US007916888B2
`
`US 7,916,888 B2
`(10) Patent No.:
`a2) United States Patent
`Sapiejewskietal.
`(45) Date of Patent:
`Mar.29, 2011
`
`
`(54)
`(75)
`
`IN-EAR HEADPHONES
`Inventors: Roman Sapiejewski, Boston, MA (US);
`William W. Tice, Amherst, NH (US);
`Jason M. Harlow, Watertown, MA
`(US); Ian M. Collier, Allston, MA (US);
`Kevin P. Annunziato, Medway, MA
`(US); Pericles Nicholas Bakalos,
`Maynard, MA (US); Michael J.
`Monahan,Franklin, MA (US)
`
`(73) Assignee: Bose Corporation, Framingham, MA
`(US)
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`USS.C. 154(b) by 1214 days.
`
`(*) Notice:
`
`(21) Appl. No.: 11/428,057
`
`(22)
`
`Filed:
`
`Jun. 30, 2006
`
`5,761,298 A
`5,781,638 A
`oevoe ‘
`RE37.398 E *
`6,320,960 B1
`D478,991 S
`RE38,351 E
`6,688,421 B2
`
`6/1998 Davisetal.
`7/1998 Hosaka etal.
`soe opensefal.
`10/2001 Nageno veces: 381/371
`11/2001 Lathrop, II et al.
`8/2003 Dyeretal.
`12/2003 Iseberg etal.
`2/2004 Dyer etal.
`(Continued)
`FOREIGN PATENT DOCUMENTS
`
`EP
`
`2/1998
`0825796 A2
`(Continued)
`OTHER PUBLICATIONS
`
`Office Action dated Dec. 21, 2009 for EP 07111157.9-1224.
`
`(Continued)
`
`Primary Examiner — Suhan Ni
`
`Prior Publication Data
`US 2008/0002835 Al
`Jan. 3, 2008
`
`(65)
`
`(51)
`
`ABSTRACT
`(57)
`An earphone includesa first acoustic chamber including a
`reactive elementanda resistive element in parallel, a second
`acoustic chamber separated from the first acoustic chamber
`Int. Cl.
`by an acoustic transducer, and a housing to support the appa-
`(2006.01)
`HOAR 25/00
` ratus from the concha of a wearer’s ear and to extend the
`(52) US.Ch wu... 381/382; 381/370; 381/371; 381/374
`Second acoustic chamber into the ear canal of the wearer’s
`(58) Field of Classification Search.......... 381/370-374,
`381/380-382, 182, 162 ca
`:
`:
`See applicationfile for complete search history.
`A cushion includesa first material and a second material and
`is formed into a first region and a second region. Thefirst
`region defines an exterior surface shapedto fit the concha of
`a human ear. The second region defines an exterior surface
`shapedto fit the ear canal ofa human ear. The first and second
`regions together define an interior surface shaped to accom-
`modate an earphone. Thefirst material occupies a volume
`adjacentto the interior surface. The second material occupies
`a volume betweenthe first material and thefirst and second
`outer surfaces. Thefirst and second materials are ofdifferent
`hardnesses.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`1.893.474 A
`1/1933 Lieber
`4,058,688 A *®
`11/1977. Nishimura etal.
`4,677,679 A
`6/1987 Killion
`4,870,688 A
`9/1989 Vorobaetal.
`aeepone ‘
`tH/loso Aiiberg etal
`4,917,504 A
`4/1990. Scott et al.
`5,327,507 A *
`7/1994 Suzuki oe 381/370
`5,712,453 A
`1/1998 Bungardtetal.
`
`........... 381/372
`
`25 Claims, 12 Drawing Sheets
`
`
`
`1
`
`APPLE 1030
`Apple v. Koss
`IPR2021-00381
`
`APPLE 1030
`Apple v. Koss
`IPR2021-00381
`
`1
`
`

`

`US 7,916,888 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`Sony
`
`5/2004 Wurtz
`12/2004 Sapiejewski
`7/2005 Nassimi
`11/2001 Leedom
`8/2003 Dobrasetal.
`3/2004 Brown
`7/2005 Oliveira et al.
