NL2009348C2

NL2009348C2 - Audio listening device and method of audio playback.

Info

Publication number: NL2009348C2
Application number: NL2009348A
Authority: NL
Inventors: Engbert Wilmink
Original assignee: Dynamic Ear Company B V
Priority date: 2012-08-23
Filing date: 2012-08-23
Publication date: 2014-02-25
Also published as: WO2014030998A1

Abstract

There is provided an audio listening device comprising a housing, shaped to substantially form a pressure seal between an auditory canal of an ear and an external surroundings. A pressure relay channel in the housing is arranged for relaying a pressure difference between the auditory canal and the external surroundings. A pressure valve in the pressure relay channel is arranged for switching between an open or closed position for allowing or preventing, respectively, an exchange of pressure. An acoustic generator between the pressure valve and the auditory canal is arranged for generating an acoustic signal into the auditory canal. A pressure sensor is arranged for measuring an internal pressure level in the auditory canal and control logic is arranged for controlling an actuator to switch the pressure valve to an open position when the measured internal pressure level is above a threshold pressure level.

Description

Title: AUDIO LISTENING DEVICE AND METHOD OF AUDIO

PLAYBACK

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to an audio listening device and a method of audio playback.

Current use of mobile audio listening devices like MP3 players is 5 leading to an increasing number of youngsters becoming (partially) deaf. When listening to music or other sounds in a noisy environment the tendency is to increase the volume of a music player to be able to surpass the surrounding ambient noise and enjoy the private music source.

One way to attenuate external noise levels is to use an ear plug for 10 partially or wholly sealing the ear channel from the environment. Sealing of the ears may be advantageous e.g. for the proper use of modern so called balanced armature receivers, which may deliver a hi-fi performance for the user. However, continuous sealing of the ear may not be desired, e.g. in different acoustic environments.

15 International application WO 2007/097627 by the present inventors, discloses an earplug with playback capabilities that also provides an option for hearing ambient sound. Through the provision of the device according to WO 2007/097627, with which a regulating device regulates the level of damping depending on detection of control signals to the 20 loudspeaker, in particular, an earplug is disclosed with which, when he is not listening to music, the user can observe the ambient sounds without having to remove the earplug from his ear. According to WO 2007/097627, various means are suitable for transmitting the ambient sound to the ear canal of the user, e.g. by electronic transmission, though preferably by an 25 adjustable acoustic valve.

There is yet a need for an audio listening device and a method of audio playback that provides further prevention of damage and/or discomfort for the user.

2

SUMMARY OF THE INVENTION

In a first aspect there is provided an audio listening device comprising a housing, shaped to substantially form a pressure seal between an auditory canal of an ear and an external surroundings. The housing 5 comprises a pressure relay, a pressure valve, an acoustic generator, and a valve control. The pressure relay channel extends through the housing between the auditory canal and the external surroundings. The pressure relay channel is arranged for relaying a pressure difference between the auditory canal and the external surroundings. The pressure valve is 10 arranged in the pressure relay channel and arranged for switching between an open or closed position for allowing or preventing, respectively, an exchange of pressure between the auditory canal and the external surroundings. The acoustic generator is arranged between the pressure valve and the auditory canal and arranged for generating an acoustic signal 15 into the auditory canal. The valve control comprises an actuator, control logic and a pressure sensor. The actuator is arranged for switching the valve between the open and closed positions. The control logic is arranged for controlling the actuator. The pressure sensor is arranged for measuring an internal pressure level in the auditory canal. In particular, the control logic 20 is arranged for controlling the actuator to switch the pressure valve to an open position when the measured internal pressure level is above a threshold pressure level.

The inventors recognized that when sealing the ears using conventional audio listening devices, it is easy to exceed the sound pressure 25 in the ears above levels that are considered safe for short or long exposures. By providing a pressure sensor for measuring the internal pressure in the auditory canal and opening the pressure valve when the measured internal pressure exceeds a pressure threshold, damage and/or discomfort due to over- or under pressure in the ear canal can be prevented. Different from 30 WO 2007/097627, the currently proposed audio listening device comprises 3 an internal pressure sensor and control logic that is arranged to open the acoustic valve in response to a measured internal pressure level in the ear canal. While conventional ear plugs are used to seal the ear against external noise levels, the currently proposed audio listening device provides 5 protection against excessive internal pressure levels.

The ear drum (tympanic membrane) separates the auditory canal of the outer ear (external acoustic meatus) from the middle ear (tympanic cavity). While the middle ear may have a pressure equal to that of the external surroundings by passing air via the Eustachian tubes, the 10 inventors recognized that the pressure in the outer ear may no longer be equilibrated with the external surroundings when the ear is sealed, e.g. by a conventional audio listening device. As a result, a pressure difference between the outer ear and the middle ear may cause a net pressure on the ear drum that may be uncomfortable or damaging to a user of such an audio 15 listening device.

Accordingly, in an embodiment, the pressure sensor is further arranged for measuring an external pressure level of the external surroundings wherein the internal pressure level is measured relative to the external pressure. The control logic is arranged for controlling the actuator 20 to open the pressure valve when a pressure difference between the internal and external pressure levels is higher than a threshold pressure difference.

