PATENT DOCUMENT

Publication Number: US-9654863-B2
Application Number: US-201414563990-A
Country: US
Kind Code: B2

Title: Main logic board with mounted speaker and integrated acoustic cavity

Abstract:
A computer system having a loudspeaker mounted on a main logic board by a hermetic seal, is disclosed. More particularly, embodiments of the computer system include an acoustic cavity defined between the loudspeaker, the main logic board, and the hermetic seal. Embodiments of the computer system may include a compressible seal separated from the hermetic seal by the loudspeaker and/or the main logic board. The compressible seal may define an acoustic channel and the loudspeaker may emit sound in a high frequency range through the acoustic channel toward a system exit. Other embodiments are also described and claimed.

Claims:
What is claimed is: 
     
       1. A computer system, comprising:
 a top case having one or more openings; 
 a main logic board below the top case, the main logic board having a substrate coupled with a processor and a memory; and 
 a loudspeaker having a diaphragm movably connected with a speaker housing, wherein the diaphragm is configured to emit sound axially toward the one or more openings, and wherein the speaker housing is bonded to the substrate to form a hermetic joint extending axially between a bottom surface of the speaker housing and the substrate, and traversing a closed path around an acoustic cavity defined between the diaphragm, the speaker housing, the hermetic joint, and the substrate. 
 
     
     
       2. The computer system of  claim 1 , wherein the hermetic joint comprises a solder joint. 
     
     
       3. The computer system of  claim 1 , wherein the hermetic joint comprises a non-conductive adhesive joint. 
     
     
       4. The computer system of  claim 1  further comprising a compressible seal between the loudspeaker and the top case, wherein the speaker housing separates the compressible seal from the hermetic joint, and wherein the compressible seal defines an acoustic channel extending between the diaphragm and the one or more openings. 
     
     
       5. The computer system of  claim 4 , wherein the compressible seal extends from the substrate to the top case. 
     
     
       6. The computer system of  claim 4 , wherein the compressible seal extends from a top surface of the speaker housing to the top case. 
     
     
       7. The computer system of  claim 4  further comprising one or more acoustic ports formed through the substrate and located radially inward from the hermetic joint. 
     
     
       8. The computer system of  claim 7 , wherein the one or more openings in the top case have a first cumulative cross-sectional area, wherein the one or more ports through the substrate have a second cumulative cross-sectional area, and wherein the first cumulative cross-sectional area is less than ten times the second cumulative cross-sectional area. 
     
     
       9. The computer system of  claim 8  further comprising a back casing below the one or more ports, wherein the back casing is coupled with the substrate such that a casing cavity is defined between the back casing and the substrate. 
     
     
       10. The computer system of  claim 9 , wherein the acoustic cavity is acoustically coupled with the casing cavity through the one or more ports. 
     
     
       11. The computer system of  claim 10 , wherein a back volume of the loudspeaker includes the acoustic cavity above the substrate and the casing cavity below the substrate. 
     
     
       12. The computer system of  claim 11 , wherein the loudspeaker includes a magnetic structure above the substrate in the acoustic cavity, and wherein the magnetic structure includes a channel extending from the acoustic cavity to the one or more ports. 
     
     
       13. The computer system of  claim 12 , wherein the magnetic structure includes a stack having a top plate, a permanent magnet, and a yoke, and wherein the channel extends through the stack. 
     
     
       14. The computer system of  claim 13  further comprising one or more devices mounted to the substrate in the casing cavity, wherein the back casing is configured to shield the one or more devices. 
     
     
       15. The computer system of  claim 7 , wherein the diaphragm is movably connected with the substrate directly, such that a surround of the loudspeaker is directly attached to the substrate. 
     
     
       16. The computer system of  claim 7 , wherein a front volume of the loudspeaker includes the acoustic channel above the substrate and the acoustic cavity below the substrate. 
     
     
       17. The computer system of  claim 4 , wherein the diaphragm is movably connected with a first edge of the speaker housing at a first location and a second edge of the speaker housing is connected with the substrate by the hermetic joint at a second location radially outward from the first location. 
     
     
       18. A computer system comprising:
 an external housing having a top face and a bottom face, the top face having a sound output opening formed therein; 
 a circuit board within the external housing, the circuit board having a plurality of electronic hardware components installed on a circuit carrier; 
 a loudspeaker bonded to the circuit carrier, the loudspeaker having a speaker housing, a diaphragm that movably connects to the speaker housing and is acoustically coupled to the sound output opening in the top face of the external housing through an acoustic channel that is part of a front volume of the loudspeaker; and 
 a hermetic joint that seals a gap between the speaker housing and the circuit carrier to create an acoustic cavity defined by the diaphragm, the speaker housing, the hermetic joint, and the circuit carrier, the acoustic cavity being part of a back volume of the loudspeaker, wherein the hermetic joint extends axially between a bottom surface of the speaker housing and the circuit carrier, and traversing a closed path around the acoustic cavity. 
 
     
     
       19. A computer system, comprising:
 a system housing having a ceiling, a floor, and an internal volume between the ceiling and the floor; 
 a circuit board in the internal volume, the circuit board having a substrate coupled with a processor and a memory; and 
 a loudspeaker having a diaphragm movably connected with a speaker housing, wherein the loudspeaker divides the internal volume into a front volume between the ceiling and the diaphragm and a back volume between the floor and the diaphragm, wherein the speaker housing is coupled with the ceiling by a compressible seal that defines an acoustic channel in the front volume between the diaphragm and the ceiling, and wherein the speaker housing is bonded to the substrate to form a hermetic joint extending axially between a bottom surface of the speaker housing and the substrate, and traversing a closed path around an acoustic cavity in the back volume between the diaphragm and the floor. 
 
     
     
       20. The computer system of  claim 19 , wherein the speaker housing is shaped such that the acoustic cavity is a desired volume between the diaphragm, the speaker housing, the hermetic joint, and the substrate.

