node package manager

tonegenerator

Generates a tone as raw PCM WAV data, so you can do operations on it

ToneGenerator for node.js

This thing generates raw PCM data, specified by a frequency and length in seconds.

tone(frequency, lengthInSeconds, [volumen])
var tone = require("tonegenerator");
var A440 = tone(440, 20, 30); // get PCM data for a 440hz A, 20 seconds, volume 30 

I'm really unsure what the 'volume' value means, but you can use it to create different tones with different volumes, let me know how it works for you!

The data is returned as a normal array, so you can do operations on it. Before writing to a file, you need to convert it to a buffer:

var tone = require("tonegenerator");
var header = require("waveheader"); // https://www.npmjs.org/package/waveheader 
var fs = require("fs");
 
// An A-major chord 
var tone1 = tone(440, 2, 60);
var tone2 = tone(554.37, 2, 30);
var tone3 = tone(659.26, 2, 30);
 
// "playing" one tone at the time 
// note that at this time, our sound is just an array 
// of gain values. By appending the raw PCM data for one after another, 
// we can play them in a sequence 
var res = [].concat(tone1);
res = res.concat(tone2);
res = res.concat(tone3);
 
// By adding values of the tones for each sample, 
// we play them simultaneously, as a chord 
for(var i = 0; i < tone1.length; i++) {
  res.push(tone1[i] + tone2[i] + tone3[i]);
}
 
// write to file (note conversion to buffer!) 
var writer = new fs.createWriteStream("A-major.wav");
writer.write(header( 44100 * 8 )); // 44100 Hz * 8 seconds 
writer.write(new Buffer(res));
writer.end();