Besides relieving a pressure difference, e.g. as a result of a sound pressure caused by the acoustic generator, the opening of the pressure valve may also be advantageous for equalizing the pressure between the outer and 25 middle ear in environments with varying pressures, e.g. in airplanes or scuba diving. It is currently recognized that in such varying pressure environments, an uncomfortable and potentially damaging pressure difference may occur between the inner and outer ear when the outer ear is sealed from the external surroundings. The currently proposed audio 30 listening device may thus be advantageous e.g. for users wishing to listen to 4 audio while traveling by airplane. Advantageously, the currently proposed audio listening device may attenuate the ambient noise, e.g. from the airplane, and may equilibrate excess pressure differences, e.g. caused by pressure differences during landing and take-off.

5 In a second aspect there is provided a method for controlling an audio listening device comprising a housing, shaped to substantially form a pressure seal between an auditory canal of an ear and an external surroundings; the housing comprising: a pressure relay channel extending through the housing between the auditory canal and the external 10 surroundings arranged for relaying a pressure difference there between; a pressure valve arranged in the pressure relay channel, the pressure valve arranged for switching between an open or closed position for allowing or preventing, respectively, an exchange of pressure between the auditory canal and the external surroundings; an acoustic generator arranged 15 between the pressure valve and the auditory canal; the method comprising generating an acoustic signal into the auditory canal using the acoustic generator; measuring an internal pressure level in the auditory canal; and controlling a switching of the pressure valve wherein the pressure valve is switched to an open position when the measured internal pressure level is 20 above a threshold pressure level.

The method according to the second aspect may provide a user with the benefits of sealing the ear while listening to audio playback, e.g. an improved cancellation of ambient noises, while at the same time providing the user with a measure of protection against excessive pressures in the 25 auditory canal which may otherwise cause discomfort and/or damage to the user’s ear. A method according to the second aspect may e.g. be provided by an audio listening device according to the first aspect.

5

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawing 5 wherein: FIG 1 shows a schematic first embodiment of an audio listening device according to the first aspect.

FIG 2 shows a schematic second embodiment of an audio listening device comprising a differential pressure sensor.

10 FIG 3 shows a schematic third embodiment of an audio listening device comprising a pressure sensor with microphones.

FIG 4 shows a schematic fourth embodiment that is a combination of the second and third embodiments.

FIG 5 shows a schematic fifth embodiment similar to the fourth 15 embodiment but comprising a second pressure valve.

FIG 6 shows a schematic first embodiment of a housing for an audio listening device.

FIG 7 shows a schematic second embodiment of a housing for an audio listening device.

20 FIG 8 shows a schematic third embodiment of a housing for an audio listening device.

FIG 9 shows a graph comparing sound pressure levels between an open and closed valve.

25 DETAILED DESCRIPTION

The following detailed description of certain exemplary embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. The description is therefore not to be taken in a limiting sense, and the scope of the present system is defined 30 only by the appended claims. In the description, reference is made to the 6 accompanying drawings which form a part hereof, and in which are shown by way of schematic illustration specific embodiments in which the described devices and methods may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the 5 presently disclosed systems and methods, and it is to be understood that other embodiments may be utilized and that structural and logical changes may be made without departing from the spirit and scope of the present system. Moreover, for the purpose of clarity, detailed descriptions of well-known devices and methods are omitted so as not to obscure the description 10 of the present system.

It is recognized that while most receivers are to be used at medium sound pressure levels to avoid distortion, it may not be desired to use lower dB producing receivers as the sound quality may become unacceptable to the experienced hi-fi requiring user. Furthermore, the human ear is 15 generally less sensitive for low frequency sounds between 20-200 Hz. An average listener may for example experience a possibly harmful sound of 100 dB at 50 Hz equally as loud as if it were only 80 dB at 1000 Hz. Therefore, one may need to be careful when playing low frequency sound on high sound levels in a sealed ear.

20 The inventors have found that a sound pressure level (SPL) in an ear can be reduced in case it becomes too high by usage of a pressure valve in an otherwise pressure sealed earplug or earphones. The device may keep the orifice closed under safe usage conditions of a sealed headset and, in case the sound pressure in the ear becomes too high, the orifice may be 25 opened. It was found that by opening an orifice of suitable size the sound pressure in the ear can be conveniently and effectively reduced to a safer level thus generating a safer headset that can be used with a variety of sound sources. It is noted that an acoustic valve was previously disclosed e.g. in international patent publications WO 2005/041831 and WO 30 2007/097627 by the present inventors, for attenuating external noise levels.

7

Further advantages and applications may become more apparent from the following detailed description of the drawings. This description again is to be regarded in an illustrative and non-limiting manner. In particular, steps and/or parts of the shown embodiments may be omitted 5 and/or added without departing from the scope of the current methods and systems, which scope is defined by the appended claims. Unless stated otherwise, like reference numerals refer to like elements throughout the drawings.

