Detecting a divergence in an adaptive system includes the steps of determining a power of a component of an error signal at a first frequency, the component being correlated to a noise-cancellation signal, the noise-cancellation signal being produced by an adaptive filter and being configured to cancel noise within a predetermined volume when transduced into acoustic signal, wherein the error signal represents a magnitude of a residual noise within the predetermined volume; determining a time gradient of the power of the component of the error signal; and comparing a metric to a threshold, wherein the metric is based, at least in part, on a value of the time gradient of the power of the component of the error signal over a period of time.

The present disclosure relates to a noise control apparatus, vehicle having the same and method for controlling the vehicle to reduce indoor noise. In accordance with an aspect of disclosure, the vehicle collects sound by using a sound collector while driving the vehicle; detects vibration occurring in the vehicle by using a vibration detector; detects an occupant in the vehicle by using an occupant detector; generates a virtual reference signal based on an actual reference signal for the detected vibration; acquires location information of the occupant's ear based on the occupant information; generates a virtual error signal based on the acquired ear location information and the actual noise signal for the collected sound; generates a noise control signal based on the virtual error signal and the virtual reference signal; and outputs the generated noise control signal as sound.

A sound signal control device in a device including an input transducer to detect sound in a space in a vehicle, a sensor to image an occupant in the space, and an output transducer to emit sound into the space includes: a controller to generate information indicating a position of a head of the occupant and information indicating a state of the occupant, based on an image imaged by the sensor; a processor to generate a cancellation signal for cancelling noise at the position based on a sound signal representing sound detected by the input transducer and the information, and generate a control signal for controlling sound at the position based on the cancellation signal; and a converter to cause the output transducer to emit a sound corresponding to the control signal. The processor adjusts a degree to which the noise is cancelled, based on the information indicating the state.

A privacy system for a vehicle, including: a window configured to selectively switch between transparent and non-transparent states and to simultaneously have a transparent zone and a non-transparent zone, an elongate touch sensitive sensor provided adjacent to the window, and a controller configured to receive a signal from the elongate touch sensitive sensor and control the transparency of the window such that a transition line between the transparent zone and the non-transparent zone is substantially aligned with and follows a point at which the elongate touch sensitive sensor is being touched.

An earmuffs system for noise reduction including an external microphone used in combination with active noise cancellation technology for the reduction of wind or other noises typically experienced while riding a vehicle such as a motorcycle, snow machine or ATV, the earmuffs system including a first earmuff including a first speaker and a first microphone therein; a second earmuff electrically coupled to the first ear muff, the second ear muff including a second speaker and a second microphone therein; noise cancellation circuitry for receiving first sounds from the first microphone and the second microphone and processing the first sounds by in part canceling the first sounds to form a first sound output that is provided from the first speaker and the second speaker; a third microphone placed external to the first earmuff, the third microphone supplying second sounds for the first speaker to output as a second sound output without the second sounds undergoing noise cancellation processing; and a fourth microphone placed external to the second earmuff, the fourth microphone supplying third sounds for the second speaker to output as a third sound output without the third sounds undergoing noise cancellation processing.

A device (1) for reducing a rolling noise of a vehicle (3) having at least one tire (2), the tire (2) rolling on a roadway on a tire contact patch (4), wherein the device (1) comprises at least one sound absorption element (5) attached to the vehicle (3) in front of, behind and/or laterally of the tire contact patch (4) in the direction of travel (F) of the vehicle (3) and having at least one resonance frequency and a curved first absorber membrane (6) facing the tire contact patch (4), wherein essentially the entire first absorber membrane (6) is oriented normally to a direction of sound propagation (S) emanating from the tire contact patch (4), and the sound absorption element (5) is located at a distance from the tire contact patch (4) which corresponds to a multiple of half a wavelength (λ) assigned to the resonance frequency.

A noise reducing system for a tracked vehicle, the tracked vehicle comprising a cab and at least one track that extends along a direction of travel of the vehicle and comprises at least a plurality of bars, such as metal bars, transverse to the direction of travel. The noise reducing system comprising a control unit and an acoustic wave emitter connected to the control unit for being controlled by the control unit, the noise reducing system comprising an acoustic input and being configured to emit an acoustic equalization wave, phase shifted with respect to the noise and determined on the basis of the acoustic input, to reduce the noise, in particular the noise generated by the tracks.

A signal processing apparatus includes a signal processor configured to: generate a first noise reduction signal using an adaptive filter based on a signal output from a first input apparatus, and cause the generated first noise reduction signal to be output by a first output apparatus; and generate a second noise reduction signal using a feedback filter based on a signal output from a second input apparatus, and cause the generated second noise reduction signal to be output by a second output apparatus. The feedback filter has a fixed feedback coefficient. The first input apparatus is located at a first noise-cancellation target location in an environment, and the second input apparatus is located at a second noise-cancellation target location in the environment, which may be different from the first noise-cancellation target location.

An input signal representative of an undesired acoustic noise in a region is captured by one or more first sensors and processed to generate a cancellation signal. An output signal is generated based on the cancelation signal to cause one or more acoustic transducers to cancel, at least in part, the undesired acoustic noise in the region. A feedback signal representative of residual acoustic noise in the region is captured by one or more second sensors. A characteristic of each of the feedback signal, the cancellation signal, and a combination of the cancellation signal and the feedback signal is determined. One or more thresholds are compared to a ratio of (i) the characteristic of the combination of the cancellation signal and the feedback signal and (ii) a combination of the characteristic of the feedback signal and the characteristic of the cancellation signal to determine a convergence state.

A active noise cancellation (ANC) system may include an adaptive filter divergence detector for detecting divergence of the one or more controllable filters as they adapt, based on various temporal or frequency domain amplitude characteristics. Upon detection of a controllable filter divergence, the ANC system may be deactivated, or certain speakers may be muted. Alternatively, the ANC system may modify the diverged controllable filters to restore proper operation of the noise cancelling system. This may include adjusting a leakage value of an adaptive filter controller.