PATENT DOCUMENT

Publication Number: US-9712905-B2
Application Number: US-201213607551-A
Country: US
Kind Code: B2

Title: Headsets with non-occluding earbuds

Abstract:
Headsets with non-occluding earbuds are disclosed. The earbud includes a non-occluding housing having a directional sound port offset with respect to a center axis of the earbud. The housing can have an asymmetric shape amenable to in-the-ear retention. Additionally, the housing can have a seamless or nearly seamless construction even though two or more parts are joined together to form the housing. Front and back volumes can exist for a driver of the earbud, and embodiments of this invention use mid-mold and rear-mold structures to achieve desired performance from the earbud. For example, the mid-mold structure can be used to tune the front volume while the rear-mold structure can be used to tune the back volume. Apertures may also be included in the housing to further improve the performance of the earbud.

Claims:
What is claimed is: 
     
       1. An earbud comprising:
 a cap; 
 a mid-mold secured to an inner surface of the cap; 
 a driver mounted to the mid-mold, wherein the mid-mold is positioned between the driver and the cap, wherein the mid-mold forms at least a portion of a front volume for the driver, wherein the cap comprises a primary sound port, wherein the mid-mold comprises an aperture aligned with the primary sound port, wherein the driver is operative to direct sound from the driver into the front volume, and wherein the front volume is operative to direct the sound from the front volume through the aperture and through the primary sound port; 
 a rear housing mated with the cap to form an external enclosure about the mid-mold, wherein the rear housing and cap provide a clearance fit with the driver to hold the driver in place; and 
 a rear-mold secured to an inner surface of the rear housing. 
 
     
     
       2. The earbud of  claim 1 , further comprising a mesh assembly coupled to the mid-mold, wherein the mesh assembly covers the primary sound port. 
     
     
       3. The earbud of  claim 1 , wherein the cap further comprises a secondary aperture. 
     
     
       4. The earbud of  claim 3 , wherein the mid-mold comprises a second aperture aligned with the secondary aperture. 
     
     
       5. The earbud of  claim 3 , further comprising a mesh assembly coupled to an inner surface of the cap, wherein the mesh assembly covers the secondary aperture. 
     
     
       6. The earbud of  claim 2 , wherein the mesh assembly is recessed from an external surface of the cap. 
     
     
       7. The earbud of  claim 1 , wherein the mid-mold comprises an alignment feature, the alignment feature operative to align the mid-mold with the cap. 
     
     
       8. The earbud of  claim 1 , wherein the mid-mold comprises at least one recess operative to receive a mesh assembly. 
     
     
       9. The earbud of  claim 2 , wherein the mesh assembly comprises a cosmetic mesh layer and an acoustic mesh layer. 
     
     
       10. The earbud of  claim 1 , wherein the rear housing comprises at least one aperture. 
     
     
       11. The earbud of  claim 10 , further comprising a mesh assembly operative to cover the at least one aperture. 
     
     
       12. The earbud of  claim 1 , further comprising a tail plug, the tail plug operative to acoustically seal a tail portion of the rear housing. 
     
     
       13. The earbud of  claim 1 , further comprising a cable, wherein the rear-mold is overmolded over an end of the cable. 
     
     
       14. The earbud of  claim 1 , wherein the rear-mold comprises a port operative to allow air from behind the driver to escape. 
     
     
       15. The earbud of  claim 13 , wherein the rear-mold further comprises a cutout, wherein the cutout provides access to a bundle of the cable. 
     
     
       16. A tail plug for acoustically sealing a tail portion of an earbud and providing strain relief for a cable of the earbud, the tail plug comprising:
 a hollow skeleton member shaped to fit within the tail portion and constructed from a rigid material, the skeleton member comprising a top portion, a bottom portion, and a side wall extending between the top portion and the bottom portion, the side wall comprising at least one aperture, wherein the at least one aperture is operative to at least partially align with a port in the tail portion when the skeleton member is fit within the tail portion, the skeleton member operative to pass the cable through the top portion and through the bottom portion; and 
 a sealing member constructed from a compliant material, the sealing member coupled to the bottom portion of the skeleton member and operative to form an acoustic seal with the tail portion for forcing air within the tail portion through the port and the at least one aperture. 
 
     
     
       17. The tail plug of  claim 16 , further comprising a mesh that covers the at least one aperture and the port in the tail portion. 
     
     
       18. The tail plug of  claim 16 , wherein the skeleton member is deep drawn from metal. 
     
     
       19. The tail plug of  claim 16 , wherein the skeleton member further comprises at least two additional apertures, and wherein the sealing member is coupled to the skeleton member via an interference fit with the at least two additional apertures. 
     
     
       20. The tail plug of  claim 16 , wherein the skeleton member and sealing member are coupled via a chemical bond. 
     
     
       21. The tail plug of  claim 16 , wherein the sealing member comprises a shaped feature operative to follow a contour of the tail portion and provide an interference fit with the tail portion. 
     
     
       22. The tail plug of  claim 16 , wherein the sealing member is overmolded over the bottom portion of the skeleton member. 
     
     
       23. A terminator operative to serve as the termination point for an earbud cable of an earbud comprising a driver, wherein the earbud cable extends between a first cable end and a second cable, the terminator comprising:
 a structure defining a cavity that forms a rear volume for the driver of the earbud, the structure envelopes and is fixed to only a portion of the earbud cable, wherein the portion of the earbud cable is between the first cable end and the second cable end; and 
 a cutout of the structure providing access to the first cable end of the earbud cable outside of the cavity. 
 
     
     
       24. The terminator of  claim 23 , wherein a perimeter of the structure fits around a rear portion of the driver. 
     
     
       25. The terminator of  claim 23 , wherein the cutout of the structure provides the access to the first cable end of the earbud cable outside of the cavity for coupling the driver to the first cable end of the earbud cable outside of the cavity. 
     
     
       26. The terminator of  claim 23 , wherein the cavity is substantially hemispherical. 
     
     
       27. The terminator of  claim 23 , wherein the portion of the earbud cable comprises tensile members that are tied in a knot. 
     