FIG 1 shows a first embodiment of an audio listening device 1. The 10 audio listening device 1 comprises a housing 2, shaped to substantially form a pressure seal between an auditory canal 11 of an ear and an external surroundings 12. See also FIG 6-8. The housing 2 comprises a pressure relay channel 3 extending through the housing 2 between the auditory canal 11 and the external surroundings 12 arranged for relaying a pressure 15 difference there between. A pressure valve 4 in the pressure relay channel 3 is arranged for switching between an open or closed position for allowing or preventing, respectively, an exchange of pressure between the auditory canal 11 and the external surroundings 12. An acoustic generator 9 between the pressure valve 4 and the auditory canal 11 is arranged for generating an 20 acoustic signal into the auditory canal 11.

The pressure valve 4 is controlled by a valve control comprising an actuator 5 arranged for switching the valve between the open and closed position and control logic 6 arranged for controlling the actuator 5. The control logic receives input from a pressure sensor 7, arranged for 25 measuring an internal pressure level PI in the auditory canal 11. The control logic 6 is arranged for controlling the actuator 5 to switch the pressure valve 4 to an open position when the measured internal pressure level PI is above a threshold pressure level. In this way an excess pressure in the auditory canal may be prevented.

8

In a further embodiment the control logic 6 may be arranged for controlling the actuator 5 to switch the pressure valve 4 to a closed position when the measured internal pressure level PI is below said threshold pressure level or below a lower pressure threshold. In this way an improved 5 cancellation of ambient noises may be achieved when there is no excess pressure in the auditory canal.

It is currently recognized by the inventors that the internal pressure level PI may be influenced not only by ambient pressure fluctuations but also e.g. by an internal sound pressure level Si caused by 10 sound waves emitted from the acoustic generator 9. The term “sound pressure” refers to a local pressure deviation from the average or equilibrium pressure caused by a sound wave. The term “sound pressure level” refers e.g. to a logarithmic measure of the effective sound pressure of a sound relative to a reference value. It may be measured e.g. in decibels 15 (dB) above a standard reference level, e.g. 20 pPa root mean square in air or 1 pPa under water. These and other reference levels may be defined e.g. in a standard such as ANSI Si. 1-1994. It is thus to be appreciated that the measured internal pressure level may be a function of the internal sound pressure level in the auditory canal, e.g. the internal pressure level may 20 increase proportionally with the internal sound pressure level.

In an embodiment, the pressure sensor 7 comprises a microphone arranged for measuring a sound pressure level (SPL). Sound waves registered by the microphone may be converted into electrical signals that are inputted into the control logic of the valve control. The control logic may 25 convert these signals into corresponding pressure levels and control the pressure valve via the actuator according to the above specifications. An advantage of using a microphone may be a quick response time to varying SPL in an audio signal.

In the shown embodiment, part of the pressure relay channel 3b 30 may be cylindrical and sealed at an end by the pressure valve 4.

9

In an embodiment the acoustic generator comprises an electroacoustic transducer, e.g. an audio speaker, electrically connected to a frequency and/or amplitude modulated electric source that is comprised in a playback device, e.g. a music player. In a further embodiment the valve 5 control may be also arranged for opening the pressure valve in the pressure relay channel as a function of an electric signal received from the electric source. In this way a quicker response to fluctuations of a sound pressure level caused by sound waves generated by the acoustic generator may be achieved.

10 In an embodiment, the acoustic generator 9 comprises a balanced armature receiver. Advantageously, this may e.g. further increase electrical efficiency of the acoustic generator 9 and allow for a HiFi experience for the user at relatively low SPL.

The actuator 5 may be e.g. electromechanically driven and/or 15 comprise a piezo crystal. This may have an advantage that the actuator can be durable, energy efficient and quite small, e.g. small enough to fit into an ear bud.

It is to be appreciated that the threshold pressure level may be defined as an absolute pressure level or a pressure level difference. For 20 example, the threshold pressure level may be set at an absolute pressure value, e.g. 101.8 kPa (i.e. 0.5 kPa over the standard atmospheric pressure of 101.3 kPa), wherein the pressure valve opens when the measured pressure exceeds this (absolute) pressure value. Alternatively the pressure threshold may be set relative to an external pressure level, e.g. the threshold pressure 25 level may be set at 0.5 kPa above or below the external pressure level, wherein the pressure valve opens when the pressure difference exceeds this value. Alternatively still, the threshold pressure level may be set in terms of a sound pressure level e.g. of 85 dB, wherein the pressure valve opens when the internal sound pressure level in the ear exceeds this value. Alternatively 30 still the threshold pressure level may be defined as a sound pressure level 10 difference of 5 dB, e.g. wherein the pressure valve opens when the sound pressure level in the ear is at least 5 dB higher than that of the external surroundings. Also combinations of the above threshold pressure levels may be used, e.g. the pressure valve may open when the absolute pressure 5 exceeds 101.8 kPa or exceeds the external pressure by more than 0.5 kPa.

FIG 2 shows a second embodiment of an audio listening device 1 according to the first aspect. In this embodiment, the device 1 comprises a differential pressure sensor 7ab. The pressure sensor 7ab is arranged for 10 measuring both the internal pressure PI in the auditory canal 11 and an external pressure level P2 of the external surroundings 12. The threshold pressure level is now a function of the measured external pressure level P2 such that the control logic 6 is arranged for controlling the actuator 5 to open the pressure valve 4 when a pressure difference ΔΡ = | PI — P21 15 between the internal and external pressure levels is higher than a threshold pressure difference.

