Patent ID: 8014555

Claim:
An electromagnetic transducer comprising: a diaphragm including a flexible diaphragm portion reciprocatively movable relative to a central axis; a magnetic assembly axially spaced from the diaphragm, the magnetic assembly having a gap annularly disposed about the central, axis and a plurality of air passages; a housing disposed around a central axis, the housing having an upper frame portion surrounding the diaphragm and a lower frame portion surrounding the magnetic assembly, the housing having an interior region forming an axial space between the diaphragm and the magnetic assembly, the lower frame portion formed to support the magnetic assembly and formed with a plurality of apertures aligned with the plurality of air passages in the magnetic assembly to provide a plurality of air flow paths from the interior region into the ambient environment outside the housing; an electrically conductive coil mechanically communicating with the diaphragm, the coil having a plurality of coil portions including at least a first coil portion and a second coil portion axially spaced from each other and at least, partially disposed in the gap, whereby the plurality of air flow paths are in proximate thermal contact with the plurality of coil portions, the air, flow through the air passages is generated by movement of the flexible diaphragm portion in response to movement of the coil, and the air flow through the plurality of air flow paths transfers heat from the transducer to the ambient environment.