Binaural hearing device system with binaural active occlusion cancellation

Abstract

A binaural hearing system includes a first hearing device and a second hearing device, each of which comprising: an input transducer; a transducer audio signal processor configured to provide a processed input transducer audio signal; an ear canal microphone; an ear canal audio signal processor configured to provide a processed ear canal audio signal; a first signal combiner configured to combine the processed input transducer audio signal with the processed ear canal audio signal to obtain an output transducer audio signal; a signal level detector configured to determine a signal level of (1) the output transducer audio signal or (2) an audio signal included in formation of the output transducer audio signal; and an output transducer; wherein the binaural hearing system further comprises a binaural excessive level detector connected to the first hearing device's signal level detector and the second hearing device's signal level detector.

Claims

1. A binaural hearing system comprising a first hearing device and a second hearing device, each of which comprises: an input transducer for provision of an input transducer audio signal; a transducer audio signal processor configured to process the input transducer audio signal into a processed input transducer audio signal; an ear canal microphone for provision of an ear canal microphone audio signal based on sound received inside an ear canal of a user wearing the binaural hearing device; an ear canal audio signal processor configured to process the ear canal microphone audio signal into a processed ear canal audio signal; a first signal combiner configured to combine the processed input transducer audio signal with the processed ear canal audio signal to obtain an output transducer audio signal; a signal level detector configured to determine a signal level of (1) the output transducer audio signal or (2) an audio signal included in formation of the output transducer audio signal, wherein the signal level detector is configured to provide an output signal based on the determined signal level; and an output transducer configured to provide an acoustic sound signal for emission towards an eardrum of the user based on the output transducer audio signal; wherein the binaural hearing system further comprises a binaural excessive level detector connected to the signal level detector of the first hearing device and the signal level detector of the second hearing device, and wherein the binaural excessive level detector is configured to output (1) a first control signal for the ear canal audio signal processor of the first hearing device and (2) a second control signal for the ear canal audio signal processor of the second hearing device, based at least in part on the signal level determined by the signal level detector of the first hearing device and/or the signal level determined by the signal level detector of the second hearing device; and wherein the ear canal audio signal processor in the first hearing device is configured to attenuate the ear canal microphone audio signal in the first hearing device based on the first control signal, and/or the ear canal audio signal processor in the second hearing device is configured to attenuate the ear canal microphone audio signal in the second hearing device based on the second control signal.

2. The binaural hearing system according to claim 1, wherein the ear canal audio signal processor in each of the first and second hearing devices is configured to process the respective ear canal microphone audio signal based on the respective one of the first and second control signals of the binaural excessive level detector such that each of the processed ear canal audio signals is attenuated by a same amount.

3. The binaural hearing system according to claim 1, further comprising a wearable device that comprises the first and second hearing devices and the binaural excessive level detector.

4. The binaural hearing system according to claim 1, wherein the first hearing device comprises a first part of the binaural excessive level detector and the second hearing device comprises a second part of the binaural excessive level detector; wherein the first part of the binaural excessive level detector is connected to the signal level detector of the first hearing device and the signal level detector of the second hearing device, and is configured to output the first control signal to the ear canal audio signal processor of the first hearing device based on the determined signal levels; and wherein the second part of the binaural excessive level detector is connected to the signal level detector of the first hearing device and the signal level detector of the second hearing device, and is configured to output the second control signal to the ear canal audio signal processor of the second hearing device based on the determined signal levels.

5. The binaural hearing system according to claim 1, wherein the binaural excessive level detector is configured to detect excessive level by comparing each of the output signals of the signal level detectors with a predetermined threshold.

6. The binaural hearing system according to claim 5, wherein when at least one of the output signals exceeds the predetermined threshold, the ear canal audio signal processor of the first hearing device is configured to attenuate the processed ear canal audio signal of the first hearing device, and/or the ear canal audio signal processor of the second hearing device is configured to attenuate the processed ear canal audio signal of the second hearing device.

7. The binaural hearing system according to claim 1, wherein the ear canal audio signal processor in each of the first and second hearing devices is configured to cause that at least one of the processed ear canal audio signals to attenuate by an amount required to keep signals of the first hearing device and/or the second hearing device within a dynamic range of the first hearing device and/or the second hearing device.

8. The binaural hearing system according to claim 1, further comprising at least one body conducted sound detector that is configured to detect body conducted sound in the ear canal(s) of the user of the binaural hearing system.

9. The binaural hearing system according to claim 1, wherein the first hearing device comprises a first body conducted sound detector configured to detect body conducted sound in one of the ear canals of the user; and wherein the second hearing device comprises a second body conducted sound detector configured to detect body conducted sound in another one of the ear canals of the user.

10. The binaural hearing system according to claim 8, wherein the at least one body conducted sound detector is configured to provide a detector output to the binaural excessive level detector, the detector output indicating whether body conducted sound has been detected in the ear(s) of the user.

11. The binaural hearing system according to claim 10, wherein the binaural excessive level detector is configured to disable the combining of the processed input transducer audio signal with the processed ear canal audio signal in the first hearing device and/or the second hearing device, based on the detector output.

12. The binaural hearing system according to claim 8, wherein the at least one body conducted sound detector is configured to separate the body conducted sound from external sound using a blind source separation (BSS) algorithm.

13. The binaural hearing system according to claim 8, wherein the at least one body conducted sound detector comprises an acceleration sensor and/or a vibration sensor.

14. The binaural hearing system according to claim 8, wherein the at least one body conducted sound detector comprises a binaural impact sound detector that is configured to detect impact sound occurring simultaneously in both ears of the user.

15. The binaural hearing system according to claim 1, wherein each of the first and second hearing devices comprises an acoustic leakage detector configured to determine at least one transfer function.

16. The binaural hearing system according to claim 15, wherein the transfer function is associated with a path from an input of the output transducer to an output of the input transducer, from an input of the output transducer to an output of the ear canal microphone, or from the output of the input transducer to the input of the output transducer.

17. The binaural hearing system according to claim 1, wherein each of the first and second hearing devices comprises a filter configured to model a transfer function that is associated with a path from an input of the output transducer to an output of the ear canal microphone, wherein an output signal provided by the filter corresponds to a part of the ear canal audio signal originating from the output transducer.

18. The binaural hearing system according to claim 1, wherein the binaural excessive level detector is configured to determine an acoustic leakage in at least one of the ear canals.

19. The binaural hearing system according to claim 18, wherein the binaural excessive level detector is configured to cause a signal level reduction for at least one of the first and second hearing devices, the signal level reduction being inversely proportional to the determined acoustic leakage.

