United States Patent
`Saito
`
`1:9
`
`[11]
`[45]
`
`4,456,795
`Jun, 26, 1984
`
`[54] BEHIND-THE-EAR TYPE HEARING AID
`
`[75]
`
`Inventor:
`
`OsamuSaito, Akishima, Japan
`
`[73] Assignee:
`
`Rion Kabushiki Kaisha, Tokyo,
`Japan
`
`32 and 34, edited by Michael C. Poliack and published
`in 1980 by Grune & Stratton, Inc., New York, N.Y.
`Hallowell Davis and S. Richard Silverman, “Hearing
`and Deafness”, 4th ed., p. 314, published in 1978 by
`Holt, Rinehart and Winston.
`
`[21] Appl. No.: 343,334
`
`[22] Filed:
`
`Jan, 27, 1982
`
`[30] Foreign Application Priority Data
`Feb. 13, 1981 [JP] Japan oo...csssssesssssssseressnesscessssesee56-19016
`
`Tint. C03 oc ccesecesenesensenees HO4R 25/02
`[51]
`E52] U.S. C1. eeeceeceseceeseeeees 179/107 H; 179/107 FD;
`381/68; 381/69 |
`[58] Field of Search............ 179/107 H, 107 S, 107 R,
`.
`179/107 FD; 381/68, 69
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`7/1969 Hassler 0.0...ssesssscssessees 179/107 H
`3,458,668
`1/1970 Rosemond
`179/107 FD
`3,491,214
`.. 179/107 H
`3/1974 Gage.............
`3,748,390
`8/1974 Elly. w.ccccscsccssscsssssssscsssereere 179/107 H
`3,749,853
`
`«. 179/107 FD
`3,875,349 4/1975 Ruegg ...
`3/1976 PLeves ......ccesssssstescesseeseees 179/107 H
`3,946,168
`
`4,142,072 2/1979 Berland 0.0... sscsseees 179/107 FD
`
`OTHER PUBLICATIONS
`
`WayneJ. Staab, “Hearing Aid Handbook”, p. 55, pub-
`lished as Tab Books No. 987, in 1978.
`“Amplification for the Hearing-Impaired”, 2nd ed., pp.
`
`Primary Examiner—Harold I. Pitts
`Assistant Examiner—L,. C. Schroeder
`Attorney, Agent, or Firm—-Wenderoth, Lind & Ponack
`
`ABSTRACT
`[57]
`A behind-the-ear type hearing aid which includes a
`main body adapted to hang on the user’s earlobe on the
`rear side, an opening disposed at the front end of the
`main body to communicate with a microphone used for
`normal conversation, and a pair openings disposed on
`its rear end portion to communicate with a closed talk-
`ing microphone for use with telephone conversations
`disposed in the main body. The close talking micro-
`phone may be connected to a low-pass filter with a
`cutoff frequency of about 1,000 hertz. The close talking
`microphone mayalso include two pressure type micro-
`phones which are substantially identical in sensitivity
`and are disposed adjacent to each other. One of those
`microphones has an output connected to that of the
`other microphone through a phase inverter with or
`without a gain control connected across the phase in-
`verter.
`
`11 Claims, 6 Drawing Figures
`
`
`
`APPLE 1113
`APPLE1113
`
`1
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`

`

`U.S. Patent
`
`Jun. 26, 1984
`
`4,456,795
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`
`_ FILTER
`
`
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`RESPONSE INdB
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`36
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`(wi)
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` NEAR
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`/
`
`FAR
`FIELD
`“
`FIELD
`4
`
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`FREQUENCY IN Hz
`
`FIG. 4
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`38
`
`40
`
`,
`
`LP
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`42
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`30b?
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` puASE
`INVERTER
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` PHASE
`
`
`
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`INVERTER
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`2
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`passages disposed in the main body to reach the close
`talking microphone, the pair of sound passages being
`substantially equal in length and opening on twooffive
`surfaces defining the rear end portion of the main body.
`The pair of sound passages may preferably open on
`the bottom surface and rear or an exposedlateral sur-
`face of the rear end portion of the main body.
`In order to control the frequency response character-
`istic of the close talking microphone, the microphone
`may be connected to a low-passfilter.
