| 摘要 |
Loudspeaker boxes (cabinets) are generally designed for direct emission and their electroacoustic data are thus determined when the box is standing on its own. It is known for multi-path boxes to be equipped with switches and/or regulators, by means of which the filters are electrically varied in order thus to be able to carry out acoustic matching or matching to taste. However, there are two special cases of interference of the optimum sound impression. These are: if a box which is designed for free-standing, direct emission, that is to say with a vertical sound wall, is intended to be operated lying on its back for any reason, then this indirect emission leads to an unsatisfactory sound impression. Secondly: if such a box is fitted to a room wall then it generally has an unsatisfactory tendency to hum. The object was to solve both these problems. A push button on the rear wall of the box is necessarily pushed in in the problematic mode of operation and produces a switching changeover in the filter branches of the medium-level tone control in order to solve the first problem, as a result of which its frequency response, level and polarity can be changed. In the case of the second problem, a low-frequency filter can be switched on and over in the filter branch for the low-frequency tone control. The positively automatic changeover for a change in the emission characteristic is, however, possible for a box only either for the "resting on its back" operating mode or "hanging on the room wall", as in the description ... Original abstract incomplete. <IMAGE>
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