US3835263A - Microphone assembly operable in directional and non-directional modes - Google Patents

Microphone assembly operable in directional and non-directional modes Download PDF

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Publication number
US3835263A
US3835263A US00329673A US32967373A US3835263A US 3835263 A US3835263 A US 3835263A US 00329673 A US00329673 A US 00329673A US 32967373 A US32967373 A US 32967373A US 3835263 A US3835263 A US 3835263A
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Prior art keywords
sound
directional
acoustical
microphone assembly
port
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Expired - Lifetime
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US00329673A
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English (en)
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M Killion
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Knowles Electronics LLC
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Industrial Research Products Inc
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Filing date
Publication date
Application filed by Industrial Research Products Inc filed Critical Industrial Research Products Inc
Priority to US00329673A priority Critical patent/US3835263A/en
Priority to GB4352373A priority patent/GB1430200A/en
Priority to AU60484/73A priority patent/AU478572B2/en
Priority to AT820273A priority patent/AT332465B/de
Priority to CA181,886A priority patent/CA991738A/en
Priority to FR7339389A priority patent/FR2216745B1/fr
Priority to NL7317130A priority patent/NL167832C/xx
Priority to JP14367073A priority patent/JPS5317444B2/ja
Priority to DE19742400666 priority patent/DE2400666C3/de
Priority to DK58074A priority patent/DK149294C/da
Priority to CH158974A priority patent/CH587594A5/xx
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Publication of US3835263A publication Critical patent/US3835263A/en
Assigned to KNOWLES ELECTRONICS, INC., 1151 MAPLEWOOD DR., ITASCA, IL., A CORP. OF DE. reassignment KNOWLES ELECTRONICS, INC., 1151 MAPLEWOOD DR., ITASCA, IL., A CORP. OF DE. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: INDUSTRIAL RESEARCH PRODUCTS, INC., A CORP OF DE.
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Assigned to JPMORGAN CHASE BANK AS ADMINISTRATIVE AGENT reassignment JPMORGAN CHASE BANK AS ADMINISTRATIVE AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KNOWLES ELECTRONICS LLC
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    • 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
    • H04R25/40—Arrangements for obtaining a desired directivity characteristic
    • H04R25/402—Arrangements for obtaining a desired directivity characteristic using contructional means
    • 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
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
    • H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means
    • H04R1/38—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means in which sound waves act upon both sides of a diaphragm and incorporating acoustic phase-shifting means, e.g. pressure-gradient microphone

Definitions

  • Curve B shows the frequency response characteristics of a directional device wherein the frequency response rises from a low value as a relatively straight line to a maximum level and then drops off at the higher frequencies.
  • a microphone assembly particularly for use with hearing aids which assembly can be operated either in a directional or a non-directional mode, but which has essentially the same response characteristics relative to the frequency for sound arriving from the preferred direction whether it is operated in a directional or non-directional mode.
  • FIG. 1 is an isometric view, partly cut away, of one embodiment of the inventive microphone assembly in accordance with the invention
  • FIG. 2 is an isometric view of the microphone assembly positioned inversely or upside down relative to FIG. 1 to better show the closure element for the sound inlet;
  • FIG. 3 shows typical characteristic response curves of prior art directional and non-directional devices with the axis of ordinates indicating response in decibels and the axis of abscissas indicating frequency;
  • FIG. 4 shows another embodiment of the microphone assembly according to the invention mounted as in a behind-the-ear type hearing aid.
  • FIG. 5 is another embodiment of a microphone assembly in accordance with the invention.
  • FIG. 6 is another embodiment of a microphone assembly in accordance with the invention.
  • FIG. 7 is still another embodiment of a microphone assembly according to the invention.
  • FIGS. 8 and 9 are characteristic response curves useful in explaining the operation of the structure of FIGS. 5 and 6, with the axis of ordinates indicating response in decibels and the axis of abscissas indicating frequency.
