Tone.js/Tone/instrument/DuoSynth.js

import Tone from "../core/Tone";
import "../instrument/MonoSynth";
import "../component/LFO";
import "../signal/Signal";
import "../signal/Multiply";
import "../instrument/Monophonic";
import "../core/Param";

/**
 *  @class  Tone.DuoSynth is a monophonic synth composed of two
 *          MonoSynths run in parallel with control over the
 *          frequency ratio between the two voices and vibrato effect.
 *          <img src="https://docs.google.com/drawings/d/1bL4GXvfRMMlqS7XyBm9CjL9KJPSUKbcdBNpqOlkFLxk/pub?w=1012&h=448">
 *
 *  @constructor
 *  @extends {Tone.Monophonic}
 *  @param {Object} [options] the options available for the synth
 *                          see defaults below
 *  @example
 * var duoSynth = new Tone.DuoSynth().toMaster();
 * duoSynth.triggerAttackRelease("C4", "2n");
 */
Tone.DuoSynth = function(options){

	options = Tone.defaultArg(options, Tone.DuoSynth.defaults);
	Tone.Monophonic.call(this, options);

	/**
	 *  the first voice
	 *  @type {Tone.MonoSynth}
	 */
	this.voice0 = new Tone.MonoSynth(options.voice0);
	this.voice0.volume.value = -10;

	/**
	 *  the second voice
	 *  @type {Tone.MonoSynth}
	 */
	this.voice1 = new Tone.MonoSynth(options.voice1);
	this.voice1.volume.value = -10;

	/**
	 *  The vibrato LFO.
	 *  @type {Tone.LFO}
	 *  @private
	 */
	this._vibrato = new Tone.LFO(options.vibratoRate, -50, 50);
	this._vibrato.start();

	/**
	 * the vibrato frequency
	 * @type {Frequency}
	 * @signal
	 */
	this.vibratoRate = this._vibrato.frequency;

	/**
	 *  the vibrato gain
	 *  @type {Tone.Gain}
	 *  @private
	 */
	this._vibratoGain = new Tone.Gain(options.vibratoAmount, Tone.Type.Positive);

	/**
	 * The amount of vibrato
	 * @type {Positive}
	 * @signal
	 */
	this.vibratoAmount = this._vibratoGain.gain;

	/**
	 *  the frequency control
	 *  @type {Frequency}
	 *  @signal
	 */
	this.frequency = new Tone.Signal(440, Tone.Type.Frequency);

	/**
	 *  Harmonicity is the ratio between the two voices. A harmonicity of
	 *  1 is no change. Harmonicity = 2 means a change of an octave.
	 *  @type {Positive}
	 *  @signal
	 *  @example
	 * //pitch voice1 an octave below voice0
	 * duoSynth.harmonicity.value = 0.5;
	 */
	this.harmonicity = new Tone.Multiply(options.harmonicity);
	this.harmonicity.units = Tone.Type.Positive;

	//control the two voices frequency
	this.frequency.connect(this.voice0.frequency);
	this.frequency.chain(this.harmonicity, this.voice1.frequency);
	this._vibrato.connect(this._vibratoGain);
	this._vibratoGain.fan(this.voice0.detune, this.voice1.detune);
	this.voice0.connect(this.output);
	this.voice1.connect(this.output);
	this._readOnly(["voice0", "voice1", "frequency", "vibratoAmount", "vibratoRate"]);
};

Tone.extend(Tone.DuoSynth, Tone.Monophonic);

/**
 *  @static
 *  @type {Object}
 */
Tone.DuoSynth.defaults = {
	"vibratoAmount" : 0.5,
	"vibratoRate" : 5,
	"harmonicity" : 1.5,
	"voice0" : {
		"volume" : -10,
		"portamento" : 0,
		"oscillator" : {
			"type" : "sine"
		},
		"filterEnvelope" : {
			"attack" : 0.01,
			"decay" : 0.0,
			"sustain" : 1,
			"release" : 0.5
		},
		"envelope" : {
			"attack" : 0.01,
			"decay" : 0.0,
			"sustain" : 1,
			"release" : 0.5
		}
	},
	"voice1" : {
		"volume" : -10,
		"portamento" : 0,
		"oscillator" : {
			"type" : "sine"
		},
		"filterEnvelope" : {
			"attack" : 0.01,
			"decay" : 0.0,
			"sustain" : 1,
			"release" : 0.5
		},
		"envelope" : {
			"attack" : 0.01,
			"decay" : 0.0,
			"sustain" : 1,
			"release" : 0.5
		}
	}
};

/**
 *  start the attack portion of the envelopes
 *
 *  @param {Time} [time=now] the time the attack should start
 *  @param {NormalRange} [velocity=1] the velocity of the note (0-1)
 *  @returns {Tone.DuoSynth} this
 *  @private
 */
Tone.DuoSynth.prototype._triggerEnvelopeAttack = function(time, velocity){
	time = this.toSeconds(time);
	this.voice0._triggerEnvelopeAttack(time, velocity);
	this.voice1._triggerEnvelopeAttack(time, velocity);
	return this;
};

/**
 *  start the release portion of the envelopes
 *
 *  @param {Time} [time=now] the time the release should start
 *  @returns {Tone.DuoSynth} this
 *  @private
 */
Tone.DuoSynth.prototype._triggerEnvelopeRelease = function(time){
	this.voice0._triggerEnvelopeRelease(time);
	this.voice1._triggerEnvelopeRelease(time);
	return this;
};

/**
 *  Get the level of the output at the given time. Measures
 *  the envelope(s) value at the time. 
 *  @param {Time} time The time to query the envelope value
 *  @return {NormalRange} The output level between 0-1
 */
Tone.DuoSynth.prototype.getLevelAtTime = function(time){
	return (this.voice0.getLevelAtTime(time) + this.voice1.getLevelAtTime(time))/2;
};

/**
 *  clean up
 *  @returns {Tone.DuoSynth} this
 */
Tone.DuoSynth.prototype.dispose = function(){
	Tone.Monophonic.prototype.dispose.call(this);
	this._writable(["voice0", "voice1", "frequency", "vibratoAmount", "vibratoRate"]);
	this.voice0.dispose();
	this.voice0 = null;
	this.voice1.dispose();
	this.voice1 = null;
	this.frequency.dispose();
	this.frequency = null;
	this._vibratoGain.dispose();
	this._vibratoGain = null;
	this._vibrato = null;
	this.harmonicity.dispose();
	this.harmonicity = null;
	this.vibratoAmount.dispose();
	this.vibratoAmount = null;
	this.vibratoRate = null;
	return this;
};

export default Tone.DuoSynth;