Abstract: Robust feedforward active noise cancellation is provided which can overcome or substantially alleviate problems associated with the diverse and dynamic nature of the surrounding acoustic environment. A multi-faceted analysis is performed to determine the direction (or directions) of propagation of noise in the surrounding acoustic environment. The direction of propagation is then utilized to determine direction-dependent characteristics of the acoustic path between a reference position where the noise is captured and a desired position where the noise is to be cancelled. These characteristics are used to form a feedforward signal adapted to cancel the noise at the desired position. By forming the feedforward signal based on direction-dependent characteristics of the acoustic path, the techniques described herein can achieve optimal noise cancellation at the desired location, regardless of the direction of propagation of the noise.

Abstract: Apparatus and method of an ANR circuit detecting instances of instability in at least the provision of feedback-based ANR, monitoring audio that includes feedback anti-noise sounds for acoustic output by an acoustic driver for a sound having characteristics indicative of instability including at least a frequency within a range of frequencies and an amplitude reaching at least a predetermined minimum amplitude, and perhaps also a sinusoidal waveform.

Abstract: A robust noise reduction system may concurrently reduce noise and echo components in an acoustic signal while limiting the level of speech distortion. The system may receive acoustic signals from two or more microphones in a close-talk, hand-held or other configuration. The received acoustic signals are transformed to frequency domain sub-band signals and echo and noise components may be subtracted from the sub-band signals. Features in the acoustic sub-band signals are identified and used to generate a multiplicative mask. The multiplicative mask is applied to the noise subtracted sub-band signals and the sub-band signals are reconstructed in the time domain.

Abstract: A signal processing apparatus includes a signal transforming unit transforming a first sound signal obtained by dividing a sound signal represented by a time function and by the predetermined time width into a second sound signal represented by a frequency function; a calculating unit determining a third sound signal which has a reduced influence of the operation sound by using the second sound signal and a sound signal representing the operation sound; a correcting unit performing a correction, by setting a sound signal representing the target sound as a reference signal, on the third sound signal based on the reference signal; and a signal inverse transforming unit inverse-transforming a sound signal on which the correction is performed from the sound signal represented by the frequency function into the sound signal represented by the time function.

Abstract: According to one embodiment, a sound signal compensation apparatus includes an input module, a compensation module, and an output module. The input module receives identification information identifying a first frequency with regard to a resonance of an ear closed by an earphone or headphone. The compensation module performs first compensation emphasizing a second frequency on a sound signal, the second frequency being determined based on the identification information or the first frequency. The output module outputs the compensated sound signal. The compensation module is configured to perform the first compensation emphasizing the second frequency, at which emphasis is greater than or equal to 2 dB and less than or equal to 12 dB.

Abstract: Apparatus and method of controlling provision of ANR, possibly of a personal ANR device, in which amplitudes of a piece of audio employed in the provision of ANR are monitored, and the compression of one or both of feedback and feedforward ANR reference sounds is made dependent on frequency such that a first sound of one frequency need only reach a lower amplitude to trigger compression, while a second sound of another frequency must reach a higher amplitude to trigger compression.

Abstract: A processing system generates an output signal which includes desired signal components, and reduces or eliminates tonal noise. The output signal may be provided to any subsequent signal processing system, including voice recognition systems, pitch detectors, and other processing systems. The subsequent processing systems are less likely to mistake tonal input signal noise for desired signal content, to needlessly consume computational resources to analyze noise, and to take spurious actions induced by the tonal noise.

Abstract: An audio signal compensation device includes: a signal processor configured to perform filtering on an input audio signal; a filter coefficients storage module configured to store a plurality of filter coefficients; a user interface configured to provide options for a determination of filter coefficients to a user and to obtain a selection result from the user; and a filter coefficients determining module configured to determine a set of filter coefficients among the plurality of filter coefficients based on the selection result.

Abstract: Apparatus and method of reducing the provision of ANR at an one end of a range of frequencies at which the ANR is provided without reducing the provision of the ANR at the other end of the range of frequencies by repeatedly reconfiguring coefficients of one or more digital filters to reduce the provision of ANR at the one end in increments at a first recurring interval, and then later reversing the reduction in the provision of the ANR at the one end by repeatedly reconfiguring coefficients of the one or more digital filters in increments at a second recurring interval.

