code: function(input_filename, cb_read_file_done) {
  
      // ------------ read wav file -------------------- //
  
      // console.log("read_wav_file with input_filename ", input_filename);
  
      // bbb
  
      var wav_file_input_obj = {};  // create stub object to which we attach .buffer
  
      var property_buffer_raw_input_file = "buffer_raw_input_file";
  
      wav_file_input_obj.filename = input_filename;
  
      wav_file_input_obj[property_buffer_raw_input_file] = new Buffer(0);
  
      // console.log("abouttttt to read wav_file_input_obj.filename ", wav_file_input_obj.filename);
  
      var spec = {};
  
      read_16_bit_wav_file_into_32_bit_float_buffer(
                                      wav_file_input_obj,
                                      wav_file_input_obj.filename, 
                                      spec,
                                      cb_read_file_done);
  }
docs: read_16_bit_wav_file_into_32_bit_float_buffer NOT for export --- internal consumption ONLY its outer wrapper is called read_wav_file ---