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: An ANR circuit, possibly of a personal ANR device, reduces the degree of feedforward-based ANR that it provides in response to receiving an indication of the operation of a manually-operable control. The reduction of degree of feedforward-based ANR may be effected by turning off or otherwise deactivating the provision of feedforward-based ANR, reducing a range of frequencies of environmental noise sounds attenuated by the feedforward-based ANR to provide less attenuation of sounds detected by a feedforward microphone that are in a range of frequencies deemed to be those of human speech, and/or creating a notch in the range of frequencies of environmental noise sounds attenuated by the feedforward-based ANR to provide less attenuation of sounds detected by the feedforward microphone that are in a range of frequencies deemed to be those of human speech.

Abstract: An active noise control system includes a filter coefficient updating unit including an imaginary term estimator. The imaginary term estimator estimates an imaginary term Ie from a real term Re of an error signal e supplied from a microphone. The filter coefficient updating unit updates a filter coefficient W of an adaptive filter based on the imaginary term Ie, the real term Re, and a corrective signal supplied from a reference signal corrector. The filter coefficient updating unit updates the filter coefficient W successively in respective sampling periods.

Abstract: Disclosed is an acoustic device comprising an enclosed housing defining an inner volume and having a front and a back; an acoustic port penetrating the front of the enclosed housing; a first and second sense structure attached to the inside of the housing and defining a gap between the first and second sense structures; a front volume defined by the portion of the inner volume between the first sense structure and the front of the housing; a back volume defined by the portion of the inner volume between the second sense structure and the back of the housing; and at least one vent in the first sense structure operatively connecting the front volume and the gap, wherein the acoustic device has a cutoff frequency above approximately 100 Hz.

Abstract: A noise canceling system comprises a microphone (103) for generating a captured signal representing sound in an audio environment and a sound transducer (101) for radiating a sound canceling audio signal in the audio environment. A feed-back path (105, 107, 109, 111, 113) exists from the microphone (103) to the sound transducer (101) and comprises a feedback filter (109). A tone processor (119) determines a tone component characteristic for a tone component of a feedback signal of the feedback path (105, 107, 109, 111, 113) and an adaptation processor (121) adapts the feedback path in response to the tone component characteristic. The invention allows detection of the onset of instability and dynamic compensation to mitigate or prevent such instability. Accordingly increased design freedom for the feedback filter is achieved resulting in improved noise cancellation.

Abstract: An acoustic transducer device is provided. The device includes a body, a speaker, a microphone, and a processor. The body has a cavity, a sound exit, and a sound entrance. The cavity interflows with the sound exit and accommodates the speaker. The microphone is disposed within the body beside the speaker. The microphone interflows selectively with the cavity or the sound entrance. The processor is electrically connected to the speaker and the microphone. When the microphone interflows with the cavity, the microphone receives a sound signal generated from the cavity and transmits the sound signal to the processor for cancelling noise in the cavity. When the microphone interflows with the sound exit, the microphone receives an external sound signal and transmits the external sound signal to the processor for cancelling noise from the external.

Abstract: A subtractor subtracts a first control signal output from a first bandpass filter from an error signal, and supplies a differential signal to a second bandpass filter. The second bandpass filter, which has a central frequency of 70 Hz, is affected by an operation of the first bandpass filter, i.e., a first control signal, which has a central frequency of 40 Hz. The first bandpass filter is not affected by an operation of the second bandpass filter, i.e., the second control signal.

Abstract: A noise canceling system comprises a microphone (103) generating a captured signal and a sound transducer (101) radiating a sound canceling audio signal in the audio environment. A feedback path (109) from the microphone (103) to the sound transducer (101) comprises a non-adaptive canceling filter (115) and a variable gain (117) and receives the captured signal and generates a drive signal for the sound transducer (101). A gain detector determines a secondary path gain for at least part of a secondary path of a feedback loop. The secondary path may include the microphone (103), the sound transducer (101), and the acoustic path therebetween but does not include the non-adaptive canceling filter (115) or the variable gain (117). A gain controller (121) adjusts the gain of the variable gain (117) in response to the secondary path gain. The system uses simple gain estimation and control to efficiently compensate for variations in the secondary path to provide improved stability and noise canceling performance.