Description:
BACKGROUND 
     Field 
     Embodiments related to an electronics device having a loudspeaker mounted on a main logic board are disclosed. More particularly, an embodiment related to a computer system having a loudspeaker bonded to a main logic board by a hermetic seal that partially defines an integrated acoustic cavity is disclosed. 
     Background Information 
     A portable consumer electronics device, such as a laptop computer, typically includes a system enclosure surrounding internal system components and devices. The internal system components generally include a primary circuit board, e.g., a motherboard, and one or more audio speakers for outputting audio. These internal system components must share the limited space within the system enclosure. Furthermore, the motherboard generally includes many layers of components, including integrated circuits, passive devices, etc., which crowd the spaces above and below the motherboard. Thus, the audio speakers have ordinarily been located to a side of the motherboard so that the speaker can be as tall as the entire vertical space within the system enclosure, rather than sharing the vertical space with the motherboard. This can allow more of the vertical space to be used for both the speaker driver and the back volume of the audio speaker to thereby provide desirable low frequency audio output. 
     SUMMARY 
     Portable consumer electronics devices, such as laptop computers, have continued to become more and more compact. As system enclosures become smaller, the space available for speaker integration to a side of a primary circuit board, also referred to here as a main logic board, diminishes. As described below, rather than occupying a space lateral to the main logic board, system speakers may be moved onto the main logic board. For example, one or more of the speakers, such as a high frequency restricted “tweeter” device, may be mounted on the main logic board to occupy or share the same vertical space within the system enclosure as the main logic board. However, a speaker requires adequate back volume to produce acceptable sound quality within a designed—for audio range. Thus, computer systems are disclosed that mount a loudspeaker to the main logic board such that a back volume is integrated between the loudspeaker and the main logic board to generate an additional volume. 
     A computer system may include a system housing having a top case with an integrated opening, as well as a bottom case. A main logic board within the system housing may be located below the top case (and above the bottom case), and may include a circuit carrier or a substrate to which are coupled one or more electronic components, e.g., a processor and/or a memory. In an embodiment, a loudspeaker is attached to the main logic board by a hermetic seal. The loudspeaker may be an electrodynamic driver, and thus, may have a diaphragm that is movably connected with a speaker housing or frame to emit sound toward the opening in the top case. For example, the loudspeaker may be a tweeter configured to emit sound in a range higher than 1,500 Hz. The speaker housing or frame may be coupled with the substrate by the hermetic seal such that an acoustic cavity is defined between the diaphragm, the speaker housing, the hermetic seal, and the substrate. For example, the hermetic seal may include a solder joint or an adhesive joint that attaches the speaker housing to the substrate along a closed path surrounding the acoustic cavity. 
     In an embodiment, the speaker housing is shaped to form the acoustic cavity such that an additional volume and thus a low frequency output is obtained. For example, the speaker housing may include a first edge to which the diaphragm is movably connected at a first location and a second edge connected with the substrate by the hermetic seal at a second location radially outward from the first location. That is, the speaker housing may have a bell-shape, with a predetermined volume to achieve an intended acoustic response. 
     The computer system having an acoustic cavity integrated within the hermetic seal between the loudspeaker and the main logic board may also include a compressible seal between the loudspeaker and the top case of the system housing to direct the emitted sound toward the opening. For example, the compressible seal may define an acoustic channel extending between the diaphragm and the opening such that sound can more efficiently radiate outside the system housing into a surrounding environment, rather than leak into a lateral space within the system housing. For example, in an embodiment, the compressible seal extends from the circuit carrier or substrate to the top case. In another embodiment, the compressible seal extends only from a top surface of the speaker housing to the top case. Thus, the speaker housing may separate the compressible seal from the hermetic seal such that the respective seals define different volumes in the speaker assembly, e.g., a front volume and a back volume of the speaker assembly. 
     In an embodiment, the computer system includes a through hole or port formed through the substrate that is radially positioned inward from the hermetic seal. The opening through the top case may have a first cumulative cross-sectional area, and the port may have a second cumulative cross-sectional area, and together these may be sized to provide the desired acoustic effects. For example, the second cumulative cross-sectional area of the port or substrate opening could be sized such that acoustic resistance is provided to the driver to mitigate acoustic resonances. 
     A back casing may be located below the port to form a second chamber of a multi-chamber back volume of the speaker assembly. For example, the back casing may be mounted on an underside of the substrate such that a casing cavity is defined between the back casing and the substrate, between the main logic board and bottom case. Thus, the acoustic cavity defined between the diaphragm, the speaker housing, the hermetic seal, and the substrate may be acoustically coupled with the casing cavity through the port. Accordingly, the speaker assembly has a multi-chambered back volume that includes the acoustic cavity or chamber above the substrate and the casing cavity below the substrate. The multi-chamber back volume may provide a desirable low frequency output. 
     In an embodiment, the loudspeaker includes a magnetic structure as part of a motor assembly to drive the diaphragm. For example, the magnetic structure may include a stack having a top plate, a permanent magnet, and a yoke. The magnetic structure may be located above the substrate and inside of the acoustic cavity. A channel may extend through the stack of the magnetic structure from the acoustic cavity to the port in order to place the acoustic cavity in fluid (acoustic) communication with the casing cavity. The back casing that provides the audio intended casing cavity may also be configured to passively shield an electronic component. For example, the electronic device may be mounted on the substrate in the casing cavity, and the back casing may surround the electronic device to acoustically and/or electrically (electromagnetically) shield the electronic device from interference. Accordingly, a multi-chamber back volume may reduce system noise and boost system performance by shielding main logic board components, such as components that emit noise directly. Furthermore, if system noise arises from substrate vibration, the substrate that forms a portion of the multi-chamber back volume may be stiffened to augment the noise reduction. 
     In an embodiment, the loudspeaker is integrated directly with the main logic board. For example, the diaphragm may be movably connected with the substrate directly, such that a surround of the loudspeaker is directly attached to the substrate (rather than to the loudspeaker housing/frame). In that case, the speaker housing may be attached to the lower face of the substrate at the hermetic seal radially outward from the inner edge. Accordingly, sound may be emitted upward toward the opening in the top case, and a back volume may be defined opposite from the opening by the combination of the diaphragm, the substrate, and the speaker housing. 
