A molded pressure ring adapted primarily for holding the peripheral marginal portion of a diaphragm in a tone generator under uniform light pressure so that the tone does not change significantly under normal changes in ambient conditions of temperature and pressure; more particularly the ring comprises an outer annular body having circumferentially equi-spaced, radially inwardly extending, generally U-shaped, independently movable, flexible and resilient cantilevers provided at the free ends thereof with pressure applicators arranged to engage and hold the diaphragm under pressure exerted by torsion-stressed portions of the cantilevers.