Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/08—Mouthpieces; Microphones; Attachments therefor
  • H04R1/083—Special constructions of mouthpieces
  • H04R1/086—Protective screens, e.g. all weather or wind screens
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/08—Mouthpieces; Microphones; Attachments therefor
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
  • H04R25/65—Housing parts, e.g. shells, tips or moulds, or their manufacture
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R2410/00—Microphones
  • H04R2410/07—Mechanical or electrical reduction of wind noise generated by wind passing a microphone

Definitions

• the present invention relates to hearing aids. More specifically the invention relates to a hearing aid with suppression of wind noise. BACKGROUND OF THE INVENTION
• a hearing aid system should be understood as a system for alleviating the hearing loss of a hearing-impaired user.
• a hearing aid system may be monaural and comprise only one hearing aid or be binaural and comprise two hearing aids.
• a hearing aid should be understood as a small, microelectronic device designed to be worn behind or in a human ear of a hearing- impaired user.
• a hearing aid comprises one or more microphones, a microelectronic circuit comprising a signal processor, and an acoustic output transducer.
• the signal processor is preferably a digital signal processor.
• the hearing aid is enclosed in a casing suitable for fitting behind or in a human ear.
• BTE hearing aids are worn behind the ear.
• a housing containing the major electronics parts is worn behind the ear.
• An earplug or earpiece for emitting sound to the hearing aid user is worn in the ear, e.g. in the ear canal.
• a sound tube is used because the output transducer, which in hearing aid terminology is normally referred to as the receiver, is located in the housing of the electronics unit.
• a conducting member comprising electrical conductors is used, because the receiver is placed in the earplug in the ear.
• wind noise is defined as the result of pressure fluctuations at the hearing aid microphones due to turbulent airflow.
• acoustic sounds created by winds are not considered as wind noise here, because such sounds are part of the natural environment.
• Wind noise in hearing devices is a severe problem. Wind noise may reach magnitudes of 100 dB Sound Pressure Level (SPL) and even more. Users of hearing devices therefore often switch their device off in windy conditions, because acoustical perception with the hearing device in windy surroundings may become worse than without the hearing device.
• SPL Sound Pressure Level
• the invention in a first aspect, provides a hearing aid according to claim 1.
• This provides a hearing aid with a wind shield and a hearing aid housing that efficiently suppresses wind noise.
• the invention in a second aspect, provides a hearing aid according to claim 14.
• Fig. 1 illustrates a perspective view of selected parts of a hearing aid according to an embodiment of the invention
• Fig. 2 illustrates, from a first perspective, a wind shield cover according to the
• Fig. 3 illustrates, from a second perspective, the wind shield cover according to the embodiment of Fig. 1 ;
• Fig. 4 illustrates, a perspective view of the hearing aid housing according to the embodiment of Fig. 1 ;
• Fig. 5 illustrates a typical measurement of the power spectrum as a function of
• Fig. 6 illustrates a typical measurement of the power spectrum as a function of
• Fig. 7 illustrates highly schematically a cross-section of a hearing aid according to the embodiment of Fig. 1 ; and Fig. 8 illustrates highly schematically a cross-section of a hearing aid according to another embodiment of the invention.
• the ratio of the wind noise suppression relative to the acoustic attenuation can be improved by providing in the hearing aid a sound transmission channel for sound to be guided from the surroundings and to a microphone inlet, wherein the air flow in the sound transmission channel is made laminar before reaching the microphone inlet.
• the ratio of the wind noise suppression relative to the acoustic attenuation can be improved by selecting appropriately the length of the sound transmission channel. It has been found that the design of the cross-section of the sound transmission channel can further optimize the ratio of the wind noise suppression relative to the acoustic attenuation.
• the first small diameter tube is well suited for suppression of wind noise created by turbulent winds flowing directly into the tube, whereas the second, larger diameter tube is well suited for avoiding picking up wind noise induced by a turbulent wind flow at the opening of the tube.
• the ratio of the wind noise suppression relative to the acoustic attenuation for wind flowing in-plane and parallel with the edges of the plates can be improved by increasing the lateral extent of the plates (and hereby also the propagation distance), because the propagation of the turbulence induced pressure fluctuations is well modeled by a near-field model while the propagation of the main part of the desired sounds from the surroundings is well modeled by a far-field model, and therefore the attenuation of the turbulence induced pressure fluctuations will depend strongly on the propagated distance.
• the acoustic attenuation of sound propagating under a wind shield or generally in a sound transmission channel starts to increase significantly when the plate spacing becomes smaller than 0.15 mm.
• the propagation distance required for transition of a turbulent flow into a laminar flow depends on the value of the plate spacing squared.
• the preferred value of the plate spacing is therefore selected from a range where the acoustic attenuation is limited and where the flow for most normally occurring wind speeds is quickly transformed into a laminar flow.
• the hearing aid 100 consists of a housing part 101, a wind shield cover 102, a connector part 103 and an earpiece (not shown).
