Patent Abstract:
Electro-dynamic loudspeakers typically include a diaphragm having a conductor applied to one of its surfaces. The diaphragm is secured to a frame. The conductor is connected to a power supply for providing electrical current through linear traces of the conductor that interact with magnetic fields generated by magnets that are mounted to the frame. The diaphragm is driven by a motive force created when current passes through the conductor within the magnetic field. The electrical current is varied to create an acoustical output from the electro-dynamic loudspeaker. Different methods of tensioning the diaphragm are provided for simplifying the manufacturing process and for assuring proper diaphragm tension.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/380,001, filed on May 2, 2002; U.S. Provisional Application No. 60/378,188, filed on May 6, 2002; and U.S. Provisional Application No. 60/391,134, filed on Jun. 24, 2002. The disclosures of the above applications are incorporated herein by reference. 
     This application incorporates by reference the disclosures of each of the following co-pending applications which have been filed concurrently with this application: U.S. patent application Ser. No. 10/428,313, entitled “Mounting Bracket System,” filed May 2, 2003; U.S. patent application Ser. No. 10/428,316, entitled “Film Attaching System,” filed May 2, 2003; U.S. patent application Ser. No. 10/429,228, entitled “Electrical Connectors for Electro-Dynamic Loudspeakers,” filed May 2, 2003; U.S. patent application Ser. No. 10/428,314, entitled “Electro-Dynamic Loudspeaker Mounting System,” filed May 2, 2003; U.S. patent application Ser. No. 10/429,173, entitled “Conductors for Electro-Dynamic Loudspeakers,” filed May 2, 2003; U.S. patent application Ser. No. 10/429,164, entitled “Frame Structure,” filed May 2, 2003; U.S. patent application Ser. No. 10/429,289, entitled “Acoustically Enhanced Electro-Dynamic Loudspeakers,” filed May 2, 2003; U.S. patent application Ser. No. 10/429,162, entitled “Directivity Control Of Electro-Dynamic Loudspeakers,” filed May 2, 2003; U.S. Patent application Ser. No. 10/429,243, entitled “Frequency Response Enhancements For Electro-Dynamic Loudspeakers,” filed May 2, 2003; and U.S. patent application Ser. No. 10/429,163, entitled “Magnet Arrangement for Loudspeaker,” filed May 2, 2003. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention relates to electro-dynamic loudspeakers, and more particularly, to improvements for electro-dynamic loudspeakers and related manufacturing methods. 
     2. Related Art 
     The general construction of an electro-dynamic loudspeaker includes a diaphragm, in the form of a thin film, attached in tension to a frame. An electrical circuit, in the form of electrically conductive traces, is applied to the surface of the diaphragm. Magnetic sources, typically in the form of permanent magnets, are mounted adjacent to the diaphragm or within the frame, creating a magnetic field. When current is flowing in the electrical circuit, the diaphragm vibrates in response to the interaction between the current and the magnetic field. The vibration of the diaphragm produces the sound generated by the electro-dynamic loudspeaker. 
     Many design and manufacturing challenges present themselves in the manufacturing of electro-dynamic loudspeakers. First, the diaphragm, that is formed by a thin film, needs to be permanently attached, in tension, to the frame. Correct tension is required to optimize the resonance frequency of the diaphragm. Optimizing diaphragm resonance extends the bandwidth and reduces sound distortion of the loudspeaker. 
     The diaphragm is driven by the motive force created when current passes through the conductor applied to the diaphragm within the magnetic field. The conductor on the electro-dynamic loudspeaker is attached directly to the diaphragm. Because the conductor is placed directly onto the thin diaphragm, the conductor should be constructed of a material having a low mass and should also be securely attached to the film at high power (large current) and high temperatures. 
     The frame of the electro-dynamic loudspeaker supports the magnets, the diaphragm, and the terminal. The frame presents its own design challenges. The frame must be capable of being bonded to the diaphragm film. The frame must be rigid enough to maintain the diaphragm film in uniform tension and not be susceptible to deforming during handling, assembly, or over time. A ferrous frame has the advantage of being capable of carrying magnetic energy or flux. That feature provides an efficiency advantage over a non-ferrous frame. The frame also should be capable of withstanding high environmental temperatures, humidity, salt spray, etc. 
     Other features affecting the acoustic characteristics of the electro-dynamic loudspeaker include damping of undriven portions of the diaphragm film in order to help reduce distortion and smooth frequency response. Damping is required to control the edges of the diaphragm film by reducing undesired vibration. 
