One embodiment of the invention discloses an acoustic device having a housing including a receiving space and a sound hole communicating with the receiving space; a vibration unit received in the receiving space; a magnetic circuit unit driving the vibration unit to vibrate; wherein, the vibration unit includes a first part away from the sound hole and a second part close to the sound hole; and the first part is driven by a higher magnetic force generated by the magnetic circuit unit than the second part.

The present invention provides an electromagnetic signal converter for an osteophone, comprising a soft magnetic yoke, an electrical coil arranged concentrically to the longitudinal axis of the yoke, an elastically suspended, soft-magnetic armature which, viewed in the direction of the longitudinal axis of the yoke, is separated from the yoke by a working air gap and can move along the longitudinal axis of the yoke, and a permanent magnet which is magnetized in the direction of the longitudinal axis of the yoke in order to generate a magnetic biasing voltage of the yoke and of the armature, characterized in that the permanent magnet and the coil do not overlap one another in the direction of the longitudinal axis of the yoke and that means is provided for dividing the magnetic flux that can be produced by the coil onto at least two flux paths, wherein one flux path runs outside of the permanent magnet, and characterized in that the permanent magnet, yoke and coil are surrounded in the signal converter of the invention by a soft magnetic housing which is separated by an air gap from the armature and from the yoke so that the magnetic flux which can be generated by the coil can be guided by the soft magnetic housing onto a flux path outside of the permanent magnet.

Several embodiments of the instant invention incorporate a loudspeaker design utilizing hard magnetic poles and yokes. The magnetic field of the loudspeaker is created and guided with a series of critically formed hard magnetic structures guiding the magnetic field from the primary magnet to the gap in a loop of hard magnetic material, replacing the soft magnetic materials normally used. Magnetization of the components of the hard magnetic loudspeaker driver with radial pole patternsa yoke radial magnet, a washer pole magnet and a yoke upper ring magnetis performed with these components in their final assembly relationships.

A magnetic sheet having a magnetic material particle comprising a hexaferrite and a nanofiber matrix made of two or more nanofibers, wherein the magnetic material particle is dispersed in the nanofiber matrix. A manufacturing method thereof and a speaker including the magnetic sheet are also provided.

An electro-acoustic device is provided, including a frame; a magnetic circuit received in the frame and including a lower plate fixed on a bottom of the frame and a magnet attached on the lower plate; a vibration system received in the frame and including a vibrating diaphragm attached to a top of the frame; a cavity formed cooperatively by the lower plate, the frame and the vibrating diaphragm; a leak hole provided between the frame and the lower plate for communicating with outside of the electro-acoustic device; and a damper attached to the lower plate and located inside of the electro-acoustic device for covering the leak hole internally.

An electromechanical transducer including a magnetic circuit having a magnet configured to generate a magnetic field and a magnetic gap into which a voice coil associated with a diaphragm is at least partially inserted, the magnetic field having a primary flux component and a secondary flux component. The transducer further including a housing positioned around the magnetic circuit, the housing having an acoustic spout whose sound outlet opening is positioned outside of a portion of the magnetic field that is dominated by the primary flux component. A transducer including an enclosure having a top wall, a bottom wall, at least one side wall connecting the top wall to the bottom wall and an acoustic spout extending from the top wall or the bottom wall, a diaphragm, a voice coil and a magnet assembly having a ring magnet and a gap within which the voice coil is positioned.

An apparatus including a frame; a coil movably connected to the frame; and a magnet system connected to the frame. The magnet system includes at least one magnet and at least one pole piece connected to the at least one magnet. The at least one pole piece include a magnet pot. A cross sectional length of the magnet pot and the frame are substantially the same in at least one cross sectional location.

A speaker is provided in the present disclosure. The speaker includes a magnetic circuit system for providing magnetic field, a diaphragm, a suspension, a drive mechanism and a horizontal former, which is retained on the surface of the diaphragm directly facing the magnetic circuit system. The diaphragm is suspended above the magnetic circuit system for generating sound by vibrating. The suspension is used to suspend the diaphragm above the magnetic circuit system. The drive mechanism is disposed under the diaphragm and can interact with the magnetic circuit system so as to drive the diaphragm to vibrate in order to generate sound. The horizontal former is retained on the surface of the diaphragm directly facing the magnetic circuit system, wherein the horizontal former is provided with a communication space which communicates the space under the diaphragm and the space under the suspension.

A speaker is provided in the present disclosure. The speaker includes a magnetic circuit system, a vibration system and an auxiliary system suspending the vibration system above the magnetic circuit system. The magnetic circuit system comprises a yoke, permanent magnets assembled on the yoke, and a magnetic gap near the permanent magnets. The yoke comprises an upper surface for assembling the permanent magnets, a lower surface opposite to the upper surface, side surfaces connecting the upper surface and the lower surface, and communication conduits extending through the upper surface and the side surface to communicate the magnetic gap and the space outside the speaker.

A planar dynamic sound transducer comprising a planar diaphragm having at least one electrical conductor, and a planar magnet arrangement having a first portion, a second portion, and an edge region. The second portion surrounds the first portion and extends between the first portion and the edge region of the magnet arrangement. The first portion contains a first plurality of openings so that the first portion has a first degree of opening. The second portion contains a second plurality of openings so that the second portion has a second degree of opening. The first degree of opening is greater than the second degree of opening.