Abstract: An electro-acoustic drive unit includes at least one permanent magnet assembly and at least an inner pole piece and an outer pole piece forming a pair of pole pieces, the permanent magnet assembly together with the pair of pole pieces forming a magnetic circuit with a pole gap for exciting a voice coil assembly. The pole gap is arranged to provide a magnetic field directed radially with respect to a center axis of the loudspeaker, and the permanent magnet assembly includes at least two permanent magnetic bars, with radially extending magnetization direction with respect to the center axis of the loudspeaker.

Abstract: A loudspeaker drive unit includes at least one voice coil, a diaphragm, permanent magnet element and pole piece element. The permanent magnet element and pole piece element form a magnetic circuit with a pole gap arranged to receive and interact with the voice coil. The magnetic circuit is arranged to provide a magnetic field directed radially in the pole gap. The voice coil, the diaphragm and a support structure forms a voice coil and diaphragm assembly, which is arranged to be a self-supported unit. The voice coil and diaphragm assembly is removable from the magnetic circuit as a separate unit, allowing convenient replacement of the dynamic parts of the loudspeaker drive unit.

Abstract: An electro-acoustic drive unit including at least a first and a second drive unit, each provided with a pole gap for exciting respective voice coil assemblies, at least one permanent magnet means is arranged to be a part of the magnetic circuit of both the first and the second drive unit. The pole gaps are arranged to provide magnetic fields directed radially with respect to a center axis of the loudspeaker, and the permanent magnet means has radially extending magnetization direction with respect to the center axis of the loudspeaker.

Abstract: A high frequency drive unit comprising a dome-type diaphragm in a diaphragm and voice coil assembly. The diaphragm and voice coil assembly is particular suitable for use in compound loudspeakers with a plurality of drive units adapted to reproduce different part of the audio frequency spectra and which drive units are arranged in a co-axial configuration. The diaphragm of the diaphragm and voice coil assembly according to the invention has a circular cut out at its top defining an inner periphery of the diaphragm dome. The diaphragm is suspended on its inner periphery by a top annular suspension, at the outer periphery by an outer annular suspension extending outwards in a radial direction and at the outer periphery by an inner annular suspension extending inwards.

Abstract: A loudspeaker drive unit includes at least one voice coil, a diaphragm, permanent magnet element and pole piece element. The permanent magnet element and pole piece element form a magnetic circuit with a pole gap arranged to receive and interact with the voice coil. The magnetic circuit is arranged to provide a magnetic field directed radially in the pole gap. The voice coil, the diaphragm and a support structure forms a voice coil and diaphragm assembly, which is arranged to be a self-supported unit. The voice coil and diaphragm assembly is removable from the magnetic circuit as a separate unit, allowing convenient replacement of the dynamic parts of the loudspeaker drive unit.

Abstract: An electro-acoustic drive unit includes at least one permanent magnet assembly and at least an inner pole piece and an outer pole piece forming a pair of pole pieces, the permanent magnet assembly together with the pair of pole pieces forming a magnetic circuit with a pole gap for exciting a voice coil assembly. The pole gap is arranged to provide a magnetic field directed radially with respect to a center axis of the loudspeaker, and the permanent magnet assembly includes at least two permanent magnetic bars, with radially extending magnetization direction with respect to the center axis of the loudspeaker.

Abstract: An electro-acoustic drive unit including at least a first and a second drive unit, each provided with a pole gap for exciting respective voice coil assemblies, at least one permanent magnet means is arranged to be a part of the magnetic circuit of both the first and the second drive unit. The pole gaps are arranged to provide magnetic fields directed radially with respect to a center axis of the loudspeaker, and the permanent magnet means has radially extending magnetization direction with respect to the center axis of the loudspeaker.

Abstract: A compound loudspeaker drive unit comprising a first drive unit and a second drive unit arranged co-axial with respect to the center axis of the loudspeaker, and each drive unit comprises permanent magnet means and pole piece means together forming a magnetic circuit with a pole gap for exciting a voice coil assembly, each pole gap providing magnetic field directed radially with respect to a center axis of the loudspeaker. At least one of the permanent magnet means has a radially extending magnetization direction with respect to said center axis of the loudspeaker and the acoustic centers of said drive units substantially coincide.

Abstract: A compound loudspeaker drive unit comprising a first drive unit and a second drive unit arranged co-axial with respect to the center axis of the loudspeaker, and each drive unit comprises permanent magnet means and pole piece means together forming a magnetic circuit with a pole gap for exciting a voice coil assembly, each pole gap providing magnetic field directed radially with respect to a center axis of the loudspeaker. At least one of the permanent magnet means has a radially extending magnetization direction with respect to said center axis of the loudspeaker and the acoustic centers of said drive units substantially coincide.