Abstract: An annular surround for a loudspeaker cone wherein a radial cross-section of the surround varies around the circumferential extent of the surround, so as to accommodate peripheral expansion or contraction of the surround by bending. Thus a trough shaped cross-section of the surround may vary sinusoidally with angle around the polar axis of the surround between a semicircular and semielliptical cross-section. The trough section may bland to an adjacent portion of the surround by a fillet which also varies sinusoidally in cross-section in phase with the variation of the trough.

Abstract: A method of manufacturing a loudspeaker diaphragm comprising moulding it from a flowable polyolefin or other plastics material such that part of the material flows during moulding a distance equal to at least 300 times the thickness of that part of material after moulding, the moulded material having a Youngs Modulus of at least 2000 MPa.