A noise cancellation system for cancelling sounds within a vehicle. The noise cancellation system includes microphones, a camera, a controller, and speakers. The microphones are disposed adjacent to occupant locations, and configured to generate microphone signals representative of noise sounds and cancellation audio sounds. The camera is configured to generate a video signal that captures head configurations of the occupants. The controller is configured to receive rotor control signals, calculate hearing locations based on tracking data of the head configurations of the occupants, and generate a speaker signals based on the hearing locations, the microphone signals, and the rotor control signals. The speakers are configured to generate the cancellation audio sounds. The cancellation audio sounds attenuate the noise sounds.

An apparatus for synthesizing an engine sound according to an embodiment of the present invention comprises: a memory for storing a plurality of explosion sound samples corresponding to a plurality of cylinders included in a cylinder module, respectively; a sound output unit; and a processor for calculating explosion periods of the plurality of cylinders, and overlapping the plurality of samples stored according to the calculated explosion periods on explosion noises of corresponding cylinders, respectively, to output a synthesized virtual engine sound through the sound output unit.

A treadmill having a running deck comprising a motor arranged to drive movement of a tread belt, a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions are executable by the processor to determine an anti-phase waveform based on waveform attributes of a noise emitted from the treadmill and to cause a sound of the anti-phase waveform to be emitted into a surrounding environment.

An electric powered work machine according to one aspect of the present disclosure includes a first and a second digital filters, a control sound source, an error sensor, and a characteristics adjustor. The first digital filter includes a series of taps and generates a control signal. The control sound source produces an artificial noise in accordance with the control signal. The error sensor converts a synthesized sound of the artificial noise and a target noise at a canceling location to an error signal. The second digital filter includes N taps and generates a filtered reference signal. The characteristics adjustor uses the error signal and the filtered reference signal to adjust a coefficient of each tap of M taps in the series of taps. Each of M and N is a positive integer satisfying M<N.

Noise cancellation systems and methods are provided that receive a reference signal representative of a noise to be reduced and provide a noise cancellation signal based upon the reference signal. Some examples include a feedback signal representative of a residual noise in the environment. At least one of the reference signal, the noise cancellation signal, or the feedback signal is filtered to remove components based upon a rotational rate of a rotating equipment associated with the environment, such as an engine of a vehicle. Accordingly, the noise cancellation system may not interfere with sounds related to the engine.

There is provided an ear cup including a housing containing a filter assembly and a motor-driven impeller for creating an airflow through the filter assembly, the housing including an air outlet downstream from the filter assembly for emitting the filtered airflow from the housing. The ear cup further includes an acoustic driver carried by or mounted to, either directly or indirectly, the housing, a reference internal noise sensor disposed within the housing, and a reference ambient noise sensor carried by or mounted to, either directly or indirectly, the housing. The ear cup further includes active noise control circuitry that is configured, in a first operating state, to use a signal provided by the reference internal noise sensor to operate the acoustic driver and, in a second operating state, to use a signal provided by the reference ambient noise sensor to operate the acoustic driver.

Disclosed herein are methods for operating an apparatus for generating acoustic compensation signals used to compensate acoustic signals from operation of a motor-vehicle engine, comprising the steps: providing an EOC device, which is designed to generate acoustic compensation signals used to compensate acoustic signals that result from the operation of the engine; providing a device configured using the EOC device as a model; determining at least one audio signal to be output into a passenger compartment of a motor vehicle by means of an audio output device, before said audio signal is captured by an audio capturing element associated with the EOC device; applying an evaluation specification to evaluate the at least one audio signal with respect to at least one evaluation criterion; generating evaluation information with respect to the at least one evaluation criterion; controlling the operation of the EOC device on the basis of the evaluation Information.

A method of masking wind turbine noise from a wind turbine. Masking noise is generated to produce resultant noise with a modulation depth which is less than a modulation depth of the wind turbine noise and an average level which is greater than an average level of the wind turbine noise. The masking noise is either un-modulated masking noise with a substantially constant level, or amplitude-modulated masking noise which is phase-shifted relative to the wind turbine noise and has a modulation depth which is less than the modulation depth of the wind turbine noise.

A fan blade assembly having integrated microphones to measure acoustic energy levels uses speakers controlled by a control unit to output anti-acoustic energy vibrations. Specific embodiments wherein the speakers and microphones are radially displaced around the fan blade assembly are also disclosed.

A method of masking wind turbine noise from a wind turbine Masking noise is generated to produce resultant noise with a modulation depth which is less than a modulation depth of the wind turbine noise and an average level which is greater than an average level of the wind turbine noise. The masking noise is either un-modulated masking noise with a substantially constant level, or amplitude-modulated masking noise which is phase-shifted relative to the wind turbine noise and has a modulation depth which is less than the modulation depth of the wind turbine noise.