  • the present invention is generally applicable to head mounted hear- 2 ing aids, including the eye-glass mounted type, as indicated in FIGS. 1 and 2, and the behind-the-ear type such as shown in FIGS. 4 and 7.
  • FIG. 1 shows a microphone assembly 11 in accor- 5 dance with the invention mounted in the temple piece 12 of an eye-glass type hearing aid 10.
  • the temple piece 12 includes a recess 13 formed therein in which a microphone capsule 15 is mounted on a suitable isolator pad 18 as is well known.
  • the microphone capsule 15 includes an acoustically responsive diaphragm which is indicated by the dotted line 14, and a transducer assembly, not shown, which couples to the diaphragm. Both the diaphragm and the transducer are well known in the art.
  • the recess 13 is formed in a rela tively inverted position; that is, the top of the recess may be integrally closed; and, sound openings or sound inlets 17 and 19 may be formed in the bottom cover 16. Sound inlets 17 and 19 are formed in spaced relation relative to the longitudinal axis of the temple piece 12 and hence, in a forward and aft direction relative to the wearer.
  • Sound inlets l7 and 19 are positioned to face downwardly for the purpose of permitting draining of the recess 13 to eliminate moisture or condensation from collecting therein, as well as to minimize-dust or dirt from entering the recess.
  • the direction toward which the sound inlets 17 and 19 face can be varied, the only restraint being that the inlets be aligned with the preferred direction of sound reception.
  • FIG. 2 shows an inverted view of FIG. 1 to better show the movable or slidable closure member 28 which selectively closes sound inlet 19, for purposes to be described.
  • closure member 28 is slidably mounted on temple piece 12 and may be of any suitable type provided it is selectively adjustable to close and open the rear sound inlet 19.
  • Other means, such as a plug, for covering or closing sound inlet 19 may be utilized in lieu of closure member 28.
  • the microphone assembly 11 when sound inlet 19 is closed, the microphone assembly 11 operates as a pressure sensitive device having non-directional or omni-directional response. When sound inlet 19 is open, the microphone assembly 11 operates as a directional device having its most sensitive response to sound coming from a forward direction relative to the wearer; and, a minimum response to sound coming from some rearward direction relative to the wearer.
  • microphone capsule 15 includes a first or front sound port 25 and a second or rear sound port 27. Sound ports 25 and 27 convey sound to opposite sides of the diaphragm 14.
  • the microphone capsule 15 could be of the type shown in, for example, US. Pat. No. 3,577,020 to Carlson et al., modified to have two inlet ports, which as mentioned above, communicate with opposite sides of the diaphragm 14.
  • Tube 21 thus conducts or conveys the sound entering the sound inlet 17 directly to sound port 25 of microphone 15.
  • the tube 21 has communication through an acoustical impedance 34 which may comprise an acoustical material mounted over the opening 33.
  • the rear sound inlet 19 opens into an acoustical cavity 22 formed in the recess 13.
  • the cavity 22 that is, as a pressure gradient microphone wherein the.
  • sound inlet 17 Sound coming from a given direction, say the frontal direction, or the left, as oriented in FIGS. 1 and 2 will be effective at sound inlet 17 to be coupled through tube 21 to sound port 25 of microphone capsule and the front side of diaphragm 14.
  • sound port 27 and microphone capsule 15 include an impedance element for providing a suitable phase shift or acoustical time delay to provide a directional response which is maximum in a frontal direction and minimal in a rearward direction.
  • Sound energy also couples from front sound inlet 17 through the parallel path comprising opening 33, passage 26, cavity 22 to rear sound port 27 and diaphragm 14.
  • the relative acoustic impedances of the passageways between sound inlet 17 and acoustical element 34, and between sound inlet 19 and the acoustical element 34 are selected to be low relative to the acoustical impedance of the communication through acoustical element 34. Accordingly, the sound pressure at sound port 25 from sound entering inlet 17 is substantially unaffected by the presence of the element 34.