     In another embodiment, the speaker assembly may include a multi-chamber front volume. For example, a front volume of the loudspeaker may include an acoustic channel above the substrate and an acoustic cavity below the substrate. More particularly, the speaker housing may be mounted on an underside or lower face of the substrate (extending downward from the underside, as opposed to upward from the top side or upper face), and the diaphragm may be located within the speaker housing below the substrate, such that an acoustic cavity is formed between the diaphragm, the speaker housing, and the underside of the substrate. The port through the substrate may interconnect the acoustic cavity with the acoustic channel above the substrate to form a multi-chamber front volume. 
     The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a computer system. 
         FIG. 2  is a block diagram of electronic components in a computer system. 
         FIG. 3  is a cross-sectional view, taken about line A-A of  FIG. 1 , of a speaker assembly of a computer system in accordance with an embodiment of the invention. 
         FIG. 4  is a cross-sectional view, taken about line B-B of  FIG. 3 , of a loudspeaker mounted on a main logic board in accordance with an embodiment. 
         FIG. 5  is a cross-sectional view, taken about line B-B of  FIG. 3 , of a loudspeaker mounted on a main logic board in accordance with an embodiment. 
         FIGS. 6A-6C  are cross-sectional views, taken about line C-C of  FIG. 5 , of a hermetic seal between a loudspeaker and a main logic board in accordance with an embodiment. 
         FIG. 7  is a cross-sectional view, taken about line A-A of  FIG. 1 , of a speaker assembly of a computer system in accordance with an embodiment. 
         FIG. 8  is a cross-sectional view, taken about line D-D of  FIG. 7 , of a loudspeaker mounted over a main logic board and a back casing mounted below the main logic board in accordance with an embodiment. 
         FIG. 9  is a cross-sectional view, taken about line A-A of  FIG. 1 , of a speaker assembly of a computer system in accordance with an embodiment. 
         FIG. 10  is a cross-sectional view, taken about line E-E of  FIG. 9 , of a loudspeaker mounted under a main logic board in accordance with an embodiment. 
         FIG. 11  is a sectional view of a loudspeaker integrated with a main logic board in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments describe computer systems having a loudspeaker mounted on a main logic board by a hermetic seal. However, while some embodiments are described with specific regard to integration within laptop computer systems, the embodiments are not so limited and certain embodiments may also be applicable to other uses. For example, a speaker assembly as described below may be incorporated into other devices and apparatuses having printed circuit boards and electroacoustic transducers, including desktop computers and portable consumer electronics devices (such as smartphones and tablet computers), to name only a few possible applications. 
     In various embodiments, description is made with reference to the figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions, and processes, in order to provide a thorough understanding of the embodiments. In other instances, well-known processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the description. Reference throughout this specification to “one embodiment,” “an embodiment”, or the like, means that a particular feature, structure, configuration, or characteristic described is included in at least one embodiment. Thus, the appearance of the phrase “one embodiment,” “an embodiment”, or the like, in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments. 
     The use of relative terms throughout the description, such as “top” and “bottom” may denote a relative position or direction. For example, a “top case” may be located in a first axial direction from an internal component of a computer system and a “bottom case” may be directed in a second axial direction opposite to the first axial direction. However, such terms are not intended to limit the use of the computer system to a specific configuration described in the various embodiments below. For example, a top case of a computer system may be oriented in a direction parallel to the ground from a loudspeaker in certain applications, such as in the case of a front panel of an automated teller machine. 
     In an aspect, a loudspeaker may be mounted directly on a main logic board such that at least a portion of an acoustic cavity, e.g., a back volume, is defined between the loudspeaker and the main logic board. The loudspeaker may be mounted on the main logic board by hermetically sealing a speaker housing directly to a substrate of the main logic board, e.g., using solder or adhesive. Thus, the acoustic cavity may be partly defined by a closed path of the hermetic seal. The integrated acoustic cavity may enhance audio output, and in an embodiment, sound quality may be further enhanced by providing a compressible seal separate from the hermetic seal. For example, the compressible seal may define an acoustic output channel in a front volume for sound to be directed through openings in the top case toward a surrounding environment. 
     In an aspect, a back volume of a loudspeaker mounted directly on a main logic board may be increased by providing a port through the main logic board from an acoustic cavity over the main logic board to a rear cavity under the main logic board. In an embodiment, a back casing may be hermetically sealed to an underside of the main logic board to create the rear cavity. Thus, the port may acoustically couple a first chamber of a speaker volume above the main logic board with a second chamber of the speaker volume below the main logic board. As such, the chambers may combine to form a back volume of a speaker assembly. 
     In an aspect, a loudspeaker may be mounted directly on a main logic board such that sound is emitted toward the main logic board. For example, a top surface of the loudspeaker may be hermetically sealed to a bottom surface of the main logic board. Thus, an acoustic cavity may be partly defined by a closed path of the hermetic seal in front of a speaker diaphragm. That is, the acoustic cavity may be located between the loudspeaker and an underside of the main logic board. In an embodiment, a port through the main logic board may allow sound to propagate upward toward a top case of a system enclosure. Furthermore, a compressible seal may extend from an upper side of the main logic board to the top case to form an acoustic channel to direct the sound through openings in the top case toward a surrounding environment. As such, the acoustic channel and the acoustic cavity may combine to form multiple chambers of a front volume of a speaker assembly. 
     Referring to  FIG. 1 , a perspective view of a computer system is shown. A computer system  101 , such as a laptop computer, may include a speaker assembly as described below. More particularly, any computer system  101  having a system housing  102  that encloses a loudspeaker and a primary circuit board, such as a main logic board, may include an embodiment of a speaker assembly. Thus, although computer system  101  may be a laptop computer, it may also be a tablet computer, a mobile phone, etc. In any case, computer system  101  may include a system exit  104 , such as a perforation or slots in a keyboard, through which the internal loudspeaker may radiate sound into a surrounding environment. 