Abstract: A system includes a noise detector configured to identify undesirable noise components in an acoustic signal and a noise energy profiler configured to analyze the identified undesirable noise components and generate a noise energy profile. In the system, a cancelation profile generator is configured to generate a noise cancelation profile based at least in part on information in the noise energy profile, and a cancelation profile effector is configured to translate the noise cancelation profile into values for a programmable circuit.

Abstract: Acoustic noise suppression is provided in multiple-microphone systems using Voice Activity Detectors (VAD). A host system receives acoustic signals via multiple microphones. The system also receives information on the vibration of human tissue associated with human voicing activity via the VAD. In response, the system generates a transfer function representative of the received acoustic signals upon determining that voicing information is absent from the received acoustic signals during at least one specified period of time. The system removes noise from the received acoustic signals using the transfer function, thereby producing a denoised acoustic data stream.

Abstract: A variable-bandwidth adaptive notch filter which cancels howling from an input signal with a bandwidth varying according to a howling frequency to generate an output signal.

Abstract: A person-support apparatus comprises a frame, a sound generating device, a user interface, and a controller. The sound generating device is configured to generate an audible sound. The user interface is configured to receive an input from a user. The input corresponds to at least one of a sound conditioning system mode and an audible sound adjustment. The controller is electrically coupled to the sound generating device and the user interface. The controller is configured to control the operation of the sound generating device in accordance with the input from the user interface.

Abstract: A noise cancellation system for an audio system such as a mobile phone handset, or a wireless phone headset has a first input for receiving a first audio signal from one or more microphone positioned to receive ambient noise, and a second input for receiving a second audio signal from a microphone positioned to detect the user?s speech, as well as a third input for receiving a third audio signal for example representing the speech of a person to whom the user is talking. A first noise cancellation block receives the first audio signal and generates a first noise cancellation signal, and this is combined with the third audio signal to form a first audio output signal. A second noise cancellation block receives at least a part of the first audio signal and said second audio signal and applying noise cancellation to generate a second audio output signal.

Abstract: This document discusses, among other things, systems and methods for active noise cancellation. One example system includes a digital ANC circuit configured to receive first audio information from a first microphone and to produce an a digital anti-noise signal configured to attenuate noise sensed by the first microphone; an analog ANC circuit configured to receive second audio information from a second microphone and to produce an analog anti-noise signal configured to attenuate noise sensed by the second microphone; and wherein the system is configured to receive an intended audio signal and to provide an output signal for a speaker using the intended audio signal, the analog anti-noise signal, and the digital anti-noise signal.

Abstract: In an active muffler having improved response characteristics, a speaker section includes a diaphragm adapted to generate sound, a voice coil for driving the diaphragm, and a distance sensor to detect the movement of the diaphragm. A light generated by the LED is reflected by the diaphragm, the reflected light is detected by a phototransistor to thereby measure the distance to the diaphragm, so that the movement of the diaphragm is detected. Noise is detected by a microphone, and a signal having opposite phase to that of the noise is generated by an opposite-phase generating section. The difference between the opposite-phase signal and the signal of the distance to the speaker from the distance sensor is calculated and inputted to a PID control section. Such a difference indicates the delay of the speaker movement. Feedback control is performed in a direction in which the difference is canceled out.

Abstract: A method of active noise reduction is described which comprises receiving an audio signal (132) to be played, receiving a noise signal (105, 107, 116, 118, 126), indicative of ambient noise (111), from at least one microphone (104, 106), and generating a noise cancellation signal (114) depending on both, said audio signal (132) and said noise signal (105, 107, 116, 118, 126).

