This application relates to audio driving circuitry (100), and in particular to audio driving circuitry for outputting first and second audio driving signals for driving a stereo audio load (106), which may be a stereo audio load of an accessory apparatus (102) removably coupled to the audio driving circuitry in use. A load monitor (111) is provided for monitoring to monitor, from a monitoring node (112), an indication of a common mode return current passing through a common return path, together with an indication of a common mode component of the first and second audio driving signals and to determine an impedance characteristic of the stereo audio load. The load monitor (111) can provide dynamic monitoring of any significant change in load impedance. In some embodiments the load monitor (111) comprises an adaptive filter (301) which adapts a parameter of the filter which is related to the load impedance so as to determine the indication of load impedance.

One or more accelerometers embedded with an earbud and/or a set of earphones are able to sense a moving pace of a user. Based on a moving pace of the user, a signal is sent to a remotely connected electronic device. The electronic device is able to separately increase and decrease a beat or rhythm of the audio from the electronic device based on a pace of the user. In some embodiments, an audio alert is sent to the user to inform the user of pace and whether the user has increased or decreased their pace. Additionally, in some embodiments, a program stored on the electronic device is used to compare the user's current progress and/or speed based on past runs and workouts.

The invention relates to a method and apparatus for recognizing a digital audio signal in a system, in which at least some of the electronic components are at times in sleep or unenergized mode, in which method the digital audio signal is amplified and recognized, the amplified signal is decoded in a decoding circuit, the decoded signal is led to a signal processor for further processing and digital/analog conversion, and an audio signal is created from the analog signal. According to the invention, the amplified, undecoded signal is led directly to the signal- or microprocessor to be used and recognized, and the circuit implementing the decoder is kept in sleep mode unless a digital audio signal has been recognized.

Systems, methods, and non-transitory computer-readable storage media for performing a role swapping operation between a pair of non-tethered wireless ear buds after detecting a triggering event. Further, state information can be coordinated between devices, including in connection with performing a role swap between buds in a pair of wireless, untethered ear buds, where one wireless ear bud is in a primary role and is responsible for a connection with a companion device, and another wireless ear bud in the pair is in a secondary role.

An audio reproduction device, a system, and a method for allowing a first user, who is listening to a first audio signal though a first headset, is provided to invite a second user, who is listening to a second audio signal through a second headset, to quickly start listening to the first audio signal. To this purpose, the first headset sends a signalling message to the second headset and relays the first audio signal to it. Both the audio signals emitted by the audio sources and that relayed by the first headset may be transmitted by means of a Bluetooth technology enabling a device both to receive a Bluetooth signal as a slave in a piconet and to transmit a corresponding Bluetooth signal as a master in another piconet.

A method of wirelessly synchronizing a plurality of discrete electronic devices each having an audio input channel and audio output channel. The method comprises detecting an output injection parameter of the audio output channel of a first electronic device at the time when an audio signal is output by the audio output channel of the first electronic device; detecting an input injection parameter of the audio input channel of a first electronic device at the time when the audio signal is injected to the audio input channel of the first device; receiving an input injection parameter of the audio input channel of a second device; receiving an output injection parameter of the audio output channel of a second device; and determine a synchronization parameter for synchronizing the first electronic device and the second electronic device on the basis of the detected parameters and the receiving parameters of audio channels.

Fault detection techniques for control of sensor systems. A sensor control integrated circuit (“IC”) may include a fault detection system for coupling to the sensor supply lines. The system may detect faults for each of the sensor supply lines. The fault detection system may level shift sensor supply line signals from a first voltage domain to a second voltage domain appropriate for the fault detection system of the controller IC. The fault detection system may level shift source potential voltages from the first voltage domain to the second voltage domain to detect predetermined fault types. The fault detection system may compare the second domain voltages from the sensor supply lines to voltages representing predetermined fault types and may generate fault status indicators based on the comparison.

Example techniques relate to changing a playback device mode based on a device base. In an example implementation, a first playback device operates in a first mode where it is connected to a first network and plays back audio content while in the first mode. The playback device detects connection of the first playback device to a device base and while the first playback device is on the device base, detects connection to a second network. The first playback device switches from operating in the first mode to operating in a second mode. The first playback device forms a stereo pair configuration with a second playback device over the second network in the second mode. While in the second mode, the first playback device plays back a first channel of audio content in synchrony with the second playback device playing back a second channel of the audio content.

An audio jack may include two contacts to electrically connect to a ground contact of an audio plug in order to detect that a metallic audio plug is inserted into the audio jack. A first of these two contacts may be grounded to form a current return path that generates a ground voltage at the ground contact of the audio plug. The second of these two contacts may be repurposed after the detection to sense the ground voltage. The sensed ground voltage may be added to right and left audio signals. The net voltages provided to the audio plug may be right and left audio signals that include the sensed ground voltage minus the actual ground voltage at the ground contact of the audio plug. This may remove the ground voltage from the net audio output signals, which may reduce crosstalk.

A transmission method, applied to a mobile terminal provided with a headset interface, is disclosed, where the method includes determining a type of a headset connected to the headset interface. If the headset is a multi-channel headset, an audio digital signal is transmitted to the headset using the headset interface. If the headset is not a multi-channel headset, an audio analog signal is transmitted to the headset using the headset interface. Further disclosed are a mobile terminal, a multi-channel headset, and an audio play system.