Contemporary game engines such as Unreal Engine and Unity are widely used for Extended Reality (XR), yet their native audio pipelines often rely on simplified spatialization with limited acoustic control. In Augmented Reality (AR), virtual sound sources must integrate coherently with the physical environment to maintain perceptual plausibility, making accurate Six-Degrees-of-Freedom (6DoF) rendering critical. This study carried out a perceptual evaluation of multiple 6DoF audio rendering approaches, including Audiokinetic Wwise (Reflect and RoomVerb), Steam Audio, Meta XR Audio SDK, a dense 6DoF Room Impulse Response (RIR) interpolation method, and APLVirtuoso XR. A measured physical room was reconstructed in Unreal Engine 5, and the rendering pipelines were calibrated by matching the reverberation time (RT60) and direct-to-reverberant ratio (DRR) to the measured room within their respective just noticeable difference (JND) thresholds. The results showed significant differences in perceived spatial and timbral fidelity as well as plausibility and overall listening experience across the tested renderers. Despite the high accuracy achieved by the 6DoF interpolation method, an algorithmic renderer demonstrated comparable or superior performance. However, some other algorithmic renderers exhibited tradeoffs in terms of computational overhead and acoustic modelling accuracy. Our findings indicate that an optimised system prioritising a plausible auditory representation, rather than strict physical replication, may be sufficient and, in some cases, can yield superior perceptual outcomes.
Holographic calling systems aim to create the perceptual illusion that a remote interlocutor is physically present by combining augmented reality (AR) visualizations with spatial audio rendering. A key cIRCAM:Galleryenge in such systems is achieving audiovisual coherence when room-acoustic properties must be inferred, since this can lead to greater inaccuracies than when they are estimated from measurements. In this study, we investigate perceptual tolerance to mismatches in the direct-to-reverberant energy ratio (DRR), a critical cue for auditory distance perception. We conducted a listening experiment in which participants judged whether the audio and the visual presentation of a stimulus were coherent using a yes/no task. Stimuli included both a volumetric capture of a speaking human avatar, rendered at the correct direct sound level, and a loudspeaker reproducing wideband noise. For the loudspeaker, level roving was introduced to assess the influence of intensity cues on listener decisions. Results show that audiovisual coherence is maintained for half of the presentations within a DRR mismatch range of approximately 3 dB for too dry and 4.3 dB for too reverberant renderings. Within the limited number of participants included in the study, no evidence for significant differences was found between speaking avatars and loudspeakers reproducing noise, nor between different ranges of level roving in the loudspeaker condition. Nevertheless, the findings help to understand the consequences of DRR estimation mismatches for holographic AR calling experiences.
In building acoustics, modeling and auralizing sound transmission through walls is a relevant area of research related to residential well-being and workplace productivity. While most existing studies use auralization methods that focus on accurately reproducing spectrum and amplitude of the sound transmission in accordance with ISO standards, almost no studies have explicitly tried to evaluate the perceptual quality of wall transmission auralization. To address this, the present study applies the plausibility paradigm to evaluate a measurement-based auralization approach to validate it for further psychoacoustic experiments on residential well-being. Binaural Room Impulse Responses (BRIRs) were measured for three loudspeakers placed in adjacent rooms to a central listening room. In a subsequent listening test, participants were asked to evaluate the overall plausibility of the auralization. Results demonstrate that due to the absence of visual cues, the lower sound pressure level, the reduced signal-to-noise ratio, and the diffuse radiation characteristic of the source, high plausibility scores close to the guessing rate were achieved for all adjacent rooms. These findings suggest that due to the lack of a visual cue, lower sound pressure level, reduced signal to noise ratio and the diffuse radiation characteristics of the source, auralization of wall transmission using BRIRs can be used as a plausible method for psychoacoustic research on residential well-being, without the need for complex physical simulations.
