This application relates to circuitry for monitoring for instability of an amplifier. The amplifier (100) has a first signal path between an amplifier input (IN.sub.N) and an amplifier output (V.sub.OUT) and a feedback path from the output to form a feedback loop with at least part of the first signal path. A comparator (212) has a first input configured to receive a first signal (IN.sub.N) derived from a first amplifier node which is part of said feedback loop and a second input configured to receive a second signal (IN.sub.P) derived from a second amplifier node which varies with the signal at the amplifier input but does not form part of said feedback loop. The comparator is configured to compare the first signal to the second signal and generate a comparison signal (COMP), wherein in the event of amplifier instability the comparison signal comprises a characteristic indicative of amplifier instability.

A bone conduction earphone includes an earphone body configured to attach to an auricle of a human body and transmit an audio vibration signal and an ear hook configured to hook on the auricle. A first end of the ear hook is fixedly connected with the earphone body. A second end of the ear hook extends between the auricle and a head of the human body. The second end of the ear hook extends along the auricle and laterally deviates from the earphone body. In a natural state, a lateral distance between the earphone body and an extending end of the ear hook is less than a lateral distance from a front surface of the auricle to a back surface of the auricle. When the bone conduction earphone is worn, the earphone body and the ear hook clamp the auricle.

Examples of the disclosure relate to example systems and methods for operating wireless headset system for a vehicle. An example system includes a first wireless chipset to handle communication with a smartphone, and a second wireless chipset to handle communication with a headset. The example system also includes a processor configured to execute a first virtual machine to control the first wireless chipset and a second virtual machine to control the second wireless chipset.

An audio apparatus includes a network interface, a receiver, at least one storage, and at least one processor. The processor is configured to determine that the audio apparatus is in a state capable of communicating with the other audio apparatus via the network interface. The processor is also configured to receive audio data via the receiver transmitted from an external apparatus different from the other audio apparatus. The processor is also configured to output a sound based on the received audio data. The processor is also configured to transmit the sound emission control information stored in the at least one storage to the other audio apparatus. The sound emission control information includes one or more of a sound volume, and a frequency band.

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for wireless audio source switching. One of the methods includes receiving user input selecting a user interface control corresponding to one of a plurality of paired audio source devices with a wireless audio sink device that is a slave device of a first master/slave connection with a first paired audio source device of the plurality of paired audio source devices. The wireless audio sink device initiates a request to become a master device of a second master/slave connection with a second paired audio source device corresponding to the selected user interface control. The wireless audio sink device sends to the second paired audio source device a request to become a slave device of the second master/slave connection. The wireless audio sink device receives audio input from the second paired audio source device and outputs the received audio input.

A speaker system is provided having a primary speaker module configured to communicate with an external audio device and having a speaker output face and a back surface, and a secondary speaker module in signal communication with the primary speaker module and having a speaker output face and a back surface. The primary speaker module and the secondary speaker module combine in at least two configurations, a first configuration in which the primary speaker module and the secondary speaker module are connected at their back surfaces and their respective speaker output faces face opposite directions, and a second configuration in which the primary speaker module and the secondary speaker module are side by side and their respective speaker output faces face substantially the same direction.

Aspects of the present disclosure relate to power management techniques for reducing the power consumption of playback devices. Additionally, aspects of the present disclosure related to distributed processing techniques for processing audio across two or more processors.

A device can include a processor; memory accessible to the processor; a housing assembly that includes a display and a tray recess; and an ear bud tray disposed in the tray recess.

A host device configured to be wirelessly coupled to an accessory device, the host device comprising noise reduction circuitry, wherein, in use of the host device: a signal generated by a microphone of the accessory device in response to ambient noise is supplied to the noise reduction circuitry; the noise reduction circuitry applies a noise reduction transfer function to the signal supplied thereto to generate a noise cancellation signal; and the noise cancellation signal is supplied to at least one loudspeaker of the accessory device; and wherein the noise reduction transfer function applied by the noise reduction circuitry is user selectable or user adjustable.

An example implementation may involve a group of wearable playback devices including a first wearable playback device and a second wearable playback device. The wearable playback devices render multi-channel audio content according to particular playback responsibilities in the group. When a failure or other issue with the second wearable playback device occurs, the first playback device assumes at least part of the playback responsibility of the second playback device.