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simplified signal processing

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This commit is contained in:
Eric Rosenbaum 2016-11-10 13:49:11 -05:00
parent 99bbdeb873
commit 4deff78059
1 changed files with 14 additions and 29 deletions
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43
src/vocoder.js
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@ -1,6 +1,9 @@
/*
This is a port of Jamison Dance's port of Chris Wilson's WebAudio vocoder.
This is a port of Jamison Dance's port of Chris Wilson's WebAudio vocoder:
https://github.com/jergason/Vocoder
https://github.com/cwilso/Vocoder
I have adapted it to use the ToneJs library, making it a Tone Effect that
can be added to an audio effects chain.
@ -43,7 +46,7 @@ function Vocoder () {
this.oscillatorNode;
this.vocoderBands = this.generateVocoderBands(55, 7040, 10);
this.vocoderBands = this.generateVocoderBands(55, 7040, 8);
this.initBandpassFilters();
this.createCarrier();
@ -99,31 +102,12 @@ Vocoder.prototype.initBandpassFilters = function () {
var modulatorFilterPostGain = new Tone.Gain(6);
modulatorFilter.connect(modulatorFilterPostGain);
// Create the sine oscillator for the heterodyne
var heterodyneOscillator = new Tone.Oscillator(this.vocoderBands[i].frequency).start();
// Create the node to multiply the sine by the modulator
var heterodyne = new Tone.Gain(0); // audio-rate inputs are summed with initial intrinsic value
modulatorFilterPostGain.connect(heterodyne);
heterodyneOscillator.connect(heterodyne.gain);
var heterodynePostGain = new Tone.Gain(2.0);
heterodyne.connect(heterodynePostGain);
// Create the rectifier node
var rectifier = new Tone.WaveShaper([1, 0, 1]);
heterodynePostGain.connect(rectifier);
// Create the lowpass filter to mask off the difference (near zero)
var lpFilter = new Tone.Filter(5, 'lowpass');
lpFilter.Q.value = 1; // don't need a peak
rectifier.connect(lpFilter);
var lpFilterPostGain = new Tone.Gain();
lpFilter.connect(lpFilterPostGain);
var waveshaper = new Tone.WaveShaper([1, 0, 1]);
lpFilterPostGain.connect(waveshaper);
// create a lowpass filtered follower to turn the bandpass filter output into a smooth control
// signal for the carrier filter
var follower = new Tone.Follower(0,0);
modulatorFilterPostGain.connect(follower);
var followerLowPass = new Tone.Filter(50, 'lowpass');
follower.connect(followerLowPass);
// Create the bandpass filter in the carrier chain
var carrierFilter = new Tone.Filter(this.vocoderBands[i].frequency, 'bandpass', -24);
@ -134,9 +118,10 @@ Vocoder.prototype.initBandpassFilters = function () {
carrierFilter.connect(carrierFilterPostGain);
// Create the carrier band gain node
var bandGain = new Tone.Gain(0); // audio-rate inputs are summed with initial intrinsic value
var bandGain = new Tone.Gain(0);
carrierFilterPostGain.connect(bandGain);
waveshaper.connect(bandGain.gain); // connect the lp controller
followerLowPass.connect(bandGain.gain);
bandGain.connect(this.outputGain);
}