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: Trace runs for Planar Line Source Transducers (or speakers) are separated into multiple trace circuits which are electrically isolated but occupy the same area on the planar film. The separate trace runs are then driven with different electrical signals with tailored spectral content in order to achieve an overall acoustical frequency response. By having the separate trace runs occupy the same area, the line source nature of the transducer is preserved over the entire intended spectral response of the transducer and the mechanical structure is also kept simple. External spectral filtering circuits are used to pre-shape the spectral signal into each individual trace run and in most cases, the filtering components are passive and inexpensive.