| 摘要 |
PURPOSE:To enable the reproduction of a heavy low-frequency sound even when the musical instrument is reduced in size by providing a driving means which drives a vibrator so as to cancel operation from a resonator side to a vibrating body. CONSTITUTION:When a sound generating device 2 is put in operation, a sound generating circuit 7 converts the vibration of the device 2 into an electric signal. A vibrator driving circuit 8 drives the vibrator 4 according to the electric signal. When a driving signal is supplied from the circuit 8 to the vibrator 4, a diaphragm 3 is driven forward and backward reciprocally. Here, the rear surface side of the diaphragm 3 forms a resonance driving part for driving the Helmholtz's resonator consisting of a sealed box 5 and a duct 6. Atmospheric reaction to the operation of the diaphragm is applied to the rear surface side of the diaphragm 3 from the air in the sealed box 5, but the circuit 8 drives the diaphragm 4 so as to cancel the atmospheric reaction. Consequently, the frequency characteristics of a direct radiant sound is not affected by the capacity of the sealed box 5. Therefore, even if the sealed box 5 is reduced in size, reproduction up to a low frequency sound is possible and the musical instrument is reducible in size. |
