A noise controlling method includes generating a reference signal representing a primary noise, generating a secondary noise in response to a control signal for cancelling the primary noise, generating an error signal representing a superposition of the primary and secondary noises at a position, generating an additional reference signal, secondary noise, or additional error signal, and generating the control signal for generating the secondary noise using adaptive subband filtering based on the reference and error signals, the generating the control signal including decomposing the reference signal and the error signal into a subband reference and error signal for each subband, updating subband adaptive filters for a subband based on the subband reference signal and the subband error signal, updating a fullband adaptive filter based on the updated subband adaptive filter, and generating the control signal by filtering the reference signal by the updated fullband adaptive filter.

The subject matter described herein provides systems and techniques for filtering an audio signal using active noise cancellation (ANC). A channel response finite impulse response (CR FIR) filter in a conventional ANC system may be replaced with a two filter cascade configuration. The first filter in the cascade filter configuration may be a CR FIR filter with interleaved zero coefficients and the second filter may be a response interpolator filter that is a fixed interpolator. The CR FIR filter in the two filter cascade may be adaptive and may have its non-zero coefficients tracked, updated, adapted, and/or computed. The fixed interpolator in the two filter cascade may be fixed and therefore non-adaptive. The channel frequency response profile of the two filter cascade configuration may be similar to the channel frequency response profile of the conventional CR FIR filter that the cascade filter configuration replaces.

A method may include adaptively generating an anti-noise signal from filtering a reference microphone signal with an adaptive filter in conformity with an error microphone signal and the reference microphone signal. The method may also include adjusting the response of the adaptive filter by combining injected noise with the reference microphone signal and receiving the injected noise by a copy of the adaptive filter so that the response of the copy is controlled by the adaptive filter adapting to cancel a combination of the ambient audio sounds and the injected noise and controlling the response of the adaptive filter with the coefficients adapted in the copy, whereby the injected noise is not present in the anti-noise signal and wherein each of a sample rate of the copy and a rate of adapting of the adaptive filter is significantly less than a sample rate of the adaptive 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.

Adaptations for in-vehicle adaptive noise-canceling (ANC) technology are described. An example in-vehicle audio system includes ANC circuitry coupled to one or more error microphones. The ANC circuitry being configured to process audio data received from the one or more error microphones to determine a distinction between the engine-external noise and the engine noise. The ANC circuitry is further configured to alter, based on the distinction determined between the engine-external noise and the engine noise, a convergence between two or more ANC filters to form altered-convergence ANC filtering coefficients.

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.

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 characterize a malfunction in response to instability or error condition events detected by the second DSP.

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 technology described in this document can be embodied in a computer-implemented method that includes receiving, at one or more processing devices, a plurality of values representing a set of coefficients of an adaptive filter over a period of time, and identifying, by the one or more processing devices based on the plurality of values, a phase error associated with a transfer function of the adaptive filter. The method also includes adjusting, based on the identified phase error, a phase associated with the transfer function of the adaptive filter such that coefficients calculated using the adjusted transfer function reduce the phase error. The method further includes determining a set of coefficients for the adaptive filter based on the adjusted transfer function, and programming the adaptive filter with the determined set of coefficients to enable operation of the adaptive filter.

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.