A Generic Reverberation Characterization Metric for Accurate Simulation in Virtual and Augmented Reality Environments

Reverberation is one of the key audio effects for producing highly immersive experiences in virtual acoustic environments (VAEs). Yet, traditional architectural acoustic metrics are not always suitable for characterizing reverberation for such environments. Metrics such as the Direct-to-Reverberant ratio and critical distance are well known to acousticians and sound engineers, but their relation to the excitation of the room is achieved through the direct path energy of the sound from a source to a receiver. That implies that these metrics are heavily dependent on the receiver’s position relative to the source. This dependency is specifically problematic when the user and/or sound sources can move freely throughout the VAE, such as during rendering for VR and AR. After all, given an excitation of the environment, the reverberation level, by definition, is consistent across the environment and independent of the user’s position. A generic metric for reverberation level must therefore relate it to the excitation of the room. To characterize a VAE in a generic way, a new metric is required that characterizes a reverberation level in relation to the excitation, yet independent of the source and receiver positions. The Diffuse to Source Ratio (DSR) metric is introduced that was developed in the context of MPEG-I immersive audio, an upcoming audio standard for efficient transmission and storage of 6DoF audio. It links the reverberation energy to the total radiated sound source energy.