     Accordingly, designing conductors for electro-dynamic loudspeaker applications presents various challenges such as selecting the speaker with the desired audible output for a given location that will fit within the size and location constraints of the desired applications environment. Electro-dynamic loudspeakers exhibit a defined acoustical directivity pattern relative to each speaker&#39;s physical shape and the frequency of the audible output produced by each loudspeaker. Consequently, when an audio system is designed, loudspeakers possessing a desired directivity pattern over a given frequency range are selected to achieve the intended performance of the system. Different loudspeaker directivity patterns may be desirable for various loudspeaker applications. For example, for use in a consumer audio system for a home listening environment, a wide directivity may be preferred. In the application of a loudspeaker, a narrow directivity may be desirable to direct sound, e.g., voice, in a predetermined direction. 
     Often, space limitations in the listening environment prohibit the use of a loudspeaker in an audio system that possesses the preferred directivity pattern for the system&#39;s design. For example, the amount of space and the particular locations available in a listening environment for locating and/or mounting the loudspeakers of the audio system may prohibit the use of a particular loudspeaker that exhibits the intended directivity pattern. Also, due to space and location constraints, it may not be possible to position or oriented the desired loudspeaker in a manner consistent with the loudspeaker&#39;s directivity pattern. Consequently, size and space constraints of a particular environment may make it difficult to achieve the desired performance from the audio system. An example of a listening environment having such constraints is the interior passenger compartment of an automobile or other vehicle. 
     While the electric circuitry of electro-dynamic loudspeakers may present design challenges, electro-dynamic loudspeakers are very desirable loudspeakers because they are designed to have a very shallow depth. With this dimensional flexibility, electro-dynamic loudspeakers may be positioned at locations where conventional loudspeakers would not traditionally fit. This dimensional flexibility is particularly advantageous in automotive applications where positioning a loudspeaker at a location that a conventional loudspeaker would not otherwise fit could offer various advantages. Further, because the final loudspeaker assembly may be mounted on a vehicle, it is important that the assembly be rigid during shipping and handling so that the diaphragm or frame does not deform during installation. 
     While conventional electro-dynamic loudspeakers are shallow in depth and may therefore be preferred over conventional loudspeakers for use in environments requiring thin loudspeakers, electro-dynamic loudspeakers have a generally rectangular planar radiator that is generally relatively large in height and width to achieve acceptable operating wavelength sensitivity, power handling, maximum sound pressure level capability and low-frequency bandwidth. Unfortunately, the large rectangular size results in a high-frequency beam width angle or coverage that may be too narrow for its intended application. The high-frequency horizontal and vertical coverage of a rectangular planar radiator is directly related to its width and height in an inverse relationship. As such, large radiator dimensions exhibit narrow high-frequency coverage and vice versa. 
     SUMMARY 
     The invention provides various fixtures and related film tensioning methodologies related to electro-dynamic loudspeakers. A diaphragm is attached to a frame of an electro-dynamic loudspeaker. The frame is subsequently deformed to elongate and tension diaphragm. 
     Another fixture uses a film clamp to temporarily fix a diaphragm in a non-tensioned state. The diaphragm is placed in the non-tensioned state by placing the diaphragm on a vacuum source having a flat contact surface. The clamp is structured to contact the diaphragm along a perimeter portion and allow access to a center portion of the diaphragm. The clamped diaphragm is then displaced over a loudspeaker frame to produce tension in the diaphragm. Once the proper tension has been produced, the diaphragm is fixed to the frame. 
     Tension in a diaphragm for an electro-dynamic loudspeaker may be controlled through the use of a feedback control system. One type of feedback control system excites the diaphragm during the tensioning process. The actual resonance frequency during tensioning is compared to a target resonance frequency. Once the target resonance frequency has been reached, the tensioning process is completed. Another type of feedback system involves measuring a deflection of the diaphragm under a prescribed load. Tension in the diaphragm is varied until the actual deflection of the diaphragm matches a target deflection of the diaphragm. 
     A tensioning apparatus may also utilize a diaphragm having a spider with a plurality of fingers radially extending from a hub where each of the fingers includes a pad adapted to contact one side of the diaphragm while a base plate contacts an opposite side of the diaphragm. An axial force is placed upon the spider. The axial force is at least partially converted to a lateral force in the diaphragm to produce a tension in the diaphragm between the pads. 
