PATENT DOCUMENT

Publication Number: US-9154883-B2
Application Number: US-201113226383-A
Country: US
Kind Code: B2

Title: Low rise speaker assembly having a dual voice coil driver

Abstract:
A speaker assembly includes an enclosure having an acoustic chamber and an acoustic output opening and a speaker driver. The speaker driver includes a sound radiating surface and a first voice coil and a second voice coil positioned along opposite faces, respectively, of the sound radiating surface. The speaker driver further includes a first magnet assembly including an elongated gap in which part of the first voice coil is positioned to vibrate and a second magnet assembly having an elongated gap in which part of the second voice coil is positioned to vibrate. The first magnet assembly elongated gap is orientated lengthwise toward the acoustic chamber, and the second magnet assembly elongated gap is oriented lengthwise toward the acoustic output opening. Other embodiments are also described and claimed.

Claims:
What is claimed is: 
     
       1. A speaker assembly comprising:
 an enclosure having an acoustic chamber and an acoustic output opening; and 
 a speaker driver having,
 a sound radiating surface, 
 a first voice coil and a second voice coil positioned along opposite faces, respectively, of the sound radiating surface, 
 a first magnet assembly having an elongated gap in which part of the first voice coil is positioned to vibrate, and 
 a second magnet assembly having an elongated gap in which part of the second voice coil is positioned to vibrate, 
 
 wherein the first magnet assembly elongated gap is orientated lengthwise toward the acoustic chamber, and the second magnet assembly elongated gap is oriented lengthwise toward the acoustic output opening. 
 
     
     
       2. The speaker assembly of  claim 1  wherein an angle formed between the lengthwise dimension of the first magnet assembly elongated gap and the lengthwise dimension of the second magnet assembly elongated gap is between 0 degrees and 180 degrees. 
     
     
       3. The speaker assembly of  claim 1  wherein the first magnetic assembly elongated gap directs air flow in a first direction and the second magnetic assembly elongated gap directs air flow in a second direction different from the first direction. 
     
     
       4. The speaker assembly of  claim 3  wherein the first direction is substantially perpendicular to the second direction. 
     
     
       5. The speaker assembly of  claim 1  wherein the first voice coil and the second voice coil move in parallel to drive movement of the sound radiating surface. 
     
     
       6. The speaker assembly of  claim 1  wherein the elongated gap of the first magnet assembly is a first elongated gap and the first magnet assembly defines a second elongated gap parallel to the first elongated gap. 
     
     
       7. The speaker assembly of  claim 1  wherein the elongated gap of the second magnet assembly is a first elongated gap and the second magnet assembly defines a second elongated gap parallel to the first elongated gap. 
     
     
       8. The speaker assembly of  claim 1  wherein a z height of the speaker driver is oriented in substantially the same direction as a z height of the enclosure. 
     
     
       9. A speaker comprising:
 a frame; 
 a sound radiating surface; 
 a first voice coil and a second voice coil positioned along opposite faces, respectively, of the sound radiating surface; 
 a first magnet assembly defining an elongated gap in which part of the first voice coil is positioned to vibrate; and 
 a second magnet assembly defining an elongated gap in which part of the second voice coil is positioned to vibrate, 
 wherein a length dimension of the first magnet assembly elongated gap is oriented in a different direction than a length dimension of the second magnet assembly elongated gap. 
 
     
     
       10. The speaker of  claim 9  wherein an angle formed by the length dimension of the first magnet assembly elongated gap and the length dimension of the second magnetic assembly elongated gap is between 0 degrees and 180 degrees. 
     
     
       11. The speaker of  claim 9  wherein the first magnetic assembly elongated gap directs air in a first direction and the second magnetic assembly elongated gap directs air in a second direction. 
     
     
       12. The speaker of  claim 11  wherein the first direction is substantially perpendicular to the second direction. 
     
     
       13. The speaker of  claim 9  wherein the first voice coil and the second voice coil move in parallel to drive movement of the sound radiating surface. 
     
