Phased-array sound pickup apparatus having no unwanted response pattern

A phased-array sound pickup apparatus comprising:

• an array of microphones having a first subarray of microphones and a second subarray of microphones, the microphones of said first subarray having individual unidirectional response patterns oriented on one side of the normal to said array and the microphones of said second subarray having individual unidirectional response patterns oriented on the other side of said normal;
• a plurality of switches each having first and second switched positions;
• a tapped variable delay line having a plurality of successively connected variable delay circuits with taps between successive ones of said delay circuits, said taps being coupled respectively through said switches in the first switched position to the microphones of said first subarray such that the signal from the microphone located at one end of the first subarray opposite to the orientation of said first subarray microphones is given a maximum delay, said taps being further coupled respectively through said switches in said second switched position to the microphones of said second subarray such that the signal from the microphone located on an end of the second subarray opposite to the orientation of the second subarray microphones is given a maximum delay, whereby incremental variable delays are introduced to the signals from said microphones so that the array has a main front lobe oriented on one side of the normal to said array when the switches are transferred to the first terminals and said main front lobe is oriented on the other side of said normal when said switches are transferred to the second terminals, the delayed signals being combined at an output terminal in a phased relationship dependent on the amount of delay introduced by each of said delay circuits;
• and
• a delay control circuit for controlling said variable delay circuits and said switches in response to a manually adjustable setting.