Basic Considerations for Loudness-Based Analysis of Room Impulse Responses

Room impulse responses (RIRs) are used to characterise the acoustical conditions inside sound-critical rooms such as auditoria. The analysis of RIRs typically involves octave-band filtering, with parameters such as reverberation time, early decay time, temporal energy ratios and spatial parameters derived from this. This paper explores the potential for applying auditory models for the analysis of RIRs – incorporating auditory temporal integration (and masking), auditory filterbank analysis, and loudness calculation. The purpose of this is to produce analysis results that are closely related to the sound experienced by listeners. A preliminary step for such analysis is to filter RIRs so that their power spectrum is similar to that of typical material that would be listened to in the rooms (e.g. music or speech), and this paper proposes a music filter suitable for orchestral music, derived from long term power spectra of anechoic music recordings. Dynamic loudness analysis of RIRs yields loudness decay functions that are approximately exponential, which should provide a useful analogy with conventional analysis methods applied to RIRs.