Detection of events by means of plane wave decomposition analysis and cross-correlation technniques using a circular array of microphones

Abstract

This article deals with the study and analysis of room acoustics through a process of sound field decomposition sampled with microphones circular arrays. The spatial characteristics of the sound field inside a room can be meaningfully described by means of microphone array processing techniques. In this context, the set of impulse responses sampled by a microphone array can be seen as an image made of acoustic plane wave footprints. Due to the circular geometry of the microphone array, these footprints have a cosine-like shape that can be fully described as a function of the direction of arrival (DOA) of the impinging plane wave. Plane-wave decomposition (PWD) technique using microphone arrays have been shown to be a very useful tool within the applied acoustics community for their multiple applications in room acoustics analysis and synthesis. This paper conducts an analysis methodology based on the above method to analyze the sound field inside a selected set of real rooms having a well-defined purpose. Through the development of a cardioid microphones circular array as well as the implementation of a wave detection algorithm in echograms based on a cross-correlation method, the acoustics of a room (reflections, absorptions, etc.) is obtained, analyzed and compared following to extrapolate some conclusions about its features, performance and quality.