Abstract: In order to enable noises entering the ear from random directions to be muted without wearing headphones, this muting device is provided with: a super-directional microphone that detects noises in spot areas around the ear at pinpoints; and an ultrasonic speaker that modulates and outputs a carrier signal supplied by a transmitter according to noise signals detected by the super-directional microphone. Furthermore, an adaptive filter is provided, and the adaptive filter supplies noise signals with the opposite phase to noises detected by the super-direction microphone, and transmits an ultrasonic signal from the ultrasonic speaker toward the eardrum of a human.

Abstract: Methods and apparatus are provided for controlling noise in a compartment. The audio system includes an error microphone configured to receive sounds and generate an error signal corresponding to the received sounds. A processor in communication with the error microphone is configured receive the error signal from the error microphone and generate a noise-canceling signal based at least in part on the error signal and an acoustic transfer function. The audio system also includes a loudspeaker in communication with the processor to receive the noise-canceling signal and produce a noise-canceling sound wave based on the noise-canceling signal. The processor is also configured to receive at least one audio signal different from the error signal and to modify the acoustic transfer function utilizing the at least one audio signal.

Abstract: A control signal filter 2 receives a sound source signal determined by a control frequency specified in accordance with the vibration/noise source that produces vibration/noise, and outputs a control signal. A filter coefficient update unit 4 updates coefficients of the control signal filter 2 in response to a sound source signal and an error signal. A disturbance detector 6 outputs a disturbance detection result in response to the error signal and an estimated secondary vibration/noise signal. An update controller 7 adjusts an update step of the filter coefficient update unit 4 in accordance with the disturbance detection result.

Abstract: Acoustic noise in an audio signal is reduced by calculating a speech probability presence (SPP) factor using minimum mean square error (MMSE). The SPP factor, which has a value typically ranging between zero and one, is modified or warped responsive to a value obtained from the evaluation of a sigmoid function, the shape of which is determined by a signal-to-noise ratio (SNR), which is obtained by an evaluation of the signal energy and noise energy output from a microphone over time. The shape and aggressiveness of the sigmoid function is determined using an extrinsically-determined SNR, not determined by the MMSE determination.

Abstract: A reference signal generating unit of an active-noise-reduction device of the present invention outputs a referencing signal having a correlation with a vibration to an adaptive filter unit. A filter coefficient update unit receives an input of an error signal, and successively updates a filter coefficient of the adaptive filter unit. The error signal is generated by a cancelling sound based on the output of the adaptive filter unit and noise. The detection unit detects a filter coefficient of the filter coefficient update unit, and determines a size of the output of the adaptive filter unit. Then, the amplitude of the cancelling sound is adjusted based on the size of the output of the adaptive filter unit estimated by the detection unit.

Abstract: An active noise reduction earphone includes a speaker, a plurality of microphones and a feedback system. Each microphone is displaced from the speaker and the other microphones, and each microphone generates a microphone signal responsive to received acoustic noise. The feedback system receives a combination of the microphone signals and generates an inverse noise signal that is applied to the speaker. The speaker generates an inverse acoustic noise signal that substantially cancels the acoustic noise signal at a predetermined location relative to the speaker and the microphones. The feedback system can include a microphone signal combiner in communication with the microphones. The microphone signal combiner generates a signal that may be a sum or weighted sum of the microphone signals and can be used to generate the inverse noise signal. The earphone has an increased noise reduction bandwidth and improved cancellation capability relative to conventional earphones.

Abstract: The present invention discloses a speech enhancement method and device for mobile phones. By the method and device provided by the present invention, the mobile phone holding state of a user is detected when the user is talking on the phone, so that different denoising solutions will be employed according to the state of the user in holding the mobile phone. When the user holds the mobile phone normally, a solution integrating multi-microphone denoising and single-microphone denoising will be employed to effectively suppress both the steady noise and the non-steady noise; and when the user holds the mobile phone abnormally, a solution of single-microphone denoising will be employed only to suppress the steady noise. The distortion of speech by multi-microphone denoising is avoided, and the speech quality is ensured.