`
`http://www.sonystyle.com/is-bin/INTERSHOP.enfinity/eCS/Store/
`en/-/USD/SY__DisplayProductinformation-
`Start?CategoryName=pa_Headphones_FontopiaEarbud.
`&ProductSKU=MDRED21LP&TabName=specs&var2=,
`MDR ED21LP.
`http://emedia.leeward.hawaii.edu/Frary/sony_mdr-nc 10_review.
`htm, Sony MDR-NC 10 Noise Canceling Stereo Headphones.
`http://www.plantronics.com/media/media_resources/literature/
`FOREIGN PATENT DOCUMENTS
`user_guides/discovery640_ug_en_e.
`pdf;jsessionid=XIFCOZVIKEIBOCQBGNUCFFAKAEZWSIVO,
`EP 1058479 A2=12/2000
`
`EP
`1809069 Al
`7/2007
`Plantronics Discovery 640 User Guide, Printed Jun. 2005, pp. 1-18.
`WO
`9931935 Al
`6/1999
`http://www.plantronics.com/media/media_resources/literature/
`WO
`WO0124579 A2
`4/2001
`cordless_mobile/discovery640_en.
`WO
`WO03069951 Al
`8/2003
`pdf;jsessionid=XIFCOZVIKEIBOCQBGNUCFFAKAEZWSIVO,
`WO
`2007031340 A2
`3/2007
`Plantronics Discovery 640 Bluetooth Headset.
`WO
`2007089845 A2
`8/2007
`http://www.shure.com/PersonalAudio/Products/Earphones/ESeries/
`OTHER PUBLICATIONS
`us_pa__E500_pthcontent, ESOOPTH SoundIsolating Earphones,
`Triple Hi-Definition Drivers.
`International Report on Patentability dated Jul. 9, 2009 for PCT/
`US2007/088805.
`
`6,735,316 Bl
`6,831,984 B2
`6,922,476 B2
`200 1/0043707 Al
`2003/0152244 Al
`2004/0042625 Al
`2005/0147269 Al
`
`EP Search Report dated Dec. 10, 2008 for EP Appl. No. 07111157.
`9-1224 / 1874080.
`International Search Report and Written Opinion dated Jun. 18, 2008
`from International Application No. PCT/US2007/088805.
`
`* cited by examiner
`
`2
`
`

`

`U.S. Patent
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`Mar.29, 2011
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`Sheet 1 of 12
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`US 7,916,888 B2
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`

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`U.S. Patent
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`Sheet 2 of 12
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`Mar.29, 2011
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`US 7,916,888 B2 FIGURE 2A
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`4
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`U.S. Patent
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`Mar.29, 2011
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`Sheet 3 of 12
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`US 7,916,888 B2
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`FIGURE 3A
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`5
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`Sheet 4 of 12
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`U.S. Patent FIGURE 3B
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`6
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`U.S. Patent
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`Mar.29, 2011
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`Sheet 5 of 12
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`US 7,916,888 B2
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`U.S. Patent
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`Mar.29, 2011
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`US 7,916,888 B2
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`U.S. Patent
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`Mar.29, 2011
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`Sheet 7 of 12
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`US 7,916,888 B2
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`U.S. Patent
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`Mar.29, 2011
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`Sheet 9 of 12
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`US 7,916,888 B2
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`U.S. Patent
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`Mar. 29, 2011
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`Sheet 10 of 12
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`US 7,916,888 B2
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`FIGURE 7A
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`FIGURE 7B
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`12
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`

`

`U.S. Patent
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`Mar.29, 2011
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`Sheet 11 of 12
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`US 7,916,888 B2
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`FIGURE 7C
`
`FIGURE 7D
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`13
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`

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`U.S. Patent
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`Mar.29, 2011
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`Sheet 12 of 12
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`US 7,916,888 B2
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`

`US 7,916,888 B2
`
`1
`IN-EAR HEADPHONES
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`Not Applicable
`
`STATEMENT REGARDING FEDERALLY
`SPONSORED RESEARCH OR DEVELOPMENT
`
`Not Applicable
`
`BACKGROUND
`
`This description relates to earphones.
