A processor is configured to perform headphone playback with a playback audio signal. The processor produces a feedback signal from an internal microphone, compresses the feedback signal according to a variable compressor setting, and determines a context of usage of the headphone, as being one of running or jogging, transportation, and critical listening. In response, the processor changes the variable compressor setting and drives the headphone speaker with the compressed feedback signal combined with the playback audio signal. Other aspects are also described and claimed.

A signal processing apparatus is configured to preprocess a sound wave signal and output a processed audio signal through an electromagnetic wave. The signal processing apparatus includes: a receiving unit, configured to receive at least one sound wave signal; a conversion unit, configured to convert the at least one sound wave signal to at least one audio signal; a positioning unit, configured to determine position information related to the at least one sound wave signal; a processing unit, configured to determine a sending time point of at least one audio signal based on the position information and a first time point, where the first time point is a time point at which the receiving unit receives the at least one sound wave signal; and a sending unit, configured to send the at least one audio signal through the electromagnetic wave.

A processor is configured to perform headphone playback with a playback audio signal. The processor produces a feedback signal from an internal microphone, compresses the feedback signal according to a variable compressor setting, and determines a context of usage of the headphone, as being one of running or jogging, transportation, and critical listening. In response, the processor changes the variable compressor setting and drives the headphone speaker with the compressed feedback signal combined with the playback audio signal. Other aspects are also described and claimed.

The present disclosure presents a feedback active noise control system and strategy with online secondary-path modeling, and belongs to the technical field of active noise control. The linear prediction subsystem takes the residual noise as its input and separates the remaining sinusoidal noise from the broadband noise. The remaining sinusoidal noise is used effectively not only to update the controller but also to scale the auxiliary noise, while the broadband noise serves as a desired input of online secondary-path modeling subsystem. In this way, the coupling between the controller and the online secondary-path modeling subsystem is significantly mitigated, leading to both faster convergence and improved noise reduction performance. A practical scheme for refreshing the entire system is also developed to enhance its robustness against even abrupt changes with the secondary path or the primary noise. The present disclosure enhances the applicability of feedback active noise control in practical applications.

An active noise reduction system and method, and a storage medium are provided. In the system, a first signal acquisition circuitry acquires an external noise signal at a noise cancellation spot, and transmits the acquired external noise signal to a noise control system including a first frequency nonlinear transformation circuitry, a first filter circuitry and an inverter. The first frequency nonlinear transformation circuitry receives the external noise signal, and expands at least one target frequency band of the external noise signal based on a frequency nonlinear transformation mapping function to generate a first transformed external noise signal, the first filter circuitry filters the first transformed external noise signal to generate a filtered external noise signal, and the inverter performs inversion on the filtered external noise signal to generate a noise cancellation signal; and the signal output circuitry receives and outputs the noise cancellation signal to cancel an actual noise.

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.

A variable update step size is determined in proportion to a magnitude ratio or magnitude difference between a first residual signal and a second residual signal. The first residual signal is obtained by using adaptive filter coefficient sequence, where the adaptive filter coefficient sequence has been obtained in previous operations of the adaptive equalizer. The second residual signal is obtained by using a prior update adaptive filter coefficient sequence, where the prior update adaptive filter coefficient sequence is obtained by performing a coefficient update with an arbitrary prior update step size on the adaptive filter coefficient sequence having been obtained in previous operations of the adaptive equalizer.

A computer-implemented method for automatically optimizing a hybrid active noise cancellation system, the hybrid active noise cancellation system comprising a feedback filter and a feedforward filter, the method comprising optimizing the feedforward filter, thereby optimizing the hybrid active noise cancellation system, wherein optimization of the feedforward filter is dependent on the feedback filter.

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.

An ASC apparatus, which actively generates a sound effect inside a cabin of a vehicle provided with an internal combustion engine and an electric motor as driving sources, includes: a reference signal generating unit which generates a harmonic reference signal based on a vehicle-speed-corresponding frequency, being a frequency based on a vehicle speed, by referring to waveform data; a driver seat speaker which outputs a sound including the sound effect; and a signal processing unit which generates a control signal that forms the sound effect by multiplying the reference signal by a sound effect gain related to the reference signal, and outputs the control signal to the driver seat speaker. The signal processing unit sets the sound effect gain based on a state of charge of a storage battery.