Abstract: A system utilizing two pairs of microphones for noise suppression. Primary and secondary microphones may be positioned closely spaced to each other to provide acoustic signals used to achieve noise cancellation/suppression. An additional, tertiary microphone may be spaced with respect to either the primary microphone or the secondary microphone in a spread-microphone configuration for deriving level cues from audio signals provided by the tertiary and the primary or secondary microphone. The level cues are expressed via a level difference used to determine one or more cluster tracking control signal(s). The level difference-based cluster tracking signals are used to control adaptation of noise suppression. A noise cancelled primary acoustic signal and level difference-based cluster tracking control signals are used during post filtering to adaptively generate a mask to be applied to a speech estimate signal.

Abstract: A method and apparatus for providing privacy for telephone conversations over communication networks is disclosed. For example, a telephony endpoint device comprises a microphone for receiving an audio signal and a gain boost circuit, coupled to the microphone, for applying a gain boost to the audio signal. The telephony endpoint device also comprises a switch, coupled to the gain boost circuit, wherein operating the switch will control whether the gain boost is to be applied to the audio signal.

Abstract: A vehicle voice interface system calibration method comprising electronically convolving voice command data with voice impulse response data, electronically convolving audio system output data with feedback impulse response data, and calibrating the vehicle voice interface system. The voice command data is electronically convolved with voice impulse response data representing a voice acoustic signal path between an artificial mouth simulator and a first microphone, to simulate a voice acoustic transfer function pertaining to the passenger compartment. The audio system output data is convolved with feedback impulse response data representing a feedback acoustic signal path between a vehicle audio system output and a second microphone, to simulate a feedback acoustic transfer function pertaining to the passenger compartment. The voice interface system is calibrated to recognize voice commands represented by the voice command data based on the simulated voice and feedback acoustic transfer functions.

Abstract: A processing circuit may implement an adaptive filter having a response that generates an anti-noise signal from a reference microphone signal, one or more filters for modeling an electro-acoustic path of the anti-noise signal from a location of an error microphone to an eardrum of a listener and having a response that generates a filtered reference microphone signal from the reference microphone signal, one or more filters for modeling an acoustic path of ambient audio sounds from the location of the error microphone to the eardrum and having a response that generates a synthesized playback corrected error signal based on the error microphone signal, wherein the synthesized playback corrected error signal is indicative of ambient audio sounds present at the eardrum, and a coefficient control block that shapes the response of the adaptive filter in conformity with the filtered reference microphone signal and the synthesized playback corrected error signal by adapting the response of the adaptive filter to min

Abstract: Embodiments of an article of manufacture, a system for processing audio signals and a computer-readable storage medium containing program instructions for processing audio signals are described. In one embodiment, an article of manufacture comprising at least one non-transitory, tangible machine readable storage medium containing executable machine instructions for processing audio signals, where execution of the executable machine instructions by a processing device causes the processing device to perform steps, which include estimating a spectral difference between a first audio signal and a second audio signal that carry the same audio content, transforming the second audio signal based on the spectral difference and generating an output audio signal based on the transformed second audio signal. Other embodiments are also described.

Abstract: A personal audio device, such as a headphone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal using one or more microphone signals that measure the ambient audio. The anti-noise signal is combined with source audio to provide an output for a speaker. The anti-noise signal causes cancellation of ambient audio sounds that appear in the microphone signals. A processing circuit uses the reference microphone to generate the anti-noise signal using one or more adaptive filters. The processing circuit also includes low-pass filters that remove quantization noise images at the output of the adaptive filter to reduce the dynamic range required at the output of the adaptive filter.

