Abstract: A crosstalk cancellation filter set configured for use in delivering binaural signals to human ears is provided. The crosstalk cancellation filter set includes a pressure matching system configured to perform spatial filtering or sound field control and an obstructed field model in communication with the pressure matching system. The crosstalk cancellation filter set is configured to take acoustic advantage of scattering effects and occlusional effects caused by violations to a free-field assumption, thereby delivering improved crosstalk cancellation acoustic displays to a listener without the use of headphones.

Abstract: An adaptive noise-canceling system generates an anti-noise signal from a noise reference signal with a feed-forward filter that filters the noise reference signal to produce the anti-noise signal. The feed-forward filter has a first response controlled by a set of first coefficients. The adaptive noise-canceling system includes a measurement subsystem for measuring a characteristic of an acoustic environment of the adaptive noise-canceling system, a classifier for classifying the characteristic of the acoustic environment by analyzing an output of the measurement subsystem, and a controller that provides the set of first coefficients to the feed-forward filter in conformity with an output of the classifier.

Abstract: The present disclosure is related to a method and system for a room calibration in a speaker system using an internal microphone. The method comprises calculating an impulse response of a sound signal received at an internal microphone from at least one speaker, and performing the room calibration based on the calculated impulse response.

Abstract: Embodiments of the present application provide a method and system for active noise control, which can meet different needs of different consumers on sound quality of headphones. The method includes: determining an expected noise control curve of performing active noise control on a target object; determining a target filter according to the expected noise control curve and a filter model; and performing noise control processing on an external noise signal using the target filter.

Abstract: The present invention includes: a housing that includes an arrangement case in which an internal space is formed, and a sound guide tube in which a sound conduction space is formed; a feedback microphone to which an external sound is input; a first speaker unit that outputs a sound; and a second speaker unit that outputs a sound in an output band different from an output band of the sound output from the first speaker unit. The housing has inside a first space and a second space, the feedback microphone and the first speaker unit are arranged in the first space, the second speaker unit is arranged in the second space, and an equalizer that partitions the first space and the second space is disposed between the first speaker unit and the second speaker unit.

Abstract: The present disclosure provides a method for evaluating an electronic device. The method comprises determining, with an acoustic tube, a value of a first parameter, the value of the first parameter being indicative of the acoustic impedance of a reference termination. The method further comprises determining, with the acoustic tube, a value of a second parameter, the value of the second parameter being indicative of the acoustic impedance of the reference termination, when occluded by the electronic device. The method then comprises calculating a value of a third parameter, the value of the third parameter being indicative of the acoustic impedance of the electronic device, based on the value of the first parameter and the value of the second parameter.

Abstract: A head-mounted audio output apparatus comprising: a hybrid audio system comprising multiple transducers, wherein the hybrid audio system is configured to render sound for a user of the apparatus into different audio output channels using different associated transducers; means for automatically changing a cut-off frequency of a first one of the audio output channels in dependence upon the transducer associated with the first one of the audio output channels.

Abstract: An earmuff module of a headphone includes a back cover, a sound-receiving hole, a microphone assembly, and an earmuff. The back cover includes a peripheral side wall. The sound-receiving hole is formed on the peripheral side wall of the back cover and penetrates through the peripheral side wall. The microphone assembly is disposed on an inner surface of the peripheral side wall and corresponds to the sound-receiving hole, and is acoustically connected with the sound-receiving hole. The earmuff is detachably assembled on the back cover, and the earmuff includes a foam and a wrapping cover. The wrapping cover includes an extension part and a covering part. The covering part covers the foam. The extension part extends from one end of the covering part to an outer surface of the peripheral side wall and covers the sound-receiving hole. The microphone assembly is located within a range covered by the extension part.

Abstract: An audio system for an ear mountable playback device comprises a speaker, an error microphone configured to predominantly sense sound being output from the speaker and a further microphone configured to predominantly sense ambient sound. The system further comprises a first noise filter coupling the further microphone to the speaker, a second noise filter coupling the error microphone to the speaker and an adaptation engine. The adaptation engine is configured to adapt a response of the first noise filter depending on error signals from at least the error microphone, estimate a leakage condition from the response of the first noise filter, and adapt a response of the second noise filter depending on the estimated leakage condition.

