| 摘要 |
PURPOSE:To set the horizontal sensitivity at zero and also to secure the narrow directivity in a wide band range. CONSTITUTION:Two unidirective microphones 20 and 22 are set with a space D secured between them so that the coincidence is obtained along the reference axes of both microphones. Then the sound pressure gradient microphones 14, 16 and 18 which obtain the difference of output signals for both microphones 20 and 22 through an adder 24 are arranged with the spaces (d) secured among those three microphones so that their reference axes are set approximately parallel to each other. The output signals of the microphones 14, 16 and 18 are supplied to the equalizers 28, 30 and 32 having the frequency characteristics approximately complementary to the front sensitivity frequency characteristics of the microphones 14, 16 and 18 respectively. Then an adder 34 adds together the output signals of equalizers 28, 30 and 32. |