Abstract: A cosine wave over one period is stored as waveform data in a memory, and address shift values based on a phase lag in transfer characteristics from a speaker to a microphone are stored in a memory. An address shift value is read from the memory by referring to the frequency, and waveform data are read from the memory at addresses that are produced by shifting the addresses from which the reference cosine wave signal and the reference sine wave signal are read, by the address shift value. The read waveform data are used as a first reference signal and a second reference signal, which are applied to adaptive notch filters, to suppress vibratory noise.

Abstract: An adaptive active noise cancellation apparatus performs a filtering operation in a first digital domain and performs adaptation of the filtering operation in a second digital domain.

Abstract: An active noise cancellation (ANC) earphone for coupling to a host having a first jack and a second jack includes a sound source module, a sensing source module, a first connection module, and a second connection module. The sound source module is used for playing an audio signal. The sensing source module is coupled to the sound source module for sensing a noise near the sound source module. The first connection module has one end coupled to the sound source module and the other end inserted in the first jack, for transferring the audio signal generated by the host to the sound source module. The second connection module has one end coupled to the sensing source module and the other end inserted in the second jack, for transferring the noise sensed by the sensing source module to the host to generate a suppression signal for cancelling the noise.

Abstract: A system for sound cancellation includes a source microphone for detecting sound and a speaker for broadcasting a canceling sound with respect to a cancellation location. A computational module is in communication with the source microphone and the speaker. The computational module is configured to receive a signal from the source microphone, identify a cancellation signal using a predetermined adaptive filtering function responsive to acoustics of the cancellation location, and transmit a cancellation signal to the speaker.

Abstract: An ANR circuit, possibly of a personal ANR device, incorporates an signal processing topology to support the provision of feedback-based ANR, feedforward-based ANR and pass-through audio in which the topology incorporates a branch in which feedback anti-noise sounds are generated from feedback reference sounds received from a feedback microphone, a branch in which feedforward anti-noise sounds are generated from feedforward reference sounds, and a branch in which modified pass-through audio sounds are generated from pass-through audio sounds received from an audio source, wherein these three branches are combined to combine the generated sounds of each branch into a single output by which an acoustic driver, possibly of the personal ANR device, is driven.

Abstract: An ANR circuit, possibly of a personal ANR device, monitors a sound level of environmental sounds detected by a microphone external to an earpiece in which the ANR circuit is providing feedback-based ANR, and increases or decreases the degree of feedback-based ANR provided in response to the external microphone detecting a higher or lower sound level, respectively. Increasing and decreasing the degree of feedback-based ANR provided may be carried out by changing a variable loop gain of the ANR circuit and/or a range of frequencies of environmental sounds attenuated by the feedback-based ANR.

Abstract: In a personal ANR device having a pair of earpieces, each having a feedforward microphone and an ANR circuit associated therewith, each ANR circuit provides digital data representing environmental noise sounds detected by each ANR circuit's associated feedforward microphone. Such digital data may represent the environmental noise sounds as detected with little or not modification, or such digital data may be modified to some degree within each ANR circuit, perhaps to limit the range of frequencies that such digital data represents, before being provided to the other ANR circuit.

Abstract: An ANR circuit, possibly of a personal ANR device, reduces the degree of feedforward-based ANR that it provides in response to receiving an indication of the operation of a manually-operable control. The reduction of degree of feedforward-based ANR may be effected by turning off or otherwise deactivating the provision of feedforward-based ANR, reducing a range of frequencies of environmental noise sounds attenuated by the feedforward-based ANR to provide less attenuation of sounds detected by a feedforward microphone that are in a range of frequencies deemed to be those of human speech, and/or creating a notch in the range of frequencies of environmental noise sounds attenuated by the feedforward-based ANR to provide less attenuation of sounds detected by the feedforward microphone that are in a range of frequencies deemed to be those of human speech.

Abstract: A method of comparison between pieces of information characterizing reference values and pieces of information characterizing current values of sound-reproducing systems of a system of (n) microphones mi and (p) speakers hpj for the control of said sound-reproducing systems characterized in that: A: for each speaker hpj, at least one sound signal S is sent on the speaker hpj, for each microphone mi, a piece of information hpjmi is retrieved, this piece of information characterizing the sound-reproducing system comprising the speaker hpj and the microphone mi, B: a reference matrix Qr is saved, this reference matrix being constituted by all the pieces of reference information hpjmi obtained following the sending of the sound signal S, C: as soon as a comparison is to be made, the step A is run with a sound signal S? to obtain current information on a matrix Q, D: the matrices Q and Qr are compared.

