Comparing Online vs. Lab-based Experimental Approaches for the Perceptual Evaluation of Artificial Reverberation

Abstract

A common approach for reproducing room acoustics effects is geometrical acoustics. The accuracy of such an approach is tied, among other variables, to the geometrical accuracy of the simulated room, and to the information regarding the absorption coefficients of its materials. However, from a perceptual standpoint, a model that accounts for all of a room's features would come at a high computational cost and could be redundant. As a result, a compromise can be reached between the perceived quality (e.g. authenticity, immersion, etc.) of the replicated room effect and the model's complexity. The purpose of this study is to look into the perceptual impact of simplifying the room geometry and minimizing the number of materials' absorption coefficients. Two separate experiments were conducted, both based on the MUSHRA methodology: one was run in a controlled lab environment through a Virtual Reality (VR) headset, while the other was run through a web-based interface. This paper focuses on the differences between the two protocols' impact on the results. It appears that the online-based experiment, notwithstanding the lack of control of the playback system and environment, and the participants' likely limited attention, produced minor but substantial differences with the results of the VR experiment.