Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R25/00—Electric hearing aids
  • H04R25/30—Monitoring or testing of hearing aids, e.g. functioning, settings, battery power
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R25/00—Electric hearing aids
  • H04R25/30—Monitoring or testing of hearing aids, e.g. functioning, settings, battery power
  • H04R25/305—Self-monitoring or self-testing
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R25/00—Electric hearing aids
  • H04R25/50—Customised settings for obtaining desired overall acoustical characteristics
  • H04R25/505—Customised settings for obtaining desired overall acoustical characteristics using digital signal processing

Definitions

• the invention relates to a method for monitoring a hearing device comprising an electro- acoustic output transducer worn at a user's ear or in a user's ear canal.
• the invention also relates to such a hearing device having self-monitoring function.
• the invention relates to a method for adjusting a behind-the-ear hearing device and also to such an adjustable behind-the-ear hearing device.
• Ear- worn hearing devices such as hearing aids (which have an integrated microphone system) or wireless systems (which comprise a remote audio signal source, such as a remote microphone, and an ear-piece receiver) usually comprise an electro-acoustic output transducer (loudspeaker) which is located in or at least close to the ear canal.
• ITE in-the-ear
• CIC completely in-the-canal
• BTE behind-the-ear
• BTE behind-the-ear
• a frequent problem of such ear-worn hearing devices is that the performance of the loudspeaker may be significantly deteriorated due to blocking with ear wax (cerumen) from the ear canal.
• the loudspeaker performance is deteriorated by wax blocking, the user may not immediately notice this. This may be particularly true for systems used by children, since they usually have much more difficulty in noticing and communicating problems regarding the hearing device.
• EP 1 276 349 Bl relates to a hearing aid with a self-test capability, wherein the hearing-aid automatically undergoes a self-test procedure for determining whether the hearing aid comprises a defect.
• the hearing aid is capable to indicate the presence and the type of defect to the user, for example, on the display of a programming device connected to the hearing aid for service purposes.
• the self-test procedure it is checked whether each of the hearing aid microphones produces a signal. From the absence of such signal it is concluded that the input port to the respective microphone has been occluded by ear wax.
• a hearing device should be provided.
• the first object is achieved by a method as defined in claim 1 and a hearing device as claimed in claim 26, respectively.
• the second object is achieved by a method as defined in claim 22 and a hearing device as claimed in claim 27, respectively.
• the invention is generally beneficial in that, by measuring and analyzing the electrical impedance of the output transducer, the status of the output transducer and/or of an acoustical system cooperating with the output transducer, such as a tubing of a BTE hearing device, may be evaluated in a simple and efficient manner. According to one aspect, thereby it is enabled to automatically and immediately recognize when the output transducer or an acoustical system cooperating with the output transducer is blocked by ear wax or when the output transducer is damaged.
• the length and/or diameter of the tubing of a BTE hearing device can be automatically determined in a simple manner, and the thus determined length and/or diameter of the tubing can be used to optimize the operation parameters of the hearing device according the determined length and/or diameter of the tubing in order to optimize the acoustical performance of the hearing device.
• FIG. 1 is a block diagram of a first embodiment of a hearing device according to the invention
• Fig. 2 is a block diagram of a second embodiment of a hearing device according to the invention.
• Fig. 3 is an example of how the electrical impedance of the output transducer of a hearing device according to the invention may be measured
• Fig. 4 shows schematically the set-up for the test measurements of Figs. 5 and 6;
• Fig. 5 is a plot of the voltage measured at the resistor of Fig. 4 as a function of frequency obtained in test measurements with the set-up of Fig. 4 for different obstruction levels of the loudspeaker;
• Fig. 6 is a plot of the acoustic output level curve of the loudspeaker measured with the set-up of Fig. 4 in a 1.4 cc coupler for different loudspeaker obstruction levels.
• Fig. 1 is a block diagram of a first example of a hearing device for which the invention can be used, wherein the hearing device is a hearing aid 10 which comprises a microphone arrangement 12 (which may consist of two spaced-apart microphones for enabling acoustic beam forming capability), a central processing unit 14 for processing the audio signals produced by the microphone arrangement 12, a power amplifier 16 for amplifying the processed audio signals from the central processing unit 14, and a loudspeaker 18 for stimulating the user's hearing with the processed amplified audio signals from the microphone arrangement 12.
