David A. Berkley
James E. West
Acoust. Res. Dept., AT&T Bell Labs., Murray Hill, NJ 07974
Directional microphones are being used increasingly for teleconferencing in a variety of environmental conditions such as varying size and design of the rooms in which they function. However, little is known about the subjective effects of varying environments on the hypothetical improvements produced by these complex microphone systems. It is possible, but quite difficult and expensive, to directly test any proposed microphone system design in a variety of actual or experimental rooms. An alternative approach is use of computer simulation, both of the microphone system and the room environment. A complex microphone system can be modeled as a collection of point microphones distributed in space and summed with appropriate time delays. Established room simulation modeling methods were used. Combining both models together, with appropriate attention to spatial and time resolution of the microphone model, allows calculation of the impulse response of the complete structure, in an arbitrary room environment. The resulting impulse response can be used as a filter for speech. Results of such simulations are presented and compared with real room results.