_Reverberators.html)
* tuned by John Chowning in 1970.
* It is made up of three allpass filters and four {@link FeedbackCombFilter}.
* JCReverb is now implemented with an AudioWorkletNode which may result on performance degradation on some platforms. Consider using {@link Reverb}.
* @example
* const reverb = new Tone.JCReverb(0.4).toDestination();
* const delay = new Tone.FeedbackDelay(0.5);
* // connecting the synth to reverb through delay
* const synth = new Tone.DuoSynth().chain(delay, reverb);
* synth.triggerAttackRelease("A4", "8n");
*
* @category Effect
*/
export class JCReverb extends StereoEffect {
constructor() {
const options = optionsFromArguments(JCReverb.getDefaults(), arguments, ["roomSize"]);
super(options);
this.name = "JCReverb";
/**
* a series of allpass filters
*/
this._allpassFilters = [];
/**
* parallel feedback comb filters
*/
this._feedbackCombFilters = [];
this.roomSize = new Signal({
context: this.context,
value: options.roomSize,
units: "normalRange",
});
this._scaleRoomSize = new Scale({
context: this.context,
min: -0.733,
max: 0.197,
});
// make the allpass filters
this._allpassFilters = allpassFilterFreqs.map((freq) => {
const allpass = this.context.createBiquadFilter();
allpass.type = "allpass";
allpass.frequency.value = freq;
return allpass;
});
// and the comb filters
this._feedbackCombFilters = combFilterDelayTimes.map((delayTime, index) => {
const fbcf = new FeedbackCombFilter({
context: this.context,
delayTime,
});
this._scaleRoomSize.connect(fbcf.resonance);
fbcf.resonance.value = combFilterResonances[index];
if (index < combFilterDelayTimes.length / 2) {
this.connectEffectLeft(...this._allpassFilters, fbcf);
}
else {
this.connectEffectRight(...this._allpassFilters, fbcf);
}
return fbcf;
});
// chain the allpass filters together
this.roomSize.connect(this._scaleRoomSize);
readOnly(this, ["roomSize"]);
}
static getDefaults() {
return Object.assign(StereoEffect.getDefaults(), {
roomSize: 0.5,
});
}
dispose() {
super.dispose();
this._allpassFilters.forEach((apf) => apf.disconnect());
this._feedbackCombFilters.forEach((fbcf) => fbcf.dispose());
this.roomSize.dispose();
this._scaleRoomSize.dispose();
return this;
}
}
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