| 摘要 |
PURPOSE:To lower a peak in a sound pressure versus frequency characteristic in constituting a 2-way speaker system together with a woofer by providing a resonator to at least any position in a space constituted with a front position of a diaphram, a cabinet and the diaphragm so as to decrease the sound pressure due to primary resonance. CONSTITUTION:The middle part of the diaphragm 5 is bonded to a piezoelectric element 2 and an outer circumference part is bonded to a step 1-2 of the inner face of the circumferential durm of the cabinet 1. Moreover, a horn 6 in common use with a retainer is fixed to an opening of the cabinet 1 and retains the outer circumference of the diaphragm 5. The resonator formed by making a hole 7-1 to a cavity 7 surrounded by rigid walls is changed for the resonance frequency freely depending on the inner volume V of the cavity 7, the cross section area S and the length and the frequency is set to an identical frequency as the primary resonance frequency fr1 of a piezoelectric speaker. In the reflection of the sound from the diaphragm 5, the sound pressure of the primary resonance frequency is absorbed by the resonator and the sound pressure of the primary resonance is lowered. |