By measuring the pressure difference between the outside and the inside of the ear, the pressure valve 4 can be used to equalize the pressure in the ear by subtly opening the valve 4. The pressure (difference) could e.g. 20 be measured by using MEMS pressure sensors which are able to measure small changes in pressure differences (e.g. 2 pa / 100 ms). For example, suitable sensors are available commercially as the Alps HSPPAR or HSSPARC, or the Bosch BMP180 and Acuity AC3050 (differential). Some of these pressure sensors may be also suitable for measuring high amplitude 25 94 (dB) low-frequent (< 200 Hz) sound pressure levels.

For example, passengers of airplanes may experience unwanted pressure differences between the inner/middle ear and the outer ear during take off and landing e.g. pressure differences of up to 30 kPa. When the passenger does not clear his ears, e.g. by swallowing or using chewing gum, 30 pressure difference can lead to a sharp pain in the ear or a headache. A

11 related subject is the clearing of divers when going to another water depth. To prevent a big pressure difference over the eardrum that can easily damage it, divers should actively equalize the pressure in the ear.

It is to be appreciated that under normal circumstances a pressure 5 level in the middle ear may be equilibrated with the external pressure level P2 via the Eustachian tubes. When a user of an audio listening device seals his ears, e.g. by a housing 2 that forms a pressure seal between the auditory canal, i.e. the outer ear, and the external surroundings, a pressure difference may occur between the outer ear and the middle ear. This 10 pressure difference ΔΡ may be felt by the user as an uncomfortable pressure on his eardrum that separates the outer and middle ear. Thus by comparing the internal pressure PI to the external pressure P2, e.g. using a differential pressure sensor, a good measure may be obtained of the pressure felt by the user. It is noted that these pressure differences may be either positive or 15 negative, i.e. P1>P2 or P1<P2. Either pressure difference may be experienced as uncomfortable by the user.

The total pressure in the auditory canal 11 may be a sum or other combination of a static pressure level PI, e.g. influenced by the environment and a sound pressure level Si, e.g. influenced by sound waves, either 20 external or produced by the acoustic generator 9.

In an embodiment similar to the embodiment shown in FIG 2, but wherein the acoustic generator 9 does not produce sound waves or wherein the acoustic generator 9 is altogether absent, there may be provided a noise cancelling earplug device comprising a housing 2, shaped to substantially 25 form a pressure seal between an auditory canal 11 of an ear and an external surroundings 12; the housing 2 comprising a pressure relay channel 3 extending through the housing 2 between the auditory canal 11 and the external surroundings 12 arranged for relaying a pressure difference there between; a pressure valve 4 arranged in the pressure relay channel 3, the 30 pressure valve 4 arranged for switching between an open or closed position 12

for allowing or preventing, respectively, an exchange of pressure between the auditory canal 11 and the external surroundings 12; and a valve control comprising an actuator 5 arranged for switching the valve between the open and closed position; and control logic 6 arranged for controlling the actuator 5 5; a pressure sensor 7, arranged for measuring an internal pressure level PI

in the auditory canal 11; wherein the control logic 6 is arranged for controlling the actuator 5 to switch the pressure valve 4 to an open position when the measured internal pressure level PI is above a threshold pressure level. In a further or alternative embodiment the pressure sensor 7 of the 10 said ear plug device is arranged for measuring also an external pressure level P2 of the external surroundings 12; and the threshold pressure level is a function of the measured external pressure level P2 such that the control logic 6 is arranged for controlling the actuator 5 to open the pressure valve 4 when a pressure difference ΔΡ between the internal and external pressure 15 levels is higher than a threshold pressure difference. For example, the pressure sensor of the earplug device may comprise a differential pressure sensor 7ab as shown.

Advantageously, such an earplug device may provide the benefit of attenuating external noise while at the same time providing the user with a 20 measure of protection against excessive pressures in the auditory canal which may otherwise cause discomfort and/or damage to the user’s ear. An application of such an earplug device may be e.g. for passengers of an airplane. In particular, the passenger may use the earplug to attenuate noise from the airplane and/or the other passengers while not having to 25 worry about excessive pressures on his ear drum as a result of ambient pressure fluctuations, e.g. during landing and take-off. Another application may be for musicians, e.g. playing trumpet, horn, woodwind etc. that may experience undesired pressure buildup in the ear when wearing conventional hearing protection.

30 13 FIG 3 shows a third embodiment of an audio listening device 1 wherein the pressure sensor comprises two microphones 7a and 7b. The microphone 7b of the pressure sensor is arranged for measuring an internal sound pressure level Si in the auditory canal 11. The microphone 7b of the 5 pressure sensor is arranged for measuring an external sound pressure level S2 of the external surroundings 12. In an embodiment a threshold sound pressure level at which the pressure valve 4 is opened is a function of the measured external sound pressure level S2 such that the control logic 6 is arranged for controlling the actuator 5 to open the pressure valve 4 when a 10 sound pressure difference AS = Si - S2 between the internal and external sound pressure levels is higher than a threshold sound pressure difference.

