Technical Field

The invention relates to a hearing system according to the preamble of claim 1 and to a method for operating such a hearing system according to the preamble of claim 14.

Hearing systems are systems which are related to the hearing of individuals, as for example hearing aids which compensate for a hearing loss, communication systems which provide communication as for example telephones, hearing protection which protects hearing in noisy environments and headsets which deliver or pick-up sound at the head of an individual .

Background of the Invention

If hearing systems are body-worn, i.e. to be worn at and/or in the body of an individual, it is an important issue that they do not rely on a wire bound power supply. Firstly, this enables the individual to move around freely and, secondly, there are no or less conspicuous cables which might be cosmetically distracting. Hence, a battery is often used as power supply.

In the case of modular hearing systems, more than one module might need to be supplied with power. In this case,

P208727 a battery is usually foreseen only in one of the modules, and the other modules are powered by this battery as well as by means of power supply wires connecting the different modules of the system. This solution has the advantage that the user has to replace or recharge only one battery.

However, this solution has also the disadvantage that it requires additional wires in the module connectors, which adds to the complexity of the hearing system and may also be undesirable cosmetically due to the increased thickness of the module connectors.

WO 2008 / 010716 A2 discloses a hearing aid with a housing to be worn outside an ear of a user which co-acts with an in-the-ear part. A microphone and a loudspeaker are accommodated in the in-the-ear part. A primary power supply and a processing device are accommodated in the outside part. The in-the-ear part may comprise a capacitor as a secondary power supply. A DC/DC converter may be used to generate an almost fixed direct voltage from the variable voltage received from a capacitor.

According to the principle of "phantom power" or "phantom feed" it is known to supply landline telephones or studio microphones with power over signal lines.

US 5,814,095 discloses an implantable hearing aid microphone which is powered by phantom feed. One pin carries the useful signal potential and the power-supply DC voltage potential jointly.

P208727 US 6,600,825 discloses a behind-the-ear hearing aid with an electro-acoustic converter. The converter may be integrated into an ear fitting piece. The ear fitting piece may be mechanically connected to the behind-the-ear hearing aid via a flexibly deformable coupling element which contains the electrical feed line to the converter. The converter may comprise a converter driver accommodated in the converter housing. The electrical supply for the converter driver may be provided using the principle of phantom feed through a two-pole electrical connection, the DC voltage which supplies the converter driver being superimposed on a signal-containing AC voltage. The hearing aid may have a pulse-width modulated output stage.

Generally, it can be concluded that in the field of modular hearing systems, it is known to provide only a first module with a replaceable or rechargeable battery, while the other modules are powered by this first module. According to the principle of "phantom power" it is also known to supply power over signal lines. However, the application of the principle of "phantom power" in regard to transmitting power between different body-worn modules of a hearing system is still imperfect. Phantom power is only used, as in the example of US 5,814,095, for powering a microphone with power transmitted over its signal line, or as in US 6,600,825, for processing and/or amplifying a receiver signal with power taken from the receiver signal. Apart from these two special cases, always separate power lines are provided in the module connectors if power is to be

P208727 transmitted between different body-worn modules of a hearing system.

Summary of the Invention

In the present document the term "hearing system" is used. It is meant to include

- hearing aids, which compensate for the hearing loss of an individual,

- hearing protectors, which protect hearing against loud environment noises,

- communication systems, which allow communication between individuals, - headsets which deliver and/or pick up sound at a head of a user,

- any combination of the above mentioned.

In the present document the term "module" is used. Modules are functional units which are operationally connected to each other. A modular hearing system comprises a least two modules. The modules may be designed to be worn at different locations at the head, as for example in the ear or behind the ear.

The invention addresses the problem to provide a hearing system, which is less conspicuous, less complex and/or more reliable than known hearing systems.

P208727 This problem is solved by the features of claim 1, namely by a hearing system comprising a first module and a second module which modules are configured to be body-worn, wherein said first module and said second module are electrically connected to each other by a connection, wherein said second module comprises a receiver, wherein said first module is designed to provide a receiver signal for said receiver, wherein said second module comprises a power supply means for generating a supply voltage from said receiver signal, characterized in that said second module comprises one or more electrically powered non- receiver signal components, which are components other than components configured for processing and/or amplifying said receiver signal for said receiver, wherein said one or more non-receiver signal components are configured to be powered by said supply voltage.

