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clean up and convert webaudio nodes to tone js objects

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This commit is contained in:
Eric Rosenbaum 2016-11-08 17:29:02 -05:00
parent b0786e6dbf
commit 7a25ced256
1 changed files with 24 additions and 109 deletions
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133
src/vocoder.js
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@ -1,3 +1,7 @@
/*
*/
var Tone = require('tone');
function Vocoder () {
@ -25,9 +29,8 @@ Vocoder.prototype.setCarrierOscFrequency = function (freq) {
this.oscillatorNode.frequency.rampTo(freq, 0.05);
};
// this function will algorithmically re-calculate vocoder bands, distributing evenly
// this function algorithmically calculates vocoder bands, distributing evenly
// from startFreq to endFreq, splitting evenly (logarhythmically) into a given numBands.
// The function places this info into the vocoderBands and numVocoderBands variables.
Vocoder.prototype.generateVocoderBands = function (startFreq, endFreq, numBands) {
// Remember: 1200 cents in octave, 100 cents per semitone
@ -41,7 +44,6 @@ Vocoder.prototype.generateVocoderBands = function (startFreq, endFreq, numBands)
for (var i=0; i<numBands; i++) {
vocoderBands[i] = new Object();
vocoderBands[i].frequency = currentFreq;
//console.log( "Band " + i + " centered at " + currentFreq + "Hz" );
currentFreq = currentFreq * scale;
}
@ -50,149 +52,62 @@ Vocoder.prototype.generateVocoderBands = function (startFreq, endFreq, numBands)
Vocoder.prototype.initBandpassFilters = function () {
var modFilterBands = new Array(); // tuned bandpass filters
var modFilterPostGains = new Array(); // post-filter gains.
var heterodynes = new Array(); // gain nodes used to multiply bandpass X sine
var powers = new Array(); // gain nodes used to multiply prev out by itself
var lpFilters = new Array(); // tuned lowpass filters to remove doubled copy of product
var lpFilterPostGains = new Array(); // gain nodes for tuning input to waveshapers
var carrierBands = new Array(); // tuned bandpass filters, same as modFilterBands but in carrier chain
var carrierFilterPostGains = new Array(); // post-bandpass gain adjustment
var carrierBandGains = new Array(); // these are the "control gains" driven by the lpFilters
var waveShaperCurve = new Float32Array(65536);
// Populate with a "curve" that does an abs()
var n = 65536;
var n2 = n / 2;
for (var i = 0; i < n2; ++i) {
var x = i / n2;
waveShaperCurve[n2 + i] = x;
waveShaperCurve[n2 - i - 1] = x;
}
// Set up a high-pass filter to add back in the fricatives, etc.
var hpFilter = Tone.context.createBiquadFilter();
hpFilter.type = 'highpass';
hpFilter.frequency.value = 8000;
hpFilter.Q.value = 1; // no peaking
this.modulatorInput.connect( hpFilter);
var hpFilter = new Tone.Filter(8000, 'highpass');
this.modulatorInput.connect(hpFilter);
hpFilter.connect(this.outputGain);
var hpFilterGain = Tone.context.createGain();
hpFilterGain.gain.value = 1.0;
for (var i=0; i<this.vocoderBands.length; i++) {
hpFilter.connect(hpFilterGain);
hpFilterGain.connect(this.outputGain);
//clear the arrays
modFilterBands.length = 0;
modFilterPostGains.length = 0;
heterodynes.length = 0;
powers.length = 0;
lpFilters.length = 0;
lpFilterPostGains.length = 0;
carrierBands.length = 0;
carrierFilterPostGains.length = 0;
carrierBandGains.length = 0;
var rectifierCurve = new Float32Array(65536);
for (i=-32768; i<32768; i++) {
rectifierCurve[i+32768] = ((i>0)?i:-i)/32768;
}
for (i=0; i<this.vocoderBands.length; i++) {
// CREATE THE MODULATOR CHAIN
// create the bandpass filter in the modulator chain
var modulatorFilter = Tone.context.createBiquadFilter();
modulatorFilter.type = 'bandpass'; // Bandpass filter
modulatorFilter.frequency.value = this.vocoderBands[i].frequency;
modulatorFilter.Q.value = this.FILTER_QUALITY; // initial quality
var modulatorFilter = new Tone.Filter(this.vocoderBands[i].frequency, 'bandpass', -24);
modulatorFilter.Q.value = this.FILTER_QUALITY;
this.modulatorInput.connect(modulatorFilter);
modFilterBands.push(modulatorFilter);
// Now, create a second bandpass filter tuned to the same frequency -
// this turns our second-order filter into a 4th-order filter,
// which has a steeper rolloff/octave
var secondModulatorFilter = Tone.context.createBiquadFilter();
secondModulatorFilter.type = 'bandpass'; // Bandpass filter
secondModulatorFilter.frequency.value = this.vocoderBands[i].frequency;
secondModulatorFilter.Q.value = this.FILTER_QUALITY; // initial quality
modulatorFilter.chainedFilter = secondModulatorFilter;
modulatorFilter.connect(secondModulatorFilter);
// create a post-filtering gain to bump the levels up.
