Abstract: A method of improving the modal resonance frequency distribution of a panel for a distributed resonant mode bending wave acoustic device. The method involves analysing the distribution of the modal resonance frequencies of the panel, identifying a modal resonance frequency that is non-uniformly spaced relative to adjacent modal resonance frequencies, identifying a location on the panel that exhibits anti-nodal behaviour at the identified modal resonance frequency, and changing the local impedance to bending wave vibration at that location. The method has particular application to distributed mode loudspeakers.

Abstract: At improved loudspeaker system for a passenger vehicle such as an automobile is disclosed. The system comprises a transducer capable of being excited by applied electric potential and electronic means that is electrically connected to the transducer to apply electric potential thereto. It is a feature of the present invention that the diaphragm driven by the excited transducer is comprised of the trim panel of the vehicle.

Abstract: Active acoustic device comprises a panel member (11) having distribution of resonant modes of bending wave action determining acoustic performance in conjunction with a transducer (31-34). The transducer (31-34) is coupled to the panel member (11) at a marginal position. The arrangement is such as to result in acoustically acceptable action dependent on said distribution of active said resonant modes. Methods of selecting the transducer location, or improvement by location of localized marginal clamping, rely on assessing best or better operative interaction of said transducer (31-34) and the panel members (11) according to parameters of acoustic output for the device as an acoustic radiator.

Abstract: A bending wave panel loudspeaker with a bending wave acoustic panel that is capable of supporting bending wave vibration. The panel has a front face and a rear face, and a transducer mounted on the panel to excite bending wave vibration in the panel in response to an electrical signal applied to the transducer so that sound energy is radiated from both the front and the rear faces of the panel. An acoustically porous resistive structure is mounted proximate to one face of the panel to resistively impede sound energy radiated from that one face.

Abstract: A panel-form loudspeaker having a member capable of sustaining and propagating input vibrational energy by bending waves, and a transducer mounted on the member for applying a local couple to the member. The motor coil assembly of the transducer has a surrounding attachment portion rigidly attached to one face of the member in spaced relation to the central attachment portion of the magnet assembly of the transducer. When the transducer is energized, the motor coil assembly and the magnet assembly move in opposite directions to apply a couple to the member through their respective spaced attachment portions to launch bending waves into the member.

Abstract: A loudspeaker comprises a panel member (11, 21, 31, 41, 61, 71, 81, 91) as resonant acoustic radiator relying on bending wave action and a driver (12, 22, 32, 42, 62, 72, 82, 92) coupled to the panel member to cause bending waves therein. The panel member has its mass and/or bending capability of the panel member locally altered or otherwise different, particularly locally of the driver as coupled to the panel member. Local holes (16, 26, 36, 46), affixed mass (66) or affixed damping material (76) are effective to reduce high frequency due to drumming effects at the driver coupling (17, 37, 47, 67, 77, 87).

Abstract: An acoustic device having a panel-form member adapted to support bending wave vibration and having a frequency distribution of resonant bending wave modes. The member is of substantially triangular form with the parameters of the member being selected to provide a desired frequency distribution of resonant modes. At least one of the parameters is selected from the ratio of the effective lengths of two of the sides of the triangular form, the effective angle between at least two of the sides of the triangular form, and the curvature of at least one side.

Abstract: A mobile telephone (10) comprising a body (12) and a bending wave loudspeaker which comprises a panel-form member (14) capable of supporting bending waves and a transducer (24) mounted to the panel-form member to excite bending wave vibration in the panel-form member to produce an acoustic output. The body (12) defines an open-faced cavity (16) and the panel-form member is movable between first and second positions with the panel-form member covering the open face of the cavity (16) when in the first position, and spaced away from the cavity when in the second position.

Abstract: A thin loudspeaker is provided that produces a superior frequency response and a diffuse acoustical pattern using magnetic drivers, acoustical plates, or a combination of magnetic drivers and acoustical plates. The invention contains a specially designed crossover network and a novel enclosure design. The novel enclosure includes a septum and cross bracing which enables the invention to realize superior performance in a thin loudspeaker design. The invention encompasses methods for improving the performance of an acoustical plate which include (1) placing acoustical plate motor elements on the plate in a manner that avoids rotational, mirror, and translational symmetry, (2) using acoustical plate motor elements of different shapes and sizes to stimulate the plate, and (3) using an acoustical plate that has an asymmetric shape. All of the embodiments of the invention may be covered with a decorative cover and hung on a wall like a picture or used to form a panel in a home entertainment center.

