Spatial perception and immersion -Auditory perception

The dossier on spatial perception, immersion and virtual reality includes three articles:

• Visual perception of space [TE 5 182];

• Space perception, immersion and virtual reality [TE 5 184];

• Auditory perception of space.

This second article shows how auditory perception of space translates into the listener's ability to perceive sound sources distributed all around him. Unlike the visual field, the auditory field concerns the entire surrounding spatial volume, not just the part in front of it. It is characterized by the ear's ability to transmit information to the brain, enabling it to assess the position of a sound source in terms of width, height and depth. The relative arrangement of the various sources in the auditory field constitutes the sound perspective.

In sound recording, it is customary to speak of "sound image". The term is inappropriate when applied to the auditory environment surrounding the listener, but is fully justified by the fact that the brain naturally extracts information from the front to highlight auditory information that converges with visual information.

Today, no recording system can reproduce the original sound field. The recording of musical works is therefore the result of a compromise between multiple variables that can be classified schematically into two categories: precision variables and environmental variables. The former are analytic and quantifiable, while the latter are the result of a synthesis of spatial variables that can only be assessed subjectively.

Sound immersion has its roots in the first category of variables (analysis of space), but only finds its justification in the second (the sensation of being immersed in the room).