A hearing device

Abstract

A hearing device is disclosed comprising: an input unit; an output unit; first and second spatial filters, each spatial filter connected to the input unit and configured to provide a respective first and second spatial filtered signal based on a plurality of electrical input signals and configurable beamformer weights; wherein the first spatial filter implements at a given time a feedback cancelling beamformer towards the user's environment or a target preserving, noise cancelling beamformer; the second spatial filter implements at a given time a feedback cancelling beamformer towards the user's mouth or a self voice beamformer; and the second spatial filter is controlled by a self voice presence control signal, and / or a far end talker presence control signal, and / or a telephony mode control signal.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201910554253.6, filed on June 25, 2019, entitled "Hearing Device Including Feedback Reduction System". Technical Field

[0002] This application relates to the field of hearing devices, such as hearing aids, and particularly to feedback management. Background Technology

[0003] In hearing aids at the current technological level, acoustic gain is limited by acoustic feedback. If the loop gain exceeds 0 dB, acoustic feedback can cause the hearing aid to oscillate. For most hearing aid types, the level of feedback depends on the size of the opening in the part of the hearing aid located in the user's ear canal (e.g., the size of the vent in the earmold) and also on the distance between the opening and the microphone. For in-the-ear (ITE) hearing aids, the microphone is placed in the user's ear canal or cochlea. The distance between the vent and the microphone is much smaller compared to behind-the-ear (BTE) or resonant-in-the-ear (RITE) hearing aids (HI), because in BTE or RITE hearing aids, the microphone is typically placed further away from the speaker (receiver), for example, behind the ear. Thus, for ITE HI, feedback is generally a larger problem compared to BTE / RITE HI. Summary of the Invention

[0004] Hearing device

[0005] In one aspect of this application, a hearing device, such as a hearing aid, is provided, configured to be located at or in the user's ear. The hearing device includes:

[0006] - Input unit, including multiple input converters for providing corresponding electrical input signals representing sounds in the user's environment;

[0007] - Output unit, including an output transducer for providing a stimulus that can be perceived as sound by a user based on the electrical input signal or a processed version thereof;

[0008] - A (configurable) spatial filter connected to the input unit and the output unit is configured to provide a spatially filtered signal based on multiple electrical input signals and configurable beamformer weights.

[0009] The hearing device also includes:

[0010] - A spatial filter controller configured to apply beamformer weights from a first and / or second different set to the plurality of electrical input signals (or signals derived therefrom).

[0011] The first set of beamformer weights is used to provide spatial filtering of the sound from the output converter, and the second set of beamformer weights is used to provide spatial filtering of the external sound field (external meaning in the environment far from the user).

[0012] This can provide improved hearing devices.

[0013] Hearing devices include or are constituted by a portion (referred to as an ITE portion) adapted to be fully or partially located in or within a user's ear canal. An ITE portion may include a standard housing or a housing custom-made for a particular user's ear. The housing of the ITE portion may enclose or mechanically support some or all components of the hearing device. The housing of the ITE portion may include an earmold, such as a custom-made earmold. The housing of the ITE portion, for example, may include (or be provided after installation) acoustic ventilation channels (referred to as "vents"), possibly two or more (e.g., distributed) ventilation channels, for example, to reduce the occlusion effect. The ventilation channels are configured to equalize the pressure difference between the environment and the residual cavity between the housing of the ITE portion and the eardrum (when the ITE portion is installed and in operation). This reduces the occlusion effect. Vents can be formed in many different ways, for example, to reduce the occlusion effect while minimizing sound leakage to the environment.

[0014] The hearing device may include two input transducers. In an embodiment, the hearing device includes only input transducers. The two input transducers may be located in the ITE section, for example, together with the output transducer.

[0015] The input unit is configured to be located in or near the user's ear, such as in the ear canal or cochlea (thus benefiting from the frequency shaping of acoustic signals by the auricle). In an embodiment, the ITE portion includes the input unit. Therefore, multiple input transducers may be located in the ITE portion. In an embodiment, the ITE portion includes at least one of multiple input transducers, such as at least two, or all of the multiple input transducers. In an embodiment, the input unit includes two or three input transducers, such as microphones.

[0016] The output transducer can be located in the ITE section. The output transducer can be located in the BTE section, which is suitable for placement at or behind the user's ear (auricle). The output transducer can be located on or at the side bar of the eyeglass frame.

[0017] The first set of (typically complex-valued) beamformer weights is configured to reduce the amount of sound reaching the input converter from the output converter (even if acoustic feedback is minimized). The second set of (typically complex-valued) beamformer weights is configured, for example, to preserve sound from the target direction (e.g., in the acoustic far field) while attenuating sound from other directions (or attenuating sound from the target direction less than sound from other directions). In an embodiment, the spatial filter controller is configured to apply a combination of the first and second sets of beamformer weights. It may be of interest to provide a gradient between the two sets of weights to avoid abrupt changes in beamformer weights from one set to the other (e.g., switching between the first and second sets of beamformer weights), which could become audible. In an embodiment, the first and second sets of beamformer weights are configured to keep sound from the target direction unchanged (e.g., the direction of the target sound source in the acoustic far field).

[0018] The first and second sets of beamformer weights may have complex values. One or more (such as all) of the first and second sets of beamformer weights may have real values.

[0019] The first and second sets of beamformer weights can be applied at different times. In an embodiment, only one of the first and second sets of beamformer weights is applied at a given time and in a given frequency band. In other words, in an embodiment, only one of the first and second sets of beamformer weights is active at the given time (in a given frequency band). This is necessary, for example, in solutions where only electrical input signals from two independent input converters are available for beamforming (but is also feasible in solutions involving two or more, such as three or four input converters like microphones).

[0020] However, it may be advantageous to gradually change the beamformer weights from one set to another (gradual change). The spatial filter controller can be configured to gradually change the beamformer weights from one set to another (e.g., from the first set of beamformer weights to the second set or from the second set to the first set).

[0021] Simultaneous application of two sets of beamformer weights can also be advantageous. However, this requires that electrical input signals from more than three independent input converters be available for beamforming. In an embodiment, the first and second sets of beamformer weights are applied simultaneously in at least one frequency band (e.g., in all frequency bands).

[0022] The input unit may include a corresponding filter bank configured to provide the electrical input signal as, for example, a digitized sub-band signal in a time-frequency representation (k,m), where k and m are the frequency and time exponents, respectively.

[0023] The hearing device can be configured such that the weights of the first and second sets of beamformers vary with frequency. In an embodiment, the first set of beamformer weights is applied in one frequency band, and the second set of beamformer weights is applied in another frequency band. In other words, at a given point in time, beamformer weights from the first set of beamformer weights can be applied in some frequency bands, while beamformer weights from the second set of beamformer weights can be applied in other (e.g., complementary, e.g., all other) frequency bands.

[0024] The hearing device can be configured such that the weights of a first and / or second set of beamformers are adaptively determined. In one embodiment, the hearing device is configured such that the weights of the first set of beamformers adapt to feedback changes. In another embodiment, the hearing device is configured such that the weights of the second set of beamformers adapt to noise. In yet another embodiment, the weights of both the first and second sets of beamformers are adaptive. In yet another embodiment, the hearing device is configured such that the target direction is adaptively determined (this subject matter is covered in our pending patent application EP3267697A1).

[0025] The hearing device can be configured such that a first set of beamformer weights is applied only in selected frequency bands. In an embodiment, the first set of beamformer weights is applied only in pre-selected frequency bands (e.g., in the band where feedback is expected, determined by the hearing aid type, and / or during fitting, or adaptively determined during use, e.g., by a feedback estimator that estimates the current risk of feedback at the sub-band level).

[0026] The hearing device may include a feedback estimator configured to provide an estimate of the current level of feedback from at least one of the output converters to the input converters. The feedback estimator may be configured to provide an estimate of the current level of feedback from the output converter to at least one of the input converters in one or more frequency bands, such as one or more frequency bands between 1 kHz and 8 kHz, or between 1.5 kHz and 4 kHz.

[0027] The feedback estimator can be configured to provide feedback estimates of the current feedback paths from the output converter to at least two input converters, such as all of the input converters. The estimates of the feedback paths can be provided as a frequency transfer function from the output converter to a given input converter (e.g., specified at multiple different frequencies). The estimates of the feedback paths can be provided as an impulse response from the output converter to a given input converter.

[0028] In one embodiment, the hearing device is configured to adaptively determine (or select) an appropriate set of beamformer weights based on the input level (e.g., the level of an electrical input signal from an input converter). The spatial filter controller may be configured to adaptively select an appropriate (e.g., predetermined) set of beamformer weights based on the input levels of one or more of a plurality of input converters (e.g., among two or more sets of beamformer weights stored in memory). The spatial filter controller may be configured to adaptively select among two or more sets of beamformer weights (including first and second sets of beamformer weights).

[0029] The hearing device can be configured to determine (or select) an appropriate set of beamformer weights based, for example, solely on the input level without input from the feedback estimator (e.g., the level of the electrical input signal from the input converter). The hearing device can also be configured to determine (or select) an appropriate set of beamformer weights based on the hearing device's operating mode, such as communication mode (e.g., telephone mode), feedback risk mode, or normal (multi-environment) mode.

