18. The method of claim 15 , wherein calculating the respective level difference values includes: dividing a respective time-series representation of each of at least one pair of the respective audible signal data components into a corresponding plurality of buffers; summing respective powers in the corresponding pluralities of buffers; and determining the difference between the respective powers.
15. The method of claim 1 , wherein determining the one or more directional indicator values from the composite audible signal data includes determining one or more first directional indicator values, each of the one or more first directional indicator values is a function of a respective level difference value for each of at least one pair of the respective audible signal data components, each respective level difference value providing an indicator of relative signal powers characterizing the pair of the respective audible signal data components.