The Influence of Room-Adapted Spatial Audio Rendering on a Holographic Calling Experience

Augmented reality (AR) telemeetings, also referred to as holographic calls, promise a stronger sense of presence and a more natural experience than regular video calls. Using point-cloud transmission and see-through AR displays, visual rendering aims to create the impression that a remote interlocutor is present in the user's room. Room-adapted, dynamic spatial audio rendering should provide the corresponding auditory impression. However, it is still unclear whether room-adapted spatial audio enhances perceived quality and social presence in AR telemeetings, and how its effectiveness is influenced by practical constraints, such as suboptimal room-acoustic match, increased audio capture distance, and lossy audio compression. In our experiment, pairs of participants engaged in conversations on pre-defined topics using an asymmetric AR holographic calling system. All participants experienced both roles in the system: one using a conventional video calling interface and the other viewing a holographic representation of the remote interlocutor. In the latter role, participants experienced eight spatial audio rendering conditions that varied in room-acoustic rendering (no room, matched room, too dry, and too wet), audio capture distance (close vs. far), and audio compression (lossless vs. low bitrate). After each condition, participants completed an eight-item questionnaire, rating audiovisual coherence, audio quality, overall experience, and social presence. The results show that room-adapted spatial audio can significantly enhance overall quality and social presence in AR telemeetings compared to no room acoustic rendering. Surprisingly, we also found improved experiences with relatively large mismatches between rendered and physical room reverberation. Furthermore, increasing capture distance or applying lossy audio compression degraded the experience and eliminated the benefits of room acoustic rendering. These findings provide design guidelines for spatial audio rendering in future AR telemeeting systems: to maximize presence, room-acoustic rendering should be added to high-quality audio from close microphone or dereverberated far microphone capture, even when moderate room acoustic mismatches are expected.