A method of using an acoustic resonator including receiving at a first stage of a resonator an incoming acoustic wave. The method further includes resonating the incoming wave with a flexible membrane, a taper of the flexible membrane, and a cavity of a first stage, thereby producing synergistic effect on a resulting acoustic resonance. Additionally, the method includes transforming an acoustic energy associated with the incoming acoustic wave into an elastic energy, wherein the elastic energy is channeled through the flexible membrane, thereby reducing an intensity of the incoming acoustic wave and resulting in a first reduced incoming acoustic wave. Further the method includes transferring the first reduced incoming acoustic wave through a hole of a neck of the flexible membrane. The method also includes transferring a first pressure wave caused by a perturbation in the flexible membrane into a second stage, thereby producing a second acoustic wave.

A first cancellation signal output from a first speaker cancels noise at a first cancellation point, which is a typical position of the right ear of a user, together with a second cancellation signal output from a second speaker. In addition, the second cancellation signal output from the second speaker cancels noise at a second cancellation point, which is a typical position of the left ear of the user, together with the first cancellation signal output from the first speaker. The first speaker and the second speaker are arranged side by side on a second line segment, which passes through the midpoint of a first line segment connecting the first cancellation point and the second cancellation point to each other and is perpendicular to the first line segment, and a range where the relationship between noise and the first cancellation signal and the second cancellation signal is the same as that at the cancellation point is extended.

In at least one embodiment, an active noise cancellation system. The system includes a first controller, a data bus, and a second controller. The first controller receives first information from a plurality of noise sensing devices and second information from an audio system. The first controller employs a time division multiplexing scheme to generate a multiplexed stream of data including the first information and the second information. The data bus transmits the multiplexed stream of data on a single data channel. The second controller receives the multiplexed stream of data on the single data channel and separates the first information from the second information on the multiplexed stream of data to perform ANC functionality.

An earphone system comprises at least one earphone configured to be inserted in an ear of a user, wherein each of the at least one earphone comprises at least one sound reproduction unit, and a remote unit that is separate from each of the at least one earphone, wherein the remote unit comprises at least one microphone configured to capture ambient sound. The remote unit is configured to evaluate, analyze and/or process the ambient sound captured by the at least one microphone, to determine one or more of at least one ambient sound parameter, at least one control parameter, and at least one control command, based at least on the evaluation, analysis and/or processing of the ambient sound, and to send the at least one ambient sound parameter, the at least one control parameter and/or the at least one control command to the at least one earphone.

Proposed is an earplug that can effectively reduce high-frequency noise using a metasurface. The high-frequency noise filtering earplug using a metasurface according to an embodiment of the present disclosure may include an eartip with an internal passage, an interference attenuation module having a damping passage for reducing noise and a first reflective cavity that is connected to the damping passage and reflects incident sound waves and transmits the sound waves to the damping passage, and a connecting tube installed between the eartip and the interference attenuation module to connect the internal passage and the damping passage to each other.

A helmet including an active noise cancellation (ANC) system which includes a first reference microphone for measuring sound pressure at a first location on a first side of the helmet, the first location between a defined spatial region and a first source of sound and a second reference microphone for measuring sound pressure at a second location, different to the first location, on the first side. The second location is between the defined spatial region and a second source of sound. A loud speaker is provided in or adjacent to the defined spatial region. A control unit determines, based on output signals from the first and second microphones, a drive signal for driving the loudspeaker to generate a sound signal that at least partially attenuates, in the defined spatial region and in the first frequency range, the sound signals from the first and second noise sources.

The improved active noise cancellation system for forced air heating or cooling systems onboard aircraft employs a duct having a proximal end coupled to the fan unit to entrain the airflow stream in the direction of a distal end of the duct. A reference sensor is positioned within the proximal end of the duct. A means is provided for injecting an audio frequency control signal into the airflow stream in a manner that does not substantially impede the airflow stream. An error sensor is positioned at the distal end of the duct where it is responsive to sounds carried by the airflow stream, including the audio frequency control signal. An electronic circuit coupled to the reference sensor and to the error sensor supplies a noise abating control signal to energize the control transducer and thereby substantially reduce at least one noise harmonic of the fan unit through destructive interference.

A control system provides centralized active noise control (ANC) and active vibration control (AVC) through a digital network. The control system includes a controller, an audio sub-system, and a vibration sub-system. The audio-sub system includes at least one sound monitoring component and at least one sound outputting component. The vibration sub-system includes at least one vibration monitoring component and at least one vibration actuating component. The controller and the sub-systems are interconnected through the digital network. The controller controls the sub-systems through the digital network to perform the ANC and AVC functions in a holistic approach.

An audio system attachable to a computer includes a sound reproduction device for producing audible sound from audio signals. The sound reproduction device includes a radio tuner and a powered speaker. The audio system further includes a connector for connecting the sound reproduction device with a computer. The computer provides audio signals from a plurality of sources, the sources including a computer CD player, digitally encoded computer files stored on the computer, and a computer network connected to the computer. The sound reproduction device further includes control buttons for controlling at least one of the computer CD player, the digitally encoded computer files and the computer network.

A headset cup having a front cavity and a rear cavity separated by a driver, with a mass port tube connected to the rear port to present a reactive acoustic impedance to the rear cavity, in parallel with a resistive port, the total acoustic response of the rear cavity remaining linear at high power levels. In some embodiments, the mass port tube is made of metal, while the headset cup is otherwise made of plastic.