Self-cooled magnetic structure for loudspeakers

A self-cooled electrodynamic loudspeaker comprising a frame, a reciprocating diaphragm connected to a voice coil, and a magnetic structure comprising a pole piece constructed from a material capable of carrying magnetic flux and a magnet arranged located between a top and back plates and around the pole piece, the coil being capable of moving reciprocatingly between said pole piece and magnet under the effect of a magnetic flux created across a magnetic gap formed between the pole piece and the top plate and magnet, wherein the improvement consists of at least two channels adjacent to the voice coil for the passage of air driven by the movement of the diaphragm in response to current passing to the voice coil, each channel continuously extending from an upper face of the pole piece, partially along the periphery of the pole piece and into a central cavity of the pole piece, the cavity being closed at the upper face of the pole piece and open into a lower face of the piece.

A self-cooling pole piece for loudspeakers comprising a pole piece constructed from a material capable of carrying magnetic flux, the piece forming part of a magnetic structure of the loudspeaker, the magnetic structure comprising the pole piece and a magnet located between a top and a back plates, the pole piece defining a periphery adjacent a voice coil, wherein the periphery of the pole piece includes at least two channels for circulation of cooling air, the channels continuously extending from an upper face of the pole piece, radially inwardly and downwardly into a central cavity of the pole piece, the cavity being closed by a conical wall at an upper end of the pole piece and open into a lower end of the pole piece.