| 摘要 |
A portable self-contained amplified and loud speaker system and apparatus is disclosed herein having improved acoustical energy propagation in connection with musical sound distribution by a musician in a marching band or group. The apparatus includes cylindrical housing provided with shoulder and waist straps and a removable back plate shaped to fit the small of the back of the person wearing the housing. An electronic component package is secured within the housing so that a control panel is exposed for volume adjustment, recording tape insertion, start/stop switches and the like. Loudspeakers are angularly fixed to the opposite ends of the housing so as to close the ends thereof and are operably coupled to the components carried in the package for radiating acoustical energy in response to amplification of electrical signals processed by the components in a predetermined propagation pattern. The housing embodies an elongated tone chamber defined between the pair of end loudspeakers and a sound opening with a grill thereover is provided in the housing at the rear thereof which constitutes a third loudspeaker. The pair of end loudspeakers are wired "out-of-phase acoustically" whereby sound is radiated out of the rear speaker on the back stroke of the end speaker cones.
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