Abstract: Disclosed herein is a digital filter circuit for producing a noise reduction signal for reducing noise based on a noise signal outputted from a microphone which collects the noise, including: an analog/digital conversion section; a first digital filter section; an arithmetic operation processing section; a second digital filter section; and a digital/analog conversion section. The first digital filter section and/or the second digital filter section are configured such that a predetermined attenuation amount is obtained within a predetermined range in the proximity of a sampling frequency around the sampling frequency.

Abstract: The present invention discloses a circuit with three-stage of power-on sequence used for suppressing the pop noise in audio system. It mainly comprises a first resistor (R1); a capacitor (Cout); a first switch (SW1); a second switch (SW2); a soft start device; a first feedback amplifier; and a second feedback amplifier. By using the three-stage of power-on sequence, the present invention can effectively suppress the pop noise when the audio driver is power on.

Abstract: A noise control device eliminates a possibility that a noise arriving at a control point is increased as compared to a case where noise control is not performed and has a reduced circuit scale. The device includes a controlling noise detector for detecting a given noise to output a controlling noise signal, a controlling filter section for signal-processing the controlling noise signal, by using a preset fixed filter coefficient, to output a control signal, and a control speaker for reducing the given noise, by emitting toward the control point a control sound based on the control signal. The device also includes a noise determination section for determining whether the given noise is a noise corresponding to the fixed filter coefficient, and an output control section for stopping output of the control signal from the controlling filter section when the given noise does not correspond.

Abstract: A clipping detection device calculates an amplitude distribution of an input signal for each predetermined period, calculates a deflection degree of the distribution on the basis of the calculated amplitude distribution, and then detects clipping of a communication signal on the basis of the calculated deflection degree of the distribution.

Abstract: A talk-through system for hearing protectors such as headphones, helmets, earplugs and the like, in which separate left and right microphones are controlled by separate left and right switches. The microphones allow ambient sound to be heard by the wearer of the hearing protector, and normally the wearer hears audio from both microphones in the appropriate ears. Pushing a switch causes the audio from the ear on which the switch is mounted to be enhanced and, preferably, switched to both ears. Various arrangements of control logic are provided such that activation of a switch can cause changes in audio processing.

Abstract: In an ANR circuit of a personal ANR device, a digital filter is structured to introduce one or more zeros to add gain to introduce positive phase in the provision of feedback-based ANR, wherein the gain follows a frequency-dependent “ski-slope” gain curve with little gain added at lower audible frequencies, with increasing gain that increases with frequency added at higher audible frequencies, and with the increasing gain flattening at frequencies above audible frequencies.

Abstract: An echo suppressing system includes: a sound output device for outputting sound based on a sound signal, including a passing section for allowing passage of a component of a different frequency band, and a plurality of sound output sections, each of which outputs sound based on each of the plurality of sound signals passed through the passing section; a summer for summing the plurality of sound signals to generate a reference sound signal; a sound input device for converting input sound into a sound signal; and an echo suppressor for suppressing echo based on the sound output by the sound output device, including an input section to which a sound signal is input from the sound input device as an observation sound signal, and a correction section for correcting the observation sound signal so as to suppress echo included in the observation sound signal.

Abstract: An apparatus, method and computer program, the apparatus including a loudspeaker configured to convert an electrical input signal into an acoustic output signal; a connecting portion configured to interchangeably connect to either a first adapter or a second adapter where the first adapter is configured to fit in a user's ear canal and the second adapter is configured to fit to a user's concha; and a regulator for regulating sound pressure level created by the acoustic output signal at an ear drum of the user in dependence on whether the first adapter or the second adapter is connected to the connecting portion.

Abstract: An active noise control system generates an anti-noise signal to drive a speaker to produce sound waves to destructively interfere with an undesired sound in a targeted space. The speaker is also driven to produce sound waves representative of a desired audio signal. Sound waves are detected in the target space and a representative signal is generated. The representative signal is combined with an audio compensation signal to remove a signal component representative of the sound waves based on the desired audio signal and generate an error signal. The active noise control adjusts the anti-noise signal based on the error signal. The active noise control system converts the sample rates of an input signal representative of the undesired sound, the desired audio signal, and the error signal. The active noise control system converts the sample rate of the anti-noise signal.

