An acoustic conversion device for an active noise control is provided. The acoustic conversion device can effectively suppress or remove noise by controlling variation in a lowest resonance frequency. A volume of a closed space is smaller than an equivalent compliance air volume of a speaker unit. Therefore, motion of a vibration plate, an edge and a damper is suppressed, it is possible to restrain the edge and the damper from being deteriorated with time, variation in lowest resonance frequency can be suppressed, phase of emitted sound can be less prone to be deviated from opposite phase of noise, and it is possible to effectively suppress or remove noise.

A method of calibrating an earphone may include: securing an ANC earphone to a calibration fixture, the calibration fixture including an ear model configured to support the ANC earphone, the ear model having an ear canal configured to anatomically resemble a human ear canal and a concha configured to anatomically resemble a human ear concha, the ear canal extending from the concha to an inner end of the ear canal; generating, with the ANC earphone, an audio signal based on a reference tone; determining a characteristic of the audio signal; comparing the characteristic of the audio signal to a previously determined reference characteristic; and adjusting a gain value of the ANC earphone based on the comparing. Additional methods and apparatus are also disclosed.

A method for noise cancellation. The method includes providing a sound signal output device having a listening device output, a microphone input, and signal processing circuitry. The signal processing circuitry is adapted for causing the sound signal output device to perform in a noise-cancellation mode, including making available to the sound signal output device, at the microphone input, a noise-containing signal which is representative of ambient acoustical noise, deriving a noise-cancelling signal from the noise-containing signal, and making available to the personal listening device, at the listening device output, the noise-cancelling signal.

An active noise control apparatus for a vehicle including: a plurality of microphones each configured to receive noise generated in the vehicle and generate an electrical signal corresponding to the noise; an external amplifier configured to supply power required for operations of the plurality of microphones; and a head unit configured to control the external amplifier to output a signal for removing the noise, based on the electrical signals generated from the plurality of microphones.

The present invention relates to a broadband sound absorption device using area division, the device comprising: Helmholtz resonators including a neck portion and a cavity portion connected to the neck portion and having a predetermined area and thickness; and a unit sound absorber including at least one pair of the Helmholtz resonators, wherein a plurality of unit absorbers are arranged on a plane or curved surface, and the plurality of sound unit absorbers are formed to have cavity portions with different areas to minimize the thickness while enabling sound absorption for a wider band.

A sound absorbing device according to an exemplary embodiment of the present invention comprises a plurality of sound absorbing cells arranged adjacent to each other on a plane, and each of the plurality of sound absorbing cells includes: a chamber having a volume therein, and in which a plurality of micro holes is perforated on a front surface in which a sound wave is incident; and a neck part introduced and extended to a rear of the front surface and penetrated by a through hole for communicating the outside and the chamber.

Disclosed are a noise control method and apparatus, a chip, and a vehicle. The method includes: acquiring at least one first reference acoustic signal and at least one error acoustic signal that correspond to a first noise reduction cycle; transmitting the at least one first reference acoustic signal and the at least one error acoustic signal to a second processing unit; updating filter parameters based on the at least one first reference acoustic signal and the at least one error acoustic signal to obtain first filter parameters, and returning the same to the first processing unit; and performing, based on the first filter parameters, filtering processing on at least one second reference acoustic signal corresponding to a second noise reduction cycle to obtain at least one noise control signal, and correspondingly transmitting the same to at least one sound source corresponding to the at least one second position.

A vibration reduction unit and a transformer comprising same are disclosed. A vibration reduction unit according to one aspect of the present invention comprises: a rod part connected to the outside and extending in one direction; and a mass part coupled to the rod part so as to reduce vibration transmitted to the rod part, wherein the mass part may comprise: a mass member formed to have a predetermined mass; and a mass hollow formed to penetrate the inside of the mass member and to which the rod part is coupled.