A method for determining a voice coil position of a voice coil includes providing a magnetic circuit having a magnetic gap and suspending the voice coil in the magnetic gap, applying a driving signal to the voice coil to produce an electromotive force, providing inductive sensors mechanically coupled to the voice coil, measuring inductive sensor signals based on outputs from the inductive sensors, processing the measured inductive sensor signals by determining at least one inductive sensor signal ratio, and determining a representation of the voice coil position based on the at least one inductive sensor signal ratio. A voice coil system, which can be incorporated in a loudspeaker, is configured to carry out the method.

In at least one embodiment, an audio system for extracting online parameters is provided. The system includes a loudspeaker and at least controller. The loudspeaker transmits an audio signal in a listening environment. The at least one controller includes a signal processing block and an adaptive filter. The signal processing block is programmed to provide a driving signal u(n) to drive the loudspeaker to transmit the audio signal. The adaptive filter is programmed to receive the driving signal and to receive a first varying signal i(n) from the loudspeaker in response to the loudspeaker transmitting audio signal. The adaptive filter is further programmed to generate an admittance curve for the loudspeaker based at least on the driving signal and the first varying signal.

In at least one embodiment, an audio amplifier system is provided. The system includes a loudspeaker and an audio amplifier. The loudspeaker transmits an audio output into a listening environment. The audio amplifier is programmed to receive an audio input signal and to generate an excursion signal corresponding to a first excursion level of the voice coil based on the audio input signal. The audio amplifier is further programmed to limit the excursion signal to reach a maximum excursion level and to determine a target pressure for an enclosure of the loudspeaker based on the maximum excursion level. The audio amplifier is further programmed to generate a target current signal based at least on the target pressure and to convert the target current signal into a target voltage signal to a target driving signal to drive the voice coil to reach the maximum excursion level.

A method of regulating power supply to a speaker and a system for regulating power supply to a speaker comprising a generating of a low frequency signal output to the speaker, sensing a current and a voltage of the speaker after the low frequency signal is output to the speaker, measuring an impedance of the speaker based on the current and voltage, determining a temperature of the speaker and comparing with a threshold value, and lowering a power supply to the speaker where the temperature is above the threshold value.

A bone conduction speaker is provided herein. The bone conduction speaker may include a magnetic circuit component for providing a magnetic field, a vibration component located in the magnetic field, and a case. At least a part of the vibration component may convert an electrical signal into a mechanical vibration signal. The case may include a case panel facing a human body side and a case back opposite to the case panel, and accommodate the vibration component that causes the case panel and the case back to vibrate. A vibration of the case panel may have a first phase, and a vibration of the case back may have a second phase. When frequencies of the vibration of the case panel and the case back are within 2000 Hz to 3000 Hz, an absolute value of a difference between the first and the second phase(s) may be less than 60 degrees.

A method and system for calibrating an integrated volume acceleration sensor of a loudspeaker, wherein the method includes driving the loudspeaker with a calibration signal and meanwhile generating a sensor output signal by the integrated volume acceleration sensor measuring a volume acceleration over time of a motion element fixed to a moving part of the loudspeaker and/or of the moving part while the loudspeaker is driven with the calibration signal as well as generating a reference output signal by a reference sensor measuring the volume acceleration over time of the motion element and/or of the moving part of the loudspeaker while the loudspeaker is driven with the calibration signal, and additionally includes calculating a calibration value for the integrated volume acceleration sensor based on a ratio of the sensor output signal and the reference output signal and based on a predetermined reference calibration value of the reference sensor.

An electronic device includes a memory, a housing, an acoustic module comprising a coil and an acoustic membrane configured to be movable based on a signal applied to the coil, the acoustic module being disposed in an internal space of the housing, an amplifier, and a processor. The memory may store instructions that when executed by the processor cause the processor to apply a first signal to the coil through the amplifier to move the acoustic membrane in a first direction by a first distance and applying a second signal to the coil through the amplifier to move the acoustic membrane in a second direction different from the first direction and/or to move the acoustic membrane by a second distance different from the first distance after applying the first signal to the coil.

A position sensor may include a resonator attachable to a first object, and an antenna attachable to a second object and driven at a resonant frequency of the resonator. A change in a position of the first object relative to the second object may be sensed as a change in a power of the antenna when the antenna is driven at the resonant frequency of the resonator. The first object may be a former of a speaker, and a voice coil of the speaker may be positioned on the former together with the position sensor. In operation, the antenna may output a position signal to an external system of electronics, indicating a position of the voice coil. The external system of electronics may perform feedback processing to compensate for nonlinearities in the voice coil's position when the voice coil is used to drive a diaphragm of the speaker.

An audio output system for energizing a multiple voice coil transducer supplies at least two power output signals to the voice coils, a pilot tone generator for generating a pilot tone signal, and a power output circuit. The power output circuit generates power output signals from the pilot tone and the input signal so that the voice coils respond to the input signal with an in-phase electro-mechanical relationship and respond to the pilot tone with an out-of-phase (motion canceling) electro-mechanical relationship, reducing the effect of the pilot town on mechanical movement of the voice coil. A sensing circuit senses electrical signal values at terminals of the at least two voice coils, and a processing circuit detects a response of the output transducer to the pilot tone and determines at least one operating characteristic of the output transducer from the electrical signal values.

The present disclosure relates to a speaker device including a circuit housing, an ear hook, a rear hook, and a speaker assembly. The speaker assembly may include a headphone core and a housing for accommodating the headphone core, the housing may include a housing panel facing a human body and a housing back opposite to the housing panel, and the headphone core may cause the housing panel and the housing back to vibrate. An absolute value of a difference between a first phase of a vibration of the housing panel and a second phase of a vibration of the housing back may be less than 60 degrees when a frequency of each of the vibration of the housing panel and the vibration of the housing back is between 2000 Hz and 3000 Hz.