Abstract: A noise enhancement system for an automobile utilizes a single input of engine speed to derive a control signal used to drive a speaker. The speaker generates sounds that enhance or replicate the desired sounds from the engine. The output from the speaker is crafted dependent on the vehicle operating conditions. Instead of multiple transducers and inputs the noise enhancement system of this invention utilizes the single input of engine RPM engine speed. By utilizing only engine speed, the noise enhancement system is cost effective and significantly less complex.

Abstract: An active noise control system generates an anti-noise signal to drive a speaker to produce sound waves to destructively interfere with an undesired sound in a targeted space. The speaker is also driven to produce sound waves representative of a desired audio signal. Sound waves are detected in the target space and a representative signal is generated. The representative signal is combined with an audio compensation signal to remove a signal component representative of the sound waves based on the desired audio signal and generate an error signal. The active noise control adjusts the anti-noise signal based on the error signal. The active noise control system converts the sample rates of an input signal representative of the undesired sound, the desired audio signal, and the error signal. The active noise control system converts the sample rate of the anti-noise signal.

Abstract: The subject matter of this specification can be embodied in, among other things, a computer-implemented method for removing noise from audio that includes building a sound model that represents noises which result from activations of input controls of a computer device. The method further includes receiving an audio signal produced from a microphone substantially near the computer device. The method further includes identifying, without using the microphone, an activation of at least one input control from among the input controls. The method further includes associating a portion of the audio signal as corresponding to the identified activation. The method further includes applying, from the audio model, a representation of a noise for the identified activation to the associated portion of the audio signal so as to cancel at least part of the noise from the audio signal.

Abstract: An apparatus configured as a compandor to achieve a defined dynamic range for an output signal in response to an input signal. In particular, the apparatus comprises a first circuit adapted to generate a first signal from the input signal, wherein the first signal includes a first dynamic range (e.g., a first sensitivity and first compression point); and a second circuit adapted to generate a second signal from the input signal, wherein the second signal includes a second dynamic range (e.g., a second sensitivity and second compression point) that is different from the first dynamic range of the first signal. The apparatus may further include a third circuit adapted to generate an output signal related to a sum of the first and second signals. By adjusting the first and second dynamic ranges, an overall dynamic range for the output signal of the companding apparatus may be achieved.

Abstract: A noise control device includes a signal processor that detects a noise outputted from a noise source, and generates a control signal based on the noise and a control acoustic system that generates a control sound for canceling the noise, based on the control signal outputted from the signal processor. The noise control device also includes an output correction section that corrects the control signal outputted from the signal processor, in a frequency band for which a noise control process time ?, which is a time period from when the noise is outputted from the noise source to pass through the signal processor and the control acoustic system to when the control sound reaches the control point, is larger than a noise transfer time T, which is a time period from when the noise is outputted from the noise source to when the noise reaches the control point via the noise transfer system (?>T).

Abstract: A conversation shielding system comprises sensors that detect the location of a confidential conversation and the presence and location of a potential eavesdropper, audio output devices that produce masking sounds to shield the conversation from the eavesdropper, and a controller that automatically controls the operation of the output devices in response to data from the sensors. An optional portable controller may manually engage the system. A method for shielding conversation comprises identifying a conversation to be shielded, detecting a potential eavesdropper, automatically determining masking sound types, locations and volume that will shield the conversation, directing emission of masking sounds from at least one audio output device in order to shield the conversation, including adjusting the masking sound type, location, and volume in response to movement of the conversation or the eavesdropper, and continuing to shield the conversation until it ends or the eavesdropper is no longer detected.

Abstract: A region of air is manipulated to reflect, absorb, or redirect sound energy to prevent the sound energy from reaching a listener separated from the sound source by the region of air. The region of air may be manipulated by directing ultrasonic sound waves with a sound pressure level of at least 140 decibels at the region of air.

Abstract: In an echo processing method and device which can detect an accurate echo section without effects of a far end signal, an echo delay, and a reduction of an echo cancellation amount, a signal of a specified frequency band is generated in conformity with a near end signal, and the signal of the specified frequency band is added to the near end signal to form a transmitting signal. Receiving signals are separated into the signal of the specified frequency band and a signal of a band other than the specified frequency band. An echo section is detected based on the signal of the specified frequency band separated. An echo component in the signal of the band other than the specified frequency band is removed and a level of the echo component is detected based on the near end signal in the echo section.