var modulatorFilterPostGain = Tone.context.createGain();
var modulatorFilterPostGain = new Tone.Gain();
modulatorFilterPostGain.gain.value = 6;
secondModulatorFilter.connect(modulatorFilterPostGain);
modFilterPostGains.push(modulatorFilterPostGain);
modulatorFilter.connect(modulatorFilterPostGain);
// Create the sine oscillator for the heterodyne
var heterodyneOscillator = Tone.context.createOscillator();
heterodyneOscillator.frequency.value = this.vocoderBands[i].frequency;
heterodyneOscillator.start(0);
var heterodyneOscillator = new Tone.Oscillator(this.vocoderBands[i].frequency).start();
// Create the node to multiply the sine by the modulator
var heterodyne = Tone.context.createGain();
var heterodyne = new Tone.Gain(0); // audio-rate inputs are summed with initial intrinsic value
modulatorFilterPostGain.connect(heterodyne);
heterodyne.gain.value = 0.0; // audio-rate inputs are summed with initial intrinsic value
heterodyneOscillator.connect(heterodyne.gain);
var heterodynePostGain = Tone.context.createGain();
heterodynePostGain.gain.value = 2.0; // GUESS: boost
var heterodynePostGain = new Tone.Gain(2.0);
heterodyne.connect(heterodynePostGain);
heterodynes.push(heterodynePostGain);
// Create the rectifier node
var rectifier = Tone.context.createWaveShaper();
rectifier.curve = rectifierCurve;
var rectifier = new Tone.WaveShaper([1, 0, 1]);
heterodynePostGain.connect(rectifier);
// Create the lowpass filter to mask off the difference (near zero)
var lpFilter = Tone.context.createBiquadFilter();
lpFilter.type = "lowpass"; // Lowpass filter
lpFilter.frequency.value = 5.0; // Guesstimate! Mask off 20Hz and above.
var lpFilter = new Tone.Filter(5, 'lowpass');
lpFilter.Q.value = 1; // don't need a peak
lpFilters.push(lpFilter);
rectifier.connect(lpFilter);
var lpFilterPostGain = Tone.context.createGain();
var lpFilterPostGain = new Tone.Gain();
lpFilterPostGain.gain.value = 1.0;
lpFilter.connect(lpFilterPostGain);
lpFilterPostGains.push(lpFilterPostGain);
var waveshaper = Tone.context.createWaveShaper();
waveshaper.curve = waveShaperCurve;
var waveshaper = new Tone.WaveShaper([1, 0, 1]);
lpFilterPostGain.connect(waveshaper);
// Create the bandpass filter in the carrier chain
var carrierFilter = Tone.context.createBiquadFilter();
carrierFilter.type = 'bandpass';
carrierFilter.frequency.value = this.vocoderBands[i].frequency;
var carrierFilter = new Tone.Filter(this.vocoderBands[i].frequency, 'bandpass', -24);
carrierFilter.Q.value = this.FILTER_QUALITY;
carrierBands.push(carrierFilter);
this.carrierInput.connect(carrierFilter);
// We want our carrier filters to be 4th-order filter too.
var secondCarrierFilter = Tone.context.createBiquadFilter();
secondCarrierFilter.type = 'bandpass'; // Bandpass filter
secondCarrierFilter.frequency.value = this.vocoderBands[i].frequency;
secondCarrierFilter.Q.value = this.FILTER_QUALITY; // initial quality
carrierFilter.chainedFilter = secondCarrierFilter;
carrierFilter.connect(secondCarrierFilter);
var carrierFilterPostGain = Tone.context.createGain();
carrierFilterPostGain.gain.value = 10.0;
secondCarrierFilter.connect(carrierFilterPostGain);
carrierFilterPostGains.push(carrierFilterPostGain);
var carrierFilterPostGain = new Tone.Gain(10);
carrierFilter.connect(carrierFilterPostGain);
// Create the carrier band gain node
var bandGain = Tone.context.createGain();
carrierBandGains.push(bandGain);
var bandGain = new Tone.Gain(0); // audio-rate inputs are summed with initial intrinsic value
carrierFilterPostGain.connect(bandGain);
bandGain.gain.value = 0.0; // audio-rate inputs are summed with initial intrinsic value
waveshaper.connect(bandGain.gain); // connect the lp controller
bandGain.connect(this.outputGain);