A method of operating a headphone configured to be removed from and placed in close proximity to a user's ear can include generating an input signal by an input signal generating device. The method can also include determining whether an insertion event has occurred based on the generated input signal and causing the headphone to operate in 5 a low power mode responsive to an absence of an insertion event determination after a first period of time. The method can also include causing the headphone to operate in an ultra-low power mode responsive to the absence of an insertion event determination after a second period of time that occurs after the first period of time, the ultra-low power mode having a lower power consumption than the low power mode.

A method for reducing the power of an acoustic primary noise signal (d.sub.m(n)) at one or more control positions in a vehicle passenger compartment using an adaptive filter. The method comprising to compare a mean correlation coefficient (γ.sub.m(n)) between an electrical error signal (e.sub.m(n) and a modelled secondary anti-noise signal ŷ.sub.m(n) with at least one predefined threshold (α, β).

Various implementations include a computational architecture for a personal active noise reduction (ANR) device. The device includes a communication interface that receives an audio stream, a driver, a microphone system and an ANR processing platform. The platform includes a first DSP configured to: receive the audio stream and signals from the microphone system, perform ANR on the audio stream according to a set of parameters in the first DSP, and output a processed audio stream. The platform includes a second DSP configured to: generate state data in response to an analysis of the source audio stream, signals from the microphone system, and the processed audio stream; and alter the operational parameters on the first DSP. The platform includes a general purpose processor configured to: communicate control signals with the communication interface, process state data from the second DSP, and alter the parameters on the first DSP.

In one aspect, a first device may include at least one processor and storage accessible to the at least one processor. The storage may include instructions executable by the at least one processor to establish a peer to peer network between the first device and a second device. The instructions may also be executable to select the first device to generate noise cancellation signals based on the first device being closer to a source of sound than the second device. The instructions may be further executable to use the first device to generate the noise cancellation signals based on sound from the source of sound, and to transmit the noise cancellation signals over the peer to peer network to the second device.

An anti-noise signal generator and a method of generating an anti-noise signal are presented. The anti-noise generator includes a first microphone input to receive a first sigma-delta modulated signal at a microphone sampling frequency. The first microphone input is coupled to a combiner via a first path and a second path. The combiner is adapted to combine a first filtered signal from the first path and a second filtered signal from the second path to generate the anti-noise signal. The first path includes a first digital filter adapted to operate at a filter frequency equal or greater than the microphone sampling frequency. The second path includes a second digital filter. The first digital filter may be a sigma-delta based filter that includes a sigma-delta modulator.

Systems and methods include a digital control module that receives and processes audio data for output through a loudspeaker. An analog block receives the audio data and the power control signal and amplifies the audio data for output. A first processing path includes a buffer to delay the audio data, a first component to combine the buffered audio data and anti-noise. A second processing path includes an absolute value block to receive the audio data and an envelope detector to receive the absolute value data and generate a maximum value for the envelope. An anti-noise path includes an absolute value block configured to determine an anti-noise absolute value which is combined with the absolute value anti-noise data. A power generator receives the output from the envelope detector and updates a power level to approximate a minimum powered needed to process the audio signal.

A method of operating a headphone configured to be removed from and placed in close proximity to a user's ear can include generating an input signal by an input signal generating device. The method can also include determining whether an insertion event has occurred based on the generated input signal and causing the headphone to operate in a low power mode responsive to an absence of an insertion event determination after a first period of time. The method can also include causing the headphone to operate in an ultra-low power mode responsive to the absence of an insertion event determination after a second period of time that occurs after the first period of time, the ultra-low power mode having a lower power consumption than the low power mode.

Sound reduction includes receiving a reference signal corresponding to undesired sound present in the target space, and producing, based on the reference signal, a cancelling signal representative of the undesired sound present in the target space. Sound reduction further includes producing, based on the cancelling signal, sound to destructively interfere with the undesired sound present in the target space, and delaying at least one of the reference signal and the cancelling signal to reduce or compensate for runtime differences between signal paths that transfer the reference signal to the target space.

An audio processing system can include an Analog to Digital Converter structured to receive an analog input signal and convert the analog input signal to a digital input signal, a first processor coupled with the Analog to Digital Converter, the first processor including at least one programmable bi-quadratic filter chain structured to receive the digital input signal from the Analog to Digital Converter and perform audio processing on the received digital input signal at a first clock rate, and a second processor coupled with the first processor and the Analog to Digital Converter and structured to receive the digital input signal from the Analog to Digital Converter and perform audio processing on the received digital input signal at a second clock rate that is different from the first clock rate.

An ambient sound processing method provided includes determining a time-frequency spectrum of an ambient sound in preset duration. A matching scenario is determined from at least one preset scenario according to the time-frequency spectrum of the ambient sound in the preset duration, where a time-frequency spectrum of the matching scenario matches the time-frequency spectrum of the ambient sound in the preset duration. Operation information corresponding to the matching scenario is determined as the operation information to be executed, and an operation is performed according to the operation information to be executed and a subsequently received ambient sound, and an operated signal is determined. The operated signal is mixed to obtain a mixed signal, and the mixed signal is transmitted to a headset, where the mixed signal includes at least an audio signal played by user equipment of a user.