`As shown in FIG. 1, a human ear 10 includes an ear canal
`12 which leads to the sensory organs (not shown). The pinna
`11, the part ofthe ear outside the head, includes the concha 14,
`the hollow next to the ear canal 12, defined in part by the
`tragus 16 and anti-tragus 18. An earphone is generally
`designed to be worn over the pinna,in the concha, or in the ear
`canal.
`
`SUMMARY
`
`In general, in one aspect an earphoneincludesa first acous-
`tic chamberincluding a reactive element anda resistive ele-
`ment in parallel, a second acoustic chamber separated from
`the first acoustic chamber by an acoustic transducer, and a
`housing to support the apparatus from the concha of a wear-
`er’s ear and to extend the second acoustic chamber into the ear
`canal of the wearer’s ear.
`Implementations may include oneor more ofthe following
`features.
`An acoustic damperis in the second acoustic chamber. The
`acoustic damper covers an opening in the second acoustic
`chamber. a portion of the acoustic damper defines a hole. A
`wall of the second acoustic chamber defines a hole that
`
`couples the second acoustic chamberto free space.
`Acushion surroundsa portion of the housing to couple the
`housing to the concha and ear canal of the users ear. The
`cushion includes an outer region formed ofa first material
`having a first hardness, and an inner region formed of a
`second material having a second hardness. Thefirst material
`has a hardness of around 3 shore A to 12 shore A. Thefirst
`material has a hardness of around 8 shore A. The second
`material has a hardness of around 30 shore A to 90 shore A.
`The second material has a hardness of around 40 shore A. A
`first region of the cushion is shaped to couple the second
`acoustic chamber to the ear canal, and a secondregion ofthe
`cushion is shapedto retain the apparatusto theear, the second
`region not extendinginto the ear canal. The cushion 1s remov-
`able. A set of cushions of different sizes is included.
`The reactive element and the resistive element cause the
`first acoustic chamberto have a resonance of between around
`30 Hz and around 100 Hz. Theresistive element includes a
`
`resistive port. The reactive element includes a reactive port.
`The reactive port includes a tube coupling the first acoustic
`chamber to free space. The reactive port has a diameter of
`between around 1.0 to around 1.5 mm anda length ofbetween
`around 10 to around 20 mm. Thereactive port has a diameter
`of around 1.2 mm. The reactive port and the resistive port
`couple to the first acoustic chamberat aboutradially opposite
`positions. The reactive port and the resistive port are posi-
`tioned to reducepressurevariation on a faceofthe transducer
`exposedto the first acoustic chamber. A plurality of reactive
`or resistive ports are about evenly radially distributed around
`
`2
`a center of the acoustic transducer. A plurality of resistive
`ports are about evenly radially distributed around a center of
`the acoustic transducer, and the reactive port couples to the
`first acoustic chamber at about the center of the acoustic
`
`transducer. A plurality of reactive ports are about evenly
`radially distributed arounda center ofthe acoustic transducer,
`and the resistive port couples to the first acoustic chamberat
`about the center of the acoustic transducer.
`
`Thefirst acoustic chamberis defined by a wall conforming
`to a basket ofthe acoustic transducer. Thefirst acoustic cham-
`ber has a volumeless than about 0.4 cm®, including volume
`occupied by the transducer. The first acoustic chamberhas a
`volumeless than about 0.2 cm*, excluding volume occupied
`by the transducer. The second acoustic chamberis defined by
`the transducerand the housing,the housing definesa first and
`a secondhole,the first hole being at an extremity of the wall
`extending into the wearer’s ear canal, and the second hole
`being positioned to couple the acoustic chamberto free space
`whenthe apparatus is positioned in the wearer’s ear; and an
`acoustic damperis positionedacross thefirst hole and defines
`a third hole having a smaller diameter thanthe first hole.
`A circuit is included to adjust a characteristic of signals
`provided to the acoustic transducer. A set of earphones
`includesa pair of earphones.