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: Soundproofing a rack by installing at least one duct on at least one panel of the rack, or as part of the side panels of the rack, or is mounted inside the rack as a drawer in such a way that air can flow outside from the rack causing air to flow from the rack through the duct, and providing an active noise control (ANC) system within the duct. Passive noise control may also be provided in the duct. At least one fan may be provided at an inlet of the duct. Fan speed may be controlled, in response to a climactic condition within the rack. The duct may comprise a back panel which is added on or a replacement for an existing back panel of the rack. A muffled inlet may be provided on another external surface of the rack.

Abstract: An acoustic field correction device corrects effect of frequency characteristics by indoor standing waves, determines a frequency range in which resonance due to standing waves occur, and adjusts an attenuation amount of a filter which suppresses the determined frequency range. In this adjustment, adjustment is made to reduce the amount of attenuation at the time of initial rise of the signal in the frequency range of the standing wave.

Abstract: A method of controlling noise from a six cylinder engine that can selectively use in separate operating modes either three cylinders, four cylinders, or all six cylinders, is provided that uses a noise cancellation system to provide a cancellation sound at a first frequency representative of the engine operating mode. When the vehicle changes, for example, from a three cylinder utilization mode to six cylinder utilization mode, the method extends the provision of the noise cancellation sound, at a frequency representative of three cylinder operation, beyond the time when three cylinder mode is changed to six cylinder mode. As a result, a residual “pop” noise associated with the vehicle exhaust, that is traditionally heard during the transition period is cancelled and no longer noticeable. The method also includes implementation of a waiting time before a providing cancellation sounds of different frequencies, to avoid amplitude mismatch.

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 silencer includes a cooling fan unit that cools a component which gives off heat during operation by blowing wind to the component and that outputs signal including rotational frequency information and information about timing of initiation of one cycle of noise; a storage section that stores an opposite phase waveform for the noise given off by the cooling fan unit; and a control section that detects the signal from the cooling fan unit and that adjusts the timing of initiation of one cycle of the opposite phase waveform. The configuration obviates a necessity for a microphone used for previously storing an opposite phase waveform and complicate arithmetic processing, and hence a phase lag in the opposite phase waveform can be prevented. Accordingly, the speaker can be disposed in proximity to the cooling fan. An opposite phase waveform output from the speaker can eliminate noise given off by the cooling fan over a wide range.

Abstract: The invention regards a scheme for generating a probe noise signal to be used in an anti feedback system of an audio system. The audio system comprises e.g. a microphone for capturing an audio signal, an audio signal processor for adaptation of the audio signal and a receiver for generation of an audible signal. According to an embodiment of the invention, a noise signal is injected into the audio signal path between the microphone and the receiver and used for estimating acoustical feedback, the noise signal being generated by the following steps: converting a digitized audio signal to the frequency domain, in order to obtain a series of magnitude and phase values, changing the phase values such that the phase of the resulting signal becomes less correlated, preferably substantially un-correlated, to the original signal, converting the magnitude and phase back to a time domain signal using the changed phase values. The invention may e.g. be used in a hearing aid, a headset or a pair of headphones.

Abstract: An audio system and a method to control the output of the audio system are provided. The audio system includes a source unit having an audio signal, a receiver to receive the audio signal and generate a cancellation signal to cancel the audio signal, a first speaker to output the audio signal, and a second speaker to output the cancellation signal.