Abstract: Aspects relate to systems and methods for dynamic active noise reduction including at least a sensor configured to sense a physiological characteristic of a user and transmit a physiological signal correlated to the sensed physiological characteristic, at least an environmental microphone configured to transduce an environmental noise to an environmental noise signal, a processor configured to receive the environmental noise signal, generate a noise-reducing sound signal as a function of the environmental noise signal, and, modify the noise-reducing sound signal as a function of the physiological signal, and a speaker configured to transduce a noise-reducing sound from the modified noise-reducing sound signal.

Abstract: An audio system for an ear mountable playback device includes a speaker, an error microphone, which senses sound being output from the speaker, and a sound control processor. The processor is configured for controlling and/or monitoring a playback of a detection signal or a filtered version of the detection signal via the speaker, recording an error signal from the error microphone, and determining whether the playback device is in a first state, where the playback device is worn by a user, or in a second state, where the playback device is not worn by a user, based on processing of the error signal.

Abstract: A noise reduction system is provided. The noise reduction system may include a sub-band noise sensor, a plurality of sub-band noise reduction modules, and an output module. The sub-band noise sensor may be configured to detect a noise and generate a plurality of sub-band noise signals in response to the detected noise. Each of the plurality of sub-band noise signals may have a distinctive sub-band of the frequency band of the noise. Each of the sub-band noise reduction modules may be configured to receive one of the sub-band noise signals from the sub-band noise sensor and generate a sub-band noise correction signal for reducing the received sub-band noise signal. The output module may be configured to receive the sub-band noise correction signals and output a noise correction signal for reducing the noise based on the sub-band noise correction signals.

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

Abstract: An active noise control apparatus of vehicles capable of making it difficult for a passenger in a vehicle to hear the voice of another passenger, achieving privacy protection, and a method of controlling the same are disclosed. The active noise control method includes primarily determining a noise level based on a first microphone signal input through a microphone corresponding to a first seat, secondarily determining whether to output an anti-noise signal generated based on the first microphone signal and the magnitude of the anti-noise signal based on the noise level and the level of the first microphone signal, and outputting the anti-noise signal through a headrest speaker of a second seat in response to the secondary determining.

Abstract: An ear cup housing has several reference microphones, an error microphone and a speaker. A processor drives the speaker for acoustic noise cancellation and transparency, by processing the microphone signals, and performs an oversight process by adjusting the reference microphone signals in response to detecting wind noise events and scratch events. In another aspect, the ear cup housing has an outside face that is joined to an inside face by a perimeter and the reference microphones are on the perimeter. Other aspects are also described and claimed.

Abstract: A hearing device system includes: first and second hearing devices, each of which comprising at least one microphone, a primary antenna, and a speaker; the hearing device system configured to communicate with an electronic device configured to establish a call between the user and a far-end person; the hearing device system configured to determine a first noise level, N1, of sound received by the at least one microphone of the first hearing device, and a second noise level, N2, of sound received by the at least one microphone of the second hearing device; the hearing device system configured to transmit a voice signal to the electronic device, the voice signal being based on a voice of the user captured by the at least one microphone of the first hearing device when N1<N2, or captured by the at least one microphone of the second hearing device when N1>N2.

Abstract: An apparatus for hearing protection comprises a pair of earpads, a band, microphones, speakers, vibration generators, and a processing unit. Each of the earpads is placed over an ear of the user. The band extends between the pair of earpads. The microphones convert acoustic signals into electrical signals. The speakers are located on each of the pair of earpads and direct sound towards the ear. The vibration generators are located on at least one of the pair of earpads and generate vibratory feedback to the user. The processing unit is connected to the microphones, the speakers, and the vibration generators, and compares first parameters of the electrical signals from the microphones with second parameters of predetermined warning sounds to determine whether the electrical signals comprise one or more of the predetermined warning sounds.

Abstract: The present disclosure relates to the technical field of earphone and provides to an active noise reduction earphone. The active noise reduction earphone includes an earphone shell, a speaker, a sound outlet mouth, a first feedback digital microphone, a second feedback digital microphone and a sound collecting channel. Herein, the speaker divides the earphone shell into the front speaker cavity and the back speaker cavity; the sound outlet mouth is arranged to be faced to the speaker to output the sound emitted by the speaker; the first feedback digital microphone is arranged at the first noise reduction sound collecting hole preset in the back speaker cavity to collect external ambient noise; the sound in the ear canal is collected through the sound collecting channel, and the second feedback digital microphone isolates the sound collecting channel from the front speaker cavity.