The problem is also solved by the features of claim 14, namely by a method for operating a hearing system comprising a first module and a second module, which modules are configured to be body-worn, said method comprising the steps of:

- providing a receiver signal in said first module for a receiver arranged in said second module, - transmitting said receiver signal electrically to said second module via a module connection,

- generating a supply voltage from said receiver signal in said second module,

- using said supply voltage for powering non-receiver signal components, which are components other than

P208727 components configured for processing and/or amplifying said receiver signal for said receiver.

The invention overcomes the existing prejudice that a receiver signal might not be suitable to power anything else than the receiver. The invention opens up the possibility to fully avoid a separate power supply line in the module connection. Besides of being inconspicuous, relatively simple and/or reliable solutions according to the invention also have the advantage that they can be implemented based on existing conventional system parts or modules, for example by using as a first module the behind- the-ear module of a conventional canal receiver technology hearing aid and enhancing it with a sound cancellation subsystem ear-piece module as described in more detail below. Hence, the invention is also well suited to be carried out in an economically favourable way. It may be carried out in conjunction with a business method which incorporates the partial purchase of a hearing aid, having the advantage for the customer that the cost may be spread over time.

A further aspect of the invention addresses the problem of powering an active sound cancellation subsystem which is arranged in a hearing system in an inconspicuous, simple and reliable way.

This problem is solved by the features of claim 4.

P208727 A further aspect of the invention addresses the problem of providing a receiver signal which is especially well suited for generating a power supply voltage from the receiver signal and/or which is well suited for carrying control information.

This problem is solved by the features of claim 7.

The advantages of the methods correspond to the advantages of corresponding devices and vice versa.

Further embodiments and advantages emerge from the dependent claims and the description referring to the figures .

Brief Description of the Drawings

Below, the invention is described in more detail by referring to drawings showing exemplified embodiments.

Fig. 1 shows a hearing system comprising a behind-the- ear module and an ear-piece module;

Fig. 2 shows an ear-piece module of a hearing system illustrating different subsystems according to embodiments of invention;

Fig. 3 shows a schematic diagram of a behind-the-ear module and of an ear-piece module of a hearing

P208727 system according to an embodiment of the invention;

Fig. 4 shows a schematic diagram of an ear-piece module of a hearing system comprising a microphone subsystem according to an embodiment of the invention;

Fig. 5 shows a schematic diagram of an ear-piece module comprising a drive subsystem of a hearing system according to an embodiment of the invention;

Fig. 6 shows a signal diagram of a pulse width modulated receiver signal and the resulting receiver membrane displacement in case of a sine wave environment sound;

Fig. 7 shows a signal diagram of a pulse width modulated receiver signal and the resulting receiver membrane displacement in case of silence and a first static position of the receiver membrane;

Fig. 8 shows a signal diagram of a pulse width modulated receiver signal and the resulting receiver membrane displacement in case of silence and a second static position of the receiver membrane; and

Fig. 9 shows a signal diagram of a pulse width modulated receiver signal and the resulting receiver

P208727 membrane displacement in case of silence and a third static position of the receiver membrane.

The reference symbols used in the figures and their meaning are summarized in a list of reference symbols. The described embodiments are meant as examples and shall not confine the invention.

Detailed Description of the Invention

Fig. 1 shows an example of a hearing system according to the state of the art, namely a CRT (canal receiver technology) hearing aid. It comprises a behind the-ear module 1 and an ear-piece module 2. Ear-piece module 2 is designed to be worn in the ear and in particular partially or fully in the ear-canal. The two modules are connected by a connection 4. Besides of this connection the hearing system is "wireless", i.e. the hearing system can be operated independendly of and without wires leading to components not worn at and/or in the body of the individual carrying the hearing system. The behind-the-ear module 1 comprises a battery 3 and an amplifier 5. The battery 3 is configured to be exchangeable and/or rechargeable by the user. The ear-piece module 2 comprises a loudspeaker, or, according to the terminology used in the field of hearing aids, a receiver 6. The receiver 6 is connected to the amplifier 5 a receiver signal line and a reference potential line. Accordingly, the connection 4 comprises two electrical conductors. Such hybrid behind-the-ear/in-the-

P208727 ear hearing systems have the advantage that they combine some of the advantages of in-the-ear devices and behind- the-ear devices. They are relatively inconspicuous but are still capable of providing a reasonable amount of amplification. Arranging the main microphone and the receiver in different modules has the advantage of a reduced susceptibility to feedback compared to conventional one-module solutions. Besides of the shown components, namely two modules 1, 2 and their connection 4, the hearing system might comprise further components, such as, for example, a remote control or a fitting device.