Abstract: A system of microphones, signal processors, and loudspeakers provides enhanced comprehension of speech in noisy social events where the locations of participants are relatively constrained. Speech enhancement comprises both boosting sounds moderately at higher frequencies and delaying them to match the arrival of sounds directly from speakers. Virtual loudspeakers create the illusion for each listener that the boosted sounds come from the vicinity of each talker. Video cameras determine the head positions and facing directions of participants. Subgroups of participants having at least temporary conversational affinities can be identified. Such subgroups may overlap and change. Speech from talking participants is picked up by directional microphones and filtered, sorted, and relayed selectively via loudspeakers to listening participants identified as subgroup members, reinforcing and enhancing the naturally heard speech. More weight can be given to enhancing speech between affined participants.

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 noise cancelling headphone is described. The noise cancelling headphone utilizes a low power consuming noise cancellation circuit wherein an audio input signal is directly fed into the headphone without the use of an additional headphone amplifier. The noise cancelling circuit uses a microphone to pick up ambient noise and produces a signal which is equal in amplitude but opposite in polarity to the ambient noise signal. The resultant signal is mixed with the audio input signal and fed into the speakers of the headphone. This method is advantageous because it uses fewer components than conventional noise cancellation circuits and it also consumes less power due to the use of fewer components. The distortion of the audio input signal is also reduced since no amplification is performed to the audio input signal onboard the noise cancellation circuit.

Abstract: An active noise controller using an adaptive notch filter performs a coefficient update operation by using only a signal obtained by processing an error signal with ½ cycle of the frequency of noise to be reduced for a predetermined period. This eliminates the necessity of product operation for the coefficient update operation, and in turn significantly reduces an operation load.

Abstract: The invention is directed to a system and method for noise cancellation for an apparatus such as an electric motors or generator. The system may comprise a plurality of actuators, a plurality of phase controllers, each phase controller receiving an input signal representing a movement of an apparatus and outputting an output signal based on the input signal and at least one predetermined phase shift, and a plurality of amplifiers, each amplifier receiving an output signal from one of the phase controllers and outputting an amplified signal to drive one of the actuators. The method may comprise the steps of generating a first signal representing a movement of the apparatus, generating at least one second signal based on (a) the first signal, (b) at least one predetermined phase shift, and (c) at least one predetermined amplitude, and driving at least one actuator with the at least one second signal.

Abstract: An apparatus for processing an audio signal and method thereof are disclosed, by which a local dynamic range of an audio signal can be adaptively normalized as well as a maximum dynamic range of the audio signal. The present invention includes receiving a signal, by an audio processing apparatus; computing a long-term power and a short-term power by estimating power of the signal; generating a slow gain based on the long-term power; generating a fast gain based on the short-term power; obtaining a final gain by combining the slow gain and the fast gain; and, modifying the signal using the final gain.

Abstract: An acoustic-feedback detection apparatus includes: a first level detecting section configured to detect a signal level of sound signals obtained from a position in a sound-signal system in which a microphone and speaker are connected; a first extracting section configured to extract, from the sound signals of which the signal level is detected, signals in a band having a bandwidth predetermined for each of at least one predetermined center frequency; a second level detecting section configured to detect a signal level of the signals in each band, the signals being extracted by the first extracting section; and a determining section configured to determine whether or not acoustic feedback is occurring, on the basis of a threshold determined according to the signal level detected by the first level detecting section and a waveform of each signal level detected by the second level detecting section.

Abstract: The invention provides a sound source separation system, a sound source separation method, and an acoustic signal acquisition device which can precisely separate a target sound and a disturbance sound coming from an arbitrary direction, and which ensures miniaturization of a device.

Abstract: An active vibratory noise control apparatus reduces vibratory noise which is produced in the passenger compartment of a vehicle based on vibratory noise generated by a variable-cylinder internal combustion engine that can selectively be operated in a full-cylinder operation mode in which all of the cylinders are operated and a partial-cylinder operation mode in which some of the cylinders are out of operation. The active vibratory noise control apparatus has a partial-cylinder operation mode determining circuit for determining whether the variable-cylinder internal combustion engine is in the partial-cylinder operation mode or not. Depending on a determined result from the partial-cylinder operation mode determining circuit, a transistor is turned on or off to switch an amplifying circuit which drives a speaker into and out of operation.

