Factors differentiating the 22.2- and 2-channel reproduced sound fields through an acoustic modeling of three listening rooms

Abstract

We have simulated two loudspeaker configurations (22.2- and 2-channel reproduction) using the CATT-Acoustic software and analyzed the influence of room acoustics on the perception of multichannel-reproduced music. With the rapid growth of virtual reality (VR) and mixed reality (AR), there is a need for an immersive acoustic system that can maintain compatibility of auditory impressions in various acoustic conditions. The research question of the authors’ project is whether an increased number of reproduction channels would reduce the room-induced perceptual difference. To answer this question, we have analyzed physical characteristics from calculated impulse responses (IRs) of three distinct room models (varying dimensions and reflecting surfaces). Among many characteristics, the early decay time (EDT) and clarity (C80) values covary with the loudspeaker configurations. The IRs calculated from a 22.2-channel reproduction system had different EDT and C80 values for all three rooms. The change was more evident in a reverberant room (a normal listening room) than a relatively dry room (such as studio control room), possibly due to boosts of the ratio of direct sound to late reflections. No salient factor associated with room differences was observed. The subsequent subjective evaluations, performed by eleven listeners, support that they weighted the perceptual difference associated with the reproduction format more over all other perceptual dimensions.