Abstract: A suspension, for the voice coil of a loudspeaker drive unit, includes an inner ring to be connected to the voice coil of the loudspeaker drive unit; an outer ring to be connected to the chassis of the loudspeaker drive unit; and a plurality of radial spoke-like members connecting the inner ring to the outer ring. The radial spoke-like members are free of compressive stress between their ends. The spoke-like members are of greater lateral stiffness than the spoke-like member?s and are substantially X-shaped.

Abstract: A diaphragm for a loudspeaker drive unit or for a microphone, the diaphragm including a dome-shaped member of synthetic diamond, wherein the diaphragm includes an integrally-formed, peripheral skirt. The skirt may be of cylindrical form or flared.

Abstract: A loudspeaker system includes a loudspeaker drive unit (1) and a rear sound absorption system (20) having a multiplicity of tubes connected to the rear of the loudspeaker drive unit. In one example, the rear sound absorption system (20) comprises a collector tube (22) for sound waves emerging from a passage in the magnet assembly of the loudspeaker drive unit, an annular diffuser (24) for sound waves coming from the back of the diaphragm (4), and a disk-shaped diffuser (26) for second waves collected by the collector tube (22). The disk-shaped diffuser (26) is part of a basket-like assembly (28) mounted on the rear of the magnet assembly (6). The annular diffuser (24) is mounted against the wall (2) of the enclosure in which the loudspeaker drive unit (1) is mounted. The annular diffuser (24) includes a base portion (24A) with integral upstanding vanes (24B) arranged in a spiral configuration.

Abstract: A suspension, for the voice coil of a loudspeaker drive unit, includes an inner ring to be connected to the voice coil of the loudspeaker drive unit; an outer ring to be connected to the chassis of the loudspeaker drive unit; and a plurality of radial spoke-like members connecting the inner ring to the outer ring. The radial spoke-like members are free of compressive stress between their ends. The spoke-like members are of greater lateral stiffness than the spoke-like member's and are substantially X-shaped.

Abstract: An acoustic structure includes a first, rigid panel (7), a second, rigid panel (11) aligned in spaced, substantially parallel, relationship with the first panel (7), a multiplicity of partition walls (15) running transverse to the panels of the panels (7, 11) and dividing the interior space of the enclosures into a single layer of cells (17) bounded at one face by the inside of the first panel (7) and bounded at the opposite face by the inside of the second panel (11), the partition walls (15) being bonded at the one face to the inside of the first panel (7) and at the opposite face to the inside of the second panel (11), and a multiplicity of apertures (19) in the partition walls (15) providing communication between adjacent cells of the single layer of cells (17).

Abstract: A loudspeaker system comprises a loudspeaker drive unit (1) and a rear sound absorption system (20) comprising a multiplicity of tubes connected to the rear of the loudspeaker drive unit. In one example, the rear sound absorption system (20) comprises a collector tube (22) for sound waves emerging from a passage in the magnet assembly of the loudspeaker drive unit, an annular diffuser (24) for sound waves coming from the back of the diaphragm (4), and a disk-shaped diffuser (26) for sound waves collected by the collector tube (22). The disk-shaped diffuser (26) is part of a basket-like assembly (28) mounted on the rear of the magnet assembly (6). The annular diffuser (24) is mounted against the wall (2) of the enclosure in which the loudspeaker drive unit (1) is mounted. The annular diffuser (24) comprises a base portion (24A) with integral upstanding vanes (24B) arranged in a spiral configuration.

Abstract: An auxiliary bass radiator unit is disclosed for mounting in an aperture in a loudspeaker enclosure. The unit comprises a substantially rigid panel member (10) mounted on a flexable surround member (12) so as to allow the panel member, when mounted, in use, in the aperture to move in sympathy with sound waves within the enclosure. The flexable surround member includes a hinge portion (14) mounting the panel member for movement as a hinged flap. Thus, movement of the panel member in twisting and other undesirable modes is substantially avoided.

