Correlation analysis of room impulse responses for use in musical signal processing

Many important features of musical signals can be extracted from the auto- and cross-correlation functions of a recorded sound. In particular, both binaural localization and pitch estimation rely heavily on the locations of peaks in these correlation functions. However, in reverberant environments, these correlations depend on the respective autocorrelation functions of both the source and acoustic filter. Since the source signal’s autocorrelation is often better understood or more easily estimated than that of the room, modelling the effects of room acoustics on these parameter estimates requires a more detailed understanding of room impulse response correlation functions. This work investigates the correlation properties of both monophonic and binaural room impulse responses from multiple databases, spanning a wide range of room sizes and configurations. Specifically, the cross-correlations between impulse responses recorded at different locations in the same room and between channels of binaural impulse responses are analyzed, with emphasis on the contribution of early reflections, low frequency modes, and late reverberation to these correlations. Finally, examples are used to illustrate the impact of these elements on the resulting pitch and localization cues.