Abstract: A flat subwoofer is provided comprising a driver in which a coil is arranged in an air gap in the driver, which coil is connected to a membrane, where the driver is arranged on a chassis, wherein the membrane comprises two interconnected parts, a forward membrane part and rear membrane part, where both membrane parts are substantially symmetrical around an axis perpendicular to the membranes plane, where each membrane part has an outer and an inner periphery where the forward membrane part along an outer periphery is connected to the chassis by a surround, and where the rear membrane part is connected to a spring member which spring member at least partly surrounds the driver.

Abstract: Ring-shaped membrane for an electro-acoustical loudspeaker, where said membrane comprises two or more dome-shaped annulus concentrically arranged around a central portion through which an imaginary axis of symmetry passes, where an outer periphery of said membrane is suitable to be attached to a surround; where the central portion is attached to a tower, which again is fastened to the loudspeakers driver, wherein the angle between a plane being perpendicular to the axis of symmetry and the attachment of the membrane to the surround resp. the tower is in the interval 0° to 40°, most preferred around 30°.

Abstract: Ring-shaped membrane for an electro-acoustical loudspeaker, where said membrane comprises two or more dome-shaped annulus concentrically arranged around a central portion through which an imaginary axis of symmetry passes, where an outer periphery of said membrane is suitable to be attached to a surround; where the central portion is attached to a tower, which again is fastened to the loudspeakers driver, wherein the angle between a plane being perpendicular to the axis of symmetry and the attachment of the membrane to the surround resp. the tower is in the interval 0° to 40°, most preferred around 30°.

Abstract: Ring-shaped membrane for an electro-acoustical loudspeaker, where said membrane comprises two or more dome-shaped annulus concentrically arranged around a central portion through which an imaginary axis of symmetry passes, where an outer periphery of said membrane is suitable to be attached to a surround; where the central portion is attached to a tower, which again is fastened to the loudspeakers driver, wherein the angle between a plane being perpendicular to the axis of symmetry and the attachment of the membrane to the surround resp. the tower is in the interval 0° to 40°, most preferred around 30°.

Abstract: Ring-shaped membrane for an electro-acoustical loudspeaker, where said membrane comprises two or more dome-shaped annulus concentrically arranged around a central portion through which an imaginary axis of symmetry passes, where an outer periphery of said membrane is suitable to be attached to a surround; where the central portion is attached to a tower, which again is fastened to the loudspeakers driver, wherein the angle between a plane being perpendicular to the axis of symmetry and the attachment of the membrane to the surround resp. the tower is in the interval 0° to 40°, most preferred around 30°.

Abstract: Flat subwoofer (1) comprising a driver (10) in which a coil (2) is arranged in an air gap (3) in said driver, which coil is connected to a membrane (4,5), where said driver (10) is arranged on a chassis (11), characterised in that the membrane comprises two interconnected parts, a forward membrane part (4) and rear membrane part (5), where both membrane parts (4,5) are substantially mmetrical around an axis (9) perpendicular to the membranes plane, where each membrane part has an outer and an inner periphery where said forward membrane part (4) along an outer periphery is connected to the chassis (11) by means of a surround (8), and where said rear membrane part (5) is connected to a spring member (15) which spring member at least partly surrounds the driver (10), and where the coil (2) is arranged on a coil cylinder (16), which cylinder is connected either to the inner periphery (13) of the rear membrane part (5) or to the inner periphery of the forward membrane part (4) in which case the forward and rear me

Abstract: Ring-shaped membrane for an electro-acoustical loudspeaker, where said membrane comprises two or more dome-shaped annulus concentrically arranged around a central portion through which an imaginary axis of symmetry passes, where an outer periphery of said membrane is suitable to be attached to a surround; where the central portion is attached to a tower, which again is fastened to the loudspeakers driver, wherein the angle between a plane being perpendicular to the axis of symmetry and the attachment of the membrane to the surround resp. the tower is in the interval 0° to 40°, most preferred around 30°.

Abstract: Membrane construction for a loudspeaker, in particular a cone tweeter membrane construction, where said membrane comprises two concentrically arranged sections, a first inner dome shaped annular membrane section connected or integral with a second outer cone shaped membrane section, where the outer section comprises means for attaching a surround.

Abstract: Ring-shaped membrane for an electro-acoustical loudspeaker, where said membrane comprises two or more dome-shaped annulus concentrically arranged around a central portion through which an imaginary axis of symmetry passes, where an outer periphery of said membrane is suitable to be attached to a surround; where the central portion is attached to a tower, which again is fastened to the loudspeakers driver, wherein the angle between a plane being perpendicular to the axis of symmetry and the attachment of the membrane to the surround resp. the tower is in the interval 0° to 40°, most preferred around 30°.

Abstract: A loudspeaker comprising a moving coil and a membrane fastened to a chassis, where the membrane is divided into a concentrically disposed inner membrane part and a concentrically disposed outer membrane part, whereby a meeting area is defined between the inner membrane part and the outer membrane part, the inner membrane part being fastened to an inner moving coil and the outer membrane part being fastened to an outer moving coil.

Abstract: A loudspeaker comprising a moving coil and a membrane fastened to a chassis, where the membrane is divided into a concentrically disposed inner membrane part and a concentrically disposed outer membrane part, whereby a meeting area is defined between the inner membrane part and the outer membrane part, the inner membrane part being fastened to an inner moving coil and the outer membrane part being fastened to an outer moving coil.

Abstract: A special Hi-Fi tweeter having a ring-shaped dome portion with a retracted central portion fixed to the tweeter chassis was found to present an objectionable drop of response in the 18-20 KHz range. According to the invention this problem is eliminated or minimized in placing in front of said central area a forwardly projecting, generally conical wave guide (18) that will minimize interferences between sound waves radiated forwardly and inwardly from the ring shaped dome. An alternative solution is to arrange, in front of a wider central portion, a shield member directly preventing external radiation from the critical central area, still without changing the shape of the diaphragm. However, also certain modifications are proposed, which may well be used in connection with ordinary dome speakers.

Abstract: In quality loudspeakers there are certain distortion problems owing to a lack of damping of the movements of the outer, free edge of the loudspeaker diaphragm (2). In connection with the invention it has been recognized that these problems are widely due to some special interference phenomena originating from the total movement of the diaphragm, and according to the invention it has been found advantageous to provide, in the area of the outer edge (6) of the diaphragm (2), a differentiation with respect to the effective spring characteristic of the edge suspension (8) of the diaphragm. This is achievable in a variety of manners, e.g. already by a cutting off of pieces of the exterior diaphragm zone as secured to the edge suspension.

Abstract: The invention is a loudspeaker.