[0030] The hearing device may include at least one level estimator for estimating the input level of at least one electrical input signal, wherein a spatial filter controller is configured to apply first and / or second different sets of beamformer weights to a plurality of electrical input signals based on the estimated input level. In an embodiment, the hearing device includes a corresponding level estimator configured to provide a level estimate of the current input signal for at least two of the plurality of electrical input signals, such as each of them. Alternatively or additionally, the hearing device may include a level estimator for estimating the current level of a spatially filtered signal. The hearing device may include at least one level estimator for estimating the input level of at least one of the electrical input signals, wherein a spatial filter controller is configured to apply a second set of beamformer weights to the plurality of electrical input signals when the input level of the at least one electrical input signal is higher than an input threshold level. In an embodiment, the input threshold level is equal to 60 dB or higher, such as 70 dB or higher. In an embodiment, the spatial filter controller is configured to disable the first set of beamformer weights when the input level of the at least one electrical input signal is higher than the input threshold level. In one embodiment, the spatial filter controller is configured to enable a first set of beamformer weights when the input level of the at least one electrical input signal is below an input threshold level. In another embodiment, the spatial filter controller is configured to disable a second set of beamformer weights when the input level of the at least one electrical input signal is below an input threshold level.

[0031] The input threshold levels may differ for at least a portion of the multiple electrical input signals from respective input transducers (such as microphones). For a given input transducer, the input threshold level may depend on the input transducer's location within the hearing device (e.g., its location relative to an output transducer, such as the distance of the path from the output transducer to the input transducer and / or the acoustic impedance). In embodiments, a set of input level thresholds is determined for each frequency band of each input transducer (and may be accessed by a spatial filter controller, e.g., stored in the hearing device's memory).

[0032] The hearing device may include a loop gain estimator for estimating the current loop quantity of a feedback loop formed by a forward path between an input unit and an output unit and an external feedback path from the output unit to the input unit, and a spatial filter controller configured to apply first and / or second different sets of beamformer weights to the plurality of electrical input signals based on the estimated current loop quantity. The hearing device may include a loop gain estimator for estimating the current loop quantity of a feedback loop formed by a forward path between an input unit and an output unit and an external feedback path from the output unit to the input unit. The spatial filter controller may be configured to disable the first set of beamformer weights when the current loop quantity is below a loop quantity threshold. In an embodiment, the loop quantity threshold is equal to or less than 0 dB.

[0033] Hearing aids may include, for example, a compressor for applying a compression amplification algorithm to the signal in the forward path of the hearing aid. The compressor is configured to apply compression amplification based on a level estimate of the electrical input signal (e.g., from a microphone) or based on a beamforming signal. The compressor may be configured to compensate for hearing loss in the user of the hearing aid. The gain requested by the compressor at a given time and at a given frequency thus depends on the user's hearing threshold (and level of discomfort) at that frequency, the level of the input signal (at that frequency), and possibly the type of hearing aid involved.

[0034] The hearing device may include a compressor that provides a currently requested gain, applied to one or a weighted combination of the electrical input signals based on A) a level estimate of the electrical input signals in question and B) the user's needs, wherein a spatial filter controller is configured to apply first and / or second different sets of beamformer weights to the plurality of electrical input signals according to the currently requested gain. The spatial filter controller may be configured to apply a first set of beamformer weights to the plurality of electrical input signals when the currently requested gain is higher than a threshold gain. An appropriate (e.g., frequency-varying, predetermined, or adaptively determined) threshold gain may be stored in the hearing device's memory (or accessible by the hearing device).

[0035] In one embodiment, the hearing device is configured to adaptively determine (or select) an appropriate set of beamformer weights based on a currently requested gain provided by the compressor of the hearing device. The spatial filter controller may be configured to adaptively select an appropriate (e.g., predetermined) set of beamformer weights based on the requested gain from the compressor (e.g., among two or more sets of beamformer weights stored in memory). The spatial filter controller may be configured to adaptively select among two or more sets of beamformer weights (including first and second sets of beamformer weights), see, for example, [link to relevant documentation]. Figure 3 .

[0036] The hearing device may include a level detector configured to provide an estimate of the background noise level at a given time point. When the input level from the external sound field is sufficiently high (e.g., >70 dB SPL) and the background noise is sufficiently high, spatial filtering of the external sound field can be activated, and at these high input levels, the compression will reduce gain, and the spatial anti-feedback system can be disabled. The spatial filter controller may be configured to apply a second set of beamformer weights to the plurality of electrical input signals when the current background noise level is above a noise threshold level and the input level is above an input threshold level. An appropriate (e.g., frequency-varying, predetermined, or adaptively determined) noise threshold level may be stored in the hearing device's memory (or accessible by the hearing device), for example, along with corresponding values ​​of the input threshold levels (e.g., for each input converter).

[0037] Hearing devices may consist of or include hearing aids, headphones, headsets, ear protection devices, or combinations thereof.

[0038] In embodiments, the hearing device is adapted to provide frequency-varying gain and / or level-varying compression and / or frequency shifting (with or without frequency compression) from one or more frequency ranges to one or more other frequency ranges to compensate for a user's hearing impairment. In embodiments, the hearing device includes a signal processor for amplifying the input signal and providing a processed output signal.

[0039] The hearing device includes an output unit for providing stimulation, perceived as an acoustic signal by a user, based on processed electrical signals. In one embodiment, the output unit includes an output transducer. In another embodiment, the output transducer includes a receiver (speaker) for providing the stimulation as an acoustic signal to the user. In yet another embodiment, the output transducer includes a vibrator for providing the stimulation as mechanical vibrations of the skull to the user (e.g., in a bone-attached or bone-anchored hearing device).

[0040] The hearing device includes an input unit for providing an electrical input signal representing sound. In one embodiment, the input unit includes an input transducer, such as a microphone, for converting input sound into an electrical input signal. In another embodiment, the input unit includes a wireless receiver for receiving a wireless signal including sound and providing an electrical input signal representing said sound.

[0041] Hearing devices include directional microphone systems adapted to spatially filter sound from the environment, thereby enhancing a target sound source among multiple sound sources in the local environment of the user wearing the hearing device. In embodiments, the directional system is adapted to detect (e.g., adaptively detect) the direction from which a specific portion of the microphone signal originates. This can be achieved, for example, in a variety of different ways described in the prior art. In hearing devices, microphone array beamformers are commonly used to spatially attenuate background noise sources. Many beamformer variations can be found in the literature. Minimum variance distortionless response (MVDR) beamformers are widely used in microphone array signal processing. Ideally, an MVDR beamformer keeps the signal from the target direction (also known as the line of sight) unchanged while attenuating sound signals from other directions to the greatest extent possible. A generalized sidelobe canceller (GSC) structure is an equivalent representation of an MVDR beamformer, offering computational and digital representation advantages over a direct implementation of the original form.

[0042] In an embodiment, the hearing device includes an antenna and transceiver circuitry (such as a wireless receiver) for receiving direct electrical input signals from another device, such as an entertainment device (e.g., a television), a communication device, a wireless microphone, or another hearing device. In an embodiment, the direct electrical input signals represent or include audio signals and / or control signals and / or information signals.

[0043] In an embodiment, communication between the hearing device and another device is in baseband (audio frequency range, e.g., between 0 and 20 kHz). Preferably, the communication between the hearing device and the other device is based on some type of modulation at a frequency higher than 100 kHz. Preferably, the frequency used to establish a communication link between the hearing device and the other device is below 70 GHz, for example, in the range from 50 MHz to 70 GHz, for example, above 300 MHz, for example, in the ISM range above 300 MHz, for example, in the 900 MHz range, or in the 2.4 GHz range, or in the 5.8 GHz range, or in the 60 GHz range (ISM = Industrial, Scientific and Medical, such standardized ranges are defined, for example, by the International Telecommunication Union ITU). In an embodiment, the wireless link is based on standardized or proprietary technology. In an embodiment, the wireless link is based on Bluetooth technology (such as Bluetooth Low Energy technology).

[0044] In this embodiment, the hearing device is a portable device, such as a device that includes a local power source, such as a battery, for example a rechargeable battery.

[0045] In embodiments, the hearing device includes a forward or signal path between an input unit (such as an input converter, e.g., a microphone or microphone system and / or a direct electrical input (such as a wireless receiver)) and an output unit such as an output converter. In embodiments, a signal processor is located in the forward path. In embodiments, the signal processor is adapted to provide frequency-varying gain according to the specific needs of the user. In embodiments, the hearing device includes an analysis path having functionalities for analyzing the input signal (e.g., determining level, modulation, signal type, acoustic feedback estimate, etc.). In embodiments, some or all of the signal processing of the analysis path and / or signal path is performed in the frequency domain. In embodiments, some or all of the signal processing of the analysis path and / or signal path is performed in the time domain.

[0046] In this embodiment, the analog electrical signal representing the sound signal is converted into a digital audio signal during analog-to-digital (AD) conversion, wherein the analog signal is sampled at a predetermined sampling frequency or sampling rate f. s Perform sampling, f s For example, in the range from 8kHz to 48kHz (to suit specific application needs) at discrete time points t n (or n) provides digital samples x n (or x[n]), each audio sample passes through a predetermined N b Bit represents the acoustic signal at t n The value of N at time b For example, in a range from 1 to 48 bits, such as 24 bits. Each audio sample therefore uses N. b Bit quantization (resulting in 2^n voltammetry of audio samples) Nb (Number of different possible values). The numerical sample x has 1 / f s The duration of time, such as 50 μs, for f s =20kHz. In this embodiment, multiple audio samples are arranged in time frames. In this embodiment, a time frame includes 64 or 128 audio data samples. Other frame lengths may be used depending on the application.