Abstract: Some embodiments of the present invention provide a system that attenuates noise from a fan exhaust of a computer system. During operation, the system monitors the noise from the fan exhaust and calculates a frequency spectrum of the noise from the monitored noise. Next, the system generates an antiphase spectrum from the frequency spectrum and generates a flow of air which exhibits a property of the antiphase spectrum. Finally, the system directs the flow of air into the fan exhaust so that the noise is attenuated by a reduction of turbulence in the fan exhaust by the flow of air.

Abstract: An adaptive channel equalization technique and method for wideband passive receivers is disclosed that reduces and tends to minimize distortions caused by circuitry within passive digital receivers. This equalization architecture provides an adaptive equalization solution for a wideband passive channel that receives unknown signals from the RF environment both temporally and spectrally. A wideband chirp signal or calibration signal is periodically injected to capture the spectral response of the receiver channel as it varies from the distortions induced over time and temperature for synthesis of equalization filter coefficients. Thus, the channel equalization is performed independent of receiver signal source and is employed to minimize digital receiver signal measurement distortions across the passband by providing an equalization filter whose magnitude and phase response compensates for the channel distortions of the passive data collection system.

Abstract: Noise of a noise-producing object may be at least partially cancelled by a system that emits sound at a polarity substantially opposite to a polarity of detected noise and includes a member having elements disposed in the vicinity of a noise-producing object, some of the elements may be configured to emit noise, and some of the elements may be configured to detect noise and where a signal indicative of the detected noise may be received by a controller which sends a signal to cause at least some of the elements to emit sound at a polarity substantially opposite that of the detected noise, and includes an analyzer to determine when detected noise is indicative of one or more conditions of the noise producing object.

Abstract: In an active noise cancellation system having an adaptive filter that outputs a control signal, first and second speakers that emit a canceling signal generated based on the control signal, a microphone that detects an error signal, a correction filter that corrects the base signal by a correction value to generate a reference signal and a filter coefficient updater that successively updates the adaptive filter coefficient based on the error signal and reference signal such that the error signal is minimized, the correction value of the correction filter is set to a sum obtained by adding the transfer characteristic from the first speaker to the microphone, and a product obtained by multiplying the transfer characteristic from the second speaker to the microphone by the prescribed value, thereby enabling to reduce the number of microphones and avoid the increase in parts, the amount of work to provide complicated wiring to the microphones, and the computational load involved in updating the adaptive filter co

Abstract: A hearing aid circuit includes a correlation detector that detects correlation at a feedforward path input and that provides a correlation output to a phase shifter. The phase shifter introduces a phase shift along a feedforward path. A phase measurement circuit measures a phase shift at a feedforward path input, and provides a phase measurement output to an internal feedback processor. The internal feedback processor adjusts internal feedback as a function of the phase measurement to suppress coupling of external audio feedback along the feedforward path.

Abstract: A method and apparatus for adapting dual filters is disclosed. In one aspect, a method may include transforming a signal, adapting a first adaptive filter based on the transformed signal, estimating a delay of an impulse response based on the adaptation of the first filter, delaying a signal based on the estimated delay, and adapting a second adaptive filter based on the delayed signal. In one aspect, an echo or other unwanted signal may be reduced or cancelled based on the adaptation of the second filter.

Abstract: In a method for canceling unwanted signals from at least one external sound source, such as a loudspeaker, by means of headphones provided with microphones, at least known sound signals from the at least one external sound source are compensated by anti-phase sound signals. These sound signals simulate the at least known sound signals from said at least one external sound source in anti-phase. Said anti-phase sound signals are generated in the headphones in response to signals derived from audio input signals of the at least one external sound source in a filter device which is controlled by the resulting microphone signals.

Abstract: A synchronous detection and calibration system is provided for expedient calibration of differential acoustic sensors in a manufacturing and testing environment. By processing a series of sequentially received tones, respective portions of a system using differential acoustic sensors are tuned for optimum individual operation, following which corresponding control data are generated and stored for use in selecting among predetermined calibration vectors which establish and maintain optimum system operation.