Abstract: A system and method is described for estimating residual echo and performing residual echo suppression on a signal. In particular, the system and method described herein: 1) provides a more accurate coherence-based approach where the sub-band nature of coherence-based residual echo estimation is leveraged using sub-band-based coherence measures and upper-bound envelopes to guide residual echo estimates; 2) provides joint estimation of the residual echo and a background stationary noise-floor; 3) provides more accurate residual echo estimation by combining the above two measures with information on near-end activity to selectively adjust the residual-echo estimation in sub-bands; and 4) provides improved control of near-end distortion by leveraging the noise-floor estimate and the internally calculated signal-to-echo ratios as additional guides/limits to help balance, flexibly, and as needed, near-end distortion with residual echo suppression.

Abstract: A system includes a stop-start module that determines, based on characteristics of a vehicle, whether to deactivate an engine of the vehicle, that selectively deactivates the engine based on the characteristics, that, subsequent to deactivating the engine, selectively reactivates the engine based on the characteristics, and that generates an indication signal corresponding to the determination. A driver alert module receives the indication signal and selectively generates, based on the indication signal, a masking sound to be played by an audio system of the vehicle while the engine is deactivated.

Abstract: A device is provided that includes a microphone, a surface, an accelerometer or transducer, and a processor. The surface may be substantially transparent and have a side that is exposed to an external environment. The accelerometer or transducer may be coupled to the side of the surface that is exposed to the external environment and it may be utilized to obtain at least one measurement of acceleration of the surface based on an acoustic vibration. The processor may receive the accelerometer's or transducer's measurement and an input from the microphone. The processor may generate an output based on the accelerometer or transducer measurement and microphone input.

Abstract: An acoustic noise cancellation (ANC) process is performed during in-the-field use of a personal listening audio device, using a control filter to produce anti-noise by the device. The process includes computing an S_hat filter that estimates a signal path between an earpiece speaker of the device and an error microphone that are at a user's ear. A response associated with the computed S_hat filter is compared to a predetermined response that is stored in the device. The control filter is adjusted in accordance with the comparison. Other embodiments are also described and claimed.

Abstract: The present invention relates to a personal headphone device, system and method configured to combine a headphone and earbud into one acoustical product. The headphone earbud device is configured with an adaptive connection for controlling the audio signals and/or device providing the audio signals. The adaptive connection includes an electro mechanical and/or mechanical connection so that when an earbud is placed into a headphone contact plates on the earbud mate with contact plates on the interior recess of the headphone so as to energize a loudspeaker in the headphone and or to control the device providing the audio signals.

Abstract: In accordance with methods and systems of the present disclosure, an integrated circuit for implementing at least a portion of a personal audio device may include an output including an anti-noise signal, a reference microphone input, an error microphone input, and a processing circuit. The processing circuit may implement an adaptive filter having a response that generates the anti-noise signal from the reference microphone signal to reduce the presence of the ambient audio sounds heard by the listener, wherein the processing circuit may implement a coefficient control block that shapes the response of the adaptive filter in conformity with the error microphone signal and the reference microphone signal by adapting the response of the adaptive filter in accordance with a calculated narrow-band-to-full-band ratio, wherein the narrow-band-to-full-band ratio is a function of a narrow-band power of the reference microphone signal divided by a full-band power of the reference microphone signal.

Abstract: The suppression device for outdoor noises in indoor space solves the technical problems on realizing better sound insulation effect within the room space and creating a quiet atmosphere for people's living environment. The structure includes an anti-noise sound source synchronized to and invert with outdoor noises. The circuit structure of suppression device includes a directional reception and processing circuit for outdoor noises, a attenuation control circuit, a multi-channel digital amplifier circuit, and loudspeaker being installed at the inlet of indoor noises. The directional reception and processing circuit for outdoor noises processes the noise signals collected from the outdoor environment and generates the inverted-phase signals, and then transmits them to the input terminal of attenuation control circuit.

Abstract: A personal audio device including earspeakers, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal for each earspeaker from at least one microphone signal that measures the ambient audio, and the anti-noise signals are combined with source audio to provide outputs for the earspeakers. The anti-noise signals cause cancellation of ambient audio sounds at the respective earspeakers. A processing circuit uses the microphone signal(s) to generate the anti-noise signals, which can be generated by adaptive filters. The processing circuit controls adaptation of the adaptive filters such that when the processing circuit detects that either of the earspeakers are off-ear, a gain applied to the anti-noise signals is reduced.

