The invention relates to a loudspeaker, which contains bearing structure, a magnetic arrangement (12) fixed to the bearing structure, determining air-gaps (13), and a diaphragm connected to the bearing structure, made of a sheet material. The diaphragm has the shape of a cylindrical jacket consisting of segments (10), the segments (10) are connected to each other along delimiting lines running in the direction of the generating lines, and they have a surface the curvature of which is larger than the curvature that belongs to the overall radius of the cylindrical jacket-like shape, there is a flap (11) at least along two delimiting lines, which flaps (11) extend into an air-gap (13) each radially, and the diaphragm is connected to the bearing structure with flexible supporting units joining the flaps (11) and allowing radial movement of the flaps (11) in the air-gap (13).