Noise abatement within a signal stream containing unwanted signal referred to as noise is performed by acquiring a digitized noise signal and using a digital processor circuit to subdivide the acquired noise signal into different frequency band segments and thereby generate a plurality of segmented noise signals. Then individually for each segmented noise signal, the processor shifts in time the segmented noise signal by an amount dependent on a selected frequency of the segmented noise signal to produce a plurality of shifted segmented noise signals. The precise time shift applied to each noise segment considers the frequency content of the segment and the system processing time. Individually for each segmented noise signal, amplitude scaling is applied. The shifted and amplitude-scaled segmented noise signals are then combined to form a composite anti-noise signal which is output into the signal stream to abate the noise through destructive interference.

An electronic system includes a fan module, an embedded controller, a reference microphone, an error microphone, an active noise cancellation controller, and a micro speaker module. The reference microphone outputs a wide-band noise signal associated with the operation of the fan module. The error microphone outputs an error signal by detecting the noise level of the electronic system. According to the wide-band noise signal, the error signal and the fan information provided by the embedded controller, the active noise cancellation controller provides a speaker control signal by calculating narrow-band and wide-band noises of the fan module, and drives the micro speaker module to provide a noise cancellation signal which is adjusted according to the wind pressure under the current fan speed of the fan module. The error signal may be reduced to zero by adaptively adjusting the noise cancellation signal for canceling the noises in the electronic system.

A helmet including an active noise cancellation (ANC) system which includes a first reference microphone for measuring sound pressure at a first location on a first side of the helmet, the first location between a defined spatial region and a first source of sound and a second reference microphone for measuring sound pressure at a second location, different to the first location, on the first side. The second location is between the defined spatial region and a second source of sound. A loud speaker is provided in or adjacent to the defined spatial region. A control unit determines, based on output signals from the first and second microphones, a drive signal for driving the loudspeaker to generate a sound signal that at least partially attenuates, in the defined spatial region and in the first frequency range, the sound signals from the first and second noise sources.

A personal audio device, such as a wireless telephone, includes noise canceling that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is provided proximate the speaker to measure the output of the transducer in order to control the adaptation of the anti-noise signal and to estimate an electro-acoustical path from the noise canceling circuit through the transducer. The anti-noise signal is adaptively generated to minimize the ambient audio sounds at the error microphone. A processing circuit that performs the adaptive noise canceling (ANC) function also filters one or both of the reference and/or error microphone signals, to bias the adaptation of the adaptive filter in one or more frequency regions to alter a degree of the minimization of the ambient audio sounds at the error microphone.

The present invention discloses a howling suppression method and device applied to an ANR earphone. The method comprises: collecting signals by using a first microphone and a second microphone; wherein the first microphone is arranged in a position outside an auditory meatus when said ANR earphone is worn, and the second microphone is arranged in a position inside the auditory meatus when the ANR earphone is worn; according to a relation between signals collected by the first microphone and the second microphone, judging whether the current state of said ANR earphone is a state unable to produce a howling or a state able to produce a howling; and when the current state of said ANR earphone is a state able to produce a howling, starting processing for preventing howling production. The technical scheme can achieve that the ANR earphone does not produce a howling all the time.

A sound-modulating device used in a confined space is provided. The sound-modulating device includes an event detector and an audio module in communication with each other. The event detector detects an event and generates a trigger signal in response to the detected event. The audio module plays a music segment in response to the trigger signal. The frequencies of the music segment range from 20 Hz to 20000 Hz. The intensities of the music segment are smaller than or equal to 75 dB.

Noise abatement within a signal stream containing unwanted signal referred to as noise is performed by acquiring a digitized noise signal and using a digital processor circuit to subdivide the acquired noise signal into different frequency band segments and thereby generate a plurality of segmented noise signals. Then individually for each segmented noise signal, the processor shifts in time the segmented noise signal by an amount dependent on a selected frequency of the segmented noise signal to produce a plurality of shifted segmented noise signals. The precise time shift applied to each noise segment considers the frequency content of the segment and the system processing time. Individually for each segmented noise signal, amplitude scaling is applied. The shifted and amplitude-scaled segmented noise signals are then combined to form a composite anti-noise signal which is output into the signal stream to abate the noise through destructive interference.

Provided is an information processor including a signal processing section that acquires a first signal to be detected by an acoustic input section of a first unit including the acoustic input section disposed within a predetermined distance from one ear hole of a user in a state of being worn by the user, acquires a second signal, which indicates a noise generated from a noise source, to be acquired by a second unit, and generates a noise cancellation signal directed to the noise on the basis of the first signal and the second signal.

A sensor is configured to infer a rotational speed of a tire of a vehicle. A frequency generator is configured to synthesize frequencies of a tire cavity resonance according to the rotational speed of the tire to generate a sense signal. An active noise control filter is configured to generate an antinoise signal from the sense signal. A loudspeaker configured to convert the antinoise signal into antinoise and to radiate the antinoise to a listening position. The antinoise signal is configured so that the antinoise reduces sound of the tire cavity resonance at the listening position.

An apparatus for canceling noise at an ear speaker includes a wideband active noise cancellation filter having a first bandwidth and configured to generate a wideband anti-noise signal from a received reference noise signal, a narrowband active noise cancellation filter having a second bandwidth smaller than the first bandwidth and configured to generate a narrowband anti-noise signal from an error noise signal, a filter between the ear speaker and an error microphone and configured to generate a feedback noise signal, and a controller. The controller is configured to eliminate the error noise signal by modifying coefficients of the wideband active noise cancellation filter and the narrowband active noise cancellation filter in response to the wideband anti-noise signal, the narrowband anti-noise signal, and the feedback noise signal.