     
       14. A portable audio device comprising:
 an enclosure having a front face, a back face, at least one side wall connecting the front face to the back face, an acoustic chamber formed between the front face and the back face and an acoustic output opening formed within the at least one side wall; 
 a diaphragm positioned within the enclosure; 
 a first voice coil and a second voice coil positioned along opposite faces, respectively, of the diaphragm; 
 a first magnet assembly in which part of the first voice coil is positioned to vibrate; and 
 a second magnetic assembly in which part of the second voice coil is positioned to vibrate, 
 wherein the first magnet assembly is dimensioned to direct air flow to the acoustic chamber and the second magnetic assembly is dimensioned to direct air flow toward the acoustic output opening. 
 
     
     
       15. The portable audio device of  claim 14  wherein the first magnet assembly defines at least one elongated gap dimensioned to receive the first voice coil and direct air flow to the acoustic chamber and the second magnet assembly defines at least one elongated gap dimensioned to receive the second voice coil and direct air flow to the acoustic output opening. 
     
     
       16. The portable audio device of  claim 15  wherein an angle formed between a lengthwise dimension of the first magnet assembly elongated gap and a lengthwise dimension of the second magnet assembly elongated gap is between 0 degrees and 180 degrees. 
     
     
       17. The portable audio device of  claim 15  wherein the first magnetic assembly elongated gap directs air flow in a first direction and the second magnetic assembly elongated gap directs air flow in a second direction different from the first direction. 
     
     
       18. The portable audio device of  claim 17  wherein the first direction is substantially perpendicular to the second direction.

Description:
BACKGROUND 
     In modern consumer electronics, audio capability is playing an increasingly larger role as improvements in digital audio signal processing and audio content delivery continue to happen. There is a range of consumer electronics devices that are not dedicated or specialized audio playback devices, yet can benefit from improved audio performance. For instance, smart phones are ubiquitous. These devices, however, do not have sufficient space to house high fidelity speakers. This is also true for portable personal computers such as laptop, notebook, and tablet computers, and, to a lesser extent, desktop personal computers with built-in speakers. Such devices typically require speaker enclosures or boxes that have a relatively low rise (i.e. height as defined along the z-axis) and small back volume, as compared to, for instance, stand alone high fidelity speakers and dedicated digital music systems for handheld media players. 
     In low rise speaker boxes, there is an advantage to using speakers that maintain a high “Bl” product in order to reduce low frequency displacement (this prevents high total harmonic distortion (THD), rub and buzz) and to increase the sensitivity. In conventional speakers, the magnet unit thickness is typically reduced as the box thickness is reduced to allow for airflow around the transducer. The reduced z height of the magnet system means that the force generated by the coil is smaller (when an audio signal is being applied to the speaker). Therefore, any gains in THD, rub, buzz and sensitivity are lost due to the lower force that is generated by the coil and magnet system. Previous efforts to address this problem have focused on including additional voice coil and magnet systems forming a push pull system within the enclosure to increase the “Bl” product and hence the sound output. Such systems, however, often require a significant increase in the height of the enclosure in order to maintain sufficient air flow through the system. 
     SUMMARY 
     An embodiment of the invention is a speaker assembly having an enclosure with an acoustic output opening, an acoustic chamber, and a speaker driver. The speaker driver includes a sound radiating surface, first and second voice coils positioned along opposite faces, respectively, of the sound radiating surface, and first and second magnet assemblies having elongated gaps within which portions of the first and second voice coils are positioned to vibrate. The first magnet assembly elongated gap can be orientated lengthwise toward the acoustic output opening, while the second magnet assembly elongated gap is oriented lengthwise toward the acoustic chamber. The elongated gaps may be used as air flow paths to direct a flow of air toward the acoustic output opening and toward the acoustic chamber so that a height or rise of the enclosure need not be significantly increased to accommodate the stacked voice coil and magnet assembly configuration. 
     In one embodiment, an angle formed between the lengthwise dimension of the first magnet assembly elongated gap and the lengthwise dimension of the second magnet assembly elongated gap is between 0 degrees and 180 degrees. For example, the angle may be about 90 degrees. This defines a position of the acoustic output opening formed by the enclosure, relative to the acoustic chamber, and allows air flow (produced by the moving sound radiating surface) to be directed in at least two different directions. These directions may be defined by the desired orientation of the acoustic chamber relative to the acoustic output opening. 
     The above summary does not include an exhaustive list of all aspects of the embodiments disclosed herein. It is contemplated that the embodiments may include 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 
       The embodiments disclosed herein are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and they mean at least one. 
         FIG. 1  is a perspective view of a speaker having a dual voice coil driver. 
         FIG. 2A  is a side view of the embodiment of  FIG. 1 . 
         FIG. 2B  is a side view of the embodiment of  FIG. 1 . 
         FIG. 3  is a top exploded view of the embodiment of  FIG. 1 . 
         FIG. 4  is a top perspective cut out view of a speaker enclosure having the speaker of  FIG. 1  positioned therein. 
         FIG. 5  is a top exploded view of another embodiment of a speaker having a dual voice coil driver. 
         FIG. 6  depicts two instances of consumer electronics devices that typically specify low rise speakers in which the speakers disclosed herein may be implemented. 
     
