| 摘要 |
PURPOSE:To unnecessitate an earphone and a headphone and to transmit sounds only to a specified person in a specified area. CONSTITUTION:Plural speakers L1-L5 and R1-R5 are serially arranged, the voltages of input signals la to the speakers L1 and R1 at the central part of a bed 3 are made maximum by power amplifiers AMP1-AMP5 for amplification, and the voltages of input signals 1b-1e are more reduced toward the speakers R2-R5 and L2-L5 from the central part to the right and left directions. Thus, the sounds at sound pressure levels high at the central part of the bed 3 and low at the edge parts can be obtained. |
