Domains of practical applicability for parametric interpolation methods for virtual sound field navigation

Abstract

Suitable domains are established for the practical application of two state-of-the-art parametric interpolation methods for virtual navigation of ambisonics-encoded sound fields. Although several navigational methods have been developed, existing studies rarely include comparisons between methods and, significantly, practical assessments of such methods have been limited. To that end, the errors introduced by both methods are objectively evaluated, in terms of metrics for sound level, spectral coloration, source localization, and diffuseness, through numerical simulations. Various practical domains are subsequently identified, and guidelines are established with which to choose between these methods based on their intended application. Results show that the first method, which entails a time-frequency analysis of the sound field, is preferable for large-area recordings and when spatial localization accuracy is critical, as this method achieves superior localization performance (compared to the second method) with sparsely distributed microphones. However, the second method, which parametrically excludes from the interpolation any microphones that are farther from the listening position than is any source, is shown to be more suitable for applications in which sound quality attributes such as coloration and diffuseness are critical, since this method achieves smaller spectral errors with sparsely distributed microphones and smaller diffuseness errors under all conditions.