Spatial Audio Processing: MPEG Surround and Other Applications

2.2 Spatial audio playback systems

There has been an ongoing debate about the aesthetic aim of recording and reproducing sound. In recording of classical music or other events implying a natural environment, the goal of recording and reproduction can be to re-create as realistically as possible the illusion of ‘being there’ live. (‘Being there’ refers to the recreation of the sound scene at the place and time of the performance. The term ‘there and then’ is often used to describe the same concept, in contrast to ‘here and now’, which describes the sound scene at the place and time during playback.) In many other cases, such as movie sound tracks and pop music, sound is an entirely artificial creation and so is the corresponding spatial illusion, which is designed by the recording engineer. In such a case, the goal of recording and reproduction can be to create the illusion of the event ‘being here’, i.e. the event being in the room where playback takes place.

In any case, the requirement of a spatial audio playback system is to reproduce sound perceived as realistically as possible, either as ‘being there’ or ‘being here’. Note that in ‘being there’ one would like to create the spatial impression of the concert hall ‘there’, whereas in ‘being here’ the acoustical properties of the playback room ‘here’ are to play a more important role. But these aesthetic issues are to be addressed by the performing artists and recording engineers, given the limits of a specific target spatial ...