     Also, a diaphragm may be tensioned by placing the diaphragm between a first plate and a second plate where each of the plates includes an aperture extending through its thickness and an annular groove circumscribing the aperture. The first and second plates are drawn toward one another to tension the film. The electro-dynamic loudspeaker frame is coupled to the diaphragm while tension is maintained in the diaphragm. 
     Also, a diaphragm may be tensioned by elastically deforming a frame of the electro-dynamic loudspeaker and coupling a diaphragm to the frame while the load is maintained on the frame. The load on the frame is released to tension the diaphragm. 
     The electro-dynamic loudspeaker assembly system may include a frame loading station, an adhesive application station, a magnet placing station, a curing station, a magnetization station, a diaphragm adhesive application station, a diaphragm placing station, an edge treatment application station, a film tensioning and adhesive curing station, an electrical terminal installation station, a diaphragm cutting station, a clamp repositioning station and an acoustical testing station. 
     Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views. 
         FIG. 1  is a perspective view of an electro-dynamic loudspeaker as it would appear with the grille removed. 
         FIG. 2  is an exploded perspective view of the electro-dynamic loudspeaker shown in  FIG. 1  having a grille. 
         FIG. 3  is a cross-sectional view of the electro-dynamic loudspeaker taken along line  3 - 3  of  FIG. 1 . 
         FIG. 4  is an enlarged cross-sectional view of the encircled area of  FIG. 3 . 
         FIG. 5  is a plan view showing a conductor on a diaphragm of an electrodynamic loudspeaker. 
         FIG. 6  is a plan view of a vacuum platen for use in constructing an electrodynamic loudspeaker. 
         FIG. 7  is a cross-sectional side view of the vacuum platen shown in  FIG. 6 . 
         FIG. 8  is a perspective view of a clamp assembly for use in constructing of an electro-dynamic loudspeaker. 
         FIG. 9  is a cross-sectional side view of the clamp assembly of  FIG. 8 . 
         FIG. 10  is a plan view of the clamp assembly in a closed position. 
         FIG. 11  is a cross-sectional side view of the clamp assembly in the closed position. 
         FIG. 12  is a plan view of an assembly fixture for assembling an electrodynamic loudspeaker. 
         FIG. 13  is a cross-sectional side view of the assembly fixture. 
         FIG. 14  is a plan view of the clamp assembly positioned atop the assembly fixture. 
         FIG. 15  is a cross-sectional side view of the closed clamp assembly positioned atop the assembly fixture. 
         FIG. 16  is cross-sectional side view of a work-in-process electro-dynamic loudspeaker. 
         FIG. 17  is a cross-sectional side view of a finished electro-dynamic loudspeaker. 
         FIG. 18  is a cross-sectional view of a film tensioning device constructed in accordance with the teachings of the invention. 
         FIG. 19  is a cross-sectional side view of an alternate film tensioning device. 
         FIG. 20  is a perspective view of an alternate tensioning member. 
         FIG. 21  is a cross-sectional side view depicting use of the alternate tensioning member shown in  FIG. 20 . 
         FIG. 22  is a cross-sectional side view further depicting diaphragm tensioning using the alternate tensioning member of  FIG. 20 . 
         FIG. 23  depicts a frame in an undeformed state and a deformed state. 
         FIG. 24  is a plan view of an electro-dynamic loudspeaker assembly system. 
         FIG. 25  is a perspective view of a pallet for use in the assembly system. 
         FIG. 26  is a perspective view of an adhesive application station. 
         FIG. 27  is a perspective view of a magnet loading and adhesive activator application station. 
         FIG. 28  is a perspective view of a magnetization station. 
         FIG. 29  is a perspective view of an adhesive application station. 
         FIG. 30  is a perspective view of a diaphragm loading station. 
         FIG. 31  is a cross-sectional view of speaker components and fixturing located after completing diaphragm loading as depicted in  FIG. 30 . 
         FIG. 32  is a perspective view of an edge treatment compound application station. 
         FIG. 33  is a perspective view of a clamping and irradiation station. 
         FIG. 34  is a perspective view of a terminal crimping station. 
         FIG. 35  is a perspective view of a diaphragm trimming station. 
         FIG. 36  is a perspective view of the pallet having a lower clamp frame and an upper clamp frame positioned thereon. 
         FIG. 37  is a perspective view of a felt cutting and loading station. 