`In general, in one aspect, a cushion includesa first material
`and a second material and is formedinto a first region and a
`second region. The first region defines an exterior surface
`shaped to fit the concha of a human ear. The second region
`defines an exterior surface shaped to fit the ear canal of a
`humanear. Thefirst and second regions together define an
`interior surface shaped to accommodate an earphone. The
`first material occupies a volume adjacentto the interior sur-
`face. The second material occupies a volume betweenthefirst
`material and the first and second outer surfaces. The first and
`second materials are of different hardnesses.
`Implementations mayinclude one or more ofthe following
`features. The first material has a hardness in the range ofabout
`3 shore A to about 12 shore A. The first material has a hard-
`ness of about 8 shore A. The second material has a hardness in
`
`the range of about 30 shore A to about 90 shore A. Thefirst
`material has a hardness of about 40 shore A.
`
`Other features and advantages will be apparent from the
`description and the claims.
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWINGS
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`FIG. 1 shows a human ear.
`
`50
`
`FIG.2Ais a perspective view of an earphonelocated in the
`ear.
`
`FIG.2Bis an isometric view of an earphone.
`FIG. 3A is a schematic cross section of an earphone.
`FIG.3B is an exploded isometric view of an earphone.
`FIGS. 4A-4C and 6 are graphs.
`FIG. 5 is a circuit diagram.
`FIGS. 7A-7D are isometric views of portions of an ear-
`phone.
`FIGS. 8A and 8Bare side views of a cushion.
`FIG. 8C is a top view of a cushion.
`FIG. 8D is an isometric view of a cushion.
`
`DETAILED DESCRIPTION
`
`As shown in FIGS. 2A and 2B, an earphone 100 hasa first
`region 102 designed to be located in the concha 14 of the
`wearer’s ear 10, and a second region 104to be located in the
`ear canal 12. (FIGS. 2A and 2B show a wearer’s left ear and
`
`55
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`60
`
`65
`
`15
`
`15
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`US 7,916,888 B2
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`3
`corresponding earphone 100. A complementary earphone
`mayfit the right ear, not shown. In some examples, only one
`earphoneis provided. In some examples, a left earphone and
`a right earphone may be provided together as a pair.) A
`cushion 106 couples the acoustic components ofthe earphone
`to the physical structure of a wearer’s ear. A plug 202 con-
`nects the earphoneto a source of audio signals, such as a CD
`player, cell phone, MP3 player, or PDA (not shown), or may
`have multiple plugs (not shown) allowing connection to more
`than one type of device at a time. A circuit housing 204 may
`includecircuitry for modifying the audio signal, for example,
`by controlling its volume or providing equalization. The
`housing 204 may also include switching circuitry, either
`manualor automatic, for connecting the signals output by one
`or another of the above mentioned sources to the earphone. A
`cord 206 conveys audio signals from the source to the ear-
`phones. In some examples, the signals may be communicated
`wirelessly, for example, using the Bluetooth protocol, and the
`cord 206 would notbe included. Alternatively or additionally,
`a wireless link may connect the circuitry with one or more of
`the sources.
`As shown in FIGS. 3A and 3B, the first region 102 of the
`earphone 100 includes a rear chamber 112 and a front cham-
`ber 114 defined by shells 113 and 115, respectively, on either
`side of a driver 116. In some examples, a 16 mm diameter
`driver is used. Other sizes and types of acoustic transducers
`could be used depending, for example, on the desired fre-
`quency response of the earphone. The front chamber 114
`extends (126)to the entrance to the ear canal 12, and in some
`embodiments into the ear canal 12, through the cushion 106
`and ends at acoustic resistance element 118.
`In some
`examples, the resistance element 118 is located within the
`extendedportion 126, rather than at the end,as illustrated. An
`acoustic resistance element dissipates a proportion of acous-
`tic energy that impinges on or passes through it. In some
`examples, the front chamber 114 includes a pressure equal-
`ization (PEQ)hole 120. The PEQ hole 120 serves to relieve
`air pressure that could be built up within the ear canal 12 and
`front chamber 114 whenthe earphone 100 is inserted into the
`ear 10. The rear chamber 112 is sealed aroundthe backside of
`the driver 116 by the shell 113. In some examples, the rear
`chamber 112 includes a reactive element, such as a port (also
`referred to as amass port) 122, anda resistive element, which
`mayalso be formed as a port 124. U.S. Pat. No. 6,831,984
`describes the use of parallel reactive andresistive ports in a
`headphone device, and is incorporated here by reference.