`The close talking microphone may advantageously
`include a pair of pressure type microphones substan-
`tially identical
`in both sensitivity and frequency re-
`sponse and disposed adjacent to each other, and further
`include a phase inverter connected between an output
`of one of the pressure type microphonesandthat of the
`other pressure type microphone.
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`BRIEF DESCRIPTION OF THE DRAWING
`
`The present invention will become more readily ap-
`parent from the following detailed description taken in
`conjunction with the accompanying drawing in which:
`FIG. 1 is a perspective view of one embodiment
`according to the behind-the-ear type hearing aid of the
`present invention;
`;
`FIG.2 is a graph illustrating the frequency response
`characteristics of a close talking microphone in which
`the present invention is interested;
`FIG.3 is a schematic sectional view of a close talking
`microphone used with the present invention;
`FIG.4 is an electrical circuit diagram of the close
`talking microphone as shown in FIG. 3 and including
`means for improving the frequency response thereof;
`FIG.5 is an electrical circuit diagram of a modifica-
`tion of the close talking microphone shownin FIG.3;
`and
`FIG.6 is a diagram similar to FIG. 4 but illustrating
`a- modification of the arrangement shownin FIG.4.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`BEHIND-THE-EAR TYPE HEARING AID
`
`BACKGROUNDOF THE INVENTION
`
`This invention relates to improvements in a behind-
`the-ear type hearing aid.
`Conventional behind-the-ear type hearing aids have
`comprised a main body and a hook extending from the
`main body and arranged to engage the upper end of the
`earlobe of the user to hang the main body on the ear
`thereof. Those hearing aids have been divided into the
`‘front and bottom microphonetypes. In the front micro-
`phone type, a microphone has been disposed on an
`upper or a lowerside of the front end of the main body
`and in the bottom microphonetype, a microphone has
`been disposed on a bottom,a lateral side or the rear end
`of the main body. A self-contained amplifier has then
`been disposed within the main body so as to be con-
`nected across the microphone and an associated re-
`ceiver which, in turn, communicates with the external
`auditory meatus of the user through a sound passage-
`way extending through the main body and the hook.
`The microphonehas been generally used with normal
`conversation but may be also uséd to receive voices
`from a receiver of a telephone handset by placing the
`same against the receiver. At that time, the microphone
`of the bottom microphonetype has occupied a position
`which is convenient to receive voices from the tele-
`phonereceiver but it has been objectionable when used
`with normal conversations because wind noise may
`occur about the microphone. On the other hand, the
`microphone of the front microphone type has been
`disadvantageousin that, as the same is disposed on the
`upper portion of the main body, the telephone receiver
`must be located on the upper portion of the ear of the
`user which is inevitably attended with the telephone
`transmitter positioned so as to be spaced from the user’s
`mouth, resulting in the front microphone type being
`hard to be‘used. In addition, the front microphone type
`has encountered the problem that voice from the tele-
`phone receiver partly leaks through an associated ear
`plug inserted into the external auditory meatus of the
`user so as to reach the front surface of the telephone
`receiver with the result that howling is apt to occur.
`Asa result, it has been undesirable to selectively use
`the single microphone on behind-the-ear type hearing
`aids with both normal and telephone conversation.
`There have been already known behind-the-air hear-
`ing aids comprising a microphonefor use with normal
`conversations and a telephone pickup coil for picking
`up a magnetic leakage flux from an associated telephone
`set for purposes of telephone conversation. However,
`telephone sets have been further improvedto decrease
`the magnetic leakage flux therefrom to an extent thatit
`is inevitably difficult to utilize telephone pickup coils
`for telephone conversations.
`,
`Accordingly, it is an object of the present invention
`to provide a new and improved behind-the-ear type
`hearing aid capable of hearing voices from a telephone
`set which are substantially free from a magnetic leakage
`flux therefrom.
`SUMMARYOF THE INVENTION.
