Higher-Order Spatial Impulse Response Rendering: Investigating the Perceived Effects of Spherical Order, Dedicated Diffuse Rendering, and Frequency Resolution

This article details an investigation into the perceptual effects of different rendering strategies when synthesizing loudspeaker array room impulse responses (RIRs) using microphone array RIRs in a parametric fashion. The aim of this rendering task is to faithfully reproduce the spatial characteristics of a captured space, encoded within the input microphone array RIR (or the spherical harmonic RIR derived from it), over a loudspeaker array. For this study, a higherorder formulation of the Spatial Impulse Response Rendering (SIRR) method is introduced and subsequently employed to investigate the perceptual effects of the following rendering configurations: the spherical harmonic input order, frequency resolution, and utilizing dedicated diffuse stream rendering. Formal listening tests were conducted using a 64-channel loudspeaker array in an anechoic chamber, where simulated reference scenarios were compared against the outputs of different methods and rendering configurations. The test results indicate that dedicated diffuse stream rendering and higher analysis orders both yield noticeable perceptual improvements, particularly when employing problematic transient stimuli as input. Additionally, it was found that the frequency resolution employed during rendering has only a minor influence over the perceived accuracy of the reproduction in comparison to the other two tested attributes.