`Although wereferto ports as reactive orresistive, in practice
`any port will have both reactive and resistive effects. The term
`used to describe a given port indicates which effect is domi-
`nant. In the example ofFIG.3B, the reactive port is defined by
`spaces in an innerspacer 117, the shell 113, and an outer cover
`111. A reactive port like the port 122 is, for example, a
`tube-shaped opening in what may otherwise be a sealed
`acoustic chamber, in this case rear chamber 112. A resistive
`port like the port 124is, for example, a small opening in the
`wall of an acoustic chambercovered by a material providing
`an acoustical resistance, for example, a wire or fabric screen,
`that allows someair and acoustic energy to pass through the
`wall of the chamber.
`Eachof the cushion 106, cavities 112 and 114, driver 116,
`damper 118, hole 120, and ports 122 and 124 have acoustic
`properties that may affect the performance of the earphone
`100. These properties may be adjusted to achieve a desired
`frequency response for the earphone. Additional elements,
`such as active or passive equalization circuitry, may also be
`used to adjust the frequency response.
`
`25
`
`30
`
`35
`
`40
`
`45
`
`55
`
`60
`
`4
`The effects of the cavities 112 and 114 andthe ports 122
`and 124 are shownby graph 400 in FIG. 4A. The frequency
`response ofa traditional earbud headphone(that is, one that
`does not extend into the ear canal and does not provide a seal
`to the ear canal) is shown as curve 404 in FIG. 4A.Traditional
`ear bud designs haveless low frequency response than may be
`desired, as shown by section 404a, which shows decreased
`response below around 200 Hz. To increase low frequency
`response andsensitivity, a structure 126, sometimesreferred
`to as a nozzle, may extend the front cavity 112 into the ear
`canal, facilitating the formation ofa seal between the cushion
`106 andthe ear canal. Sealing the front cavity 114 to the ear
`canal decreases the low frequency cutoff, as does enclosing
`the rear of transducer 116 with small cavity 112 including the
`ports 122 and 124. Together with a lower portion 110 of the
`cushion, the nozzle 126 provides better seal to the ear canal
`than earphones that merely rest in the concha, as well as a
`more consistent coupling to the user’s ears, which reduces
`variation in response among users. The tapered shape and
`pliability of the cushion allow it to form a seal in ears of a
`variety of shapes and sizes. The nozzle and cushion design is
`described in more detail below.
`In some examples, the rear chamber 112 has a volumeof
`0.28 cm*, which includes the volume of the driver 116.
`Excluding the driver, the rear chamber 112 has a volume of
`0.08 cm?. An even smaller rear chamber may be formed by
`simply sealing the rear surface ofthe driver 116 (e.g., sealing
`the basket of a typical driver, see the cover 702 in FIG. 7A).
`Other earbud designs often have rear cavities of at least 0.7
`cm’, including 0.2 cm? for the driver.
`The reactive port 122 resonates with the back chamber
`volume. In some examples, it has a diameter in the range of
`about 1.0-1.5 mm anda length in the range ofabout 10-20 mm
`long. In some embodiments, the reactive port is tuned to
`resonate with the cavity volume around the low frequency
`cutoff of the earphone. In some embodiments, this is in the
`low frequency range between 30 Hz and 100 Hz. In some
`examples, the reactive port 122 and the resistive port 124
`provide acoustical reactance and acoustical resistance in par-
`allel, meaning that they each independently couple the rear
`chamber 112 to free space. In contrast, reactance andresis-
`tance can be provided in series in a single pathway, for
`example, by placing a resistive element such as a wire mesh
`screen inside the tube ofa reactive port. In some examples, a
`parallel resistive port is made from a 70x088 Dutch twill wire
`cloth, for example, that available from Cleveland Wire of
`Cleveland, Ohio, and has a diameter of about 3 mm.Parallel
`reactive andresistive elements, embodiedas a parallel reac-
`tive port andresistive port, provides increased low frequency
`response compared to an embodimentusing a series reactive
`and resistive elements. The parallel resistance does not sub-
`stantially attenuate the low frequency output while the series
`resistance does. The frequency response of an earphonehav-
`ing a combination of a small back chamber with parallel
`reactive and resistive ports and a front chamber with a nozzle
`is shown by curve 416 in FIG. 4A. Using a small rear cavity
`with parallel ports allows the earphone to have improved low
`frequency output and a desired balance between low fre-
`quencyandhigh frequency output. Various design options for
`the ports are discussed below.
