Abstract: A device and a method for nondestructively detecting a transient characteristic of a conductive screw of a turbo-generator rotor are provided. The device includes a personal computer (PC), an extremely-steep pulse generator, an ultra-high-frequency double-isolation transformer, and a pulse emitting and coupling module, which are connected in sequence. The pulse emitting and coupling module is connected to a load. A synchronous pulse receiving non-inductive divider circuit synchronously receives a characteristic waveform from the load, and the synchronous pulse receiving non-inductive divider circuit is connected to an ultra-high-speed analog/digital (A/D) module through a nonlinear saturation amplifying circuit that amplifies a signal. The PC receives a signal from the ultra-high-speed A/D module. The load includes a positive or negative excitation lead loop that is in a 180° symmetrical and instantaneous short-circuit state and a rotor shaft.

Abstract: The present disclosure relates to a magnetic circuit of a loudspeaker and a loudspeaker, which can improve the non-linearity of magnetic permeability, thereby reducing the distortion of the loudspeaker. A magnetic circuit comprises a T-yoke with a base and a columnar portion protruding upward from the base, a magnetic steel arranged on the base, and a front sheet arranged on the magnetic steel, wherein the magnetic steel and the front sheet are arranged around a periphery of the columnar portion, and a short-circuit ring is arranged on an inner side of the magnetic steel and/or the front sheet. A first short-circuit ring is provided between the inner wall of the magnetic steel and the outer wall of the columnar portion, and a second short-circuit ring is provided on the inner wall of the front sheet.

Abstract: A mid-range loudspeaker, including a frame, a diaphragm arranged on the frame, a magnetic circuit system arranged on the frame, and a voice coil connected to the diaphragm. The diaphragm includes a honeycomb plate having a front surface and a back surface. Covering films respectively cover the front surface and the back surface of the honeycomb plate. The honeycomb plate is provided with a plurality of holes.

Abstract: A loudspeaker system, having a good low-frequency response without a large box and effectively improving the efficiency of the loudspeaker system, so as to increase the output sound pressure level of the system, comprises a box and a plurality of loudspeakers arranged in the box and connected in parallel with each other, wherein each of the loudspeakers comprises a frame, a diaphragm arranged on the frame, and a voice coil for driving a vibration of the diaphragm; front surfaces of the diaphragms of the loudspeakers are arranged to face each other; a sound cavity is formed among the front surfaces of the diaphragms, and the sound cavity is in communication with the outside of the box; and each of the frames is located between a rear surface of its corresponding diaphragm and an inner wall of the box.

Abstract: Disclosed are a tweeter and an automobile audio system. The tweeter comprises: a bracket; a diaphragm comprising a top portion and an edge ring; a magnetic motor system; and a voice coil. A first cavity is formed between the top portion of the diaphragm, an inner wall of the voice coil, and the magnetic motor system. The bracket has an annular inner flange and an annular outer flange, the edge ring of the diaphragm is connected to the outer flange of the bracket, and the magnetic motor system is connected to the inner flange of the bracket, so that a second cavity is formed between the edge ring of the diaphragm, an outer wall of the voice coil, and the bracket. A through hole is opened on the voice coil, and the first cavity is in communication with the second cavity by the through hole.

Abstract: A loudspeaker system, having a good low-frequency response without a large box and effectively improving the efficiency of the loudspeaker system, so as to increase the output sound pressure level of the system, comprises a box and a plurality of loudspeakers arranged in the box and connected in parallel with each other, wherein each of the loudspeakers comprises a frame, a diaphragm arranged on the frame, and a voice coil for driving a vibration of the diaphragm; front surfaces of the diaphragms of the loudspeakers are arranged to face each other; a sound cavity is formed among the front surfaces of the diaphragms, and the sound cavity is in communication with the outside of the box; and each of the frames is located between a rear surface of its corresponding diaphragm and an inner wall of the box.

Abstract: The present disclosure relates to a magnetic circuit of a loudspeaker and a loudspeaker, which can improve the non-linearity of magnetic permeability, thereby reducing the distortion of the loudspeaker. A magnetic circuit comprises a T-yoke with a base and a columnar portion protruding upward from the base, a magnetic steel arranged on the base, and a front sheet arranged on the magnetic steel, wherein the magnetic steel and the front sheet are arranged around a periphery of the columnar portion, and a short-circuit ring is arranged on an inner side of the magnetic steel and/or the front sheet. A first short-circuit ring is provided between the inner wall of the magnetic steel and the outer wall of the columnar portion, and a second short-circuit ring is provided on the inner wall of the front sheet.

Abstract: Disclosed is a mid-range speaker. The operating range of the mid-range speaker can extend to 20 KHz, and the speaker has an improved high-frequency directivity. A mid-range speaker, comprising a basket, a diaphragm arranged on the basket, a magnetic circuit system arranged on the basket, and a voice coil connected to the diaphragm, wherein the diaphragm comprises a cellular board having a front face and a back face, and covering films respectively covering the front face and the back face of the cellular board; and the cellular board is provided with a plurality of holes.

Abstract: The present disclosure relates to a coaxial speaker, which has better dust-proof and water-proof performance. The coaxial loudspeaker comprises a bass unit and a high-pitched unit coaxially arranged, the bass unit comprises a T-iron, a diaphragm and a voice coil connected to the diaphragm. The coaxial loudspeaker further comprises a cabin fixed on the T-iron, a lower portion of the cabin passes through the voice coil to connect with the T-iron, a top end portion of the cabin is located above the diaphragm, the high-pitched unit is arranged on the top end portion of the cabin, and the coaxial loudspeaker further comprises a dust-proof ring having an upper edge connected with the top end portion of the cabin and a lower edge connected with the upper portion of the voice coil.

Abstract: The present disclosure relates to a coaxial speaker, which has better dust-proof and water-proof performance. The coaxial loudspeaker comprises a bass unit and a high-pitched unit coaxially arranged, the bass unit comprises a T-iron, a diaphragm and a voice coil connected to the diaphragm. The coaxial loudspeaker further comprises a cabin fixed on the T-iron, a lower portion of the cabin passes through the voice coil to connect with the T-iron, a top end portion of the cabin is located above the diaphragm, the high-pitched unit is arranged on the top end portion of the cabin, and the coaxial loudspeaker further comprises a dust-proof ring having an upper edge connected with the top end portion of the cabin and a lower edge connected with the upper portion of the voice coil.