Visualization and Evaluation of Reflections inside an Enclosed Space Using Sound Intensity Measurement

Abstract

To examine the relationship between surface scattering and the properties of a sound field, a visualization technique based on the sound intensity measurement is introduced. Measurement of the impulse responses at four closely located points yields the intensity response in three orthogonal directions. Dominant peaks in the intensity response could be recognized as the dominant reflections from the certain room surface. Our method projects such information onto the spherical panoramic photo of the field. In addition to such qualitative visualization, quantitative examination is also tried. We have introduced here the index called uniformity of arrival directions, UAD, as one measure of sound field. The UAD is defined by the temporal changes of uniformity of arriving directions of reflections and is calculated by the intensity levels observed at equally divided solid angles on the surface of an imaginary sphere around the measurement point.