The invention relates to acoustic transducers which comprise a ceramic ring formed from a pre-stressed set of segments. It consists in using, as screws for tightening pre-stressing wedges, screws with hexagonal heads and in placing on the inner face of these wedges a plate provided with recesses in which the cants of these screw heads become anchored. This plate comprises transverse channels allowing the passage of the power supply wires for the sectors. The central screw is removed after the desired pre-stressing has been obtained. It makes it possible to improve the manufacture of these transducers.