Abstract: A noise reduction system for actively blocking a noise source for a means of transport. The noise reduction system comprises at least one counter sound source and at least one intensity sensor. The at least one counter sound source and the at least one intensity sensor are arranged in a measuring region. In the measuring region, measuring of the noise intensity of the noise source and measuring of the counter sound intensity of the counter sound source are by the intensity sensor. Based on the measured noise intensity and the counter sound intensity, the counter sound source is controllable such that the sound energy input of the noise source can be globally reduced by the counter sound source.

Abstract: Health-sensing and health-action devices and systems are generally described. The health-sensing device may include one or more of a sensor, a filter, and a transmitter. The sensor may be configured to sense one or more factors relating to an indicator of a health related condition or occurrence such as snoring and may include one or more microphone devices, accelerometers, and/or MEMs devices. The filter may be configured to evaluate a signal from the sensor and determine if the indicator has been detected. The transmitter may be arranged for initiating a transmission based on a signal from the filter. The health-action device may be configured for responding to an indicator of a health related condition or occurrence of a user and may include one or more of a receiver, a processor, and a responder. The health-action device may stimulate the user or may cancel the snoring sound.

Abstract: An active silencer includes: a speaker generating control sound which interferes with noise; a microphone detecting noise remaining after the interference as a remaining noise signal; a sound quality evaluation unit evaluating the sound quality of the remaining noise and output a result of the sound quality evaluation; an actuation signal determination unit determining, according to the result of the sound quality evaluation, the detection timing of the frequency component of the remaining noise signal to be used when the control sound is generated for a plurality of bands of the remaining noise, corresponding to the plurality of bands of a reference signal corresponding to the noise; and a control signal generation unit generating and output a control signal for generation of the control sound depending on a plurality of bands of the determined remaining noise signal and a plurality of bands of the reference signal corresponding to the noise.

Abstract: A multichannel echo canceller according to the present invention includes an echo cancellation section which receives loudspeaker input signals sp1, sp2 including a second acoustic signal to be respectively inputted to a plurality of loudspeakers 10, 20 provided in a first location and detection signals m1, m2 detected by a plurality of microphones 11, 21 provided in the first location; separates a first acoustic signal and a second acoustic signal, which are included in the detection signals m1, m2, by performing signal processing based on an independent component analysis; cancels as an echo the second acoustic signal, which is included in the detection signals m1, m2, by outputting only the separated first acoustic signal to a plurality of loudspeakers 30, 40 provided in a second location.

Abstract: A system and method facilitating signal enhancement utilizing an adaptive filter is provided. The invention includes an adaptive filter that filters an input based upon a plurality of adaptive coefficients, the adaptive filter modifying at least one of the adaptive coefficients based on a feedback output. The invention further includes a feedback component that provides the feedback output based, at least in part, upon a non-linear function of the acoustic reverberation reduced output. The invention further provides a noise statistics component that stores noise statistics associated with a noise portion of an input signal and a signal+noise statistics component that stores signal+noise statistics associated with a signal and noise portion of the input signal.

Abstract: Apparatus and Method for canceling or reducing voice sounds produced during a conversation by the user of a cellular telephone or other communication device such that other persons close to the user cannot hear the users voice and is not disturbed by the conversation.

Abstract: The systems and methods described herein may filter and eliminate noise from natural language utterances to improve accuracy associated with speech recognition and parsing capabilities. In particular, the systems and methods described herein may use a microphone array to provide directional signal capture, noise elimination, and cross-talk reduction associated with an input speech signal. Furthermore, a filter arranged between the microphone array and a speech coder may use band shaping, notch filtering, and adaptive echo cancellation to optimize a signal-to-noise ratio associated with the speech signal. The speech signal may then be sent to the speech coder, which may use adaptive lossy audio compression to optimize bandwidth requirements associated with transmitting the speech signal to a main unit that provides the speech recognition, parsing, and other natural language processing capabilities.

Abstract: An active noise control system generates an anti-noise signal to drive a speaker to produce sound waves to destructively interfere with an undesired sound in a targeted space. The speaker is also driven to produce sound waves representative of a desired audio signal. Sound waves are detected in the target space and a representative signal is generated. The representative signal is combined with an audio compensation signal to remove a signal component representative of the sound waves based on the desired audio signal and generate an error signal. The active noise control adjusts the anti-noise signal based on the error signal. The active noise control system converts the sample rates of an input signal representative of the undesired sound, the desired audio signal, and the error signal. The active noise control system converts the sample rate of the anti-noise signal.

