Auralization of High-Order Directional Sources from First-Order RIR Measurements

Markus Zaunschirm,Franck Zagala,Franz Zotter

doi:10.3390/app10113747

Abstract

Can auralization of a highly directional source in a room succeed if it employs a room impulse response (RIR) measurement or simulation relying on a first-order directional source, only? This contribution presents model and evaluation of a source-and-receiver-directional Ambisonics RIR capture and processing approach (SRD ARIR) based on a small set of responses from a first-order source to a first-order receiver. To enhance the directional resolution, we extend the Ambisonic spatial decomposition method (ASDM) to upscale the first-order resolution of both source and receiver to higher orders. To evaluate the method, a listening experiment was conducted based on first-order SRD-ARIR measurements, into which the higher-order directivity of icosahedral loudspeaker’s (IKO) was inserted as directional source of well-studied perceptual effects. The results show how the proposed method performs and compares to alternative rendering methods based on measurements taken in the same acoustic environment, e.g., multiple-orientation binaural room impulse responses (MOBRIRs) from the physical IKO to the KU-100 dummy head, or higher-order SRD ARIRs from IKO to em32 Eigenmike. For optimal externalization, our experiments exploit the benefits of virtual reality, using a highly realistic visualization on head-mounted-display, and a user interface to report localization by placing interactive visual objects in the virtual space.

Highlights

A modular and interactive measurement-based auralization of an acoustic environment benefits from a separation into its source-dependent, room-dependent, and receiver-dependent parts.Typically, the room-dependent part is characterized by a point-to-point room impulse response (RIR), which often assumes that source and receiver are both omnidirectional [1]
Why source directivity matters: Otondo and Rindel [2] demonstrated that room acoustics parameters change with source directivity, and results from listening experiments indicate that the resulting loudness, reverberance, and clarity changes induced by directivity are perceived by listeners
As results show little to no variation in height (z coordinate), we focus on an evaluation of the x, y coordinates

Summary

Introduction

A modular and interactive measurement-based auralization of an acoustic environment benefits from a separation into its source-dependent, room-dependent, and receiver-dependent parts.Typically, the room-dependent part is characterized by a point-to-point room impulse response (RIR), which often assumes that source and receiver are both omnidirectional [1]. A modular and interactive measurement-based auralization of an acoustic environment benefits from a separation into its source-dependent, room-dependent, and receiver-dependent parts. Employing variable source and receiver directivities during auralization requires a more flexible room description that facilitates interfacing between the three parts. Why source directivity matters: Otondo and Rindel [2] demonstrated that room acoustics parameters change with source directivity, and results from listening experiments indicate that the resulting loudness, reverberance, and clarity changes induced by directivity are perceived by listeners. Vigeant et al [3] found that including source directivity can increase the realism of auralization results. Latinen et al [4] showed that the source directivity can be used to alter the direct-to-reverberant ratio, which strongly correlates with perceived distance of a source.

Methods

Results

Discussion

Conclusion