A DSP implementation of source location using microphone arrays.

The design, implementation, and performance of a low-cost, real-time DSP system for source location is discussed. The system consists of an eight-element electret microphone array connected to a Signalogic DSP daughterboard hosted by a PC. The system determines the location of a speaker in the audience in an irregularly shaped auditorium. The auditorium presents a nonideal acoustical environment; some of the walls are acoustically treated but there still exist significant reverberation and a large amount of low-frequency noise from fans in the ceiling. The source location algorithm is implemented in a two-step process: The first step determines time delay of arrival (TDOA) for select microphone pairs. A modified version of the cross-power spectrum phase method M. Omologo and P. Svaizer, Proceedings of IEEE ICASSP 1994 (IEEE, New York, 1994), pp. II273–II276 is used to compute TDOAs and is implemented on the DSP daughterboard. The second step uses the computed TDOAs in a least-mean-square gradient descent search algorithm implemented on the PC to compute a location estimate. Work supported by a contract with Bell Communications Research.