A loudspeaker having a frame, a diaphragm, a support element for the diaphragm, and a magnetic circuit that includes a yoke, a core and a magnet. The yoke and the core form an air gap. An upper portion of a coil is connected to the diaphragm and a lower portion of the coil is in the air gap. The diaphragm includes inner, outer and intermediate annular portions. The inner annular portion includes an arch-shaped first central section and a first inner edge connected to the support element and a first outer edge. The outer annular portion includes an arch-shaped second central section, a second inner edge and a second outer edge connected to the frame. The intermediate annular portion includes a dome-shaped section with downwardly-facing concavity and from which a funnel-shaped section extends. The funnel-shaped section converges towards the support element and is connected to the first outer edge.

An object of the present invention is to provide a magnetic circuit for an acoustic transducer, the magnetic circuit enabling peeling of the surface of a member formed by compression-molding a soft magnetic composite material to be suppressed. The present invention is a magnetic circuit for an acoustic transducer, the magnetic circuit including: a yoke 151; a magnet 152; and a top plate 153, wherein the yoke 151 includes a bottom surface portion 151a and a pole piece 151b provided perpendicular to the bottom surface portion 151a, the magnet 152 and the top plate 153 are provided in that order on the bottom surface portion 151a, a magnetic gap 141 in which a voice coil 14 is disposed is formed between the pole piece 151b and the top plate 153, at least one of the pole piece 151b and the top plate 153 includes: a composite material part 154 in a position facing the magnetic gap 141; and a protective layer 155 covering at least a surface of the composite material part 154, the composite material part 154 is formed from a soft magnetic composite material, and the material of the protective layer 155 differs from the soft magnetic composite material.

The invention relates to a speaker (1) comprising a coil arrangement (2) with at least two voice coils (3a, 3b), a magnet system (4) and a membrane (10) being fixed to the coil arrangement (2) and the magnet system (4). The membrane (10) has a first compliance (c.sub.1) and together with the coil arrangement (2) causes a first resonance frequency (fres.sub.1) for an oscillation of the membrane (10). In addition, the speaker (1) comprises a second connector (14, 17, 17a, 17b, 24, 25a, 25b) with a second compliance (c.sub.2), which interconnects the voice coils (3a, 3b). The second connector (14, 17, 17a, 17b, 24, 25a, 25b) together with the voice coils (3a, 3b) causes a higher second resonance frequency (fres.sub.2) for the oscillation of the membrane (10). Moreover, the invention relates to an electronic sound signal circuit (18), which is designed to output coil signals (SO1, SO2) having a frequency dependent phase shift (). In addition, invention relates to a sound system comprising an electronic sound signal circuit and a speaker of the above kind and to a method for manufacturing a coil arrangement (2).

A speaker includes: a vibrating body including a diaphragm and an edge; a coil directly or indirectly attached to the diaphragm; a pair of lead wires electrically connected to the coil; a yoke; a frame which supports the diaphragm via the edge and in which a magnetic circuit is housed; and an inner terminal to which the lead wire is connected. A passage through which the lead wire passes is disposed between the coil and the inner terminal.

A loudspeaker includes two diaphragms arranged opposite each other, a drive unit for deflecting the two diaphragms in response to a control signal, the drive unit being coupled to the two diaphragms such that a first one of the two diaphragms is deflected in a first direction, and a second one of the two diaphragms is deflected in a second direction equal to the first direction.

Disclosed is a sound producing device, including a magnetic circuit system and a vibration system. The magnetic circuit system includes a primary magnet steel and a secondary magnet steel with a magnetic gap therebetween, wherein the secondary magnet steel includes a body portion and a protruding portion protruding in a direction toward the primary magnet steel from the body portion, and wherein the primary magnet steel has a primary magnetic conductive plate disposed thereon. The vibration system includes a diaphragm and an voice coil wound by wire, wherein the voice coil is inserted in the magnetic gap to drive the diaphragm to vibrate, and wherein a number of layers of wire winding at an end of the voice coil away from the diaphragm are less than that of layers of wire winding at another end of the voice coil contacting with the diaphragm, to form a notch.

Disclosed is a loudspeaker structure including a housing, a magnetic element, a conductive ring and a first vibration assembly. The housing has an accommodation groove and a first sound cavity, the accommodation groove communicates with the first sound cavity, and the first sound cavity has a first opening. The magnetic element is disposed in the accommodation groove. The conductive ring is wound around a peripheral side of the magnetic element, and a current in the conductive ring controls a magnetic field of the magnetic element. The first vibration assembly has a first diaphragm and a first vibration element, the first diaphragm covers the first opening, the first vibration element is disposed on the first diaphragm, and the first vibration element is attracted or repelled by the magnetic field of the magnetic element to drive the first diaphragm to vibrate to produce sound.

The present application provides a speaker including a basket frame, a magnetic circuit system and a vibration system. The magnetic circuit system includes a magnetic bowl, a main magnetic steel, and a sub-magnetic steel spaced apart from the main magnetic steel, with a magnetic gap formed in the space between the main magnetic steel and the sub-magnetic steel. The vibration system includes a diaphragm, and configured to drive the diaphragm to vibrate. The voice coil includes a first main body and a first projecting portion. The sub-magnetic steel includes a second main body and a second projecting portion. The first projecting portion and the second projecting portion are arranged staggeredly in the magnetic gap. The sub-magnetic steel is provided with localized projecting portions within the magnetic gap to reduce the localized magnetic gap to increase the driving force of the speaker and provide a greater output sensitivity.