In a further embodiment, the control logic is further arranged to close the pressure valve 4 or keep the pressure valve 4 closed when an external sound pressure level S2 exceeds an threshold sound pressure level 15 value that may otherwise cause damage or discomfort to a user, e.g. a value of 85 dB or more.

In an embodiment the pressure sensor may comprise a hydrophone for measuring an SPL under water. Such an embodiment may e.g. be used for an underwater audio listening device.

20 In an embodiment, the pressure sensor and/or the control logic are arranged for time-averaging the measured pressures, e.g. over a time interval of 0.1 seconds or longer. It is to be appreciated that the time-averaged pressure, rather than e.g. the instantaneous pressure oscillations of impinging sound waves, may be indicative of the effective pressure felt by 25 a user on his ear drum. This embodiment may be combined e.g. with a sensor comprising a microphone or hydrophone FIG 4 shows a fourth embodiment of an audio listening device 1. The audio listening device 1 comprises a differential pressure sensor 7ab 30 arranged for measuring a pressure difference between a pressure level PI in 14 an auditory canal 11, and a level pressure P2 of an external surroundings 12. The audio listening device further comprises a microphones 7a for measuring an internal sound pressure level Si in the auditory canal 11 and a microphone 7b for measuring an external sound pressure level S2 from the 5 external surroundings 12. The audio listening device 1 comprises a pressure valve 4 and actuator 5 as discussed above. The control logic 6 comprised in the audio listening device 1 is arranged for receiving input from the differential pressure sensor 7ab and the microphones 7a and 7b. The control logic is further arranged to control the pressure valve 4 via the actuator 5 on 10 the basis of this input.

In an embodiment the pressure valve 4 is arranged for switching to intermediate cross-section openings between the open and closed positions thereby providing a variable cross-section opening in the pressure relay channel. In combination with such a variable cross-section pressure valve, 15 there is provided an embodiment wherein the control logic 6 is arranged to control the pressure valve 4 such that, depending on parameters and measured input values valve is switched between a slightly open position for a controlled equalization of a pressure difference; or a substantially or fully open position to decrease a sound pressure in the auditory canal; or a 20 substantially or fully closed position to enhance a sound quality and/or attenuate outside noise.

In an embodiment the control logic 6 controls the pressure valve 4 in accordance with parameters given in the following table: AS = S2 - SI SI (dB) IΔΡI = | P1-P21 Position Valve (dB) (kPa) >5 >85 <0.5 closed >5 >85 >0.5 slightly open >5 <85 <0.5 closed >5 <85 >0,5 slightly open <5 >85 <0.5 substantially open 15 <5 >85 >0.5 substantially open <5 <85 <0.5 closed <5 <85 >0.5 slightly open

For an embodiment with control logic operating according to the parameters of the above table, the pressure valve will not be substantially open when the external SPL is 5 dB or more above the internal SPL to 5 protect a user from the excessive external SPL. The valve may in that case only be slightly opened while a pressure level difference ΔΡ is more than 0.5 kPa to equilibrate the pressure Si in the auditory canal with the external pressure S2. When the external SPL is less than 5 dB above the internal SPL the pressure valve is kept substantially open while the SPL in the 10 auditory canal is above 85 dB, to reduce said internal SPL in the auditory canal. When the internal SPL is below 85 dB and the external SPL is less than 5 dB above the internal SPL, i.e. below 90 dB, the pressure valve may be kept closed when the pressure difference between the auditory canal and the external surroundings is below 0.5 kPa and slightly open when the 15 pressure difference is more than 0.5 kPa. In this latter mode the pressure valve is thus kept closed or slightly open to improve the audio quality experience of the user.

Accordingly, in an embodiment the control logic 6 is under the influence of control parameters, e.g. such as those given in the above table, 20 to choose between - reducing a maximum sound pressure level in the auditory canal when listening to sound generated by the acoustic generator by opening of the pressure valve to the external surroundings; - reducing undesired pressure differences between the auditory 25 canal and the external surroundings in a controlled way by providing a variable opening of the pressure valve; - enhancing a sound experience of the user by closing the pressure 16 valve; or - protecting the ear from external sound by closing the pressure valve.

The terms “substantially open”, “slightly open”, and “closed” may 5 refer e.g. to a cross-section opening of the pressure valve 4 of more than 0.2 mm2, between 0.05 mm2 and 0.2 mm2, and less than 0.05 mm2, respectively. Of course it is to be appreciated that the parameter values and/or the cross-sections stated here may be different depending on the desired level of protection.

10 The cross-section of the pressure valve 4 may be defined e.g. as the opening cross-section that is transverse to the airflow through the valve. Alternatively, the cross-section may be defined by the amount of air that runs through the pressure valve for a particular pressure difference over the pressure valve. Alternatively still the cross-section may be defined by the 15 rate of equilibration (e.g. in Pa/s) of the pressure difference (e.g. in Pa) over the pressure valve. This latter definition may be useful e.g. if it is desired that the rate of equilibration does not exceed a certain maximum equilibration rate.