20. The binaural hearing system according to claim 18, configured to provide a balanced occlusion cancellation based on the determined acoustic leakage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other and further aspects and features will be evident from reading the following description of the embodiments.

(2) The drawings illustrate the design and utility of embodiments, in which similar elements are referred to by common reference numerals. These drawings are not necessarily drawn to scale. In order to better appreciate how the above-recited and other advantages and objects are obtained, a more particular description of the embodiments will be rendered, which are illustrated in the accompanying drawings. These drawings depict only typical embodiments and are not therefore to be considered limiting of its scope.

(3) In the drawings:

(4) FIG. 1 shows a block diagram of a known active occlusion cancellation circuit,

(5) FIG. 2 shows a block diagram of another known active occlusion cancellation circuit,

(6) FIG. 3 shows a block diagram of a binaural hearing device system with a new binaural active occlusion cancellation circuit,

(7) FIG. 4 shows a block diagram of another binaural hearing device system with a new binaural active occlusion cancellation circuit,

(8) FIG. 5 shows a block diagram of yet another binaural hearing device system with the new binaural active occlusion cancellation circuit, and

(9) FIG. 6 shows a block diagram of still yet another binaural hearing device system with the new binaural active occlusion cancellation circuit.

DETAILED DESCRIPTION OF THE DRAWINGS

(10) Various illustrative examples of the novel hearing device according to the appended claims will now be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments of novel hearing device are illustrated. The novel hearing device according to the appended claims may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. In addition, an illustrated embodiment needs not have all the aspects or advantages shown. An aspect or an advantage described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced in any other examples even if not so illustrated, or if not so explicitly described. It should also be noted that the accompanying drawings are schematic and simplified for clarity, and they merely show details which are essential to the understanding of the novel hearing device, while other details have been left out.

(11) As used herein, the singular forms a, an, and the refer to one or more than one, unless the context clearly dictates otherwise.

(12) FIG. 1 shows a block diagram of a known hearing device circuit 10 with an active occlusion cancellation circuit.

(13) The hearing device has a microphone 12 for provision of an input transducer audio signal in response to external sound received at the microphone 12. The input transducer audio signal is sampled and digitized in an A/D converter (not shown) and the buffer 14 groups the samples into blocks of samples for input to the transducer audio signal processor 16.

(14) The transducer audio signal processor 16 is adapted to process the sample blocks in accordance with a predetermined signal processing algorithm to generate processed blocks of samples, each of which is divided into a sequence of single samples in the unbuffer circuit 18 forming the processed input transducer audio signal 20.

(15) The processed input transducer audio signal 20 is input to a first input 22 of a signal combiner 24. A signal input at a second input 26 of the signal combiner 24 is subtracted from the processed input transducer audio signal 20 to reduce the occlusion effect by subtracting a signal that cancels undesired low frequency sound in the user's ear canal generated by low frequency amplification of body conducted sound, for example originating from the user's own voice, jaw motion, body impact, e.g, caused by walking, running, falling, etc. The body conducted sound is picked up by an ear canal microphone 28 that is accommodated in a housing (not shown) that is adapted to be positioned in an ear canal of the user whereby the ear canal microphone 28 is positioned to sense the ear canal sound pressure in the ear canal space inside the fully or partly occluded ear canal between a distal portion of the housing (not shown) and the ear drum (not shown). The ear canal sound pressure detected by the ear canal microphone 28 is a superposition of body conducted sound and output transducer emitted sound. The ear canal microphone 28 is adapted for provision of an ear canal microphone audio signal 30 in response to the ear canal sound pressure. The ear canal microphone audio signal 30 is sampled and digitized in an A/D converter 32 and the samples 34 are forwarded sequentially to the filter 36 that inputs a filtered ear canal audio signal 38 suitable for suppression of the occlusion effect at the second input 26 of the signal combiner 24, whereby the user perceives only the processed input transducer audio signal 20, without perception of body conducted sound.

(16) The signal combiner 24 provides an output transducer audio signal 40 that is equal to the processed input transducer audio signal 20 received at the first input 22 minus the signal 38 received at the second input 26 of the signal combiner 24 to a D/A converter 42 for conversion of the digital output transducer audio signal into an analogue signal that is converted in an output transducer 44 to an acoustic signal for emission towards the eardrum of the user.

(17) When x is the output transducer audio signal 40, u is the processed input transducer audio signal 20, o is the occlusion signal 46 that is desirably cancelled, y is the ear canal microphone audio signal 34, B is the transfer function of the filter 36, R is the transfer function from the input of the output transducer 44 to the output of the ear canal microphone 28 (y/x); then, slightly simplified, the output transducer audio signal x is given by:

(18) $\begin{array}{cc}x=\frac{u-\mathrm{Bt}}{1+\mathrm{BR}}& \left(1\right)\end{array}$
and the ear canal microphone audio signal y is given by:

(19) $\begin{array}{cc}y=\frac{\mathrm{Ru}+t}{1+\mathrm{BR}}& \left(2\right)\end{array}$
wherein the transfer function from the output transducer 44 to the output of the ear canal microphone 28 has been simplified to
y=Rx+t
ignoring possible non-linarites and attributing all signal delays to the output transducer 44.

(20) In the known active occlusion cancellation circuit 24, 28, 32, 36 shown in FIG. 1, it is not possible to distinguish between desired and undesired signals. As a consequence the main signal path of the circuit of FIG. 1 from the processed input transducer audio signal 20 to the output of the output transducer 44 requires additional amplification to obtain the same output signal as without the active occlusion cancellation circuit, i.e. the processed input transducer audio signal 20 has to be multiplied with [1+BR] for equalization, i.e. to compensate for the active occlusion cancellation circuit. This may lead to reduced dynamic range, e.g., by saturation at the output transducer for lower magnitudes of the compensated transducer audio signal 20 and/or an increase in the noise floor.

(21) FIG. 2 shows a block diagram of a known hearing device circuit 10 with another active occlusion cancellation circuit.

(22) Further active occlusion cancellation circuits are shown in co-pending European Patent Application No.: 16206073.5.

(23) The circuit 10 of FIG. 2 is identical to the circuit 10 of FIG. 1 apart from the fact that in the circuit of FIG. 2 a second filter 48 and a second signal combiner 50 have been added to the circuit 10 of FIG. 1. In FIG. 2, the first filter 36 and the first signal combiner 24 correspond to the filter 36 and the signal combiner 24, respectively, of FIG. 1.

(24) The second filter 48 models the transfer function of the signal path from the input of the output transducer 44 to the output of the ear canal microphone 28 (y/x) to distinguish the desired signal, namely the processed input transducer audio signal 20, from the undesired signal, namely the occlusion signal 46. Like the first filter 36, the second filter 48 operates sample based with very low delay.

