Abstract:
A new audio transducer for mobile devices, in particular for a micro speaker, having a coil assembly having a coil, a pair of leads extending from the coil, and a flexible printed circuit having a pair of contact pads to which the leads are directly electrically connected. An advantage of this new speaker is the reduced number of electrical connections between the leads of the coil and the driver of the coil. This helps to reduce the number and size of the parts of the micro speaker and aids in increasing sound quality and durability of the speaker.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    a. Field of the Invention 
         [0002]    The invention relates to an audio transducer, such as a speaker to transduce an electrical audio signal into acoustic sound or a receiver to transduce an acoustic sound into an electrical audio signal. This invention furthermore relates to a micro speaker optimized for high acoustic output and located within a small volume of a mobile device, such as a mobile phone, a tablet, a gaming device, a notebook or similar device. 
         [0003]    b. Background Art 
         [0004]    Prior art micro speakers for use in mobile devices include a coil fixed to the membrane of the speaker. The coil includes two leads to feed an electrical signal into the coil. The coil is arranged within a magnetic field formed of a population of magnets. The electrical signal fed into the coil causes the coil and connected membrane to vibrate which generates an acoustic sound in relation to the electrical signal. Prior art micro speakers include a frame to align and fix the parts of the speaker. The frame includes contact pads which provide the electrical interface between the coil and the audio electronics of the mobile device. 
       SUMMARY OF THE INVENTION 
       [0005]    It is an object of the invention to have an audio transducer for mobile devices without the disadvantages of known transducers. A new audio transducer for mobile devices, in particular for a micro speaker, comprises a coil assembly having a coil, a pair of leads extending from the coil, and a flexible printed circuit having a pair of contact pads to which the leads are directly electrically connected. An advantage of this new speaker is the reduced number of electrical connections between the leads of the coil and the driver of the coil. This helps to reduce the number and size of the parts of the micro speaker and aids in increasing sound quality and durability of the speaker. Further details and advantages of such an audio transducer will become apparent in the following description and the accompanying drawings. 
         [0006]    Briefly therefore, one aspect of the invention is directed to an audio transducer, comprising a substantially rectangular pot plate having a perimeter, a substantially rectangular collar, a membrane, a magnet system, and coil assembly. The substantially rectangular collar includes a first portion substantially parallel to the pot plate, a substantially rectangular hole extending through the first portion of the collar. A second portion of the collar extends substantially perpendicular downward from the first portion, and a support tab extends substantially perpendicular outward from the second portion. The membrane includes a perimeter affixed to the first portion of the collar. The magnet system includes a perimeter magnet assembly, a center magnet assembly, and an air gap formed between the perimeter magnet assembly and the center magnet assembly. The perimeter assembly comprises a population of outer magnets arranged proximate the perimeter of the pot plate and a ring plate affixed to the population of outer magnets. The center magnet assembly comprises a center magnet affixed to the pot plate and substantially surrounded by the population of outer magnets of the perimeter magnet system, and a top plate affixed to the center magnet. The coil assembly includes a coil located in the air gap, wherein the coil has a top side affixed to the membrane. A pair of electrical leads extend from the coil and are directly electrically connected to a pair of contact pads on a flexible printed circuit. The support tab of the collar is affixed to the flexible printed circuit. 
