Low Frequency Interactive Auralization Based on a Plane Wave Expansion

Abstract

This paper addresses the problem of interactive auralization of enclosures based on a finite superposition of plane waves. For this, room acoustic simulations are performed using the Finite Element (FE) method. From the FE solution, a virtual microphone array is created and an inverse method is implemented to estimate the complex amplitudes of the plane waves. The effects of Tikhonov regularization are also considered in the formulation of the inverse problem, which leads to a more efficient solution in terms of the energy used to reconstruct the acoustic field. Based on this sound field representation, translation and rotation operators are derived enabling the listener to move within the enclosure and listen to the changes in the acoustic field. An implementation of an auralization system based on the proposed methodology is presented. The results suggest that the plane wave expansion is a suitable approach to synthesize sound fields. Its advantage lies in the possibility that it offers to implement several sound reproduction techniques for auralization applications. Furthermore, features such as translation and rotation of the acoustic field make it convenient for interactive acoustic renderings.

Guest Editors’ Note—Special Issue on Spatial Audio

“…Another inverse problem discussed by Gómez, Astley, and Fazi [10], is for the interactive auralization of sound fields in a low-frequency region. They utilized the finite element method to simulate a sound field in a room and then transformed the result using a plane wave expansion technique.…”

Local Time-Domain Spherical Harmonic Spatial Encoding for Wave-Based Acoustic Simulation

“…Spherical array processing [15], [16] was employed for 3D ambisonic encoding in [17] and differential microphone processing [18], [19] was used in [20] to obtain 2D ambisonic signals. An alternative approach is through plane wave decomposition [21], [22]. These approaches [17], [21], [22] rely on pre-computation of encoding filters, implementing a frequency-domain inversion from pressure values to the encoded signals, and applied to grid signals using block-processing frequency-domain techniques.…”

“…An alternative approach is through plane wave decomposition [21], [22]. These approaches [17], [21], [22] rely on pre-computation of encoding filters, implementing a frequency-domain inversion from pressure values to the encoded signals, and applied to grid signals using block-processing frequency-domain techniques.…”