     
       28. The earbud of  claim 1 , wherein the rear housing comprises a snap that is directly mated to a snap of the cap.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of application Ser. No. 13/528,550, filed Jun. 20, 2012, and also a continuation-in-part of application Ser. No. 13/528,566, filed Jun. 20, 2012, the disclosures of which are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     This disclosure is directed to headsets with non-occluding earbuds and methods for making the same. 
     Headsets are commonly used with many portable electronic devices such as portable media players and mobile phones. Headsets can include one or more cables as well as various non-cable components such as a jack, headphones, and/or a microphone. The one or more cables can interconnect the non-cable components. The headphones, which are the components that generate sound, can exist in different form factors such as over-the-ear headphones, in-the-ear earbuds, or in-the-canal earbuds. In-the-ear earbuds are sometimes referred to as non-occluding earbuds as they generally do not form an airtight seal with a user&#39;s ear. 
     Conventional non-occluding earbuds come with some drawbacks, however. Exposure to normal use can easily cause damage to the earbuds and they may not function properly as a result of the damage. For example, exerting a force on a housing of the earbuds may crack the housing or abruptly pulling on a cable of the earbuds may separate the cable from the earbuds. As another example, exposing the earbuds to external chemicals (e.g., sunscreen) may compromise the structural integrity of the earbuds and cause them to break more easily. In addition to the potential for damage during normal use, the absence of an airtight seal can affect the earbuds&#39; acoustic performance. As a result, the sound quality of non-occluding earbuds may suffer compared to other types of headphones. 
     Accordingly, there is a need for improved non-occluding earbuds that are better able to withstand the rigors of normal use, provide high quality sound, and have an aesthetically pleasing appearance. 
     SUMMARY 
     Headsets with non-occluding earbuds and methods for making the same are disclosed. The earbud includes a non-occluding housing having a directional sound port offset with respect to a center axis of the earbud. The housing can have an asymmetric shape amenable to in-the-ear retention. Additionally, the housing can have a seamless or nearly seamless construction even though two or more parts are joined together to form the housing. Front and back volumes can exist for a driver of the earbud, and embodiments of this invention use mid-mold and rear-mold structures to achieve desired performance from the earbud. For example, the mid-mold structure can be used to tune the front volume while the rear-mold structure can be used to tune the back volume. Apertures may also be included in the housing to further improve the performance of the earbud. 
     According to a particular embodiment, an earbud can include a cap, a rear housing, a mid-mold, a driver, and a rear-mold. The mid-mold may be secured to an inner surface of the cap. The driver may be mounted to the mid-mold. The rear housing may be coupled to the cap such that the rear housing and cap provide a clearance fit with the driver to hold it in place. The rear-mold may be secured to an inner surface of the rear housing. 
     According to another particular embodiment, there is provided a tail plug for acoustically sealing a tail portion of an earbud. The tail plug can include a skeleton member and a sealing member. The skeleton member may be constructed from a rigid material and the sealing member may be constructed from a compliant material. The sealing member may be coupled to a bottom portion of the skeleton member. 
     According to yet another embodiment, there is provided a terminator operative to serve as the termination point for an earbud cable. The terminator can include a molded structure defining a cavity and an opening for accessing an end of the earbud cable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features of the present invention, its nature and various advantages will be more apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings in which: 
         FIG. 1A  shows an exploded view of an illustrative earbud in accordance with an embodiment of the invention; 
         FIG. 1B  shows a perspective front view of the illustrative earbud of  FIG. 1A  in accordance with an embodiment of the invention; 
         FIG. 1C  shows a perspective top view of the illustrative earbud of  FIG. 1A  in accordance with an embodiment of the invention; 
         FIG. 2  shows an exploded view of an illustrative cap sub-assembly in accordance with an embodiment of the invention; 
         FIG. 3A  shows a perspective bottom view of the cap sub-assembly of  FIG. 2  in accordance with an embodiment of the invention; 
         FIG. 3B  shows a perspective side view of the cap sub-assembly of  FIG. 2  in accordance with an embodiment of the invention; 
         FIG. 3C  shows a perspective top view of the cap sub-assembly of  FIG. 2  in accordance with an embodiment of the invention; 
         FIG. 4A  shows a cross-sectional view of the cap sub-assembly of  FIG. 3A , taken from line A-A of  FIG. 3A , in accordance with an embodiment of the invention; 
         FIG. 4B  shows a cross-sectional view of the cap sub-assembly of  FIG. 3A , taken from line B-B of  FIG. 3A , in accordance with an embodiment of the invention; 
         FIG. 4C  shows a partial cross-sectional view of the cap sub-assembly of  FIG. 4B , showing a magnified view of section C from  FIG. 4B  in accordance with an embodiment of the invention; 
         FIG. 5  shows a perspective top view of an illustrative mid-mold structure in accordance with an embodiment of the invention; 
         FIG. 6A  shows a cross-sectional view of the mid-mold structure of  FIG. 5 , taken from line A-A of  FIG. 5 , in accordance with an embodiment of the invention; 
         FIG. 6B  shows a cross-sectional view of the mid-mold structure of  FIG. 5 , taken from line B-B of  FIG. 5 , in accordance with an embodiment of the invention; 
         FIG. 7  shows an exploded view of a mesh assembly in accordance with an embodiment of the invention; 
         FIG. 8  shows an exploded view of an illustrative rear housing sub-assembly in accordance with an embodiment of the invention; 
         FIG. 9A  shows a cross-sectional view of the rear housing sub-assembly of  FIG. 8  in accordance with an embodiment of the invention; 
         FIG. 9B  shows a partial cross-sectional view of the rear housing sub-assembly of  FIG. 9A , showing a magnified view of section B from  FIG. 9A  in accordance with an embodiment of the invention; 
         FIG. 10  shows a cross-sectional view of an illustrative tail plug in accordance with an embodiment of the invention; 
         FIG. 11  shows a perspective view of a portion of the tail plug of  FIG. 10  in accordance with an embodiment of the invention; 
         FIG. 12  shows a perspective view of an illustrative cable in accordance with an embodiment of the invention; 
         FIG. 13  shows a cross-sectional view of the cable of  FIG. 12  in accordance with an embodiment of the invention; 
         FIG. 14A  shows a perspective rear view of an illustrative rear-mold structure in accordance with an embodiment of the invention; 
         FIG. 14B  shows a perspective front view of the rear-mold structure of  FIG. 14A  in accordance with an embodiment of the invention; 
         FIG. 15  shows a cross-sectional view of the rear-mold structure of  FIG. 14A  in accordance with an embodiment of the invention; 
         FIG. 16  shows an illustrative method for constructing a cap sub-assembly in accordance with some embodiments of the invention; 
         FIG. 17  shows an illustrative method for constructing a rear housing sub-assembly in accordance with some embodiments of the invention; 
         FIG. 18  shows an illustrative method for constructing a cable sub-assembly in accordance with some embodiments of the invention; 
         FIG. 19  shows an illustrative general assembly method for constructing an earbud in accordance with some embodiments of the invention; 
         FIG. 20  shows an illustrative alignment apparatus containing an earbud in accordance with some embodiment of the invention; 
         FIG. 21  shows a perspective top view of the earbud of  FIG. 20  along with two illustrative alignment verification devices in accordance with some embodiment of the invention; 