Fig. 2 shows an ear-piece module 2 of a hearing system according to the invention. In one embodiment of the invention such an ear-piece module 2 is used as a module of a hearing device in a configuration which corresponds to that shown in Fig. 1. However, it may also be used for a communication system, a hearing protector or a headset. The ear-piece module 2 is inserted in an ear canal 32 and comprises a vent passage 31. A receiver signal for receiver 6 is transmitted over connection 4 from a further module, which is not shown and which may be a behind-the-ear module. Power supply means 16 in the ear-piece module 2 generates a supply voltage from this receiver signal. The supply voltage is used for powering one or more non- receiver signal components, i.e. components other than components configured for processing or amplifying said receiver signals. The Fig. 2 illustrates different subsystems which include such non-receiver signal components and which may be fully or partially powered by

P208727 said supply voltage. It is to be noted that in an actual embodiment only one or a subset of such subsystems may be employed. The subsystems include the following:

- An environment microphone subsystem 7 which picks up sound from the environment of the hearing system user. Picking up environment sound from within the ear canal or at least from within the ear has the advantage that the so called microphone location effect is smaller than in the case of picking up the environment sound at the behind-the-ear module of the hearing system. The hearing system reproduces environment sounds more naturally and information such as spatial cues are better preserved. An environment microphone in an ear- piece module is described in more detail in WO

2008/010716 A2. As in any microphone subsystem, the supply voltage may be used for a current or voltage biasing of the microphone and/or for an amplifier amplifying the microphone signal.

- A canal microphone subsystem 8 which picks up sound from the ear canal 32, or, more precisely, from the space between the ear-piece module 2 and the eardrum. This signal can be used for many purposes, in particular for cancelling own-voice, for cancelling environment noise, for controlling the correct functioning of the receiver 6, for measuring auditory echoes or responses such as otoacoustic emissions, for measuring acoustical coupling parameters and/or for detection of insertion, positioning and removal of the

P208727 ear-piece module 2. A canal microphone is described in more detail in US 4,596,902.

- A vent microphone subsystem 9 which picks up sound from within the vent passage 31. It can be used to cancel so called direct sound passing through the vent passage 31 to the ear-drum without processing. It can further be used for feedback suppression by cancelling sound passing from the receiver 6 to any of the environment sound microphones, such as the one of environment microphone subsystem 7. A vent microphone is described in more detail in US 6,920,227.

- A vent loudspeaker subsystem 10 allows to emit sound into the vent passage 31. It can be used for generating anti-sound for the already mentioned cancellation purposes regarding direct sound and feedback. A vent loudspeaker is described in more detail in US 6,920,227.

- A vent valve drive subsystem 11 allows to adjust the aperture of vent passage 31. When the hearing system user speaks himself it might be desirable to fully open the vent passage 31 to avoid the occlusion effect. If the hearing system user is in a noisy environment and a sound is picked up by a directional microphone it might be desirable to fully close the vent passage 31 to avoid direct sound. More details on how to implement an electrically actuated vent valve are disclosed in US 6,549,635 and WO 2007/054589 A2.

8727 - An active sound cancellation subsystem, such as illustrated by first, second and third cancellation subsystem 12, 13 and 14, can be targeted at cancelling direct sound, own-voice and/or feedback. For cancellation generally sound is picked up by one or more microphones, in particular the microphone of environment microphone subsystem 7, of canal microphone subsystem 8 and/or of vent microphone subsystem 9. The sound is at least partially cancelled by emitting a cancellation sound, in particular an inverted sound or anti-sound, over one or more loudspeakers such as receiver 6 or the loudspeaker of the vent loudspeaker subsystem 10. There is a circuit for the generation of the cancellation sound signal. Said generation may comprise a digital processing, in particular in the frequency domain. It is to be noted that such a cancellation subsystem can work substantially independent from the primary hearing system. For example, a receiver-only ear-piece module of a conventional hearing system may be replaced with the cancellation ear-piece module 2, wherein the cancellation subsystem is powered by said ear-piece power supply means 16, which in turn takes its power from the receiver signal provided, for example, by a behind-the-ear module. It might not be necessary to modify the behind-the-ear module at all.