Abstract: An audio system for a headset includes a plurality of speakers and an audio controller. The plurality of speakers may be in a dipole configuration that cancel sound leakage into a local area of the headset. The controller filters audio content presented by the plurality of speakers to further mitigate leakage of audio content into the local area. The audio determines sound filters based on environmental conditions, such as ambient noise levels, as well as based on the audio content being presented.

Abstract: A bone conduction audio apparatus includes at least one ear hook assembly. A main circuit board is provided in the ear hook assembly. Each ear hook assembly includes an operating unit, a line concentrator and a bone conduction transducer. Each operating unit is electrically connected with corresponding line concentrator by contact springs or connecting wires, and connected with the main circuit board via the line concentrator. Each bone conduction transducer is electrically connected with the main circuit board via corresponding line concentrator. A controller of the main circuit board receives touch signals from all operating units to determine and initiate relating earphone operating. The bone conduction audio apparatus adopts bilateral triggering interaction mechanism. The line concentrator is combined with the suspended bone conduction transducer.

Abstract: A headphone device comprising active noise cancellation means (ANC) having a feedback (FB) signal path, a feed forward (FF) signal path and a sidetone signal path, where the headphone is provided with a control member (1, 11) that can be displaced or rotated between opposite positions, where the control member (1, 11) is configured such that the gain of the FF signal path and the gain of the sidetone signal path are controllable by the control member (1, 11) in such manner that when the control member (1, 11) is at one extreme position, the gain of the FF signal path is maximum and the gain of the sidetone signal path is minimum and when the control member (1,11) is at the opposite extreme position, the gain of the FF signal path is minimum and the gain of the sidetone signal path is maximum.

Abstract: A computer-implemented method for automatically optimizing a hybrid active noise cancellation system, the hybrid active noise cancellation system comprising a feedback filter and a feedforward filter, the method comprising optimizing the feedforward filter, thereby optimizing the hybrid active noise cancellation system, wherein optimization of the feedforward filter is dependent on the feedback filter.

Abstract: A method for reducing noise includes: obtaining a priori signal-to-noise ratio of air-bone integration, the priori signal-to-noise ratio of air-bone integration being obtained by integrating air conduction parameters of the current frame, bone conduction parameters of the current frame and air conduction noise parameters of the current frame; calculating a noise reduction gain according to the priori signal-to-noise ratio of air-bone integration; and performing noise reduction operation according to the noise reduction gain and the air conduction parameters of the current frame.

Abstract: A user content audio signal is converted into sound that is delivered into an ear canal of a wearer of an in-ear speaker, while the in-ear speaker is sealing off the ear canal against ambient sound leakage. An acoustic or venting valve in the in-ear speaker is automatically signaled to open, so that sound inside the ear canal is allowed to travel out into an ambient environment through the valve, while activating conversion of an ambient content audio signal into sound for delivery into the ear canal. Both user content and ambient content are heard by the wearer. The ambient content audio signal is digitally processed so that certain frequency components have been gain adjusted, based on an equalization profile, so as to compensate for some of the insertion loss that is due to the in-ear speaker blocking the ear canal. Other embodiments are also described and claimed.

Abstract: In one aspect a method that includes receiving an input signal captured by one or more first sensors associated with an active noise reduction (ANR) device, and processing the input signal using a first filter disposed in an ANR signal path to generate a first signal for an acoustic transducer of the ANR device. The input signal is processed in a pass-through signal path disposed in parallel with the ANR signal path to generate a second signal for the acoustic transducer, wherein the pass-through signal path allows a portion of the input signal to pass through to the acoustic transducer in accordance with a variable gain. One or more second sensors detect an existence of a condition likely to cause instability in the pass-through signal path, and in response, the variable gain is adjusted. A driver signal for the acoustic transducer is generated using an output based on the adjusted gain.

Abstract: An apparatus, method and computer program product for: providing spatial audio signals for output for a first user via a first audio device and a second audio device, receiving an indication of deactivation of the second audio device, receiving an indication that the second audio device is re-activated by a second user, and performing, in response to receiving the indication that the second audio device is re-activated by the second user, a modification of the spatial audio signals.

Abstract: Aspects include identifying each of a plurality of audio sources proximate to a user wearing a headset. The audio sources include a primary audio source and a plurality of background audio sources. Aspects include causing the headset to play a set of audio sources to the user by causing each audio source of the set to be unfiltered by the headset. Aspects include determining an acceptance level of the user. Aspects also include determining a background noise filtering adjustment based on the acceptance level and the set of audio sources being played by the headset to the user. Aspects also include causing the headset to adjust a filtering of one or more of the plurality of background audio sources by the headset based on the background noise filtering adjustment.

