# US 12,003,935 B2 · Loudspeaker with a non-uniform suspension and an enforcement element > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,003,935 B2 - Document ID: US12003935B2 - Status: Granted - Kind: B2 - Application number: 17/594,315 - Filed: 2020-04-08 - Published: 2022-05-26 - Granted: 2024-06-04 - Earliest claimed: 2019-04-11 - Assignees: Purifi Aps - Applicants: Purifi Aps - Inventors: Bruno Putzeys; Lars Risbo; Carsten Tinggaard - Web page: https://patentgrep.com/patent/US12003935B2 ## CPC - H04R 7/20: Securing diaphragm or cone resiliently to support by flexible material, springs, cords, or strands - H04R 7/18: at the periphery - H04R 9/06: Loudspeakers - H04R 2207/021: Diaphragm extensions, not necessarily integrally formed, e.g. skirts, rims, flanges - H04R 2307/207: Shape aspects of the outer suspension of loudspeaker diaphragms - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract A loudspeaker with a non-uniform surround, a membrane and a stiffening element preventing the surround from flexing the membrane during operation. A non-uniform surround does not have the same cross section, along the radius of the speaker if circular, all around the perimeter of the membrane as some portions will be upwardly directed and other portions downwardly directed. ## Claims ### Claim 1 A loudspeaker comprising a motor, a membrane, a surround and a frame, where: the motor is configured to move the membrane upwardly and downwardly along an axis, the membrane has an outer edge, the surround is connected to the frame and at least substantially all of the outer edge of the membrane, the surround has a first portion and a second portion, where: the first portion has a first radial cross section extending from a third portion of an outer edge of the membrane to a point of the frame being the closest to the third portion, which first portion is directed upwardly, and the second portion has a second radial cross section extending from a fourth portion of an outer edge of the membrane to a point of the frame being the closest to the fourth portion, which second portion is directed downwardly, the loudspeaker further comprising a stiffening element provided at the outer edge of the membrane, wherein a portion of the surround, between the first and second portions, has a cross section with an M or W shape. ### Claim 2 (depends on 1) The loudspeaker according to claim 1, wherein the first and/or second radial cross section has a U or V shape. ### Claim 3 (depends on 1) The loudspeaker according to claim 1, wherein the surround defines, along a central, closed curve thereof, a repeating pattern. ### Claim 4 (depends on 1) The loudspeaker according to claim 1, wherein the stiffening element has a portion with a radial cross section which has a shape of a closed curve. ### Claim 5 (depends on 4) The loudspeaker according to claim 4, wherein the stiffening element is hollow. ### Claim 6 (depends on 4) The loudspeaker according to claim 4, wherein the stiffening element is filled by a filling material. ### Claim 7 (depends on 4) The loudspeaker according to claim 4, wherein the stiffening element has a portion with a radial cross section which has a shape of a polygon. ### Claim 8 (depends on 7) The loudspeaker according to claim 7, wherein one side of the polygon is formed by the membrane. ### Claim 9 (depends on 4) The loudspeaker according to claim 4, wherein the stiffening element has a portion with a radial cross section which is oval. ### Claim 10 (depends on 1) The loudspeaker according to claim 1, wherein the stiffening element forms a closed curve in a predetermined plane. ### Claim 11 (depends on 10) The loudspeaker according to claim 10, wherein the combined membrane and stiffening element has, when projected on to the plane, a mass per area which is higher at the stiffening element than inside the closed curve. ### Claim 12 (depends on 10) The loudspeaker according to claim 10, wherein the combined membrane and stiffening element has, in a direction perpendicular to the plane, thickness which is higher at the stiffening element than inside the closed curve. ### Claim 13 (depends on 1) The loudspeaker according to claim 1, wherein the membrane and the stiffening element have a first mass per area, in a plane perpendicular to a direction of movement of the membrane, and the membrane has a second mass per area in the plane at a position not at the stiffening element, where the first mass per area is higher than the second mass per area. ### Claim 14 (depends on 1) The loudspeaker according to claim 1, wherein the stiffening element is configured to prevent flexure of the outer edge of the membrane during movement of the membrane. ### Claim 15 (depends on 1) The loudspeaker according to claim 1, wherein the membrane is funnel-shaped. ### Claim 16 A method of assembling a loudspeaker, the method comprising: providing a membrane having an outer edge, providing a frame, providing a surround having a first portion and a second portion, where: the first portion has a first radial cross section extending from a third portion of an outer edge of the membrane to a point of the frame being closest to the third portion, which first portion is directed upwardly, and the second portion has a second radial cross section extending from a fourth portion of an outer edge of the membrane to a point of the frame being the closest to the fourth portion, which second portion is directed downwardly, wherein a portion of the surround, between the first and second portions, has a cross section with an M or W shape, providing a stiffening element and fixing the outer edge of the membrane to the surround and the stiffening element.