Abstract: A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Noise is injected either continuously and inaudibly below the source audio, or in response to detection that the source audio is low in amplitude, so that the adaptation of the secondary path estimating adaptive filter can be maintained, irrespective of the presence and amplitude of the source audio.

Abstract: A gain of a signal representing sounds detected by a talk-through and/or feedforward ANR microphone of a talk-through function provided by a communications headset is reduced in response to a user of the communications headset speaking.

Abstract: An adaptive control unit is described for receiving an analog input signal containing at least an indication of a parameter to be controlled to generate an analog output signal for control of the parameter. The analog input signal contains a fed back component resulting from the analog output signal. The adaptive control unit comprises an analog filter having an adjustable gain, a gain adjuster for adjusting the gain of the analog filter using a feedforward adjustment method, and a filter for compensating for the fed back component in the analog input signal.

Abstract: An improved user experience is provided for passengers of a transportation vessel, such as an airplane. A passenger's experience is enhanced by allowing the passenger to enjoy media provided by an entertainment device without ambient noise. When the passenger requests accesses to a media item through the entertainment device, a microphone in the entertainment system generates an ambient noise signal based on captured ambient noise. A noise cancellation device generates a predictive noise cancelling signal based on the ambient noise signal. To generate the predictive noise cancelling signal, the noise cancellation device inverts the ambient noise signal and applies a predictive phase shift to the signal based on an estimated distance between the microphone and the passenger's ears. The noise cancelling signal is mixed with audio of the media item.

Abstract: Embodiments are directed towards enabling headphones to perform active noise cancellation for a particular user. Each separate user may enable individualized noise canceling headphones for one or more noise environments. When the user is wearing the headphones in a quiet environment, a user may employ a computer to initiate determination of a plant model of each ear cup specific to the user. When the user is wearing the headphones in a target noise environment, the user may utilize the computer to initiate determination of operating parameters of a controller for each ear cup of the headphones. The computer may provide the operating parameters of each controller to the headphones. And the operation of each controller may be updated based on the determined operating parameters. The updated headphones may be utilized by the user to provide active noise cancellation.

Abstract: The present technology provides adaptive noise reduction of an acoustic signal using a sophisticated level of control to balance the tradeoff between speech loss distortion and noise reduction. The energy level of a noise component in a sub-band signal of the acoustic signal is reduced based on an estimated signal-to-noise ratio of the sub-band signal, and further on an estimated threshold level of speech distortion in the sub-band signal. In various embodiments, the energy level of the noise component in the sub-band signal may be reduced to no less than a residual noise target level. Such a target level may be defined as a level at which the noise component ceases to be perceptible.

Abstract: A noise suppression apparatus includes: a conversion unit to convert a recorded sound signal in a time domain into a spectrum in a frequency domain; a setting unit to set a suppression gain indicating a degree of suppression on each spectrum for each frequency spectrum on the basis of a nonstationarity-value variation in time of the respective spectrum; a suppression unit to suppress each of the spectrum on the basis of the suppression gain set by the setting unit for each frequency spectrum; and an inverse conversion unit to perform an inverse conversion to the conversion by the conversion unit on the spectrum having been subjected to the suppression processing by the suppression unit.

Abstract: Headphones with acoustically resistant ear cups, an external noise sensor mounted thereto that monitors ambient noise, and internal sensors to monitor noise within each ear cup are disclosed. A processing system monitors the external and interior sound detected by the sensors and compares the level inside the ear cups with the detected level of ambient noise. It activates a transducer such as a vibrator, buzzer, or light as needed to indicate when the level within the ear cups has exceeded the predetermined criteria thereby indicating improper fit of the headphones. Alternative embodiments include wirelessly communicating the collected data to an auxiliary computer for remote data collection, storage and monitoring. The headphones may also provide a sound dosimeter; bandpass filtering; automatic noise reduction with feed forward and/or feed back; wireless voice and data communication; and a voice activated switch, all using elements of the headphone fit detection circuitry.