         FIG. 22  shows a perspective side view of the earbud of  FIG. 20  from a vantage point of one of the alignment verification devices of  FIG. 21  in accordance with some embodiments of the invention; and 
         FIG. 23  shows an illustrative method for achieving minimum gap and offset when constructing an earbud in accordance with some embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Non-occluding earbuds and methods for making the same are described below with reference to  FIGS. 1-23 . Earbuds according to embodiments of this invention include a non-occluding housing having a directional sound port offset with respect to a center axis of the earbud. The housing can have an asymmetric shape amenable to in-the-ear retention, but does not form an airtight seal with the user&#39;s ear or ear canal. The absence of an airtight seal may require that volumes within the earbud be specifically tuned (e.g., by specifically shaping the volumes and/or adding material to the volumes) to achieve a desired frequency response. In addition, secondary apertures in the earbud may be further required to achieve desired sound performance. For example, a secondary aperture may serve as a controlled leak port to expose an acoustic pressure within the earbud to the external, surrounding environment. In this aspect, the secondary aperture may be calibrated to modify an acoustic response of the earbud. 
     Embodiments of this invention use a mid-mold structure within the housing to form a portion of a front volume for a driver (e.g., a speaker) of the earbud. The mid-mold may be fixed to an inner surface of the housing and can have its internal cavity shaped to provide a desired front volume for the driver, regardless of the shape of the housing. Embodiments of this invention also use a rear-mold structure within the housing to form a portion of a back volume for the driver of the earbud. The rear-mold may be fixed to an inner surface of the housing and can have its internal cavity shaped to provide a desired back volume for the driver, regardless of the shape of the housing. The rear-mold can be dimensioned to tune a frequency response and improve a bass response of the earphone. For example, the size and shape of the back volume may be dimensioned to achieve a desired frequency response of the earbud. The rear-mold structure can also serve as the termination point of the earbud cable. In addition, earbuds according to embodiments of this invention can be constructed to have a seamless finish even though two or more parts are joined together to form part of the earbud. As will be explained in more detail below, to achieve the seamless finish, the earbuds can be constructed using a zero gap/offset methodology. 
       FIGS. 1A-1C  show several illustrative views of earbud  100  in accordance with an embodiment of the invention. In particular,  FIG. 1A  shows an exploded view,  FIG. 1B  shows a front view, and  FIG. 1C  shows a top view of earbud  100 . Earbud  100  is a non-occluding earbud, and may be included as part of a headset for a portable media player or mobile phone. Non-occluding earbuds are generally designed not to form an airtight seal between the ear (or ear canal) and the outer surface of the earbud. By way of contrast, occluding earbuds are generally designed to fit inside of the user&#39;s ear canal and form a substantially airtight seal. Earbud  100  can include cap  110 , driver seat  120 , driver  130 , terminator  140 , cable  150 , rear housing  160 , and tail plug  170 . 
     As shown, earbud  100  is asymmetrically shaped along at least two orthogonal axes. Directional sound port  111  is positioned offset with respect to center axis  101 . Directional sound port  111  may be offset such that when earbud  100  is placed in a user&#39;s ear, port  111  is positioned to direct sound directly into the user&#39;s ear canal. 
     In addition to directional sound port  111 , the housing of earbud  100  (i.e., cap  110  and rear housing  160 ) may also include several apertures. For example, earbud  100  includes front leak  112 , back vent  163 , and bass ports  164  (although only one bass port  164  is shown). It is understood that earbud  100  can include just one bass port  164 , and in other embodiments, it can include two or more bass ports  164 . These apertures can provide venting for driver  130  and can help to tune the frequency response of earbud  100  over certain frequency ranges. As an example, the size and shape of front leak  112  may be selected to achieve an amount of air leakage found acoustically desirable and that can be consistently maintained not only each time the same user wears the earphone but also between users. Each aperture in the housing of earbud  100  may be designed to provide specific performance. In other words, each aperture is not just a random opening, but instead has been intentionally formed for a particular purpose, namely to change the frequency response of earbud  100  in a way that helps to tune the frequency response and/or provide a consistent bass response amongst the same user and across users. A more detailed explanation of acoustic ports can be found, for example, in U.S. patent application Ser. No. Publication No. 2013/0343594. 
     Internal components of earbud  100  may have apertures that align with the apertures of cap  110  and rear housing  160 . For example, driver seat  120  may include aperture  122  aligned with front leak  112  and tail plug  170  may include apertures  172  aligned with bass ports  164 . Earbud  100  can also include various meshes (e.g., snorkel mesh  181 , front leak mesh  182 , back vent mesh  186 , and bass port mesh  187 ) that cover or fit into a corresponding aperture of earbud  100 . 
     As shown in  FIGS. 1B and 1C , earbud  100  can be constructed to have a seamless housing even though two or more parts are joined together to form part of the earbud. For example, cap  110  and rear housing  160  can be coupled together to provide a substantially seamless housing for earbud  100 . Once cap  110  and rear housing  160  are mated along plane  115 , substantially no offset or gap exists between the two. As a result, the housing of earbud  100  may appear to have a single piece construction. Two-part construction of the housing of earbud  100  may be necessary in order to accommodate the installation of various internal components (e.g., driver seat  120 , driver  130 , and terminator  140 ). 
     A mid-mold structure may be included within earbud  100  to serve several purposes. For example, driver seat  120  is included as part of earbud  100  to help seat driver  130  and form a portion of a front volume for driver  130 . Driver seat  120  may be fixed to an inner surface of cap  110  using any suitable method (e.g., using glue), and may be formed from any suitable material, for example, driver seat  120  may be formed from plastic. Driver seat  120  can be constructed to provide a front volume of any predetermined size, regardless of the shape of cap  110 . As such, driver seat  120  can aid with the acoustical tuning of earbud  100 . For example, driver seat  120  may occupy a majority of the volume of cap  110  in order to improve the high end frequency response of earbud  100 . Driver seat  120  can also aid with mesh retention. Snorkel mesh  181  and front leak mesh  182  may be coupled to cap  110  in any suitable manner (e.g., using an adhesive). Driver seat  120  can provide additional support to snorkel mesh  181  and front leak mesh  182  to keep them pressed against cap  110  and prevent them from being pushed inwards. 
     A rear-mold structure may also be included within earbud  100 . For example, terminator  140  is included as part of earbud  100  to form a portion of a back volume for driver  130 . Terminator  140  may be fixed to an inner surface of rear housing  160  using any suitable method (e.g., using glue), and may be formed from any suitable material, for example, terminator  140  may be formed from plastic. Terminator  140  can be constructed to provide a back volume of any predetermined size, regardless of the shape of rear housing  160 . As such, terminator  140  can aid with the acoustical tuning of earbud  100 . For example, terminator  140  may tune mid-band acoustics of earbud  100 . A more detailed explanation of the acoustic tuning properties of rear-molds can be found, for example, in U.S. Publication No. 2013/0343593. 
