An apparatus and method for determining signals representative of events in the environment of a reactive transducer while being driven by a switching amplifier is disclosed. While the switching amplifier is in a zero voltage state, a signal capture circuit that is also in a zero voltage state is connected to the transducer for a relatively brief period of time during which a measurement is made of the residual current flow due to the inductance of the transducer. A prediction of the output signal is then subtracted from the signal measured across the transducer, reducing the overall range of the signal and increasing the relative size of the back-EMF signal compared to any remaining output signal. If desired, conventional echo cancellation can then be performed. The back-EMF signal can then be subjected to further processing by an analog-to-digital converter as known in the art.

The present application discloses playback devices and networks, software for operating playback devices and playback device networks, and methods of operating playback devices and networks, where an individual network device is configured to switch between operating various operating modes comprising a non-paired mode and a paired mode, where the playback device is configured to output various channels of audio content within various audio frequency ranges while operating in the various operating modes.

A technique for producing audio includes providing multiple audio tracks of respective sound sources of an audio performance and rendering a sound production of the audio performance at a listening venue by playing back the audio tracks on respective playback units.

An acoustic system includes: a first terminal device including a first-terminal sound emitting unit, an earhole sound collecting unit configured to collect earhole echo sound, and a first-terminal control unit configured to perform authentication between the first terminal device and a user based on the echo sound collected by the earhole sound collecting unit; an onboard device including an onboard-device sound emitting unit and an onboard-device control unit configured to perform authentication between the onboard device and the user based on communication with the first terminal device; and a second terminal device includes a second-terminal control unit configured to set a destination of sound data to one of the first terminal device and the onboard device when the onboard-device control unit detects that a predetermined condition including a condition that the user has been authenticated is satisfied.

Disclosed are a communication control method, apparatus and system, and a charging case and a wireless earphone. The method includes: acquiring, when a charging case is connected with a first wireless earphone though a first power supply pin and a second power supply pin, first to-be-transmitted data if the charging case is to communicate with the first wireless earphone; and controlling a first single-pole double-throw switch to connect the first power supply pin with a first TxRx and level conversion circuit, sequentially transmitting a predetermined start code and the first to-be-transmitted data to the first wireless earphone through the first power supply pin, where the first wireless earphone controls a first predetermined charging pin to be connected with a second TxRx and level conversion circuit based on the predetermined start code, and receives the first to-be-transmitted data.

A method of converting an audio signal into signals for a number of loudspeaker transducers, where the audio signal is divided up into audio sub signals each representing a particular frequency interval, and where the signal for each loudspeaker transducer comprises a portion of each audio sub signal which varies over time.

This application relates to earbuds configured with one or more biometric sensors. At least one of the biometric sensors is configured to be pressed up against a portion of the tragus for making biometric measurements. In some embodiments, the housing of the earbud can be symmetric so that the earbud can be worn interchangeably in either a left or a right ear of a user. In such an embodiment, the earbud can include a sensor and circuitry configured to determine and alter operation of the earbud in accordance to which ear the earbud is determined to be sitting in.

A method and an apparatus for audio signal processing selection are provided. In the method, multiple audio signal processing operations are performed on a synthesized audio signal to generate multiple processed audio signals, the audio signal processing operations are evaluated according to the comparison results between the processed audio signals and the primary signal, and the audio signal processing operation corresponding to a designated application and the designated audio output mode is selected according to the evaluation result of the audio signal processing operations. The synthesized audio signal is generated by adding a secondary signal into a primary signal. The signal processing is related to remove the secondary signal from the synthesized audio signal. Those processed audio signals are used by the designated application at the designated audio output mode. The comparison result is related to signal similarity. The evaluation result is related to the highest signal similarity.

An electronic device may comprise audio processing circuitry and a universal serial bus (USB) connector having a first contact and a second contact. In a first mode of operation, the audio processing circuitry is configured to output one or more audio signals carrying music and/or voice via the first contact and the second contact. In a second mode of operation, the audio processing circuitry is configured to output a signal for delivering supply current via the first contact and the second contact. While the electronic device is in the first mode of operation, a gain and/or volume limit of the audio processing circuitry may be set to a first level, and while the electronic device is in the second mode of operation, the gain and/or volume limit of the audio processing circuitry may be set to a second level that is higher than the first level.

A BLUETOOTH connection method includes an electronic device establishing basic rate (BR)/enhanced data rate (EDR) connection to an accessory device. The electronic device determines that the electronic device supports a dual-mode connection and that the accessory device also supports the dual-mode connection. The dual-mode connection includes the BR/EDR connection and a BLUETOOTH Low Energy (BLE) connection. The electronic device disconnects the BR/EDR connection to the accessory device, and establishes the BLE connection to the accessory device.