    
    
     DETAILED DESCRIPTION 
     In this section we shall explain several preferred embodiments with reference to the appended drawings. Whenever the shapes, relative positions and other aspects of the parts described in the embodiments are not clearly defined, the scope of the embodiments is not limited only to the parts shown, which are meant merely for the purpose of illustration. Also, while numerous details are set forth, it is understood that some embodiments may be practiced without these details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the understanding of this description. 
       FIG. 1  is a perspective view of a speaker having a dual voice coil driver. Speaker  100  is built into frame  102  which may be of a typical material used for speaker enclosures, such as plastic. Frame  102  may be part of a speaker enclosure or box  101  whose height (or rise) and speaker back volume  140  (also referred to as an acoustic chamber) are considered to be relatively small. For example, the enclosure height or rise may be in the range of about 8.5 millimeters (mm) to about 10 mm and the speaker back volume or acoustic chamber may be in the range of about 0.25 cubic centimeters (cm) to 2 cubic cm. The concepts described here, however, need not be limited to speaker enclosures whose rise and back volume are within these ranges. As seen in  FIG. 6 , such a speaker may be a speakerphone unit that is integrated within a consumer electronic device  602  such as a smart phone with which a user can conduct a call with a far-end user of a communications device  604  over a wireless communications network; in another example, the speaker may be integrated within the housing of a tablet computer. These are just two examples of where the speaker may be used. 
     Speaker  100  may include a dual voice coil driver having first magnet assembly  104  and second magnet assembly  106 .  FIG. 1  illustrates an embodiment where first magnet assembly  104  and second magnet assembly  106  are positioned along opposite faces of sound radiating surface (SRS)  136 . Each of first magnet assembly  104  and second magnet assembly  106  may define gaps within which a portion of coils  116 ,  118  (also referred to as voice coils), respectively, may be positioned to produce a push pull speaker system. In other words, one of coils  116 ,  118  acts to “push” sound radiating surface  136  while the other coil simultaneously “pulls” sound radiating surface  136  in the same direction. Sound radiating surface  136  is therefore moved more forcefully which in turn increases “Bl” product and sound output from the device. 
     Although positioning first magnet assembly  104  and second magnet assembly  106  along opposite faces of sound radiating surface  136  provides several advantages, such a configuration also reduces the space between the face of sound radiating surface  136  and the enclosure. This space is typically reserved for air flow between sound radiating surface  136  and both the back volume of the enclosure and the acoustic output opening. Air flow through speaker  100  is important in order to transmit sound to the user. In addition, air flow helps cool the coils, thereby allowing the speaker to perform well at higher power levels and longer operation intervals. 
     To maintain space for air flow without substantially increasing a height (or rise) of the enclosure, the gaps  108 ,  110  formed within first magnet assembly  104  and the gaps  112 ,  114  formed within second magnet assembly  106  are used as air flow paths. In particular, first magnet assembly  104  may include center magnet piece  120  positioned between outer magnet piece  122  and outer magnet piece  124 . First gap  108  may be formed between outer magnet piece  122  and one side of center magnet piece  120  as shown. Second gap  110  may be formed between the other side of center magnet piece  120  and outer magnet piece  124 . In an embodiment where outer magnet pieces  122 ,  124  and center magnet piece  120  have square or rectangular shapes as shown in  FIG. 1 , gap  108  may run parallel to second gap  110 . It is contemplated, however, that outer magnet pieces  122 ,  124  and center magnet piece  120  may have other shapes. For example, center magnet piece  120  may have a circular or elliptical shape and outer magnet pieces  122 ,  124  may be arc shaped pieces that have a curve similar to that of a portion of an outer circumference of center magnet piece  120 . In such an embodiment, the first and second gaps defined by the magnet pieces may be curved toward one another. 