Abstract: A first input signal captured by one or more sensors associated with an ANR headphone is received. A frequency domain representation of the first input signal is computed for a set of discrete frequencies, based on which a set of parameters is generated for a digital filter disposed in an ANR signal flow path of the ANR headphone, the set of parameters being such that a loop gain of the ANR signal flow path substantially matches a target loop gain. Generating the set of parameters comprises: adjusting a response of the digital filter at frequencies (e.g., spanning between 200 Hz-5 kHz). A response of at least 3 second order sections of the digital filter is adjusted. A second input signal in the ANR signal flow path is processed using the generated set of parameters to generate an output signal for driving the electroacoustic transducer of the ANR headphone.

Abstract: A method for tuning filter parameters of a noise cancellation enabled audio system with an ear-mountable playback device comprising a speaker and a feedback noise microphone located in proximity to the speaker comprises provision of acoustic transfer functions between the speaker and the feedback noise microphone, between the speaker and an eardrum, between an ambient sound source and the eardrum and between the ambient sound source and the feedback noise microphone. The parameters of a feedback filter function, which is designed to process a feedback noise signal, are tuned. A noise cancellation performance of the audio system at the eardrum is determined based on each of the acoustic transfer functions and on the feedback filter function.

Abstract: Methods for calibrating active noise-cancelling headphones, including placing the active noise-cancelling headphones on a measuring device; exciting the active noise-cancelling filter; measuring one or more relevant transmission pathways selected from x(n), m(n), and p(n) for feedforward and/or h(n) for feedback; defining at least one goal function for feedforward or feedback; calculating a complementary function for the defined goal function for at least one branch of the active noise-cancelling filter; calculating an impulse response of the complementary function from the measurements of the relevant transmission pathways; approximating operating parameters for the active noise-cancelling filter using the Prony method; and implementing the approximated operating parameters in the active noise-cancelling filter on the signal processor in order to create an approximated complementary active noise-cancelling filter, thereby calibrating the active noise-cancelling headphones.

Abstract: A crosstalk cancellation filter set configured for use in delivering binaural signals to human ears is provided. The crosstalk cancellation filter set includes a pressure matching system configured to perform spatial filtering or sound field control and an obstructed field model in communication with the pressure matching system. The crosstalk cancellation filter set is configured to take acoustic advantage of scattering effects and occlusional effects caused by violations to a free-field assumption, thereby delivering improved crosstalk cancellation acoustic displays to a listener without the use of headphones.

Abstract: Playback devices such as headphone devices can include an earpiece configured to be positioned adjacent a user's ear. The earpiece can include a transducer having a diaphragm configured to face toward the user's ear when the earpiece is positioned adjacent the user's ear, as well as an outlet vent in fluid communication with the transducer and a microphone. A support member within the earpiece includes a first opening aligned with the microphone and a second opening aligned with the outlet vent. An acoustic mesh extends over the first opening and the second opening, wherein the mesh has a substantially uniform acoustic impedance.

Abstract: An ear-mountable listening device includes a plurality of electroacoustic transducers, a manifold, and an output port. The plurality of electroacoustic transducers emit audio in response to an audio signal. The plurality of electroacoustic transducers includes a first transducer and a second transducer. The manifold is coupled to the plurality of electroacoustic transducers. The manifold is shaped to position the first transducer and the second transducer to face one another and form a front cavity disposed between the first transducer and the second transducer. The output port is coupled to the manifold to direct the audio from the front cavity into an ear when the plurality of electroacoustic transducers emits the audio.

Abstract: An audio apparatus, e.g. for rendering audio for a virtual/augmented reality application, comprises a receiver (201) for receiving audio data for an audio scene including a first audio component representing a real-world audio source present in an audio environment of a user. A determinator (203) determines a first property of a real-world audio component from the real-world audio source and a target processor (205) determines a target property for a combined audio component being a combination of the real-world audio component received by the user and rendered audio of the first audio component received by the user. An adjuster determines a render property by modifying a property of the first audio component indicated by the audio data for the first audio component in response to the target property and the first property. A renderer (209) renders the first audio component in response to the render property.

Abstract: An example loudspeaker arrangement includes a seat configured to support a listener sitting in the seat so that a head of the listener is in a listening position; and a loudspeaker array secured to the seat and disposed in a position in front of a backrest of the seat and to the side of the head when the head is in the listening position. The loudspeaker array includes at least one loudspeaker and has a main broadcasting axis representative of a main broadcasting direction, the main broadcasting direction of the loudspeaker array pointing to the head.

