On Immersivity of Transmitted Spatial Sounds for Human-Machine Interaction

Spatial sound perception is a natural way of perceiving sound (not only) by humans and serves for spatial orientation, escape from imminent danger, or shifting attention toward an object of interest. In the modern world, spatial sound, transmitted e.g. via telecommunications networks, is increasingly used to convey an additional dimension of information to the recipient (e.g. an air traffic controller can virtually hear a pilot from the direction where his aircraft is located, etc.). Given the expanding field of AI for generating spatial information, it is necessary to investigate the influence of basic technical parameters on the subjective experience of the recipient, represented, for example, by the immersiveness of communication, the intelligibility of transmitted speech spatial mix, or the spatial resolution of multiple sound stimuli. When using AI to generate spatial sound, the influence of (computational) delay on the quality of the subjective experience is crucial (the recipient's head movement is tracked using head-tracker embedded in the headphones, and the audio channels information is rendered in real time to compensate for any head movements of the subject, so that the sound appears to come from a fixed location regardless of the head's orientation). Any delay in this computational loop can compromise the subjective perception or quality of communication.The paper will present the results of extensive subjective tests that clarify the relationship between (computational) delay and the quality of subjective perception in various tested situations. The results can be directly used to specify the minimum technical requirements for design of AI-based audio-immersive communication and control systems.