         [0007]    While embodiments of the audio transducer are shown and described as having a rectangular shape, it will be understood that in other embodiments, the audio transducer may have a variety of shapes, including, but not limited to, circular and ovular. Accordingly, the invention is not limited to audio transducers having a rectangular shape. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    These and other aspects, features, details, utilities, and advantages of the invention will become more fully apparent from the following detailed description, appended claims, and accompanying drawings, wherein the drawings illustrate features in accordance with exemplary embodiments of the invention, and wherein: 
           [0009]      FIG. 1  shows an exploded top perspective view of the relevant parts of a prior art rectangular micro speaker; 
           [0010]      FIG. 2A  shows a bottom perspective view of the relevant parts of a prior art rectangular micro speaker; 
           [0011]      FIG. 2B  shows a bottom perspective view of the relevant parts of a prior art rectangular micro speaker; 
           [0012]      FIG. 3  shows an exploded top perspective view of a rectangular micro speaker according to a first embodiment of the invention; 
           [0013]      FIG. 4  shows a top perspective view of a coil assembly of a rectangular micro speaker according to the first embodiment of the invention; 
           [0014]      FIG. 5  shows a top perspective view of a rectangular micro speaker according to the first embodiment of the invention; 
           [0015]      FIG. 6  is a flowchart describing a method of manufacturing the rectangular micro speaker according to the first embodiment of the invention; 
           [0016]      FIG. 7  is a top perspective view of a rectangular micro speaker within an enclosure according to the first embodiment of the invention; 
           [0017]      FIG. 8A  is a top perspective view of a collar of a rectangular micro speaker according to a second embodiment of the invention; 
           [0018]      FIG. 8B  is a bottom perspective view of a rectangular micro speaker according to a second embodiment of the invention; 
           [0019]      FIG. 9A  is a bottom perspective view of a collar of a rectangular micro speaker according to the third embodiment of the invention; 
           [0020]      FIG. 9B  is a top perspective view of a collar of a rectangular micro speaker according to the third embodiment of the invention. 
       
    
    
       [0021]    Like reference numbers refer to like or equivalent parts in the several views. 
       DETAILED DESCRIPTION OF EMBODIMENTS 
       [0022]    Various embodiments are described herein to various apparatuses. Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. It will be understood by those skilled in the art, however, that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Those of ordinary skill in the art will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments, the scope of which is defined solely by the appended claims. 
         [0023]    Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment,” or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment,” or the like, in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features, structures, or characteristics of one or more other embodiments without limitation given that such combination is not illogical or non-functional. 
         [0024]    It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the content clearly dictates otherwise. 
         [0025]    The terms “first,” “second,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms “include,” “have,” and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. 
         [0026]    The terms “left,” “right,” “front,” “rear,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. 
         [0027]    All numbers expressing measurements and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” 
         [0028]      FIG. 1  shows an exploded perspective view of the relevant parts of a prior art rectangular micro speaker  10 . Speaker  10  comprises a membrane  12  that is typically built out of one or more layers of material, such as, for example, Ethere Ketone (PEEK), Acrylate and/or Thermoplastic Elastomeric (TEP), Polyetherimide (PEI), and/or other materials known in the art. Membrane  12  may also include a membrane plate  14  to stiffen membrane  12 . Speaker  10  furthermore comprises a coil  32  with leads  34 . An electrical signal to drive coil  32  is fed into coil  32  through leads  34 . Coil  32  of assembled speaker  10  is fixed to membrane  12  with an adhesive, such as, for example, glue, tape, or other adhesives known in the art. 
         [0029]    Speaker  10  includes a magnet system  50  comprising a perimeter magnet assembly  52  and a center magnet assembly  60 . Perimeter magnet assembly  52  includes four magnets  54  arranged on the rectangular sides of the rectangular speaker  10  and ring plate  58  fixed to magnets  54 . Center magnet assembly  60  includes magnet  62  arranged in the center of speaker  10  and top plate  64  fixed to magnet  62 . Perimeter magnet assembly  52 , center magnet assembly  60 , and pot plate  80  affixed to perimeter and center magnet assemblies  52 ,  60  opposite ring and top plates  58 ,  64  form magnetic field guide  68 . Magnetic field guide  68  guides and focuses the magnetic field of magnets  54  and  62  in an air gap  70  between perimeter magnet assembly  52  and center magnet assembly  60 , into which coil  32  is arranged in the assembled speaker  10 . 
         [0030]    Prior art micro speaker  10  further includes frame  90  to assemble and align membrane  12  with magnet system  50 . Coil  32  fits into air gap  70  and is able to translate up and down within air gap  70  according to the electrical signal fed into coil  32  through leads  34 . Frame  90  typically is made from a molded plastic which enables frame  90  to have a complex surface with openings which permit airflow and fixation of other parts of speaker  10 . The ends of leads  34  of coil  32  are soldered to contact pads  92   t,  that are fixed in to top side of frame  90  during an assembly process. As shown in  FIG. 2A , the bottom side of frame  90  includes contact pads  92   b  which are electrically connected with contact pads  92   t  on the top side of frame  90 . As shown in  FIG. 2B , a further electrical connection is made with flexible printed circuit  94  which includes contact pads  96 . Contact pads  96  of flexible printed circuit  94  are soldered to contact pads  92   b  during an assembly process. The electrical signal to drive coil  32  is fed through flexible printed circuit  94 , contact pads  96 , contact pads  92   b,  contact pads  92   t,  and into leads  34 . Furthermore as shown in  FIGS. 2A and 2B , pot plate  80  includes bottom vents  98  which permit airflow between a back volume (not shown) and the back volume side of the membrane  12 . Bottom vents  98  permit an undistorted vibration of membrane  12  according to the electrical signal fed into coil  32 . 