`High frequency resonancesin the front chamberstructure,
`for example, those represented by peaks 416a, can be damped
`by placing an acoustical resistance (sometimesreferred to as
`a damperor acoustical damper), element 118 in FIGS. 3A and
`3B, in series with the output of the nozzle 126, as shown in
`FIG. 3A. In some examples, a stainless steel wire mesh screen
`of 70x800 Dutch twill wire cloth is used. In some examples,
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`a small hole 128 is formedin the centerof the screen 118. In
`some examples, the screen 118 is about 4 mm in diameter, and
`the hole is about 1 mm. Other sizes may be appropriate for
`other nozzle geometriesor other desired frequency responses.
`The hole 128in the center ofthe screen 118 slightly lowers the
`acoustical resistance ofthe screen 118, but does not block low
`frequency volumevelocity significantly, as can be seen in
`region 422a of curve 422. The curve 416 is repeated from
`FIG. 4A, showing the effects of an undamped nozzle and
`small back chamber with reactive and resistive ports in par-
`allel. Curve 422 has substantially more low frequency output
`than curve 418a, which showsthe effects of a damper 118
`without a hole. A screen with a hole in it provides damping of
`the higher frequency resonances (compare peaks 4225 to
`peaks 416a), though not as much as a screen without a hole
`(compare peaks 4226 to peaks 4185), but substantially
`increases low frequency output, nearly returningit to the level
`found without the damper.
`The PEQ hole 120is located so that it will not be blocked
`whenin use. For example, the PEQ hole 120 is not located in
`the cushion 106 thatis in direct contact with the ear, but away
`from theear in the front chamber 114. The primary purpose of
`the hole is to avoid an over-pressure condition when the
`earphone 100 is inserted into the user’s ear 10. Additionally,
`the hole can used to provide a fixed amount of leakage that
`acts in parallel with other leakage that may be present. This
`helps to standardize response across individuals. In some
`examples, the PEQ hole 120 has a diameter of about 0.50 mm.
`Other sizes may be used, depending on such factors as the
`volumeof the front chamber 114 and the desired frequency
`response of the earphones. The frequency responseeffect of
`the known leakage through the PEQ hole 120 is shown by a
`graph 424 in FIG. 4C. Curve 422 is repeated from FIG. 4B,
`showing the response with the other elements (small rear
`chamberwith parallel reactive and resistiveports, front cham-
`ber with nozzle, and screen damper with small hole in center
`across nozzle opening) but without the PEQ hole 120, while
`curve 428 showsthe response with the PEQ hole providing a
`known amount of leakage. Adding the PEQ hole makes a
`trade offbetween someloss in low frequency output and more
`repeatable overall performance.
`Someor all of the elements described above can be used in
`
`combination to achieve a particular frequency response (non-
`electronically).
`In some examples, additional
`frequency
`response shaping may be used to further tune sound repro-
`duction of the earphones. One way to accomplish this is
`passive electrical equalization using circuitry like that shown
`in FIG. 5. For example, if a resonance remained at 1.55 KHz
`after tuning the acoustic components of the earphones, a
`passive equalization circuit 500 including resistors 502 and
`504 and capacitors 506 and 508 connected as indicated may
`be used. In circuit 500, the output resistance 510 represents
`the nominal 32 ohm electrical impedance of standard ear-
`phones, and the input voltage source 512 represents the audio
`signal input to the headphones, for example, from a CD
`player. Graph 514 in FIG. 6 showsthe electrical frequency
`response curve 516 that results from circuit 500, indicating a
`dip 516a in response at 1.55 KHz correspondingto a Q factor
`of 0.75, with an 8 db decrease in output voltage at the dip
`frequency comparedto the response at low frequencies. The
`actual values ofthe resistors and capacitors, and the resulting
`curve, will depend on thespecific equalization needs based on
`the details of the acoustic components of the earphone. Such
`circuitry can be housed in-line with the earphones, for
`example, inside the circuit housing 204 (FIG. 2A).