[0047] In one embodiment, the hearing device includes an analog-to-digital (AD) converter to digitize an analog input (e.g., from an input converter such as a microphone) at a predetermined sampling rate, such as 20 kHz. In another embodiment, the hearing device includes a digital-to-analog (DA) converter to convert the digital signal into an analog output signal, for example, for presentation to the user via an output converter.

[0048] In embodiments, hearing devices such as microphone units and / or transceiver units include a TF-T converter unit for providing a time-frequency representation of the input signal. In embodiments, the time-frequency representation includes an array or mapping of corresponding complex or real values ​​of the signal in question over a specific time and frequency range. In embodiments, the TF-T converter unit includes a filter bank for filtering the (time-varying) input signal and providing multiple (time-varying) output signals, each output signal comprising a distinctly different frequency range of the input signal. In embodiments, the TF-T converter unit includes a Fourier transform unit for converting the time-varying input signal into a (time-)frequency signal. In embodiments, the hearing device considers a frequency range from the minimum frequency f... min up to the maximum frequency f max The frequency range includes a portion of the typical human hearing range from 20Hz to 20kHz, such as a portion of the range from 20Hz to 12kHz. Typically, the sampling rate f... s Greater than or equal to the maximum frequency f max twice that, i.e., f s ≥2f max In an embodiment, the signals of the forward and / or analytical pathways of the hearing aid are split into NI (e.g., uniformly wide) frequency bands, where NI is, for example, greater than 5, greater than 10, greater than 50, greater than 100, or greater than 500, and at least a portion thereof is processed individually. In an embodiment, the hearing aid is adapted to process the signals of the forward and / or analytical pathways (NP≤NI) on NP different channels. The channels may have consistent or inconsistent widths (e.g., width increases with frequency), overlap or non-overlap.

[0049] In an embodiment, the hearing device includes multiple detectors configured to provide status signals relating to the hearing device's current network environment (e.g., current acoustic environment), and / or the current state of the user wearing the hearing device, and / or the current state or operating mode of the hearing device. Alternatively or additionally, one or more detectors may form part of an external device that communicates with the hearing device (e.g., wirelessly). The external device may include, for example, another hearing device, a remote control, an audio transmission device, a telephone (e.g., a smartphone), external sensors, etc.

[0050] In one embodiment, one or more of the multiple detectors operate on the full-band signal (time domain). In another embodiment, one or more of the multiple detectors operate on the band-segmented signal ((time-)frequency domain), for example, in a limited number of frequency bands.

[0051] In one embodiment, multiple detectors include level detectors for estimating the current level of the signal in the forward path. In another embodiment, a predetermined criterion includes whether the current level of the signal in the forward path is higher or lower than a given (L-) threshold. In one embodiment, the level detector operates on a full-band signal (time domain). In another embodiment, the level detector operates on a band-split signal ((time-)frequency domain).

[0052] In a particular embodiment, the hearing device includes a voice detector (VD) for estimating whether (or with what probability) the input signal (at a specific point in time) includes a voice signal. In this specification, a voice signal includes speech signals from humans. It may also include other forms of vocalization produced by the human speech system (such as singing). In embodiments, the voice detector unit is adapted to classify the user's current acoustic environment as a "voice" or "no-voice" environment. This has the advantage that time periods including electrophonic signals of human vocalizations (such as speech) in the user's environment can be identified and thus separated from time periods that include only (or primarily) other sound sources (such as artificially generated noise). In embodiments, the voice detector is adapted to also detect the user's own voice as "voice." Alternatively, the voice detector is adapted to exclude the user's own voice from the detection of "voice."

[0053] In one embodiment, the hearing device includes a self-voice detector for estimating whether (or with what probability) a particular input sound (such as speech) originates from the voice of a system user. In another embodiment, the microphone system of the hearing device is adapted to distinguish between the user's own voice and the voice of another person, and possibly from voiceless sounds.

[0054] In one embodiment, the multiple detectors include motion detectors, such as accelerometers, accelerometers, and / or gyroscopes. In another embodiment, the motion detectors are configured to detect movement and / or orientation of the user or the user's head (e.g., including a hearing device) and provide detector signals indicating that movement.

[0055] In an embodiment, the hearing device includes a classification unit configured to classify the current situation based on input signals from (at least partially) a detector and possibly other inputs. In this specification, "current situation" is defined by one or more of the following:

[0056] a) Physical environment (including the current electromagnetic environment, such as the presence of electromagnetic signals (including audio and / or control signals) that are planned or unplanned to be received by the hearing device, or other properties of the current environment that are different from acoustics);

[0057] b) Current acoustic conditions (input level, feedback, etc.);

[0058] c) The user's current mode or state (movement, temperature, cognitive load, etc.);

[0059] d) The current mode or state of the hearing device and / or another device communicating with the hearing device (selected program, time elapsed since the last user interaction, etc.).

[0060] In embodiments, the hearing device includes an acoustic (and / or mechanical) feedback suppression system. Acoustic feedback occurs when the output speaker signal from an audio system that amplifies the signal picked up by the microphone returns to the microphone via an acoustic coupling portion through air or other media. This portion of the speaker signal returning to the microphone is then amplified again by the audio system before it reappears at the speaker and returns to the microphone again. As this cycle continues, the acoustic feedback effect becomes audible, such as unnatural signals or even worse, howling, when the audio system becomes unstable. This problem typically occurs when the microphone and speaker are placed close together, such as in hearing aids or other audio systems. Some other typical scenarios with feedback problems include telephone systems, broadcast systems, headsets, audio conferencing systems, etc. Adaptive feedback cancellation is capable of tracking changes in the feedback path over time. It estimates the feedback path based on a linear time-invariant filter, but its filter weights are updated over time. The filter update can be computed using stochastic gradient algorithms, including some form of least mean square (LMS) or normalized LMS (NLMS) algorithms. They all have the property of minimizing the mean square of the error signal, and NLMS further normalizes the filter update with respect to the square of the Euclidean norm of some reference signal.

[0061] In an embodiment, the feedback suppression system includes a feedback estimator for providing a feedback signal representing an estimate of the acoustic feedback path, and a combination unit, such as a subtraction unit, for subtracting the feedback signal from a signal in the forward path (e.g., picked up by an input transducer of the hearing device).

[0062] In embodiments, the hearing device also includes other suitable functions for the applications involved, such as compression, noise reduction, etc.

[0063] In embodiments, hearing devices include hearing aids, hearing instruments such as hearing devices adapted to be located at the user's ear or wholly or partially in the ear canal, such as headphones, headsets, ear protection devices, or combinations thereof. In embodiments, hearing aid systems include loudspeaker amplifiers (comprising multiple input converters and multiple output converters, for example, for use in audio conferencing scenarios), and may include spatial filters, and may provide multiple beamforming capabilities.

[0064] application

[0065] On the one hand, applications of the hearing device described in detail in the "Detailed Description" section and defined in the claims are provided. In embodiments, applications are provided in systems including audio distribution, such as systems including microphones and speakers sufficiently close to each other to cause feedback from the speakers to the microphones during user operation. In embodiments, applications are provided in systems including one or more hearing aids (hearing instruments), headphones, headsets, active ear protection systems, etc., such as in hands-free telephone systems, teleconferencing systems (e.g., including loudspeaker amplifiers), broadcasting systems, karaoke systems, classroom amplification systems, etc.

[0066] method

[0067] This application further provides a method for operating a hearing device, such as a hearing aid, configured to be located at or in the user's ear. The method includes:

[0068] - Provides multiple electrical input signals representing sound in the user's environment;

[0069] - Provide stimulation that can be perceived as sound by the user based on the electrical input signal or its processed version;

[0070] -Signals that provide spatial filtering based on the plurality of electrical input signals and configurable beamformer weights.

[0071] The method further includes:

[0072] - Apply a first and / or second set of beamformer weights to the plurality of electrical input signals, wherein the first set of beamformer weights is configured to provide spatial filtering of the sound from the output converter, and wherein the second set of beamformer weights is configured to provide spatial filtering of the external sound field.

[0073] When appropriately replaced by a corresponding process, some or all of the structural features of the apparatus described above, in detail in the "Detailed Description," or as defined in the claims can be combined with the implementation of the method of the present invention, and vice versa. The implementation of the method has the same advantages as the corresponding apparatus.

[0074] Computer-readable media

[0075] The present invention further provides a tangible computer-readable medium storing a computer program including program code, which, when the computer program is run on a data processing system, causes the data processing system to perform at least some (such as most or all) of the steps of the methods described above, in detail in the "Detailed Description" section, and as defined in the claims.

[0076] By way of example, but not limitation, the aforementioned tangible computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to execute or store required program code in the form of instructions or data structures and is accessible by a computer. As used herein, disks include compact discs (CDs), laser discs, optical discs, digital multipurpose discs (DVDs), floppy disks, and Blu-ray discs, wherein these disks typically magnetically copy data while simultaneously being optically copied using lasers. Combinations of the aforementioned disks should also be included within the scope of computer-readable media. In addition to being stored on tangible media, computer programs may also be transmitted via transmission media such as wired or wireless links or networks such as the Internet and loaded into data processing systems to run at locations other than tangible media.

