Abstract: A diaphragm for a loudspeaker including a plurality of masses, each mass being substantially the same radial distance from the center of the diaphragm, the plurality of masses being divided into two arrays, each array including one or more individual masses, wherein, in use, at a selected frequency, the pair of arrays act to produce a dominant bending moment, and, the center of the diaphragm lies substantially on the axis of the dominant bending moment, wherein, the dominant bending moment is the bending moment produced by the combination of masses which has the greatest magnitude, if they produce more than one bending moment.

Abstract: The present invention provides: a loudspeaker including a frame, a drive unit, and a membrane; the membrane having an inner edge, an outer edge which is suspended from the frame, and a membrane body which is between the inner and outer edges and extends around the drive unit; the drive unit having a stationary part secured to the frame and a translatable part secured to the inner edge of the membrane; the membrane body including a dished portion which, has a depth that increases from said inner and outer edges towards a base region of the dished portion located between said edges; wherein the loudspeaker includes a stiffening element which extends around the drive unit and stiffens the membrane body at the base region of the dished portion, so as to reinforce the membrane against deformation in the base region. By including the stiffening element, it has been found that the first break-up resonance of the membrane is shifted to a higher frequency and has reduced amplitude.

Abstract: A diaphragm for a loudspeaker including a plurality of masses, each mass being substantially the same radial distance from the centre of the diaphragm, the plurality of masses being divided into two arrays, each array including one or more individual masses, wherein, in use, at a selected frequency, the pair of arrays act to produce a dominant bending moment, and, the centre of the diaphragm lies substantially on the axis of the dominant bending moment, wherein, the dominant bending moment is the bending moment produced by the combination of masses which has the greatest magnitude, if they produce more than one bending moment.

Abstract: The present invention provides: a loudspeaker including a frame, a drive unit, and a membrane; the membrane having an inner edge, an outer edge which is suspended from the frame, and a membrane body which is between the inner and outer edges and extends around the drive unit; the drive unit having a stationary part secured to the frame and a translatable part secured to the inner edge of the membrane; the membrane body including a dished portion which, has a depth that increases from said inner and outer edges towards a base region of the dished portion located between said edges; wherein the loudspeaker includes a stiffening element which extends around the drive unit and stiffens the membrane body at the base region of the dished portion, so as to reinforce the membrane against deformation in the base region. By including the stiffening element, it has been found that the first break-up resonance of the membrane is shifted to a higher frequency and has reduced amplitude.

Abstract: A loudspeaker comprising an acoustic panel (1) having two substantially parallel main surfaces (5A, 5B) and comprising an electrical exciter (3) arranged on one of said main surfaces. The panel produces acoustic radiation upon energization of the exciter, at least subsequently as a result of bending waves produced in the panel. In order to improve the energy response of the loudspeaker, the panel has a tuning area (21) extending opposite the exciter, which tuning area has a fundamental resonance frequency which is lower than the fundamental resonance frequency of any similar area in the rest of the panel, if determined under the same conditions.