     Terminator  140  may be overmolded over a knot (not shown) in one end of cable  150  and effectively terminates cable  150 . The design and implementation of terminator  140  provides enhanced durability of earbud  100 . For example, terminator  140  provides earbud  100  with an increased ability to withstand abrupt pulling of cable  150  relative to the housing of earbud  100 . As used herein, the term “abrupt pull” is intended to refer to a sudden force applied to one component relative to another component. An abrupt pull may result in the separation of one component from another and may ultimately cause damage that prevents the component from functioning as intended. As a result of including terminator  140 , earbud  100  may be able to withstand both a greater number and larger magnitude of abrupt pull events on cable  150 . 
     Tail plug  170  may be included as part of earbud  100  in order to acoustically seal tail  162  of rear housing  160 . By acoustically sealing tail  162 , tail plug  170  ensures that when driver  130  is operating, air from behind driver  130  is forced down tail  162  and out through bass ports  164  of rear housing  160 . Tail plug  170  may be fixed to rear housing  160  using any suitable method. For example, glue may be used to fix skeleton  171  to an inner surface of rear housing  160 . Tail plug  170  may have a two-part construction including skeleton  171  and sealing member  173 . Skeleton  171  and sealing member  173  may be coupled together using any suitable method, for example, they may be coupled using a chemical bond and/or an interference fit. Skeleton  171  may be constructed of a rigid material (e.g., metal) while sealing member  173  may be formed from a pliable material that is operative to create a seal with tail  162  (e.g., silicone). Skeleton  171  may include apertures  172  that align with bass ports  164  to provide an unobstructed pathway for air to escape from rear housing  160  via bass ports  164 . Bass port mesh  187  may be fixed to skeleton  171  in any suitable manner (e.g., using an adhesive) and skeleton  171  can hold bass port mesh  187  in place against an inner surface of rear housing  160 . 
     Earbud  100  can include three sub-assemblies: a cap sub-assembly, which includes cap  110 , driver seat  120 , driver  130 , and meshes  181  and  182 ; a rear housing sub-assembly, which includes rear housing  160 , tail plug  170 , and meshes  186  and  187 ; and a cable sub-assembly, which includes terminator  140  and cable  150 . Although the elements of earbud  100  are described in terms of three sub-assemblies for convenience, it is understood that this grouping of elements is arbitrary and does not imply any inherent limitations of the individual elements. 
       FIGS. 2-4C  show various views of illustrative cap sub-assembly  200  in accordance with some embodiments of the invention. In particular,  FIG. 2  shows an exploded view of cap sub-assembly  200 ,  FIG. 3A  shows a perspective bottom view of cap sub-assembly  200 ,  FIG. 3B  shows a perspective side view of cap sub-assembly  200 ,  FIG. 3C  shows a perspective top view of cap sub-assembly  200 ,  FIG. 4A  shows a cross-sectional view of cap sub-assembly  200 , taken from line A-A of  FIG. 3A ,  FIG. 4B  shows a cross-sectional view of cap sub-assembly  200 , taken from line B-B of  FIG. 3A , and  FIG. 4C  shows a partial cross-sectional view of cap sub-assembly  200 , showing a magnified view of section C from  FIG. 4B . Cap sub-assembly  200  may include cap  210 , driver seat  220 , driver  230 , snorkel mesh  281 , and front leak mesh  282 . The elements of cap sub-assembly  200  may be substantially the same as similarly-numbered elements of earbud  100 , and elements of  FIGS. 2-4C  may have some or all features as similarly-numbered elements of  FIG. 1 . 
     Cap sub-assembly  200  may include cap  210 , which can serve as a housing for the remaining components of cap sub-assembly  200 . Cap  210  may be formed in any suitable manner and may be made from any suitable material. For example, cap  210  may be molded from plastic. Cap  210  may include directional sound port  211 , which serves as the primary pathway for sound waves created by driver  230 . Directional sound port  211  may be designed to direct the sound waves directly into a user&#39;s ear canal. Cap  210  may also include front leak  212 . The placement and size of front leak  212  may be chosen based on acoustic considerations. For example, front leak  212  may be designed such that it provides proper venting for driver  230  and/or such that it tunes a particular frequency range. For example, front leak  212  can affect performance of the higher frequency portion of the frequency response. As a specific example, for a given earbud with a particularly tuned acoustic profile, the larger the size of front leak  212 , the greater the performance of the higher frequency portion. Cap  210  may include features that help it mate with a corresponding rear housing (e.g., rear housing  160  of  FIG. 1 ) to form an external enclosure. As shown in  FIG. 4C , cap  210  may include snap  213 , which is operative to couple with a snap on a rear housing. 
     The size, shape, and position of front leak  212  can be selected to achieve a desired frequency response for a relatively large sample size of the general population. The position of front leak  212  is such that it minimizes the chance it touches the inside of a user&#39;s ear. Thus, front leak  212  is designed to leak within the user ear. The shape and size of front leak  212  can assist in mitigating such touching. For example, as shown, front leak  212  has a oblong shape or oval-like shape (i.e., longer than it is wide). Such a shape can decrease the probability of full coverage. 
     Cap sub-assembly  200  may also include driver seat  220 . Diver seat  220  is a mid-mold structure that can seat driver  230  in a desired position. Driver seat  220  may be fixed to an inner surface of cap  210  (e.g., using glue) and has a cavity to provide front volume  223  for driver  230 . Driver seat  220  can be constructed to provide front volume  223  of any predetermined size and shape, regardless of the shape of cap  210 . Once driver  230  is positioned against driver seat  220 , front volume  223  may be acoustically isolated from a back volume (not shown). Driver seat  220  may include apertures  221  and  222  that align with directional sound port  211  and front leak  212 , respectively. Apertures  221  and  222  can ensure that driver seat  220  does not obstruct sound waves as they travel from front volume  223  through sound port  211  and front leak  212 . Driver seat  220  may also provide support to other components of cap sub-assembly  200 . For example, snorkel mesh  281  and front leak mesh  282  are positioned between driver seat  220  and cap  210 , and driver seat  220  may press meshes  281  and  282  against cap  210 . Driver seat  220  can help hold meshes  281  and  282  in place and ensure that meshes  281  and  282  cannot be pushed into front volume  223 . 
     Cap sub-assembly  200  may include snorkel mesh  281  and front leak mesh  282  to provide aesthetically pleasing external surfaces and protect internal components. Meshes  281  and  282  may be fixed to either cap  210  or driver seat  220  using any suitable method (e.g., using an adhesive). For example, snorkel mesh  281  is fixed to driver seat  220  while front leak mesh  282  is fixed to an inner surface of cap  210 . Meshes  281  and  282  may prevent foreign objects and substances (e.g., debris, dust, and/or water) from entering cap sub-assembly  200  and damaging driver  230  or other components. Cap  210  may be designed such that meshes  281  and  282  are recessed from an external surface of cap  210 . For example, as shown in  FIG. 4A , snorkel mesh  281  and front leak mesh  282  are recessed relative to the perimeter of cap  210 . Recessing meshes  281  and  282  reduces the amount of contact they have with external surfaces and as a result may reduce the buildup of foreign substances (e.g., earwax) on them. 