(25) In the active occlusion cancellation circuit of FIG. 2, the equations (1) and (2) of the active occlusion cancellation circuit of FIG. 1 turn into:

(26) $\begin{array}{cc}x=\frac{u-\mathrm{Bt}}{1+B\left(R-A\right)}& \left(3\right)\\ y=\frac{\mathrm{Ru}+\left(1-\mathrm{AB}\right)t}{1+B\left(R-A\right)}& \left(4\right)\end{array}$

(27) Thus, in order to minimize the effect of the active occlusion cancellation circuit on the desired output signal of the output transducer 44, the transfer function A of the second filter 48 should match the transfer function R (y/x) from the input of the output transducer 44 to the output of the ear canal microphone 28, and |1AB| should be minimized, e.g. in a desired frequency range, e.g, utilizing least mean squares minimization techniques.

(28) As indicated by the denominator of equations (3) and (4), the circuit 10 of FIG. 2 may become unstable with changes in R, for example outside the ear, which makes insertion of the housing (not shown) with the output transducer 44 into the ear canal of the user rather uncomfortable. Also, the first and second filters 36, 48 may have to implement rather long impulse responses requiring many filter taps because the effective implementation is non-recursive, and which is not desirable since both filters operate sample-based at a high rate for low delay.

(29) FIG. 3 is a block diagram of a binaural hearing device system 1 falling under the terms of claim 1.

(30) The binaural hearing device system 1 of FIG. 3 is a binaural hearing aid system with active occlusion cancellation; however, it should be understood that another hearing device system falling under the terms of claim 1 and operating in accordance with claim 12 may not include hearing loss compensation and may not include active occlusion cancellation, for example another hearing device system falling under the terms of claim 1 and operating in accordance with claim 12 may include active noise cancellation and/or feedback cancellation.

(31) The illustrated binaural hearing device system 1 is a binaural hearing aid system 1. The illustrated binaural hearing device system 1 comprises a first hearing device 10A that is configured to provide compensation of hearing loss of the left ear of a user wearing the binaural hearing device system 1, and a second hearing device 10B that is configured to provide compensation of hearing loss of the right ear of the user.

(32) Each of the illustrated first hearing device 10A and second hearing device 10B comprises an input transducer comprising a set of external microphones 12A, 12B consisting of one external microphone 12A, 12B for provision of the input transducer audio signal in response to external sound and positioned outside the ear canal of the user wearing the binaural hearing device system 1; and an A/D converter (not shown) for provision of a digital transducer audio signal 14A, 14B in response to sound signals received at the external microphone 12A, 12B in a sound environment, a transducer audio signal processor 16A, 16B that is configured to process the digital transducer audio signals 14A, 14B in accordance with a predetermined signal processing algorithm to generate a hearing loss compensated audio signal 22A, 22B provided as a first input 22A, 22B to the first signal combiner 24A, 24B, and a D/A converter (not shown) and an output transducer 44A, 44B (also denoted a receiver in accordance with hearing aid terminology) for conversion of output 40A, 40B of the first signal combiner 24A, 24B to an acoustic output signal for emission towards the left and right ear drums, respectively, of the user wearing the binaural hearing device system 1.

(33) For simplicity, the operation of the binaural hearing device system 1 is explained for a system 1 wherein each of the illustrated first hearing device 10A and second hearing device 10B further comprises an AOC circuit similar to the prior art AOC circuit shown in FIG. 2. However, it should be noted that the AOC circuit may be substituted by any of the AOC circuits disclosed in co-pending European Patent Application No.: 16206073.5 or another known AOC circuit.

(34) Each of the AOC circuits has an ear canal microphone 28A, 28B for provision of the ear canal microphone audio signal 30A, 30B in response to sound inside the ear canal of the user wearing the binaural hearing device system 1; first signal combiner 24A, 24B; second signal combiner 50A, 50B; first filters 48A, 48B and an ear canal audio signal processor 36A, 36B, namely second filters 36A, 36B, for processing the ear canal audio signal 52A, 52B into a processed ear canal audio signal 38A, 38B, and wherein the AOC circuit operates as explained above with reference to FIGS. 1 and 2. In order to cancel occlusion, each of the illustrated first hearing device 10A and second hearing device 10B comprises the first combiner 24A, 24B configured for subtracting the processed ear canal audio signal 38A, 38B from the processed input transducer audio signal 22A, 22B, namely the hearing loss compensated audio signal, to produce the output transducer audio signal 40A, 40B.

(35) However, the prior art AOC circuit may cause distortion if the sound in the ear canal originating from the user body that it is desired to cancel has high amplitude. The resulting cancellation signal, i.e. the processed ear canal audio signal, may have even higher amplitude, and may cause distortion if the nominal dynamic range of the AOC circuit is exceeded, e.g. if the nominal dynamic range of the output transducer 44 and/or an amplifier is exceeded.

(36) Further, operation of the AOC circuit increases the noise level. This will especially be audible for users with normal hearing or mild hearing loss, and will be even more audible in quiet, e.g. using hearing protection.

(37) In the binaural hearing device system shown in FIG. 3, the prior art AOC circuit has been modified to suppress distortion and noise and binaural artefacts.

(38) Binaural artefacts caused by known AOC circuits include user perception of noise moving from one ear to the other, that the own voice sounds differently in the two ears, and other bothering effects.

(39) Excessive level is the situation wherein the operation of at least one of the AOC circuits of the first and second hearing devices 10A, 10B drives one or more components of the first and second hearing devices 10A, 10B, e.g. the output transducer, an amplifier, etc., outside its nominal dynamic range.

(40) Each of the illustrated first and second hearing devices 10A, 10B further comprises a signal level detector 58A, 58B connected to the output transducer audio signal 40A, 40B including the hearing loss compensated signal 22A, 22B, or the ear canal microphone audio signal 30A, 30B, or both; and configured for determining a signal level of the output transducer audio signal 40A, 40B, or the ear canal microphone audio signal 30A, 30B, or both.

(41) The first hearing device 10A comprises a first part 60A of the binaural excessive level detector 60A, 60B and the second hearing device 10B comprises a second part 60B of the binaural excessive level detector 60A, 60B, wherein the first part 60A of the binaural excessive level detector 60A, 60B is connected to the signal level detector 58A of the first hearing device 10A and the signal level detector 58B of the second hearing device 10B for reception of the output signals 62A, 62B with the determined signal levels, and configured for outputting the first control signal 64A to the ear canal audio signal processor 36A of the first hearing device 10A in response to the determined signal levels, and wherein the second part 60B of the binaural excessive level detector 60A, 60B is connected to the signal level detector 58A of the first hearing device 10A and the signal level detector 58B of the second hearing device 10B for reception of the output signals 62A, 62B with the determined signal levels, and configured for outputting the second control signal 64B to the ear canal audio signal processor 36B of the second hearing device 10B in response to the determined signal levels.

