The present disclosure is directed to controlling, reducing, and/or altering sound generated by an aerial vehicle, such as an unmanned aerial vehicle (UAV), while the aerial vehicle is airborne. For example, one or more transducers, such as piezoelectric thin-film transducers, or carbon nanotube transducers may be applied or incorporated into or on the surface of propeller blades that are used to aerially navigate the aerial vehicle. As the propeller blade rotates and generates sound, the transducers may be activated to generate one or more anti-sounds that cancel, reduce, or otherwise modify the sound generated by the rotation of the propeller blade. The anti-sound combines with the sound and causes interference such that the combined, or net-effect, is an overall cancellation, reduction, or other modification of the sound.

A noise cancellation method and system comprises a system controller that produces a command signal in response to a signal from at least one microphone detecting sound in an area. The system controller includes an arrayed speaker controller for producing a driver signal for each speaker in response to the command signal such that combined sound emitted by the speakers in response to the driver signals produces a substantially uniform sound pressure field adapted to attenuate a noise field corresponding to the sound detected by the at least one microphone. The system controller includes an in-phase speaker controller for producing a common in-phase driver signal for all speakers in response to the command signal and a signal director module for proportioning the command signal between the arrayed and in-phase speaker controllers in response to a magnitude of voltage associated with driving the speakers in accordance with the command signal.

An acoustic conversion device for an active noise control including a protection member is provided. Since the protection member hides an entire opening, all of water and foreign matters which pass through the opening arrive at an upper surface of the protection member. Further, since the protection member hides the entire speaker unit, it is possible to protect a vibration plate of the speaker unit from water and foreign matters which drop from the protection member. Therefore, water and foreign matters are prevented from adhering to the vibration plate, it is possible to prevent lowest resonance frequency from being varied, emitted sound can be less prone to be deviated from opposite phase of noise, and it is possible to effectively suppress or remove noise.

An acoustic conversion device for an active noise control is provided. The acoustic conversion device can effectively suppress or remove noise by controlling variation in a lowest resonance frequency. A volume of a closed space is smaller than an equivalent compliance air volume of a speaker unit. Therefore, motion of a vibration plate, an edge and a damper is suppressed, it is possible to restrain the edge and the damper from being deteriorated with time, variation in lowest resonance frequency can be suppressed, phase of emitted sound can be less prone to be deviated from opposite phase of noise, and it is possible to effectively suppress or remove noise.

The present invention provides for a surface acoustic transducer optimally structured to produce sound within an aircraft cabin by vibrating the interior cabin walls. Specifically, the surface acoustic transducer comprises a primary assembly comprising a voice coil assembly having a voice coil former and wire, and a transducer housing for retaining said primary assembly and a magnet therein such in movable relations. The present surface acoustic transducer may further include a spider structured to provide an improved excursion. An external housing may additionally be provided comprising a rigid retaining wall for protecting the surface acoustic transducer from potential externally applied forces and a malleable excursion cover allowing for an excursion of the primary assembly thereof.

In one embodiment, a device includes at least one transducer configured to vibrate within a first frequency range to generate a signal audible by a wearer of the device. The device includes the first material, which has an acoustic impedance at one or more frequencies within the first frequency range that is substantially similar to an acoustic impedance of the wearer's skin at the one or more frequencies. The device includes a second material that has an acoustic impedance at one or more frequencies within the first frequency range that substantially differs from an acoustic impedance of an environment of the device.

A wearable computing device can receive, via at least one input transducer, a first audio signal associated with ambient sound from an environment of the device. The device can then process the first audio signal so as to determine a second audio signal that is out of phase with the first audio signal and effective to substantially cancel at least a portion of the first audio signal. The device may then generate a noise-cancelling audio signal based on the second audio signal, based on a third audio signal, and based on one or more wearer-specific parameters, where the third audio signal is representative of a sound to be provided by the device. The device may then cause a bone conduction transducer (BCT) to vibrate so as to provide to an ear a noise-cancelling sound effective to substantially cancel at least a portion of the ambient sound.

In one embodiment, a computer-program product embodied in a non-transitory computer readable medium that is programmed for performing active vibration cancellation (AVC) in a moving vessel is provided. The computer-program product includes instructions to receive a first signal indicative of vibrations that are exhibited on at least one passenger in a cabin of the moving vessel and to determine a resonant frequency of the vibrations that are exhibited on the at least one passenger based on the first signal. The computer-program product further includes instructions to generate a first anti-wave signal based on the resonant frequency and to drive at least one haptic actuator that is positioned proximate to the at least one passenger in the cabin with the first anti-wave signal to minimize motion sickness for the at least one passenger caused by the vibrations that are exhibited on the at least one passenger in the vessel.

A technology is provided that reduces noise heard when a user sits in a seat of an aircraft, without using earphones or headphones. A sound system includes: a control system that generates a control signal for canceling noise in a place close to a head of a user using a seat of an aircraft, from a signal of the noise (noise signal); and a noise-cancellation speaker system including speaker units that emit sound based on the control signal (first noise-cancellation speaker unit, . . . , M-th noise-cancellation speaker unit), the noise-cancellation speaker system being installed at the place close to the head of the user using the seat, wherein assuming that a direction in which the m-th noise-cancellation speaker unit faces the user is an m-th noise-cancellation user direction, the m-th noise-cancellation speaker unit is disposed such that sound emitted from the m-th noise-cancellation speaker unit in the m-th noise-cancellation user direction is canceled in a place other than the place close to the head of the user using the seat, due to bending around of sound emitted from the m-th noise-cancellation speaker unit in an opposite direction to the m-th noise-cancellation user direction.

A noise cancellation method and system comprises a system controller that produces a command signal in response to a signal from at least one microphone detecting sound in an area. The system controller includes an arrayed speaker controller for producing a driver signal for each speaker in response to the command signal such that combined sound emitted by the speakers in response to the driver signals produces a substantially uniform sound pressure field adapted to attenuate a noise field corresponding to the sound detected by the at least one microphone. The system controller includes an in-phase speaker controller for producing a common in-phase driver signal for all speakers in response to the command signal and a signal director module for proportioning the command signal between the arrayed and in-phase speaker controllers in response to a magnitude of voltage associated with driving the speakers in accordance with the command signal.