A variable impedance speaker apparatus comprising multiple, selectable impedances and multiple voice coil wires. In some embodiments, the speaker provides three to four different impedances which can be easily selected by inserting a jumper into the desired coil arrangement to configure the voice coil accordingly. In further embodiments, the speaker apparatus comprises multiple voice coil wires wherein each voice coil wire is wound about a voice coil at the same time.

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 linear motor magnet assembly for use in a loudspeaker unit, with a fixed base actuator component and a membrane actuating element, the membrane actuating element having a linear excursion axis. A first auxiliary magnetic element and a second auxiliary magnetic element are present, the first auxiliary magnetic element providing a first auxiliary spatial magnetic field with a major axis aligned with the linear excursion axis. The second auxiliary magnetic element is fixedly connected to the membrane actuating element of the linear motor magnet assembly and has a second auxiliary spatial magnetic field, the second auxiliary magnetic field overlapping the first auxiliary spatial magnetic field and being substantially similarly oriented as the first auxiliary spatial magnetic field over a first predetermined excursion range of the linear motor magnet assembly.

A voice coil driving system includes a magnetic circuit, a voice coil and a driving circuit, and the voice coil is suspended in the air gap and includes a plurality of voice coil sections. A method of driving a voice coil performed by the driving circuit comprises: receiving an audio signal; determining whether the audio signal belongs to a first class signal or a second class signal; when determining that the audio signal belongs to the first class signal, selecting a target voice coil section from the voice coil sections according to the excursion of the voice coil and generating and transmitting a first driving signal to the target voice coil section according to the first class signal; when determining that the audio signal belongs to the second class signal, generating and transmitting second driving signals to the voice coil sections according to the second class signal.

Aspects of the subject technology relate to stiffness reduction for audio transducers, such as speakers. Stiffness reduction can be provided using one or more magnetic structures configured to move with a voice coil and/or a diaphragm of the speaker, and assist in the motion of the voice coil and/or diaphragm via magnetic interaction with one or more magnets of the speaker. In one or more implementations, the one or more magnetic structures may form a tri-stable system with the one or more magnets.

An acoustic system provided with a speaker includes a displacement detector, and a drive unit, wherein the speaker includes a first magnetic gap, a second magnetic gap, and voice coils, wherein the first magnetic gap propagates magnetic flux in one of radial directions of the speaker, the second magnetic gap propagates magnetic flux in another of the radial directions of the speaker, a space between the first magnetic gap and the second magnetic gap in the axial direction is larger than a winding width of each of the voice coils, the vibration system vibrates between a position where at least a portion of the voice coils is positioned within the first magnetic gap and a position where at least a portion of the voice coils is positioned within the second magnetic gap, and the drive unit drives each of the voice coils using the audio signal as a drive signal.

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.

Provided is a loudspeaker. The loudspeaker includes a shell, a vibration structure, a magnetic circuit structure and a voice coil. The shell includes a main shell, an inner support body and an elastic member. The inner support body is connected to the main shell body through the elastic member, multiple inner support bodies are provided, and the multiple inner support bodies are disposed in a surrounding manner to define an inner support cavity that penetrates in a first direction. The vibration structure is connected to the main shell. The magnetic circuit structure is located in the inner support cavity and is sandwiched between the multiple the inner support bodies. The voice coil includes a main voice coil and an auxiliary voice coil.

Aspects of the subject technology relate to stiffness reduction for audio transducers, such as speakers. Stiffness reduction can be provided using one or more magnetic structures configured to move with a voice coil and/or a diaphragm of the speaker, and assist in the motion of the voice coil and/or diaphragm via magnetic interaction with one or more magnets of the speaker. In one or more implementations, the one or more magnetic structures may form a tri-stable system with the one or more magnets.