Soundrive

A simple but flexible audio oscillator for ECMAScript.

Preface

The need for Soundrive came from wanting an oscillator that can smoothly sweep between frequencies while still being easy to use in Node.js and browsers.

To use in the browser, you will probably have to compile it using Babel and/or a tool like Browserify.

Installation

npm install --save soundrive

Yay! No dependencies!

Use

Simplest example:

const Soundrive  = require('soundrive'),
      oscillator = Soundrive.Oscillator.create({frequency: {value: 12345}}),
      frameSize  = 4096,
      frame      = new Float32Array(frameSize);

let i = 0;

while (i < frameSize) {
  frame[i] = oscillator.process();
  i++;
}

The following creates a sweep(i.e. chirp) between two frequencies:

const oscillator = Soundrive.Oscillator.create({
  frequency: {
    value: 1234,
    ease: 0.5
  }
}),

frameSize = 44100, // one second if that's the sample rate
frame     = new Float32Array(frameSize);

let i = 0;

oscillator.changeFrequency(2345);

while (i < frameSize) {
  frame[i] = oscillator.process();
  i++;
}

The resulting frame of samples will be 1 second with a 0.5 second transition between 1234hz and 2345hz.

Mix

You can "mix" oscillators together to produce multiple tones.

const oscillator1 = Soundrive.Oscillator.create({frequency: {value: 770}}),
      oscillator2 = Soundrive.Oscillator.create({frequency: {value: 852}}),
      frameSize   = 4096,
      frame       = new Float32Array(frameSize),
      mix         = oscillator1.mix(oscillator2);

let i = 0;

while (i < frameSize) {
  frame[i] = mix.process()
  i++;
}

Testing

Tests use Mocha. Use npm run test to perform them.