function generateExpectedBusFromFOAIRBuffer(buffer) {
    var generatedBus = new AudioBus(2, buffer.length, buffer.sampleRate);
    var W = buffer.getChannelData(0);
    var Y = buffer.getChannelData(1);
    var Z = buffer.getChannelData(2);
    var X = buffer.getChannelData(3);
    var L = generatedBus.getChannelData(0);
    var R = generatedBus.getChannelData(1);
    for (var i = 0; i < buffer.length; ++i) {
      L[i] = W[i] + Y[i] + Z[i] + X[i];
      R[i] = W[i] - Y[i] + Z[i] + X[i];
    }
    return generatedBus;
  }
Calculate the expected binaural rendering (based on SH-maxRE algorithm)
result from the impulse input and generate an AudioBus instance.
@param  {AudioBuffer} buffer     FOA SH-maxRE HRIR buffer.
@return {AudioBus}