Abstract: A performance venue with a main speaker system is provided having a target coverage area within the performance venue. A performance area is located within the performance venue outside the target coverage area of the main speaker system. A low frequency directed audio source is positioned with respect to the performance area for active cancellation of low frequency sound spilling over into the performance area from the main speaker system. Control of the low frequency directed audio source is effected by an audio sensor is located in the performance area for generating an output correlated with low frequency spill over into the performance area.

Abstract: In a communication machine room wideband noise suppression system, a sensing unit detects a noise source produced by a fan during the operation thereof and generates a noise input signal and a feedback signal, which are sent to a signal amplifying unit for signal amplification. The amplified signals are then sent to a signal converting unit and converted into digital signals. A multi-channel hybrid controller receives the digital signals and makes corrections and conduct rapid convergence algorithm to derive a reverse digital signal, which is sent to the signal converting unit and converted into a reverse analog signal. The reverse analog signal is sent to the signal amplifying unit for power amplification to generate a control signal for driving a loudspeaker unit to produce interfering acoustic wave, so as to cancel out the noise source and achieve the purpose of eliminating wideband noise.

Abstract: A noise extraction method in which an environmental input which includes a noise indicia is selectively modified in accordance with an algorithm that includes one or more factors representing time response, amplitude of response, and error correction. The algorithm may also include thresholding, delay or convergence, among other techniques.

Abstract: The invention relates to an active noise cancellation device. The invention proposes a device and a method used to cancel the noise in an exhaust gas channel of a vehicle A noise signal is received form the exhaust gas channel, using a sound sensor, a frequency signal which has same amplitude as of noise signal but opposite phase, is generated, the generated frequency signal is acoustically mixed with the noise signal in the exhaust gas channel, using a sound converter, there by reducing the noise in the exhaust gas channel. The device also takes into account the reflection of the sound caused by an obstacle near the exhaust gas channel. A distance measuring device which is external to the active noise cancellation device provides the information about the distance between the obstacle and the exhaust gas channel. Based on the distance, the frequency signal is suitably modified to reduce the effect of sound reflections caused by the obstacle.

Abstract: A sound altering apparatus for altering predetermined sound levels of a sound producing device, the sound altering apparatus includes at least one piezoelectric foil sensor disposed relative to the sound producing device with the at least one piezoelectric foil sensor being operable to convert such sound wave energy into an electric sound signal one or more electric circuits in electrical communication with the at least one piezoelectric foil sensor for receiving the electric sound signal and shunting the electric sound signal to a ground connection, or to produce cancelling sound wave energy in the vicinity of the sound producing device, thereby reducing sound heard outside the sound producing device.

Abstract: A signal processing circuit is intended for use in a noise reduction system, which produces a target filter characteristic that would achieve optimal noise cancellation, the target filter characteristic including a resonant peak at a first frequency. The signal processing circuit comprises an analogue filter, which has an amplitude response that has a peak or trough at a center frequency, and has a phase response that switches polarity at the center frequency and tends to zero with increase or reduction in frequency away from the center frequency. The center frequency in the amplitude response is substantially equal to the first frequency. The analogue filter may be in the form of a series inductive-capacitive-resistive circuit, where the inductive component is in the form of a gyrator.

Abstract: An active noise reducing device includes switchover frequency memory which stores a speaker having weaker influence of level drop or dips in gain characteristics of transmission from first speaker and second speaker both working as secondary noise generators to microphone working as a residual signal detector, and also stores a frequency band of that speaker. Output switcher appropriately and selectively switches first speaker over to second speaker in response to the noise frequency at present calculated based on the rpm of engine by frequency calculator. This structure allows the active noise reducing device to work steadily even if level drop or a dip occurs in the gain characteristics of transmission from the speaker to the microphone, and allows suppressing the occurrence of abnormal sound due to divergence or distorted sound due to excessive output. Ideal noise reduction effect can be expected.