`The present invention provides a behind-the-ear type
`hearing and comprising a main body, having a generally
`rectangular cross section and a rear end portion termi-
`nating at a bottom surface, a close talking microphone
`disposed within the main body and, a pair of sound
`
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`50
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`65
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`Referring now to FIG. 1 of the drawing, there is
`illustrated one embodiment according to the behind-
`the-ear type hearing aid of the present invention. The
`illustrated arrangement comprises a main body 10 hav-
`ing a generally rectangular cross section and somewhat
`curved for the reasons as will be apparent later and a
`hook 12 extending from a front end in this case the
`upperend as viewed in FIG.1 of the mainbody 10. The
`main body 10 includes a pressure type microphone (not
`_ Shown). of the conventional structure disposed therein
`for use with normal conversations and a sound passage-
`way(not shown) extending therethrough to reach the
`microphone and opening at 16 on the upper end of the
`main body 10. Furthermore the main body 10 hasdis-
`’ posed therein a self-contained amplifier for the micro-
`phone, a receiver or an earphone connected to the am-
`plifier, etc., although they are not illustrated only for
`purpose of simplifying the illustration. The hook 12 has
`a sound passageway (not shown) extending there-
`through to reach the earphone (not shown) and a free
`end portion connected via a sound conducting tube 16
`to an ear plug 18. The hook 12 also has a shape suitable
`for hanging the main body 10 on the upperportion of
`the earlobe of the user with the inside or the lefthand
`side as viewed in FIG. 1 of the main body 10 substan-
`tially engaged by the outer root of the earlobe.
`
`3
`
`

`

`3
`Thus, the hook 12 serves to hang the hearing aid on
`the earlobe of the user and also serves to introduce
`amplified voice from the earphone (not shown)into the
`external auditory meatus of the user.
`According to the present invention, another micro-
`phone (not shown)is disposed in the main body 10 and
`preferably on the other or rear end portion thereof
`while a pair of sound passages (not shown) are disposed
`in the main body 10 to reach that microphones and to
`open on two ofthe five surfaces defining the rear end
`portion of the main body 10 for use with telephone
`conversations. In the illustrated example, the pair of
`sound passagewaysopen on the bottom surface and the
`exposed lateral surface of the rear end portion of the
`main body as shownat 20 in FIG.1. This is because the
`user can puthis or her telephone hand-setatits position
`where a transmitter thereof is disposed adjacent to his
`or her mouth while a receiver thereof is disposed close
`to the microphone. Thus, telephone conversations can
`be smoothly effected and also howling can be prevented
`from occurring, because the telephone receiver does
`not pick up voice leaking from the ear plug inserted into
`the external auditory meatus of the user.
`Furthermore, in order to avoid the pickup of external
`noise by the microphonefor telephone conversations to
`the utmost, a close talking microphoneis used as that
`microphone. Close talking microphones are designed
`and constructed so that, when the sound source is far
`therefrom or in a far soundfield, the frequency response
`characteristic thereof decreases with a reduction in
`sound frequency as shown by the dotted curve A in
`FIG.2 wherein a response in decibels of a microphone
`is plotted on the ordinate against a sound frequency
`plotted on the hertzs in abscissa. However, when the
`sound sourceis in the vicinity thereof or in a near sound
`field, the response is raised at lower frequencies until
`the response is substantially uniform at a suitable dis-
`tance from the sound source as shownatsolid line B in
`FIG.2.
`In the present invention, the close talking micro-
`phoneis preferably of a pressure type as shown in FIG.
`3, wherein thereis illustrated in a schematic section the
`fundamental structure of the pressure type close talking
`microphone. Theillustrated arrangement comprises a
`hollow short cylindrical housing 30 including a vibra-
`tory membrane 32 longitudinally halving the interior
`thereof into a pair of sound compartments and having
`both ends closed with respective end plates each pro-
`vided on the central portion with a short cylindrical
`protrusion having a sound passageway 34 extending
`therethrough. Those sound passageways34 are substan-
`tially equal in length and run on the longitudinal axis of
`the housing 30 to be remote from each other and serve
`to introduce sound waves into the sound compartments
`on both sides of the membrane 32 therethrough. The
`membrane32 is connected to any suitable vibration-to-
`voltage converter for converting a vibration of the
`membrane 22 to a corresponding voltage althrough the
`converteris not illustrated only for purposes of simpli-
`fying the illustration.