  • element 34 effectively isolates or blocks sound entering sound inlet 19 from substantially affecting the sound pressure at port 25.
  • the sound pressure at port 27 is substantially unaffected by the presence of element 34.
  • the microphone assembly 11 functions as a non directional or omnidirectional device.
  • the value of the acoustical impedance in element 34 is chosen so that, in cooperation with cavity 22, it produces a phase shift or delay in the sound wave as it arrives at sound port 27 which is equivalent to the delay of the sound emanating from a forward direction in passing between sound inlet 17 and 19 externally of capsule 15.
  • the cavity 22 provides essentially a rigidly closed tube which presents an acoustic reactance provided the dimensions of the cavity are small compared to the wavelength.
  • the differential sound pressure on diaphragm 14' is substantially similar whether the rear sound inlet 19 is open or closed. Note that sound arriving from an undesired direction will be relatively attenuated when inlet 19 is open.
  • the inventive microphone assembly may be operated in either a directional or a non-directional mode without changing its frequency response characteristics for sound emanating from the front or desired direction.
  • a principal feature of the invention is that if the microphone assembly of FIGS. 1 and 2 is operated in a directional mode, the response is substantially the curve, or line B of FIG. 3; and importantly, when the microphone assembly is operated in a non-directional mode, the response also follows the curve B.
  • FIG. 4 shows another embodiment of the inventive microphone capsule 35 mounted in a behind-the-ear type of hearing aid 36 within an acoustically transparent closure 40, which aid includes suitable amplifier means, receiver means, and battery; as labeled and well known in the art.
  • the structure of the microphone assembly of FIG. 4 may be that as illustrated in FIGS. 5 or 6.
  • the microphone capsule 35 is also operable in a directional and non-directional mode and has similar frequency response characteristics whether operating in one or the other mode.
  • Microphone capsule 35 comprises an assembly which in and of itself includes means for adjusting the directional and non-directional characteristics.
  • the microphone capsule 35 can be mounted, for example, in an open recess of a hearing aid device as in FIG. 4, or it could be placed conveniently in a recess of an associated hearing aid housing such as in FIGS. 1 and 2, with the top cover 37 forming a part of the hearing aid housing.
  • the top cover 37 of the microphone capsule 35 has a short tube thereon which forms a front sound inlet 41 and a second short tube positioned in spaced relation to the first tube to form a rear sound inlet 43 therein.
  • the tubes at sound inlets 41 and 43 may be used as coupling tubes.
  • the orientation of the microphone capsule 35 can be such that the sound inlets 41 and 43 open downwardly or sidewardly, provided that a relatively fore and aft spacing exists between the sound inlets 41 and 43 in order to obtain a response pattern with maximum directivity or sensitivity being in the desirable direction relative to the user or wearer.
  • microphone capsule 35 will be considered to be mounted for operation in the orientation shown.
  • the microphone capsule 35 includes a suitable diaphragm 45 mounted to separate the microphone into a first sound cavity 47 and a second sound cavity 49.
  • the first sound cavity 47 is contiguous with the front side or surface of the diaphragm 45 and cooperates with the front sound inlet 41.
  • the second sound cavity 49 is contiguous with the back side of the diaphragm 45 and cooperates with the back or rear sound inlet 43.
  • a removable plug 39 when inserted into inlet 43 prevents access of sound through sound inlet 43.
  • a bulkhead 51 is mounted to provide an acoustical seal between the upper and lower portions of the microphone assembly 35, except for an opening on its lower left side 53 which permits direct communication of sound inlet 41 to sound cavity 47.
  • An acoustical sealing flange or bulkhead 57 separates the space between the bulkhead and top 37 of microphone capsule 35 into essentially first or front chamber 54 and a second or rear chamber 56.
  • a sound opening 59 is formed on flange 57 and a suitable acoustical impedance such as a cloth, screen material, a slit or porous material is positioned across or over opening 59.
