An integrated circuit for implementing at least a portion of a personal audio device may include an output for providing a signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the transducer, a reference microphone input for receiving a reference microphone signal indicative of the ambient audio sounds, an error microphone input for receiving an error microphone signal indicative of the output of the transducer and the ambient audio sounds at the transducer, and a processing circuit configured to implement an adaptive infinite impulse response filter having a response that generates the anti-noise signal to reduce the presence of the ambient audio sounds at the error microphone and implement a coefficient control block that shapes the response of the adaptive infinite impulse response filter in conformity with the error microphone signal by generating coefficients that determine the response of the adaptive infinite impulse response filter in order to minimize the ambient audio sounds at the error microphone, wherein the coefficient control block selects the coefficients from a library of filter entries, each filter entry of the library of filter entries defining a respective response for the adaptive infinite impulse response filter.

A wearable device is provided and includes a plurality of speakers including a first speaker, a second speaker, and an N.sup.th speaker, a plurality of digital to analog converter (DAC)s including a first DAC connected to the first speaker, a second DAC connected to the second speaker, and an N.sup.th DAC connected to the N.sup.th speaker, an audio signal processing module including N DAC output paths configured to filter an audio signal according to each frequency band and output the audio signal, a memory; and a processor electrically connected to the plurality of DACs, the audio signal processing module, and the memory, wherein the memory includes instructions causing the processor to, when the audio signal is reproduced, analyze a frequency component included in the audio signal, activate the N DAC output paths when the frequency component included in the audio signal has a full band range, activate only a DAC output path for processing a specific frequency band among the N DAC output paths when the frequency component included in the audio signal has only the specific frequency band, and output the audio signal through a speaker connected to the activated DAC output path.

An active noise reduction device includes: an adaptive filter that generates a cancelling signal by applying an adaptive filter to a reference signal that has a correlation with noise in a space in an automobile, the cancelling signal being used to output a cancelling sound for reducing the noise; and a filter coefficient updater that calculates a coefficient of the adaptive filter based on a predetermined update equation. At a first timing at which the output of the cancelling sound is started, the filter coefficient updater uses a first coefficient as an initial value of the update equation, the first coefficient being the coefficient of the adaptive filter calculated by the filter coefficient updater at a second timing that is prior to the first timing.

An active noise control (ANC) system includes a speaker and one or more processors programmed to implement a delayless subband filtered-x least mean square control algorithm. The algorithm includes a variable bandwidth discrete Fourier transform filter bank having a number of subbands such that the system, in response to a broadband white noise reference signal indicative of road noise in the vehicle, exhibits a uniform gain spectrum across a frequency range defined by the subbands and partially cancels the road noise via output of the speaker.

The present disclosure is a noise cancellation system including: a microphone that converts a sound wave into an electrical signal; a transmission line that propagates the electrical signal from the microphone; a speaker that reproduces a sound wave from the electrical signal from the transmission line; a phase inversion circuit that is provided between the microphone and the speaker, and inverses the phase of the electrical signal; a gain adjustment circuit that is provided between the microphone and the speaker, and adjusts a gain for amplifying the electrical signal; and a delay adjustment circuit that is provided between the microphone and the speaker, and adjusts the amount of delay of the electrical signal.

The present disclosure provides a method for determining an arrangement of reference sensors for active road noise control (ARNC) in a vehicle with an automatic calibration system. The method includes mounting a plurality of vibrational sensors on a plurality of structure elements of the vehicle to generate a plurality of vibrational input signals and mounting at least one microphone inside a cabin of the vehicle to capture at least one acoustic input signal. The method further includes determining an arrangement of reference sensors from the plurality of vibrational sensors by determining a subset of vibrational sensors which sense the main mechanical inputs of road noise contributing to the at least one acoustic input signal.

The embodiments of the present disclosure disclose an earphone with antenna peripherals and an audio playback method. A specific implementation of the earphone with antenna peripherals comprises a sound cavity assembly, a battery assembly, and an antenna ear handle, wherein the sound cavity assembly includes a front sound cavity and a rear sound cavity, an earphone motherboard and a speaker are arranged between the front sound cavity and the rear sound cavity, the front sound cavity is provided with a sound outlet; the battery assembly includes a front battery cavity and a rear battery cavity, the front battery cavity and the rear battery cavity are connected, and a battery is arranged between the front battery cavity and the rear battery cavity; the sound cavity assembly and the battery assembly are connected through the antenna ear handle, and the earphone motherboard and the battery are connected through a power cord.

Various implementations include a method for implementing a computational architecture for a personal active noise reduction (ANR) device. A method includes receiving a source audio stream with a first DSP and performing ANR on the source audio stream utilizing operational parameters stored in the first DSP; outputting a processed audio stream from the first DSP; generating state data with a second DSP in response to an analysis of at least one of the source audio stream, microphone inputs and the processed audio stream, and communicating signals to the first DSP over a common bus coupled to the first and second DSPs to alter the operational parameters in the first DSP; and utilizing a general purpose processor coupled to both the first DSP and the second DSP to communicate control signals with a communication interface, process state data from the second DSP, and alter the operational parameters in the first DSP.

An input signal representative of an undesired acoustic noise in a region is captured by one or more first sensors and processed to generate a cancellation signal. An output signal is generated based on the cancelation signal to cause one or more acoustic transducers to cancel, at least in part, the undesired acoustic noise in the region. A feedback signal representative of residual acoustic noise in the region is captured by one or more second sensors. A characteristic of each of the feedback signal, the cancellation signal, and a combination of the cancellation signal and the feedback signal is determined. One or more thresholds are compared to a ratio of (i) the characteristic of the combination of the cancellation signal and the feedback signal and (ii) a combination of the characteristic of the feedback signal and the characteristic of the cancellation signal to determine a convergence state.

A noise cancellation circuit includes: a first filter circuit for filtering a first input signal according to a first filter coefficient to generate a first filtered signal; a signal processing circuit for generating a feedback signal according to a second input signal and an audio signal; a second filter circuit for filtering the feedback signal according to a second filter coefficient to generate a second filtered signal; a first multiplication circuit for multiplying the first filtered signal by a first scale to generate a first intermediate signal; a second multiplication circuit for multiplying the second filtered signal by a second scale to generate a second intermediate signal; a first adder circuit for adding the first intermediate signal to the second intermediate signal to generate a noise cancellation signal; and a second adder circuit for adding the noise cancellation signal to the audio signal to generate an output signal.