Abstract: An earbud system for reducing noise is disclosed. The earbud system comprises an analog to digital converter to convert analog audio signals of a sound captured by one or more sound sensors into digital audio signals, and one or more processors to filter one or more raw bits with a specific frequency band from the digital audio signals to obtain filtered digital audio signals and extract human audible frequency bands from the filtered digital audio signals. The processors predict and/or classify, using an artificial intelligence based mechanism, the extracted human audible frequency bands into ambient noise corresponding to a first set of frequencies and desired sound, to be heard by the user, corresponding to a second set of frequencies. The processors further generate anti-phase signals for a first set of frequencies to reduce noise, and audible phase signals for the second set of frequencies.

Abstract: Various aspects include wearable audio devices wearable audio devices with a control platform for managing external device interaction. In some particular aspects, a wearable audio device includes: an accessory port; at least one processor; and memory including multiple sets of active noise reduction (ANR) configurations (or more generally, multiple profiles), the memory including instructions executable by the at least one processor, where the instructions are configured to: select a first ANR configuration (or more generally, a first profile) upon powering on the wearable audio device, the selection of the first ANR configuration (or first profile) based on an accessory connected to the accessory port, and automatically switch to a second ANR configuration (or more generally, a second profile) in response to a trigger, where the second ANR configuration (or second profile) is different from the first ANR configuration (or first profile).

Abstract: Digital audio signal processing techniques used to provide an acoustic transparency function in a pair of headphones. A number of transparency filters can be computed at once, using optimization techniques or using a closed form solution, that are based on multiple re-seatings of the headphones and that are as a result robust for a population of wearers. In another embodiment, a transparency hearing filter of a headphone is computed by an adaptive system that takes into consideration the changing acoustic to electrical path between an earpiece speaker and an interior microphone of that headphone while worn by a user. Other embodiments are also described and claimed.

Abstract: For example, an apparatus for Active Acoustic Control (AAC) of an open acoustic headphone may include an input to receive input information including a residual-noise input including residual-noise information corresponding to a residual noise sensor of the open acoustic headphone, and a noise input including noise information corresponding to a noise sensor of the open acoustic headphone; a controller configured to determine a sound control pattern configured for AAC of the open acoustic headphone, the controller configured to identify a mounting-based parameter of the open acoustic headphone based on the input information, and to determine the sound control pattern based on the mounting-based parameter, the residual-noise input, and the noise input; and an output to output the sound control pattern to an acoustic transducer of the open acoustic headphone.

Abstract: A first variable filter receives a sound of a second seat audio source as an input and generates a cancel sound for canceling the sound of the second seat audio source at a first seat. The transfer functions of the first variable filter and the second variable filter are updated such that the level of a signal obtained by subtracting the output of the auxiliary filter that generates a correction signal for correcting the difference between the positions of the first seat microphone and the first seat and the output of the second variable filter that receives the sound of the first seat audio source from the output of the first seat microphone is minimized. While the level of the signal exceeds a threshold, the signal is relayed to the second seat as a spoken voice.

Abstract: A hearing device may include a housing configured to be at least partially inserted into an ear canal of a user and comprising a venting channel, wherein the venting channel is configured to provide for venting between an inner region of the ear canal and an ambient environment outside the ear canal through the venting channel; an acoustic valve comprising a valve member moveable relative to the venting channel between different positions; a sound detector configured to provide an audio signal representative of a detected sound; a processor configured to determine a characteristic from the audio signal and to classify the audio signal by assigning the audio signal to a class from a plurality of predetermined classes depending on the determined characteristic; and an output transducer configured to be acoustically coupled to the inner region of the ear canal.

Abstract: An illustrative controller includes: a transmitter to drive the acoustic transducer to generate acoustic bursts; a receiver to sense a response of the acoustic transducer to echoes; and a processing circuit coupled to the transmitter and to the receiver, the processing circuit configured to convert said received response into output data by: correlating said response to a driving signal to obtain a correlation response; distinguishing peak areas from non-peak areas in said correlation response; deriving a noise level in a portion of said correlation response based on the non-peak areas within said portion; calculating a signal to noise ratio (SNR) for a peak signal within the portion as a ratio of a peak value for the peak signal to the noise level in said portion of said correlation response; and accepting the peak signal as an echo only if the SNR for said peak signal exceeds a predetermined threshold.

