Abstract: The support (17) forming the element has a diameter of a magnitude order higher than its height which is itself of a magnitude order higher than its thickness. It is rigidified by means of two membranes each formed of a composite collar including, between the support (17) and a concentric rigid crown (23, 24), an elastomer ring (22) adhered thereto and presenting an axial height of the same order of magnitude as its radial thickness. These rings provide, on the one hand, for the elastic return of the support in axial displacement and, on the other hand, for the preservation of the circularity and therefore for the inherent flatness of said support.

Abstract: A pneumatic loudspeaker with a continuous pressurized fluid flow modulated by an obstacle forming an integral part of a moving armature with an electromagnetic coil supported by a leakproof elastic membrane. The moving armature comprises a cylindrical support and a winding housed in a flat groove made in the body of the support, the winding and its support forming a rigid integral assembly, the winding being sandwiched between a first layer of glue coating the bottom of the flat groove and a second layer of the glue submerging the turns of the winding and endowing the assembly with a smooth and uniform surface.