     Similar to first magnet assembly  104 , second magnet assembly  106  may include first gap  112  formed between one side of center magnet piece  126  and outer magnet piece  128  and second gap  114  may be formed between the other side of center magnet piece  126  and outer magnet piece  130 . First gap  112  may run parallel to second gap  114 , or in the case of a circular or elliptical center magnet piece, the gaps may be curved toward one another as previously discussed. First magnet assembly  104  and second magnet assembly  106  may be fixed to frame  102 . It is further contemplated that speaker  100  may include other magnet assemblies that can provide a sufficiently strong magnetic flux (within a suitably shaped air gap for the coil). 
     Gaps  108 ,  110  and gaps  112 ,  114  may be oriented with respect to one another so that they can direct air flow, and in turn sound waves, in one or more desired directions. For example, first magnet assembly  104  may be positioned such that its gaps  108 ,  110  are oriented lengthwise in a direction of an acoustic output opening of enclosure  101  while second magnet assembly  106  may be positioned so that its gaps  112 , 114  are oriented lengthwise in a direction of back volume or acoustic chamber  140  of enclosure  101 . Alternatively, gaps  108 ,  110  may direct air to the acoustic chamber and gaps  112 ,  114  may direct air to the acoustic output opening. 
     Air flow through gaps  112 ,  114  directs sound waves generated by the top face of SRS  136  into chamber  140  while air flow through gaps  108 ,  110  directs sound waves generated by the bottom face of SRS  136  out of enclosure  101 . It is noted that the sound waves generated by opposing faces of SRS  136  are out of phase with one another. It is therefore important to prevent the sound waves generated by the top face of SRS  136  from interacting with sound waves generated by the bottom face of SRS  136 . To prevent such interactions, acoustic chamber  140  may be sealed off from the area below the bottom face of SRS  136  by wall  142 . Wall  142  may be a substantially rigid structure that is attached to SRS  136  by, for example, gluing one side of suspension  138  to the upper edge of wall  142  and the other side of suspension  138  to SRS  136 . Wall  142  may be part of frame  102  or it may be a part of enclosure  101 . 
       FIG. 4  illustrates an embodiment where speaker  402 , which is substantially the same as speaker  100 , directs air flow out of enclosure  404  in a direction of acoustic output opening  406  as illustrated by arrows  302 ,  304  and back volume  410  as illustrated by arrows  306 ,  308 . As shown in  FIG. 4 , enclosure  404  includes front face  412  and back face  414  which are joined together by opposing side walls  416 ,  418 , bottom wall  420  and top wall  422 . Acoustic output opening  406  is formed within side wall  418 . It is contemplated, however, that acoustic output opening  406  may be formed within side wall  416 , bottom wall  420  or top wall  422 . Back volume  410  is formed between top wall  422 , bottom wall  414  and portions of side walls  416 ,  418 . To direct the air flow toward back volume  410  and out acoustic output opening  406  formed in side wall  418  without substantially increasing a rise or height of enclosure  404 , speaker  402  is positioned within enclosure  404  so that elongated gaps  108 ,  110 ,  112  and  114  are oriented lengthwise within a plane defined by an x-y axis and a height or z height (as defined along the z-axis) of speaker  402  is in the same direction as a z height (also defined along the z-axis) of enclosure  404 . In this aspect, air flow out of speaker  100  may be maintained without substantially increasing a rise or height of the enclosure. 