  • the diaphragm 45 is attached to any suitable transducer assembly, not shown, to energize the associated electronic circuitry as is well known in the art.
  • the microphone capsule 35 functions as a directional microphone with maximum sensitivity or response to sound coming from a forward direction along a longitudinal line between sound inlets 41 and 43.
  • sound coming from the forward direction will enter the front sound inlet 41, and pass through to cavity 47 to be effective on the front side of the diaphragm 45.
  • the same bit of sound will enter the rear sound inlet 43 into cavity 56 and pass through sound port 55 into cavity 49 to be effective on the rear side of the diaphragm 45.
  • Sound port 55 includes suitable acoustical impedance means to provide a phase shift or delay to sound passing therethrough thus providing a directional characteristic response.
  • the relative acoustic impedances of the passageway between sound inlet 41 and acoustical element 59, and between sound inlet 43 and the acoustical element 59 are selected to be low relative to the acoustical impedance of the communication through acoustical element 59. Accordingly, the sound pressure in cavity 47 and on front of diaphragm 45 from sound entering sound inlet 41 is substantially unaffected by the presence of element 34. The converse is true for the effect of sound entering sound inlet 43. That is, element 59 effectively isolates or blocks sound entering sound inlet 43 from substantially affecting the sound pressure in cavity 47.
  • the closure member 39 is moved to close the rear sound inlet 43.
  • sound is coupled to the diaphragm 45 only through sound inlet 41.
  • Sound entering sound inlet 41 passes to front sound cavity 47 to be effective on the front side of the diaphragm 45.
  • Sound entering front sound inlet 41 also passes through the acoustical impedance of sound opening 59 to rear chamber 56, through acoustical element 55, and rear cavity 49 to be effective on the back side of the diaphragm 45.
  • the opening 59 provides a relatively high acoustical impedance; hence, the phase shift provided by the acoustical impedance of opening 59 and chamber 56 can be selected to correspond to, or match, the phase shift of the sound moving externally of microphone capsule 35 between sound inlet 41 and sound inlet 43.
  • the impedance of opening 59 and the associated screen material is too high an impedance to significantly affect the sound pressure in chamber 56 while the sound inlet 43 is open.
  • the impedance provided by opening 59 and the associated screen material in combination with the impedance of chamber 56 provides the additional phase shift that the sound wave experiences in traveling from sound inlet 41 to sound inlet 43 in the free space externally of the microphone capsule.
  • the performance of the microphone capsule 35 I is substantially the same as the microphones of FIGS. 1 and 2; that is, for sound arriving from the front there is minimal difference in the operating characteristics whether the microphone is operating in the directional or in the non-directional mode. If however, the chamber 56 is relatively small as compared to cavity 49, the transition fron one to the other mode will have an effect on the upper end of the frequency response characteristic. More specifically, in the latter case, the response of microphone capsule 35 is as shown in FIG. 8. That is, when microphone capsule 35 is operated in a directional mode, its performance is indicated by line D; and, its performance when it is operating in a nondirectional mode is given by the line N, which drops off at a lower frequency then line D.
  • the microphone capsule 35 when the microphone capsule 35 is functioning in a non-directional mode with sound inlet 43 closed, the acoustical transmission in the path which may be traced from sound inlet 41, opening 59 and its acoustical resistance, chamber 56 and inlet port 55 to the back side of the diaphragm 45 substantially matches the frontally arriving sound entering through rear sound inlet 43, chamber 56 and rear sound port 55 when sound inlet 43 is open.
  • FIG. 6 Another embodiment of the invention is shown in FIG. 6 wherein the microphone capsule is similar to the microphone capsule of FIG. 5.
  • a principal modification of the structure of FIG. 6 with respect to that of FIG. 5 is that the closure means provided for closing the rear sound inlet 43A is different, and also the flange 57 and the included opening providing an acoustical impedance are eliminated.
  • a further minor difference is that the sound inlets 41A and 43A do not include the associated short tubes.