     Referring now to  FIGS. 5-6B , various views of an illustrative mid-mold structure in accordance with some embodiments of the invention are shown. In particular,  FIG. 5  shows a perspective top view of driver seat  520 ,  FIG. 6A  shows a cross-sectional view of driver seat  520 , taken from line A-A of  FIG. 5 , and  FIG. 6B  shows a cross-sectional view of driver seat  520 , taken from line B-B of  FIG. 5 . Driver seat  520  can be constructed from plastic and may be injection molded. As shown, driver seat  520  may include apertures  521  and  522  that align with corresponding apertures in an earbud housing (e.g., apertures  111  and  112  of  FIG. 1 ). Aperture  521  may include multiple apertures (e.g., apertures  526  and  527 ) to provide adequate passage for sound waves generated by a driver while also enhancing structural integrity. For example, the material between apertures  526  and  527  may provide support for a mesh (e.g., snorkel mesh  181  of  FIG. 1 ) and ensure that the mesh is not dented or forced inwards. Driver seat  520  may include recess  528  around the perimeter of aperture  522  in order to accommodate and help orient a mesh that is placed over aperture  522  (e.g., front leak mesh  182  of  FIG. 1 ). Driver seat  520  may also include recess  525  for receiving a driver (e.g., driver  130  of  FIG. 1 ). Driver seat  520  may include passive alignment features to help properly position it within a corresponding cap (e.g., cap  110  of  FIG. 1 ). For example, driver seat  520  may include “flat” features  524  that align with a corresponding feature in the cap to determine the orientation of driver seat  520  within the cap. Flats  524  may datum against similar features in the cap. 
     Referring now to  FIG. 7 , an exploded view of a mesh assembly in accordance with an embodiment of the invention is shown. Mesh assembly  781  may correspond to snorkel mesh  181  of  FIG. 1  both in terms of shape and construction. Mesh assembly  781  may include cosmetic mesh  782 , which forms a front surface of mesh assembly  781 . Cosmetic mesh  782  may have a metallic coating on its front surface to provide an aesthetically pleasing finish. For example, cosmetic mesh  782  may undergo physical vapor deposition to apply a thin, highly-adhered pure metal or alloy coating to its front surface. As another example, mesh  782  can be a stainless steel mesh. Mesh assembly  781  may include acoustic mesh  784 , which may provide debris protection and water repellency, and a desired impact on sound performance. For example, a specific acoustic resistance value may be chosen for acoustic mesh  784  to properly tune the damping associated with a port mesh assembly  781  is placed over. In this way, a desired overall frequency response may be achieved. Mesh assembly  781  may also include adhesive layer  783  to couple cosmetic mesh  782  to acoustic mesh  784 . Mesh assembly  781  may further include adhesive layer  785  to couple mesh assembly  781  to another element of an earbud (e.g., driver seat  120  of  FIG. 1 ). 
       FIGS. 8, 9A, and 9B  show various views of illustrative rear housing sub-assembly  800  in accordance with some embodiments of the invention. In particular,  FIG. 8  shows an exploded view of rear housing sub-assembly  800 ,  FIG. 9A  shows a cross-sectional view of rear housing sub-assembly  800 , and  FIG. 9B  shows a partial cross-sectional view of rear housing sub-assembly  800 , showing a magnified view of section B from  FIG. 9A . Rear housing sub-assembly  800  may include rear housing  860 , tail plug  870 , back vent mesh  886 , and bass port mesh  867 . The elements of rear housing sub-assembly  800  may be substantially the same as similarly-numbered elements of earbud  100 , and elements of  FIGS. 8, 9A, and 9B  may have some or all features as similarly-numbered elements of  FIG. 1 . 
     Rear housing sub-assembly  800  may include rear housing  860 , which can serve as a housing for the remaining components of rear housing sub-assembly  800 . Rear housing  860  may be formed in any suitable manner and may be made from any suitable material. For example, rear housing  860  may be molded from plastic. Rear housing  860  may include one or more bass ports  864 , which provide a pathway for air to escape from rear housing  860 . Only one bass port  864  is shown in  FIG. 8 . Bass port  864  may be shaped and positioned to enhance a particular frequency response of an earbud (e.g., bass frequencies). For example, the size of bass port(s)  864  can be dimensioned so that its cross-sectional area equals the cross-sectional area of housing  860  at region  861 . This can ensure no back pressure exists between region  861  and bass port(s)  864 . Rear housing  860  may also include back vent  863 . The placement and size of back vent  863  may also be chosen based on acoustic considerations. For example, back vent  863  may be designed such that it provides proper venting for a driver (e.g., driver  130  of  FIG. 1 ) and/or such that it tunes a particular frequency range. Rear housing  860  may include features that help it mate with a corresponding cap (e.g., cap  110  of  FIG. 1 ) to form an external enclosure. As shown in  FIG. 9B , rear housing  860  may include snap  865 , which is operative to couple with a snap on a cap. 
     Rear housing sub-assembly  860  may also include tail plug  870 . Tail plug  870  may have a two-part construction including skeleton  871  and sealing member  873 . Tail plug  870  may be inserted into an opening in the bottom of rear housing  860  to acoustically seal rear housing  860 . As shown in  FIG. 9A , once tail plug  870  is inserted into rear housing  860 , air may not be able to escape past the seal created between sealing member  873  and an interior surface of rear housing  860 . Instead, air from inside rear housing  860  may be forced through bass port  864 . 
     Skeleton  871  may include apertures  872  that align with bass port(s)  864  to provide an unobstructed pathway for air to escape from rear housing  860  via bass ports  864 . The size of apertures  872  can be larger than the size of bass ports  864  to accommodate variations in assembly tolerances. This way, if alignment of skeleton  871  with respect to housing  860  is slightly off its intended alignment, a pathway for air still exists. Additionally, skeleton  871  may help hold bass port mesh  887  in place and ensure that it cannot be pushed into the interior volume of rear housing  860 . Sealing member  873  may include a feature (e.g., protrusion  874 ) that aligns with a notch of bass port mesh  887  (e.g., notch  888 ) to ensure bass port mesh  887  is placed in a desired position. 
     Rear housing sub-assembly  800  may include back vent mesh  886  and bass port mesh  887  to cover back vent  863  and bass port  864 , respectively. Meshes  886  and  887  may provide aesthetically pleasing external surfaces and prevent debris from entering rear housing  860 . Additionally, meshes  886  and  887  may have any desired acoustic resistance values in order to achieve a desired frequency response. Back vent mesh  886  may be fixed to rear housing  860  using any suitable method. For example, back vent mesh may include an adhesive layer similar to that described with respect to mesh assembly  781  that allows back vent mesh  886  to attach to an inner surface of rear housing  860 . Bass port mesh  887  may be fixed to skeleton  871  and/or rear housing  860  using any suitable method. For example, bass port mesh  887  may also include an adhesive layer that allows it to attach to an outer surface of skeleton  871 . 
     Referring now to  FIGS. 10 and 11 , views of an illustrative tail plug in accordance with an embodiment of the invention are shown. In particular,  FIG. 10  shows a cross-sectional view of tail plug  1070  and  FIG. 11  shows a perspective view of a portion of tail plug  1070 . Tail plug  1070  may include skeleton  1071  and sealing member  1073 . The elements of tail plug  1070  may be substantially the same as similarly-numbered elements of earbud  100 , and elements of  FIGS. 10 and 11  may have some or all features as similarly-numbered elements of  FIG. 1 . 
     Tail plug  1070  may include a rigid member, such as skeleton  1071 . Skeleton  1071  may be constructed from any suitable material using any suitable method. For example, skeleton  1071  may be formed by deep drawing metal (e.g., phosphor bronze). Deep drawing facilitates formation of skeleton  1071  with a desired shape and desired features. For example, by deep drawing skeleton  1071 , large apertures  1072  can be achieved in skeleton  1071  for bass considerations. Deep drawing can also facilitate formation of apertures  1075 , as shown in  FIG. 11 . As described below, apertures  1075  may receive corresponding features of sealing member  1073  to provide an interference fit between skeleton  1071  and sealing member  1073 . Once formed, skeleton  1071  may be coated with another material (e.g., nickel and/or chromium) to enhance its corrosion resistance, surface hardness, and/or appearance. For example, skeleton  1071  may be coated with multiple layers of nickel for corrosion resistance, then a thin layer of chromium to promote adhesion of sealing member  1073 . In one embodiment, it may be coated with three layers of nickel and one layer of chromium. 
