Systems, methods, and apparatus are provided for recording high output power levels of sound at low sound pressure levels. For example, an apparatus comprises an enclosure, a speaker disposed within the enclosure, a microphone disposed within the enclosure, and an evacuation port. The evacuation port is configured to connect to a system that reduces a pressure level within the enclosure to a level that is less than an ambient air pressure level outside the enclosure. The enclosure is sealed or otherwise configured to provide a sealed enclosure, to maintain the reduced air pressure within the enclosure. The speaker can be driven by an amplifier at high output power levels to generate a distorted sound of an amplified electric musical instrument for recording purposes, while the reduced pressure level within the enclosure serves to attenuate the sound pressure level and perceived loudness which emanates from the speaker.

Provided is a speaker, including a holder, a vibration unit, and a magnetic circuit unit. The vibration unit includes a first diaphragm and a voice coil, and the voice coil includes a voice coil lead wire. A centering support is sandwiched between the first diaphragm and the voice coil, and includes a first pad portion. The magnetic circuit unit has a recessed portion formed at a position corresponding to the first pad portion. In the speaker provided by the present disclosure, the magnetic circuit unit is provided with the recessed portion to increase the distance between the magnetic circuit unit and the first pads, so that the vibration amplitude of the voice coil can be increased, thereby improving the acoustic performance of the speaker, and providing operating space for the subsequent welding process.

A diagnostic method of electrical equipment which includes a processing unit, an internal microphone, and electrical components other than microphones or speakers, the diagnostic method including the steps of acquiring a received audio signal produced from an ambient sound signal, by the at least one internal microphone or by the at least one external microphone, producing monitoring parameters from the received audio signal, which are representative of an interfering sound signal comprised in the ambient sound signal and emitted by at least one of the electrical components, and detecting a sound anomaly resulting from a failure of at least one electrical component of the electrical equipment from the monitoring parameters.

Audio circuitry, comprising: a speaker driver operable to drive a speaker based on a speaker signal; a current monitoring unit operable to monitor a speaker current flowing through the speaker and generate a monitor signal indicative of that current; and a microphone signal generator operable, when external sound is incident on the speaker, to generate a microphone signal representative of the external sound based on the monitor signal and the speaker signal.

A method for driving a voice coil of a loudspeaker may include providing a magnetic circuit having an air gap, providing a voice coil suspended in the air gap, and applying an audio signal to the voice coil to move it along a travelling axis. The voice coil comprises a main voice coil section, and a pair of auxiliary voice coil sections arranged along the travelling axis with auxiliary voice coil sections arranged respectively on either side of the main voice coil section. Applying an audio signal comprises continuously coupling a main driving signal based on the audio signal to the main voice coil and selectively coupling an auxiliary driving signal based on the audio signal to the pair of auxiliary voice coil sections. The disclosed embodiments further relate to a voice coil driving system and a loudspeaker comprising a voice coil driving system.

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.

A system manages temperature and excursion effects on a loudspeaker. Data corresponding to a temperature of the loudspeaker and data corresponding to an excursion (i.e., displacement) of a membrane of the loudspeaker are determined. The dynamic ranges of the temperature and excursion data are compressed, combined, and smoothed. This smoothed data is multiplied with a delayed version of audio data; peak values of the result may be limited. This operation may be performed on multiple frequency bands of audio data. The final output data is combined to form a full-band signal and sent to a loudspeaker.

An audio processing system is described including an amplifier configured to receive a first audio signal and output the first audio signal to an acoustic transducer comprising a voice coil. A sensor detects a signal corresponding to voice coil current of the acoustic transducer. A controller compares the first audio signal and the detected signal and determines a second audio signal from the comparison. The second audio signal is representative of an external sound source detected via the acoustic transducer. The audio processing system may simultaneously output the first audio signal and receive the second audio signal using the same acoustic transducer.

A vehicle is provided and includes a first tire, a second tire, and a detector that is configured to detect an air pressure of the first tire. A vibration generator is configured to generate vibration in the second tire. A controller is configured to operate the vibration generator to cause the second tire vibrate when the air pressure of the first tire satisfies a predetermined normal condition.

A speaker system includes a speaker configured to output sound from an electric signal, a sensing unit configured to measure at least one of current or a voltage of the speaker, an amplifier configured to supply current to the speaker, and a control unit configured to measure inductance of the speaker on the basis of the at least one of the current or the voltage of the speaker, to determine a current temperature on the basis of the inductance, and to adjust current to be applied to the speaker by the amplifier on the basis of the current temperature such that a variation in output of the speaker with respect to a temperature is compensated for.