         [0031]    The relevant parts of a first embodiment of the invention is shown in  FIGS. 3, 4, 5, 6, and 7 .  FIG. 3  shows an exploded perspective view of the relevant parts of a rectangular speaker  110 .  FIG. 4  shows a perspective view of an assembly of a coil  132  and flexible printed circuit  136 .  FIG. 5  shows a top perspective view the relevant parts of the assembled speaker  110 .  FIG. 6  is a flowchart describing a method of manufacturing speaker  110 .  FIG. 7  is a top perspective view of the assembled speaker  110  within an enclosure  190 . 
         [0032]    Speaker  110  comprises a membrane  112 , a collar  116 , a coil assembly  130 , a magnet system  150 , and a pot plate  180 . Membrane  112  may be built out of one or more layers of material, such as, for example, Ethere Ketone (PEEK), Acrylate and/or Thermoplastic Elastomeric (TEP), Polyetherimide (PEI), and/or other materials known in the art. Membrane  112  may also include a membrane plate  114  to stiffen membrane  112 . 
         [0033]    Speaker  110  includes a magnet system  150  comprising a perimeter magnet assembly  152  and a center magnet assembly  160 . Perimeter magnet assembly  152  includes four magnets  154  arranged on the rectangular sides of the rectangular speaker  110  and ring plate  158  fixed to magnets  154 . Center magnet assembly  160  includes magnet  162  arranged in the center of speaker  110  and top plate  164  fixed to magnet  162 . Perimeter magnet assembly  152 , center magnet assembly  160 , and pot plate  180  affixed to perimeter and center magnet assemblies  152 ,  160  opposite ring and top plates  158 ,  164  form magnetic field guide  168 . Magnetic field guide  168  guides and focuses the magnetic field of magnets  154  and  162  in an air gap  170  between perimeter magnet assembly  152  and center magnet assembly  160 , into which coil  132  is arranged in the assembled speaker  110 . 
         [0034]    Speaker  110  includes coil assembly  130  having coil  132 , leads  134 , and flexible printed circuit  136 . An electrical signal to drive coil  132  is fed into coil  132  through flexible printed circuit  136  and leads  134 . Coil  132  of assembled speaker  110  is fixed to membrane  112  with an adhesive, such as, for example, glue, tape, or other adhesives known in the art. Unlike prior art micro speakers, leads  134  of coil  132  are directly connected to flexible printed circuit  136 . Flexible printed circuit  136  includes a pair of contact pads  138  on a first terminal end of flexible printed circuit  136  which are in electrical communication with contact pads  140  on a second terminal end of the printed circuit  136  opposite the first. The electrical communication between contact pads  140  and  138  may be accomplished using traces and/or vias as is known in the art. Leads  134  are electrically connected by a solder connection to contact pads  138  to permit an electrical signal to flow from a source (not shown) into contact pads  140 , through traces and/or vias in flexible printed circuit  136 , through contact pads  138 , through leads  134  and into coil  132 . It will be understood by those in the art, that in various embodiments, the electrical connection between leads  134  and flexible printed circuit  136  may be accomplished in a variety of ways known in the art, for example, by inserting leads  134  into an electrical connector affixed to flexible printed circuit  136 . 
         [0035]    Unlike prior art micro speaker  10  shown in  FIGS. 1, 2A, and 2B , micro speaker  110  does not require contact pads  92   t  and contact pads  92   b  to be included in frame  90 . By eliminating the additional components required to transmit the electrical signal from the source to coil  132 , the size may be reduced, the component and manufacturing costs may be reduced, and durability and sound quality may be increased for speaker  110  as compared to prior art speaker  10 . For example, by connecting leads  134  directly to contact pads  138  of flexible printed circuit  136 , the number of electrical connections are reduced to one for each lead  134 . 
