| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic conversion device for active noise control which utilizes a space inside of any suitable structure of a vehicle as a capacitor and prevents water or any foreign substance from the structure from reaching a diaphragm or the like in a speaker unit.SOLUTION: A first connection part 41 is positioned higher than a second connection part 42, and a duct body 40 is tilted. Therefore, e.g., even if the vehicle is traveled in the rain and water or any foreign substance enters a structure ST, water or the foreign substance is unlikely to enter an enclosure 3 along a duct 4 and water or the foreign substance can be prevented from reaching a member (such as a diaphragm 21, an edge or a damper) constituting a speaker unit 2. Namely, a bottom resonant frequency is prevented from being varied by depositing water or any foreign substance onto a vibrating portion in the speaker unit 2, sound emitted by an acoustic conversion device 1 for active noise control is made unlikely to be deviated from an inverse phase of noise that should be suppressed or cancelled, and noise can be effectively suppressed or cancelled.SELECTED DRAWING: Figure 3 |
