A noise reduction device includes a processor that converts a noise signal collected by a microphone disposed in a control space into a noise signal in a frequency domain, a storage that stores the converted noise signal in the frequency domain as a reference signal, and a signal generator that generates a noise reduction signal for reducing the noise signal collected by the microphone at a control position of the control space. The processor determines whether or not the noise signal is non-stationary noise based on a frequency characteristic of the converted noise signal in the frequency domain and a frequency characteristic of the reference signal. When it is determined that the noise signal is the non-stationary noise, the processor controls the signal generator so as to cancel generation of the noise reduction signal.

In a method that reduces the occurrence of acoustic feedback in a hearing device, a first wearing situation is created that determines a positioning of the hearing device relative to the wearer. For the first wearing situation, a first usage situation is created being a body movement of the wearer of the hearing device and/or a relative position of an external object relative to the body of the wearer. A first number of frequency-resolved curves of a feedback tendency of the hearing device are determined for the first use situation. A first criticality measure is ascertained based on the frequency-resolved curve for the first use situation that contains information on a frequency range that is critical with respect to an occurrence of acoustic feedback and a corresponding relative probability of acoustic feedback, and a target is established for adapting a hearing device parameter based on the first criticality measure.

An in-vehicle voice recognition apparatus capable of recognizing user voice more correctly by removing sound generated in a vehicle from sound input to a microphone, and a method of controlling the same are disclosed. The in-vehicle voice recognition apparatus according to an embodiment of the present disclosure includes a central processing unit configured to output a media signal, a digital signal processor configured to receive the media signal from the central processing unit and to convert the media signal into an analog signal, and an eco cancellation hardware connected to the digital signal processor and configured to receive the analog signal, to acquire a first final media output on the basis of the analog signal and to acquire a voice command from a sound input through a microphone on the basis of the first final media output.

This document describes a method that includes receiving a driver signal for an acoustic transducer of an acoustic device. The method also includes receiving a signal from a microphone of the acoustic device, and, processing the driver signal through a filter to provide a reference signal. The filter has a transfer function associated with a condition of the acoustic device. The method also includes comparing the signal to the reference signal to determine whether the signal has a threshold similarity to the reference signal, and, indicating the condition of the acoustic device in respond to the determined threshold similarity.

With the noise reduction device (300), in identifying an acoustic transfer function that includes a path from the control speaker (340) to the error microphone (350) or the noise microphone (320) by outputting an identification sound from the control speaker (340) and detecting the identification sound with the error microphone (350) or the noise microphone (320), the identification controller (338) is configured to identify the acoustic transfer function by generating the identification sound from the white noise generator (337) when the seat detector (582) has detected that the seat is in the actual usage state for noise reduction.

A processing module for a noise control circuit may include a howling detector configured to receive an input signal and to determine a linearity metric based on the input signal, the linearity metric comprising a measure of the linearity of a logarithmic representation of the energy of the input signal. The processing module may also include a gain adjuster configured to adjust the gain of a noise control unit.

An in-vehicle voice recognition apparatus capable of recognizing user voice more correctly by removing sound generated in a vehicle from sound input to a microphone, and a method of controlling the same are disclosed. The in-vehicle voice recognition apparatus according to an embodiment of the present disclosure includes a central processing unit configured to output a media signal, a digital signal processor configured to receive the media signal from the central processing unit and to convert the media signal into an analog signal, and an eco cancellation hardware connected to the digital signal processor and configured to receive the analog signal, to acquire a first final media output on the basis of the analog signal and to acquire a voice command from a sound input through a microphone on the basis of the first final media output.

In a signal processing device, a signal processing method, a recording medium, and a rangehood apparatus, a filter coefficient is set in a sound cancelling filter, and the sound cancelling filter outputs a cancellation signal. A coefficient calculator calculates a first filter coefficient. An oscillation suppressor calculates a second filter coefficient by applying a window function to the first filter coefficient to set the second filter coefficient as the filter coefficient.

A fixture for calibrating an active noise canceling (ANC) earphone, the calibration fixture including an ear model and an acoustic path. The ear model is configured to support an ANC earphone and includes an ear canal extending from an outer end of the ear canal to an inner end of the ear canal. The acoustic path is external to the ear canal and extends from, at a first end of the acoustic path, the inner end of the ear canal of the ear model to an opposite, second end of the acoustic path. The acoustic path is configured to transmit a mechanical sound wave received from the inner end of the ear canal to a region external to the ear model and adjacent the outer end of the ear canal.

The application describes techniques for howling detection. A processing module for a noise control circuit is described. The processing module comprises a howling detector configured to receive an input signal and to determine a log-linearity metric based on the input signal. Gain adjustment of the noise control unit following the detection of howling is also described, wherein the amount of gain adjustment may be based on an estimation of the maximum stable gain of the noise control unit.