• the hearing aid 10 could be of the ITE or CIC type, in which cases the loudspeaker 18 would be located in the ear canal of the user.
• the loudspeaker 18 may cooperate with an acoustical system 20 located downstream of the loudspeaker 18, which may comprise, for example, a wax filter 22, acoustical filters 24 and some kind of tubing 26.
• Such tubing 26 will have a significant length if the hearing aid 10 is of the BTE type, in which case the loudspeaker, together with the hearing aid 10, will be
• Fig. 2 is a block diagram of an alternative embodiment of a hearing device, wherein the hearing device is a wireless ear-piece 110 which represents the receiver unit of a wireless audio system and which receives audio signals from a remote transmission unit 143 via a wireless audio link 145.
• the transmission unit comprises a microphone arrangement 144 (which may consist of two or more spaced-apart microphones for enabling acoustic beam forming capability), an audio signal processing unit 146 for processing the audio signals from the microphone arrangement 144, a transmitter 148 and an antenna 150.
• the audio link 145 will be an FM link.
• the receiver unit 1 10 comprises an antenna 152, a receiver 154 for recovering the audio signals from the signal received at the antenna 152, a central processing unit 114 for processing the received audio signals, a power amplifier 116 for amplifying the processed audio signals, and a loudspeaker 118.
• the loudspeaker 118 may cooperate with an acoustical system located downstream of the loudspeaker 118, for example, a wax filter 22.
• the loudspeaker 118 will be located in or at the ear canal.
• the loudspeaker 118 may be integrated into the receiver unit 110, as shown in Fig. 2, or it may be mechanically and electrically connected thereto.
• an analyzer unit 30 is provided which may be activated by the central processing unit 14, 114 and which serves to measure the electrical impedance as a function of frequency of the loudspeaker 18, 118 and to provide the corresponding measurement result to the central processing unit 14, 114 in order to enable the central processing 14, 114 to produce a status signal representative of the status of the loudspeaker 18, 118 and/or the acoustical system 20, 120 cooperating with the loudspeaker 18, 118.
• the measured electrical impedance as a function of frequency of the loudspeaker 18, 118 provided by the analyzer unit 30 is evaluated in the central processing unit 14, 114 in order to generate the respective status signal.
• an acoustic alarm signal may be produced by the central processing unit 14, 114 with the help of the loudspeaker 18, 118 in order to provide the user with an acoustic alarm.
• acoustic alarm may comprise an alarm tone and/or a voice
• the status signal may be transmitted from the central processing unit 14, 114 to a remote device 32 via a wireless link 34 which possibly is an inductive link utilizing an inductive antenna 38 included in the remote device 32 and an inductive antenna 36 connected to the central processing unit 14, 114.
• the remote device 32 further includes a signal processing unit 40 for processing the signals received by the antenna 38 and a display 40 for displaying the alarm signal received via the inductive link 34, which in this embodiment will be an optical alarm signal rather than an acoustic alarm signal.
• the remote device 32 could be used by the user of the hearing device 10, 110, or, in particular in the case of Fig. 2, it could be used by the person using the transmission unit 143, for example, the teacher in a classroom of pupils using the receiver unit 110. hi this case, the remote device 32 could be functionally integrated within the transmission unit 143.
• the inductive link 34 may be bidirectional link. In this case, transmission of the status signal from the hearing device 10, 110 may be initiated by receipt of a polling command at the hearing device 10, 110 transmitted from the remote device 32. Thereby, for example, the teacher in the classroom may check whether the loudspeaker 118 used by each pupil works properly.
• the bidirectional link 34 may serve to monitor also other components of the system, such as battery status, status of the audio link 145, etc.
• measurement of the electrical impedance of the loudspeaker 18, 118 and the subsequent analysis of the measured electrical impedance will be repeated in regular intervals.
• the measured electrical impedance as a function of frequency will be analyzed by comparing the measured electrical impedance to reference data stored in the hearing device 10, 110.
• reference data may be generated in the manufacturing process of the hearing device 10, 110.
• the resonance frequency and/or the quality factor of the loudspeaker 18, 118 are analyzed by measuring the electrical impedance as a function of frequency.