• the housing part 101 includes two microphones, a microelectronic circuit comprising a signal processor, an acoustic output transducer, a toggle switch 104 and a push-button 105.
• the connector part 103 is designed for conveying an acoustic signal from the output transducer to the earpiece and towards the eardrum of a user wearing the hearing aid.
• the wind shield cover is adapted for protecting the microphone inlets from dirt and moisture and for suppressing wind noise.
• the hearing aid housing 101 and the wind shield cover 102 are adapted for forming side openings 118a and 118b (similar openings are formed at the opposite side of the hearing aid housing) when the wind shield cover is attached to the hearing aid housing.
• the openings are adapted for allowing sound to be transmitted into the gap between the hearing aid housing and the wind shield cover.
• the front indent 119 is adapted for allowing removal of the wind shield cover from the hearing aid housing using a simple tool.
• Fig. 2 illustrates, from a first perspective, the wind shield cover 102 according to the first embodiment of the invention.
• the wind shield cover has a convex side 106 that is designed to face away from the hearing aid housing (not shown) and a hole 107 adapted for allowing user access to the toggle switch 104 in the hearing aid housing.
• Fig. 3 illustrates, from a second perspective, the wind shield cover 102 according to the first embodiment of the invention.
• the wind shield cover has a concave side 108 that is designed to face towards the hearing aid housing (not shown).
• the concave side 108 has projections 109a, 109b, 110a and 110b adapted for snap locking of the wind shield cover onto the hearing aid housing.
• the concave side further has column like structures 111a and 11 lb and protrusion 122 adapted for assisting in guiding the wind shield into correct position when mounting the wind shield cover onto the hearing aid housing.
• FIG. 4 illustrates schematically the hearing aid housing 101 according to the first embodiment of the invention.
• the housing 101 has two microphone inlets 112 and 113, four indents 109c, 109d and 1 lOd (one is not shown) that are adapted for snap fit connection with the corresponding projections 109a, 109b, 110a and 110b in the wind shield.
• the hearing aid housing has holes 11 Id (one is not shown) adapted for receiving the column like structures 111a and 11 lb in the wind shield cover and a rectangular indent 120 for receiving the wind shield cover protrusion 122.
• a band like projection 114 positioned between the microphone inlets and another projecting structure 115 work together to ensure a uniform and well defined gap distance between the concave side 108 of the wind shield and the surface areas 116a and 116b of the hearing aid housing 101.
• the projecting structure 115 surrounds the toggle switch 104 and incorporates the indents HOd (one is not shown) and holes 11 Id (one is not shown).
• the surface areas 116a and 116b define the surfaces along which sound will propagate from the ambient surroundings and towards the microphone inlets 112 and 113.
• the surface areas 116a and 116b and the projection structures 114 and 115 are surrounded by a rim 117.
• the rim is adapted such that the openings 118a and 118b are formed when the wind shield cover is snap fitted onto the hearing aid housing.
• the indent 120 ensures that the wind shield cover can be easily removed from the hearing aid housing using a tool.
• the gap distance between the wind shield cover 102 and the surface areas 116a and 116b of the hearing aid housing is 0.3 mm.
• the gap distance between the wind shield cover 102 and the surface areas 116a and 116b of the hearing aid housing is in the range between 0.15 and 0.5 mm, preferably in the range between 0.20 mm and 0.35 mm.
• Such a gap distance entails that the air flow beneath the wind shield cover after a short propagated distance is substantially laminar, for most normally occurring wind speeds, and that the acoustic attenuation of the sound as a result of the
• the minimum distance, along the gap i.e. running in the gap between the wind shield cover 102 and the hearing aid housing 101
• the term: "minimum distance, along the gap” shall be interpreted as the shortest distance between an edge of a microphone inlet and a corresponding opening, towards the surroundings, defined by an edge of the wind shield cover and the hearing aid housing.
• the minimum distance, along the gap is at least 1 mm, at least 2 mm, or in the range between 1 mm and 3mm (i.e. larger than 1 mm and smaller than 3 mm). It has surprisingly been found that even such relatively limited gap distances provide a measureable and significant improvement of wind noise reduction.
• the gap distance is 0.3 mm and the minimum distance along the gap is 1.5 mm.
• the width of the openings 118a and 118b both measure 5 mm.
• the width of the openings 118a and 118b measure at least 2 mm, at least 3 mm, or at least 5 mm. It is
• the minimum distance, along the gap, between the openings 118a and 118b and the edges of the corresponding microphone inlets 112 and 113 varies because of the variation of the hearing aid housing width.
• the width of the openings 118a and 118b depends on the variation of the minimum distance such that the ratio of the width of the opening relative to the length of said minimum distance is kept substantially constant.
• Fig. 5 illustrates the results of typical measurements of the power spectrum as a function of frequency for a traditional BTE hearing aid and a BTE hearing aid having a wind shield cover according to an embodiment of the invention.
• the measurements were carried out while the hearing aids were exposed to wind with a speed of 4 m/s.
• Both hearing aids were equipped with two microphones and the power spectrum was obtained using the front microphone in the two hearing aids.