         [0036]    As shown in  FIGS. 3 and 4 , leads  134  of coil  132  extend from the side of coil  132  proximate flexible printed circuit  136  and each lead  134  forms a short loop. This allows leads  134  to be shorter in length than leads  34  of prior art micro speaker  10 . However, in other embodiments, for example, leads  134  of coil  132  may extend from the side of coil  132  distal flexible printed circuit  136  and loop inward to be electrically connected to contact pads  138  of flexible printed circuit  136 . As shown, leads  134  extend from the bottom of coil  132  and may be substantially horizontal and substantially in-plane with flexible printed circuit  136  when coil is in the rest position. In various embodiments, speaker  110  may also include one or more of the support members for supporting coil  132  and/or leads  134  as described in U.S. Provisional Application 62/147,801, filed on Apr. 15, 2015, entitled “Speaker with Supported Coil Wire,” the entirety of which is incorporated by reference herein. 
         [0037]    Due to the direct electrical connection between leads  134  and flexible printed circuit  136 , the frame  90  of prior art micro speaker  10  may be replaced with collar  116  as shown in  FIG. 3 . Collar  116  has a first portion  118  that is substantially horizontal and substantially parallel with pot plate  180 . A substantially rectangular opening  120  is provided in first portion  118  through which coil  132  may translate during operation of speaker  110 . First portion  118  serves as a rim to which the perimeter of membrane  112  is affixed typically, for example, by glue or adhesive. Extending downward and substantially perpendicular from the sides of first portion  118  of collar  116  is a second portion, shown as side tabs  122 . Preferably, collar  116  includes four (4) side tabs; however, it will be understood that, in various embodiments, for example, collar  116  may include from about two (2) tabs to about four (4) tabs (e.g., two (2) tabs, three (3) tabs, four (4) tabs). In other embodiments, collar  116  may include less than two (2) tabs. In yet other embodiments, collar  116  may include more than four (4) tabs. 
         [0038]    With continued reference to  FIG. 3 , collar  116  further includes openings  124  proximate the corners of collar  116  between tabs  122 . Preferably, collar  116  includes four (4) openings; however, it will be understood that, in various embodiments, for example, collar  116  may include from about two (2) openings to about four (4) openings (e.g., two (2) openings, three (3) openings, four (4) openings). In other embodiments, collar  116  may include less than two (2) openings. In yet other embodiments, collar  116  may include more than four (4) openings. Openings  124  serve as side vents which permit airflow between a back volume (not shown) and the back volume side of membrane  112 . As illustrated in  FIGS. 3 and 5 , openings  124  are substantially aligned with the gaps  156  between magnets  154  of magnet system  150  and thus speaker  110  includes a substantially clear air pathway between the back volume and the back volume side of membrane  112 . Therefore, openings  124  permit an undistorted vibration of membrane  112  in response to the electrical signal fed into coil  132 . With the inclusion of openings  124  on collar  116 , back vents are not required in pot plate  180 . By not requiring back vents on pot plate  180 , the geometry and/or features of pot plate  180  can be simplified as compared to pot plate  80  of prior art speakers, thus reducing component cost. It will be understood however, that in various embodiments, in addition to or alternative to openings on collar  116 , back vents may be provided on pot plate  180 . 
         [0039]    Collar  116  further includes a stabilizing tab  126  extending substantially horizontally from right tab  122 . As shown in  FIG. 5 , stabilizing tab  126  interfaces with flexible printed circuit  136 , serves to stabilize flexible printed circuit  136 , provides protection between the electrical connection between leads  134  and contact pads  138 , and maintains the positions of collar  116  and coil assembly  130  in speaker  110 . Stabilizing tab  126  is affixed to flexible printed circuit  136  using an adhesive  142  (see  FIG. 3 ), such as, for example, glue, tape, or other adhesives known in the art. 