• the status signal will be provided as an alarm signal if the difference between the actually measured electrical impedance data and the stored reference data exceeds a predetermined threshold, wherein the magnitude of the difference between the measured the loudspeaker 18, 118, for example of the degree of the mechanical obstruction of the loudspeaker 18, 118 by ear wax.
• the evaluation of the status of loudspeaker 18, 118 and/or the acoustical system 20, 120 cooperating with the loudspeaker 18, 118 may include an evaluation of whether the loudspeaker 18, 118 is working according to specification.
• such evaluation will include a check of whether the loudspeaker is still working properly or whether it is out of order.
• the system will include a tubing 26 extending from the loudspeaker 18 into the user's ear canal.
• the length and/or the diameter of such tubing 26 can be selected individually by the fitter. If the length/diameter of the tubing 26 is known, the acoustical performance of the BTE hearing aid can be optimized. Due to the acoustical coupling of the tubing 26 to the loudspeaker 18 it is possible to estimate from the measured electrical impedance of the loudspeaker 18 the length/diameter of the tubing 26 used for each BTE hearing aid 10.
• the central processing unit 14 of the hearing aid 10 may provide for a signal representative of the determined length/diameter of the tubing 26, which signal is supplied to the fitting computer.
• FIG. 3 An example of how the measurement of the electrical impedance of the loudspeaker 18, 118 can be done by the analyzer unit 30 as given in Fig. 3.
• the voltage on a serial resistor 60 located between the ground and the loudspeaker 18 is measured by voltmeter 62.
• the voltage curve i.e. the voltage as a function of frequency
• the electric impedance - and hence the voltage measured by the voltmeter 62 - will be different depending on whether the loudspeaker is open or blocked. Even if the loudspeaker 18 is only partly blocked (resulting in a relatively small acoustic attenuation), a change in voltage will be observed.
• Fig. 5 shows the voltage measured at the resistor 60 as a function of frequency for different levels of obstruction, namely for totally closed filter (close acoustic output, labeled “close”), different intermediate levels of obstruction (partly closed acoustic output, labeled "Half 1" to "Half 4", measurement without filter (open acoustic output, labeled "Nofilter”) and measurement with filter (open acoustic output, labeled "Wsfilter”).
• the loudspeaker 18 was fluid damped.
• Fig. 5 different voltage levels are obtained for different obstruction levels of the loudspeaker 18, 118.
• the voltage difference is obviously the largest at the resonance frequency of the loudspeaker 18, 118 (in the present case about 3,200 Hz).
• the quality factor decreases due to the parasitic acoustical resistance.
• the air volume between the loudspeaker 18 and the "stopper" creates a compliance (acoustic capacitor) in parallel with the standard compliance of the loudspeaker diaphragm. If the acoustic resistor is replaced by a compliance, the quality factor increases, but the resonance frequency also increase to about 4,000 Hz.
• Fig. 6 shows the acoustic output level of the loudspeaker 18 measured in a 1.4 cc coupler as a function of frequency for the various obstruction levels of Fig. 5.
• the resonance frequency of the loudspeaker in free space is stored in the hearing device 10, 1 10 during the manufacturing process. Later, when the hearing device 10, 110 is operated, the analyzer unit 30 generates the stored resonance frequency and measures the voltage on the resistor 60 at this frequency. If the measurement shows too much of a difference, an alarm signal is created, as already explained above, for example, telling the user that the loudspeaker is blocked and should be cleaned.

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• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Otolaryngology (AREA)
• Acoustics & Sound (AREA)
• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Neurosurgery (AREA)
• Signal Processing (AREA)
• Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
• Circuit For Audible Band Transducer (AREA)
• Alarm Systems (AREA)
• Selective Calling Equipment (AREA)
• Headphones And Earphones (AREA)
• Stereophonic System (AREA)

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Cited By (13)

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• 2006
  • 2006-06-12 EP EP06762017A patent/EP2039216B1/de active Active
  • 2006-06-12 DK DK06762017.9T patent/DK2039216T3/da active
  • 2006-06-12 DK DK10172487.0T patent/DK2244492T3/da active
  • 2006-06-12 WO PCT/EP2006/005625 patent/WO2007144010A1/en not_active Ceased
  • 2006-06-12 EP EP10172487.0A patent/EP2244492B1/de active Active
  • 2006-06-12 DE DE602006016655T patent/DE602006016655D1/de active Active
  • 2006-06-12 AT AT06762017T patent/ATE480109T1/de not_active IP Right Cessation

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