| 摘要 |
PROBLEM TO BE SOLVED: To reduce an influence of a sound leak on the back side of a flat speaker installed on a ceiling or wall. SOLUTION: The flat speaker includes a dish-like frame 2 having an opening, a flat plate type diaphragm provided in the opening of the frame 2, a driving unit provided in the frame 2 and coupled to the diaphragm to vibrate the diaphragm, and a noise reduction device 3 provided on the opposite side from the diaphragm in a sound output direction, the noise reduction device 3 being configured to output a cancel sound for a sound to be silencing. Thus, the noise reduction device 3 outputs the cancel sound to deaden or reduce a sound which may be offensive to residents of upper-story and adjacent rooms. Consequently, the influence of the sound leak on the back side of the flat speaker 1 can be reduced. COPYRIGHT: (C)2010,JPO&INPIT
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