Systems and methods include a digital control module that receives and processes audio data for output through a loudspeaker. An analog block receives the audio data and the power control signal and amplifies the audio data for output. A first processing path includes a buffer to delay the audio data, a first component to combine the buffered audio data and anti-noise. A second processing path includes an absolute value block to receive the audio data and an envelope detector to receive the absolute value data and generate a maximum value for the envelope. An anti-noise path includes an absolute value block configured to determine an anti-noise absolute value which is combined with the absolute value anti-noise data. A power generator receives the output from the envelope detector and updates a power level to approximate a minimum powered needed to process the audio signal.

An active noise cancellation system includes a sensor operable to sense environmental noise and generate a corresponding reference signal, a fixed noise cancellation filter including a predetermined model of the active noise cancellation system operable to generate an anti-noise signal, and a tunable noise cancellation filter operable to modify the anti-noise signal in accordance with stored coefficients, wherein the tunable noise cancellation filter is further operable to modify the stored coefficients in real-time based on user feedback and generate a tuned anti-noise signal that models tunable deviations from the predetermined noise model. A graphical user interface is operable to receive user adjustments of tunable parameters in real-time, the tunable parameters corresponding to at least one of the stored coefficients.

A system for cancelling an internally generated noise includes a processing device disposed on a patient. The processing device includes a sensor configured to record a pulse sound waveform generated by a pulse of the patient and at least one waveform processing circuit configured to output a cancellation sound waveform based on the recorded pulse sound waveform. The system also includes a sound output device coupled to the processing device. The sound output device is configured to output the cancellation sound waveform to cancel or minimize the pulse sound waveform corresponding to the internally generated noise.

Vertical take-off and landing (VTOL) aircraft can provide opportunities to incorporate aerial transportation into transportation networks for cities and metropolitan areas. However, VTOL aircraft may be noisy. To accommodate this, the aircraft may utilize onboard sensors, offboard sensing, network, and predictive temporal data for noise signature mitigation. By building a composite understanding of real data offboard the aircraft, the aircraft can make adjustments to the way it is flying and verify this against a predicted noise signature (via computational methods) to reduce environmental impact. This might be realized via a change in translative speed, propeller speed, or choices in propulsor usage (e.g., a quiet propulsor vs. a high thrust, noisier propulsor). These noise mitigation actions may also be decided at the network level rather than the vehicle level to balance concerns across a city and relieve computing constraints on the aircraft.

Devices, methods, systems, and media for selectively cancelling sounds at a listener's location are described. Sound sources are identified in the listener's environment using microphones and/or remote devices associated with specific sound sources. A user is presented with information identifying the sound sources, including spatial information, and prompting the user to select one or more of the sound sources. After the user designates a sound source as noise, microphones are used to monitor for sound originating from the designated sound source, and the audio information captured by the microphones is processed to generate an anti-noise signal presented to the listener to cancel sounds originating from the selected sound source. A user may designate multiple sound sources as noise and leave other sound sources unfiltered. The techniques may be used in single-listener and multi-listener applications, and in listening and speaking applications.

An ANC system includes an AD converter which performs AD conversion on an external noise signal, an ANC signal generator which generates an ANC signal for canceling a noise component arriving at the ears of a user based on an output signal of the AD converter, and a level detector which detects a level of the output signal and causes the ANC signal generator to power down in response to the level. The level detector measures a time for which the level is equal to or less than a predetermined first threshold value, causes the ANC signal generator or a portion of blocks of the AD converter to power down after the measured time exceeds a predetermined value, and causes the ANC signal generator or a portion of blocks of the AD converter to return from the power down when the level exceeds a predetermined second threshold value.

Adaptive filters output a cancellation sound from a speaker, a selector selects outputs of a plurality of auxiliary filters each corresponding to different positions, a subtractor subtracts the selected output from the output of the microphone and outputs the subtracted output to the adaptive filter as an error signal, and a position detection device detects a position of a head of a user. A transfer function estimated so that the error signal becomes 0 when noise is canceled at the corresponding position is preset in the auxiliary filter. When the auxiliary filter corresponding to the position close to the head of the user changes, the switching control unit stepwise increases the frequency with which the output of the auxiliary filter is selected by the selector to 100%.

A road noise-cancellation system, comprising: an actuator disposed in a vehicle cabin; a controller comprising a processor and non-volatile memory, the controller being programmed to: generate a noise-cancellation signal with a noise-cancellation filter including a first plurality of coefficients, the noise-cancellation signal being based on the first plurality of coefficients, the noise-cancellation signal being transduced by the actuator to generate 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; adjust the first plurality of coefficients of the noise-cancellation filter based on one or more input signals to provide a second plurality of coefficients; store the second plurality of coefficients in the non-volatile memory during a shutdown sequence or at the end of an interval; and restore the second plurality of coefficients from non-volatile memory to the noise-cancellation filter after (i) startup or (ii) determining that a third plurality of coefficients, provided by a second adjustment, are divergent or unstable.

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.

According to an example embodiment, an apparatus for active cancellation of sound and vibration is provided, the apparatus including sound and vibration generation components for jointly producing vibration and sound under control of a driving signal provided as input thereto, the components being arranged inside a padding to generate mechanical vibration that is perceivable as a vibration and sound on at least one outer surface of the padding and to radiate a sound through the at least one outer surface of the padding, a feedback unit for providing feedback information that is indicative of acoustic energy of sound and vibration inside the padding, and a drivert for generating the driving signal in dependence of the feedback information so as to reduce energy of ambient sound and vibration induced inside the padding due to one or more external sources of sound and vibration.