• the figure clearly illustrates that a significant reduction in wind noise can be obtained with a hearing aid having a wind shield cover according to the invention.
• Fig. 6 illustrates the results of typical measurements similar to those described with reference to Fig. 5, except for the fact that the back microphone in the two hearing aids has been used to obtain the power spectrum.
• the figure clearly illustrates that the magnitude of the achievable wind noise reduction depends on the positioning of the microphone.
• the figures 5 and 6 also illustrate that a typical power spectrum for the BTE hearing aid according to the invention is relatively insensitive to the microphone positioning, while this is not the case for the traditional BTE hearing aid.
• FIG. 7 illustrates highly schematically a cross-section of the hearing aid 100 according to the first embodiment of the invention.
• the cross- section is shown in a plane that is perpendicular to a general longitudinal axis of the housing, defined by the line connecting the first and second microphone inlet, and intersecting the first microphone inlet.
• the figure illustrates cross-sections of the hearing aid housing 101, the wind shield cover 102, the first microphone inlet 112 and the first microphone 121.
• the hearing aid is designed such that the hearing aid housing 101 has a cross-section with a circumference in a plane perpendicular to a general longitudinal axis of the housing, defined by the line connecting the first and second microphone inlet, and a wind shield cover 102 that has a cross-section with a length, in said plane, when arranged on the housing, wherein the length of the wind shield cover cross-section is about 30 % of the length of the housing circumference.
• the length of the wind shield cover cross-section is at least 30 % of the length of the housing circumference.
• the length of the wind shield cover cross-section is smaller than 30 % of the length of the housing circumference. This type of wind shield covers are advantageous in the cases where relative short minimum distances along the gap are required in order to obtain a specific microphone frequency response.
• the hearing aid housing consists of an upper and lower part that is fitted together.
• the wind shield cover extends substantially all the way around the hearing aid housing except for a gap opening formed between the ends of the wind shield cover.
• the microphone inlets are positioned in the housing surface opposite the gap opening, hereby achieving, for a given hearing aid housing, the largest achievable minimum distance between the microphone inlet edges and the corresponding gap openings and according to a specific variation the gap opening is positioned in the upper surface of the hearing aid, i.e. the surface opposite the surface of the hearing aid housing that is adapted to rest upon the ear of the intended hearing aid user.
• FIG. 8 illustrates highly schematically a cross-section of a hearing aid 200 according to a second embodiment of the invention.
• the figure illustrates cross-sections of upper and lower hearing aid housing parts 201 and 202, a microphone inlet 212, a microphone 121 and a sound transmission channel 205.
• the sound transmission channel 205 provides for sound to be guided from the surroundings and to the microphone inlet 212.
• the sound transmission channel provides propagation of sound through the interior of the hearing aid housing as opposed to propagation in a gap between a wind shield cover and the outer surface of the hearing aid housing.
• the size of the hearing aid housing can be minimized because the wind shield cover is not required.
• the sound transmission channel can be freely shaped, whereby the achievable minimum distance between the microphone inlets and the opening of the sound transmission channel can be increased.
• the sound transmission channel has a length of 1.5 mm and a cross-section having a first dimension of 0.3 mm and a second dimension of 5 mm,
• the sound transmission channel has a length of at least 1 mm, or a length in the range between 1 and 3 mm, the first dimension of the cross -section is in the range between 0.15 mm and 0.5 mm, preferably between 0.20 and 0.35 mm and the second dimension of the cross-section is at least 2 mm, at least 3 mm or at least 5 mm.
• the hearing aid comprises an insert that forms the sound transmission channel and further is adapted to position and hold the electronic components inside the hearing aid housing.
• the wind shield is provided with small holes just above the microphone inlets. Surprisingly this has been found to make the hearing aid microphones less sensitive to vibrations and hence feedback, while still providing good wind noise suppression. Holes with a diameter in the range between 0.15 mm and 0.30 mm have been found to be appropriate. Other modifications and variations of the structures and procedures will be evident to those skilled in the art.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Neurosurgery (AREA)
• Otolaryngology (AREA)
• Manufacturing & Machinery (AREA)
• Details Of Audible-Bandwidth Transducers (AREA)
• Soundproofing, Sound Blocking, And Sound Damping (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=44735947

Family Applications (1)

Country Status (8)

Families Citing this family (4)

Family Cites Families (9)

• 2011
  • 2011-10-05 KR KR1020137006926A patent/KR20130063530A/ko not_active Application Discontinuation
  • 2011-10-05 EP EP11764215.7A patent/EP2628313B1/de active Active
  • 2011-10-05 DK DK11764215.7T patent/DK2628313T3/en active
  • 2011-10-05 WO PCT/EP2011/067358 patent/WO2012049046A1/en active Application Filing
  • 2011-10-05 CA CA2799086A patent/CA2799086A1/en not_active Abandoned
  • 2011-10-05 JP JP2013515929A patent/JP2013530654A/ja not_active Ceased
  • 2011-10-05 SG SG2012076758A patent/SG184885A1/en unknown
  • 2011-10-05 CN CN2011800270698A patent/CN102918871A/zh active Pending

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events