Perceptual evaluation of Acoustic Level of Detail in Virtual Acoustic Environments

TL;DR

This study investigates how reducing acoustic level of detail in virtual environments affects perceptual realism, speech understanding, and externalization, finding that significant simplifications can be made without perceptual loss.

Contribution

It provides empirical evidence on the minimal acoustic detail needed for realistic virtual acoustic environments, guiding real-time simulation simplifications.

Findings

Strong reduction in ALOD maintains perceptual plausibility.

Number and accuracy of early reflections are less critical.

Diffuse late reverberation representation is essential.

Abstract

Virtual acoustic environments enable the creation and simulation of realistic and eco-logically valid daily-life situations vital for hearing research and audiology. Reverberant indoor environments are particularly important. For real-time applications, room acous-tics simulation requires simplifications, however, the necessary acoustic level of detail (ALOD) remains unclear in order to capture all perceptually relevant effects. This study examines the impact of varying ALOD in simulations of three real environments: a living room with a coupled kitchen, a pub, and an underground station. ALOD was varied by generating different numbers of image sources for early reflections, or by excluding geo-metrical room details specific for each environment. Simulations were perceptually eval-uated using headphones in comparison to binaural room impulse responses measured with a dummy head in the corresponding real environments, or by using loudspeakers. The study assessed the perceived overall difference for a pulse stimulus, a played electric bass and a speech token. Additionally, plausibility, speech intelligibility, and externaliza-tion were evaluated. Results indicate that a strong reduction in ALOD is feasible while maintaining similar plausibility, speech intelligibility, and externalization as with dummy head recordings. The number and accuracy of early reflections appear less relevant, pro-vided diffuse late reverberation is appropriately represented.