[0077] Computer program

[0078] In addition, this application provides a computer program (product) including instructions that, when run by a computer, cause the computer to perform the steps of the methods (methods) described above, in detail in the "Detailed Description" section, and as defined in the claims.

[0079] Data processing system

[0080] In one aspect, the present invention further provides a data processing system, including a processor and program code, the program code causing the processor to perform at least some (such as most or all) of the steps of the methods described above, in detail in the "Detailed Description" section, and as defined in the claims.

[0081] Hearing system

[0082] On the other hand, the hearing system includes the hearing device described above, described in detail in the "Detailed Description" section, and defined in the claims, and also provides auxiliary devices.

[0083] In an embodiment, the hearing system is adapted to establish a communication link between the hearing device and the assistive device so that information (such as control and status signals, possibly audio signals) can be exchanged or forwarded from one device to another.

[0084] In one embodiment, the hearing system includes assistive devices such as a remote control, a smartphone, or other portable or wearable electronic devices such as a smartwatch.

[0085] In one embodiment, the assistive device is or includes a remote control for controlling the functions and operation of the hearing device. In another embodiment, the remote control functionality is implemented in a smartphone, which may run an app that enables control of the audio processing device via the smartphone (the hearing device includes a suitable wireless interface to the smartphone, such as Bluetooth or some other standardized or proprietary solution).

[0086] In an embodiment, the auxiliary device is or includes an audio gateway device adapted to receive multiple audio signals (e.g., from an entertainment device such as a TV or music player, from a telephone device such as a mobile phone, or from a computer such as a PC) and to select and / or combine appropriate signals (or combinations of signals) from the received audio signals for transmission to the hearing device.

[0087] In one embodiment, the assistive device is or includes another hearing device. In another embodiment, the hearing system includes two hearing devices adapted to implement a binaural hearing system such as a binaural hearing aid system.

[0088] APP

[0089] On the other hand, the present invention also provides a non-transitory application called an APP. An APP includes executable instructions configured to run on an assistive device to implement a user interface for the hearing device or hearing system described above, in detail in the "Detailed Description," and as defined in the claims. In an embodiment, the APP is configured to run on a mobile phone, such as a smartphone, or another portable device enabled to communicate with said hearing device or hearing system.

[0090] definition

[0091] The "near field" of a sound source is the region close to the source where sound pressure and sound particle velocity are out of phase (wavefronts are not parallel). In the near field, sound intensity can vary greatly with distance (compared to the far field). The near field is typically limited to a distance from the sound source equal to approximately one or two wavelengths of sound. The wavelength λ of sound is given by λ = c / f, where c is the speed of sound in air (343 m / s, @20℃) and f is the frequency. At f = 1 kHz, for example, the wavelength of sound is 0.343 m (i.e., 34 cm). On the other hand, in the acoustic "far field," wavefronts are parallel, and the sound field intensity decreases by 6 dB for every doubling of the distance from the sound source (inverse square law).

[0092] In this specification, "hearing device" refers to a device suitable for improving, enhancing, and / or protecting a user's hearing ability, such as a hearing aid, a hearing instrument, an active ear protection device, or other audio processing device, which achieves this by receiving sound signals from the user's environment, generating corresponding audio signals, possibly modifying the audio signals, and providing the possibly modified audio signals as audible signals to at least one ear of the user. "Hearing device" also refers to a device suitable for electronically receiving audio signals, possibly modifying the audio signals, and providing the possibly modified audio signals as audible signals to at least one ear of the user, such as headphones or headsets. The audible signals may be provided, for example, as sound signals radiating into the user's outer ear, sound signals transmitted as mechanical vibrations through the bone structures of the user's head and / or through parts of the middle ear to the user's inner ear, and electrical signals transmitted directly or indirectly to the user's cochlear nerve.

[0093] Hearing devices can be configured to be worn in any known manner, such as as a unit worn behind the ear (having a tube that directs radiated sound signals into the ear canal or having an output transducer, such as a loudspeaker, arranged close to or within the ear canal), as a unit wholly or partially arranged in the auricle and / or ear canal, as a unit connected to a fixed structure implanted in the skull, such as a vibrator, or as a connectable unit that is wholly or partially implanted. Hearing devices may include a single unit or several units that are electronically in communication with each other. The loudspeaker may be housed within a housing along with other components of the hearing device, or it may be an external unit (possibly combined with a flexible guiding element, such as a dome-shaped element).

[0094] More generally, a hearing device includes an input transducer for receiving acoustic signals from the user's environment and providing a corresponding input audio signal, and / or a receiver for receiving the input audio signal electronically (i.e., wired or wirelessly); a (typically configurable) signal processing circuitry (such as a signal processor, for example including a configurable (programmable) processor, such as a digital signal processor) for processing the input audio signal; and an output unit for providing an audible signal to the user based on the processed audio signal. The signal processor may be adapted to process the input signal in the time domain or in multiple frequency bands. In some hearing devices, amplifiers and / or compressors may constitute the signal processing circuitry. The signal processing circuitry typically includes one or more (integrated or separate) storage elements for executing programs and / or for storing parameters used (or potentially used) in the processing and / or for storing information suitable for the function of the hearing device and / or for storing information used, for example, in conjunction with an interface to the user and / or to a programming device (such as processed information, for example, provided by the signal processing circuitry). In some hearing devices, the output unit may include an output transducer, such as a loudspeaker for providing acoustic signals transmitted through space or a vibrator for providing acoustic signals propagating through structures or fluids. In some hearing devices, the output unit may include one or more output electrodes for providing electrical signals (e.g., a multi-electrode array for electrically stimulating the cochlear nerve). In embodiments, the hearing device includes a loudspeaker amplifier (including multiple input converters and multiple output converters, for example, in audio conferencing scenarios).

[0095] In some hearing devices, the vibrator may be adapted to transmit structurally propagated sound signals to the skull transcutaneously or through the skin. In some hearing devices, the vibrator may be implanted in the middle ear and / or inner ear. In some hearing devices, the vibrator may be adapted to provide structurally propagated sound signals to the middle ear bones and / or cochlea. In some hearing devices, the vibrator may be adapted to provide fluid-propagated sound signals to the cochlear fluid, for example, through the oval window. In some hearing devices, the output electrode may be implanted in the cochlea or on the medial side of the skull and may be adapted to provide electrical signals to the hair cells of the cochlea, one or more auditory nerves, the auditory brainstem, the auditory midbrain, the auditory cortex, and / or other parts of the cerebral cortex.

[0096] Hearing devices, such as hearing aids, can be adapted to the specific needs of users, such as those with hearing loss. The configurable signal processing circuitry of a hearing device can be adapted to apply frequency- and level-variable compression and amplification of the input signal. Customized frequency- and level-variable gain (amplification or compression) can be determined during the fitting process by the fitting system based on the user's hearing data, such as an audiogram, using basic fitting principles (e.g., speech adaptation). This frequency- and level-variable gain can be reflected, for example, in processing parameters, uploaded to the hearing device via an interface to a programming device (fitting system), and used by a processing algorithm executed by the hearing device's configurable signal processing circuitry.

[0097] A “hearing system” refers to a system that includes one or two hearing devices. A “binaural hearing system” refers to a system that includes two hearing devices adapted to work together to provide audible signals to both of a user’s ears. A hearing system or a binaural hearing system may also include one or more “assistive devices” that communicate with the hearing devices and influence and / or benefit from the functionality of the hearing devices. An assistive device may be, for example, a remote control, an audio gateway device, a mobile phone (such as a smartphone), or a music player. Hearing devices, hearing systems, or binaural hearing systems may be used, for example, to compensate for hearing loss in individuals with hearing impairment, enhance or protect the hearing ability of individuals with normal hearing, and / or transmit electronic audio signals to a person. Hearing devices or hearing systems may, for example, be part of or interact with broadcasting systems, active ear protection systems, hands-free telephone systems, car audio systems, entertainment (such as karaoke) systems, teleconferencing systems, classroom amplification systems, etc.

[0098] The present invention can be used, for example, in applications such as hearing aids. Attached Figure Description

[0099] Various aspects of the invention will be best understood from the following detailed description taken in conjunction with the accompanying drawings. For clarity, these drawings are schematic and simplified, showing only the details necessary for understanding the invention while omitting other details. Throughout the specification, the same reference numerals are used for the same or corresponding parts. Features of each aspect may be combined with any or all features of other aspects. These and other aspects, features, and / or technical effects will be apparent from and illustrated in the following figures, wherein:

[0100] Figure 1A A first embodiment of a hearing device according to the present invention, comprising a directional system including a plurality of input transducers, is shown.

[0101] Figure 1B A second embodiment (partially in the frequency domain) of a hearing device according to the invention, comprising a directional system, is shown, the directional system comprising two microphones.

[0102] Figure 2A A third embodiment of the hearing device according to the invention, comprising a directional system with two microphones, is shown, wherein the compressor controls the gain of the system using the input level from the microphones.

[0103] Figure 2B A fourth embodiment of the hearing device according to the invention is shown, comprising a directional system with two microphones, wherein a compressor controls the gain of the system (partially in the frequency domain) using input levels from the microphones.

[0104] Figure 3A fifth embodiment of the hearing device according to the invention, comprising a directional system with two microphones, is illustrated schematically, wherein the hearing device further comprises a feedback estimation and cancellation system.

[0105] Figure 4 Typical level compression curves are shown, characterized by providing relatively high gain at relatively low input levels and lower gain at higher input levels.

