Perceptual thresholds for realistic double-slope decay reverberation in large coupled spaces

Reverberation highly influences sound perception in enclosed spaces. The reverberation time (RT) metric, used to quantify reverberation in single volumes, is inappropriate for coupled spaces characterized by non-exponential double-slope energy decays. Previous research on reverberation perception of double-slope decays has been predominantly based on varying basic impulse response characteristics such as decay times corresponding to reverberation times of individual volumes presented as independent variables. Alternatively, several studies have employed geometrical room acoustic software simulations to generate collections of responses while varying architectural parameters such as coupling area and room volumes. To avoid issues related to geometrical acoustics simulations, such as position dependence and limitations of some software to properly simulate coupled volume behavior, this study examines perception of the variability of reverberation typical of a physical coupled volume system. Employing an established statistical model, the control parameter of coupling area aperture which acoustically connects the volumes serves as the independent variable. Two listening tests were conducted to determine perceptual thresholds using an ABX discrimination task. The range of tested values corresponded to physically realizable variations. Just noticeable differences (JNDs) were derived with an average JND of ≈ 10% variation of the coupling aperture. No significant differences were found between different musical excerpts.