Abstract: A loudspeaker includes an assembly of at least two bending wave panel-form acoustic members each having a set of modes which are distributed in frequency. The parameters of at least two of the acoustic members are selected so that the modal distributions of each acoustic member are substantially different. The arrangement is such that the modal distributions of the assembly of acoustic members are interleaved constructively in frequency. A transducer applies bending wave energy to the acoustic members to cause them to resonate to produce an acoustic output. A method of making such a loudspeaker is also provided.

Abstract: A loudspeaker includes a box-form structure made from stiff lightweight sheet material to define a plurality of faces, at least one face of the structure forming a panel-form bending wave acoustic radiator, and an electro-acoustic vibration transducer coupled thereto to apply bending wave energy to the radiator to cause it to radiate an acoustic output when an input signal is applied to the transducer. The box-form structure is collapsible, so that the box-form structure can be stored and transported in a flat form and erected as a box when required as a loudspeaker.

Abstract: A bending wave panel-form acoustic radiator formed from sheet material to define an acoustically active area and having at least one integral stiffening member in the form of a corrugation extending out of the plane of the sheet and at least partially across the acoustically active area of the radiator, which stiffening member is of substantially U-shaped cross section. Also disclosed is a method of making a bending wave panel-form acoustic radiator, comprising forming a sheet into a panel having at least one integral corrugation member extending out of the plane of the sheet and at least partly across the sheet and of substantially U-shape cross-section, to stiffen the sheet to have a desired ability to support and propagate bending waves.

Abstract: An acoustic device has a plurality of resonant bending wave modes along the length of a member. The fundamental frequency of resonant bending wave modes in directions perpendicular to the length is much higher, so that the lower frequency resonant bending wave modes are substantially one directional. A plurality of transducers may be spaced across the width of the member at a preferred position along the length of the panel.

Abstract: A combination panel-form loudspeaker/light comprising a panel having a front face and rear face, a vibration exciter mounted to the member to excite bending-wave vibration in the member, and a light emitter mounted at or adjacent to the panel and arranged to illuminate an area adjacent to the panel.

Abstract: Acoustic devices have members extending transversely of thickness and capable of sustaining bending waves causing consequential acoustic action by reason of areal distribution of resonant modes of natural bending wave vibration consonant with required achievable acoustic action of said member over a desired operative acoustic frequency range, Areal distribution of stiffness including variation(s) therein is used to get desired locations for bending wave transducers and/or good resonant mode acoustic action from inherently unfavourable shapes of members. Members with combined pistonic active drive and bending wave excitement at centers of mass and geometry are featured.

Abstract: Acoustic devices rely on bending wave action in a panel member, particularly distribution of resonant modes of such bending wave action and related acoustically significant surface vibration over area of said panel member favourable to desired or at least acceptable acoustic device performance. The devices comply with selecting parameters of said panel member affecting said distribution, including configuration/geometry and/or bending stiffness(es), and/or location(s) of bending wave transducer(s) in said area of said panel member; the selecting being in accordance with analytical assessment of power transfer related characteristic(s) of said panel member thus said acoustic device concerned and desiderata therefor correlating with achieving said acoustic device performance.

Abstract: A loudspeaker comprising a panel-form acoustic member adapted for operation as a bending wave radiator and an electrodynamic moving coil transducer having a voice coil mounted to the acoustic member to excite bending wave vibration in the acoustic member. The junction between the voice coil and the acoustic member is of sufficient length in relation to the size of the acoustic member to represent a line drive such that the acoustic member has a mechanical impedance which has a rising trend with bending wave frequency.

Abstract: Multi-functional electro-acoustic apparatus has a bending wave panel loudspeaker, an input device (11) forming part of the surface of the bending wave panel (5), and means (13) for providing force feedback to the input device. An electro-acoustic transducer (15) attached to the bending wave panel excites bending waves in the panel to produce an acoustic output. The panel (5) provides several functions and may be considered to be a hyper-functional surface (HFS).

Abstract: Packaging comprises a loudspeaker which has a board component that forms a part of the packaging and acts as a distributed mode bending wave acoustic radiator. A transducer is mounted wholly and exclusively on the radiator to vibrate it and cause it to resonate.