(42) In the illustrated first and second hearing devices 10A, 10B, the first part 60A and second part 60B of the binaural excessive level detector detect excessive level by comparison of each of the output signals 62A, 62B of the signal level detectors 58A, 58B with a predetermined threshold.

(43) In the illustrated example of FIG. 3, when at least one of the output signals 62A, 62B with the determined signal level exceeds the predetermined threshold, each of the control signals 64A, 64B controls the respective ear canal audio signal processor 36A, 36B, namely second filters 36A, 36B, to attenuate the respective processed ear canal audio signal 38A, 38B so that the dynamic range of the first and second hearing devices 10A, 10B is no longer exceeded.

(44) Each of the output signals 62A, 62B with the determined signal level, is forwarded to the respective one of the first part 60A and second part 60B of the binaural excessive level detector of the other hearing device 10B, 10A via the wireless transceivers 70A, 70B, and each of the first part 60A and second part 60B of the binaural excessive level detector determines the amount, e.g. in dB, needed to bring signal levels of audio signals of the first and second hearing devices 10A, 10B within the dynamic range of the first and second hearing devices 10A, 10B. Both control signals 64A, 64B then control the respective ear canal audio signal processor 36A, 36B to attenuate the processed ear canal audio signals 38A, 38B with the determined same amount, e.g. in dB, so that symmetric binaural attenuation of the processed ear canal audio signals 38A, 38B is performed (unless one of the processed ear canal audio signals 38A, 38B has a low magnitude and is attenuated to zero in which case symmetric attenuation cannot be obtained).

(45) Thus, the output transducer audio signals 40A, 40B are attenuated by the same amount, e.g. in dB, namely the value required to attenuate the output transducer audio signal 40A, 40B with the largest determined sound level within the dynamic range of the first and second hearing devices 10A, 10B, whereby binaural artefacts, such as user perception of noise moving from one ear to the other, user perception that the own voice sounds differently in the two ears, and other bothering effects.

(46) With the binaural excessive level detector 60A, 60B, it is possible to distinguish between one-sided occurrences of excessive level, i.e. excessive level occurring at one of the ears of the user wearing the binaural hearing device system 1, but not at the other ear of the user, e.g. caused by wind noise, user button operations, scratching helmet, etc., and two-sided excessive level, wherein excessive level occurs binaurally, i.e. simultaneously at both ears of the user.

(47) In the binaural hearing device system shown in FIG. 3, each of the illustrated first and second hearing devices 10A, 10B includes a body conducted sound detector 54A, 54B of the at least one body conducted sound detector, each of which is configured for detection of body conducted sound in the respective ear canal of the user of the binaural hearing device system 1. Body conducted sound is sound originating from the user's own body, for example originating from the user's own voice, jaw motion, body impact, e.g. caused by walking, running, falling, etc.

(48) In the binaural hearing device system shown in FIG. 3, each of the body conducted sound detectors 54A, 54B, utilizes that separation of body conducted sound from external sound is performed by second filter 48A, 48B and second signal combiner 50A, 50B. The second filter 48A, 48B models the transfer function from the input of the output transducer 44A, 44B to the output of the ear canal microphone 28A, 28B so that the output signal provided by the second filter 48A, 48B corresponds to the part of the ear canal microphone audio signal 30A, 30B originating from the output transducer 44A, 44B. This part is subtracted from the ear canal microphone audio signal 30A, 30B by the second signal combiner 50A, 50B thereby providing the part 52A, 52B of the ear canal microphone audio signal 30A, 30B, denoted the ear canal audio signal 52A, 52B; corresponding to the body conducted sound of the respective ear canal. The ear canal audio signal 52A, 52B is input to the body conducted sound detector 54A, 54B for detection of body conducted sound when present.

(49) In the binaural hearing device system shown in FIG. 3, each of the body conducted sound detectors 54A, 54B provides output signals 56A, 56B to each of the first part 60A and second part 60B of the binaural excessive level detectors 60A, 60B of the first and second hearing devices 10A, 10B providing information to the binaural excessive level detector 60A, 60B on whether body conducted sound is detected in both ears of the user wearing the binaural hearing device system 1, and possibly the type of body conducted sound detected, such as the user's own voice, sound caused by jaw movement, impact sound, etc., e.g. each type distinguished by characteristic spectral content.

(50) In the binaural hearing device system shown in FIG. 3, each of the first part 60A and second part 60B of the binaural excessive level detector of the first and second hearing devices 10A, 10B is configured so that the control signals 64A, 64B disables operation of the respective AOC circuit of the first and second hearing devices 10A, 10B, e.g. by setting the respective processed ear canal audio signal 38A, 38B to zero, when no body conducted sound is detected in any of the ear canals of the user wearing the binaural hearing device system 1. This function is optional and may not be present in other binaural hearing device systems according to the appended claims.

(51) In this way, it is possible to distinguish between one-sided occurrences of body conducted sound, i.e. body conducted sound occurring at one of the ears of the user, but not at the other ear of the user, e.g. caused by wind noise, user button operations, scratching helmet, etc., and two-sided, binaural body conducted sound caused by, e.g., the user's own voice, jaw movement, body impact with another object, etc., that in the binaural hearing device system shown in FIG. 3, leads to enablement of active occlusion cancellation in both the first and second hearing devices 10A, 10B.

(52) Disabling operation of the AOC circuit lowers noise, since the noise contribution from the AOC circuit is eliminated.

(53) In the illustrated binaural hearing device system 1 shown in FIG. 3, each of the illustrated first and second hearing devices 10A, 10B comprises a transducer audio signal processor 16A, 16B configured for compensation of the hearing loss of a user wearing the hearing device system 1. As is well known in the art of hearing devices, the processing of the transducer audio signal processors 16A, 16B are typically controlled by various selectable signal processing algorithms each of which having various parameters for adjustment of the actual signal processing performed, such as the various parameters of a dynamic range compressor performing hearing loss compensation as is well known in the art of hearing aids, and forming part of each of the transducer audio signal processors 16A, 16B shown in FIG. 3.

(54) In the illustrated binaural hearing device system 1 shown in FIG. 3, the inputs of each of the first filters 48A, 48B are connected to the output transducer audio signal 40A, 40B; however the inputs may instead be connected to the respective hearing loss compensated signal 22A, 22B as explained in more detail in co-pending European Patent Application No.: 16206073.5.