         FIG. 38  is a perspective view of a frame loading station. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view of an electro-dynamic loudspeaker  100  of the invention. As shown in  FIG. 1 , the electro-dynamic loudspeaker is a generally planar loudspeaker having a frame  102  with a diaphragm  104  attached in tension to the frame  102 . A conductor  106  is positioned on the diaphragm  104 . The conductor  106  is shaped in serpentine fashion having a plurality of substantially linear sections (or traces)  108  longitudinally extending along the diaphragm interconnected by radii  110  to form a single current path. Permanent magnets  202  (shown in  FIG. 2 ) are positioned on the frame  102  underneath the diaphragm  104 , creating a magnetic field. 
     Linear sections  108  are positioned within the flux fields generated by permanent magnets  202 . The linear sections  108  carry current in a first direction  112  and are positioned within magnetic flux fields having similar directional polarization. Linear sections  108  of conductor  106  having current flowing in a second direction  114 , that is opposite the first direction  112 , are placed within magnetic flux fields having an opposite directional polarization. Positioning the linear sections  108  in this manner assures that a driving force is generated by the interaction between the magnetic fields developed by magnets  202  and the magnetic fields developed by current flowing in conductor  106 . As such, an electrical input signal traveling through the conductor  106  causes the diaphragm  104  to move, thereby producing an acoustical output. 
       FIG. 2  is an exploded perspective view of the electro-dynamic loudspeaker  100  shown in  FIG. 1 . As illustrated in  FIG. 2 , the flat panel loudspeaker  100  includes a frame  102 , a plurality of high energy magnets  202 , a diaphragm  104 , an acoustical dampener  236  and a grille  228 . Frame  102  provides a structure for fixing magnets  202  in a predetermined relationship to one another. In the depicted embodiment, magnets  202  are positioned to define five rows of magnets  202  with three magnets  202  in each row. The rows are arranged with alternating polarity such that fields of magnetic flux are created between each row. Once the flux fields have been defined, diaphragm  104  is fixed to frame  102  along its periphery. 
     A conductor  106  is coupled to the diaphragm  104 . The conductor  106  is generally formed as an aluminum foil bonded to the diaphragm  104 . The conductor  106  can, however, be formed from other conductive materials. The conductor  106  has a first end  204  and a second end  206  positioned adjacent to one another at one end of the diaphragm  104 . 
     As shown in  FIG. 2 , frame  102  is a generally dish-shaped member preferably constructed from a substantially planar contiguous steel sheet. The frame  102  includes a base plate  208  surrounded by a wall  210 . The wall  210  terminates at a radially extending flange  212 . The frame  102  further includes apertures  214  and  216  extending through flange  212  to provide clearance and mounting provisions for a conductor assembly  230 . 
     Conductor assembly  230  includes a terminal board  218 , a first terminal  220  and a second terminal  222 . Terminal board  218  includes a mounting aperture  224  and is preferably constructed from an electrically insulating material such as plastic, fiberglass or other insulating material. A pair of rivets or other connectors (not shown) pass through apertures  214  to electrically couple first terminal  220  to first end  204  and second terminal  222  to second end  206  of conductor  106 . A fastener such as a rivet  226  extends through apertures  224  and  216  to couple conductor assembly  230  to frame  102 . 
     A grille  228  functions to protect diaphragm  104  from contact with objects inside the listening environment while also providing a method for mounting loudspeaker  100 . The grille  228  has a substantially planar body  238  having a plurality of apertures  232  extending through the central portion of the planar body  238 . A rim  234  extends downward, substantially orthogonally from body  238 , along its perimeter and is designed to engage the frame  102  to couple the grille  228  to the frame  102 . 
     An acoustical dampener  236  is mounted on the underside of the base plate  208  of the frame  102 . Dampener  236  serves to dissipate acoustical energy generated by diaphragm  104  thereby minimizing undesirable amplitude peaks during operation. The dampener  236  may be made of felt, or a similar gas permeable material. 
       FIG. 3  is a cross-sectional view of the electro-dynamic loudspeaker taken along line  3 - 3  of  FIG. 1 .  FIG. 3  shows the frame  102  having the diaphragm  104  attached in tension to the frame  102  and the permanent magnets  202  positioned on the frame  102  underneath the diaphragm  104 . Linear sections  108  of the conductor  106  are also shown positioned on top of the diaphragm  104 . 
       FIG. 4  is an enlarged cross-sectional view of the encircled area of  FIG. 3 . As illustrated by  FIG. 4 , the diaphragm  104  is comprised of a thin film  400  having a first side  402  and a second side  404 . First side  402  is coupled to frame  102 . Generally, the diaphragm  104  is secured to the frame  102  by an adhesive  406  that is curable by exposure to radiation. However, the diaphragm  104  may secured to the frame  102  by other mechanism, such as those known in the art. 
