| 摘要 |
PURPOSE:To prevent undesired open tube resonance sound at driving and to reduce noise or radiation sound distortion by providing a 2nd Helmholtz resonance tube resonated to the open tube resonance frequency and providing a servo part to a diaphragm driver. CONSTITUTION:An open tube port 12 of a Helmholtz resonator 10 has an open tube port 18 and a cavity 17 and a 2nd helmholtz resonator 15 is provided opened to the center of the port 12 by the open port 18 of the port 16. Moreover, a vibrator 20 comprising a diaphragm 21 and a transducer 22 is fitted to the resonator 10 and the transducer 22 is connected to the diaphragm driver 30. The driver 30 is provided with a servo part 31 applying electric servo so as to cancel air reaction from the resonator side at the drive of the resonator 10. Thus, since the volume of the cavity of the resonator 10 is reduced more than that of the bass reflex speaker system, up to a low sound is reproduced even with miniaturization and the undesired open tube resonance sound caused at the drive of the resonator 10 is prevented by the provision of the resonator 16 thereby reducing noise or radiation sound distortion. |