(55) In the illustrated hearing device system 1 shown in FIG. 3, each of the circuits 24A, 28A, 36A, 48A, 50A, 54A, 58A, 60A; 24B, 28B, 36B, 48B, 50B, 54B, 58B, 60B; and each of the respective transducer audio signal processor 16A, 16B of the first and second hearing devices 10A, 10B forms part of one respective common signal processor of the respective one of the first and second hearing devices 10A, 10B.

(56) In another binaural hearing device system (not shown), the signal processing of both the first and second hearing devices 10A, 10B is performed by one common signal processor, for example located in a housing of one of the first and second hearing devices 10A, 10B or in another housing of the binaural hearing device system, such as in a housing of a wearable device, such as a smartwatch, an activity tracker, a hand-held device, such as a smartphone, a remote control, etc., etc., forming part of the binaural hearing device system.

(57) In yet other binaural hearing device systems (not shown), the signal processing is performed by a plurality of signal processors, each of which, or parts of which, may be located in a housing of one of the first and second hearing devices 10A, 10B or in another housing of the binaural hearing device system, such as in another device, such as a wearable device, such as a smartwatch, an activity tracker, a hand-held device, such as a smartphone, a remote control, etc., etc., forming part of the binaural hearing device system.

(58) In the binaural hearing device system shown in FIG. 3, the first and second hearing devices 10A, 10B are interconnected in a Bluetooth LE wireless network for transmission of the control signals 56A, 56B, 62A, 62B between the first and second hearing devices 10A, 10B.

(59) As disclosed in US 2010/0220881 A1, occlusion may be caused by impact sound in the ear canal, e.g, generated by walking, running, or other types of body impact with another object, etc.

(60) The body conducted sound detectors 54A, 54B may include a binaural impact sound detector as disclosed in US 2010/0220881 A1 that is configured for detection of impact sound and may provide the control signals 56A, 56B in response to the detection of impact sound.

(61) Each of the body conducted sound detectors 54A, 54B may comprise an acceleration sensor and/or a vibration sensor in each of the illustrated first and second hearing devices 10A, 10B for detection of body conducted sound.

(62) Each of the binaural impact sound detectors 54A, 54B may comprise an acceleration sensor and/or a vibration sensor in each of the illustrated first and second hearing devices 10A, 10B, e.g. utilized for detection of human walking.

(63) The closure of the ear canal causing the occlusion effect may not be equally tight in both ears of the user wearing the binaural hearing device system 1, and thus may cause unequal acoustic leakage in the ear canals. In the binaural hearing device system 1 shown in FIG. 3, the signal level reduction controlled by the binaural excessive level detector 60A, 60B at each ear of the user is inversely proportional to the acoustic leakage in order to provide balanced occlusion cancellation in the two ears.

(64) In the binaural hearing device system 1 shown in FIG. 3, the binaural excessive level detector 60A, 60B provides acoustic leakage detection in each of the illustrated first and second hearing devices 10A, 10B.

(65) As mentioned above, each of the second filters 48A, 48B is intended to model the respective transfer function RA, RB from the input of the respective output transducer 44A, 44B to the output of the respective ear canal microphone 28A, 28B. The transfer functions RA, RB contain data about acoustic leakage.

(66) The first part 60A and second part 60B of the binaural excessive level detector receives data 68A, 68B on the transfer functions of the respective second filters 48A, 48B modelling the respective transfer functions RA, RB. The first part 60A and second part 60B of the binaural excessive level detector exchanges the data 72A, 72B between the first and second hearing devices 10A, 10B through the wireless transceivers 70A, 70B. The binaural excessive level detector 60A, 60B is configured for determination of a difference between the models of the transfer functions RA, RB of the respective hearing device 10A, 10B, preferably at low frequencies, such as frequencies below 2 kHz, such as frequencies below 1 kHz, such as frequencies below 700 Hz, such as frequencies in the range between 100 Hz and 700 Hz, such as frequencies around 500 Hz.

(67) The binaural excessive level detector 60A, 60B is configured for determination of the difference for the same settings of the first and second hearing devices 10A, 10B, and for attributing the determined difference to differences in acoustic leakage in the ear canals.

(68) Reference values of the transfer functions RA, RB of the first and second hearing devices 10A, 10B utilized for acoustic leakage detection, may be determined, e.g. during fitting in a dispenser's office with the hearing devices 10A, 10B properly mounted without acoustic leakage at the ears of the user, or during a sealed calibration performed at the factory, and the determined reference transfer functions may subsequently be used for comparisons with the respective same transfer functions determined later in order to detect possible acoustic leakage during normal use of the binaural hearing device system 1.

(69) In one embodiment, the binaural excessive level detector 60A, 60B is configured for determining a difference between the reference transfer functions and the respective same transfer functions determined during normal use of the binaural hearing device system 1, and for modifying the control signals 64A, 64B in accordance with the determined difference when the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signals 38A, 38B have to be attenuated to bring signals of the first and second hearing devices 10A, 10B within the dynamic range of the first and second hearing devices 10A, 10B.

(70) For example, the binaural excessive level detector 60A, 60B may be configured for modification of the control signals 64A, 64B when the determined difference is larger than a predetermined or adjustable threshold at one or more predetermined frequencies when the binaural excessive level detector 60A, 60B and when the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signals 38A, 38B have to be attenuated to bring signals of the first and second hearing devices 10A, 10B within the dynamic range of the first and second hearing devices 10A, 10B.

(71) Utilization of reference transfer functions has the advantage that individual differences between the anatomy of the ears of the user and individual differences between the hearing devices worn at opposite ears of the user, are taken into account.

(72) In presence of acoustic leakage, the binaural excessive level detector 60A, 60B is configured to output modified control signals 64A, 64B to control the respective ear canal audio signal processors 36A, 36B of the first and second hearing devices 10A, 10B to attenuate the respective processed ear canal audio signals 38A, 38B to be inversely proportional to the acoustic leakage at the frequencies at which the acoustic leakage is detected, in order to provide balanced occlusion cancellation in the two ears, wherein the obtained occlusion cancellation in each ear is the sum of reduction by acoustic leakage and the active occlusion cancellation provided by subtracting the respective processed ear canal audio signal 38A, 38B from the respective processed input transducer audio signal 22A, 22B.

