Methods and systems for reducing a pressure wave are provided. In an exemplary embodiment, a motor vehicle comprises a cabin and a receiver positioned to detect an input pressure wave within the cabin and produce an input signal. A fan with a blade having a variable pitch is positioned within the vehicle where the fan is audible within the cabin. A processor is in communication with the receiver and the fan, where the processor is configured to receive the input signal and determine an input frequency and an input phase. The processor is further configured to instruct the fan to control a pitch of the blade to produce a cancellation pressure wave with a cancellation frequency that is about the same as the input frequency and a cancellation phase that is about 180° out of phase with the input phase.

An ASC apparatus, which actively generates a sound effect inside a cabin of a vehicle provided with an internal combustion engine and an electric motor as driving sources, includes: a reference signal generating unit which generates a harmonic reference signal based on a vehicle-speed-corresponding frequency, being a frequency based on a vehicle speed, by referring to waveform data; a driver seat speaker which outputs a sound including the sound effect; and a signal processing unit which generates a control signal that forms the sound effect by multiplying the reference signal by a sound effect gain related to the reference signal, and outputs the control signal to the driver seat speaker. The signal processing unit sets the sound effect gain based on a state of charge of a storage battery.

A system for generating silent zones at a listening position comprises a first loudspeaker disposed at a first position and configured to radiate sound that corresponds to a sound signal. A first microphone picks up noise radiated by a noise source to the listening position and generates a first microphone signal. A second loudspeaker disposed at a second position that radiates sound. A second microphone that generates a second microphone signal. A third microphone disposed at a third position that generates a third microphone signal. An active noise cancellation (ANC) controller that receives the third microphone signal and at least one of the first and second microphone signals and that provides a loudspeaker input signal. A distance between the third position and the first position equals a distance between the third position and the second position such that the first, second and third microphones form corners of an isosceles triangle.

In one example, a headset comprises a microphone; an earpiece that is configured to output audio based on one or more of the following: a first audio signal from a connected host device and associated with an application type and a second audio signal from the microphone, when present; a noise reduction module that is configured to reduce ambient noise; a speech detection module that is configured to detect whether a headset user is talking; a voice pass-through module that is configured to pass external voices captured with the microphone as the second audio signal to the earpiece, when activated; and a controller that is configured to activate the voice pass-through module in response to the speech detection module detecting the headset user talking, when uplink audio is off.

The present technology relates to a particular-sound detector and method, and a program that make it possible to improve the performance of detecting particular sounds.

The particular-sound detector includes a particular-sound detecting section that detects a particular sound on a basis of a plurality of audio signals obtained by collecting sounds by a plurality of microphones provided to a wearable device. In addition, the plurality of the microphones includes two microphones that are equidistant at least from a sound source of the particular sound, and one microphone arranged at a predetermined position. The present technology can be applied to headphones.

Various implementations include systems for processing inner microphone audio signals. In particular implementations, a system includes an external microphone configured to be acoustically coupled to an environment outside an ear canal of a user; an inner microphone configured to be acoustically coupled to an environment inside the ear canal of the user; and an adaptive noise cancelation system configured to process an internal signal captured by the inner microphone and generate a noise reduced internal signal, wherein the noise reduced internal signal is adaptively generated in response to an external signal captured by the external microphone.

Active noise cancellation may be provided by a variety of systems, methods and techniques. General aspects, for example, include an active noise cancellation system, a controller for an active noise cancellation system, and/or a method of generating an anti-noise signal. In one example aspect, an active noise cancellation system for an aircraft In-flight entertainment system may include at least one input device, a processing means, and an output. The input device may be associated with a seat on the aircraft and adapted to receive an input representative of an ambient noise in the vicinity of the seat. The processing means may be adapted to process the input to produce an output signal adapted to reduce the ambient noise in volume associated with the seat. The output may be adapted to transmit an output signal to at least one driver, which is adapted to transmit the output signal to a user.

An active noise reduction (ANR) earphone system includes a feedback microphone for detecting noise, feedback circuitry, responsive to the feedback microphone, for applying a digital filter K.sub.fb to an output of the feedback microphone to produce an antinoise signal, an electroacoustic driver for transducing the antinoise signal into acoustic energy, a housing supporting the feedback microphone and the driver near the entrance to the ear canal, and an ear tip for coupling the housing to the external anatomical structures of a first ear of a user and positioning the housing to provide a consistent acoustic coupling of the feedback microphone and the driver to the ear canal of the first ear. The acoustic coupling includes a tube of air defined by the combination of the housing and ear tip, having a length L and effective cross-sectional area A such that the ratio L/A is less than 0.6 m.sup.−1.

An active noise control arrangement has a signal input (SI), a microphone input (MI), a signal output (SO) and a digital interface (DI). A signal processing block (SP) coupled to the microphone input (MI) by means of an amplifier (MA) has a digitally adjustable gain and comprises combining means (CM) and a filter (TP). The signal processing block (SP) is configured to generate an output signal at the signal output (SO) as a function of an input signal at the signal input (SI) and an amplified microphone signal. A control block (CB) is coupled to the digital interface (DI) and configured to adjust the gain of the amplifier (MA).

An attenuation device for attenuating sound waves, and a corresponding system and method, generated by a source emitting sound waves having frequencies between f1 and f2 and wherein the pressure levels are between n1 and n2. The attenuation device comprising at least one acoustic absorber comprising at least one non-linear membrane; the attenuation device being configured in such a way that the first face of the absorber is in acoustic communication with the source. The attenuation device also comprises at least one coupling element for coupling the second face with the source, the coupling element being configured to transmit to the second face sound waves according to the sound waves emitted by the source, and of which the phase and/or the amplitude leads to a pressure differential of the sound waves arriving respectively on the first and second face at the same time.