`Assuming that a sound source is located so as to be
`equidistant from the free ends of the two sound passage-
`ways 34, sound waves from the sound source apply
`sound pressures which are equal in both amplitude and
`phase to the free ends of the sound passageways and
`therefore to both sides of the membrane 32. Thus, the
`membrane 32 does not vibrate, resulting in a null output
`from the microphone. It is also assumed that the sound
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`source is located on an extension ofthe longitudinal axis
`of the housing 30 or of the commonlongitudinal axis of
`the sound passageways 34 and at a distance from the
`housing 30 sufficiently long as compared with that be-
`tween the free ends of the sound passageways 34. Under
`the assumed conditions, the free ends of the sound pas-
`sageways 34 and therefore the both sides of the mem-
`brane 32 receive sound pressure substantially equal in
`both amplitude and phase. As a result, the microphone
`16 can scarcely produce an output.
`However, as the sound source decreases in distance
`from the microphone or the housing 30, a difference
`between a distance from the sound sourceto the free
`end of one of the sound passageways 34 and that from
`the sound sourceto that of the other sound passageway
`34 approaches a distance between the free ends of the
`sound passageways 34. This results in a difference be-
`tween sound pressures occurring and gradually increas-
`ing on the membrane 32. Thus, the microphone pro-
`ducesan increasing output. Thatis, it increases in sensi-
`tivity.
`From the foregoing it is seen that the close talking
`microphone has the function of picking up sound pro-
`duced adjacent
`thereto but not sound produced re-
`motely therefrom and exhibits the effect of suppressing
`noise.
`Since the close talking microphone includesa pair of
`sound passagewaysas described above, they must open
`on the surface of the main body 10 of the hearing aid. As
`described above, the sound passageways open on the
`bottom surface of the main body 10 and the exposed
`lateral surface thereof on the rear end portion which has
`been found to be preferable. It is also preferable to open
`those sound passageways on the-bottom surface and the
`rear surface remote from the user’s earlobe of the rear
`end portion of the main body 10. However,it is to be
`understood that the pair of sound passageways do not
`have to open on the surfaces as described above and
`they may open on twodifferent surfaces of the five
`surfaces defining the rear end portion of the main body
`10. That is, the close talking microphone is only re-
`quired to include a pair of sound passageways opening
`on two of the surfaces defining the rear end portion of
`the main body orhearing aid.
`It is known that, when any person hears voice from
`an associated telephoneset by putting his or her earlobe
`in intimate contact with a receiver thereof or by main-
`taining the earlobe closeto the latter, the telephonesets
`exhibits its intrinsic frequency response characteristic.
`On the other hand, when the person hears voice from
`the telephone set through his or her microphone, the
`latter is difficult to intimately contact the telephone
`receiver. This results in the microphone opening on the
`exterior. Therefore,
`the telephone set exhibit such a
`response characteristic that the lower frequency range
`dropsin responseandas the result, the higher frequency
`range is emphasized. Thus,
`the person hears high-
`pitched voice from the telephoneset and feels displea-
`sure in the sense of hearing. Also, the voice may de-
`crease in articulation.
`Although close talking microphones have been pre-
`liminarily designed and constructed so that they have
`the position of sound sources exhibiting the frequency
`response characteristic optimal for the particular appli-
`cations, they havestill the abovementioned objections
`due to their close talking effect.
`The present invention can also eliminates those objec-
`tions by the provision of a low-passfilter connected to
`
`4
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`

`

`5
`the close talking microphone as shown in FIG. 4. In
`FIG.4,the close talking microphone 36 is connected to
`a lowpassfilter 34 having a cutoff frequency of about
`1,000 hertz. Thefilter 38 is then connected to a junction
`40 subsequently connected to the amplifier (not shown)
`as described above. This measure can attenuate the
`intermediate and higher frequency regions to impart the
`confortable hearing aid effect to the user.
`The close talking microphone as shown in FIG. 3
`may be replaced by a pair of usual pressure type micro-
`phones substantially identical
`in sensitivity to’ each
`-other.
`FIG. 5 shows a modification of the close talking
`microphone shown in FIG.4. The illustrated arrange-
`ment comprises a pair of usual pressure type micro-
`phones 30a and 30b substantially identical in both sensi-
`tivity and frequency response and disposed adjacent to
`each other. The pair of microphones 30a and 30d in-
`clude respective sound passageways such as described
`above and one of the microphones,
`in this case, the
`microphone 30a is directly connected to an amplifier
`(not shown) through a junction 40. The other micro-
`phone 36d is connected to the same amplifier through a
`phase inverter 42 and the junction 40.