(73) For example, for a specific frequency range, such as a frequency range including 500 Hz, in the event that 1 dB acoustic leakage is detected for the first hearing device 10A and 8 dB acoustic leakage is detected for the second hearing device 10B, and the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signal 38A has to be attenuated by 10 dB in the first hearing device 10A to bring the output transducer audio signal 40A within the dynamic range of the output transducer 44A, then the binaural excessive level detector 60A controls the ear canal audio signal processor 36A to attenuate the processed ear canal audio signal 38A with the required 10 dB in the hearing device 10A (since the determination relating to dynamic range is performed in presence of the 1 dB acoustic leakage), and the binaural excessive level detector 60B controls the ear canal audio signal processor 36B of the second hearing device 10B to attenuate the processed ear canal audio signal 38B with 10 dB minus the acoustic leakage difference in dB (8 dB1 dB=7 dB), i.e. with 10 dB7 dB=3 dB, to obtain balanced occlusion cancellation in the two ears, wherein the obtained occlusion cancellation in each ear is the sum of reduction by acoustic leakage and the active occlusion cancellation provided by subtracting the respective processed ear canal audio signal 38A, 38B from the respective processed input transducer audio signal 22A, 22B.

(74) The attenuation may be limited by the magnitude of the signal to be attenuated. For example, if the signal is 10 dB and the desire attenuation is 15 dB, the attenuation would result in amplification of the signal. This is not desired, and instead, the signal is attenuated to 0 dB resulting in a, typically brief, unbalanced occlusion cancellation.

(75) In another embodiment, use of reference values of the transfer functions of the first and second hearing devices 10A, 10B is avoided by assuming that the one of the first and second hearing devices 10A, 10B with the highest level of the ear canal microphone audio signal 30A, 30B at the frequencies at which acoustic leakage is detected, exhibits no acoustic leakage.

(76) In this embodiment, the binaural excessive level detector 60A, 60B is configured for determining a difference between the transfer function, or combination of transfer functions, selected for acoustic leakage detection, of the first and second hearing devices 10A, 10B, and for modifying the control signals 64A, 64B in accordance with the determined differences when the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signals 38A, 38B have to be attenuated to bring signals of the first and second hearing devices 10A, 10B within the dynamic range of the first and second hearing devices 10A, 10B. For example, the binaural excessive level detector 60A, 60B may be configured for modification of the control signals 64A, 64B when a determined difference is larger than a predetermined or adjustable threshold at one or more predetermined frequencies.

(77) The one of the first and second hearing devices 10A, 10B with the highest level of the ear canal microphone audio signal 30A, 30B at the frequencies at which acoustic leakage is detected, is the minuend so that the determined difference is larger than or equal to zero.

(78) In presence of acoustic leakage, the binaural excessive level detector 60A, 60B is configured to output modified control signals 64A, 64B to control the respective ear canal audio signal processors 36A, 36B of the first and second hearing devices 10A, 10B to attenuate the respective processed ear canal audio signals 38A, 38B to be inversely proportional to the acoustic leakage at the frequencies at which the acoustic leakage is detected, in order to provide balanced occlusion cancellation in the two ears of the user, wherein the obtained occlusion cancellation in each ear is the sum of reduction by acoustic leakage and the active occlusion cancellation provided by subtracting the respective processed ear canal audio signal 38A, 38B from the respective processed input transducer audio signal 22A, 22B.

(79) For example, for a specific frequency range, such as a frequency range including 500 Hz, in the event that the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signal 38A has to be attenuated by 10 dB in the first hearing device 10A to bring the output transducer audio signal 40A within the dynamic range of the output transducer 44A, and that the binaural excessive level detector 60A, 60B has determined a difference of 7 dB attributed to acoustic leakage of the second hearing device 10B, then the binaural excessive level detector 60A controls the ear canal audio signal processor 36A to attenuate the processed ear canal audio signal 38A with the required 10 dB in the hearing device 10A, and the binaural excessive level detector 60B controls the ear canal audio signal processor 36B of the second hearing device 10B to attenuate the processed ear canal audio signal 38B with 10 dB minus the acoustic leakage difference 7 dB=3 dB to obtain balanced occlusion cancellation in the two ears, wherein the obtained occlusion cancellation in each ear is the sum of reduction by acoustic leakage and the active occlusion cancellation provided by subtracting the respective processed ear canal audio signal 38A, 38B from the respective processed input transducer audio signal 22A, 22B.

(80) The attenuation may be limited by the magnitude of the signal to be attenuated. For example, if the signal is 10 dB and the desired attenuation is 15 dB, the attenuation would result in amplification of the signal. This is not desired, and instead, the signal is attenuated to 0 dB resulting in a, typically brief, unbalanced occlusion cancellation. In each of, or one of, the first and second hearing devices 10A, 10B, the AOC circuit may be configured for reducing gain with the same amount, e.g. in dB, in a plurality of the frequency bands of the ear canal microphone audio signal in response to the control signals provided by the binaural excessive level detector 60A, 60B.

(81) In each of, or one of, the first and second hearing devices 10A, 10B, the AOC circuit may be configured for reducing gain individually in a plurality of the frequency bands of the AOC circuit in response to the control signals provided by the binaural excessive level detector 60A, 60B.

(82) In each of, or one of, the first and second hearing devices 10A, 10B, the AOC circuit may be configured for reducing gain as a function of broad-band power of the ear canal microphone audio signal in response to the control signals provided by the binaural excessive level detector 60A, 60B.

(83) In each of, or one of, the first and second hearing devices 10A, 10B, signal processing parameters of the AOC circuit may be adjustable in accordance with user inputs to a user interface (not shown) of the binaural hearing device system 1.

(84) FIG. 4 is a block diagram of another binaural hearing device system 1 falling under the terms of claim 1.

(85) The binaural hearing device system 1 shown in FIG. 4 is similar to and operates in the same way as the binaural hearing device system 1 shown in FIG. 3 apart from the fact that acoustic leakage detection in the hearing device system 1 of FIG. 4 does not involve the transfer functions of the second filters 48A, 48B modelling the respective transfer functions RA, RB as in the binaural hearing device system shown in FIG. 3.

(86) Apart from this, the binaural excessive level detector 60A, 60B performs all the functions of the binaural excessive level detector 60A, 60B of the binaural hearing device system 1 shown in FIG. 3 and receives the same inputs and provides the same outputs as the binaural excessive level detector 60A, 60B of the binaural hearing device system 1 shown in FIG. 3.

(87) In the binaural hearing device system 1 shown in FIG. 4, each of the first and second hearing devices 10A, 10B comprises an acoustic leakage detector 74A, 74B for providing data on acoustic leakage, preferably at low frequencies, such as frequencies below 2 kHz, such as frequencies below 1 kHz, such as frequencies below 700 Hz, such as frequencies in the range between 100 Hz and 700 Hz, such as frequencies around 500 Hz.