     Referring to  FIG. 2 , a block diagram of electronic components in a computer system is shown. Computer system  101  is exemplary, and embodiments of the invention may operate on, or be controlled by, a number of different computer systems including general purpose networked computer systems, embedded computer systems, routers, switches, server devices, client devices, various intermediate devices/nodes, stand-alone computer systems, and the like. In an embodiment, computer system  101  includes an address/data bus  202  for communicating information. For example, computer system  101  may include a main logic board having a processor  204 , e.g., a central processing unit, coupled to bus  202  for processing information and instructions. The main logic board of computer system  101  may also include data storage features such as a main memory  206 , e.g., a computer usable volatile memory such as dynamic random access memory (DRAM), coupled to bus  202  for storing information and instructions for central processing unit  204 . Computer usable non-volatile memory  208 , e.g. read only memory (ROM), may also be coupled to bus  202  and/or mounted on the main logic board for storing static information and instructions for the central processor  204 . In addition to processing and memory hardware, computer system  101  may include various input and output devices. For example, computer system  101  may include an alphanumeric input device  210  and/or cursor control device  212  coupled to bus  202  for communicating user input information and command selections to central processing unit  204 . Likewise, computer system  101  may include a display device  214  coupled to bus  202  for displaying information to a user. In an embodiment, one or more of the input and output devices may be directly mounted on the main logic board. For example, a loudspeaker  216  may be electrically connected to the main logic board and coupled to bus  202 , for receiving an audio signal and in response generating and emitting sound through system exit  104  toward the user. 
     Referring to  FIG. 3 , a cross-sectional view, taken about line A-A of  FIG. 1 , of a speaker assembly of a computer system is shown in accordance with an embodiment of the invention. Computer system  101  may include a speaker assembly  301  to generate and output sound to a user. In an embodiment, speaker assembly  301  includes loudspeaker  216 , and in addition, speaker assembly  301  includes one or more acoustic cavities formed by portions of a system housing  102  and a main logic board  302 . In an embodiment, system housing  102  is a rigid enclosure, e.g., formed from aluminum, and includes a top case  304  and a bottom case  306  creating an internal space within which loudspeaker  216  and main logic board  302  are housed. Each case, i.e., top case  304  and bottom case  306  may form an envelope of system housing  102 . For example, top case  304  may be a ceiling to, and provide a top face for, a volume within system housing  102 . Similarly, bottom case  306  may be a floor to, and provide a bottom face for, the volume within system housing  102 . Main logic board  302  may include a printed circuit board, e.g., a motherboard, having a substrate  310  with one or more layers, e.g., laminated conductive layers separated by non-conductive layers and patterned to form circuit traces that make electrical signal connections between various components that are installed on the substrate  310 , e.g., processor  204 , main memory  206 , audio amplifiers, etc. Speaker assembly  301  may include portions of top case  304  and bottom case  306  above and below loudspeaker  216 . In particular, speaker assembly  301  may include a portion of top case  304  having one or more openings  308  for porting sound generated by loudspeaker  216  to the surrounding environment. A back volume of loudspeaker  216  may be integrated between loudspeaker  216  and substrate  310  of main logic board  302 . For example, loudspeaker  216  may be connected to and/or sealed against substrate  310  of main logic board  302  by a hermetic seal  312 . Thus, a back cavity  311  and an additional volume  313 , which includes an acoustic cavity  314 , may define all or part of a speaker back volume. For example, back cavity  311  may include a volume within loudspeaker  216 , below a diaphragm of loudspeaker  216 . Thus, the back volume may be enclosed between loudspeaker  216 , hermetic seal  312 , and a top surface of substrate  310 . 
     In an embodiment, a front volume may be enclosed above loudspeaker  216  by a compressible seal  316  that extends between loudspeaker  216  and a bottom surface of top case  304 , i.e., a ceiling or top face of the volume within system housing  102 . Thus, sound generated by loudspeaker  216  may be directed through a front cavity  309  portion of the front volume toward openings  308  and into the surrounding environment without propagating into a lateral space  318  within system housing  102 . In an embodiment, other system components and devices such as processor  204  and/or main memory  206  may be mounted on main logic board  302  within lateral space  318 . The other system components may be on the same side as loudspeaker  216 , as shown. Alternatively, the other system components may be on an opposite side of main logic board  302 , e.g., between substrate  310  and a top surface of bottom case  306 , i.e., a floor to or a bottom face of the volume within system housing  102 . 
     Referring to  FIG. 4 , a cross-sectional view, taken about line B-B of  FIG. 3 , of a loudspeaker mounted on a main logic board is shown in accordance with an embodiment. In an embodiment, speaker assembly  301  includes loudspeaker  216  sandwiched between top case  304  of system housing  102  and substrate  310  of main logic board  302 . Loudspeaker  216  may be an electroacoustic transducer designed to reproduce sound in a predetermined audio frequency range. For example, loudspeaker  216  may be a high frequency driver, i.e., a “tweeter”. The tweeter may be configured to emit sound having an audio frequency in a range higher than 1,500 Hz. For example, loudspeaker  216  may generate sounds having an audio frequency in a range higher than 2,000 Hz. Alternatively, loudspeaker  216  may have another driver design, e.g., loudspeaker  216  may be a mid-range driver capable of reproducing sound in a range of 300 to 5,000 Hz. Although the profile dimensions (X,Y) of loudspeaker  216  may vary based on a particular application, in a laptop integration scenario, loudspeaker  216  may have profile dimensions X,Y (when viewed axially in a direction perpendicular to a diaphragm  402 —see  FIG. 6B ) on the order of 30 mm by 30 mm, and in another case on the order of 10 mm by 10 mm. Furthermore, a profile shape of loudspeaker  216  (when viewed in the direction of sound emission) may include any geometry, including circular or rectangular geometries—see  FIGS. 6A-6C . 
     Loudspeaker  216  may include diaphragm  402  surrounded by a speaker housing  404 . More particularly, diaphragm  402  may be movably connected to speaker housing  404  by a speaker surround  406  that flexes to allow diaphragm  402  to move axially with pistonic motion, i.e., forward and backward, relative to speaker housing  404 . The pistonic motion may be imparted to diaphragm  402  by a motor assembly to reproduce a desired sound. For example, diaphragm  402  may be connected to a voicecoil  408  that moves relative to a magnetic structure of the motor assembly. In an embodiment, the magnetic structure includes a stack of magnetic components. For example, a magnet  410  may be attached to a top plate  412  at a front face and to a yoke  414  at a back face. Magnet  410  may include a permanent magnet and both top plate  412  and yoke  414  may be formed from magnetic materials to create a magnetic circuit having a magnetic gap within which voicecoil  408  may oscillate forward and backward. Thus, when an electrical audio input signal is input to voicecoil  408 , a mechanical force may be generated that moves diaphragm  402  relative to the stack of magnetic components to radiate sound forward into a front volume of speaker assembly  301  and through openings  308  into the surrounding environment. 