     Returning to  FIG. 1 , coil  116 , which is affixed to the former  132 , may be positioned around center magnet piece  120  (as shown in  FIG. 3 ) and coil  118 , which is affixed to former  134 , may be positioned around center magnet piece  126 . It is noted that although formers  132 ,  134  are illustrated, formers  132 ,  134  are optional and may be omitted in some embodiments. Coils  116 ,  118  may be pre-wound coil assemblies (which include the wire coil held in its intended position by a lacquer or other adhesive material), which may be bonded directly to their respective formers, for example to the outer surface wall of the formers. In other embodiments, formers may be omitted and coils  116 ,  118  may be attached directly to opposite faces of SRS  136 . Other ways of attaching or forming coils  116 ,  118  in such a fixed position (relative to formers  132 ,  134 ) are possible. 
     Although not shown, coils  116 ,  118  have electrical connections to a pair of terminals through which an input audio signal is received, in response to which coils  116 ,  118  produce a changing magnetic field that interacts with the magnetic field produced by magnet assemblies  104 ,  106 , respectively, for providing a driving mechanism for speaker  100 . Coils  116 ,  118  may be pre-wound wire coil units that have been shaped to fit within gaps  108 ,  110  and gaps  112 ,  114  of first magnet assembly  104  and second magnet assembly  106 , respectively. In this example, coils  116 ,  118  (and corresponding formers  132 ,  134 ) have a substantially square or rectangular shape. 
     During operation, coils  116 ,  118  move in parallel to drive movement of sound radiating surface  136 . Parallel movement of coils  116 ,  118  may be controlled by the polar orientation of coils  116 ,  118  and/or the magnet orientation of first magnet assembly  104  and second magnet assembly  106 . For example, magnet pieces  120 ,  122  and  124  of first magnet assembly  104  and magnet pieces  126 ,  128  and  130  of second magnet assembly  106  may be oriented so that a direction of the magnetic field generated by first magnet assembly  104  is opposite the direction of the magnetic field generated by second magnet assembly  106 . The opposing magnetic fields interact with the magnetic field produced by coils  116 ,  118  when current is passed through coils  116 ,  118 , causing them to move in parallel, i.e., in a push-pull fashion. Alternatively, the polar orientation of coils  116 ,  118  may be modified to drive parallel movement of coils  116 ,  118 . 
     Sound radiating surface  136  may be coupled to frame  102  by way of suspension  138  as shown in  FIGS. 2A and 2B . Sound radiating surface  136  may be a flat plate, or it may be a dome; the latter is likely to weigh less but may provide less high frequency performance (for the same area size). Suspension  138  allows substantially vertical movement of sound radiating surface  136 , that is in a substantially up and down direction or also referred to as a forward-backward direction, relative to fixed frame  102 . Suspension  138  may be any flexible material such as foam or rubber or membrane made of a thermoformed plastic that is sufficiently flexible to allow movement of the sound radiating surface in order to produce acoustic or sound waves. The sound radiating surface  136  may be more rigid or less flexible, to be more efficient in producing high frequency acoustic waves. In one instance, suspension  138  is an outer portion of a single-piece flexible membrane, and sound radiating surface  136  includes a rigid plate or dome that may be attached to an inner portion of the flexible membrane. This may be done by directly gluing the sound radiating surface to the top face of the flexible membrane; alternatively, the sound radiating surface may be bonded directly to a top portion of former  132  and a bottom portion of former  134 , next to where the flexible membrane is bonded. Suspension  138  may also be viewed as an annular surround that is attached to sound radiating surface  136 , along a peripheral portion of the latter. Suspension  138  may also serve to maintain sound radiating surface  136  in substantial alignment relative to a center vertical axis of formers  132 ,  134  during operation of the speaker. This alignment also serves to prevent a moving coil from getting snagged by the walls of the magnet system. 
