A road noise cancellation (RNC) system is provided with at least one loudspeaker to project anti-noise sound within a passenger cabin of a vehicle in response to an anti-noise signal; and a controller. The controller is programmed to: determine a coherence value between a noise signal indicative of road induced noise and an error signal indicative of noise and the anti-noise sound within the passenger cabin; estimate a noise reduction value based on the coherence value; filter the noise signal and the error signal based on the estimated noise reduction value; and generate the anti-noise signal based on the filtered noise signal and the filtered error signal.

A system is provided for actively mitigating noise caused by vibration of a thin vehicle front windshield in an occupant compartment of a vehicle. The system includes a pair of laser scanners configured to be mountable inside the vehicle occupant compartment. Each laser scanner is configurable to scan an associated initial portion of the windshield simultaneously with the other laser scanner, when the windshield is vibrating.

The invention provides an active noise reduction system which may be self-contained within a headset of the system, wherein circuitry within the system applies an active noise reduction profile to a signal to the speakers in the headset, to provide active noise reduction to the user of the headset, the system being arranged to receive power both from a power supply external to the system and from a battery of the system and to automatically modify the active noise reduction applied, in dependence on whether or not the system is connected to an external power supply.

A simulation test system and method for vehicle road noise cancellation (RNC) are provided in one or more embodiments of the present disclosure. The simulation test system may include a vehicle RNC simulation system and a power amplifier. The vehicle RNC simulation system is configured to simulate an RNC system in a vehicle environment. The power amplifier is configured to execute an RNC algorithm and may perform data communication with the vehicle RNC simulation system. The vehicle RNC simulation system transmits acceleration data representing an acceleration signal and microphone data representing a microphone signal to the power amplifier as inputs to the RNC algorithm in the power amplifier. Moreover, the vehicle RNC simulation system may receive speaker data representing a speaker signal from the power amplifier. The vehicle RNC simulation system includes a secondary path simulation model and a signal flow simulation model.

An active noise reduction system includes a canceling sound output device configured to output a canceling sound for canceling a noise, a noise signal generator configured to generate noise signals based on the noise, and a controller configured to control the canceling sound output device based on the noise signals, wherein the controller is configured to acquire buffer data in which the noise signals are stored in a time series, generate a plurality of divided data by dividing the buffer data, calculate a correlation value of the buffer data based on the plurality of divided data, detect presence/absence of disturbance mixed in the buffer data based on the correlation value, and switch control over the canceling sound output device according to the presence/absence of the disturbance mixed in the buffer data.

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.

In at least one embodiment, a system for performing active noise cancelation in a vehicle is provided. The system includes an adaptive filter and an adjustment controller. The adaptive filter is configured to control a loudspeaker to generate anti-noise to cancel undesired noise in the vehicle. The adjustment controller is programmed to receive a reference signal from one or more accelerometers. Each reference signal includes a frequency that is indicative of a force acting on a portion of the vehicle. The adjustment controller is programmed to compare the frequency to a predetermined frequency threshold and to control a first filter to filter to the frequency based on the comparison of the frequency to the predetermined frequency threshold. The adjustment controller is programmed to transmit a filtered reference signal to the adaptive filter to generate the anti-noise without influence of the frequency of the reference signal.

An apparatus for improving the sound of a vehicle according to one embodiment of the present invention, may comprise: a window open/closed detection sensor for detecting the open/closed state of a window of the vehicle; a car door open/closed detection sensor for detecting the open/closed state of a car door of the vehicle; a speed sensor for measuring the speed of the vehicle; a microphone; a memory; and a processor for adjusting a coefficient of an adaptive filter used for an engine order cancellation (EOC) function, on the basis of the opened degree of the window and the speed, when the car door is closed, the window is open, and the magnitude of noise inputted to the microphone is less than or equal to a threshold magnitude.

A system for actively mitigating a buffeting noise in an occupant compartment of a vehicle when the vehicle is moving. The system is configured to determine an estimated effective volume of the occupant compartment, and to determine if a single window of the vehicle occupant compartment is open. Responsive to a determination that a single window of the vehicle occupant compartment is open, and using the estimated effective volume of the occupant compartment, an estimated buffeting noise frequency is determined. Responsive to the estimated buffeting noise frequency, the system determines characteristics of a sound configured to cancel a buffeting noise generated inside the occupant compartment while the vehicle is moving. The system may then control operation of a noise cancelling signal generating system to generate the sound having characteristics configured to cancel the buffeting noise inside the occupant compartment.

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