Abstract: An electro-dynamic acoustic transducers has a pleated diaphragm in which an accordion-like alternating movement of the adjacent pleats is perpendicular to the radiation (acoustic) axis of the transducer. Formed metal combs having teeth in the spaces between at least some of the folds provide a precise corrugation and a reliable mechanical attachment between the diaphragm and the frame, with providing better thermal transfer from the diaphragm to the frame. The frame is preferably constructed from a material having high thermal conductivity (such as aluminum) for better heat-transfer and additional heat-dissipation. At least one of the metal combs is resiliently mounted to the frame by a spring, or by means of an elastic or pneumatic mechanism. This enables the diaphragm to remain under tension, counteracting any rippling that might result from the thermal expansion of the dielectric substrate and conductive strands within the frame.

Abstract: An ultrasonic emitter device having broad frequency range capacity with relatively large diaphragm displacement compared to typical electrostatic diaphragm movement. The device includes a core member able to establish a variable magnetic field adjacent the core member. A movable diaphragm is stretched along and displaced a short separation distance from the core member to allow an intended range of orthogonal displacement of the diaphragm within a strong portion of the magnetic field. At least one conductive ring disposed on the movable diaphragm within the influence of the variable magnetic field of the core member for enabling current flow through the ring for developing a second magnetic field which interacts with the first magnetic field to repel and relax the diaphragm at a desired frequency for development of a series of compression waves which may be adjusted to include an ultrasonic frequency range.

Abstract: An elongated, electrically conductive diaphragm is placed in a strongly magnetic field to produce a linear and an elongated sound source giving a high sound energy. At least two elongated diaphragms are positioned between intermediate and enclosing protected magnet elements, whereby the transverse length of the diaphragms are at least of the same size as that of the intermediate protected magnet elements. In this way, a sound without considerable interference merges at a short distance from the sources of the sound. By placing additional such sources of sound alongside each other, a broad sound source with a surface producing an essentially homogeneous sound field is achieved.

Abstract: Planar magnetic transducers including diaphragms having electrical conductors thereon which are mounted within frames so that spaced magnets are disposed on opposite sides of central sound producing surface areas of the diaphragms. Pole elements are provided in spaced relationship between each of the magnets and extend inwardly toward the diaphragms so to form pole extensions for causing magnetic flux from the poles of the magnets proximate to the diaphragms to extend more densely and generally parallel to the electrical conductors between the magnets and the pole elements. Openings for acoustic waves are provided between the pole elements and adjacent magnets.