Active noise cancellation systems, components, and methods are provided with single-source forward cancellation using a direction-dependent filter response. One illustrative active sound cancelling device includes: a primary external microphone that produces a primary receive signal; a secondary external microphone that produces a secondary receive signal, the primary and secondary receive signals representing ambient audio that potentially includes sound having a predominate direction of arrival; a speaker that converts an output signal into internal audio to at least partly cancel said sound, the output signal including a forward cancellation signal; a forward filter that operates solely on the primary receive signal to produce the forward cancellation signal; and a direction finder that operates on the primary and secondary receive signals to derive an estimate of said predominate direction of arrival, the direction finder adjusting the forward filter to implement a filter response corresponding to said estimate.

A biquad hybrid active noise cancellation (ANC) device includes a reference microphone (MIC), an error MiC, a speaker, and a controller. The controller is connected to the reference MiC, the error MiC, and the speaker, wherein the controller includes a feedforward biquad ANC filter, a feedback biquad ANC filter, and a mixer, the feedforward biquad ANC filter processes reference noise to generate a feedforward noise control signal, the feedback biquad ANC filter processes residual noise received by the error MiC to generate a feedback noise control signal, and the feedforward noise control signal generated by the feedforward biquad ANC filter and the feedback noise control signal generated by the feedback biquad ANC filter are added by the mixer and transmits to the speaker for playing.

An active noise control device includes a control signal generating unit including a first adaptive filter configured to generate a control signal by performing a filtering process on a reference signal corresponding to noise, an identifying unit configured to identify a peak frequency in an impedance frequency characteristic of an actuator, a peak frequency storage unit configured to store an initial peak frequency of the actuator, a first determination unit configured to determine whether or not a difference between the peak frequency currently identified and the initial peak frequency is greater than or equal to a threshold value, and a control unit configured to change a characteristic of the control signal generated by the control signal generating unit when the first determination unit determines that the difference is greater than or equal to the threshold value.

An active noise control device includes a first adaptive filter configured to generate a control signal by performing a filtering process on a reference signal corresponding to noise, and a first filter coefficient updating unit configured to update a filter coefficient of the first adaptive filter based on based on the reference signal and an added error signal acquired by adding a first error signal acquired by detecting residual noise by a first microphone and a second error signal acquired by detecting residual noise by a second microphone.

An active noise control device includes a basic signal generating unit configured to generate a basic signal corresponding to a resonance frequency of a vibration sensor, a first adaptive filter configured to generate a sensor resonance simulation signal simulating a signal acquired while the vibration sensor is resonating by performing a filtering process on the basic signal, a computation unit configured to calculate a second reference signal that is a difference between a first reference signal acquired by the vibration sensor and the sensor resonance simulation signal, and a second adaptive filter configured to generate a control signal by performing a filtering process on the second reference signal.

Embodiments include a method and noise cancelling system for cancelling noise in a vehicle by operating at least one noise cancelling means in a first mode of operation to output a noise cancelling signal; receiving at least one input indicative of a state of the vehicle; determining if noise cancelling error conditions are present based on the at least one received input indicative of a state of the vehicle; and operating at least one noise cancelling means in a second mode of operation if noise cancelling error conditions are determined as present.

An electronic system includes a fan module, an embedded controller, an error microphone, an active noise cancellation controller, and a micro speaker module. The error microphone is configured to output an error signal by detecting the noise level during the operation of the electronic system. According to the error signal and the fan information provided by the embedded controller, the active noise cancellation controller calculates the narrow-band noises associated with the actual single-blade fundamental frequency noise and the actual BPF fundamental frequency noise generated by the fan module, and drives the micro speaker module accordingly for providing a noise cancellation signal. The error signal may be reduced to zero by adaptively adjusting the noise cancellation signal for canceling the noises generated during the operation of the electronic system.

A headset with automatic noise reduction mode switching is provided to enable better call experience when conducting a call. The headset comprises at least one or more earphones, one or more microphones, a processor, and an active noise cancellation circuit, connected at least with the processor. The processor is configured to determine whether a call is being conducted using the headset, and if a call is being conducted, to switch the active noise cancellation circuit from a first ANC mode to a second ANC mode.

An active noise cancelling system (20) comprising: an earphone (8′) comprising: an electro-acoustic driver (11); and at least one sensing microphone (12, 13); tunable active noise cancelling circuitry (7) operative to receive a signal from the at least one sensing microphone (12, 13), the tunable active noise cancelling circuitry (7) being pre-configured in a standard tuning for a reference ear and comprising at least one noise-control filter (14, 15); and a tuning module (24) operative to configure the earphone (8′) for an individual wearer by: comparing acoustic coupling of the earphone (8′) to the individual wearer's ear with acoustic coupling to the reference ear to determine a deviation in acoustic coupling; and using the determined deviation in acoustic coupling to modify the tunable active noise cancelling circuitry (7) by a predetermined degree based on the determined deviation in acoustic coupling.

A fan control system applied to N fans inside a computer system is disclosed, comprising: a main microphone, a control circuitry, a wave generation circuitry and a number N of fan controllers. The control circuitry calculates a basic frequency value according to a temperature inside the computer system, and continuously updates a parameter by any known optimization algorithm according to a main audio signal from the main microphone. The wave generation circuitry generates N square waves according to the basic frequency value and the parameter. The N fan controllers respectively form and transmit N modulation signals to the N fans according to the N square waves and N tachometric signals from the N fans. The parameter is one of a frequency variation and a set of phase differences, and the N square waves have the same frequency.