Abstract: For generating privacy, a detection module detects an optical lingual cue from user speech that comprises an audible signal. A generation module transmits an inverse audible signal generated from the optical lingual cue.

Abstract: A noise signal is estimated based on a captured audio signal captured from a sound capture unit. It is determined whether the estimated noise signal thus estimated is in a noiseless state. If it is determined that the estimated noise signal is in the noiseless state, the captured audio signal is analyzed as a target sound signal, and a characteristic obtained by the analysis is learned and modeled, thereby generating a target sound model.

Abstract: There is provided a signal processing device s including a noise cancellation process clock generation unit configured to generate a noise cancellation process clock having a predetermined fixed frequency, a noise canceling unit configured to include a noise canceling filter operating based on the noise cancellation process clock and generating a noise canceling signal having a signal property of canceling an external noise component based on an input audio signal including the external noise component picked up by a microphone, and an addition unit superimposing the noise canceling signal generated by the filter on a digital audio signal, and a sampling rate conversion unit configured to rate-convert the input digital audio signal sampled at a clock in asynchrony with the noise cancellation process clock to a signal at a sampling frequency in synchrony with the noise cancellation process clock and to supply the rate-converted signal to the addition unit.

Abstract: A sound reproducing device includes: a plug section configured to receive input of L-channel and R-channel audio signals; an L-channel housing section including at least an L-channel driver unit configured to produce sound on the basis of the L-channel audio signal, an L-channel microphone configured to collect external sound, and an L-channel microcomputer configured to perform setting control on noise-canceling processing on the basis of a collected sound signal of the microphone; an R-channel housing section including a same corresponding configuration as those of the L-channel housing section; and an in-cord housing section formed so as to be inserted in a wiring cord for supplying the signals inputted from the plug section to the L-channel and the R-channel housing sections, wherein the in-cord housing section is provided with a communication terminal for allowing data communication between the L-channel microcomputer and the R-channel microcomputer, and an external apparatus.

Abstract: An active noise control system for exhaust systems of a combustion engine operated vehicle comprises an anti-sound control connectable to an engine control of the vehicle and a loudspeaker connected to the control for receiving control signals and designed for generating an anti-sound in a sound generator, fluidically connectable to the exhaust system. In the control, at least two curves are stored in order to cancel airborne sound conducted in the exhaust system through outputting the signal to the loudspeaker. The curves cover different temperature ranges of the exhaust gas, which temperature ranges overlap one another by pairs or directly adjoin one another. The control is furthermore designed to select a curve suitable for a respective temperature of the exhaust gas conducted in the exhaust system from the available curves by means of signals output by the engine control and output signals to the loudspeaker making use of this curve.

Abstract: Clock synchronization for an acoustic echo canceller (AEC) with a speaker and a microphone connected over a digital link may be provided. A clock difference may be estimated by analyzing the speaker signal and the microphone signal in the digital domain. The clock synchronization may be combined in both hardware and software. This synchronization may be performed in two stages, first with coarse synchronization in hardware, then fine synchronization in software with, for example, a re-sampler.

Abstract: A system and method for reproducing audio sound. Audio sound, based on an audio signal, is emitted within a space comprising an audio beamwidth. Modulated ultrasonic sound energy based on a modulated ultrasonic sound signal is emitted in an ultrasonic sound direction within an ultrasonic beamwidth that is less than and within the audio beamwidth. The modulated ultrasonic sound signal is generated such that the emitted modulated ultrasonic sound energy creates an audible cancellation sound with an amplitude substantially equal to an amplitude of the audio sound at a point within the ultrasonic beamwidth so as to combine with and cancel the audio sound at the point by being substantially out of phase with the audio sound along the ultrasonic sound direction.

Abstract: A method for controlling adaptation of a feedback suppression filter in a hearing aid comprises the step of suspending the adaptation of the feedback suppression filter when the level of a hearing aid reference signal is below a predetermined threshold. The invention further provides a hearing aid with a feedback suppression filter and with means for suspending adaptation of the feedback suppression filter.