     In some embodiments, skeleton  1071  may be formed from plastic using a double-shot molding process. In these embodiments, high flow plastics may be used to achieve a desired shot length and thin-walled section. In other embodiments, skeleton  1071  may be formed using an extrusion process followed by the formation of apertures  1072  and  1075  (e.g., the apertures may be laser cut, stamped, or machined). In other embodiments, skeleton  1071  may be formed using a roll forming process followed by seam welding and the formation of apertures  1072  and  1075 . In other embodiments, skeleton  1071  may be die cast. 
     Tail plug  1070  may also include a compliant member, such as sealing member  1073 . Sealing member  1073  may be constructed from any suitable material. For example, sealing member  1073  may be made from silicone due to its inert nature and ability to withstand attacks from foreign substances (e.g., oils). Sealing member  1073  may have features that help it seal a corresponding tail of a rear housing. For example, sealing member  1073  is formed with features  1074  that follow a contour of a corresponding rear housing (e.g., rear housing  160  of  FIG. 1 ) and provide a desired interference fit between sealing member  1073  and the rear housing. 
     Skeleton  1071  and sealing member  1073  may be coupled in any suitable manner. For example, sealing member  1073  may be overmolded over a portion of skeleton  1071 . Prior to overmolding sealing member  1073 , a primer may be applied to skeleton  1071 . The primer provides a chemical between skeleton  1071  and sealing member  1073 . During the overmolding process, portions of sealing member  1073  may fill apertures  1075 . Apertures  1075  may interact with sealing member  1073  to provide an interference fit and help retain sealing member  1073  to skeleton  1071 . Thus, even if delamination occurs, the interaction between apertures  1075  and sealing member  1073  can hold skeleton  1071  and sealing member  1073  together. 
     During assembly, glue may be disposed within the interior of housing  860  and tailplug  870  is inserted into the opening at the bottom of housing  860 . The glue can encapsulate skeleton  871  and bond it to the interior surface of housing  860 . 
       FIGS. 12 and 13  show various views of an illustrative cable for use in a cable sub-assembly in accordance with some embodiments of the invention. In particular,  FIG. 12  shows a perspective view of cable  1250  and  FIG. 13  shows a cross-sectional view of cable  1250 . Cable  1250  may include cable jacket  1251 , bundle  1252 , and knot  1253 . Cable  1250  may correspond to cable  150  of  FIG. 1  and may have some or all features as similarly-numbered elements of  FIG. 1 . 
     Cable  1250  may include a bundle of conductor wires, such as bundle  1252 . Bundle  1252  may include several tensile members  1255  that run through bundle  1252  and improve the tensile strength of cable  1250 . Tensile members  1255  may be constructed from any suitable material, including, but not limited to, Zylon, Kevlar, Nomex, or Technora. Conductor wires  1254  may be wrapped around some of tensile members  1255  in order to create mini-bundles (e.g., mini-bundles  1256  and  1257 ). Mini-bundles may include a single layer of conductor wires (e.g., mini-bundle  1256 ) or a double layer of conductor wires (e.g., mini-bundle  1257 ). The mini-bundles and tensile members of bundle  1252  may have any suitable arrangement. For example, they may have the “flower” shape shown in  FIG. 13 . 
     Cable  1250  may include cable jacket  1251  to protect other components (e.g., bundle  1252 ) of cable  1250 . Cable jacket  1251  may be constructed from any suitable material and may be formed in any suitable manner. For example, cable jacket  1251  may be extruded from plastic. Cable jacket  1251  may have any suitable inner cross-section for accommodating bundle  1252  (e.g., circular or flower shaped). 
     Cable  1250  may also include knot  1253 . Knot  1253  may be formed by tying the mini-bundles of bundle  1252  into a figure-eight. Knot  1253  may be located a predetermined distance from cable jacket  1251  and may help determine the location of a rear-mold structure (not shown) as described below with respect to  FIGS. 14A-15 . 
     Referring now to  FIGS. 14A, 14B, and 15 , views of an illustrative rear-mold structure are shown in accordance with some embodiments of the invention. In particular,  FIG. 14A  shows a perspective rear view of terminator  1440 ,  FIG. 14B  shows a perspective front view of terminator  1440 , and  FIG. 15  shows a cross-sectional view of terminator  1440 . The elements of terminator  1440  may be substantially the same as similarly-numbered elements of earbud  100 , and elements of  FIGS. 14A-15  may have some or all features as similarly-numbered elements of  FIG. 1 . For purposes of illustration and not of limitation, terminator  1440  is shown overmolded over cable  1250  of  FIGS. 12 and 13 . 
     Terminator  1440  may be constructed from any suitable material and may be formed in any suitable manner. For example, terminator  1440  may be molded from plastic. Terminator  1440  may be overmolded over the end of a cable (e.g., cable  1250  of  FIG. 12 ) and may envelop a portion of the cable. For example, as shown in  FIG. 15 , terminator  1440  may envelop knot  1253  as well as portions of bundle  1252  and cable jacket  1251 . Overmolding terminator  1440  over a cable may serve to “terminate” the cable. As a result, terminator  1440  may secure the cable within a housing of an earbud (e.g., rear housing  160  of earbud  100 ) and prevent the cable from being separated from the housing. During the overmolding process, an end of the cable (e.g., an end including a knot) may be positioned in a predetermined location within a mold in order to ensure that terminator  1440  is formed in a desired location and with a desired orientation. In some embodiments, prior to molding terminator  1440 , a plastic insert (not shown) can be loaded in the mold to help hold the cable in a desired location and to improve the integrity of terminator  1440 . 
     In addition to terminating a cable, terminator  1440  may also define a desired rear volume for a driver of an earbud (e.g., driver  130  of earbud  100 ). Terminator  1440  may include cavity  1443  that can provide a rear volume of a predetermined size and shape, regardless of the shape of a housing that terminator  1440  is located in. Cavity  1443  may have any suitable shape and finish. For example, cavity  1443  may have a hemispherical shape with a smooth finish as shown in  FIG. 14B . Terminator  1440  may also include port  1441  and cutout  1442 . Port  1441  may allow air from behind a driver to flow along a desired path. Along with cavity  1443 , cutout  1442  may further define a desired shape for the rear volume. In addition, cutout  1442  can provide access to a bundle of a cable (e.g., bundle  1252  of cable  1250 ) so that the bundle may be coupled to the driver. As a result of its size and shape, terminator  1440  can aid with the acoustical tuning of an earbud (e.g., earbud  100  of  FIG. 1 ). For example, port  1441  may tune mid-band frequency response of the earbud. 
     Turning now to  FIG. 16 , an illustrative method for constructing a cap sub-assembly in accordance with some embodiments of the invention is shown. Method  1600  may begin at step  1602 . At step  1602 , a first mesh assembly (e.g., snorkel mesh  181  of  FIG. 1 ) may be secured to a driver seat (e.g., driver seat  120  of  FIG. 1 ) using any suitable method. For example, the first mesh assembly may be fixed to the driver seat using a pressure sensitive adhesive. The first mesh assembly may be similar to mesh assembly  781  of  FIG. 7  and may share some or all features of mesh assembly  781 . For example, the first mesh assembly may include an adhesive layer that facilitates attaching it to the driver seat. 
     At step  1604 , a second mesh assembly (e.g., front leak mesh  182  of  FIG. 1 ) may be attached to a cap (e.g., cap  110  of  FIG. 1 ) using any suitable method. For example, the second mesh assembly may be fixed to the cap using an adhesive. Similar to the first mesh assembly, the second mesh may also include an adhesive layer that facilitates attaching it to the cap. 
     At step  1606 , the driver seat may be assembled to the cap using any suitable method. For example, glue may be applied to an inner surface of the cap and/or to an outer surface of the driver seat, and the driver seat may by inserted into the cap. In embodiments that use glue, the driver seat may need to be held in place until the glue cures. The shape of the driver seat along with passive alignment features (e.g., as described with respect to  FIG. 5 ) may ensure that the driver seat is positioned within the cap in a desired orientation. 
