| 摘要 |
PURPOSE:To realize sufficient acoustic radiating capacity and to miniaturize the title device by using a dynamic type electroacoustic transducer, in which a voice coil is formed with a superconductor, as the transducer of a helmholtz resonator. CONSTITUTION:A resonant acoustic is to be radiated from a helmholtz resonator 10 by providing a dynamic type electroacoustic transducer 20, in which the voice coil is formed with the superconductor, on the Helmholtz resonator 10 and driving the dynamic type electroacoustic transducer 20. Since the voice coil of the dynamic type electroacoustic transducer 20 is formed with the super conductor, the electric resistance of the voice coil is 0, and when the dynamic type electroacoustic transducer 20 is driven by an amplifier 30, in which output impedance is substantially 0, the dynamic type electroacoustic transducer 20 operates only correspondingly to an electric driving signal. Consequently, since Q value is never lowered by the transducer, the Q value of resonance can be maintained as a sufficiently high value even when the acoustic resistance of the resonator becomes large by making the size of the cavity of the resonator smaller and lowering a resonance frequency. Thus, the acoustic radiating capac ity sufficient for the resonator can be secured. |