(88) The acoustic leakage detector 74A of the first hearing device 10A has 3 inputs that are connected so that the input transducer audio signal 14A is provided to one of the inputs, the output transducer audio signal 40A is provided to another input, and the ear canal microphone audio signal 30A is provided to the third input. The acoustic leakage detector 74A is configured for determination of a transfer function that involves the sound pressure in the ear canal space inside the fully or partly occluded ear canal, for example the transfer function from the output 14A of the input transducer 12A to the input 40A of the output transducer 44A, and/or the transfer function of a feedback loop from the input 40A of the output transducer 44A to the output 14A of the input transducer 12A, and/or the transfer function from the input 40A of the output transducer 44A to the output 30A of the ear canal microphone 28A.

(89) Similarly, the acoustic leakage detector 74B of the second hearing device 10B has 3 inputs that are connected so that the input transducer audio signal 14B is provided to one of the inputs, the output transducer audio signal 40B is provided to another input, and the ear canal microphone audio signal 30B is provided to the third input. The acoustic leakage detector 74B is configured for determination of a transfer function that involves the sound pressure in the ear canal space inside the fully or partly occluded ear canal, for example the transfer function from the output 14B of the input transducer 12B to the input 40B of the output transducer 44B, and/or the transfer function of a feedback loop from the input 40B of the output transducer 44B to the output 14B of the input transducer 12B, and/or the transfer function from the input 40B of the output transducer 44B to the output 30B of the ear canal microphone 28B.

(90) The acoustic leakage detectors 74A, 74B are configured for determination of the same respective selected transfer function, or a same combination of respective selected transfer functions, of the respective first and second hearing devices 10A, 10B with the same settings of the first and second hearing devices 10A, 10B.

(91) Each of the acoustic leakage detectors 74A, 74B has an output 76A, 76B for outputting data on the determined transfer functions to the binaural excessive level detector 60A, 60B, and the binaural excessive level detector 60A, 60B is configured for processing the determined transfer functions in order to determine possible acoustic leakage.

(92) Reference values of the transfer functions of the first and second hearing devices 10A, 10B utilized for acoustic leakage detection, may be determined, e.g. during fitting in a dispenser's office with the hearing devices 10A, 10B properly mounted without acoustic leakage at the ears of the user, or during a sealed calibration performed at the factory, and the determined reference transfer functions may subsequently be used for comparisons with the respective transfer functions determined later in order to detect possible acoustic leakage during normal use of the binaural hearing device system 1.

(93) In one embodiment, the binaural excessive level detector 60A, 60B is configured for determining a difference between the reference transfer functions and the respective transfer functions determined during normal use of the binaural hearing device system 1, and for modifying the control signals 64A, 64B in accordance with the determined differences when the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signals 38A, 38B have to be attenuated to bring signals of the first and second hearing devices 10A, 10B within the dynamic range of the first and second hearing devices 10A, 10B.

(94) For example, the binaural excessive level detector 60A, 60B may be configured for modification of the control signals 64A, 64B when the determined difference is larger than a predetermined or adjustable threshold at one or more predetermined frequencies when the binaural excessive level detector 60A, 60B and when the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signals 38A, 38B have to be attenuated to bring signals of the first and second hearing devices 10A, 10B within the dynamic range of the first and second hearing devices 10A, 10B.

(95) Utilization of reference transfer functions has the advantage that individual differences between the anatomy of the ears of the user and individual differences between the hearing devices worn at opposite ears of the user, are taken into account.

(96) In presence of acoustic leakage, the binaural excessive level detector 60A, 60B is configured to output modified control signals 64A, 64B to control the respective ear canal audio signal processors 36A, 36B of the first and second hearing devices 10A, 10B to attenuate the respective processed ear canal audio signals 38A, 38B to be inversely proportional to the acoustic leakage at the frequencies at which the acoustic leakage is detected, in order to provide balanced occlusion cancellation in the two ears, wherein the obtained occlusion cancellation in each ear is the sum of reduction by acoustic leakage and the active occlusion cancellation provided by subtracting the respective processed ear canal audio signal 38A, 38B from the respective processed input transducer audio signal 22A, 22B.

(97) For example, for a specific frequency range, such as a frequency range including 500 Hz, in the event that 1 dB acoustic leakage is detected for the first hearing device 10A and 8 dB acoustic leakage is detected for the second hearing device 10B, and the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signal 38A has to be attenuated by 10 dB in the first hearing device 10A to bring the output transducer audio signal 40A within the dynamic range of the output transducer 44A, then the binaural excessive level detector 60A controls the ear canal audio signal processor 36A to attenuate the processed ear canal audio signal 38A with the required 10 dB in the hearing device 10A (since the detection is performed in presence of the 1 dB acoustic leakage), and the binaural excessive level detector 60B controls the ear canal audio signal processor 36B of the second hearing device 10B to attenuate the processed ear canal audio signal 38B with 10 dB minus the acoustic leakage difference in dB (8 dB1 dB=7 dB), i.e. with 10 dB7 dB=3 dB to obtain balanced occlusion cancellation in the two ears, wherein the obtained occlusion cancellation in each ear is the sum of reduction by acoustic leakage and the active occlusion cancellation provided by subtracting the respective processed ear canal audio signal 38A, 38B from the respective processed input transducer audio signal 22A, 22B.

(98) The attenuation may be limited by the magnitude of the signal to be attenuated. For example, if the signal is 10 dB and the attenuation is 15 dB, the attenuation would result in amplification of the signal. This is not desired, and instead, the signal is attenuated to 0 dB resulting in a, typically brief, unbalanced occlusion cancellation.

(99) In another embodiment, use of reference values of the transfer functions of the first and second hearing devices 10A, 10B is avoided by assuming that the one of the first and second hearing devices 10A, 10B with the highest level of the ear canal microphone audio signal 30A, 30B at the frequencies at which acoustic leakage is detected, exhibits no acoustic leakage.

(100) In this embodiment, the binaural excessive level detector 60A, 60B is configured for determining a difference between the transfer function, or combination of transfer functions, selected for acoustic leakage detection, of the first and second hearing devices 10A, 10B, and for modifying the control signals 64A, 64B in accordance with the determined differences when the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signals 38A, 38B have to be attenuated to bring signals of the first and second hearing devices 10A, 10B within the dynamic range of the first and second hearing devices 10A, 10B. For example, the binaural excessive level detector 60A, 60B may be configured for modification of the control signals 64A, 64B when a determined difference is larger than a predetermined or adjustable threshold at one or more predetermined frequencies.

(101) The one of the first and second hearing devices 10A, 10B with the highest level of the ear canal microphone audio signal 30A, 30B at the frequencies at which acoustic leakage is detected, is the minuend so that the determined difference is larger than or equal to zero. The acoustic leakage detectors 74A, 74B are configured for determination of the same respective selected transfer function, or a same combination of respective selected transfer functions, of the respective first and second hearing devices 10A, 10B with the same settings of the first and second hearing devices 10A, 10B.

