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.

Improved adaptive feedback cancellation may be used to improve performance of audio amplification systems, such as hearing assistance devices, sound reinforcement systems, telephony, and other acoustic amplification and reproduction systems. This adaptive feedback cancellation allows a significant increase in the maximum stable gain of the amplification system, such as by increasing gain while reducing or eliminating feedback. This improves the audibility provided by an audio amplification system. This may provide particular improvements for hearing assistance devices that include open fittings or otherwise have substantial acoustic leakage. This adaptive feedback cancellation provides additional protection from a dynamically changing acoustic leakage by continually updating itself to model the changes, thereby providing increased gain while reducing or eliminating feedback.

In-car communication and hands-free talking with good sound quality are realized. An echo cancelation apparatus (4) is for use in a vehicle in which microphones (M1, M2) and loudspeakers (S1, S2) are disposed in acoustic regions (100, 200). A loudspeaker (S1) and a microphone (M1) are disposed in a first acoustic region (100), and a loudspeaker (S2) and a microphone (M2) are disposed in a second acoustic region (200). An acoustic signal picked up by the microphone (M1) disposed in the first acoustic region (100) is emitted from the loudspeaker (S2) disposed in the second acoustic region (200). An acoustic signal picked up by the microphone (M2) disposed in the second acoustic region (200) is emitted from the loudspeaker (S1) disposed in the first acoustic region (100). The microphone (M1) is designed to hardly collect a sound emitted from the loudspeaker (S2).

An active control method for filtered reference affine projection sign algorithm based on variable step size includes: S1, acquiring impulse noise signals and transmitting the signals to control filters; S2, transmitting the impulse noise signals by the control filters to post filters; S3, generating cancellation signals of the impulse noise signals by the post filters according to the impulse noise signals and internal active control algorithms, and transmitting the cancellation signals to a speaker; S4, sending out the cancellation signal by the speaker to superimpose with the impulse noise signals to cancel the impulse noise signal. A convex combination structure and a variable step size strategy are adopted, and by adjusting step size coefficients in the control filter structure, convergence speed of algorithm is controlled, contradiction between convergence speed and steady-state error is coordinated, convergence performance of control algorithm to impulse noises is improved, and impulse noises are effectively controlled.

An active noise reduction device includes: a reference signal input terminal that receives a reference signal from a reference signal source attached to an automobile; a simulated vibration transfer characteristics filter unit that generates a second signal by correcting, using simulated vibration transfer characteristics, a first signal for outputting, from a loudspeaker attached to the automobile, a sound different from a canceling sound, the simulated vibration transfer characteristics simulating vibration transfer characteristics from the loudspeaker to the reference signal source; a first subtracter that outputs a corrected reference signal obtained by subtracting the second signal generated, from the reference signal received by the reference signal input terminal; and an adaptive filter unit that applies an adaptive filter to the corrected reference signal outputted from the first subtracter to generate a canceling signal to be used to output the canceling sound.

[Object] A control apparatus according to an embodiment of the present technology includes a tactile control section and an audio control section. The tactile control section generates, on the basis of a tactile signal for tactile presentation, a tactile control signal for driving a tactile presentation unit. The audio control section generates, on the basis of a first audio signal and a second audio signal, an audio control signal for driving an audio output unit, the second audio signal containing sound components that are in an opposite phase to sound generated on the basis of the tactile signal and generated from the tactile presentation unit.

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.

Described herein are system and method embodiments for adaptive noise control for headphones, specifically for open-ear headphones. A leakage detection module in an ambient sound control (ASC) circuit implements leakage detection to determine a leakage mode. Based on the determined leakage mode, an ASC profile may create, select or modify an ASC profile for the ASC circuit to operate. Pilot tone, ambient noise, or audio playback may be used respectively or in combination for leakage detection. Experimental results show that embodiments of adaptive ASC approach may achieve improved performance compared to a default ASC, especially under loose fitting of an earphone.

The application describes techniques for howling detection. A howling detector is described that is configured to receive an input signal and to determine measure of the linearity of a logarithmic representation of the energy of the input signal. In some examples, this triggers gain adjustment (e.g. of a noise control unit) and, in some further examples, the amount of the gain adjustment may be based on an estimation of the maximum stable gain of a noise control unit.

An earpiece (100) and acoustic management module (300) for in-ear canal echo suppression control suitable is provided. The earpiece can include an Ambient Sound Microphone (111) to capture ambient sound, an Ear Canal Receiver (125) to deliver audio content to an ear canal, an Ear Canal Microphone (123) configured to capture internal sound, and a processor (121) to generate a voice activity level (622) and suppress an echo of spoken voice in the electronic internal signal, and mix an electronic ambient signal with an electronic internal signal in a ratio dependent on the voice activity level and a background noise level to produce a mixed signal (323) that is delivered to the ear canal (131).