     In an embodiment, loudspeaker  216  is mounted directly on substrate  310 . For example, speaker housing  404  may be connected to substrate  310  by hermetic seal  312 . Hermetic seal  312  may be formed by bonding speaker housing  404  to substrate  310  using known techniques, such as surface-mount technology. In an embodiment, hermetic seal  312  may run along a lower edge of a wall or face of speaker housing  404  that surrounds a driver, i.e., motor assembly, of loudspeaker  216 . Hermetic seal  312  may extend axially between the wall or face of speaker housing  404  and substrate  310 . Accordingly, loudspeaker  216  may be mounted directly on substrate  310  by using reflow techniques to deposit solder or high temperature plastics to form an airtight joint at hermetic seal  312  between speaker housing  404  and substrate  310 . The joint may mechanically secure speaker housing  404  to substrate  310 , and may also provide an electrical connection between the motor assembly of loudspeaker  216  and bus  202 . For example, a conductive solder may form a portion of an electrical connection between voicecoil  408  and bus  202 . So the hermetic seal  312  need not be completely surrounding the diaphragm  402 ; if conductive, it may form two isolated sections to deliver the audio signal to the voicecoil  408  and return the signal back to the amplifier. For example, the two isolated sections may be two semi-circular seals, e.g., c-shaped seals with the ends of each seal adjacent to a corresponding end of the other seal. Accordingly, the c-shaped seals may be a conductive solder while the gaps between the c-shaped seals may be filled by a non-conductive sealant, e.g., an adhesive, to form a composite circular seal. 
     In an alternative embodiment, hermetic seal  312  may be formed by applying and curing an adhesive, e.g., an epoxy resin, between speaker housing  404  and substrate  310 . The cured epoxy may fasten loudspeaker  216  directly to main logic board  302 . Furthermore, electrical connections between the voicecoil  408  of the loudspeaker  216  and an audio amplifier on the main logic board  302  (not shown) may be formed using, e.g., pins or leads in the speaker housing, which may go through hermetic seal  312  or down through a lower metal trace/conductive layer of the substrate  310 . For example, in an embodiment, through-hole construction may be used, in which pins providing electrical connections to the motor assembly of speaker assembly  301  may be inserted in and soldered to, substrate  310 . An adhesive may be flowed into the remaining gaps around the pins and between speaker housing  404  and substrate  310  to create hermetic seal  312 . Hermetic seal  312  may be formed such that the electrical pins are encapsulated within an epoxy, for example. Thus, hermetic seal  312  may traverse a path that includes airtight portions and/or electrical connections. 
     Loudspeaker  216  may be mechanically and/or electrically connected with main logic board  302  using other known techniques. For example, speaker housing  404  may be secured to substrate  310  at one or more locations by mechanical connectors, such as threaded fasteners, rivets, etc. Electrical connections between voicecoil  408  and bus  202  may be formed by leads, vias, and other known electrical connectors. Thus, while hermetic seal  312  may provide a mechanical and/or electrical connection between loudspeaker  216  and main logic board  302 , other connectors may supplement such connections. 
     In an embodiment, the integration of a speaker back volume between loudspeaker  216  and substrate  310  and the creation of electrical connections between loudspeaker  216  and main logic board  302  may be performed in multiple operations. For example, hermetic seal  312  may be formed in a first operation, e.g., by reflowing solder along a closed path between speaker housing  404  and substrate  310 . Loudspeaker  216  may be electrically connected to bus  202  (or to another electronic component) in a second operation, e.g., by soldering one or more pins of loudspeaker  216  to substrate  310  and/or connecting electrical leads between the two components. In an embodiment, the sealing operation forms an airtight joint along a closed path to form an integrated back volume between loudspeaker  216  and substrate  310 , and to prevent air leakage from the back volume behind the diaphragm  402  to lateral space  318  in the system housing  102  (except for an intentional vent—not shown—that may be added to provide a small air leak so that internal and external pressures can equalize over time to compensate for barometric pressure or altitude changes; an imperfectly sealed enclosure may also be sufficient to provide this slow pressure equalization). For example, hermetic seal  312  may extend around a perimeter of a bottom surface of speaker housing  404  to create acoustic cavity  314 . More particularly, acoustic cavity  314  may be defined between diaphragm  402 , surround  406 , speaker housing  404 , substrate  310 , and motor assembly. Thus, in an embodiment, acoustic cavity  314  provides an entire back volume of speaker assembly  301 . 
     A front volume of speaker assembly  301  may be provided above diaphragm  402 . As diaphragm  402  moves up and down during sound reproduction, sound may travel upward into the front volume, which may be defined between diaphragm  402 , surround  406 , speaker housing  404 , compressible seal  316 , and top case  304 . More particularly, sound may travel upward toward top case  304  through an acoustic channel  416  portion of the front volume. In an embodiment, acoustic channel  416  is that portion of the front volume that is radially inward from compressible seal  316 . For example, compressible seal  316  may be a gasket that fills a gap between a top surface  418  of speaker housing  404  and a bottom surface  420  of top case  304 . For example, compressible seal  316  may run along an upper edge of a wall or face of speaker housing  404  radially outward from diaphragm  402 . Compressible seal  316  may extend axially between the wall or face, e.g., top surface  418 , and ceiling or top face of the system housing, e.g., bottom surface  420 . Thus, compressible seal  316  may be separated from hermetic seal  312  by speaker housing  404 . The gasket may be annular, e.g., cylindrical, creating a cylindrical acoustic channel  416  through which sound propagates on the way from diaphragm  402  to the surrounding environment. It could alternatively have a different annular shape, e.g., elliptical, polygonal, or a combination having some curved portions and some straight portions (see, e.g.,  FIGS. 6A-6C ). In an embodiment, compressible seal  316  is formed from an acoustically rigid material, such as a polyurethane foam, that directs sound forward to openings  308  and/or prevents sound from leaking radially outward from acoustic channel  416  to lateral space  318  within system housing  102 . Thus, in an embodiment, an outer boundary of speaker assembly  301  encompasses a front volume and a back volume defined between top case  304 , compressible seal  316 , speaker housing  404 , hermetic seal  312 , and substrate  310 . 
     Referring to  FIG. 5 , a cross-sectional view, taken about line B-B of  FIG. 3 , of a loudspeaker mounted on a main logic board is shown in accordance with an embodiment. The geometry of the front volume and back volume of speaker assembly  301  may be altered by changing the geometry of those portions of speaker assembly  301  that define the volumes. For example, speaker housing  404  may be designed to provide a predetermined back volume size for obtaining a desired acoustic response. More particularly, speaker housing  404  walls below diaphragm  402  may be shaped to control the dimensions of acoustic cavity  314 . In an embodiment, speaker housing  404  walls may be flared outward (like a bell shape as shown) to enlarge acoustic cavity  314  as compared to the embodiment shown in  FIG. 4 . For example, speaker housing  404  may be bonded to speaker surround  406  at a first location on an edge or surface of a lip  502  feature. Furthermore, speaker housing  404  may be bonded to substrate  310  by hermetic seal  312  at a second location, which may be radially outward from the first location. As such, the walls of speaker housing  404  may form a concave upward shape that defines a portion of acoustic cavity  314 . In particular, the bell-shaped acoustic cavity  314  may have a volume that enhances sound quality of loudspeaker  216  as compared to, e.g., a cylindrical acoustic cavity  314  with a radius defined by the first location at lip  502 . 
     Other embodiments of speaker housing  404  may provide for different sizes of an integrated back volume between speaker housing  404  and substrate  310 . For example, rather than being tapered toward substrate  310  from lip  502 , speaker housing  404  may extend radially outward from speaker surround  406  at lip  502  in a direction parallel to substrate  310 . Then, at a location radially outward from speaker surround  406 , speaker housing  404  may angle downward, e.g., in a tapered manner or perpendicular to substrate  310 . Thus, speaker housing  404  may be sealed against substrate  310  by hermetic seal  312  radially outward from diaphragm  402 . In such case, speaker housing  404  may form a cylindrical cavity below diaphragm  402  and the cavity may have a diameter larger than that of diaphragm  402  to create a back volume that produces a desired low frequency output. 