[0106] Figure 5 An example of a hearing device is shown, which includes a level-controlled spatial filter controller for a weighted combination based on the input signal and a compressor for the hearing device gain unit.

[0107] Figure 6A A first embodiment of a hearing device is shown, comprising three microphones located in an ITE portion adapted to be located at or within the user's ear canal.

[0108] Figure 6B A second embodiment of a hearing device is shown, comprising three microphones located in an ITE portion adapted to be located at or within the user's ear canal.

[0109] Figure 6C An embodiment of a hearing device is shown, comprising two microphones located in an ITE portion adapted to be located at or within the user's ear canal.

[0110] Figure 7A A first exemplary telephone mode usage scenario of the hearing device according to the present invention is shown.

[0111] Figure 7B A second exemplary telephone mode usage scenario of the hearing device according to the present invention is shown.

[0112] Figure 8 An embodiment of a self-voice beamformer is shown, for example, for use with Figure 7A , 7B The telephone mode shown.

[0113] The further applicability of the invention will become apparent from the detailed description given below. However, it should be understood that while the detailed description and specific examples illustrate preferred embodiments of the invention, they are given for illustrative purposes only. Other embodiments of the invention will become apparent to those skilled in the art based on the following detailed description. Detailed Implementation

[0114] The detailed description below, taken in conjunction with the accompanying drawings, serves as a description of various different configurations. This detailed description includes specific details to provide a thorough understanding of several different concepts. However, it will be apparent to those skilled in the art that these concepts can be implemented without these specific details. Several aspects of the apparatus and method are described by various different blocks, functional units, modules, elements, circuits, steps, processes, algorithms, etc. (collectively, “elements”). Depending on the specific application, design constraints, or other reasons, these elements may be implemented using electronic hardware, computer programs, or any combination thereof.

[0115] Electronic hardware may include microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), gating logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described in this specification. The term "computer program" should be interpreted broadly as instruction, instruction set, code, code segment, program code, program, subroutine, software module, application, software application, software package, routine, subroutine, object, executable, thread of execution, program, function, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or other names.

[0116] This application discloses a spatial feedback system that eliminates or attenuates acoustic feedback from vents or acoustic leakage between the earmold and the ear canal wall. Spatial anti-feedback is achieved using two microphones already present in conventional directional ITE-type HI. The conventional use of two microphones is to spatially filter external sounds from the environment to separate acoustic noise from the desired acoustic signal, which typically comes from the front direction. In this invention, this spatial filtering is also used to attenuate feedback or leakage from vents without attenuating the desired external acoustic signal. This is referred to herein as spatial anti-feedback.

[0117] Figure 1AAn embodiment of a hearing device including a directional system according to the present invention is shown. The hearing device HD, such as a hearing aid, is configured to be located at or within the user's ear, for example, wholly or partially within the user's ear canal. The hearing device includes an input unit comprising a plurality of input converters (M1, ..., MN) for providing corresponding electrical input signals (IN1, IN2, ..., INN) representing sounds in the user's environment. The hearing device also includes an output unit comprising an output converter SP, in this case a loudspeaker, for providing a stimulus that the user can perceive as sound based on the electrical input signals or a processed version thereof. The hearing device also includes spatial filters (w1, w2, ..., wN, CU) connected to the input and output units, configured to provide a spatially filtered signal OUT based on the plurality of electrical input signals and configurable beamformer weights (w1p, w2p, ..., wNp, where p is the beamformer weight recombination index). The spatial filter includes weighting units (w1, w2, ..., wN), such as multiplication units, each weighting unit being adapted to apply the corresponding beamformer weights (w1p, w2p, ..., wNp) to the corresponding electrical input signal (IN1, IN2, ..., INN) and provide the corresponding weighted input signal (Y1, Y2, ..., YN). N The spatial filter also includes a combining unit CU, such as a summing unit, for combining the weighted input signals into one or more spatially filtered signals, in this case, one (signal OUT), which is fed to the output converter SP (possibly further processed prior to this). The hearing device HD also includes a spatial filter controller SCU configured to apply (at least) a first and / or second set (p = 1, 2) of beamformer weights (w1p, w2p, ..., wNp) to the plurality of electrical input signals (IN1, IN2, ..., INN). The first set of beamformer weights (p = 1) is used to provide spatial filtering of the sound from the output converter SP (leaking back to the input converters, see the dashed arrows indicating the feedback paths h1, h2, ..., hN from the output converter SP to each of the N input converters (M1, M2, ..., MN) respectively). The second set of beamformer weights (p = 2) is used to provide spatial filtering of the external sound field (e.g., from a sound source located in the acoustic far field relative to the hearing device, see Figure 6A , 6B Spatial filtering (6C). The hearing device also includes a memory MEM accessible from the spatial filter controller SCU. The spatial filter controller is configured to adaptively select an appropriate set of beamformer weights (signal wip) from two or more sets (p = 1, 2, ...) of beamformer weights stored in the memory (including the first and second sets of beamformer weights). At a given point in time, the adaptive selection of the appropriate set of beamformer weights may, for example, depend on the current input level of one or more of a plurality of electrical input signals or the gain currently requested from the compressor and / or the currently estimated loop gain.

[0118] Figure 1B An embodiment of a hearing device including a directional system according to the present invention is shown. The input unit includes (e.g., only) two microphones (M1, M2) for converting sound from the environment into corresponding electrical input signals IN1, IN2. Figure 1B In this embodiment, the processing of the forward path (from sound input to sound output) of the hearing device is performed at least partially in the frequency domain. The input unit includes corresponding filter banks (FB-A1, FB-A2) configured to provide the electrical input signals (IN1, IN2) as digitized sub-band signals (X1, X2) in a time-frequency representation (k, m), where k and m are the frequency and time exponents, respectively. The sub-band electrical input signals (X1, X2) are fed to a spatial filter (weighting unit (w1, w2)) and a spatial filter controller SCU. Based on the input signals (X1, X2), such as their levels and / or SNR, the spatial filter controller SCU selects an appropriate set of beamformer filter weights (wip) from the memory MEM at a given time point and applies them to the corresponding weighting units (w1, w2), see signals w1p, w2p, thereby providing the corresponding weighted input signals Y1, Y2. The weighted input signals Y1, Y2 are added together by the SUM unit "+" to provide the spatially filtered (beamformed) signal Y. BF The hearing device also includes a synthesis filter bank FB-S, which converts the spatially filtered sub-band signal YBF into a spatially filtered time-domain signal OUT, which is then fed back to the loudspeaker SP to be converted into acoustic stimulation.

[0119] The spatial filter controller SCU is configured to apply different beamformer weights w1p and w2p to the two microphone channels for spatial anti-feedback or spatial filtering of the external sound field (e.g., a first set (p=1) of beamformer weights (w11, w21) is used for spatial filtering of the sound field from the speaker SP, and a second set (p=2) of beamformer weights (w12, w22) is used for spatial filtering of the external sound field from sound sources in the user's surrounding environment (not from the speaker of the hearing device).

[0120] Acoustic feedback can be highly unpredictable, especially when leakage is dominant. Therefore, it is advantageous to individually calibrate spatial anti-feedback for the user's ear. This can be achieved by using a conventional adaptive feedback path estimate to obtain an estimate of the feedback path (see, for example, [link to relevant documentation]). Figure 3Then, the difference in the estimated feedback path is used to generate a set of beamformer weights w1 and w2 to achieve spatial anti-feedback. Alternatively, the filter weights can also be obtained by designing to minimize the output of the directional unit (output = s1*w1 + s2*w2) while using an adaptive system that ensures the microphone input is dominated by the feedback signal. Alternatively, or additionally, the filter weights can be estimated from the online feedback path estimator.

[0121] One problem with using two microphones again is the difficulty in achieving spatial filtering of external sounds while simultaneously implementing spatial feedback immunity (when only two microphones are available). This invention proposes two methods to address this problem. First, it uses input levels to make the system adaptive; second, it allows the system to operate in separate frequency bands.

[0122] Traditional Hi-Fi systems use dynamic range compression (compressed amplification) to utilize the limited dynamic range of the user's hearing. This means that the gain in a Hi-Fi system is higher at low input levels and lower at higher input levels. By adapting spatial anti-feedback by using the input level (or a signal derived from the input level, such as the applied gain) to the system, spatial anti-feedback can be used at lower input levels where the gain of the hearing instrument is higher and therefore the separation problem is also higher. In situations with low input levels, spatial filtering of the external sound field is typically not required.

[0123] Figure 2A An embodiment of a hearing device according to the invention, comprising a directional system with two microphones, is shown, wherein a compressor controls the gain of the system using the input level from the microphones. Apart from the following distinctions, Figure 2A The embodiments are equivalent to Figure 1A Examples of implementations. Figure 2A The hearing aid embodiment includes only two input converters (microphones (M1, M2)), but additionally includes a compressor COMP, which includes a compression amplification algorithm for determining a (requested) gain that varies with the input level based on the user's needs (e.g., hearing loss) and the current input level. Based on this, a weight control signal Wctr is fed to the spatial filter controller SCU, which controls the currently selected set of beamformer weights wip, i = 1, 2, p = 1, 2 based on the current input levels of the electrical input signals IN1, IN2 for the requested gain (derived from the compression amplification algorithm adapted to the user's needs). The hearing aid HD also includes a processor HAG for further processing the spatially filtered signal Y. BF The processed signal OUT is provided and fed to the output converter SP. The compressor COMP is further configured to feed the gain control signal HAGctr to the processor HAG so that the processor can apply the relevant gain to the spatially filtered signal Y. BF (Based on the input level or the (requested) gain derived from it).

