A coil assembly is coupled to a diaphragm. The coil assembly has a number of coils that are fixed in a stacked, end to end manner along a length axis. The coils include a middle coil, a several upper coils and several lower coils. Each coil has a respective pair of coil terminals so that it can be independently driven by an audio signal. The coil assembly as a whole is overhung, while each of constituent coils is underhung so that there are at least two adjacent coils that are completely within the magnetic gap, and at least two other coils that are completely outside the magnetic gap, during a majority of the full excursion of the coil assembly. Other embodiments are also described and claimed.

A transducer assembly comprising: a magnet motor assembly comprising a first magnet plate and a second magnet plate arranged along an axis, a first support plate positioned between inward facing surfaces of the first magnet plate and the second magnet plate, a second support plate positioned along an outward facing surface of the first magnet plate to form a first magnetic gap between the first support plate and the second support plate, and a third support plate positioned along an outward facing surface of the second magnet plate to form a second magnetic gap between the first support plate and the third support plate; a voice coil coupled to the magnet motor assembly, wherein the voice coil is positioned around the first support plate and within the first magnetic gap and the second magnetic gap; and a piston coupled to the voice coil, wherein the piston is operable to vibrate in a direction parallel to the axis.

This electroacoustic conversion chain comprising at least one loudspeaker, this loudspeaker comprising means for generating a magnetic field in a magnetic circuit having an air gap and a membrane secured to turns of a conducting material which may move in this air gap, is characterized in that it comprises at least one control module comprising at least one input for conveying a signal to be broadcast and at least one output connected to a turn, the control module being able to apply to said or each output an excitation signal depending on the position of at least one turn relatively to the air gap.

Disclosed are a multilayer voice coil plate capable of significantly reducing difficulties in designing and manufacturing a multilayer voice coil pattern, and a flat speaker including the same. The multilayer voice coil plate may include: a first-type voice coil pattern layer formed in the shape of a track and connected from a first outer via hole outside the track to an inner via hole disposed in the track; and a second-type voice coil pattern layer formed in the shape of a track and connected from a second outer via hole outside the track to an inner via hole disposed in the track. The plurality of first-type voice coil pattern layers and the plurality of second-type voice coil pattern layers may be stacked so as to be insulated from each other, and the first outer via holes, the second outer via holes and the inner via holes may be electrically connected through interlayer conductors, respectively.

Two coils are wrapped in one of numerous different implementations. In one implementation, the two coils are wrapped about a portion of a bobbin that has at least three flanges. The first coil is disposed about a first portion of the bobbin between the first flange and the second flange, and a second coil is disposed about a second portion of the bobbin between the second flange and the third flange.

A method for avoiding an offset of a membrane (3) of an electrodynamic acoustic transducer (1) having two voice coils (7, 8) is presented, wherein a control voltage (U.sub.CTRL) is applied to at least one of the voice coils (7, 8) until the electromotive force (U.sub.emf1) of the first coil (7) or a parameter derived thereof and the electromotive force (U.sub.emf2) of the second coil (8) or a parameter derived thereof substantially reach a predetermined relation. Furthermore, an electronic offset compensation circuit (12) is presented, which performs the above application of a control voltage (U.sub.CTRL). Finally, the invention relates to a transducer system with a transducer (1) and an electronic offset compensation circuit (12) connected to the transducer (1).

A transducer system, comprising an electrodynamic acoustic transducer (1) with a membrane (3), a plurality of voice coils (7, 8) electrically switched in series, and a magnet system (9, 10, 11) is presented, wherein just an outer tap/terminal (T2) of the serially connected voice coils (7, 8) is electrically connected to an audio output of an amplifier (17). Moreover, a method for feeding a sound signal to an electrodynamic acoustic transducer (1) is presented, wherein the voice coils (7, 8) are driven by an audio signal just via an outer tap/terminal (T2) of the serially connected voice coils (7, 8).

This application relates to the technical field of electronic devices, and provides a core, a speaker module, and an electronic device, to balance thinning and audio performance of the device. The core includes a diaphragm assembly, a first voice coil set, a second voice coil set, and a magnetic circuit system. The first voice coil set and the second voice coil set are fastened to the diaphragm assembly. The magnetic circuit system includes a magnet assembly. The magnet assembly includes a first central magnet, a second central magnet, and a side magnet. A magnetization direction of the second central magnet is the same as a magnetization direction of the first central magnet. The core provided in embodiments of this application is configured to convert an audio electrical signal into sound.

The invention provides a loudspeaker with a fin-reinforced voice coil structure, comprising a voice coil, fins, an upper magnetic conductor, and a magnetic conduction column, wherein a magnetic gap is formed between the upper magnetic conductor and the magnetic conduction column located in the center thereof; the voice coil works in the magnetic gap; wherein the inner wall of the voice coil is connected to the fins; wherein one end of each fin is connected and fixed to the inner wall of the voice coil; wherein the magnetic conduction column is provided with fin grooves for accommodating the other ends of the fins; wherein the width of the fin grooves is at least 0.2 mm greater than the thickness of the fins, so that the balance performance and the stability of the voice coil are greatly improved. The distortion is greatly reduced compared, by measurement, with the traditional voice coil.

A loudspeaker is provided with a magnet assembly with an overall length aligned along a longitudinal axis and a frame with a wall encircled around the magnet assembly with a length aligned along the longitudinal axis, wherein the magnet assembly and the wall define a voice coil gap. The loudspeaker is also provided with a voice coil disposed in the voice coil gap; wherein the magnet assembly is symmetrically aligned with the wall such that a halfway point of the overall length of the magnet assembly coincides with a midpoint of the length of the wall.