Abstract: A speaker assembly for good thermal management in loudspeakers such as planar magnetic drivers (PMDs). The assembly comprises a front panel with one or more sound openings, one or more PMDs each associated with a respective sound opening, one or more rear thermal plates each associated with a respective PMD structure plate, and a thermal spreader plate. The PMD structure plate is mounted to the front panel, the rear thermal plate is mounted to the associated PMD structure plate, and the thermal spreader plate is mounted to the one or more rear thermal plates, thereby forming a layered heatsink assembly. In a further development, the assembly has multiple PMDs and a circuit configured to modulate power handling and frequency response between the multiple PMDs.

Abstract: A magnetic recoil fastener assembly comprises a fastener with a head and a shank, and two annular magnets. When assembled, the annular magnets are arranged on the shank of the fastener to magnetically repel each other. At least the magnet arranged closer to the head of the fastener has a varying inner diameter of its axial opening, including a first diameter at one end which is larger than the width of the head, and a second diameter which is smaller than the width of the head. The end having the larger first diameter is arranged facing the head of the fastener. Also described are in-wall speaker assemblies including such magnetic recoil fastener assemblies for magnetically mounting speaker grilles in an adjustable manner, as well as methods for installing such in-wall speaker assemblies using such magnetic recoil fastener assemblies.

Abstract: An audio loudspeaker having an induction motor whose yoke components are formed of powdered iron or other material which is highly magnetically permeable and highly electrically resistive. The oscillating magnetic flux caused by the alternating current applied to the primary coil induces eddy currents in the shorted turn secondary coil but not in the yoke components. This reduces heating of the yoke components, reduces flux modulation, and reduces wasted power.

Abstract: A mass notification system (MNS) loudspeaker having very high intelligibility. The MNS loudspeaker includes a plurality of transducers arranged in a symmetric pattern around an axis, so as to produce a substantially cylindrical wave front of sound pressure. The loudspeakers are coupled to a cap, and form a cylinder whose inner diameter is large enough to slip over a pole to which the loudspeakers are to be mounted. The under side of the cap may rest atop the pole. An inner cylinder encloses an air volume behind the transducers for acoustic loading and environmental protection of the transducers. An optional telescoping stand retracts into the inner cylinder.

Abstract: An audio loudspeaker having an induction motor whose yoke components are formed of powdered iron or other material which is highly magnetically permeable and highly electrically resistive. The oscillating magnetic flux caused by the alternating current applied to the primary coil induces eddy currents in the shorted turn secondary coil but not in the yoke components. This reduces heating of the yoke components, reduces flux modulation, and reduces wasted power.

Abstract: An electromagnetic transducer such as an audio loudspeaker, whose diaphragm assembly and motor both have a highly elongated shape in which the long dimension is at least 3× greater than the short dimension. The diaphragm may be obround, and the motor's magnetic air gap may comprise a pair of elongated, parallel, linear gaps. A novel “boxcar” device is used to hold the bobbin and voice coil in an obround shape, maintaining the parallel, linear shape of their elongated sides. The lower suspension may be disposed only at the ends of the motor, enabling the narrowest possible configuration.

Abstract: An electromagnetic transducer such as an audio loudspeaker, whose diaphragm assembly and motor both have a highly elongated shape in which the long dimension is at least 3× greater than the short dimension. The diaphragm may be obround, and the motor's magnetic air gap may comprise a pair of elongated, parallel, linear gaps. A novel “boxcar” device is used to hold the bobbin and voice coil in an obround shape, maintaining the parallel, linear shape of their elongated sides. The lower suspension may be disposed only at the ends of the motor, enabling the narrowest possible configuration.