Conference microphone with adjustable directivity
James L. Flanagan, Robert A. Kubli · The Journal of the Acoustical Society of America · 1985
A design technique is described in which a line array microphone is provided adjustable spatial directivity suitable to a variety of teleconference applications. The directivity of the system is controlled by acoustic insert elements, selected for the spatial coverage desired. By virtue of a modified end-fire directivity pattern, the array can be located above head level and out of line of sight of the conferees. The design technique utilizes acoustic summation and acoustic low-pass filtering to prevent spatial aliasing. Only a single inexpensive electret element is required for the transducer. A prototype model is fabricated and experimental measurements, made under free-field conditions, are shown to compare satisfactorily with calculated theoretical responses.