Abstract: A loudspeaker comprises a frame, a cone assembly which includes a cone body having an outer periphery spaced away from the frame, and a flexible annular surround connecting the periphery of the cone body to the frame. The surround has an inner peripheral flange secured to the outer periphery of the cone body, an outer peripheral flange secured to the frame, and an arched web between the two flanges and spanning the gap between the cone body and the frame. The radial cross-section of the arched web has a varying radius of curvature with a greater radius at the bases thereof than at the apex. The preferred cross-sectional configuration is a parabola. The arched web decreases in thickness from the bases thereof toward the apex so that the minimum thickness is located at the apex of the arch and the maximum thickness is located at the bases of the arch. The surround is made of a solid resilient material having a durometer of less than about 55, preferably a rubber such as butyl.

Abstract: A cone for a loudspeaker in which the shear function is more nearly the same at all radii, the shear function being the product of the effective axial thickness at a given radius multiplied by the circumferential length at such radius. The cone is preferably of curved or "exponential" cross section, deeply angled at a central throat but flattening out to approach a plane at the periphery. The cone is made of light, dimensionally stable material characterized by a high velocity of sonic conduction and is preferably in the form of hollow spheres of glass of small dimension in a binder of epoxy or the like. In an alternate embodiment the cone is made of a hard solid acrylic plastic in thin section and with supporting ribs to provide both rigidity and a substantially constant shear function. Encircling the cone is a flexible hinge or "surround". Interposed between the hinge and the edge of the cone is a light collar having axial rigidity to ensure that the edge of the cone remains in a planar locus.