`In a far sound field, the microphones 30¢ and 30d
`receive respective sound pressures equal in both ampli-
`tude and phase and produce respective output voltages
`substantially equal to each other because the micro-
`phones 30¢ and 30d are substantially identical in sensi-
`tivity to each other. Therefore, the output voltage from
`the microphone 30a is cancelled out at the junction 40
`by an output from the phase inverter 42. As a result, a
`substantially null voltage is applied to the amplifier (not
`shown).
`In a near soundfield, however, the microphones 30a
`and 30d receive respective sound pressures which are
`different inphase from each other. Therefore, an output
`voltage from the microphone 30a is not cancelled out
`by that from the phase inverter 34. Thus, the amplifier
`(not shown)is applied with the output voltage from the
`microphone 30a added to that from the phase inverter
`42.
`From the foregoing it is seen that the arrangement
`shown in FIG. 5 performs the same function as the
`shownin FIG.4.
`In another modification of the close talking micro-
`phone shownin FIG.6, a gain control 44 is connected
`across the phase inverter 42. In other respects theillus-
`trated arrangementis identical to that shownin FIG.4.
`Therefore, like reference numerals have been employed
`to identify the components identical to those shown in
`FIG.5.
`The gain control 44 controls the gain of the phase
`inverter 42 to adjust the output voltage from the micro-
`phone 305 so that the voltages originating from the
`in-phase sound pressures are not entirely cancelled out
`by each other but a desirable portion thereof can be
`developed at the junction 40. This gain control can
`adjust a position of an associated sound source giving
`the optimum frequency response characteristics.
`In summary, the present invention provides a behind-
`the-ear type hearing aid comprising a main body having
`disposed at the front end thereof an opening of a sound
`passagewayled to a microphone used with normal con-
`versations and disposed on the rear end portion of the
`_Inain openings of two sound passagewaysled to a close
`talking microphone be used for telephone conversa-
`tions. Therefore the hearing aid can be used with tele-
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`phone sets which decreases in magnetic leakage flux
`and is convenient in that when a receiver of an associ-
`ated telephone handset is located adjacent to thelatter
`openingsfor the close talking microphone,a transmitter
`or microphone of the handset can be properly posi-
`tioned adjacent to the mouth ofthe user. Because of the
`use of the close talking microphone, the user can hear
`voice from the receiver of the handset with a high sig-
`nal-to-noise ratio or with the articulation much im-
`proved. Furthermore, for conventional hearing aids
`including the telephone pickup coil,
`the user might
`forget that a three position switch involved changes
`from its position where the coil is put in operationtoits
`position where the particular microphone used with
`usual conversations is put in operation. This might re-
`sult in the situation that the user can hear no sound.
`Therefore, the user has frequently encountered objec-
`tions in that the user cannot hear the desired sound, or
`he or she is possessed with the illusion that his or her
`hearing aid itself is out of order. However, the present
`invention does not always require such a switch and can
`eliminate those objections. More specifically, even
`though the microphone for normal conversations and
`that for telephone conversations would be simulta-
`neously put in operation, the particular normal conver-
`sation can be clearly heard by the microphonefor nor-
`mal conversations but not by the microphonefortele-
`phone conversations. On the contrary, sound from an
`associated telephone set can be clearly heard by the
`microphonefor telephone conversations but not by the
`microphone for normal conversations. Therefore, the
`present invention may only need to be provided with a
`single switch for simultaneously turning the two micro-
`phones on and off. However, when the hearing and is
`used in the street where ambient noise is high, the same
`may be designed and constructed so that only the mi-
`crophonefor telephone conversations is operated under
`consideration of the fact that ambient noise may enter
`the microphone for normal conversations to decrease
`an articulation of voice from a receiver of an associated
`telephone handset. To this end,
`the three-position
`switch included in conventional hearing aids may be
`modified so that, when the switch is put in its position
`wherethe microphonehas been previously put in oper-
`ation, the two microphones are put in operation, and
`whenthe switchis put in its position previously used for
`telephone, only the microphone for telephone conver-
`sations is put in operation with the remaining position
`used to turn the two microphonesoff.
`While the present invention has been illustrated and
`_ described in conjunction with a few preferred embodi-
`ments, it is to be understood that numerous changes and
`modifications may be resorted to without departing
`from the spirit and scope of the present invention.
