Locating Image Sources from Multiple Spatial Room Impulse Responses

Otto Puomio,Tapio Lokki,Nils Meyer-Kahlen

doi:10.3390/app11062485

Abstract

Measured spatial room impulse responses have been used to compare acoustic spaces. One way to analyze and render such responses is to apply parametric methods, yet those methods have been bound to single measurement locations. This paper introduces a method that locates image sources from spatial room impulse responses measured at multiple source and receiver positions. The method aligns the measurements to a common coordinate frame and groups stable direction-of-arrival estimates to find image source positions. The performance of the method is validated with three case studies—one small room and two concert halls. The studies show that the method is able to locate the most prominent image sources even in complex spaces, providing new insights into available Spatial Room Impulse Response (SRIR) data and a starting point for six degrees of freedom (6DoF) acoustic rendering.

Highlights

Measuring a room impulse response (RIR) with a microphone array makes analyzing sound event directions possible
A Spatial Room Impulse Response (SRIR) can be analyzed in both temporal and spatial domain, which helps us to understand the acoustics of a room better and allows us to reproduce the acoustic behavior of the measured space faithfully
The direct sound estimates are sent to the geometry calibration stage, which uses the data to determine the source-receiver layout

Summary

Introduction

Measuring a room impulse response (RIR) with a microphone array makes analyzing sound event directions possible. Parametric methods for processing SRIR, such as the Spatial Decomposition Method (SDM) [1], Spatial Impulse Response Rendering (SIRR) [2] or Higher-order SIRR (HO-SIRR) [3], have been a cornerstone of concert hall research in recent years [4,5] Such techniques have enabled us to directly compare different spaces in numerous listening tests. Broadband direction estimates are especially well-suited for this, since they allow for interpreting reflections from large walls as image sources with a specific location in space Such visualizations have been used, for example, to better understand the results of perceptual tests [7]

Methods

Discussion

Conclusion