Abstract: To provide an out-of-head localization system, a filter generation device, a method, and a program capable of appropriate processing, an out-of-head localization system according to this embodiment includes a measurement device that measures transfer characteristics by using a microphone worn on a user's ear before the user U sits on a seat, an out-of-head localization device that is installed in the seat and performs out-of-head localization by using a filter appropriate to the transfer characteristics, and a server terminal that transmits the filter appropriate to the transfer characteristics to the out-of-head localization device on the basis of identification information of the user U.

Abstract: Active noise cancellation systems and methods include a feedforward path configured to receive a reference signal comprising ambient noise and adaptively generate an anti-noise signal to cancel the ambient noise and comprising an adaptive gain component configured to adaptively adjust a gain of the anti-noise signal, and a logic device configured to determine a leakage profile based on the adaptive gain component. The feedforward path includes a feedforward adaptive filter tuned to generate the anti-noise signal corresponding to the reference signal in accordance with the determined leakage profile. The leakage profile is selected from a plurality of stored leakage profiles that are tuned for a corresponding gain, and which corresponds to an ear coupling condition associated with a fit between the active noise cancellation system and a user. An adaptive transparency filter receives the reference signal and generates an ambient inclusion signal for output to a user.

Abstract: An audio system for a wearable device dynamically updates acoustic transfer functions. The audio system is configured to estimate a direction of arrival (DoA) of each sound source detected by a microphone array relative to a position of the wearable device within a local area. The audio system may track the movement of each sound source. The audio system may form a beam in the direction of each sound source. The audio system may identify and classify each sound source based on the sound source properties. Based on the DoA estimates, the movement tracking, and the beamforming, the audio system generates or updates the acoustic transfer functions for the sound sources.

Abstract: There is provided a headphone device including: an external magnet type magnet unit that is disposed outside a voice coil, and vibrates the voice coil; and a diaphragm that is vibrated by vibration of the voice coil, and formed of a material in which a dome section having an outward concave shape on an inner circumference of the voice coil is continuous with an edge section outside the voice coil.

Abstract: An electronic device and method are disclosed. The electronic device includes a first microphone, a second microphone, a memory; and a processor. The processor implements the method, including: determining whether a voice is detected in a first sound signal detected by the first microphone; determine whether a present recording period is a voice period or a silent period based on the determination, when the present period is the silent period, receive a second sound signal via the second microphone and analyze a noise signal included therein, remove noise signals from one of the first and second sound signals, based on characteristics of the voice period or the analyzed noise signal, and combine the first and second sound signal into an output signal and transmit the output signal to an external device.

Abstract: A system for detecting feedforward instability in a wearable audio device. The audio device includes an electro-acoustic transducer that is configured to develop sound for a user, a housing that holds the transducer, a feedforward microphone that is configured to detect sound outside of the housing and output a microphone signal, and an opening in the housing that emits sound pressure from the transducer that can reach the microphone. A feedforward instability detector is configured to apply two filters to the microphone signal. A first filter passes more energy in a frequency band than does a second filter, to develop a filtered signal. The filtered signal is compared to the microphone signal outside of the frequency band, to develop a comparison signal that is indicative of feedforward instability in the frequency band.

Abstract: Provided is a headphone device including a housing, an audio input unit that is arranged to be separated from the housing and collects audio to generate an audio signal, a holding unit that abuts on a cavum concha or an inner wall of an ear canal of a user and holds the audio input unit in a space closer to an eardrum side than a tragus, in a state of being worn by the user, a wired connection unit that connects the housing and the audio input unit in a wired manner, a signal processing unit that generates a noise cancellation signal for an external sound based on the audio signal generated by the audio input unit, and generates an output signal based on the generated noise cancellation signal, and an audio output unit that outputs audio based on the output signal.

Abstract: A sound producing structure includes: a frame body, a magnetic circuit system, a first diaphragm, and a second diaphragm. The frame body includes a receiving cavity, and the receiving cavity includes a first opening and a second opening that are located on two opposite sides of the frame body. The magnetic circuit system is located in the receiving cavity, and the magnetic circuit system includes a first magnetic channel and a second magnetic channel that are isolated from each other. The first diaphragm is disposed facing the first opening, a first voice coil is disposed on the first diaphragm, and a portion of the first voice coil extends into the first magnetic channel. The second diaphragm is disposed facing the second opening, a second voice coil is disposed on the second diaphragm, and a portion of the second voice coil extends into the second magnetic channel.