(102) In presence of acoustic leakage, the binaural excessive level detector 60A, 60B is configured to output modified control signals 64A, 64B to control the respective ear canal audio signal processors 36A, 36B of the first and second hearing devices 10A, 10B to attenuate the respective processed ear canal audio signals 38A, 38B to be inversely proportional to the acoustic leakage at the frequencies at which the acoustic leakage is detected, in order to provide balanced occlusion cancellation in the two ears of the user, wherein the obtained occlusion cancellation in each ear is the sum of reduction by acoustic leakage and the active occlusion cancellation provided by subtracting the respective processed ear canal audio signal 38A, 38B from the respective processed input transducer audio signal 22A, 22B.

(103) For example, for a specific frequency range, such as a frequency range including 500 Hz, in the event that the binaural excessive level detector 60A, 60B has determined that the processed ear canal audio signal 38A has to be attenuated by 10 dB in the first hearing device 10A to bring the output transducer audio signal 40A within the dynamic range of the output transducer 44A, and that the binaural excessive level detector 60A, 60B has determined a difference of 7 dB attributed to acoustic leakage of the second hearing device 10B, then the binaural excessive level detector 60A controls the ear canal audio signal processor 36A to attenuate the processed ear canal audio signal 38A with the required 10 dB in the hearing device 10A, and the binaural excessive level detector 60B controls the ear canal audio signal processor 36B of the second hearing device 10B to attenuate the processed ear canal audio signal 38B with 10 dB minus the acoustic leakage difference 7 dB=3 dB to obtain balanced occlusion cancellation in the two ears, wherein the obtained occlusion cancellation in each ear is the sum of reduction by acoustic leakage and the active occlusion cancellation provided by subtracting the processed ear canal audio signal 38A, 38B from the respective processed input transducer audio signal 22A, 22B.

(104) The attenuation may be limited by the magnitude of the signal to be attenuated. For example, if the signal is 10 dB and the attenuation is 15 dB, the attenuation would result in amplification of the signal. This is not desired, and instead, the signal is attenuated to 0 dB resulting in a, typically brief, unbalanced occlusion cancellation.

(105) FIG. 5 is a block diagram of yet another binaural hearing device system 1 falling under the terms of claim 1.

(106) The binaural hearing device system 1 shown in FIG. 5 is similar to, and operates in the same way as, the binaural hearing device system 1 shown in FIG. 3 apart from the fact that the binaural hearing device system 1 of FIG. 5 comprises a wearable device 10C, namely a smartphone 10C, wherein the smartphone 10C comprises the binaural excessive level detector 60C.

(107) The binaural excessive level detector 60C performs all the functions of the binaural excessive level detector 60A, 60B of the binaural hearing device system 1 shown in FIG. 3 and receives the same inputs and provides the same outputs as the binaural excessive level detector 60A, 60B of the binaural hearing device system 1 shown in FIG. 3.

(108) In the binaural hearing device system 1 shown in FIG. 5, each of the first hearing device 10A, the second hearing device 10B, and the smartphone 10C, comprises a transceiver 70A, 70B, 70C that is configured for communication with each other in accordance with the Bluetooth Low Energy standard protocol so that the first and second hearing devices 10A, 10B and the smartphone 10C of the binaural hearing device system shown in FIG. 5, are interconnected in a Bluetooth Low Energy wireless network for transmission of the control signals 64A, 64B from the binaural excessive level detector 60C of the smartphone 10C to the first and second hearing devices 10A, 10B and for transmission of the output signals 56A, 56B of the respective body conducted sound detectors 54A, 54B and the output signals 62A, 62B of the respective signal level detectors 58A, 58B and the output signals 68A, 68B containing data on the transfer functions of the respective second filters 48A, 48B modelling the respective transfer functions RA, RB of the respective second filters 48A, 48B from the first and second hearing devices 10A, 10B to the binaural excessive level detector 60C of the smartphone 10C.

(109) The smartphone 10C further comprises a user interface (not shown) that is configured for user control of the binaural hearing device 1, e.g. for selection of a specific signal processing algorithm, and/or for adjustment of a signal processing parameter, such as the volume, the threshold of the binaural excessive level detector 10C, etc.

(110) FIG. 6 is a block diagram of yet another binaural hearing device system 1 falling under the terms of claim 1.

(111) The binaural hearing device system 1 shown in FIG. 6 is similar to, and operates in the same way as, the binaural hearing device system 1 shown in FIG. 4 apart from the fact that the binaural hearing device system 1 of FIG. 6 comprises a wearable device 10C, namely a smartphone 10C, wherein the smartphone 10C comprises the binaural excessive level detector 60C.

(112) The binaural excessive level detector 60C performs all the functions of the binaural excessive level detector 60A, 60B of the binaural hearing device system 1 shown in FIG. 4 and receives the same inputs and provides the same outputs as the binaural excessive level detector 60A, 60B of the binaural hearing device system 1 shown in FIG. 4.

(113) In the binaural hearing device system 1 shown in FIG. 6, each of the first hearing device 10A, the second hearing device 10B, and the smartphone 10C, comprises a transceiver 70A, 70B, 70C that is configured for communication with each other in accordance with the Bluetooth Low Energy standard protocol so that the first and second hearing devices 10A, 10B and the smartphone 10C of the binaural hearing device system shown in FIG. 6, are interconnected in a Bluetooth Low Energy wireless network for transmission of the control signals 64A, 64B from the binaural excessive level detector 60C of the smartphone 10C to the first and second hearing devices 10A, 10B and for transmission of the output signals 56A, 56B of the respective body conducted sound detectors 54A, 54B and the output signals 62A, 62B of the respective signal level detectors 58A, 58B and the output signals 68A, 68B containing data on the transfer functions of the respective second filters 48A, 48B modelling the respective transfer functions RA, RB of the respective second filters 48A, 48B from the first and second hearing devices 10A, 10B to the binaural excessive level detector 60C of the smartphone 10C.

(114) The smartphone 10C further comprises a user interface (not shown) that is configured for user control of the binaural hearing device 1, e.g. for selection of a specific signal processing algorithm, and/or for adjustment of a signal processing parameter, such as the volume, the threshold of the binaural excessive level detector 10C, etc.

(115) Although particular embodiments have been shown and described, it will be understood that it is not intended to limit the claimed inventions to the preferred embodiments, and it will be obvious to those skilled in the art that various changes and modifications may be made without department from the spirit and scope of the claimed inventions. The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense. The claimed inventions are intended to cover alternatives, modifications, and equivalents.