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. A "framed ladder" of heat-conducting bars may be attached to the diaphragm and frame to facilitate heat dissipation from the diaphragm to the frame.