Diffuseness and intensity analysis of spatial impulse responses

Abstract

Spatial impulse responses, meaning responses measured with a microphone grid, were measured in seven concert halls. The microphone array consisted of 12 omni-microphones, enabling a construction of three intensity pairs (in x, y, and z directions) with 1 cm spacing and three intensity pairs with 10 cm spacing. In each hall impulse responses were measured with at least three loudspeaker and four microphone positions. They were analyzed with directional audio coding methodology, which enables analysis of diffuseness and instantaneous intensity as a function of time and frequency. In other words, with this analysis it is possible to analyze the directions of early reflections and to estimate diffuseness of sound field in a measurement position. Preliminary results indicate that diffuseness is quite similar in different positions in one hall, but it varies more between halls. The directions of early reflections are hard to visualize, however some example videos are shown to get an idea about the possibilities of such an analysis technique.