         [0040]    The assembled speaker  110  is shown in  FIG. 5 . Now with reference to  FIG. 6 , an embodiment of assembling speaker  110  is illustrated. At step  600 , leads  134  of coil  132  are soldered to contact pads  138  of flexible printed circuit  136  to form coil assembly  130 . At step  602 , coil assembly  130  is placed inside perimeter magnet assembly  152 , with leads  134  looping around the right magnet  154  of perimeter magnet assembly  152 . At step  604 , collar  116  is placed on top of and around perimeter magnet assembly  152  and support tab  126  of collar  116  is affixed to flexible printed circuit  136  of coil assembly  130 . At step  606 , pot plate  180  with center magnet assembly  160  is affixed to magnets  154  of perimeter magnet assembly  152  on opposite side of ring plate  158 . At step  608 , the perimeter of membrane  112  is affixed to ring plate  158  and coil  132  is affixed to membrane  112 . This method results in assembled speaker  110  as shown in  FIG. 5 . While various steps are described herein in one order, it will be understood that other embodiments of the method can be carried out in any order and/or without all of the described steps without departing from the scope of the invention. 
         [0041]    Assembled speaker  110 , may be installed in an enclosure  190  as shown in  FIG. 7 . Enclosure  190  is illustrated with a sound path terminating in a side firing port  192 ; however, it will be understood that in various embodiments, the enclosure of speaker  110  may include a sound path terminating in a top or bottom firing port. Enclosure  190  further includes a passageway through which flexible printed circuit  136  exits so that it may be connected to circuitry source (not shown) for driving speaker  110 . 
         [0042]    Another embodiment of speaker  210  of the invention is illustrated in  FIGS. 8A, 8B  and are described below. Some features of one or more of speakers  110  and  210  are common to one another and, accordingly, descriptions of such features in one embodiment should be understood to apply to other embodiments. Furthermore, particular characteristics and aspects of one embodiment may be used in combination with, or instead of, particular characteristics and aspects of another embodiment. 
         [0043]    With reference to  FIG. 8A , a portion of speaker  210  is shown. Speaker  210  comprises a membrane  112 , a collar  216 , a coil assembly  130 , a magnet system  150 , and a pot plate  180 . Speaker  210  is substantially the same as speaker  110  except for the design of collar  216 . collar  216  has a first portion  218  that is substantially horizontal and substantially parallel with pot plate  180  (see  FIG. 8B ). A substantially rectangular opening  220  is provided in first portion  218  through which coil  132  may translate during operation of speaker  210 . First portion  218  serves as a rim to which the perimeter of membrane  112  is affixed typically, for example, by glue or adhesive. Extending downward and substantially perpendicular from the sides of first portion  218  of collar  216  is a second portion, shown as sidewall  222 . Sidewall  222  extends around the perimeter of collar  216 . 
         [0044]    With continued reference to  FIG. 8A , sidewall  222  includes a population of openings  224  extending through sidewall  222  proximate the corners of collar  216 . Openings  224  are shown as substantially circular holes arranged in rows and columns. In various embodiments, for example, openings  224  may be laser cut into sidewall  222 . Openings  224  serve as side vents which permit airflow between a back volume (not shown) and the back volume side of membrane  112 . As illustrated in  FIG. 8A , openings  224  are substantially aligned with the gaps between magnets  154  of magnet system  150  and thus speaker  210  includes a substantially clear air pathway between the back volume and the back volume side of membrane  112 . Therefore, openings  224  permit an undistorted vibration of membrane  112  in response to the electrical signal fed into coil  132 . With the inclusion of openings  224  on collar  216 , back vents are not required in pot plate  180  as shown in  FIG. 8B . By not requiring back vents on pot plate  180 , the geometry and/or features of pot plate  180  can be simplified as compared to pot plate  80  of prior art speakers, thus reducing component cost. It will be understood however, that in various embodiments, in addition to or alternative to openings on collar  216 , back vents may be provided on pot plate  180 . 
         [0045]    It will be understood that the number and/or the size of openings  224  may be altered to provide the appropriate side venting to a back volume (not shown) to achieve the desired acoustic performance for speaker  210 . Furthermore, as described in U.S. Provisional Application filed on Oct. 6, 2015, having Attorney Docket Number 112256-0090, entitled “Electroacoustic Transducer,” the entirety of which is incorporated by reference, openings  224  may have a maximum dimension smaller than an adsorber material filled into an enclosure. The adsorber material may be, for example, the zeolite material described in U.S. Published Patent Application 2013/0170687, published on Jul. 4, 2013, entitled “Loudspeaker System with Improved Sound.” 
