The effect of microphone directivity patterns on spatial cues for reverberant multichannel meeting speech analysis

Multiparty meetings common to many business environments often have participants who are generally stationary. Hence, active speakers can be disambiguated by location, and meeting analysis research groups have proposed the use of speaker location information (spatial cues) for meeting segmentation and higher level analysis. As the cues are estimated from multi-microphone recordings, this paper studies the effect of varying microphone directivity patterns on the spatial cue accuracy and reliability. Results from theoretical simulations and recordings from a real reverberant environment suggest that different spatial cues (based on inter-microphone signal time delays or amplitude level differences) optimally respond to different microphone directivity patterns, where time delay accuracy was found to be independent of the relative microphone configuration.