The present invention relates generally to variable-directivity microphone devices and more particularly to a variable-directivity microphone device in which at least three unidirective microphone units are combined in a specific arrangement, and the respective output signals of these microphone units are mixed with varied mixing ratios, whereby the directivity is varied widely, and zooming of the acoustic or sound image can be carried out with ample sense of distance change as sensed by the listener.
Heretofore, as a microphone device capable of varying directivity, there has been a microphone device of a constitutional arrangement wherein two unidirective microphones are disposed in opposition, and their outputs are mixed with varied mixing ratio. In this device, a final output signal is obtained by varying the mixing ratio thereby to make possible variation of the directivity of the microphone device, as a resultant effect, from a state of non-directivity, through bidirectivity, up to unidirectivity.
However, in this known microphone device, the range of variation of the directivity is narrow, whereby there is the drawback of insufficient acoustic image zooming effect with ample sense of distance change.