         [0046]    Collar  216  further includes a stabilizing tab  226  extending substantially horizontally from sidewall  222 . As shown in  FIG. 8A , stabilizing tab  226  interfaces with flexible printed circuit  136 , serves to stabilize flexible printed circuit  136 , provides protection between the electrical connection between leads  134  and contact pads  138 , and maintains the positions of collar  216  and coil assembly  130  in speaker  210 . Stabilizing tab  226  is affixed to flexible printed circuit  136  using an adhesive  142  (see  FIG. 3 ), such as, for example, glue, tape, or other adhesives known in the art. 
         [0047]    Another embodiment of collar  316  of the invention is illustrated in  FIGS. 9A, 9B  and are described below. Some features of one or more of collars  216  and  316  are common to one another and, accordingly, descriptions of such features in one embodiment should be understood to apply to other embodiments. Furthermore, particular characteristics and aspects of one embodiment may be used in combination with, or instead of, particular characteristics and aspects of another embodiment. 
         [0048]    Collar  316  has a first portion  318  that is substantially horizontal and substantially parallel with a pot plate  180 . A substantially rectangular opening  320  is provided in first portion  318  through which a coil  132  may translate during operation of a speaker  110 . First portion  318  serves as a rim to which the outer perimeter of a membrane  112  is affixed typically, for example, by glue or adhesive. Extending downward and substantially perpendicular from the sides of first portion  318  of collar  316  is a second portion, shown as sidewall  322 . Sidewall  322  extends around the perimeter of collar  316 . 
         [0049]    Sidewall  322  includes a population of openings  324  extending through sidewall  322  proximate the corners of collar  316 . Openings  324  are shown as slots arranged in columns. The slot openings  324  are shown as extending from the terminal end of sidewall  322  up toward first portion  318  of collar  316 . In various embodiments, for example, openings  324  may be laser cut into sidewall  322 . Openings  324  serve as side vents which permit airflow between a back volume (not shown) and the back volume side of a membrane  112 . Openings  324  may be substantially aligned with the gaps between magnets  154  of magnet system  150  and thus a speaker may include a substantially clear air pathway between the back volume and the back volume side of membrane  112 . Therefore, openings  324  permit an undistorted vibration of membrane  112  in response to the electrical signal fed into coil  132 . With the inclusion of openings  324  on collar  316 , back vents are not required in pot plate  180  as shown in  FIG. 8B . By not requiring back vents on pot plate  180 , the geometry and/or features of pot plate  180  can be simplified as compared to pot plate  80  of prior art speakers, thus reducing component cost. It will be understood however, that in various embodiments, in addition to or alternative to openings on collar  316 , back vents may be provided on pot plate  180 . 
         [0050]    Collar  316  further includes a stabilizing tab  326  extending substantially horizontally from sidewall  322 . Stabilizing tab  326  functions the same as stabilizer tab  226  shown in  FIG. 8A . Stabilizing tab  326  interfaces with flexible printed circuit  136 , serves to stabilize flexible printed circuit  136 , provides protection between the electrical connection between leads  134  and contact pads  138 , and maintains the positions of collar  316  and coil assembly  130  in the speaker. Stabilizing tab  326  is affixed to flexible printed circuit  136  using an adhesive  142  (see  FIG. 3 ), such as, for example, glue, tape, or other adhesives known in the art. 
         [0051]    While embodiments of the audio transducer are shown and described as having a rectangular shape, it will be understood that in other embodiments, the audio transducer may have a variety of shapes, including, but not limited to, circular and ovular. Accordingly, the invention is not limited to audio transducers having a rectangular shape. 
         [0052]    In closing, it should be noted that the invention is not limited to the above mentioned embodiments and exemplary working examples. Further developments, modifications and combinations are also within the scope of the patent claims and are placed in the possession of the person skilled in the art from the above disclosure. Accordingly, the techniques and structures described and illustrated herein should be understood to be illustrative and exemplary, and not limiting upon the scope of the present invention. The scope of the present invention is defined by the appended claims, including known equivalents and unforeseeable equivalents at the time of filing of this application.