code: function convertToMono(input) {
      var splitter = audioContext.createChannelSplitter(2);
      var merger = audioContext.createChannelMerger(2);
  
      input.connect(splitter);
      splitter.connect(merger, 0, 0);
      splitter.connect(merger, 0, 1);
      return merger;
  }
docs: gotStream