| 摘要 |
Sound waves (SWa) among sound waves (SW) are received by microphones (111, 112) at a predetermined phase difference. On the other hand, sound waves (SWb) pass through a net-formed casing (110), and reach a front surface (210) of a diffuse reflection member (200). Since the front surface 210 is formed to have a random rough surface, the sound waves (SWb) are diffused (diffusely reflected) at the front surface (210). Therefore, reflected sound waves (SWc) from the front surface (210) do not reach the microphones (111, 112) at a proper phase difference. Even if reached, the reflected sound waves (SWc) are received at a phase difference that is different from the phase difference of the sound waves (SWa) by the microphones (111, 112), and are determined as noise by a sound-source determining circuit (123). Therefore, a sound receiver (101) can receive only the sound waves (SWa) having a proper phase difference, and directivity thereof can be improved.
|
