| Résumé |
Notions of presence and space are intermingled. Therefore, even if vision is known to provide accurate space perception because of its resolution, audition should give rise to a better sense of presence because of its continuous access to the whole 3D environment. Spatial organisation of an auditory scene is built upon different acoustical cues such as source localisation, source directivity and room effect. When these cues are provided and interaction is allowed, high levels of presence can be easily reached. We conducted several experiments in which different techniques of 3D audio were used. In one case, wave field synthesis (WFS) was used in a situation of mixed reality, to assess distance perception. In another case, binaural techniques were incorporated to a visual VR setup. In the last case, binaural techniques were used in a wireless auditory VR setup. Thanks to the properties of WFS, allowing the reproduction of a sound field in an extended listening area, source localisation could be accurately evaluated by subjects through dynamic exploration of the soundscape. In the second case, subjects were submitted to a navigation task and did perform better when 3D audition was added. In the last case, despite the absence of visual stimulation, subjects managed to build an accurate cognitive representation of an auditory virtual environment. Subjects performances in these experiments were taken as an index of presence together with behavioural reactions to the VE, debriefing with the subjects, and presence questionnaire scores. From these different experiments, we propose that the following elements do contribute to the sense of presence in an auditory virtual environment (VE): intra-congruency of the VE, whatever the properties of the VE – artificial or realistic, quality of the scenario (VE), number of factors giving information on the elements constituting the VE (room effect, directivity),… Different acoustical cues can be used to provide a better sense of space, while such diversity does not exist in the visual domain. For this reason and because of the absence of restriction in the addressed receptive field, audition shows primacy among sensory modalities to promote presence in VR. |