Direct sound is sound passing through a vent passage and/or through other acoustic leakages of or around a hearing

P208727 system ear-piece or ear-cap. For cancelling direct sound a configuration as depicted by subsystem 12 13 and/or 14 is suited. Direct sound cancellation is especially beneficial if the signal to be presented acoustically to the hearing system user does not directly correspond to the amplified environment sound. This is, for example, the case if the signal comes from a recording, such as an mp3 player, if the signal comes from a remote microphone, such as over a telephone network, as well as if the signal is a filtered or special version of the environment sound, such as in the case of a signal provided by a directional microphone. Cancellation of direct sound can also be used to enhance the passive acoustic seal provided by a hearing system earpiece and/or ear-cap, a concept which is often denoted by the term "active noise reduction" or ANR. A direct sound cancellation is described in more detail in US 6,920,227.

Own-voice is a sound emitted by the hearing system user. The own-voice, but also other body sounds, are perceived unnaturally loud when the ear-canal is blocked with an earpiece module. This is among other factors the cause for the so called occlusion effect. The occlusion effect can be reduced by cancelling own-voice in the space between the eardrum and an ear-piece module. For cancelling own-voice, a configuration, as depicted by subsystem 14, is suited. An active own-voice cancellation is described in more detail in US 6, 937,738.

Feedback is an artefact resulting from sound leakage from a loudspeaker, such as receiver 6, to an environment sound

P208727 microphone, such as the microphone of environment microphone subsystem 7. Feedback is especially a problem if the aperture of a vent passage, such as vent passage 31, was chosen large to counteract the occlusion effect. For feedback cancelling, a configuration as depicted by subsystem 13 is suited. An active feedback cancellation is described in more detail in DE 40 10 372 C2.

Besides of the components and subsystems illustrated in the Fig. 2, any kind of electrically powered component in the ear-piece module 2 may be powered by said power supply means 16, in particular:

- Any kind of sensor, such as an acoustic sensor, in particular a voltage or current biased microphone with or without amplifier, a pressure sensor, a temperature sensor, an optical sensor, in particular a camera, a position sensor, in particular a GPS receiver, an acceleration sensor and/or a user input sensor, in particular a potentiometer, an up/down or an on/off switch,

- Any kind of actor, in particular an additional loudspeaker, a drive, in particular an electric motor or an electromagnet, a display, informative or decorative lights,

- Any kind of circuit, in particular an amplifier, a decoder, an analogue/digital converter, a digital/analogue converter,

P208727 - Any kind of processor, in particular a controller or a digital signal processor.

In a further embodiment, all electrically powered components of the ear-piece module 2 are powered by said power supply means 16 which generates a supply voltage from said receiver signal. This has the advantage that connection 4 does not need to comprise electrical power lines in addition to the electrical signal lines, which makes it less conspicuous, less costly and less complex, and the user of the hearing system has to replace and/or recharge only one battery, namely a primary battery located in said not shown further module. As far as voltage and current are below applicable legal limits one of the electrical lines of connection 4 may be omitted by using the body as an electrical conductor.

The term "subsystem" is used to denote a set of components which serve together for a particular purpose. Components may be shared between the subsystems. In particular, the receiver 6 may be used jointly by different sound cancellation subsystems and, in the case of a hearing aid, the main environment sound amplification subsystem. A sharing of a receiver by different subsystems can be implemented in various ways. For example a special receiver can be used which has two separate coils or coil portions, the subsystems may be initially galvanically separated such that an adding of the signals can be done by a serial connection or the two voltages may simply be merged by

P208727 connecting both amplifier outputs to the same receiver input .