Accordingly, in an embodiment, the control logic 6 is arranged to 20 control the pressure valve 4 such that the pressure difference ΔΡ between the internal and external pressure levels is equilibrated with a controlled rate of less than 50 Pa/s, preferably 25 Pa/s . This rate may be smaller than a maximum equilibration rate for a fully open pressure valve. Advantageously, in this way a sudden and uncontrolled pressure increase or 25 decrease in the auditory canal may be prevented. Such a sudden pressure change may otherwise be uncomfortable and/or damaging to a user. For example, with this embodiment, when pressure in an airplane suddenly drops from 100 kPa to 90 kPa is equilibrated over an equilibration time period of 10000/25 = 400 seconds. Similar advantages of a controlled 17 pressure difference equilibration rate may be experienced e.g. by divers that change depth.

FIG 5 shows a fifth embodiment of an audio listening device 1 5 similar to the fourth embodiment of FIG 4, but further comprising a second pressure valve 14 arranged between the acoustic generator 9 and the auditory canal 11. The second pressure valve 14 may switched by the control logic via a second actuator 15 between an open and closed position for allowing or preventing, respectively, an exchange of pressure between the 10 auditory canal 11 and the external surroundings 12. In an embodiment the control logic is arranged for controlling the second actuator 5 to switch the second pressure valve 14 to the closed position when a measured external sound pressure level S2 is above a specified threshold external sound pressure level threshold.

15 The second pressure valve 14 may operate in addition to the first pressure valve 4, wherein the first pressure valve 4 is opened when an internal sound pressure level Si exceeds an internal sound pressure level threshold. The opening of the first pressure valve 4 may result in a decrease of the SPL in the auditory canal that may result from sound waves 20 generated by the acoustic generator 9 while the closing of the second pressure valve 14 may result in a decrease of the SPL in the auditory canal that may be the result of external noise.

Such an embodiment may operate e.g. using a parameter table such as described above. In particular, in an embodiment the control logic 6 25 may be arranged for - reducing a maximum sound pressure level Si in the auditory canal when listening to sound generated by the acoustic generator 9 by opening of the first pressure valve 4 to the external surroundings; - reducing undesired pressure differences |ΔΡ| = |P1-P2| between 30 the auditory canal and the external surroundings in a controlled way by 18 providing a variable opening in both the pressure valves 4 and 14; - enhancing a sound experience of a user by closing the first pressure valve 4; or - protecting the ear from external (and internal) sound by closing 5 the second pressure valve 14.

Alternatively or in addition to some or all of the above functionality, the audio listening device may comprise a control override mechanism (not shown) arranged for overriding the control logic 6 and controlling the pressure valve 4 irrespective of input received from the 10 pressure sensor. This may have an advantage that a user may e.g. forcibly open the valve also in a noisy environment when he needs to hear the environment. Also the user may forcibly close the valve e.g. because he may expect a loud noise.

In an advantageous method of audio playback a user may use an 15 audio listening device such as disclosed in any of the above embodiment to seal the auditory canal 11 of his ear from the external surroundings 12, to generate an acoustic signal into the auditory canal 11, to measure an internal pressure level PI in the auditory canal 11, and to unseal the auditory canal 11 when the internal pressure level PI is above a threshold 20 pressure level.

Accordingly, in an embodiment there is provided a method for controlling an audio listening device 1 comprising a housing 2, shaped to substantially form a pressure seal between an auditory canal 11 of an ear and an external surroundings 12; the housing 2 comprising a pressure relay 25 channel 3 extending through the housing 2 between the auditory canal 11 and the external surroundings 12; a pressure valve 4 arranged in the pressure relay channel 3; and an acoustic generator 9 arranged between the pressure valve 4 and the auditory canal 11; the method comprises generating an acoustic signal into the auditory canal 11 using the acoustic 30 generator; measuring an internal pressure level PI,Si in the auditory canal 19 11; and switching the pressure valve between an open or closed position for allowing or preventing, respectively, an exchange of pressure between the auditory canal 11 and the external surroundings 12 through the pressure relay channel 3; wherein the pressure valve 4 is switched to an open 5 position when the measured internal pressure level PI,Si is above a threshold pressure level.

Of course the pressure valve 4 may be switched back to the closed position when the measured internal pressure level PI,Si gets below the threshold pressure level, e.g. for enhancing an audio listening experience.

10 In further method the internal pressure level PI may be measured in relation to an external pressure level P2 of the external surroundings and the auditory canal 11 is unsealed when a pressure difference between the internal and external pressure levels is higher than a threshold pressure difference.

15 In yet a further method the said pressure difference may be equilibrated with a controlled rate smaller than 100 Pa/s, preferably smaller than 50 Pa/s. An advantage of controlling the equilibration rate to be below this value is that this may provide an increased comfort to a user.

