Comparison of room‐acoustical parameters predicted using different surface‐reaction models.

Abstract

This paper presents the development of a beam‐tracing model for calculating the transient responses of rooms. The model is wave‐based (i.e., includes phase changes due to distance traveled and wall reflections), and can be applied to rooms with extended‐reaction surfaces. Room surfaces can be modeled as multiple layers of solid, fluid, and poroelastic materials; their acoustical properties are calculated using a transfer‐matrix approach. The beam‐tracing model calculates the complex transfer function of a room. Pressure impulse responses are then computed via Fourier transformation, and the room‐acoustical parameters derived. Since pressure impulse responses are calculated, the model can also be used for auralization. The model has been applied to different room configurations in order to study the effects of different surface‐reaction models on the predicted steady‐state characteristics and temporal variations of sound‐pressure fields in various room configurations. In particular, the audibility of using different boundary conditions (local versus extended reaction, wave‐based versus energy based modeling, and phase changes on reflection) on the room‐acoustical parameters has been investigated: In each configuration, room parameters have been calculated using different boundary conditions, and audible variations of the parameters have been studied and explained.