Abstract: An electrodynamic actuator (1a . . . 1c) for a plate like structure (25) or membrane (2) is disclosed, which comprises a voice coil (7, 7a, 7b), a magnet system (8) and a plurality of arms (17a . . . 17t) coupling the voice coil (7, 7a, 7b) and the magnet system (8) in a movable manner. The arms (17a . . . 17t) are made of a metal with a fatigue strength of at least 370 N/mm2 or an ultimate tensile strength of at least 1100 N/mm2. Each of the arms (17a . . . 17t) comprises at least two arm sections (s, s1, s2), which are arranged movable to each other, and which are connected to each other by means of a damping material (18a . . . 18g) with a tensile storage modulus of 0.1-6000 MPa and a tensile loss factor of at least 0.1, each measured at room temperature of 20° C. Moreover the invention relates to speaker (5) and an electrodynamic transducer (26a, 26b) with such an electrodynamic actuator (1a . . . 1c) and a method of manufacturing an intermediate product for such an electrodynamic actuator (1a . . . 1c).

Abstract: A method of thinning a multilayer laminate material used for a membrane stiffening plate is provided to obtain a membrane stiffening plate having a thickness less than currently known in the art. The method provides for a significant reduction in the thickness of a membrane stiffening plate and provides for a mechanism to tune the cut-off frequency of a loudspeaker on which the membrane stiffening plate is used.

Abstract: A method of thinning a multilayer laminate material used for a membrane stiffening plate is provided to obtain a membrane stiffening plate having a thickness less than currently known in the art. The method provides for a significant reduction in the thickness of a membrane stiffening plate and provides for a mechanism to tune the cut-off frequency of a loudspeaker on which the membrane stiffening plate is used.