Abstract: The loudspeaker system includes a loudspeaker drive unit (2) and a tube (4) acoustically coupled to the rear of the loudspeaker drive unit for leading away and absorbing sound waves produced at the rear of the loudspeaker drive unit. The tube is acoustically coupled to the loudspeaker drive unit by a hollow resonant enclosure (6) and the loudspeaker drive unit is mounted at an aperture (8) in an external wall of the enclosure. The tube communicates with the interior of the enclosure and extends outwardly from the enclosure. There is a significant change in acoustic impedance where the tube communicates with the interior of the enclosure. The fundamental resonant frequencies of the enclosure and the tube each lie between the first and second frequencies but the Helmholtz resonant frequency of the tube, when its distal end is open, lies below the first frequency.

Abstract: A loudspeaker drive unit (1) comprises a diaphragm (2), a chassis member (3) and a surround (4) connecting the outer portion of the diaphragm to the chassis member in which (i) substantially all parts of the surround (4) located between the diaphragm (2) and the chassis member (3) and capable of radiating sound are arranged parallel or at an acute angle with respect to the longitudinal axis of the loudspeaker drive unit (1), or (ii) the surround is made of a body of foam material (30) arranged to be compressed against the chassis member (32) when the diaphragm (10) moves towards the chassis member, or (iii) the bending wave impedance of the surround (30) is matched to the bending wave impedance of the diaphragm (10).

Abstract: An enclosure (1) for a loudspeaker drive unit (5) comprises a chamber (2) defined by one or more walls (3), in which a loudspeaker drive unit (5) is to be mounted. A port member (4) defines a passageway providing fluid communication between the interior and the exterior of the chamber (2). The internal surface (9) of the port member (4) is, at least in part, of a coarse texture. A multiplicity of indentations (11) and/or peaks may provide the coarse texture. This reduces so-called "chuffing" noises caused by air movement through the port member.

Abstract: A multi-way loudspeaker system comprising at least two series connected loudspeakers (Z.sub.H, Z.sub.L) connected to a common signal input (1, 2) for reproducing different parts of the full frequency spectrum of an audio signal applied to the signal input and being provided with a passive dividing network including a first impedance (Z.sub.1) connected in parallel to a first loudspeaker (Z.sub.H) for reproducing a first part of the audio-frequency spectrum and a second impedance (Z.sub.2) connected in parallel to a second loudspeaker (Z.sub.L) for reproducing a second part of the audio-frequency spectrum. The loudspeaker system is provided with a compensating circuit consisting of a transformer (T) and an impedance (Z.sub.

Abstract: A loudspeaker enclosure comprises a rectangular box-like housing (100) consisting of top (102) and bottom walls (104), front and back walls (106), left (108) and right (110) side walls, each of the walls being formed by a wooden panel, a hollow stiffening structure (200) located within the housing (100) and extending from the top wall (102) to the bottom wall (104), from the front wall to the back wall (106), and from the left side wall (108) to the right side wall (110), the hollow stiffening structure (200) comprising a first set of spaced-apart stiffening panels (1,2,3) arranged with their planes substantially parallel to each other and substantially parallel to the walls of a pair (102, 104) of opposed housing walls, and a second set of spaced-apart stiffening panels (4,5) arranged with their planes substantially parallel to each other and substantially parallel to the walls of a different pair (108, 110) of opposed housing walls, the stiffening panels (1,2,3) of the first set being secured to stiffening

Abstract: This invention relates to loudspeaker diaphragms and methods of making such diaphragms. It is an object of the invention to improve damping of standing waves formed in a loudspeaker diaphragm. To this end a diaphragm in accordance with the invention is made of textile material impregnated with a stiffening material which does not completely fill the spaces between the threads of the textile material, said spaces being partially filled with damping material. The textile material is preferably a woven glass-fiber fabric or a fabric woven or knitted from an aramid fiber. The stiffening material is preferably a synthetic resin, for example, a phenolic, epoxy or melamine resin and the damping material is preferably a polyvinyl-acetate emulsion or a vinyl resin-based thermoplastic material of the kind used as a cone edge dampener.