| 摘要 |
PROBLEM TO BE SOLVED: To realize a high transduction efficiency by providing a support means that supports a resonance multi-mode radiator element where the ratio of 'bending stiffness' to 'cube of panel mass per unit surface area' is specified in a free state and an electromechanical driving means that excites a multi-mode resonance in response to an electric input in an operating frequency band of the speaker to the speaker. SOLUTION: The panel has at least 10 of the ratio of 'bending stiffness' to 'cube of panel mass per unit surface area' in every direction. An electromechanical exciter 4 pushes a shaft 5 onto a rear side face of a radiator 1 to excite the radiator 1 through a reciprocating motion of the shaft 5 by an electric signal. In order to prevent that the radiator 1 is excited in a symmetrical mode with priority, the electromechanical exciter 4 is placed to a position closer to one corner of the radiator 1. The inertial mass of the electromechanical exciter 4 and the inertial mass of the radiator 1 are matched to ensure efficient inertial coupling between the electromechanical exciter 4 and the radiator 1 for efficient power transmission.
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