Fig. 3 shows a schematic diagram of a behind-the-ear module 1 and of an ear-piece module 2 of a hearing system according to an embodiment of the invention. A behind-the- ear microphone 21 picks up an environment sound. In case of a hearing system used to compensate a hearing loss, sound signal processor 22 processes the signal in order to compensate the particular hearing loss of the user of the hearing system. The processed signal is amplified by an amplifier 5 which preferably provides a pulse width or pulse density modulated signal and which comprises an H- bridge 23 as output stage. A connection 4 between the two modules 1 and 2 comprises two wires or electrical conductors for transmitting receiver signal U _R , namely a receiver signal line 24 and a reference potential line 25. The wires connect the output of the H-bridge 23 with the input of a receiver 6. The ear-piece module 2 comprises a power supply means 16. A bridge rectifier 17 converts the receiver signal U _R which is more or less an alternating current (AC) into a direct current (DC) supply voltage U ₃ . The supply voltage is stabilized by a capacitor 18 and/or a rechargeable battery 20, which may be termed intermediate battery due to its functional location. The functioning of the receiver 6 should not be compromised by power supply means 16. Therefore, the power supply means 16 preferably has a higher or substantially higher input impedance than the receiver 6. The components, which are powered by supply voltage U ₃ , are not shown and are, for example, any of the

P208727 ones described referring to Fig. 2. In some cases, in regard to power supply means 16, a high power output might be needed, but only occasionally and for a short time. Under these circumstances, it can be advantageous to use a capacitor 18 and/or rechargeable battery 20 which is sufficiently large to buffer such changes in power output requirement, which is described in more detail further down below in connection with Fig. 5. The hearing system can preferably be operated fully battery powered, i.e. all electric energy used in the hearing system originally comes from a battery, not shown in Fig.3, in particular the primary energy storage means or primary battery in a behind-the-ear module 1, as for example battery 3 shown in Fig. 1. The hearing system may also be "wireless" in the sense that it can be operated without any wires to components not worn at and/or in the body or the head of the user. The primary battery is preferably configured to be replaced and/or recharged conveniently by the user of the hearing system as part of its everyday operation.

Fig. 4 shows a schematic diagram of an ear-piece module 2 of a hearing system according to an embodiment of the present invention. The ear-piece module 2 comprises a microphone subsystem 8 with a canal microphone 26. A part of a behind-the-ear module 1 and a connection 4 between the behind-the-ear module 1 and the ear-piece module 2 are also shown. The connection 4 comprises three wires, namely a receiver signal line 24, a microphone signal line 28 and a reference potential line 25. The receiver signal line 24 serves for transmitting the receiver signal U _R . The

P208727 microphone signal line 28 serves for transmitting the microphone signal U _M provided by the microphone subsystem 8. The reference potential line 24 is shared between the two signals. However, the microphone signal U _M might also be used only internally in the ear-piece module 2 such that only two wires are necessary for the connection 4. The microphone 26 may be used in a current biasing mode, being connected to the remaining circuit of the ear-piece module 2 by two lines, or it may be used in a voltage biasing mode, being connected to the remaining circuit of the earpiece module 2 by three lines. A supply voltage U ₅ for the microphone subsystem 8 is provided by a power supply means 16. The power supply means 16 comprise a half-wave rectifier 19 (a diode) and a capacitor 18 for smoothing. A half-wave rectifier has the advantage that the output voltage has the same reference potential or ground voltage as the input voltage.

The bridge-rectifier of Fig. 3 has the disadvantage of providing a supply voltage Us with a different reference potential than the receiver signal U _R . The half-wave rectifier of Fig. 4 provides a supply voltage U ₃ having the same reference potential as the receiver signal U _R , but uses only half of the available receiver signal U _R . To overcome these disadvantages a power supply means in an ear-piece module may also be equipped with a transformer. A receiver signal U _R is fed to the input of the transformer. At the output of the transformer, there is an alternating voltage which is galvanically isolated from the receiver signal U _R . This alternating voltage can be rectified using

P208727 a bridge rectifier of the kind shown in Fig. 3 to produce a supply voltage U _s between two rectifier output lines. Due to the galvanic isolation one of the rectifier output lines can be connected to the same common reference potential as is used for the receiver signal U _R . Such a solution with a transformer has further the advantage that it opens up the possibility to generate a supply voltage U ₃ which has a higher magnitude than the receiver signal U _R . Alternatively a higher magnitude may be obtained by a DC/DC converter.

