/** Computes the RMS volume of a group of signal sizes ranging from -1 to 1. */
static double audio_rmsVolume(float[] raw) {
  if (empty(raw)) ret 0;
  double sum = 0;
  for (int ii=0; ii<raw.length; ii++)
    sum += raw[ii];
  double average = sum/raw.length;

  double sumMeanSquare = 0d;
  for (int ii=0; ii<raw.length; ii++)
    sumMeanSquare += Math.pow(raw[ii]-average, 2d);
    
  double averageMeanSquare = sumMeanSquare/raw.length;
  double rootMeanSquare = Math.sqrt(averageMeanSquare);

  return rootMeanSquare;
}