Perceptually relevant parameters for virtual listening simulation of small room acoustics

Various physical aspects of room-acoustic simulation techniques have been extensively studied and refined, yet the perceptual attributes of the simulations have received relatively little attention. Here a method of evaluating the perceptual similarity between rooms is described and tested using 15 small-room simulations based on binaural room impulse responses (BRIRs) either measured from a real room or estimated using simple geometrical acoustic modeling techniques. Room size and surface absorption properties were varied, along with aspects of the virtual simulation including the use of individualized head-related transfer function (HRTF) measurements for spatial rendering. Although differences between BRIRs were evident in a variety of physical parameters, a multidimensional scaling analysis revealed that when at-the-ear signal levels were held constant, the rooms differed along just two perceptual dimensions: one related to reverberation time (T(60)) and one related to interaural coherence (IACC). Modeled rooms were found to differ from measured rooms in this perceptual space, but the differences were relatively small and should be easily correctable through adjustment of T(60) and IACC in the model outputs. Results further suggest that spatial rendering using individualized HRTFs offers little benefit over nonindividualized HRTF rendering for room simulation applications where source direction is fixed.