     Still referring to  FIG. 5 , the front volume of speaker assembly  301  may also be tailored by adjusting the components that define portions of the volume, e.g., acoustic channel  416 . In an embodiment, compressible seal  316  may have a non-annular shape that allows sound to propagate through a side-firing opening  308 . For example, rather than being ring-shaped, compressible seal  316  may have a c-shaped profile, such that sound can propagate sideways through the discontinuity in the c-shape. Thus, in an embodiment, the break in the c-shape of compressible seal  316  is aligned with opening  308  directed toward a side-firing port in system housing  102 , e.g., a perforation in a side panel rather than in top case  304 , such that when diaphragm  402  emits sound upward toward top case  304 , the sound is redirected through acoustic channel  416  of front volume into side-firing opening  308  and radially outward to the surrounding environment. 
     In an embodiment, a side-firing speaker design includes an annular compressible seal  316  that seals entirely around a top surface  418  of speaker housing  404 . In such case, a hole may be formed radially through a wall of speaker housing  404  above diaphragm  402  to allow for sound to be emitted laterally. Thus, the example of a side-firing speaker assembly  301  illustrated in  FIG. 5  is provided by way of example only, and not by way of limitation. 
     Referring now to  FIG. 6A , a cross-sectional view, taken about line C-C of  FIG. 5 , of a hermetic seal between a loudspeaker and a main logic board is shown in accordance with an embodiment. Similar to the manner in which speaker housing  404  and compressible seal  316  may be modified to adjust a back volume and/or front volume of speaker assembly  301 , the contour of hermetic seal  312  may also be altered to control the volume of acoustic cavity  314 . In an embodiment, hermetic seal  312  extends along a closed path within a plane between speaker housing  404  and substrate  310 . Thus, hermetic seal  312  encloses a portion of acoustic cavity  314  that may be defined radially inward from hermetic seal  312 . Accordingly, the defined volume may depend on the cross-sectional area and the thickness of hermetic seal  312 . For example, hermetic seal  312  may extend along a curvilinear path having one or more curvilinear segments  602 . The curvilinear path may be circular and have a thickness that defines a cylindrical portion of acoustic cavity  314 . Accordingly, by altering a diameter of curvilinear segment  602 , or by altering the thickness of hermetic seal  312 , the volume of acoustic cavity  314  enclosed by hermetic seal  312  may be controlled. In an embodiment, the thickness of hermetic seal  312  is in a range on the order of less than 10 mm, and in some cases less than 1 mm. 
       FIG. 6B  illustrates a cross-sectional view, taken about line C-C of  FIG. 5 , of a hermetic seal between a loudspeaker and a main logic board in accordance with an embodiment. In an embodiment, hermetic seal  312  extends along a closed path that is not entirely curvilinear. That is, at least a portion of the path that hermetic seal  312  extends along may be a linear segment  604 , as in the case of a square path having four linear sides. A volume of acoustic cavity  314  may be defined by the rectangular area radially inward of hermetic seal  312 , multiplied by a thickness of hermetic seal  312 . Thus, the volume may be controlled by changing the profile or thickness of hermetic seal  312 . 
     Referring to  FIG. 6C , a cross-sectional view, taken about line C-C of  FIG. 5 , of a hermetic seal between a loudspeaker and a main logic board is shown in accordance with an embodiment. In an embodiment, hermetic seal  312  extends along a closed path that includes a combination of linear and curvilinear segments  602 ,  604 . For example, hermetic seal  312  may include several linear segments  604  connected at corners. Furthermore, a curvilinear segment  602  may be connected to an end of at least one of the linear segments  604 , and may traverse a distance that creates a closed path for hermetic seal  312 . The seal paths illustrated in  FIGS. 6A-6C  are provided by way of example, and a variety of different paths having linear and/or curvilinear segments  602 ,  604  may be contemplated within the scope of this description. For example, hermetic seal  312  may extend over an open path, such as a c-shaped path, and a volume within hermetic seal  312  may be acoustically coupled with another cavity located in lateral space  318  of system housing  102  through the discontinuity in the c-shape. 
     Referring to  FIG. 7 , a cross-sectional view, taken about line A-A of  FIG. 1 , of a speaker assembly of a computer system is shown in accordance with an embodiment. Computer system  101  may include speaker assembly  301  having loudspeaker  216  mounted directly on substrate  310  of main logic board  302  over a port  702 . Port  702  may be one or more holes or slots formed through substrate  310  of main logic board  302 . For example, port  702  may be drilled, etched, or otherwise incorporated in main logic board  302 . Thus, when loudspeaker  216  is connected to main logic board  302  by hermetic seal  312 , acoustic cavity  314  formed behind loudspeaker  216  may be acoustically coupled with a space below main logic board  302  through port  702 . 
     In an embodiment, the space below main logic board  302  may occupy an enclosed volume of a back casing  704 . More particularly, back casing  704  may be mounted on an underside of substrate  310  by, e.g., a hermetic bond  706 . Hermetic bond  706  may have characteristics similar to hermetic seal  312 , e.g., may be an airtight joint and include a solder and/or adhesive bond. Nonetheless, different terms are used here to refer to hermetic seal  312  and hermetic bond  706  to avoid confusion between the structures. Accordingly, a back volume of loudspeaker  216  may be enclosed between loudspeaker  216 , hermetic seal  312 , a top surface and a bottom surface of substrate  310 , hermetic bond  706 , and back casing  704 . 
     As described above, a volume may be enclosed above loudspeaker  216  by compressible seal  316  that extends between loudspeaker  216  and a bottom surface  420  of top case  304 . Thus, sound generated by loudspeaker  216  may be directed toward openings  308  into the surrounding environment without propagating into lateral space  318  within system housing  102 . In an embodiment, other system components and devices such as processor  204  or volatile memory  206  may be mounted on main logic board  302  within lateral space  318 . In an embodiment, the components are mounted on different sides of main logic board  302 , e.g., processor  204  is mounted on top of main logic board  302  and memory  206  is mounted on an underside of main logic board  302 . In other embodiments, the components may occupy space on the same side of substrate  310 . 
     Referring to  FIG. 8 , a cross-sectional view, taken about line D-D of  FIG. 7 , of a loudspeaker mounted over a main logic board and a back casing mounted below the main logic board is shown in accordance with an embodiment. In an embodiment, speaker assembly  301  includes loudspeaker  216  sandwiched between top case  304  of system housing  102  and substrate  310  of main logic board  302 , above port  702  formed through substrate  310 . Compressible seal  316  may fill a gap between top surface  418  of speaker housing  404  and top case  304 , and hermetic seal  312  may fill a gap between a bottom surface of speaker housing  404  and a top surface of substrate  310 . Thus, compressible seal  316  may be separated from hermetic seal  312  by speaker housing  404 . 
