tone/Tone/component/LowpassCombFilter.js

A Web Audio framework for making interactive music in the browser.

import Tone from "../core/Tone";
import "../signal/Signal";
import "../component/Filter";
import "../core/AudioNode";
import "../component/FeedbackCombFilter";

/**
 *  @class Tone.Lowpass is a lowpass feedback comb filter. It is similar to
 *         Tone.FeedbackCombFilter, but includes a lowpass filter.
 *
 *  @extends {Tone.AudioNode}
 *  @constructor
 *  @param {Time|Object} [delayTime] The delay time of the comb filter
 *  @param {NormalRange=} resonance The resonance (feedback) of the comb filter
 *  @param {Frequency=} dampening The cutoff of the lowpass filter dampens the
 *                                signal as it is fedback.
 */
Tone.LowpassCombFilter = function(){

	var options = Tone.defaults(arguments, ["delayTime", "resonance", "dampening"], Tone.LowpassCombFilter);
	Tone.AudioNode.call(this);

	/**
	 *  the delay node
	 *  @type {DelayNode}
	 *  @private
	 */
	this._combFilter = this.output = new Tone.FeedbackCombFilter(options.delayTime, options.resonance);

	/**
	 *  The delayTime of the comb filter.
	 *  @type {Time}
	 *  @signal
	 */
	this.delayTime = this._combFilter.delayTime;

	/**
	 *  the lowpass filter
	 *  @type  {BiquadFilterNode}
	 *  @private
	 */
	this._lowpass = this.input = new Tone.Filter({
		"frequency" : options.dampening,
		"type" : "lowpass",
		"Q" : 0,
		"rolloff" : -12
	});

	/**
	 *  The dampening control of the feedback
	 *  @type {Frequency}
	 *  @signal
	 */
	this.dampening = this._lowpass.frequency;
	
	/**
	 *  The amount of feedback of the delayed signal.
	 *  @type {NormalRange}
	 *  @signal
	 */
	this.resonance = this._combFilter.resonance;

	//connections
	this._lowpass.connect(this._combFilter);
	this._readOnly(["dampening", "resonance", "delayTime"]);
};

Tone.extend(Tone.LowpassCombFilter, Tone.AudioNode);

/**
 *  the default parameters
 *  @static
 *  @const
 *  @type {Object}
 */
Tone.LowpassCombFilter.defaults = {
	"delayTime" : 0.1,
	"resonance" : 0.5,
	"dampening" : 3000
};

/**
 *  Clean up.
 *  @returns {Tone.LowpassCombFilter} this
 */
Tone.LowpassCombFilter.prototype.dispose = function(){
	Tone.AudioNode.prototype.dispose.call(this);
	this._writable(["dampening", "resonance", "delayTime"]);
	this._combFilter.dispose();
	this._combFilter = null;
	this.resonance = null;
	this.delayTime = null;
	this._lowpass.dispose();
	this._lowpass = null;
	this.dampening = null;
	return this;
};

export default Tone.LowpassCombFilter;