20 FIG 6 shows a first embodiment of a housing 2 for an audio listening device 1. The housing is shaped as an ear bud that can sealably fit at least partly into part of the auditory canal 11. As shown in the zoom-in view Z the housing 2 may have shape that is customized to the shape of the exterior part of an auditory canal 11 such that the housing may effectively 25 fit into the user’s ear 13. The housing may thus form a pressure seal between the auditory canal 11 and an external surroundings 12. The pressure seal may opened by opening the pressure valve 4 that is arranged in the relay channel 3 extending through the housing 2 between the auditory canal 11 and the external surroundings 12. By controlling the 30 pressure valve 4, and exchange of static pressure levels P1,P2 and sound 20 pressure levels Sl,S2 may be controlled. It is noted that while a particular configuration of the components comprised in the housing 2 is depicted here, the audio listening device may alternatively be arranged according to any of the described embodiments or variations thereof.

5 FIG 7 shows a second embodiment of a housing 2 for an audio listening device 1. The housing is again shaped as an ear bud that can sealably fit at least partly into part of the auditory canal 11. In the zoom-in view Z, it is illustrated that the housing 2 may be universal, i.e. adaptable to 10 fit in differently sized and shaped (exterior parts of) auditory canals 11.

Thereto the housing 2 may comprise e.g. a flexible material, able to adapt to the shape of an exterior part of the auditory canal 11 when inserted therein. Once inserted, the flexible material may expand to fill the said exterior part and form a pressure seal between the auditory canal 11 and the external 15 surroundings 12. The currently shown embodiment of a universal housing 2 comprises circumferential flexible ribs of increasing diameter. These ribs may decrease in diameter when inserted in the ear a fit against the walls of an exterior part of the auditory canal.

20 FIG 8 shows a third embodiment of a housing 2 for an audio listening device 1. In this embodiment the housing is not shaped as an ear bud such as in FIG 6 and FIG 7 but rather as (part of) a head phone. The housing 2 is shaped to form a barrier around the ear 13 separating the ear (and thus also the auditory canal 11) from the external surroundings 12. It 25 is noted that the pressure relay channel 3 in this and the previous embodiments may also extend to the exterior side 12.

In the shown embodiment, part of the pressure relay channel 3 may be cylindrical and sealed at an end by the pressure valve 4. An advantage of such a configuration may be that the cylinder acts as a valve 30 seat. The valve seat may be oriented such that when the valve is not 21 powered an over pressure in the auditory canal e.g. generated by an acoustic generator keeps the valve closed. Alternatively, the valve seat may be oriented such that an over pressure in the external surroundings may keep the valve closed when not powered. This may be advantageous e.g. when a 5 sudden pressure increase occurs in the external surroundings.

FIG 9 shows a comparison of measurements of internal sound pressure levels Si measured in an auditory canal 11 (see previous figures) of an ear produced by an audio listening device according to the first aspect.

10 The audio listening device was pressure sealed to the ear and comprised a pressure valve as described above. The solid curve 40 and the dashed curve 41 represent measurements using the device with a closed and opened pressure valve, respectively. Both curves measure the SPL in decibel (dB) at various frequencies F in Hertz (Hz). In the tested embodiment, the effect of 15 the pressure valve was the highest at the lower frequencies. This is also where a typical user may not be aware of high sound levels, e.g. because the typical perception of lower frequencies may be less sensitive than for higher frequencies.

On average the difference in sound pressure level between the 20 open and closed pressure valve is 10 dB, going as high as 20 dB for frequencies around 100 Hz. It is to be appreciated that this difference may be further increased by increasing the dimensions of the orifice of the pressure valve, i.e. the opening cross-section. Accordingly, in an embodiment a cross-section of a sound passage formed by the pressure relay channel is at 25 least 0.5 mm2 when the pressure valve is in an open position.

The various elements of the embodiments as discussed and shown offer certain advantages, such as providing a feedback for both static and dynamic body postures. Of course, it is to be appreciated that any one of the 30 above embodiments or processes may be combined with one or more other 22 embodiments or processes to provide even further improvements in finding and matching designs and advantages. It is appreciated that this invention offers particular advantages for systems for evaluation of static or dynamic arm movements, and in general can be applied for any type of movement 5 involving the measurements of angles and assignment into static and dynamic periods.

Finally, the above-discussion is intended to be merely illustrative of the present system and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. Thus, while 10 the present system has been described in particular detail with reference to specific exemplary embodiments thereof, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art without departing from the broader and intended spirit and scope of the present system as set forth in the 15 claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

In interpreting the appended claims, it should be understood that the word "comprising" does not exclude the presence of other elements or 20 acts than those listed in a given claim; the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements; any reference signs in the claims do not limit their scope; several "means" may be represented by the same or different item(s) or implemented structure or function; any of the disclosed devices or portions thereof may be combined 25 together or separated into further portions unless specifically stated otherwise; no specific sequence of acts or steps is intended to be required unless specifically indicated; and no specific ordering of elements is intended to be required unless specifically indicated.