     The magnetic structure of loudspeaker  216  may be elevated relative to substrate  310 , e.g., by mounting the magnetic structure to a frame that is spaced above substrate  310 . Alternatively, the magnetic structure may be mounted directly on substrate  310 . For example, yoke  414  may contact substrate  310  and/or be connected to substrate  310  by an adhesive or solder bond, or another mechanical connector. A channel  802  may be provided through magnetic structure to allow for acoustic cavity  314  below diaphragm  402  to be acoustically coupled with port  702 . Similarly, acoustic cavity  314  may be acoustically coupled with casing cavity  804  inside back casing  704  through channel  802  and port  702 . Channel  802  may include one or more holes or slots formed through magnetic structure. For example, the holes or slots may be drilled, etched, or otherwise formed through one or more of top plate  412 , permanent magnet  410 , and yoke  414 . Thus, an acoustic passage formed in the magnetic structure may be aligned, e.g., concentrically, with an acoustic passage in main logic board  302  to interconnect acoustic cavity  314  with casing cavity  804 . Accordingly, a multi-chamber back volume may be formed in speaker assembly  301 , and in an embodiment, an outer boundary of speaker assembly  301  encompasses a front volume and a back volume defined between top case  304 , compressible seal  316 , speaker housing  404 , hermetic seal  312 , substrate  310 , hermetic bond  706 , and back casing  704 . 
     A multi-chamber back volume may include space above and below substrate  310 . For example, back volume may include the volume of acoustic cavity  314  defined between diaphragm  402 , surround  406 , speaker housing  404 , hermetic seal  312 , a top surface of substrate  310 , and/or magnetic structure. Back volume may also include the volume of casing cavity  804  defined between a bottom surface of substrate  310 , hermetic bond  706 , and/or back casing  704 . In an embodiment, back volume includes the volumes within channel  802  and port  702  extending between acoustic cavity  314  and casing cavity  804 . Thus, in an embodiment, a back volume incorporating space above and below substrate  310  utilizes more of the vertical height between top case  304  and bottom case  306  than an embodiment in which back volume resides only above or below substrate  310 . Increasing back volume may improve low frequency output, and thus, mounting loudspeaker  216  directly to main logic board  302  such that a multi-chamber back volume is integrated within airtight joints of the assembly may improve sound output and sound quality. 
     In addition to increasing speaker back volume, the chambers of speaker assembly  301  may provide shielding to other system components. As described above, main logic board  302  may incorporate components on a top side and a bottom side. For example, processor  204  may be mounted on the top side of main logic board  302  and memory may be mounted on the bottom side of main logic board  302 , or vice versa. Other components, such as passives, DRAM, etc., may be mounted on either side of main logic board  302 , and in some cases, may be mounted adjacent to loudspeaker  216 . For example, an electronic device or electronic component  806 , such as a capacitor, may be mounted on substrate  310  below loudspeaker  216 . In an embodiment, electronic component  806  may be located within casing cavity  804  such that back casing  704  shields electronic components, e.g., acoustically or electrically. 
     In an embodiment, back casing  704  acoustically shields electronic component  806  mounted on main logic board  302  within casing cavity  804  of the back volume. Back casing  704  may be formed from a material that attenuates sound waves generated by electronic component  806 . For example, back casing  704  may include a plastic shell having a thickness on the order of 1 mm. In an embodiment, a layer of acoustic foam may cover at least a portion of an inside or outside surface of back casing  704  to provide further acoustic shielding of electronic component  806 . Thus, sound generated by electronic component  806  during operation, e.g., due to vibration of the electronic component  806  during operation, may be shielded to reduce noise. Accordingly, a multi-chamber back volume can improve sound output of speaker assembly  301  and reduce noise emission from computer system  101 . In an embodiment, if system noise arises from or is contributed to by substrate vibration, the substrate that defines a portion of the multi-chamber back volume may be stiffened to further augment noise reduction. 
     In an embodiment, back casing  704  electrically shields electronic component  806  mounted to main logic board  302  within casing cavity  804  of the back volume. Back casing  704  may include a metal shell, e.g., sheet metal, metal screen, or metal foam, having a thickness on the order of 0.5 mm to 5 mm, and in some cases 1 mm. Thus, back casing  704  may provide electromagnetic shielding of electronic component  806  by reducing the electromagnetic field within casing cavity  804 . Such shielding can isolate the electronic component  806  from radiation that may negatively impact system performance. Accordingly, a multi-chamber back volume can improve sound output of speaker assembly  301  and performance of computer system  101 . 
     Referring to  FIG. 9 , a cross-sectional view, taken about line A-A of  FIG. 1 , of a speaker assembly of a computer system is shown in accordance with an embodiment. In an embodiment, speaker assembly  301  includes loudspeaker  216  mounted on a bottom surface of main logic board  302 . For example, loudspeaker  216  may be bonded to substrate  310  by hermetic seal  312  between a top surface  418  of loudspeaker  216  and a bottom surface of substrate  310 . Thus, loudspeaker  216  may be located between substrate  310  and bottom case  306 . Loudspeaker  216  may share the bottom surface of substrate  310  with other system components, such as electronic component  806 , e.g., processor  204  or memory  206 . 
     In an embodiment, loudspeaker  216  may emit sound upward toward openings  308  of top case  304  through port  702  formed in substrate  310 . More particularly, sound may be directed forward into openings  308  by compressible seal  316 , which is sandwiched between a top surface of substrate  310  and a bottom surface  420  of top case  304 . Since compressible seal  316  may be between substrate  310  and top case  304 , while hermetic seal  312  may be between substrate  310  and bottom case  306 , compressible seal  316  and hermetic seal  312  may be separated by substrate  310  of main logic board  302 . Compressible seal  316  may be acoustically rigid to create acoustic channel  416  that directs sound forward toward the surrounding environment. That is, compressible seal  316  and hermetic seal  312  may prevent sound transmission into lateral space  318  of system housing  102 . Thus, in an embodiment, port  702  interconnects acoustic channel  416 , which forms a first portion of a front volume of speaker assembly  301 , with acoustic cavity  314  above loudspeaker  216 , which forms a second portion of the front volume of speaker assembly  301 . 
     Referring to  FIG. 10 , a cross-sectional view, taken about line E-E of  FIG. 9 , of a loudspeaker mounted under a main logic board is shown in accordance with an embodiment. Speaker assembly  301  may include a multi-chamber front volume that includes acoustic channel  416  and acoustic cavity  314 . As described above, acoustic cavity  314  may include that portion of the front volume that is defined radially inward from hermetic seal  312 , which bonds speaker housing  404  to substrate  310 . More particularly, acoustic cavity  314  may be defined between diaphragm  402 , surround  406 , speaker housing  404 , hermetic seal  312 , and a bottom surface of substrate  310 . As described above, acoustic channel  416  may include that portion of the front volume that is defined radially inward from compressible seal  316 . More particularly, acoustic channel  416  may be defined between a bottom surface  420  of top case  304 , compressible seal  316 , and a top surface of substrate  310 . Front volume may also include the space within port  702 , which acoustically couples acoustic channel  416  with acoustic cavity  314 . Thus, front volume may incorporate multiple chambers that include that portion of speaker assembly  301  above diaphragm  402 , and furthermore, may include acoustic cavity  314 . Accordingly, in an embodiment, a back volume  1002  of speaker assembly  301  may be separated from acoustic cavity  314  by diaphragm  402 . 
