A system for generating and injecting acoustic interference signals to mitigate undesired acoustic noise over a target zone. M pickup sensors pick up acoustic noise signals from one or more noise sources in real time and generate M noise signals, M>1. A beam forming network includes M acoustic beam forming modules to process the M noise signals respectively and generate N acoustic interference signals. N acoustic injectors condition, amplify and inject the N acoustic interference signals over the target zone, N>1. Each of the M acoustic beam forming modules includes a 1-to-N distribution network to transform a respective one of the M noise signals into N signals, and N finite-impulse-response filters to perform amplitude and phase weighting on the respective N signals and generate N intermediate signals which are combined respectively with corresponding intermediate signals generated by remaining M1 acoustic beam forming modules to generate the N acoustic interference signals.

Disclosed is an active-noise control device including two passive attenuation earphones each provided with an external microphone, an internal microphone and a loudspeaker. The control device includes a first processing chain having a feedforward filter, a feedback filter and a reconstruction module. The control device includes a second processing chain having a sound source identification module, said second processing chain being implemented in parallel with the first processing chain, and being suitable for parameterizing the first processing chain.

An active noise reducing earphone includes a rigid cup-like shell having an inner surface and an outer surface is provided. The inner surface encompasses a cavity with an opening, and a microphone arrangement is configured to pick up sound with at least one steerable beam-like directivity characteristic, and to provide a first electrical signal that represents the picked-up sound. The earphone further includes an active noise control filter configured to provide, based on the first electrical signal, a second electrical signal, and a speaker disposed in the opening of the cavity and configured to generate sound from the second electrical signal. The active noise control filter has a transfer characteristic that is configured so that noise that travels through the shell from beyond the outer surface to beyond the inner surface is reduced by the sound generated by the speaker.

A quiet zone generation technique for acoustic/audio signals is proposed for mitigation of selected noise or interferences over limited areas in free space by injecting the very acoustic noise, interference, or audio feedback signals via iterative processing, generating quiet zones dynamically. This creates undesired noise-free quiet zones. Optimization loops operating iteratively to electronically process cancellation signals consist of three interconnected functional blocks: (1) an acoustic injection array, consisting of pick-up arrays to obtain the interference signals, beam forming networks for element weighting and/or re-positioning, and array elements for noise injections, (2) a diagnostic network with strategically located probes, and (3) an optimization processor with cost minimization algorithms to calculate element weights for updating.

A method and a system for reducing undesired interference in a target zone. A set of M pickup sensors pick up undesired signals in real time and generate M pickup signals, M being an integer greater than or equal to 1. A beam forming network coupled to the M pickup sensors comprises a receiving beam forming module and a transmitting beam forming module. The receiving beam forming module receives the M pickup signals and generates K beam signals, K being an integer greater than or equal to 1. The transmitting beam forming module receives the K beam signals and generates N interference signals, N being an integer greater than 1. A set of N injectors coupled to the transmitting beam forming module receives the N interference signals, respectively, and radiates the N interference signals to the target zone.

According to the present disclosure there is provided an active acoustic control system for controlling an acoustic signal propagating along a propagation path, the system comprising: an active control unit configured to: receive information from a first sensor arrangement, the information related to the acoustic signal propagating along the propagation path; generate a control signal for controlling the acoustic signal based on the information from the first sensor arrangement, by being arranged to control: a first control source arrangement comprising a finite 2D array of first control sources for generating a first control signal for controlling a first component of the acoustic signal.

According to the present disclosure there is provided an active acoustic control system for controlling an acoustic signal propagating along a propagation path, the system comprising: an active control unit configured to: receive information from a first sensor arrangement, the information related to the acoustic signal propagating along the propagation path; generate a control signal for controlling the acoustic signal based on the information from the first sensor arrangement, by being arranged to independently control: a first control source arrangement for generating a first control signal to control a first component of the acoustic signal; and a second control source arrangement for generating a second control signal to control a second component of the acoustic signal.

A system for reducing undesired interference in a target zone is disclosed. The system comprises a set of M pickup sensors, a beam forming network coupled to the M pickup sensors, and a set of N injectors coupled to the beam forming network. The M pickup sensors pick up undesired signals in real time and generate M pickup signals, M being an integer greater than or equal to 1. The beam forming network comprises a set of M beam forming modules. Each of the M beam forming modules receives a respective one of the M pickup signals and generates N intermediate signals, N being an integer greater than 1. The N intermediate signals generated by each of the M beam forming modules are combined correspondingly with remaining intermediate signals generated by remaining M1 beam forming modules to generate N interference signals. The N injectors receive and radiate the N interference signals to the target zone.

A method and system for a noise cancellation comprises an amplifier in communication with the three or more speakers disposed in an area. A system controller produces a driver signal for each of the speakers in response to a signal from at least one microphone detecting sound in the area and communicates the driver signals to the amplifier. The amplifier drives each speaker with the driver signal produced for that speaker. In response to the driver signals, the speakers emit sound that combined produces a substantially uniform sound pressure field for a particular zone within the area. The substantially uniform sound pressure field produced by the speakers has a magnitude and phase adapted to attenuate a noise field in the area corresponding to the sound detected by the at least one microphone.

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.