| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To increase the degree of freedom of design by adjusting the natural resonance frequency of a resonance chamber with the opening area or opening depth of an opening provided on an opposite side of a soundboard. <P>SOLUTION: Each resonance chamber RM of the resonance box of a sound source unit UNT is provided with an opening 61 which is open opposite a corresponding soundboard 30. At an intermediate-pitch part 50, a through hole 91 which is open on the opposite side of the corresponding soundboard 30 is formed connecting with a corresponding to resonance chamber RM2, and although a resonance chamber RM2-1 and a resonance chamber RM2-2 have the same capacity, the resonance chamber RM2-2 has a higher resonance frequency since a through hole 91A2 corresponding to the resonance chamber RM2-2 has larger opening area than a through hole 91A corresponding to the resonance chamber RM2-1. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