[0124] Figure 2B An embodiment of a hearing device according to the invention, comprising a directional system with two microphones, is shown, wherein a compressor controls the gain of the system (partially in the frequency domain) using input levels from the microphones. Apart from the following distinctions, Figure 2B The embodiments are equivalent to Figure 2A Examples of implementations. Figure 2B The hearing device embodiment includes appropriate analysis and synthesis filter banks (FB-A1, FB-A2, and FB-S, respectively) to enable processing of the forward path (and analysis sections (SCU, COMP, MEM)) in the frequency domain (each sub-band signal is processed separately). Figure 2B In the embodiment, the signal Y is used for further processing of spatial filtering. BF The processor HAG provides the processed signal Y G It is then fed to the synthesis filter bank FB-S to provide the processed time-domain output signal OUT, which is then fed to the loudspeaker SP.

[0125] The input level or compression level can be used as an input to the spatial filter controller (SCU) to switch between spatial anti-feedback (first) beamformer weights and conventional (second) directional beamformer weights.

[0126] When the input level from the external sound field is quite high (e.g., >70dB SPL) and the background noise is quite high, spatial filtering of the external sound field can be activated, and at these high input levels, compression will reduce gain, and the spatial anti-feedback system can be disabled.

[0127] The constraint on when spatial anti-feedback can be disabled is determined by the loop gain. Spatial anti-feedback can be disabled when the loop gain is low enough for the system to operate without spatial anti-feedback. Typically, this is when the loop gain (loop quantity value) is below 0 dB, but it can depend on how well other possible anti-feedback measures work in the HI (e.g., feedback cancellation systems, where the estimate of the feedback path is subtracted from the electrical input signal, see, for example). Figure 3 ).

[0128] The estimation of the feedback path from the output-to-input converter can be provided by several means, such as through... Figure 3 The corresponding adaptive filter is shown. The feedback estimate can be used in the spatial filter controller (SCU) to determine whether to apply the first or second set of beamformer weights at a given time point (see [reference]). Figure 3 The dashed arrows indicate that the feedback estimates EST1 and EST2 are fed to the combined space filter controller and compressor (SCU-COMP).

[0129] Figure 3 An embodiment of a hearing device according to the invention, comprising a directional system with two microphones, is illustrated schematically, wherein the hearing device further comprises a feedback estimation and cancellation system. Apart from the following distinctions, Figure 3 The embodiments are equivalent to Figure 2B An embodiment of the hearing device HD is described. The device also includes corresponding feedback cancellation systems for estimating and reducing feedback from the output converter (here, the loudspeaker SP) to the first and second input converters (here, microphones (M1, M2)). The first and second feedback cancellation systems include first and second feedback estimators (FBE1, FBE2) inserted into the respective microphone paths and subtraction units ('+') to subtract the corresponding estimates (EST1, EST2) of the feedback paths (h1, h2) from the input signals (IN1, IN2). The subtraction unit provides the corresponding feedback-corrected input signals (ER1, ER2), which are fed to the corresponding analysis filter banks (FB-A1, FB-A2) and the corresponding feedback estimators (FBE1, FBE2). Each of the feedback estimators (FBE1, FBE2) includes a corresponding algorithm part (ALG1, ALG2) implementing the corresponding adaptive filter and a variable filter part (FIL1, FIL2) (wherein the algorithm part (ALG1, ALG2) is configured to determine (and update) the filter coefficients of the variable filter part (FIL1, FIL2) via corresponding update numbers (UP1, UP2). The adaptive filter ((ALG1, FIL1), (ALG2, FIL2)) is, for example, an adaptive filter of the present technology. The algorithm part (ALG1, ALG2) may, for example, include a least mean square (LMS) or normalized LMS (NLMS) algorithm or a similar adaptive algorithm to estimate the filter coefficients (based on the reference signal OUT and the corresponding error signals (ER1, ER2)) so that when it is applied to the variable filter to filter the processed output (reference) signal OUT to provide the corresponding feedback estimates (EST1, EST2), the corresponding error signals (ER1, ER2) are minimized. Feedback estimates (EST1, EST2) can be fed to the spatial filter controller (SCU) (here, the combined SCU-COMP unit) to control the currently selected set of beamformer weights. Similarly, first and second algorithm control signals (A1ctr, A2ctr) can be generated in the combined spatial filter controller and compressor (SCU-COMP) and fed to the corresponding feedback estimators (FBE1, FBE2), for example, to control the adaptive rate of the adaptive algorithm and / or the update rate or update time of the filter coefficients in the variable filter (e.g., including disabling or enabling the aforementioned updates of the filter coefficients).

[0130] Figure 4Shows a typical level compression curve (gain G [dB] - input level L [dB SPL]), characterized by providing a relatively high gain (HG) at relatively low input levels (L < KP1) and a lower gain (LG) at higher input levels (L > KP2). The curve shows that at low input levels (e.g., L < L TH or < KP1), the spatial anti-feedback setting (first beamformer weights) of the directional system can be advantageously used (see "Spatial filtering of the feedback sound field"), and at higher (e.g., L > L TH or > KP2), the spatial filtering of external sounds (second beamformer weights) can be advantageously used (see "Spatial filtering of the external sound field"). In Figure 4 the exemplary embodiment, the threshold level L located between the first and second inflection points TH (KP1 < L TH < KP2) forms the boundary between using the first and second sets of beamformer weights. The threshold level L TH can be predetermined, for example, for the user's hearing situation (e.g., audiogram and / or level sensitivity). The threshold level L TH can be adaptively determined (see the double arrow denoted as "Adaptive" in Figure 4 ), for example, according to the current signal-to-noise ratio (SNR). The threshold level L TH can be adaptively determined, for example, according to the current signal-to-noise ratio (SNR) and the currently requested gain (or input level). The threshold level L TH can increase with an increase in SNR (e.g., within the minimum L TH,min and maximum L TH,max of the input level). For relatively low input levels (high gain), for input levels below the predetermined threshold level, the threshold level L TH can increase with an increase in SNR.

[0131] The spatial filter controller SCU is configured to apply the first and / or second different sets of beamformer weights to a plurality of electrical input signals according to the estimated input level (or the requested gain determined therefrom by the compression amplification algorithm). In an embodiment, the application of a given set of beamformer weights further depends on the current signal-to-noise ratio (SNR) of the electrical input signal or the signal derived therefrom.

[0132] For example, if the electrical input signal has a relatively high SNR and a relatively low gain (high level), no noise reduction is required (e.g., achieved by processing signals from the acoustic far field with the second beamformer weights), so the first beamformer weights (providing spatial feedback attenuation) can be advantageously applied.

[0133] To avoid fluctuations between the two types of orientation settings, hysteresis can be built into the decision. In an embodiment, for an increasing level, when L becomes greater than KP1 + ΔL1 (where ΔL1 ≤ (KP2 - KP1)), a switch from the first to the second beamformer weight occurs, and for a decreasing level, when L becomes less than KP2 - ΔL2 (where ΔL2 ≤ (KP2 - KP1)), a switch from the second to the first beamformer weight occurs. As an alternative, a gradual change between the two sets of beamformer weights can be introduced when the input level is between the two inflection points KP1 < L < KP2.

[0134] frequency band

[0135] The system described above can be designed to operate in separate frequency bands, meaning, for example, that the spatial anti-feedback is active only in the frequency bands where feedback is a problem (e.g., between 1 kHz and 8 kHz or between 1 kHz and 4 kHz). Additionally, the adaptive system described above can also be applied separately in frequency bands, meaning that the spatial anti-feedback turning into spatial filtering of the external sound field is active only in the frequency bands where compression has been targeted for a system without spatial anti-feedback or where the gain has been reduced sufficiently and / or spatial filtering of the external sound field is desired. In an embodiment, only one of the first and second sets of beamformer weights is applied at a given time in a given frequency band. In an embodiment, the first set of beamformer weights is applied in at least one frequency band while the second set of beamformer weights is applied in another frequency band.

[0136] Figure 5 An example of a hearing device is shown, which includes a spatial filter controller SCU for controlling based on the level of the resulting weighted combination (beamformed signal Y BF ) of the input signal and a compressor COMP of the hearing device gain unit HAG. Except for the differences described below, Figure 5 the hearing device embodiment is equivalent to Figure 2A the embodiment. Figure 5 The hearing device embodiment of BF includes a signal-to-noise ratio and level estimator (SNR and LD respectively) for providing estimates of the SNR and level of the incoming signal (here the spatially filtered (beamformed) signal Y Figure 2A ). Instead of analyzing the first and second electrical input signals (IN1, IN₂) (as in Figure 5 ), the compressor COMP of the BF embodiment receives the current estimate of the level of the beamformed signal Y BF . Further, the current SNR (signal snr) of the spatially filtered signal Y BFThe current estimate of the beamforming signal YBF level IL is provided together with the spatial filter controller SCU. The requested gain RG is determined by the compressor COMP based on the input level IL of the beamforming signal YBF (e.g., ...). Figure 4 As shown, for a given frequency band, individually (differently)... Based on this, the spatial filter controller (SCU) determines an appropriate set of beamformer weights (wip = w1p, w2p) (as shown in the diagram). Figure 4 (As discussed) and the control signal Wctr is used to read the set of beamformer weights from the memory unit MEM. The space filter controller SCU applies an appropriate set of beamformer weights (wip = w1p, w2p) to the space filter BFU.