`Whatis claimedis:
`4. A behind-the-ear type hearing aid comprising a
`main body having a generally rectangular cross section
`and a rear end portion in the form of a pentahedron
`terminating at a bottom surface forming one surface of
`said pentahedron, a microphone for use with normal
`conversation disposed within said main body and a
`sound passageway disposed within said main body so as
`to reach said microphone, a close talking microphone
`disposed within said main body, and a pair of sound
`passagewaysdisposed within a rear portion of said main
`body so as to reach said close talking microphone,said
`pair of sound passageways opening on twooffive sur-
`
`5
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`

`7
`faces defining the pentahedral rear end portion of said
`main body.
`2. A behind-the-ear type hearing aid as claimed in
`claim 1, wherein said pair of sound passageways respec-
`tively open on the bottom surface and the exposedlat-
`eral surface of said rear end portion of said main body.
`3. A behind-the-ear type hearing aid as claimed in
`claim i, wherein said pair of sound passageways respec-
`tively open on the bottom surface and the rear surface
`of said rear end portion of the main body.
`4. A behind-the-ear type hearing aid as claimed in
`claim 1, wherein said close talking microphoneis con-
`nected to a low-passfilter having a cutoff frequency of
`about 1,000 hertz.
`5. A behind-the-ear type hearing aid as claimed in
`claim 1, wherein said close talking microphone com-
`prises a pair of pressure type microphones which are
`substantially identical in sensitivity and are disposed
`adjacent to each other, and wherein a phase inverteris
`connected between an output of one of said pair of
`pressure type microphones andthat of the other ofsaid
`pair of pressure type microphones.
`6. A behind-the-ear type hearing aid as claimed in
`claim §, wherein a gain control is connected across said
`phase inverter.
`7. A behind-the-ear type hearing aid comprising a
`main body having a generally rectangular cross section
`and a rear end portion terminating at a bottom surface,
`a close talking microphone disposed within said main
`body, and a pair of sound passagewaysdisposed within
`said main bodyso as to reach said close talking micro-
`phone,said pair of sound passageways being substan-
`tially equal in length and opening on two offive sur-
`faces defining the rear end portion of said main body;
`wherein said pair of sound passageways respectively
`open on the bottom surface and the exposedlateral
`surface of said rear end portion of said main body.
`8. A behind-the-ear type hearing aid comprising a
`main body having a generally rectangular cross section
`and a rear end portion terminating at a bottom surface,
`a close talking microphone disposed within said main
`
`8
`body, and a pair of sound passagewaysdisposed within
`said main bodyso as to reach said close talking micro-
`phone, said pair of sound passageways being substan-
`tially equal in length and opening on twooffive sur-
`faces defining the rear end portion of said main body;
`wherein said pair of sound passageways respectively
`open.on the bottom surface and the rear surface of
`said rear end portion of the main body.
`9. A behind-the-ear type hearing aid comprising a
`main body having a generally rectangular cross section
`and a rear end portion terminating at a bottom surface,
`a close talking microphone disposed within said main
`body, and a pair of sound passageways disposed within
`said main body so as to reach said close talking micro-
`phone, said pair of sound passageways being substan-
`tially equal in length and opening on twooffive sur-
`faces defining the rear end portion of said main body;
`wherein said close talking microphone is connected
`to a low-pass filter having a cutoff frequency of
`about 1,000 hertz.
`10. A behind-the-ear type hearing aid comprising a
`main body having a generally rectangular cross section
`and a rear end portion terminating at a bottom surface,
`a close talking microphone disposed within said main
`body, and a pair of sound passageways disposed within
`said main body soas to reach said close talking micro-
`phone, said pair of sound passageways being substan-
`tially equal in length and opening on twoof. five sur-
`faces defining the rear end portion of said main body;
`wherein said close talking microphone comprises a
`pair of pressure type microphones which are sub-
`stantially identical in sensitivity and are disposed
`adjacent to each other, and wherein a phase in-
`verter is connected between an output of one of
`said pair of pressure type microphones and that of
`the other of said pair of pressure type microphones.
`11. A behind-the-ear type hearing aid as claimed in
`claim 10, wherein a gain control is connected across
`said phase inverter. *
`&
`x
`*
`id
`
`4,456,795
`
`10
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`6
`
`