Binaural Coherence in Rooms

In a study of the binaural properties of rooms, binaural cross-correlation (CC) functions were measured in 19 one-third-octave bands, and broad band, using an artificial head and torso (KEMAR). For a fixed source-receiver distance, twenty CC functions were collected as the source and receiver were moved to different locations in the room. The peaks of the CC functions were taken as measures of binaural coherence. Plots were made of binaural coherence as a function of frequency for five rooms and several source-receiver distances (3 m, 6 m, and 12 m). Attempts were made to interpret the coherence plots in terms of geometrical, material, and acoustical properties of the different rooms in order to develop some intuition about the statistical behavior of the coherence function in rooms. Correctly interpreted, in coordination with headphone lateralization studies, the measured values of binaural coherence are expected to indicate the utility of the steady-state interaural time difference cue in sound localization.