     Former  132  and former  134  may have a typical, generally cylindrical or ring like structure around which a voice coil can be wound. Alternatively, formers  132 ,  134  may be flat plates with a central opening therein which extends substantially horizontally outward of a peripheral portion of sound radiating surface  136 , to a peripheral portion that is separate from suspension  138 . In this aspect, sound radiating surface  136  may be attached to a top face of the annular portion of the horizontal former. Formers  132 ,  134  may be made from any suitably lightweight yet rigid material, so as to keep the weight of the suspended combination with sound radiating surface  136  to a minimum, for greater performance and efficiency. An example material is an aluminum alloy. Other suitable materials include titanium and ceramic, both of which may be made sufficiently lightweight yet rigid. 
       FIG. 2A  and  FIG. 2B  are side views of the speaker having the dual voice coil driver of  FIG. 1 .  FIG. 2A  shows a side of speaker  100  facing a side wall of the enclosure.  FIG. 2B  shows a side of speaker  100  facing a front or back wall of the enclosure. These views illustrate the alignment and positioning of first magnet assembly  104  and second magnet assembly  106  along opposite faces of sound radiating surface  136 . First magnet assembly  104  is positioned along a bottom face of sound radiating surface  136  and second magnet assembly  106  is positioned along a top face of sound radiating surface  136 . It is contemplated, however, that first magnet assembly  104  and second magnet assembly  106  may be positioned along different faces of sound radiating surface  136 . First magnet assembly is oriented such that its first gap  108  and second gap  110  extend lengthwise into the page. Second magnet assembly  106  is oriented such that the length dimension of its first gap  112  and second gap  114  form about a 90 degree angle with the first gap  108  and second gap  110 . This orientation is illustrated in the spread apart view of  FIG. 3 , where it should be understood that the magnet assemblies  104 ,  106  are actually stacked. In particular, first magnet assembly  104  includes first gap  108  and second gap  110  oriented in a lengthwise direction perpendicular to first gap  112  and second gap  114  of second magnet assembly  106 . Such orientation directs air flow (caused by up and down vibration of SRS  136 ) in two different directions perpendicular to one another. Representatively, air flows through first gap  108  and second gap  110  of first magnet assembly  104  in a first direction illustrated by arrows  302 ,  304 , respectively, while air flows through first gap  112  and second gap  114  of second magnet assembly  106  in a second direction illustrated by arrows  306 ,  308 , respectively. According to this example, gaps  108 ,  110 , and in turn, air flow in the first direction (along arrows  302 ,  304 ) is perpendicular, or at a 90 degree angle (α), to gaps  112 ,  114 , and in turn, air flow in the second direction (along arrows  306 ,  308 ). By directing air flow in this manner, a sufficient volume of air flow can be directed between the back volume (see  410  of  FIG. 4 ) and the acoustic output opening (see  406  of  FIG. 4 ) of the enclosure (see  404  of  FIG. 4 ). 
     Although arrows  302 ,  304  and arrows  306 ,  308  illustrate air flow through gaps  108 ,  110  and gaps  112 ,  114 , respectively, in a single direction, it should be understood that each of gaps  108 ,  110  and gaps  112 ,  114  may accommodate bidirectional air flow. As illustrated in  FIG. 1 , enclosure  101  includes vertically extending side walls that are positioned around first magnet assembly  104  and second magnet assembly  106 . Portions of the walls positioned at the end of gaps  108 ,  110  and/or gaps  112 ,  114  impede air flow out of gaps  108 ,  110  and/or gaps  112 ,  114  in the direction of the wall. Instead, air will travel out the end of gaps  108 ,  110  and/or gaps  112 ,  114  directed toward the back volume or the acoustic output opening. Where additional openings are included in the enclosure, for example acoustic output openings and/or air vents along both ends of gaps  108 ,  110  and/or gaps  112 ,  114 , air flow may be bidirectional and out both ends of the gaps. 