Abstract: A noise and vibration reduction system for an engine affixed to a body and a method for reducing vibrations in the body produced by that engine during operation. The present invention is particularly related to noise and vibration reduction in auxiliary power units installed on long-haul trucks and similar types of transportation vehicles. The primary noise and vibration reduction components of the present invention include an air intake silencer, a vibration tuner, and an engine speed limiter.

Abstract: Described herein is a system and method of emulating characteristics of an output signal of a first analog-to-digital converter by a second analog-to-digital converter employing signal processing. A signal processing module may receive a digital signal from the first analog-to-digital converter and alter the digital signal to define an altered digital signal such that the altered digital signal emulates a second digital signal that is characteristic of the second analog-to-digital converter, the second analog-to-digital converter differing from the first analog-to-digital converter.

Abstract: Gain characteristics depending on the frequency of a reference signal from speakers to a passenger position in a motor vehicle, i.e., gain characteristics which are an inversion of vehicle cabin sound field characteristics, are set in a first acoustic corrector. At the passenger position, a gain characteristic curve that is flat at various frequencies is achieved to prevent gain peaks and dips from occurring at the passenger position. A sound effect generated at the passenger position is made linear depending on the state of a noise source, or more specifically, a noise source caused by an accelerating action on the motor vehicle.

Abstract: Disclosed are a method and a device for suppressing vibrations (18) in an installation comprising an actuator (14) for actuating a flap (12) or a valve (70) used for metering a gas or liquid volume flow (16), especially in the area of HVAC, fire protection, or smoke protection. Vibrations (18) of the flap (12) or valve (70) caused by an unfavorable or wrong adjustment or configuration of the controller and/or by disruptive influences are detected and dampened or suppressed by means of an algorithm (1) that is stored in a microprocessor (49). Said algorithm is preferably based on the components recognition of vibrations (46), adaptive filtering (48), and recognition of sudden load variations (50).

Abstract: A method of measuring the degree of enhancement made to a voice signal by receiving the voice signal, identifying formant regions in the voice signal, computing stationarity for each identified formant region, enhancing the voice signal, identifying formant regions in the enhanced voice signal that correspond to those identified in the received voice signal, computing stationarity for each formant region identified in the enhanced voice signal, comparing corresponding stationarity results for the received and enhanced voice signals, and calculating at least one user-definable statistic of the comparison results as the degree of enhancement made to the received voice signal.

Abstract: An active noise control system prevents a continuous muffled sound from being generated as an abnormal sound under a high sound pressure from a speaker when a microphone as a sound detector is covered, and reduces noise immediately when the microphone is uncovered. A first threshold value as an upper limit value and a second threshold value as a lower limit value are provided for the filter coefficient of an adaptive notch filter. When the filter coefficient is greater than the first threshold value, a control sound is faded out according to a forgetting process. When the filter coefficient is smaller than the second threshold value, an adaptive control process is resumed. Even if the microphone is covered, the filter coefficient does not exceed the first threshold value as the upper limit value.

Abstract: While a vehicle incorporating an active vibration noise control apparatus is decelerating, hysteresis is given if an operating point moves from an operating point on a sampling period characteristic curve to an operating point on another sampling period characteristic curve. Even if a base period detected depending on noise contains fluctuations, a smooth noise control process is performed. Since a division number produced when the base period is divided by a sampling period is a real number, the freedom of design is widened. Less strict limits are posed on the processing capability of a CPU of the active vibration noise control apparatus to provide a wider control range.

Abstract: A system and method facilitating acoustic echo cancellation convergence detection is provided. The invention includes an acoustic echo cancellation convergence detector having a center clipping component, a convergence calculator, a convergence filter and a convergence statistic component. The invention provides for the acoustic echo cancellation convergence detector to provide an output regarding convergence of an adaptive filter based, at least in part, upon a filtered convergence statistic. Optionally, the acoustic echo cancellation convergence detector can provide an output associated with convergence history.

Abstract: Reduction of noise in a device having a console with one or more microphones and a source of narrow band distributed noise located on the console is disclosed. A microphone signal containing a broad band distributed desired sound and narrow band distributed noise is divided amongst a plurality of frequency bins. For each frequency bin, it is determined whether a portion of the signal within the frequency bin belongs to a narrow band distribution characteristic of the source of narrow band noise located on the console. Any frequency bins containing portions of the signal belonging to the narrow band distribution are filtered to reduce the narrow band noise.