  • a pivotable vane 67 is mounted to be movable from a vertical position as indicated by the solid lines to a horizontal position as indicated by the dotted lines.
  • Vane 67 can be adjustably positioned such as by suitable knob 69 to a vertical position to leave sound inlet 43A open, and to close or block sound from passing from front sound inlet 41A and chamber to sound port 55A. In this mode of operation, both sound inlets 41A and 43A are open and microphone 65 functions as a directional device as described above.
  • the vane 67 can be moved or positioned in its horizontal position or orientation to block sound from passing through rear sound inlet 43A.
  • the microphone 65 functions as a non-directional device.
  • the characteristic curve D is obtained with the microphone capsule 65 operating in a directional mode and characteristic curve N is obtained with the microphone capsule 65 operating in the non-directional mode.
  • Curves D and N are similar in shape but represent different sensitivities. If the directional characteristic is a cardioid pattern this displacement operating in a nondirectional mode is approximately 6dB.
  • FIGv 7 Still another embodiment of the invention is shown in FIGv 7 wherein a microphone capsule 75 is shown mounted in a suitable recess 77 in a behind-the-ear type hearing aid 70.
  • the microphone capsule 75 inciudes a suitable diaphragm 86 similar to diaphragm 14 of FIG. 1.
  • Capsule 75 is mounted on a suitable isolator pad 76.
  • Recess 77 includesa cover or top 88 having a front sound inlet 79 and a rear sound inlet 81 formed thereon.
  • a suitable closure member 84 is slidably movable toselectively open and close the rear sound inlet 81.
  • the microphone 75 has a front sound port 83 communicating with one side of diaphragm 86 and a rear sound port 85 communicating with the other side of diaphragm 86, the latter port having a suitable acoustical impedance therein.
  • An acoustical impedance member 91 is positioned in the space between the housing of the hearing aid and the microphone to thus divide the recess 77 into a frontal acoustical cavity 87 and a back acoustical cavity 89.
  • Acoustical impedance 91 provides the same function as acoustical impedance 34 in FIG. 1. And, the operation of the device of FIG. 7 is basically the same as that described above for FIG. 1.
  • the device of FIG. 7 When the closure member 84 is in the position shown in FIG. 7, the device of FIG. 7 operates in a directional mode, and when the closure member 84 is moved to close rear sound inlet 81, the device of FIG. 7 operates in a non-directional mode.
  • the acoustical impedance 91 is selected, similarly as discussed above, to have minimal effect on the sound pressure in the two cavities 87 and 89 when sound inlet 81 is open; and, to cooperate with cavity 89 to produce additional phase shift when sound inlet 81 is closed.
  • FIG. 7 conveniently permits making cavity 89 larger than that cavity 92 within microphone capsule 75 which latter cavity is located behind the acoustical element of sound port 85.
  • a microphone assembly selectively operable in directional and non-directional modes, comprising, in combination, diaphragm means positioned to have its front and back sides responsive to sound coupled thereto, at least two spaced sound inlets and at least two sound ports, means providing acoustical communication between said sound inlets and said sound ports, sound entering a first sound port being effective on the front side of said diaphragm, and sound entering a second sound port being effective on the back side of the diaphragm whereby said microphone assembly functions in a directional mode, means for selectively interrupting acoustical communication between the second sound inlet and the second sound port whereby said microphone assembly functions in a non-directional mode when communication between the second sound inlet and the second sound port is interrupted, and an acoustical communication path including an impedance means therein for controllably conveying sound from said first sound inlet to the second sound port to thereby obtain substantially the same response characteristics relative to frequency when the microphone assembly is operated in a directional as when it is operated in in a
  • a microphone assembly as in claim 1 further including an acoustical impedance positioned in said second sound port to provide an acoustical phase shift.
