Active noise cancellation systems and methods include a feedforward path configured to receive a reference signal comprising ambient noise and adaptively generate an anti-noise signal to cancel the ambient noise and comprising an adaptive gain component configured to adaptively adjust a gain of the anti-noise signal, and a logic device configured to determine a leakage profile based on the adaptive gain component. The feedforward path includes a feedforward adaptive filter tuned to generate the anti-noise signal corresponding to the reference signal in accordance with the determined leakage profile. The leakage profile is selected from a plurality of stored leakage profiles that are tuned for a corresponding gain, and which corresponds to an ear coupling condition associated with a fit between the active noise cancellation system and a user. An adaptive transparency filter receives the reference signal and generates an ambient inclusion signal for output to a user.

In a method for determining a response function of a noise cancellation enabled audio device, the audio device is placed onto a measurement fixture, wherein a loudspeaker of the audio device faces an ear canal representation of the measurement fixture. A first and a second response function between an ambient sound source and a test microphone located within the ear canal representation are measured while parameters of a noise processor of the audio device are set to a proportional transfer function with respective first and second gain factors being different from each other. A model response function is determined based on the first and the second response function and on the first and the second gain factor.

Two subsystems, each including a microphone, a speaker, a canceling sound-generating adder, an error-computing adder, and two adaptive filters and two auxiliary filters that accept two noises as input, are provided in correspondence with two cancellation positions. Each canceling sound-generating adder adds together the outputs from the adaptive filters and outputs the result to the speaker of each subsystem. Each error-computing adder adds together the output from the microphone of the subsystem and the output from the auxiliary filter of the subsystem, and the result is treated as the error of the adaptive filters of each subsystem. A transfer function is learned in advance and set in each auxiliary filter such that each error computed by each error-computing adder becomes zero (0) when a transfer function in which each noise is canceled at each cancellation position in a predetermined standard acoustic environment is set in each adaptive filter.

An active noise control unit generates a noise canceling sound of a single frequency that cancels engine sound heard by an occupant and outputs the noise canceling sound to a speaker through an amplifier. A second harmonic detector and a third harmonic detector detect a magnitude of a harmonic component of the noise canceling sound included in sound collected by a microphone. A controller controls a frequency of the noise canceling sound generated by the active noise control unit to a fundamental frequency of the engine sound based on a rotation frequency of the engine, and in addition, causes an output level control unit to control a level of the noise canceling sound to be output to the amplifier so that the level of the noise canceling sound becomes higher when the magnitude of the harmonic component exceeds a predetermined threshold value.

For example, an apparatus may include an input to receive input information including a Heating, Ventilation and Air Conditioning (HVAC) input including HVAC configuration information corresponding to a configuration of an operation of an HVAC system of a vehicle; a plurality of noise inputs representing acoustic noise at a plurality of noise sensing locations; and a plurality of residual-noise inputs representing acoustic residual-noise at a plurality of residual-noise sensing locations within at least one sound control zone in the vehicle; a controller configured to determine a sound control pattern to control sound within the at least one sound control zone in the vehicle, the controller configured to determine the sound control pattern based on the HVAC input, the plurality of noise inputs and the plurality of residual-noise inputs; and an output to output the sound control pattern to a plurality of acoustic transducers.

The technology described in this document can be embodied in a method that includes receiving a plurality of representations of the signal corresponding to samples of the signal within a frame of predetermined time duration, and estimating a power spectral density (PSD) for each of a plurality of frequency bins. The PSD for a particular frequency bin is estimated based on a smoothing parameter calculated from a noise estimate for the particular frequency bin as obtained from samples corresponding to a preceding frame. The method also includes generating, based on the PSD for each of the plurality of frequency bins, an estimate of the steady-state noise floor, and computing a measure of spectral flatness associated with the samples within the frame. The method also includes determining that the measure of spectral flatness satisfies a threshold condition, and in response, computing an updated estimate of the steady-state noise floor.

Disclosed embodiments may relate to systems and methods for monitoring and/or mapping noise data from a plurality of noise monitoring devices. In some embodiments, the plurality of noise monitoring devices may include hearing protection devices configured to detect noise, and typically may communicate such noise data (which may also include location) so that the noise data can be pooled. The pooled noise data from the plurality of noise monitoring devices may then be used to the benefit of one or more of such noise monitoring devices.

It is provided with: a target sound vector selecting unit for selecting, from steering vectors acquired in advance and indicating arrival directions of sound with respect to a microphone array including two or more acoustic sensors, a target sound steering vector indicating an arrival direction of target sound; an interference sound vector selecting unit for selecting, from the steering vectors acquired in advance, an interference sound steering vector indicating an arrival direction of interference sound other than the target sound; and a signal processing unit for acquiring, on the basis of two or more observation signals obtained from the microphone array, the target sound steering vector, and the interference sound steering vector, a signal obtained by eliminating the interference sound from the observation signals.

Disclosed is a system, method, and aircraft for controlling acoustic radiation from an aircraft comprising a plurality of rotor systems and a noise controller configured to regulate acoustic radiation from the plurality of rotor systems. The noise controller can be configured to regulate a commanded flight setting from the flight control system and to output a regulated flight setting to the plurality of rotor systems. Based on the regulated flight setting, the plurality of rotor systems are configured to generate, individually and in aggregate, acoustic radiation having a target acoustic behavior. In certain aspects, the noise controller can change the directionality of acoustic radiation from the plurality of rotor systems, or otherwise tune the acoustic radiation to reduce detectability or annoyance.

For example, an apparatus may include an input to receive input information including a Heating, Ventilation and Air Conditioning (HVAC) input including HVAC configuration information corresponding to a configuration of an operation of an HVAC system of a vehicle; a plurality of noise inputs representing acoustic noise at a plurality of noise sensing locations; and a plurality of residual-noise inputs representing acoustic residual-noise at a plurality of residual-noise sensing locations within at least one sound control zone in the vehicle; a controller configured to determine a sound control pattern to control sound within the at least one sound control zone in the vehicle, the controller configured to determine the sound control pattern based on the HVAC input, the plurality of noise inputs and the plurality of residual-noise inputs; and an output to output the sound control pattern to a plurality of acoustic transducers.