Claims

An audio listening apparatus (1) comprising a housing (2) configured to substantially form a pressure seal between an ear canal (11) and an external environment (12); the housing (2) comprising: 5. a pressure transmitting channel (3) extending through the housing (2) between the hearing channel (11) and the external environment (12) adapted to transmit a pressure difference therebetween; - a pressure valve (4) arranged in the pressure transmitting channel (3), the pressure valve (4) adapted to switch between an open or closed position for respectively allowing or preventing an exchange of pressure between the hearing channel (11) and the external environment (12); - an acoustic generator (9) arranged between the pressure valve (4) and the auditory canal (11) adapted to generate an acoustic signal in the auditory canal (11); and 15. a valve control comprising o an actuator (5) adapted to switch the valve between the open and closed position; and o control logic (6) adapted to control the actuator (5); o a pressure sensor (7), adapted to measure an internal pressure level (P1, S1) in the auditory canal (11); wherein the control logic (6) is adapted to control the actuator (5) to switch the pressure valve (4) to an open position when the measured internal pressure level (P1, S1) is above a pressure level threshold value.

The audio listening apparatus according to claim 1, wherein the measured internal pressure level is a function of the internal sound pressure level (S1) in the hearing channel (11) and the pressure sensor comprises an internal microphone adapted to measure the internal sound pressure level ( S1).

Apparatus for listening to audio according to any one of the preceding claims, wherein the pressure sensor further comprises an external microphone adapted to measure an external sound pressure level (S2) of the external environment; and wherein the valve control is arranged to close the pressure valve when the external sound pressure level (S2) is above a specified threshold value for external sound pressure level.

Apparatus for listening to audio according to any of the preceding claims, further comprising - a second pressure valve (14) arranged between the acoustic generator and the hearing channel; - a second actuator (15) adapted to switch the second valve (14) between an open and a closed position for respectively allowing or preventing an exchange of pressure between the auditory canal (11) and the external environment (12); - wherein the control logic (6) is adapted to control the second actuator (15) to switch the second pressure valve (14) to a closed position when a measured external sound pressure level (S2) is above a specified threshold value for external sound pressure level.

The audio listening apparatus according to any one of the preceding claims, wherein the pressure sensor (7) comprises a differential pressure sensor (7ab) adapted to measure a pressure difference (| AP |) between the internal pressure level (PI) and an external pressure level (P2) of the external environment (12); and wherein the pressure level threshold value is a function of the measured external pressure level (P2) such that the control logic (6) is adapted to control the actuator (5) to open the pressure valve (4) when the pressure difference (| ΔΡ |) is higher than a threshold value for pressure difference.

The audio listening apparatus according to claim 5, wherein the control logic (6) is arranged to control the pressure valve (4) such that the pressure difference (| ΔΡ |) between the internal and external pressure levels is equilibrated with a controlled speed of less than 50 Pa / s, preferably 25 Pa / s.

7. Audio listening apparatus as claimed in any of the foregoing claims, wherein the pressure valve is adapted to switch to intermediate cross-sectional openings between the open and closed positions thereby providing a variable cross-sectional opening in the pressure-transmitting channel.

8. Audio listening apparatus according to any one of the preceding claims, wherein the control logic is arranged to control the pressure valve under the influence of control parameters for switching between - reducing a maximum sound pressure level in the auditory canal when listening to sound generated by the acoustic generator by opening the pressure valve to the external environment; - reducing undesirable pressure differences between the auditory canal and the external environment in a controlled manner by providing a variable opening of the pressure valve; - improving a sound experience of a user by closing the pressure valve; or - protecting the ear against external noise by closing the pressure valve.

9. Audio listening apparatus as claimed in any of the foregoing claims, wherein the acoustic generator comprises an electro-acoustic transducer which is electrically connected to a frequency and / or amplitude modulated electrical source which is included in a playback device and the valve control further adapted to open the pressure valve in the pressure transmitting channel as a function of an electrical signal received from the electrical source.

10. Audio listening apparatus according to any of the preceding claims, further comprising a control bypass mechanism adapted to bypass the control logic and control the pressure valve independently of the pressure sensor.

The audio listening apparatus according to any of the preceding claims, wherein the acoustic generator comprises a balanced armature receiver.

The audio listening device according to any of the preceding claims, wherein the pressure transmitting channel is cylindrical and sealed at one end by the pressure valve.

13. Method of controlling an audio listening device (1) comprising a housing (2) configured to substantially form a pressure seal between an ear canal (11) and an external environment (12); the housing (2) comprising: - a pressure transmitting channel (3) extending through the housing (2) between the hearing channel (11) and the external environment (12); - a pressure valve (4) arranged in the pressure transmitting channel (3); and 25. an acoustic generator (9) arranged between the pressure valve (4) and the auditory canal (11); - the method comprising - generating an acoustic signal in the hearing channel (11) using the acoustic generator; - measuring an internal pressure level (P1, S1) in the auditory canal (11); and - switching the pressure valve between an open or closed position to respectively allow or prevent an exchange of pressure between the auditory canal (11) and the external environment (12) through the pressure transmitting channel (3); - wherein the pressure valve (4) is switched to an open position when the measured internal pressure level (PI, SI) is above a pressure level threshold value.

The method of claim 13, wherein the internal pressure level is a function of an internal sound pressure level (S1) of the generated acoustic signal.

15. Method according to claim 13, wherein the internal pressure level (P1) is measured relative to an external pressure level (P2) of the external environment and the pressure valve (4) is switched to an open position when a pressure difference (| ΔΡ |) between the internal and external pressure levels is higher than a threshold value for pressure difference.