  • a hearing aid microphone assembly selectively operable as a directional device and as a non-directional device comprising at least a pair of spaced sound inlets, a microphone having a diaphragm and at least two sound ports communicating to respectively opposite sides of a diaphragm, means for coupling sound from the first sound inlet to the first sound port, an acoustical communication path including an acoustical impedance means therein for controllably coupling sound from the first inlet to the second sound port, means coupling sound from the second sound inlet to the second sound port, and means for selectively closing and opening said second inlet to cause said hearing aid microphone assembly to function as a non-directional and a directional mode respectively, and the acoustical impedance of said acoustical communications path providing an acoustical match whereby said hearing aid microphone assembly develops substantially the same response characteristics relative to frequency whenit is functioning in a directional mode as when it is functioning in a non-directional mode.
  • a hearing aid as in claim 5 wherein said acoustical passage comprises an elongated tube having one end connected to a sound inlet of the housing and the other end connected to a first port of the microphone.
  • a microphone assembly comprising diaphragm means, first and second sound ports acoustically communicating with opposite sides of the diaphragm means, first and second sound inlets respectively communicating with the first and second ports, one of said sound inlets being selectively'openable and closeable to cause said microphone assembly to function as a directional and non-directional device respectively, and auxiliary acoustical communication path means including impedance means for enabling said microphone assembly to have substantially the same characteristic re- 9 sponse relative to frequency whether it is functioning as a directional or non-directional device.
  • a microphone assembly as in claim 1 wherein said microphone assembly is mountable on a head worn hearing aid and said openings are in a fore and aft relatively spaced relation, whereby by the maximum response sensitivity is in a direction toward the front of the wearer.
  • a microphone assembly as in claim 1 comprising a housing, the diaphragm mounted in said housing to provide a front and back cavity, a bulkhead mounted in the housing to provide a distinct and separable sound communication paths between said sound inlets and said sound ports, an acoustical impedance in one of said paths and means including said bulkhead forming a chamber in said communication path and cooperating with said back cavity to effect the characteristic response of said assembly.
  • a microphone assembly as in claim 7 further including a chamber formed between said second sound opening and said second sound port, a cavity formed between said second sound port and said diaphragm means, said chamber being relatively small as compared to said cavity whereby the transistion from one mode to the other mode will have the effect of shifting the response characteristic at the upper end of the frequency range.
  • a microphone assembly as in claim 7 including a first chamber between the front sound opening and the second sound port, vane means in said first chamber and operable to a first position for closing the rear sound opening to cause the microphone to operate in a non-directional mode, the vane means operable to a second position for closing the acoustical communication between the front sound opening and the rear sound port to cause the microphone to operate in a directional mode, a second chamber formed between the rear sound opening and the rear sound port when said vane means is in the second position whereby some loss in frontal sensitivity is realized when operating in a non-directional mode while the frequency response characteristic curves of the assembly for either mode remain substantially the same.
  • a hearing aid as in claim 5 wherein a first acoustical cavity is formed between said first sound opening and said first sound port, a second cavity is formed between said second sound opening and said second sound port, acoustical impedance means mounted between said sound cavities, and said microphone having an internal cavity formed behind the acoustical element of said sound port and assuring that the second cavity is substantially larger than the internal cavity thereby to assure that there is minimal difference in the sensitivity and frequency characteristics irrespective of the operating mode of the hearingaid.

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  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • General Health & Medical Sciences (AREA)
  • Neurosurgery (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
US00329673A 1973-02-05 1973-02-05 Microphone assembly operable in directional and non-directional modes Expired - Lifetime US3835263A (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
US00329673A US3835263A (en) 1973-02-05 1973-02-05 Microphone assembly operable in directional and non-directional modes
GB4352373A GB1430200A (en) 1973-02-05 1973-09-17 Microphone assembly operable in directional and non-directional modes
AU60484/73A AU478572B2 (en) 1973-02-05 1973-09-20 Microphone assembly operable in directional and nondirectional modes
AT820273A AT332465B (de) 1973-02-05 1973-09-24 Mikrophonanordnung fur eine horhilfe
CA181,886A CA991738A (en) 1973-02-05 1973-09-25 Microphone assembly operable in directional and non-directional modes
FR7339389A FR2216745B1 (enExample) 1973-02-05 1973-11-06
NL7317130A NL167832C (nl) 1973-02-05 1973-12-13 Microfooneenheid voor een hoorapparaat.