[0137] exist Figure 5 In this embodiment, the level and SNR are based on the beamforming signal Y. BF Estimation is performed. One or two parameters (level and SNR) can be estimated in many different ways, for example, based on one or more electrical input signals (IN1, IN2).

[0138] In this embodiment, the voltage level and SNR are estimated directly from the electrical input signals (IN1, IN2). This can be advantageous because the voltage level and SNR may change as the beamformer changes.

[0139] Figure 6A An embodiment of a hearing device is shown, including an ITE portion (ITE) adapted to be located at or within the user's ear canal. The ITE portion may, for example, constitute a hearing device, or it may form part of a hearing device that also includes one or more portable portions, such as a BTE portion configured to be worn on or behind the ear (auricle) and connected to the ITE portion via acoustic, electrical, or electromagnetic (e.g., optical) connections during operation. The ITE portion may include a housing ( Figure 6A The shell (earmold) in the ear can be customized to fit the features (ear and / or ear canal) of a particular user or can be a standard piece planned for use by a group of customers ("one size fits all").

[0140] The ITE section includes ventilation channels (or multiple ventilation channels), in Figure 6A The vent is indicated by a single through-hole (vent). The vent channel can take different shapes, but it extends longitudinally through the cross-section of the housing portion of the ITE. Furthermore, it can be distributed across multiple separate vent channels, one or more of which can be formed as a through-hole or a recess in the housing surface (forming a channel with the wall (skin / tissue) of the ear canal), see [link to relevant documentation]. Figure 6A Skin-shell leakage channels (which can be intentional or unintentional).

[0141] The hearing device (here, the ITE section) includes three input converters (here, microphones M1, M2, M3, providing corresponding (e.g., digitized) electrical input signals (possibly provided as sub-band signals)), electrically connected to provide spatially filtered (beamforming) signals (e.g., to the processor HAG) to the processor HAG. Figure 5 Y in BF The spatial filter and controller (BF-CNT) are used to adjust the sound field based on the sound field S. ENV The acoustic environment is reflected by the electrical input signal picked up by the microphone, and appropriate gain is applied according to user needs to provide a processed signal (e.g., Figure 5 Y in G The processed signal is fed to the output converter (in this case, the speaker SP) and presented to the user as an audible signal (here, via a sound field S that generates air vibrations in the residual cavity between the shell of the ITE section and the eardrum in the ear canal). ED The spatial filter and controller (BF-CNT) is configured, as proposed in this invention, to apply an appropriate set of beamformer weights to three electrical input signals and provide corresponding spatially filtered signals. This set of beamformer weights is selected based on the input level and / or the requested gain (and thus the user's hearing condition) (possibly) and other properties of the input signals (such as the target signal-to-noise ratio).

[0142] Hearing devices may include fewer than three or more input transducers (e.g., microphones). Some microphones may be located in other parts of the hearing device (possibly in the cochlea or elsewhere in or around the user's ear (e.g., in a BTE portion adapted to be positioned in or behind the auricle)). In an embodiment, one of the microphones is located on or near the surface of the ITE portion facing the residual cavity and eardrum, for example, to measure or monitor the sound field in the residual cavity (e.g., for active noise cancellation, etc.).

[0143] Figure 6A The three microphones in the embodiment are shown located on or near the environmentally-facing portion of the ITE section (in contrast to the residual cavity and eardrum), for example, mounted on the panel of the earmold. In the embodiment, at least one microphone is positioned along the longitudinal axis of the hearing device in the direction toward the eardrum (to create a microphone axis toward the eardrum). This facilitates spatial separation of sound from the outside (environment) and from the inside (residual cavity), including spatial filtering of sound from the output converter (speaker SP). Such an embodiment in Figure 6B , 6C As shown in the image.

[0144] Figure 6B An embodiment of the hearing device according to the invention is shown, comprising three microphones located in an ITE portion adapted to be located at or within the user's ear canal. Figure 6BAn embodiment of the hearing device includes three microphones (M1, M2, M3) in the ITE section. Two of these microphones (M1, M2) face the environment, and one microphone (M3) faces the eardrum (when the hearing device is installed and in operation). The hearing device includes or is constituted by the ITE section. The ITE section may include a seal for providing a tight seal against the ear canal walls (see [link to documentation]). Figure 6B The "seal" in the middle) allows the microphone (M3) facing the eardrum to communicate with ambient sounds (S) impacting the ear canal (and hearing device). ITE Acoustic "isolation", see Figure 6B In one embodiment, the fitting is more open to allow ambient sound to reach the microphone (M3) facing the eardrum. The hearing device HD may include... Figure 1A , 1B The same functional elements as in embodiments 2A, 2B, 3, 5, 6A, and 7A.

[0145] Figure 6C An embodiment of a hearing device HD, such as a hearing aid, according to the present invention includes two microphones (M1, M2) located in an ITE portion. The ITE portion includes a housing, and the two ITE microphones are located, for example, longitudinally along the ear canal axis of the housing (see...). Figure 6C The midpoint line (arrow pointing "inward") is located therein, when the hearing device HD is mounted on or over the user's ear during operation. The ITE section also includes a guide ( Figure 6C The “guide” in the image is configured to guide the ITE portion in the ear canal during the installation and use of the hearing device HD, without completely blocking the ear canal (to avoid ear blockage and to allow the sound field S to pass through). ITE The ambient sound reaches the microphone (M2) closest to the eardrum. The ITE section also includes a speaker (facing the eardrum) for playing the resulting audio signal to the user, thereby creating a sound field in the residual cavity. A portion of this leaks back towards the ITE microphones (M1, M2) and the environment. The hearing device (e.g., the ITE section) constitutes a part customized for the user's ear, for example, in terms of shape, or alternatively, has a standardized shape. The hearing device HD may include... Figure 1A , 1B The same functional elements as in embodiments 2A, 2B, 3, 5, 6A, 7A, and 7B.

[0146] Figure 7A and 7B An exemplary telephone mode of the hearing device HD according to the present invention is shown. In this application, our objective is to spatially reduce feedback in both the locally presented beamformer signal and the beamformer signal presented to the remote speaker in the telephone conversation.

[0147] Figure 7AAn embodiment of a hearing device HD is shown, comprising two microphones (M1, M2) to provide electrical input signals IN1, IN2 representing the sound in the user's environment. The hearing device also includes a spatial filter DIR and a self-voice DIR, each spatial filter providing spatially filtered signals (ENV and OV, respectively) based on the electrical input signals. The spatial filter DIR may, for example, implement a first feedback cancellation and / or a second target holding, noise-canceling beamformer according to the invention. The spatial filter "self-voice DIR" is a spatial filter according to the invention. The spatial filter "self-voice DIR" implements the first feedback cancellation and / or the second self-voice beamformer (oriented towards the user's mouth) (its activation is, for example, controlled by a self-voice presence control signal and / or a telephone mode control signal and / or a remote speaker presence control signal). In specific telephone operation mode, the user's self-voice is picked up by microphones M1 and M2 and spatially filtered by the self-voice beamformer of the spatial filter "Self-Voice DIR" to provide a signal OV. This signal is fed to the transmitter Tx and transmitted (via a cable or wireless link to the telephone (see the dashed arrow labeled "To Telephone" and the telephone symbol)). In specific telephone operation mode, the signal PHIN is received from the telephone via the (wired or wireless) receiver Rx (as shown by the telephone symbol and the dashed arrow labeled "From Telephone"). When the remote speaker is active, the signal PHIN contains the speech from the remote speaker, for example, transmitted via the telephone line (e.g., entirely or partially wireless, but usually at least partially cable-based). The "remote" telephone signal PHIN is mixed with the ambient signal ENV from the spatial filter DIR in the combining unit '+' (here, the summing unit). The mixed signal OUT is fed to the output converter SP (such as a speaker or the vibrator of a bone conduction hearing device) to be presented to the user as sound.

[0148] In addition to Figure 7B The positive label indicates the feedback path outside of the self-voice beamformer during a telephone conversation (denoted as FB). FEOV (thick dashed line) Figure 7B and Figure 7A same.

[0149] At the self-voice beamformer (provided by the self-voice DIR unit), we have no feedback (similar to a closed loop), but we may have an echo problem, which is part of the external signal picked up by the self-voice beamformer and transmitted back to the far-end speaker. This is likely the case when the far-end speaker is active (see [link to documentation]). Figure 7B The circled number "1" indicates that, in this case, the distant speaker's voice is played through the speaker SP of the hearing device HD (see circled number "2"). This is achieved via feedback pathways FB1 and FB2 (in...). Figure 7BThe voice of the remote speaker (referred to as FB) is picked up by microphones (M1, M2) (see circled number "3"). The two electrical input signals are combined in the self-voice DIR unit (in normal self-voice operation mode) to form the self-voice signal OV (see circled number "4"). The self-voice signal OV may not contain the voice of the hearing device user, as he or she may be quiet when the remote speaker is active. On the other hand, the self-voice signal OV may contain a portion of the remote speaker's voice. In the latter case, the remote speaker's voice, after being transmitted (via transmitter Tx, for example via local telephone and PSTN) to the "other end," eventually reaches the remote speaker as an unwanted echo (again) (see circled number "5"). In this case, it is desirable to use a self-voice beamformer (when the hearing device user is speaking) suitable for canceling ambient noise and a feedback cancellation beamformer (when the remote user is speaking) (the remote echo is denoted as FB). FEOV The transition between the thick dashed lines and the circled numbers 1-5 (as shown in the illustration) is gradual.

