Introduction

In the past, acousticians have used a wide range of design techniques to provide good room acoustics, but acoustical options or the final result could not be tested prior to construction, except by evaluating scale models. Despite these limitations, acousticians have produced some remarkable performance and critical listening rooms. Wouldn't it be nice if we could listen to a room before it is built? In this way we might be able to avoid some of the acoustical problems and evaluate several design options and surface treatments. This process of acoustical rendering, analogous to visual rendering used by architects, has been called auralization. By way of definition, auralization is the process of rendering audible, by physical or mathematical modeling, the sound field of a source in a space, in such a way as to simulate the binaural listening experience at a given position in the modeled space.1 ^,2 Today, advances in computer processing power and digital signal processors are providing acousticians with new tools to predict and simulate the performance of critical listening rooms.

In the broadest of terms, to characterize a room it would be necessary to find a way to follow and catalog the reflection path history of the complex sound reflections as they proceed time through the room. This reflection path history of sound level versus time as picked up at a location in the room can be called an echogram, and the process may be called "ray tracing." In this approach we would follow...