JP14367073A JPS5317444B2 (enExample) 1973-02-05 1973-12-24
DE19742400666 DE2400666C3 (de) 1973-02-05 1974-01-08 Mikrophonanordnung, insbesondere für Hörhilfen
DK58074A DK149294C (da) 1973-02-05 1974-02-04 Mikrofonenhed til anbringelse i et hoereapparat
CH158974A CH587594A5 (enExample) 1973-02-05 1974-02-05

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00329673A US3835263A (en) 1973-02-05 1973-02-05 Microphone assembly operable in directional and non-directional modes

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US3835263A true US3835263A (en) 1974-09-10

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US00329673A Expired - Lifetime US3835263A (en) 1973-02-05 1973-02-05 Microphone assembly operable in directional and non-directional modes

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US (1) US3835263A (enExample)
JP (1) JPS5317444B2 (enExample)
AT (1) AT332465B (enExample)
CA (1) CA991738A (enExample)
CH (1) CH587594A5 (enExample)
DK (1) DK149294C (enExample)
FR (1) FR2216745B1 (enExample)
GB (1) GB1430200A (enExample)
NL (1) NL167832C (enExample)

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US4763753A (en) * 1984-07-05 1988-08-16 Etymotic Research, Inc. Insert earphones for audiometry
US4773095A (en) * 1985-10-16 1988-09-20 Siemens Aktiengesellschaft Hearing aid with locating microphones
WO1992022176A1 (en) * 1991-05-28 1992-12-10 Motorola, Inc. Noise cancelling microphone and boot mounting arrangement
US5239588A (en) * 1988-12-21 1993-08-24 Davis Murray A Hearing aid
US5341420A (en) * 1990-09-06 1994-08-23 British Telecommunications Public Limited Company Noise-cancelling handset
US5878147A (en) * 1996-12-31 1999-03-02 Etymotic Research, Inc. Directional microphone assembly
WO2000002419A1 (en) * 1998-07-01 2000-01-13 Resound Corporation External microphone protective membrane
US6101258A (en) * 1993-04-13 2000-08-08 Etymotic Research, Inc. Hearing aid having plural microphones and a microphone switching system
WO2000049836A1 (en) 1999-02-18 2000-08-24 Etymotic Research, Inc. Directional microphone assembly
US20020001391A1 (en) * 2000-03-16 2002-01-03 Resistance Technology, Inc. Acoustic switch with electronic switching capability
WO2002030156A1 (en) 2000-10-05 2002-04-11 Etymotic Research, Inc. Directional microphone assembly
US20020106096A1 (en) * 1999-06-16 2002-08-08 Andi Vonlanthen Behind-the-ear hearing aid
US6546111B2 (en) * 2000-05-30 2003-04-08 As Audio Service Gmbh Hearing aid angle piece for behind-the-ear hearing aids
US6597793B1 (en) 1998-08-06 2003-07-22 Resistance Technology, Inc. Directional/omni-directional hearing aid microphone and housing
US6690806B1 (en) * 1999-04-01 2004-02-10 Resistance Technology, Inc. Various directional/omni-directional hearing aid microphone and housing structures
US20040028252A1 (en) * 2002-04-17 2004-02-12 Mcswiggen John P. Acoustical switch for a directional microphone
US20050018866A1 (en) * 2003-06-13 2005-01-27 Schulein Robert B. Acoustically transparent debris barrier for audio transducers
US20050069164A1 (en) * 2003-09-30 2005-03-31 Sivakumar Muthuswamy Microphone system for a communication device
US6876749B1 (en) 1999-07-12 2005-04-05 Etymotic Research, Inc. Microphone for hearing aid and communications applications having switchable polar and frequency response characteristics