     At step  1608 , a driver (e.g., driver  130  of  FIG. 1 ) may be coupled to the driver seat using any suitable method. For example, the cap containing the driver seat may be located in a cap nest (e.g., as described below with respect to  FIGS. 20-23 ), and the cap nest may contain a magnet. The magnet in the cap nest may hold the driver against the driver seat and the cap (e.g., the magnet in the cap nest may attract a magnet in the driver). Thus, the resulting cap sub-assembly may be held in place by the magnet in the cap nest until the cap sub-assembly can be assembled with a cable sub-assembly and a rear housing sub-assembly to form an earbud (e.g., as described below with respect to  FIG. 23 ). Using a magnet may allow the cap sub-assembly to be held in place without using any adhesives that could potentially damage a sensitive diaphragm system of the driver. 
     Illustrative method  1600  has been described for purposes of illustration. A person skilled in the art will appreciate that one or more steps of method  1600  can be altered or rearranged without deviating from the scope of method  1600 . For example, step  1604  may be performed before step  1602 . As another example, the first mesh assembly could be assembled to the cap in step  1602  and/or the second mesh assembly could be assembled to the driver seat in step  1604 . 
     Referring now to  FIG. 17 , an illustrative method for constructing a rear housing sub-assembly in accordance with some embodiments of the invention is shown. Method  1700  may begin at step  1702 . At step  1702 , a first mesh assembly (e.g., bass port mesh  187  of  FIG. 1 ) may be secured to a tail plug (e.g., tail plug  170  of  FIG. 1 ) using any suitable method. For example, the first mesh assembly may be fixed to the tail plug using a pressure sensitive adhesive. The first mesh assembly may be similar to mesh assembly  781  of  FIG. 7  and may share some or all features of mesh assembly  781 . For example, the first mesh assembly may include an adhesive layer that facilitates attaching it to the tail plug. As described with respect to  FIG. 8 , the tail plug may include a feature that aligns the first mesh assembly in a desired position. 
     At step  1704 , a second mesh assembly (e.g., back vent mesh  186  of  FIG. 1 ) may be attached to a rear housing (e.g., rear housing  160  of  FIG. 1 ) using any suitable method. For example, the second mesh assembly may be fixed to an inner surface of the rear housing an adhesive. Similar to the first mesh assembly, the second mesh may also include an adhesive layer that facilitates attaching it to the rear housing. 
     At step  1706 , the tail plug may be assembled to the rear housing any suitable method. For example, glue may be applied to an inner surface of the rear housing and/or to an outer surface of the tail plug, and the tail plug may by inserted into the rear housing. A person skilled in the art will appreciate that one or more steps of method  1700  can be rearranged without deviating from the scope of method  1700 . For example, step  1704  may be performed before step  1702 . 
       FIG. 18  shows an illustrative method for constructing a cable sub-assembly in accordance with some embodiments of the invention. Method  1800  may begin at step  1802 . At step  1802 , all mini-bundles of a cable (e.g., cable  150  of  FIG. 1 ) may be tied into a knot (e.g., a figure-eight knot). The knot may be tied at a predetermined distance from a cable jacket of the cable. 
     At step  1804 , the knot and cable may be fed through a rear housing sub-assembly (e.g., rear housing sub-assembly  800  of  FIG. 8 ). For example, the knot may be inserted through a tail plug hole of the rear housing sub-assembly and fed through the sub-assembly until the knot emerges from a second opening in the sub-assembly. To make feeding the knot and cable through the rear housing sub-assembly easier, a small amount of lubricant may be applied to a portion of the cable (e.g., to an exterior surface of the cable jacket). The knot and cable may be fed through the rear housing sub-assembly until a predetermined amount of the cable passes through the rear housing sub-assembly. 
     At step  1806 , heat shrink may be assembled over the mini-bundles of the cable above the knot. The heat shrink may provide electrical insulation, protection from dust, solvents and other foreign materials, as well as strain relief. 
     At step  1808 , a terminator (e.g., terminator  140  of  FIG. 1 ) may be overmolded over the knot, cable, and heat shrink using any suitable method. For example, the terminator may be injection molded using plastic. The terminator may determine cable matching (e.g., left and right cable matching of two separate earbuds), and as a result the terminator may be overmolded in a precise location/orientation. 
     Referring now to  FIG. 19 , an illustrative general assembly method for constructing an earbud in accordance with some embodiments of the invention is shown. Method  1900  may begin at step  1902 . At step  1902 , a cap sub-assembly (e.g., cap sub-assembly  200  of  FIG. 2 ) may be assembled using any suitable method. For example, the cap sub-assembly can be constructed using method  1600  as described with respect to  FIG. 16 . 
     At step  1904 , a rear housing sub-assembly (e.g., rear housing sub-assembly  800  of  FIG. 8 ) may be assembled using any suitable method. For example, the rear housing sub-assembly can be constructed using method  1700  as described with respect to  FIG. 17 . 
     At step  1906 , a cable sub-assembly may be constructed using any suitable method. For example, the cable sub-assembly can be constructed using method  1800  as described with respect to  FIG. 18 . 
     At step  1908 , the cable sub-assembly may be secured to the rear housing sub-assembly using any suitable method. For example, assembling the cable sub-assembly to the rear housing sub-assembly may include applying glue to an inner surface of the rear housing sub-assembly and/or an outer surface of the cable sub-assembly and attaching the cable sub-assembly to the rear housing sub-assembly. 
     At step  1910 , the cap sub-assembly may be coupled to the rear housing sub-assembly using any suitable method. For example, coupling the cap sub-assembly to the rear housing sub-assembly can be accomplished by following a zero gap/offset methodology as described below with reference to  FIG. 23 . 
     To achieve final assembly of an earbud with a desired alignment (e.g., minimum gap and offset as described below with respect to  FIG. 23 ) specially designed equipment may be required.  FIGS. 20-22  show views of equipment that may be used in combination with method  2300  of  FIG. 23  such that zero gap and offset between a cap and a rear housing of an earbud can be achieved. In particular,  FIG. 20  shows an illustrative alignment apparatus containing an earbud in accordance with some embodiments of the invention,  FIG. 21  shows a perspective top view of the earbud of  FIG. 20  along with two illustrative alignment verification devices in accordance with some embodiments of the invention, and  FIG. 22  shows a perspective side view of the earbud of  FIG. 20  from a vantage point of one of the alignment verification devices of  FIG. 21  in accordance with some embodiments of the invention. 
     As shown in  FIG. 20 , alignment device  2000  may include fixture nests (e.g., cap nest  2001  and rear housing nest  2002 ) for holding an earbud. Cap nest  2001  may hold cap  2010  of the earbud while rear housing nest  2002  may hold rear housing  2060  of the earbud. Nests  2001  and  2002  may be constructed from any suitable material. For example, nests  2001  and  2002  may be made from a non-marking plastic that will not damage or mark-up outer surfaces of cap  2010  or rear housing  2060 . In addition, nests  2001  and  2002  may include elements that help secure cap  2010  or rear housing  2060 , respectively. For example, cap nest  2001  may include a magnet (not shown) that interacts with a magnet of a driver (not shown). The magnet within cap nest  2001  may attract the driver and effectively “sandwich” cap  2010  between cap nest  2001  and the driver. 
