| 摘要 |
PURPOSE:To obtain a directivity pattern in which the level of a masking sound is high at the outside of an object service area by synthesizing a main electric signal and a masking electric signal in phase, giving the synthesized signal to speaker units at both ends, synthesizing them in an opposite phase and giving the synthesized signal to a central speaker unit. CONSTITUTION:A signal processing means 200 receives a main electric signal AE corresponding to a main sound AS and a masking electric signal BE corresponding to a masking sound BS to suppress the main sound AS and gives a synthesis electric signal (AE+BE) resulting from the synthesis of the signals AE and BE in phase to speaker units 201, 203 at both ends. Furthermore, a synthesis electric signal (AE+BE) resulting from the synthesis of the signals AE and B while the phase of the signal BE is inverted is given to a central speaker unit 202. Thus, the directivity pattern in which the level of the masking sound is low in an object service area and a level of the masking sound is high at the outside of the service area is provided while the masking sound is simultaneously outputted from one speaker unit. |
