US Patent 7391879 Loudspeaker

An inventive loudspeaker includes a diaphragm, a first excitation means for generating structure-borne sound in the diaphragm, and a second excitation means, different from the first one, for setting the diaphragm into a longitudinal vibrational motion in a direction perpendicular to the extension of the diaphragm. In accordance with the invention, the problem of insufficient bass reproduction and/or of the magnitude conflicting with invisible integration or installation is solved in that a second exciter system is introduced, which uniformly moves the diaphragm, or the plate serving as the diaphragm, forward and backward in addition to the bending waves of the structure-borne sound. The sound reproduction therefore is possible across the entire audio-frequency range without impeding the goal of invisible integration or installation.