Perception and prediction of apparent source width and listener envelopment in binaural spherical microphone array auralizations.

This article deals with the assessment and prediction of the reproduction quality when binaurally auralizing spherical microphone array data for room simulation applications. The auralization is perceptually assessed in a listening experiment using the two attributes, apparent source width (ASW) and listener envelopment (LEV), for spatial quality description, whereas the technical analysis employs a psychoacoustically motivated model for room acoustical perception (RAP) which is specifically designed to estimate ASW and LEV. Both analyses focus on the array configuration in terms of varying modal resolutions and its influence on the spatial reproduction quality. The auralizations comprise three simulated environments, i.e., free-field sound fields as well as a dry and a reverberant room. Ten different audio signals are used as test material. Perceptual results show that the array configuration strongly influences the perception of ASW and LEV which also depends on the reflection properties of the simulated room. The ASW and LEV predictions by the RAP model correlate well with the results from the listening experiment.

Just noticeable differences of spatial cues in echoic and anechoic acoustical environments.

The perceptual limits for detecting changes in binaural cues also define the boundaries for the perception of differences in spatial impression. This study reports just noticeable differences for interaural time delays (ITDs) and interaural level differences (ILDs) of the early part and for the interaural cross-correlation (IACC) of the early and diffuse part of binaural room impulse responses. The results show that ITDs only allow a high accuracy in localization in anechoic environments, whereas ILDs show a higher robustness against reverberation. Subjects are rather insensitive to changes in IACC, only changes that bring the IACC close to one are detectable.