     Back volume  1002  may include the space behind diaphragm  402  of loudspeaker  216 , within speaker housing  404 . For example, speaker housing  404  may include a fully enclosed box, enclosure, can, etc., which connects with speaker surround  406  along lip  502  to create a space within which motor assembly may be housed. In this way, back volume shape and size may be closely defined during the formation of speaker housing  404  to control the low frequency output of speaker assembly  301 . Also, since back volume  1002  may be located opposite of diaphragm  402  from substrate  310 , main logic board  302  may form a wall of the front volume of speaker assembly  301 , rather than a wall of back volume  1002 . As in several of the embodiments above, an outer boundary of speaker assembly  301  may be defined between top case  304 , compressible seal  316 , substrate  310 , hermetic seal  312 , and speaker housing  404 . 
     In the above embodiments, port  702  and/or channel  802  may be sized to limit the resistance to particle flow through a front volume and/or a back volume of speaker assembly  301 . For example, in the case of port  702  or channel  802  in any of the embodiments shown in, e.g.,  FIG. 8  or  FIG. 10 , the size of a via or passage extending through substrate  310  and/or magnetic structure may be sized such that acoustic resistance is provided to the driver to mitigate acoustic resonances. In an embodiment, the via or passage size may be at least one-tenth of the size of openings  308  that vent sound to the surrounding environment. That is, a total cross-sectional area of openings  308  may be less than ten times a total cross-sectional area of port  702  and/or channel  802 . Total cross-sectional area of any of these passages may be a cumulative cross-sectional area. For example, just as multiple openings  308  may be formed through top case  304 , a grouping of ports  702  and/or channels  802  may be provided to place different chambers of speaker assembly  301  in fluid communication through, e.g., substrate  310  (to acoustically couple the chambers). For example, manufacturability considerations may favor forming port  702  as several small through-holes, rather than as a single large through-hole. That is, five small holes may be drilled through substrate  310  to form port  702  with the same cumulative cross-sectional area as a single hole. In any case, the size and shape of the holes (including whether the holes are cylindrical, frustoconical, etc.), may be chosen to acoustically tune the holes to limit resistance to particle flow and to suppress cavity modes in speaker assembly  301 . 
     Referring to  FIG. 11 , a sectional view of a loudspeaker integrated with a main logic board is shown in accordance with an embodiment. In an embodiment, speaker assembly  301  includes loudspeaker  216  integrated directly with main logic board  302 . For example, a portion of substrate  310  of main logic board  302  may interconnect diaphragm  402  and speaker surround  406  with speaker housing  404 . Port  702  may be formed through substrate  310  such that an inner edge  1102  is created along a perimeter of port  702 . Inner edge  1102  may enclose the cross-sectional area of port  702 . Thus, by bonding speaker surround  406  to inner edge  1102 , diaphragm  402  may extend across the lateral distance between opposite sides of inner edge  1102  to cover port  702 . That is, diaphragm  402  may be movably connected with inner edge  1102  through speaker surround  406 , which flexes to allow diaphragm  402  to move pistonically relative to substrate  310 . Accordingly, sound generated by the movement of diaphragm  402  may be emitted directly into port  702  toward acoustic channel  416  and openings  308 . 
     In an embodiment in which loudspeaker  216  is integrated with main logic board  302 , compressible seal  316  is sandwiched between top case  304  and substrate  310  to form acoustic channel  416 . More particularly, compressible seal  316  may fill a gap between top case  304  and substrate  310  to limit or prevent leakage into lateral space  318  of system housing  102 . In an embodiment, compressible seal  316  includes an acoustically rigid material extending along an annular path to form acoustic channel  416  leading to openings  308  in top case  304 . Port  702  may be radially inward from compressible seal  316  such that sound passing through port  702  is delivered into acoustic channel  416  and forward through openings  308 . Alternatively, as described above, compressible seal  316  may have a side port, e.g., a break in a c-shape, such that sound entering a space within compressible seal  316  from port  702  is vented laterally between top case  304  and substrate  310  through a side-firing opening to the surrounding environment. 
     In an embodiment, speaker housing  404  is joined with a bottom side of substrate  310  by hermetic seal  312 . For example, hermetic seal  312  may bond an upper surface of speaker housing  404  with a bottom surface of substrate  310  along a closed path that is radially outward from inner edge  1102 . That is, the closed path may encompass port  702 . Accordingly, substrate  310  may separate compressible seal  316  from hermetic seal  312  in an axial direction. Furthermore, substrate  310  may separate inner edge  1102  from hermetic seal  312  in a radial direction. As such, an acoustic cavity  314  of the integrated loudspeaker may be defined between diaphragm  402 , surround  406 , a bottom surface of substrate  310 , hermetic seal  312 , speaker housing  404 , and the magnetic structure. Acoustic cavity  314  may form the entire back volume of speaker assembly  301  below diaphragm  402 , and thus, speaker housing  404  may be sized and shaped to provide a desired low frequency output. By contrast, front volume may be defined above diaphragm  402  and between diaphragm  402 , speaker surround  406 , port  702 , a top surface of substrate  310 , compressible seal  316 , and/or a bottom surface  420  of top case  304 . 
     As described above, speaker assembly  301  may include loudspeaker  216  mounted directly on substrate  310  by hermetic seal  312  to provide an acoustic cavity  314  above and/or below the substrate  310  in a space efficient and acoustically viable configuration. As a result, speaker assembly  301  may be integrated within the footprint of main logic board  302  to free up space around main logic board  302  for other system components, without degrading sound quality of computer system  101 . That is, speaker assembly  301  may have an outer boundary defined by top case  304 , compressible seal  316 , substrate  310 , hermetic seal  312 , and speaker housing  404 . It will be appreciated that the various features used to realize this configuration, e.g., an airtight seal along a closed path between a loudspeaker  216  and a main logic board  302 , a back volume and/or front volume split into multiple chambers on opposite sides of a main logic board  302 , or an acoustically rigid seal separated from the airtight seal to direct sound toward a system exit  104 , can be implemented in various other embodiments to result in a compact consumer electronics product having good sound quality. 
     In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Metadata:
Filing Date: 20141208
Publication Date: 20170516
Grant Date: 20170516
Priority Date: 20141208
Inventors: CROSBY JUSTIN D
DONARSKI MATTHEW A
BRIGHT ANDREW P
GIDDINGS JOSS N
HOPKINSON RON A
JOHANNINGSMEIER NATHAN A
LEGGETT WILLIAM F
SILVANTO MIKAEL M
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R1/2811", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/288", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/15", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/2811", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/288", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/15", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 56095521