Directional microphone systems for teleconferencing

Many factors have contributed to historically unrealistic predictions for the growth of audio teleconferencing. Aside from the sociological issues, there exist many acoustic problems that can severely degrade the performance of present technology. A few of these problems are: the effects of reverberation, room noise, feedback, undesired speakers, and echo. At present, the most common solution for some of these problems has been to locate a microphone(s) in close proximity to the desired speaker(s) with gain switching to eliminate feedback problems. While this solution can sometimes be effective, it also introduces some compromises that are easily spotted and are considered annoying by teleconferencing users. The most notable problems are with gain switching and reverberation. These detrimental effects can be reduced by the use of highly directional microphones systems tailored to the problems of teleconferencing. The development of directional microphones and their present use in audio teleconferencing will be reviewed. Some of the highly directional microphone arrays that have been worked with will be described. Finally, comments will be given on how these new directional microphone systems address the problems of teleconferencing in small and large acoustic environments.