Abstract: A loudspeaker chassis assembly (2) comprises a loudspeaker chassis (4) and one or more mass damping elements (6), which dampen vibration of the chassis (4). The mass damping elements (6) may be directly attached to the chassis (4) and may be tuned to dampen one or more particular vibrational modes of the chassis (4).

Abstract: A loudspeaker chassis assembly (2) comprises a loudspeaker chassis (4) and one or more mass damping elements (6), which dampen vibration of the chassis (4). The mass damping elements (6) may be directly attached to the chassis (4) and may be tuned to dampen one or more particular vibrational modes of the chassis (4).

Abstract: A loudspeaker enclosure defined by one or more panels housing a drive unit. The drive unit includes a coil, a diaphragm, and a magnet. The magnet is decoupled from the one or more panels of the loudspeaker enclosure. Sound is generated by the movement of the diaphragm and complementary movement of the magnet, on application of an appropriate electrical signal to the coil. The moving diaphragm acts against a first volume of air within the enclosure, while the movement of a surface coupled to the magnet, acts against a second air volume, different from the first volume. The surface coupled to the magnet is decoupled from the one or more panels of the loudspeaker enclosure.

Abstract: A loudspeaker enclosure defined by one or more panels housing a drive unit. The drive unit includes a coil, a diaphragm, and a magnet. The magnet is decoupled from the one or more panels of the loudspeaker enclosure. Sound is generated by the movement of the diaphragm and complementary movement of the magnet, on application of an appropriate electrical signal to the coil. The moving diaphragm acts against a first volume of air within the enclosure, while the movement of a surface coupled to the magnet, acts against a second air volume, different from the first volume. The surface coupled to the magnet is decoupled from the one or more panels of the loudspeaker enclosure.

Abstract: A loudspeaker enclosure for mounting in an aperture in a cavity wall with a part of the enclosure being located within the wall cavity adjacent the aperture, comprises a main enclosure unit for mounting in the aperture and housing one or more loudspeaker drive units, and a supplementary enclosure unit for location within the wall cavity and being acoustically connected in use to the main unit to increase the effective internal volume of the enclosure beyond that of the main unit. The supplementary unit is connected to the main unit by an articulated connection enabling the main unit to be angled relative to the supplementary unit while the supplementary unit is being inserted through the aperture and into the wall cavity, and enabling the main unit to be aligned with and acoustically coupled to the supplementary unit when the main unit is positioned in the wall aperture.

Abstract: A loudspeaker enclosure for mounting in an aperture in a cavity wall with a part of the enclosure being located within the wall cavity adjacent the aperture, comprises a main enclosure unit for mounting in the aperture and housing one or more loudspeaker drive units, and a supplementary enclosure unit for location within the wall cavity and being acoustically connected in use to the main unit to increase the effective internal volume of the enclosure beyond that of the main unit. The supplementary unit is connected to the main unit by an articulated connection enabling the main unit to be angled relative to the supplementary unit while the supplementary unit is being inserted through the aperture and into the wall cavity, and enabling the main unit to be aligned with and acoustically coupled to the supplementary unit when the main unit is positioned in the wall aperture.

Abstract: A diaphragm for a loudspeaker drive unit (1), the diaphragm comprising a block of material having a first, sound-radiating front face (20) and a second, rear face (22). The block is stiffened by being bound about over the first and second faces (20,22) by a multiplicity of turns of one or more elongate members of flexible material (36) stiffened by a stiffening composition.

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 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: 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 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: 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.