`Options for the design of the ports 122 and 124 are shown
`in FIGS. 7A-7D. As shownin FIG. 7A,a reactive port 122a
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`extends out from the back cover 702 of the rear chamber 112.
`A resistive port 124a is located on the opposite side of the
`cover 702. Such a reactive port could be bent or curved to
`provide a more compact package, as shown by a curved port
`1226 formed in the inner spacer 117 in FIG. 7B. In some
`examples, as shown in FIGS. 3B, 7C, and 7D,the full tube of
`the port is formed by the assembly of the inner spacer 117
`with the outer shell 113, which also may form the outer wall
`of the rear chamber 112. In the example of FIGS. 7C and 7D,
`an opening 704in the inner spacer 117 is the beginning ofthe
`port 122. The port curves around the circumference of the
`earphoneto exit at an opening 706 in the outer shell 113. A
`portion of the shell 113 is cut away in FIG. 7D so that the
`beginning opening 704 can be seen. FIG. 7C also shows an
`opening 708 for the resistive port 124. In some examples,
`arranging ports symmetrically around the rear chamber 112
`as shown in FIG. 7A has advantages, for example, it helps to
`balance pressure differences across the rear chamber 112
`(which would appearacross the back of the diaphragm of the
`driver 116, FIG. 7B) that could otherwise occur. Pressure
`gradients across the driver diaphragm could induce rocking
`modes. Some examples may use more than onereactive port
`or resistive port, or both types of ports, evenly radially dis-
`tributed around the rear chamber 112. A single resistive port
`(or single reactive port) could be centrally located, with sev-
`eral reactive(or resistive) ports evenly distributed aroundit.
`The cushion 106 is designed to comfortably couple the
`acoustic elements of the earphoneto the physical structure of
`the wearer’s ear. As shown in FIGS. 8A-8D, the cushion 106
`has an upper portion 802 shaped to make contact with the
`tragus 16 and anti-tragus 18 of the ear (see FIGS. 1 and 2A),
`and a lower portion 110 shaped to enter the ear canal 12, as
`mentioned above. In some examples, the lower portion 110 is
`shapedto fit within but not apply significant pressure on the
`flesh of the ear canal 12. The lower portion 110 is notrelied
`upon to provide retention of the earphone in the ear, which
`allowsit to seal to the ear canal with minimalpressure. A void
`806 in the upperportion 802 receives the acoustic elements of
`the earphone (not shown), with the nozzle 126 (FIG. 3)
`extending into a void 808 in the lower portion 110. In some
`examples, the cushion 106 is removable from the earphone
`100, and cushionsofvarying external size may be provided to
`accommodate wearers with different-sized ears. In some
`
`examples, the cushion 106 is formed of materials having
`different hardnesses, as indicated by regions 810 and 812.
`The outer region 810 is formed ofa soft material, for example,
`one having a durometer of 8 shore A, which provides good
`comfort becauseof its softness. Typical durometer ranges for
`this section are from 3 shore A to 12 shore A. The inner region
`812 is formed from a harder material, for example, one having
`a durometer of 40 shore A. This section provides the stiffness
`neededto hold the cushion in place. Typical durometer ranges
`for this section are from 30 shore A to 90 shore A. In some
`examples, the inner section 812 includes an O-ring type
`retaining collar 809 to retain the cushion on the acoustic
`components. The stiffer inner portion 812 may also extend
`into the outer section to increasethe stiffness of that section.
`
`In some examples, variable hardness could be arranged in a
`single material.