Abstract: In an active noise reducing headphone, a signal processor is configured to apply first feedback filters to the feedback signal path, causing the feedback signal path to operate at a first gain level, as a function of frequency, during a first operating mode, and apply second feedback filters to the feedback signal path, causing the feedback signal path to operate at a second gain level less than the first gain level at some frequencies during a second operating mode. The first gain level is a level of gain that results in effective cancellation of sounds transmitted through or around the ear cup and through the user's head, and the second level is a level of gain that is matched to the level of sound of a typical wearer's voice transmitted through the wearer's head when wearing the headphone.

Abstract: A noise cancellation system generates a noise cancellation signal from a signal representing ambient noise by signal processing. The signal processing applies a controllable gain value, and includes a high pass filter with a controllable cut-off frequency. A control block detects a wind amplitude. The cut-off frequency of the high pass filter is controlled based on the detected wind amplitude. A low pass function is applied to the detected wind amplitude, and the controllable gain is adjusted based on the output of the low pass function.

Abstract: Electronic devices and accessories are provided that may communicate over wired communications paths. The electronic devices may be portable electronic devices such as cellular telephones or media players and may have audio connectors such as 3.5 mm audio jacks. The accessories may be headsets or other equipment having mating 3.5 mm audio plugs and speakers for playing audio. Microphones may be included in an accessory to gather voice signals and noise cancellation signals. Analog-to-digital converter circuitry in the accessory may digitize the microphone signals. Digital voice signals and voice noise cancellation signals can be transmitted over the communications path and processed by audio digital signal processor circuitry in an electronic device. Digital-to-analog converter circuitry in the accessory may convert digital audio signals to analog speaker signals.

Abstract: Two ear cups are coupled by a flexible member. Each ear cup includes a speaker mounted on an internal portion thereof and is configured to form an air pressure seal around an ear of a user when the apparatus is placed on the user. The flexible member couples the two ear cups and ijs configured such that, when the apparatus is placed on the user, each ear cup completely covers an associated ear of the user and forms an air pressure seal around the associated ear. A microphone is electrically coupled to the speaker in each ear cup for transmitting ambient sound to the user when the apparatus is placed on the user. An indicator light may be provided which is configured to turn on when the microphone is active. The microphone and/or the indicator light may be mounted on the flexible member or on one of the ear cups.

Abstract: An acoustic apparatus including circuitry to correct for acoustic cross-coupling of acoustic drivers mounted in a common acoustic enclosure. A plurality of acoustic drivers are mounted in the acoustic enclosure so that motion of each of the acoustic drivers causes motion in each of the other acoustic drivers. A canceller cancels the motion of each of the acoustic drivers caused by motion of each of the other acoustic drivers. A cancellation adjuster cancels the motion of each of the acoustic drivers that may result from the operation of the canceller.

Abstract: A method for reducing the noise emission of a transformer, the transformer tank of which is filled with liquid and the tank wall of which vibrates during operation, is provided. The method is characterized by the sequence of the following method steps: detecting natural frequency values of the tank wall for at least one excitation frequency; determining at least one eigenmode for which the vibration of the tank wall is composed at an excitation frequency, from the natural frequency values, wherein areas of large curvature are determined on the tank wall; arranging at least one vibration loading device in at least one of said areas; and controlling the at least one vibration loading device by means of a control device in order to counteract the vibration of the tank wall.

Abstract: An apparatus comprising: an input configured to receive at least three microphone audio signals, the at least three microphone audio signals comprising at least two near microphone audio signals generated by at least two near microphones located near to an desired audio source and at least one farmic audio signal generated by a farmic located further from the desired audio source; a first interference canceller module configured to generate a first processed audio signal based on a first selection from the near microphone audio signals; at least one further interference canceller module configured to generate at least one further processed audio signal based on at least one further selection from the at least three microphone audio signals; a comparator configured to determine from the first processed audio signal and the at least one further processed audio signal the audio signal with greater noise suppression.