     Alignment device  2000  may also include an x-y stage (e.g., x-y stage  2003 ) for aligning cap  2010  and rear housing  2060 . For example, rear housing nest  2002  may be held stationary while cap nest  2001  may move relative to rear housing nest  2002 . Alignment control  2004  may determine x-axis positioning of cap nest  2001  (e.g., by turning alignment control  2004  clockwise or counterclockwise) while alignment control  2005  may determine y-axis positioning of cap nest  2001  (e.g., by turning alignment control  2005  clockwise or counterclockwise). A user may adjust alignment controls  2004  and  2005  until a desired alignment between cap  2010  and rear housing  2060  is achieved. In some embodiments, alignment device  2000  may include an alignment control (not shown) that allows an operator to adjust “clocking” (i.e., rotation of cap  2010  relative to rear housing  2060 ). 
     Alignment device  2000  may exert a mating force on cap  2010  and rear housing  2060  to help force them together during an alignment process (e.g., method  2300 ). For example, alignment device  2000  may include springs (not shown) that attach to rear housing nest  2002  and baseplate  2006 . The springs may pull on rear housing nest  2002  such that they exert a force in the direction of arrow C on rear housing  2060 . The force may be any suitable magnitude, including, for example, 30 Newtons. The force may ensure that cap  2010  and rear housing  2060  remain mated during the alignment process. In some embodiments, alignment device  2000  may include a pressing plate (not shown) that is used to apply force to either cap nest  2001  or rear housing nest  2002 . 
     Turning now to  FIG. 21 , alignment verification devices (e.g., alignment verification devices  2101  and  2102 ) may be used in conjunction with alignment device  2000  to assess the alignment of an earbud. For clarity,  FIG. 21  is shown without alignment device  2000 . Alignment verification devices  2101  and  2102  may be any suitable devices that provide adequate observation of the earbud. For example, alignment verification devices  2101  and  2102  may be charge-coupled devices (CCD) that provide digital imaging of the earbud. As another example, alignment verification devices  2101  and  2102  may be laser measurement instruments. Alignment verification device  2101  may have field of view (FOV)  2103  that observes a first point of the earbud (e.g., point A of  FIG. 20 ) while alignment verification device  2102  may have FOV  2104  that observes a second point of the earbud (e.g., point B of  FIG. 20 ). The first and second points may have any suitable relationship to each other. For example, the first and second points may be offset from each other by 90 degrees. Referring briefly to  FIG. 22 , the view from alignment verification device  2101  is shown. Dimension  2201  may represent the offset between cap  2010  and rear housing  2060  while dimension  2202  may represent the gap between cap  2010  and rear housing  2060 . A user may use information provided by alignment verification devices  2101  and  2102  (e.g., gap and offset information) to adjust alignment device  2000  and achieve a desired alignment of cap  2010  and rear housing  2060 . In some embodiments, an additional alignment verification device (not shown) may be included to view the clocking angle of cap  2010  and rear housing  2060 . In these embodiments, the alignment verification device may observe a parting line on each of cap  2010  and rear housing  2060 . 
     Referring now to  FIG. 23 , an illustrative method for achieving minimum gap and offset when constructing an earbud in accordance with some embodiments of the invention is shown. Method  2300  may begin at step  2302 . At step  2302 , a cap sub-assembly (e.g., cap sub-assembly  200  of  FIG. 2 ) may be mated to a rear housing sub-assembly (e.g., rear housing sub-assembly  800  of  FIG. 8 ). The mating process may include applying glue to a back surface of a driver (e.g., driver  130  of  FIG. 1 ) and/or a cap (e.g., cap  110  of  FIG. 1 ) of the cap sub-assembly. The glue may be any suitable type of glue. For example, the glue may be a hot-melt glue that remains pliable until it cools. The glue may be applied around the entire periphery of the driver and/or cap such that it seals an acoustic chamber that exists between the driver and cap. The mating process may also include soldering mini-bundles of a cable (e.g., cable  150  of  FIG. 1 ) to the driver. The mating process may further include snapping the cap to a rear housing of the rear housing sub-assembly. 
     At step  2304 , constant gap-closing pressure may be applied to the cap and rear housing sub-assemblies. Gap-closing pressure may be applied using any suitable method or apparatus. For example, gap-closing pressure may be applied using an alignment device similar to alignment device  2000  of  FIG. 20 . Before step  2302 , the cap and rear housing sub-assemblies may be loaded into fixture nests (e.g., cap nest  2001  and rear housing nest  2002  of  FIG. 20 ) and the alignment device may apply the gap-closing pressure. The constant gap-closing pressure may be any suitable magnitude. For example, the gap-closing pressure may be 30 Newtons. 
     At step  2306 , the cap and rear housing sub-assemblies may be aligned. The alignment process may be completed using any suitable method or apparatus. For example, the alignment process may be achieved using an alignment device similar to alignment device  2000  of  FIG. 20 . A user may adjust the positioning of the cap and rear housing sub-assemblies relative to each other using the alignment device. The alignment device may include an x-y stage that facilitates movement of either the cap sub-assembly or the rear housing sub-assembly while the other remains stationary. Using the alignment device, the user may adjust the position of the cap sub-assembly or the rear housing sub-assembly until the gap and offset between the sub-assemblies are minimized. In order to verify that both the gap and offset have been minimized, the user may utilize alignment verification devices similar to alignment verification devices  2101  and  2102  of  FIG. 21 . The alignment verification devices may be positioned to look at two tangent points of the cap and rear housing sub-assemblies. The tangent points may have any suitable relationship to one another. For example, the tangent points may be offset by 90 degrees. Once the user determines that the gap and offset between the cap and rear housing sub-assemblies have been minimized, the alignment process may conclude. In some embodiments, the alignment process may include rotating the cap and rear housing sub-assemblies until a desired clocking is achieved. In these embodiments, an additional alignment verification device may be used to observe a parting line on each of the cap and rear housing sub-assemblies. 
     At step  2308 , the alignment process may be complete and the constant gap-closing pressure may be released. In embodiments that use a hot-melt glue, the gap-closing pressure may need to be applied until the hot-melt glue cools to room temperature. In these embodiments, release of the gap-closing pressure may be based on a predetermined length of time. 
     The previously described embodiments are presented for purposes of illustration and not of limitation. It is understood that one or more features of an embodiment can be combined with one or more features of another embodiment to provide apparatus and/or methods without deviating from the spirit and scope of the invention. It will also be understood that various directional and orientational terms are used herein only for convenience, and that no fixed or absolute directional or orientational limitations are intended by the use of these words. For example, the devices of this invention can have any desired orientation. If reoriented, different directional or orientational terms may need to be used in their description, but that will not alter their fundamental nature as within the scope and spirit of this invention. Those skilled in the art will appreciate that the invention can be practiced by other than the described embodiments, which are presented for purposes of illustration rather than of limitation, and the invention is limited only by the claims which follow.

Metadata:
Filing Date: 20120907
Publication Date: 20170718
Grant Date: 20170718
Priority Date: 20120620
Inventors: ZORKENDORFER RICO
HOENIG JULIAN
AASE JONATHAN
STIEHL KURT
HOBSON PHILLIP MICHAEL
WANG ERIC
DAVISON IAN
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R2201/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/2811", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2201/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2201/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2811", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/2811", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 49774492