Patent ID: 6219432
Filing Date: 2001-04-17
Classification: H04R

Abstract:
A loudspeaker drive unit comprising:a diaphragm made of a first material;a chassis member; anda surround made of a second, different, material connecting the periphery of the diaphragm to the chassis member, the surround being made of a body of foam material arranged to be compressed against the chassis member when the diaphragm moves towards the chassis member; wherein:the diaphragm is cone-shaped and has a first, narrow end and a second, broad end,the periphery of the broad end of said diaphragm is joined to the foam by a re-entrant portion, said re-entrant portion extending in a direction toward said narrow end;the area over which the re-entrant portion makes contact with the body of foam material is substantially a line of contact between the circumference of the diaphragm and the foam material, said line of contact being defined by the re-entrant portion of said diaphragm making contact with said foam material at an angle.