Fig. 5 shows a schematic diagram of an ear-piece module 2 of a hearing system according to an embodiment of the invention. The ear-piece module 2 comprises a vent valve drive subsystem 11 which can be used to mechanically open and close a vent passage in the ear-piece module 2, such as vent passage 31 shown in fig. 2. It is desirable to keep the vent open as much as possible, since a closed vent increases the occlusion effect and also leads to undesirable moisture in the ear canal. However, in noisy environments, for example in the case of a hearing aid being used in a directional microphone mode, the vent passage should be closed to keep noise or so called direct sound from entering the ear canal. In the ear-piece module 2, a supply voltage U ₅ is generated from the receiver signal U _R . A decoder 30 is provided as a drive control circuit. It detects commands such as "open vent passage" or "close vent passage" which are superposed or integrated in the receiver signal U _R and generates a corresponding drive signal U _D to make a mechanical drive 29 open or close the vent passage. Power supply means 16 preferably comprise an

P208727 intermediate energy storage means or buffer, as for example battery 20 shown in Fig. 3, which is large enough to store the energy needed to fully open and close the vent passage at least once or at least five times. In a further embodiment, the intermediate energy storage means has a capacity which is between 0.1% and 10% of the capacity of the primary energy storage means in a first module 1. Energy taken from the receiver signal U _R is accumulated in said intermediate energy storage means. This has the advantage that only very low power, i.e. energy per time, needs to be taken from the receiver signal U _R , but nevertheless high power can be provided occasionally, for example when the vent passage is to be closed or opened. Accumulating power for one full vent passage opening or closing may take between one minute and half an hour, for example .

The principles described referring to the vent valve drive subsystem 11 can also be applied to other drive subsystems, for example one configured for actuating a directional microphone.

The principle of accumulating power from a receiver signal for occasional high power demand described in connection with the vent valve drive system 11 can also be applied to other subsystems, for example a sound cancellation system which is designed for cancelling sounds with relatively rare occurrence, such as, depending on the hearing system user, own-voice in calm situations.

P208727 Figs. 6 to 9 each show a signal diagram of a pulse width modulated receiver signal U _R and the resulting receiver membrane displacement d _R in dependence on time t. Such signal characteristics may, for example, occur in the hearing system shown in Fig. 3. A pulse-width or density modulated receiver signal U _R is especially well suited for a power supply means which takes power from a receiver signal U _R since there is always a voltage, in particular an alternating voltage, even if the receiver is silent. The voltage provided by the hearing system amplifier output stage can be used directly without the necessity to add a direct current voltage. Fig. 6 shows the case where a sine wave is presented to the ear. Figs. 7, 8 and 9 each show a case where the receiver is silent. Fig. 7 shows the case with a positive static receiver membrane displacement d _R ,

Fig. 8 the case with a negative static displacement d _R and Fig. 9 the case without displacement. Hence, there are three different kinds of characteristics of the receiver signal U _R which are all perceived by the individual wearing the hearing system as silent but may still be carrying power. This effect can, for example, be used to encode control commands for a vent valve drive as described in connection with Fig. 5. A receiver signal U _R resulting in a positive static displacement d _R for a certain time, as shown in Fig. 7, could be an "open vent passage" command and accordingly a receiver signal U _R resulting in a negative static displacement d _R , as shown in Fig. 8, could be a "close vent passage" command. Such a solution has the advantage of a low complexity since the low-pass filtered receiver signal U _R corresponds directly to the voltage

P208727 which has to be applied to a direct current vent valve motor.

In a more basic embodiment, the receiver signal U _R might not be pulse-width modulated but reflect directly the desired membrane displacement d _R . Power transmission during times when the receiver is to be silent can be achieved by adding a direct current component to the signal which results in static membrane displacements d _R such as the ones shown in Figs. 7 and 8.

Generally, referring to all of the above described examples, there is a first module which provides a receiver signal and a second module which comprises a power supply which generates a supply voltage or current based on power taken from said receiver signal. In most of the examples, said first module is a behind-the-ear module and said second module is an ear-piece module, which may also be termed "in-the-ear module". However, the concept of the invention can be applied to other module configurations. In particular, the first module might be a module to be worn in the pinna (concha) , while the second module is an earpiece module worn fully or partially in the ear canal. Further, the first module might be a pocket module while the second module is an ear-piece or behind-the ear module.