`In some examples, both regions of the cushion are formed
`from silicone. Silicone can befabricated in both soft and more
`
`rigid durometers in a single part. In a double-shot fabrication
`process, the two sections are created together with a strong
`bond between them.Silicone has the advantage of maintain-
`ing its properties over a wide temperature range, and is known
`for being successfully used in applications where it remains
`in contact with human skin.Silicone can also be fabricated in
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`US 7,916,888 B2
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`7
`different colors, for example, for identification of different
`sized cushions,or to allow customization. In some examples,
`other materials may be used, such as thermoplastic elastomer
`(TPE). TPEis similar to silicone, and may be less expensive,
`butis less resistant to heat. A combination ofmaterials may be
`used, with a soft silicone or TPE outer section 812 and a hard
`inner section 810 made from a material such as ABS, poly-
`carbonate, or nylon. In some examples, the entire cushion
`maybefabricated from silicone or TPE having a single hard-
`ness,
`representing a compromise between the softness
`desired for the outer section 812 and the hardness needed for
`the inner section 810.
`
`Other embodiments are within the scope of the following
`claims.
`
`The invention claimedis:
`1. An apparatus comprising:
`a first acoustic chamberincluding a reactive element and a
`resistive elementin parallel,
`asecondacoustic chamberseparated from thefirst acoustic
`chamberby an acoustic transducer, and
`a housing to support the apparatus from the concha of a
`wearer’s ear and extendinto the ear canal ofthe wearer’s
`ear,
`wherein the reactive and resistive elements couple the first
`acoustic chamberto free space when the second acoustic
`chamberis coupled to the wearer’s ear.
`2. The apparatus of claim 1 also comprising an acoustic
`damper in the second acoustic chamber.
`3. The apparatus of claim 2 in which the acoustic damper
`covers an opening in the second acoustic chamber.
`4. The apparatus of claim 2 in which a portion of the
`acoustic damperdefines a hole.
`5. The apparatus of claim 1 in which a wall of the second
`acoustic chamber defines a hole that couples the second
`acoustic chamberto free space.
`6. The apparatus of claim 1 also comprising a cushion
`surroundinga portion of the housing to couple the housing to
`the concha andear canalofthe users ear.
`7. The apparatus of claim 6 in which the cushion comprises
`an outer region formedofa first material havinga first hard-
`ness, and an inner region formed of a second material having
`a second hardness.
`
`8. The apparatus of claim 7 in which the first material has
`a hardness of around 3 shore A to 12 shore A.
`
`9. The apparatus of claim 8 in which the first material has
`a hardness of around 8 shore A.
`
`10. The apparatus of claim 7 in which the second material
`has a hardness of around 30 shore A to 90 shore A.
`11. The apparatus of claim 9 in which the second material
`has a hardness of around 40 shore A.
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`12. The apparatus of claim 6 in whicha first region of the
`cushion is shaped to couple the second acoustic chamberto
`the ear canal, and in which a second region of the cushion is
`shapedto retain the apparatusto theear, the second region not
`extending into the ear canal.
`13. The apparatus of claim 6 in whichthe cushion 1s remov-
`able.
`
`14. The apparatus of claim 13 also comprising a set of
`cushions of differentsizes.
`
`15. The apparatus of claim 1 in whichthe reactive element
`and the resistive element cause the first acoustic chamber to
`have a resonance of between around 30 Hz and around 100
`Hz.
`
`16. The apparatus of claim 1 in whichtheresistive element
`comprisesa resistive port.
`17. The apparatus of claim 1 in whichthe reactive element
`comprises a reactive port.
`18. The apparatus of claim 17 in which thereactive port has
`a diameter of between around 1.0 to around 1.5 mm and a
`
`length of between around 10 to around 20 mm.
`19. The apparatus of claim 17 in whichthereactive port has
`a diameter of around 1.2 mm.
`20. The apparatus of claim 1 in which the reactive port and
`the resistive port are positioned to reduce pressure variation
`ona face of the transducer exposed to the first acoustic cham-
`ber.
`
`21. The apparatus of claim 1 in which the first acoustic
`chamberis defined by a wall conforming to a basket of the
`acoustic transducer.
`22. The apparatus of claim 1 in which the first acoustic
`chamber has a volumeless than about 0.4 cm3, including
`volume occupied byth