US7072482B2 (en) 2002-09-06 2006-07-04 Sonion Nederland B.V. Microphone with improved sound inlet port
US20060274909A1 (en) * 2003-10-03 2006-12-07 Oticon A/S Hearing aid with printed circuit board and microphone suspension
EP1317870A4 (en) * 2000-05-05 2008-11-26 Etymotic Res Inc REPORT MICROPHONE ASSEMBLY
US20090094817A1 (en) * 2007-10-11 2009-04-16 Killion Mead C Directional Microphone Assembly
US20090252360A1 (en) * 2006-06-02 2009-10-08 Varibel B.V. Hearing aid glasses using one omni microphone per temple
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US20090252360A1 (en) * 2006-06-02 2009-10-08 Varibel B.V. Hearing aid glasses using one omni microphone per temple
US8139801B2 (en) * 2006-06-02 2012-03-20 Varibel B.V. Hearing aid glasses using one omni microphone per temple
US10635382B2 (en) * 2007-04-09 2020-04-28 Staton Techiya, Llc Always on headwear recording system
US20140219464A1 (en) * 2007-04-09 2014-08-07 Personics Holdings, Llc Always on headwear recording system
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US20090094817A1 (en) * 2007-10-11 2009-04-16 Killion Mead C Directional Microphone Assembly
US20110129108A1 (en) * 2008-10-10 2011-06-02 Knowles Electronics, Llc Acoustic Valve Mechanisms
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US20110110550A1 (en) * 2009-11-11 2011-05-12 Analog Devices, Inc. Microphone with Variable Low Frequency Cutoff
US8542858B2 (en) * 2009-12-03 2013-09-24 Siemens Medical Instruments Pte. Ltd. Hearing device with a space-saving arrangement of microphones and sound openings
US20110135127A1 (en) * 2009-12-03 2011-06-09 Siemens Medical Instruments Pte. Ltd. Hearing device with a space-saving arrangement of microphones and sound openings
US20130177192A1 (en) * 2011-10-25 2013-07-11 Knowles Electronics, Llc Vented Microphone Module
US9344809B2 (en) 2013-03-14 2016-05-17 Robert Bosch Gmbh Digital acoustic low frequency response control for MEMS microphones
US9859879B2 (en) 2015-09-11 2018-01-02 Knowles Electronics, Llc Method and apparatus to clip incoming signals in opposing directions when in an off state
US10939217B2 (en) 2017-12-29 2021-03-02 Knowles Electronics, Llc Audio device with acoustic valve
US10869141B2 (en) 2018-01-08 2020-12-15 Knowles Electronics, Llc Audio device with valve state management
US10932069B2 (en) 2018-04-12 2021-02-23 Knowles Electronics, Llc Acoustic valve for hearing device
US10917731B2 (en) 2018-12-31 2021-02-09 Knowles Electronics, Llc Acoustic valve for hearing device
US11102576B2 (en) 2018-12-31 2021-08-24 Knowles Electronicis, LLC Audio device with audio signal processing based on acoustic valve state
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Also Published As

Publication number Publication date
JPS5317444B2 (enExample) 1978-06-08
CH587594A5 (enExample) 1977-05-13
NL167832C (nl) 1982-01-18
DK149294C (da) 1986-09-29
CA991738A (en) 1976-06-22
GB1430200A (en) 1976-03-31
AU6048473A (en) 1975-03-20
NL7317130A (enExample) 1974-08-07
FR2216745B1 (enExample) 1978-11-17
FR2216745A1 (enExample) 1974-08-30
ATA820273A (de) 1976-01-15
DE2400666A1 (de) 1974-08-08
JPS49107723A (enExample) 1974-10-14
DK149294B (da) 1986-04-21
AT332465B (de) 1976-09-27
DE2400666B2 (de) 1977-05-18
NL167832B (nl) 1981-08-17

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