[0150] The switching (gradation) between the first (feedback cancellation) beamformer and the second (self-voice, ambient noise reduction) beamformer (self-voice DIR) can, for example, be controlled by a voice detector capable of detecting the hearing device user's self-voice and a mode control signal indicating whether the hearing device is in telephone operation mode. If so, the switching (or gradation) of the self-voice DIR unit between the (second) self-voice beamformer and the (first) feedback cancellation beamformer can be based on whether the self-voice detector detects the hearing device user's self-voice (assuming the user and the remote speaker (typically) do not speak simultaneously). In an embodiment, the hearing device includes a separate voice detector connected to the receiver Rx to determine whether the signal from the remote end contains speech (or any other detector indicating the speech activity of the remote speaker). This voice detector can then (optionally) be used for switching between the two beamformers of the self-voice DIR unit (under the same assumption of not speaking simultaneously). The hearing device may include a self-voice detector (e.g., connected to one of the electrical input signals (IN1, IN2) or a self-voice signal OV) and a voice detector for detecting distant speech (e.g., connected to the receiver Rx or the combination unit '+', based on the output signal OUT), and the combined result of the two detectors controls the switching between the two beamformers.

[0151] Figure 8 An embodiment of a self-voice beamformer is shown, for example, for use with Figure 7A , 7B The telephone mode shown is implemented using a configuration that includes two microphones. Figure 8A self-voice beamformer according to the present invention is shown, illustrating how the gain of the self-voice enhanced post-filter (OV-PF) can be estimated. Figure 8 G in OV,1 (k) and G OV,2 (k)). The self-voice gain is determined based on the current noise estimate, which is here determined by the self-voice cancellation beamformer (C2(k)) and by the complex-valued beamformer weights (w) (which vary with frequency, see frequency exponent k). ov_cncl_1 (k),w ov_cncl_2 (k)) determined) and another beamformer (C1(k), here an omnidirectional beamformer, composed of complex-valued beamformer weights (w) containing the self-voice signal. ov1 (k),w ov2 (k)) Determined) combination is provided. In an embodiment, the self-voice enhancement beamformer is adaptive. When the hearing device is installed and in operation, the direction from the user's mouth is schematically shown (see Figure 8 (The solid arrow in the middle is labeled "self-voice"). Correspondingly, the direction from the external sound source is... Figure 8 The diagram schematically illustrates a (potentially adaptive) beamformer configuration, where the post-filter gain (PF gain) G OV,1 (k) and G OV,2 (k) is determined (see the output of the OV-PF module) and applied in the corresponding multiplication unit ('X') to the corresponding input signals X1(k) and X2(k). The resulting signals (G, respectively) OV,1 (k)X1(k) and G OV,2 (k)X2(k)) are summed in the summation unit ('+') to provide the self-voice estimate Y. OV (k). Self-voice estimation (Y) BF , Figure 7A , 7B The OV (online voice) can (e.g., in self-voice operation mode, such as when a connection to a telephone or other remote device is established) (see e.g., see Figure 7A , 7B ()) Via transmitter (see, for example, see) Figure 7A The Tx in 7B is transmitted to a remote device (e.g., to the remote listener of a telephone, see [link]). Figure 7A , 7B In "Self-voice mode", noise from external sound sources can be reduced by the beamformer.

[0152] A binaural hearing system may be provided, comprising first and second hearing devices (such as hearing aids) as described above. The first and second hearing devices may be configured to enable the exchange of data, such as audio data, with another device, such as a telephone or loudspeaker, or a computer (such as a PC or tablet). Self-voice estimation may be provided based on signals from microphones in the first and second hearing devices. Self-voice detection may be provided in both hearing devices. The final self-voice detection judgment may be based on self-voice detection values ​​from both hearing devices or on signals from microphones in the first and second hearing devices.

[0153] When appropriately replaced by a corresponding process, the structural features of the apparatus described above, in detail in the "Detailed Description" section, and as defined in the claims can be combined with the steps of the method of the present invention.

[0154] Unless explicitly stated otherwise, the singular forms “a” and “the” used herein include the plural forms (i.e., meaning “at least one”). It should be further understood that the terms “having,” “comprising,” and / or “including” as used in the specification indicate the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. It should be understood that, unless explicitly stated otherwise, when an element is referred to as “connected” or “coupled” to another element, it may be a direct connection or coupling to the other element, or there may be intermediate inserting elements. The term “and / or” as used herein includes any and all combinations of one or more of the listed related items. Unless explicitly stated otherwise, the steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed.

[0155] It should be understood that references to "an embodiment," "an embodiment," "an aspect," or "may" in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Furthermore, particular features, structures, or characteristics may be suitably combined in one or more embodiments of the invention. The foregoing description is provided to enable those skilled in the art to implement the various aspects described herein. Various modifications will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects.

[0156] The claims are not limited to the aspects shown herein, but encompass the full scope consistent with the language of the claims, wherein, unless expressly stated, an element referred to in the singular does not mean "one and only one," but rather "one or more." Unless expressly stated, the term "some" means one or more.

[0157] Therefore, the scope of this invention should be determined based on the claims.

[0158] References

[0159] ·EP3267697A1(Oticon)10.01.2018.

Claims

1. A hearing device configured to be located at or in a user's ear, the hearing device comprising: The input unit includes multiple input converters for providing corresponding electrical input signals representing sounds in the user's environment; The output unit includes an output transducer for providing a stimulus that can be perceived as sound by a user based on the electrical input signal or a processed version thereof; First and second spatial filters, each spatial filter being connected to the input unit and configured to provide corresponding first and second spatial filtered signals based on a plurality of electrical input signals and configurable beamformer weights; in The first spatial filter implements a feedback cancellation beamformer or a target-holding, noise-cancelling beamformer toward the user environment at a given time; The second spatial filter implements either a feedback cancellation beamformer or a self-voice beamformer toward the user's mouth at a given time. and The second spatial filter is controlled by a self-voice presence control signal, and / or a remote speaker presence control signal, and / or a telephone mode control signal; The hearing device is configured to operate in multiple modes, including a communication mode, which includes a telephone mode. The hearing device is configured such that, in the telephone mode, the second spatial filter is adapted to gradually change between A) and B): A) A self-voice beamformer suitable for picking up the user's voice while eliminating ambient noise during the user's speech; and B) Feedback cancellation beamformer when the hearing device user is not speaking.

2. The hearing device according to claim 1, configured to determine or select the beamformer weights according to the operating mode of the hearing device.

3. The hearing device according to claim 1, configured such that in the telephone mode, the user's self-voice is picked up by an input converter and spatially filtered by a self-voice beamformer to provide a second spatially filtered signal, the second spatially filtered signal being fed to the transmitter of the hearing device and transmitted to the telephone.

4. The hearing device according to claim 1, configured such that in the telephone mode, a signal is received from the telephone via the receiver of the hearing device.

5. The hearing device of claim 3, configured such that a signal from a telephone is mixed in a combining unit with a signal from a first spatial filter of the environment, the mixed signal being fed to the output converter to be presented to the user as sound.

6. The hearing device according to claim 1, configured such that in the telephone mode, the second spatial filter is adapted to gradually change between A) and B): A) A self-voice beamformer suitable for picking up the user's voice while eliminating ambient noise during the user's speech; and B) Feedback cancellation beamformer when the remote user speaks.

7. The hearing device of claim 1, configured such that in the telephone mode, the second spatial filter implements a feedback cancellation beamformer.

8. The hearing device according to claim 1, configured such that in the telephone mode, the second spatial filter is adapted to gradually change between A) and B): A) A self-voice beamformer suitable for picking up user voice while eliminating ambient noise, when the remote user is not speaking; and B) Feedback cancellation beamformer when the remote user speaks.

9. The hearing device according to claim 1, further comprising: Self-voice detectors are used to estimate whether, or with what probability, a given input sound originates from the voice of a system user.

10. The hearing device according to claim 1, further comprising: A mode indicator provides a mode control signal that indicates whether the hearing device is in telephone mode.

11. The hearing device according to claim 6, configured to control the gradation of the second spatial filter based on a self-voice presence control signal.

12. The hearing device according to claim 4, further comprising: A separate voice detector connected to the receiver determines whether the signal from the telephone contains voice.

13. The hearing device of claim 12, configured to control the gradation of the second spatial filter according to the separate speech detector.

14. The hearing device of claim 12, configured to control the gradation of a second spatial filter based on a self-voice detector and the separate voice detector.

15. The hearing device according to claim 1, comprising two input converters.

16. The hearing device of claim 1, wherein the output transducer is or includes a loudspeaker or a vibrator of a bone conduction hearing device.

17. The hearing device of claim 1, wherein the input unit comprises a corresponding filter bank configured to provide the electrical input signal in a time-frequency representation (k,m), wherein k and m are the frequency index and the time index, respectively.

18. The hearing device of claim 1, configured such that the beamformer weights vary with frequency.

19. The hearing device of claim 1, configured such that the beamformer weights are adaptively determined.

20. The hearing device of claim 1, wherein the hearing device is or includes a hearing aid, headphones, a headset, an ear protection device, or a combination thereof.

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