Computer-steered microphone arrays for sound transduction in large rooms
James L. Flanagan, James David Johnston, Rolf Zahn, Gary W. Elko · The Journal of the Acoustical Society of America · 1985
The quality of sound pickup in large rooms—such as auditoria, conference rooms, or classrooms—is impaired by reverberation and interfering noise sources. These degradations can be minimized by a transducer system that discriminates against sound arrivals from all directions except for that of the desired source. A two-dimensional array of microphones can be electronically beam steered to accomplish this directivity. This report gives the theory, design, and implementation of a microprocessor system for automatically steering a two-dimensional microphone array. The signal-seeking transducer system is implemented as a dual-beam, “track-while-scan” array. It utilizes signal properties to distinguish between desired speech sources and interfering noise. The complete automatic system has been tested in anechoic and medium-sized auditorium environments, and its performance is discussed.