An investigation of rooms with reflection-free zones using finite-difference methods in curvilinear coordinates

Abstract

Small-room acoustical designers have applied the concept of early reflection-free zones (RFZs) to recording studio control rooms and other critical listening environments. The rooms' unique shapes and treatments create listening regions with minimal early reflections to improve audio monitoring. One standard tool for studying room acoustics is the finite-difference(FD) method. However, it typically uses regular Cartesian grids, which lead to stair-casing discretization effects for arbitrarily shaped boundaries, including those of the RFZ room. This work presents how FD methods in curvilinear coordinates overcome these difficulties. Both modal and time-domain analyses yield insights into the acoustical differences between RFZ and rectangular shoebox rooms.