function makeDistortionCurve(amount) {
  var k = typeof amount === 'number' ? amount : 50;
  var numSamples = 44100;
  var curve = new Float32Array(numSamples);
  var deg = Math.PI / 180;
  var i = 0;
  var x;
  for (; i < numSamples; ++i) {
    x = i * 2 / numSamples - 1;
    curve[i] = (3 + k) * x * 20 * deg / (Math.PI + k * Math.abs(x));
  }
  return curve;
}
Stop the recording. Once the recording is stopped,
 the results will be sent to the p5.SoundFile that
 was given on .record(), and if a callback function
 was provided on record, that function will be called.

 @method  stop
 @for p5.SoundRecorder