A noise-cancellation system, including: a noise-cancellation filter configured to generate a noise-cancellation signal; an actuator configured to receive the noise-cancellation signal and to transduce a noise-cancellation audio signal based on the noise-cancellation signal, the noise-cancellation audio signal destructively interfering with an undesired noise in a noise-cancellation zone in a predefined volume; an error sensor configured to output an error sensor signal, the error sensor signal being representative of residual undesired noise in the noise-cancellation zone; a performance cost filter configured to receive and filter the error sensor signal and to output a performance cost filter signal, the performance cost filter signal being representative of the error sensor signal as weighted by a performance cost function; and an adjustment module configured to receive the performance cost filter signal and to adjust the noise-cancellation filter such that the noise-cancellation audio signal minimizes the performance cost filter signal.

A system and method for disabling adaptation in an adaptive feedforward control system at low speeds. The method includes generating a noise signal representative of undesired noise detected by a noise sensor of a vehicle and generating a noise-cancellation signal via a controller within the vehicle. Residual noise resulting from the combination of the acoustic energy of the noise-cancellation signal and the undesired noise is detected by a reference sensor, which generates an error signal based on the residual noise. The error signal and a speed signal from a speed sensor on the vehicle are transmitted to an adaptive processing module for the generation of a filter update signal. The adaptive processing module selectively permits or prevents the filter update signal to adapt filter coefficients of a filter when the speed signal is within a set of conditions.

The disclosure relates to a hearing device comprising a housing accommodating an acoustic transducer inside an inner volume of the housing, the acoustic transducer having an oscillator element configured to generate sound waves, the housing accommodating the acoustic transducer inside an inner volume of the housing. The hearing device further comprises a sound outlet configured to release sound waves from the inner volume into an ear canal. The hearing device may also comprise a microphone configured to be acoustically coupled to the ear canal, and an active feedback control circuit configured to provide an active feedback control signal to modify the sound waves generated by the acoustic transducer.

A noise-cancellation method, comprising the steps of: receiving a value from a noise sensor at a time step; storing the received value in a buffer, the buffer having a length, the buffer further storing a number of additional values, wherein an end value is removed from the buffer to accommodate the received value; providing a previously-computed result, wherein the previously-computed result represents the sum of the square of the values stored in the buffer at a previous time step; adding a square of the received value to the previously-computed result and subtracting a square of the end value from the sum of the received value and the previously computed value in order to yield a newly-computed result and updating a plurality of coefficients of an adaptive filter according to, in part, the value of the newly-computed result.

An earphone (1) comprising an earphone housing (2), a speaker unit (3), the speaker unit (3) comprising a diaphragm (4). A front chamber (29) is defined in the earphone between a front side (31) of the diaphragm (4) and the user (7), when the earphone (1) is worn. A rear chamber (27) is defined between the earphone housing (2) and a rear side (32) of the diaphragm (4). The earphone (1) comprises an active noise cancelling feedback microphone (9), which is arranged in the rear chamber (27) and which comprises a microphone opening (11). The diaphragm (4) comprises a cylindrical part (14), to which a voice coil (12) is attached, and an outer ring part (15) extending from the cylindrical part (14) in a direction away from a centre axis (30) of the diaphragm (4). The feedback microphone (9) is arranged farther from the centre axis (30) than the voice coil (12).

The disclosure includes an acoustic processing network comprising a Digital Signal Processor (DSP) operating at a first frequency and a Real-Time Acoustic Processor (RAP) operating at a second frequency higher than the first frequency. The DSP receives a noise signal from at least one microphone. The DSP then generates a noise filter based on the noise signal. The RAP receives the noise signal from the microphone and the noise filter from the DSP. The RAP then generates an anti-noise signal based on the noise signal and the noise filter for use in Active Noise Cancellation (ANC).

A noise-cancellation method, comprising the steps of: receiving a value from a noise sensor at a time step; storing the received value in a buffer, the buffer having a length, the buffer further storing a number of additional values, wherein an end value is removed from the buffer to accommodate the received value; providing a previously-computed result, wherein the previously-computed result represents the sum of the square of the values stored in the buffer at a previous time step; adding a square of the received value to the previously-computed result and subtracting a square of the end value from the sum of the received value and the previously computed value in order to yield a newly-computed result and updating a plurality of coefficients of an adaptive filter according to, in part, the value of the newly-computed result.

A room monitoring System is provided, comprising: a speaker; a microphone; and a digital signal processor (DSP) adapted to generate and transmit a first audio test signal to the speaker to be broadcast in the room, wherein the first audio test signal comprises a power spectral density that is inversely proportional to its frequency, and wherein the transmitted first audio test signal is reflected within the room, and wherein the DSP is further adapted to process the reflected broadcast first audio test signal received by the microphone, generate and save a frequency-amplitude analysis of the received first audio test signal as an initial reference curve, periodically test the room in a substantially similar manner to generate one or more additional reference curves, and compare the one or more additional reference curves to determine whether they are within a known, predetermined tolerance of the initial reference curve.

A noise-cancellation system includes a noise-cancellation filter configured to generate a noise-cancellation signal based on a noise signal received from a noise sensor; an actuator disposed at a first location within a predefined volume and configured to receive the noise-cancellation signal and to transduce a noise-cancellation audio signal within the predefined volume; a reference sensor disposed at a second location within the predefined volume and to output a reference sensor signal, the reference sensor signal being representative of an undesired noise at the second location; a filter configured to filter the noise-cancellation signal and the reference sensor signal to output a filter output signal, the filter output signal representing an estimate of the undesired nose at a third location remote from the first location and the second location; and an adjustment module configured to adjust the noise-cancellation filter, based on the filter output signal, such that the noise-cancellation audio signal destructively interferes with the undesired noise at the third location.

A system for controlling noise of a vehicle includes: an engine speed sensor configured for detecting a speed of an engine of the vehicle; a microphone detecting noise of the vehicle; an engine state sensor configured for detecting an operating state of the engine; a signal processing controller receiving the speed of the engine, the noise of the vehicle, and the engine operating state and generating amplified noise based on at least one of the received engine speed, the received noise of the vehicle, and the received engine operating state; a signal processing amplifier receiving the engine speed and the amplified noise and generating output noise by amplifying the amplified noise as much as amplification degree based on the speed of the engine; and a sound transmitting device receiving the output noise and transmitting the output noise or a separate sound source corresponding to the output noise to the vehicle.