     The magnet assembly orientation illustrated in  FIG. 3  is desirable where acoustic output opening  406  is positioned along a side of enclosure  404  as illustrated in  FIG. 4 . In embodiments where the acoustic output opening is positioned along a different portion of enclosure  404 , for example, along back volume  410 , first magnet assembly  104  and second magnet assembly  106  may be oriented as illustrated in  FIG. 5 . In this embodiment, first air gap  112  and second air gap  114  of second magnet assembly  106  are oriented in a lengthwise direction toward an upper right hand corner of the enclosure (e.g. enclosure  404 ) and first gap  108  and second gap  110  of first magnet assembly  104  are oriented in a lengthwise direction toward the back volume. As such, an angle formed by first magnet assembly elongated gaps  108 ,  110 , and in turn, air flow in the first direction (along arrows  502 ,  504 ) and second magnet assembly elongated gaps  112 ,  114 , and in turn, air flow in the second direction (along arrows  506 ,  508 ) is greater than 90 degrees, for example at an angle of about 135 degrees (θ). In this aspect, air flow is directed by first magnet assembly  104  along air flow paths  502 ,  504  toward a back volume and by second magnet assembly  106  along air flow paths  506 ,  508  toward a side of the enclosure defining the back volume. 
     Although two different magnet assembly orientations are illustrated in  FIG. 3  and  FIG. 5 , it is contemplated that first magnet assembly  104  and second magnet assembly  106  may be oriented in any manner desired so that their respective gaps direct an air flow to a desired portion of the enclosure. Representatively, an angle formed by elongated gaps  108 ,  110  of first magnet assembly  104  and gaps  112 ,  114  of second magnet assembly  106  may be between 0 degrees and 180 degrees, for example, from about 45 degrees to about 135 degrees, or about 90 degrees. Alternatively, gaps  108 ,  110  and gaps  112 ,  114  may be aligned in parallel such that they form a 0 or 180 degree angle with respect to one another. 
     A process of manufacturing the speaker described above, and in particular the assembly that includes first magnet assembly  104  attached to coil  116  and former  132 , second magnet assembly  106  attached to coil  118  and former  134 , suspension  138  and sound radiating surface  136  may proceed as follows. Coils  116 ,  118  may be obtained as pre-wound units, which are then secured to formers  132 ,  134 , respectively, along the outer elongated walls. Next, sound radiating surface  136 , which may be a rigid plate or dome is attached to a top end of former  132  and a bottom end of former  134 . At the same time, or just before or just after, an inner region of the suspension  138  is attached to the top end of former  132  and the bottom end of former  134 . Formers  132 ,  134  having coils  116 ,  118  positioned thereon, are then positioned within gaps of first magnet assembly  104  and second magnet assembly  106 , respectively. Alternatively, in embodiments where formers  132 ,  134  are omitted, coils  116 ,  118  and suspension  138  may be attached directly to sound radiating surface  136 . 
     In the above manufacturing process, formers  132 ,  134  may have been manufactured as separate pieces than sound radiating surface  136 . However, as an alternative, formers  132 ,  134  and sound radiating surface  136  may be manufactured as a single piece. Such a former-radiating surface element could be milled, cut or stamped from a solid sheet of material such as aluminum alloy (or other suitably lightweight yet rigid material). The manufacturing process would otherwise remain the same. 
     While certain embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive, and that the embodiments disclosed herein are not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those of ordinary skill in the art. For example, although the drawings show the gap in the magnet system, the coil, and the horizontal former all having essentially the same rectangular or square shape, an alternative may be a substantially elliptical or oval shape or even round in shape. The description is thus to be regarded as illustrative instead of limiting.

Metadata:
Filing Date: 20110906
Publication Date: 20151006
Grant Date: 20151006
Priority Date: 20110906
Inventors: WILK CHRISTOPHER
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R9/025", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R2209/041", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/046", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2209/022", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/046", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2209/041", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R2209/022", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 46940581