Abstract: A system for controlling fan noise includes a fan, a sensor, a signal processing unit, a net structure, and a piezoelectric element. The fan has an airflow inlet and an airflow outlet. The sensor is disposed near the airflow outlet and is used for receiving a sound signal made by the fan. After the signal processing unit receives the sound signal sent by the sensor, the signal processing unit provides an inversed phase signal by analysis and computation. The net structure is disposed at the airflow inlet. The piezoelectric element is disposed on the net structure. When the piezoelectric element receives the inversed phase signal provided by the signal processing unit, the piezoelectric element vibrates the net structure, so that the net structure generates an inversed phase sound to offset a noise made by the fan.

Abstract: A personal audio device including earspeakers, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal for each earspeaker from at least one microphone signal that measures the ambient audio, and the anti-noise signals are combined with source audio to provide outputs for the earspeakers. The anti-noise signals cause cancellation of ambient audio sounds at the respective earspeakers. A processing circuit uses the microphone signal(s) to generate the anti-noise signals, which can be generated by adaptive filters. The processing circuit controls adaptation of the adaptive filters such that when an event requiring action on the adaptation of one of the adaptive filters is detected, action is taken on the other one of the adaptive filters. Another feature of the ANC system uses microphone signals provided at both of the earspeakers to perform processing on a voice microphone signal that receives speech of the user.

Abstract: A system is provided for enhancing a sound signal produced by an audio system in a listening environment by compensating for ambient noise in the listening environment. The system receives an electrical sound signal and generates a sound output therefrom. A total sound signal is sensed representative of the total sound level in the environment, where the total sound level includes the sound output and the ambient noise. The system extracts an ambient noise signal representative of the ambient noise from the total sound signal, using an adaptive filter with an adaptive step size, in response to the total sound signal and to a reference signal derived from the electrical sound signal. The system generates a control signal in response to the ambient noise signal and adjusts the sound output of the audio system to compensate for the ambient noise level in response to the control signal.

Abstract: Provided are methods and systems for noise suppression within multiple time-frequency points of spectral representations. A multi-feature cluster tracker is used to track signal and noise sources and to predict signal versus noise dominance at each time-frequency point. Multiple features, such as binaural and monaural features, may be used for these purposes. A Gaussian mixture model (GMM) is developed and, in some embodiments, dynamically updated for distinguishing signal from noise and performing mask-based noise reduction. Each frequency band may use a different GMM or share a GMM with other frequency bands. A GMM may be combined from two models, with one trained to model time-frequency points in which the target dominates and another trained to model time-frequency points in which the noise dominates. Dynamic updates of a GMM may be performed using an expectation-maximization algorithm in an unsupervised fashion.

Abstract: A multi-channel acoustic echo canceller arrangement comprises a microphone (111) providing a microphone signal having contributions from at least two audio sources (107, 109) to be cancelled. An echo canceling circuit (113, 115) performs echo cancellation of the two audio sources (107, 109) based on channel estimates for channels from each of the audio sources (107, 109) to the microphone (111). An estimation circuit (117) generates each of the channel estimates as a combination of a previous channel estimate and a channel estimate update where the combination includes applying a relative weight to the channel estimate update relative to the previous channel estimate. A weight processor 119 varies the relative weight in response to a time value. The arrangement may provide improved echo-cancellation for scenarios wherein the rendering of sound from the audio sources (107, 109) is time varying, such as when time varying decorrelation filters are used.

Abstract: A howling canceller applied to an acoustic system having a speaker and a microphone comprises: a filter insertion unit for inserting a notch filter at a frequency of an audio signal picked up by the microphone; a setting unit for setting the insertion time of the notch filter on the basis of the frequency at which the notch filter is inserted; and a releasing unit for, when the insertion time set by the setting unit has elapsed, releasing the notch filter, the insertion time of which has elapsed. The setting unit sets the insertion time of the notch filter to be shorter as the frequency at which the notch filter is inserted increases.