A connection between the modules can be fixed, can be detachable from one module, and can be detachable from both modules. A detachable connection has the advantage that, in case of a malfunction, only one module might have to be

P208727 exchanged such that the cost and time for repairing is reduced. Further, different modules can be combined outside of the factory, for example by the user or by an audiologist. A connection which is detachable from both modules has the advantage that different lengths of connections can be provided in a convenient way. Further, the avoidance of a separate power supply line is especially advantageous in the case of detachable module connectors because one of the expensive and/or conspicuous connector plugs or pins is avoided as well.

The use of the term "module" in the present document is not meant to imply that there are necessarily more modules or configurations of modules than the described first and second module. However, in a particular embodiment, there can, for example, be provided a kit of hearing system parts comprising several different behind-the-ear modules and several different ear-piece modules which can be combined in various ways. In case of a hearing aid the combination can be done by an audiologist during fitting to optimally suit a patients hearing loss, anatomy of the ear and/or personal preferences. For example a patient may be provided initially with a receiver-only ear-piece module. Later, if the patient reports problems with occlusion, it may be replaced by an occlusion cancelling ear-piece module.

As already mentioned at the outset, the features described referring to the figures in an exemplary way may be employed, isolated or in various combinations, in hearing

P208727 aids, hearing protectors, communication systems and headsets.

A hearing aid will usually be designed to compensate for a hearing loss of an individual and comprise an environment sound microphone for picking up sounds from an environment of the individual, fitting parameters stored in a non volatile memory by an adjustment of which a behaviour of the hearing system is configurable in such a way that at least part of said hearing loss can be compensated and a fitting interface configured to allow adjustment of said fitting parameters by said individual and/or by a hearing health care professional. The fitting interface may be wired or wireless and provide an interface to a fitting device, in particular a PC with fitting software.

A hearing protector protects the hearing of an individual from loud environment noises, as for examples ear plugs or ear muffs. The invention is applicable to active protectors being active in the sense that they comprise a receiver or a loudspeaker. For example, if an active noise reduction ear muff is to be enhanced by an active vent valve, the vent valve drive subsystem may be powered as in the above described examples.

A communication system is a system which allows communication between individuals, as for example a telephone system. A communication system may comprise an ear-piece module with a receiver or loudspeaker for presenting the voice of a remote individual to the

P208727 individual wearing the ear-piece module. Such an ear-piece module may be enhanced with a subsystem, such as an vent valve drive subsystem, which is powered as in the above described examples.

A headset is a device at least partially worn at the head of an individual which is configured to deliver and/or pick up sound at the head of an individual. A headset may be part of a communication system. Typical examples of headsets are:

- earphones comprising at last one loudspeaker, which earphones may be suitable for listening to various sound sources such as radio broadcasting or recordings

- handsfree sets for telephones comprising at least a loudspeaker and a microphone, which handsfree sets may be suitable for telephoning during other activities such as typewriting or driving. For example, the microphone of such a handsfree set may be powered as in the above described examples.

A hearing system module "worn at the head of an individual" will usually physically contact the head, but may also be affixed in close proximity of the head, in particular closer than 1 cm. It may be affixed utilizing the physical shape characteristics of the head. For example it may be inserted in the ear canal or positioned behind the concha. It may also be affixed by some kind of carrying structure as for example a helmet.

P208727 A hearing system module which is "body-worn" is worn at and/or in the body of an individual. It may be, as described above, a module worn at the head, which includes partial or full insertion in the ear-canal, but may also be designed to be affixed to the body in an other way and/or place, for example on a belt, in a pocket or it may simply be handheld. It may also be fully or partially implanted.

List of Reference Symbols

1 behind-the-ear module

2 ear-piece module

3 battery 4 connection

5 amplifier

6 receiver

7 environment microphone subsystem

8 canal microphone subsystem 9 vent microphone subsystem

10 vent loudspeaker subsystem

11 vent valve drive subsystem

12 first cancellation subsystem

13 second cancellation subsystem 14 third cancellation subsystem

16 power supply means

17 bridge rectifier

18 capacitor 19 half-wave rectifier

P208727 20 rechargeable battery

21 behind-the-ear microphone

22 signal processor

23 H-bridge 24 receiver signal line

25 reference potential line

26 in-the-ear microphone

27 microphone amplifier

28 microphone signal line 29 mechanical drive

30 decoder

31 vent passage

32 ear canal

U _R receiver signal

U ₃ supply voltage

U _M microphone signal

U _D drive signal d _R membrane displacement

P208727