     To provide a movable membrane capable of producing sound, the diaphragm  104  is mounted to the frame in a state of tension and spaced apart a predetermined distance from magnets  202 . The magnitude of tension of the diaphragm  104  depends on the speaker&#39;s physical dimensions, materials used to construct the diaphragm  104  and the strength of the magnetic field generated by magnets  202 . Magnets  202  are generally constructed from a highly energizable material such as neodymium iron boron (NdFeB), but may be made of other magnetic materials. The thin diaphragm film  400  is generally a polyethylenenaphthalate sheet having a thickness of approximately 0.001 inches; however, the diaphragm film  400  may be formed from materials such as polyester (e.g., known by the tradename “Mylar”), polyamide (e.g., known by the tradename “Kapton”) and polycarbonate (e.g., known by the tradename “Lexan”), and other materials known by those skilled in the art for forming diaphragms  104 . 
     The conductor  106  is coupled to the second side  404  of the diaphragm film  400 . The conductor  106  is generally formed as an aluminum foil bonded to diaphragm film  400 , but may be formed of other conductive material known by those skilled in the art. 
     The frame  102  includes a base plate  208  surrounded by a wall  210  extending generally orthogonally upward from the plate  208 . The wall  210  terminates at a radially extending flange  212  that defines a substantially planar mounting surface  414 . A lip  416  extends downwardly from flange  212  in a direction substantially parallel to wall  210 . Base plate  208  includes a first surface  418 , a second surface  420  and a plurality of apertures  422  extending through the base plate  208 . The apertures  422  are positioned and sized to provide air passageways between the first side  402  of diaphragm  104  and first surface  418  of frame  102 . An acoustical dampener  236  is mounted to second surface  420  of frame base plate  208 . 
     Various systems for assembling an example loudspeaker  100  will now be described. A first example system is depicted in  FIGS. 5-17 . The first system includes a vacuum platen  600  ( FIGS. 6-7 ) and a film clamp  800  ( FIGS. 8-9 ). Vacuum platen  600  and film clamp  800  may be used in conjunction with one another to restrain diaphragm  104  ( FIG. 5 ) in a flat position without tension. Once diaphragm  104  is fixed within clamp  800 , film  400  may be subsequently tensioned as will be described later. 
     The initial flattening and clamping of diaphragm  104  may provide the assembler with a known diaphragm state to which tension may be added. Difficulties may arise in attempting to obtain a reproducible tension during subsequent assembly operations when diaphragm  104  is not first placed in a substantially flat, no tension state. This first example system includes vacuum platen  600  and film clamp  800  to achieve a repeatable diaphragm state. In other examples, any other mechanism(s) and/or techniques capable of providing a known diaphragm state to which tension may be added may be used. 
     The example vacuum platen  600  includes a base  700  having a body  702  and a pedestal  704  protruding from a first surface  602  of body  702 . Pedestal  704  includes an upper surface  706  positioned substantially parallel to first surface  602 . A vacuum passageway  708  may extend through pedestal  704  and body  702  to couple upper surface  706  with a vacuum source  604 . A cap  710  may be coupled to pedestal  704  along upper surface  706 . Cap  710  may be constructed from a gas permeable material such as porous aluminum. Base  700  may be constructed from a gas impermeable material. Accordingly, a suction force is created along an upper surface  606  of cap  710  when vacuum source  604  draws a vacuum in vacuum passageway  708 . 
     The example film clamp  800  includes an upper clamp half  802  and a lower clamp half  804  connected by a hinge  806 . The illustrated upper clamp half  802  includes a generally rectangularly shaped body  808  and an elastomeric gasket  810 . Body  808  includes an aperture  900  ( FIG. 9 ) extending through body  808 . Elastomeric gasket  810  includes a similarly shaped aperture  902  ( FIG. 9 ) extending through the thickness of gasket  810 . Elastomeric gasket  810  may be attached to body  808  to provide a compressible high friction surface  812  for engagement with diaphragm  104 . 
     The illustrated lower clamp half  804  is constructed from a generally rectangularly shaped aluminum frame  814  having an aperture  904  extending through the lower clamp half  804 . Lower clamp half  804  includes an upper surface  906  and a lower surface  908 . 
     During the loudspeaker assembly process, film clamp  800  may be positioned on vacuum platen  600  such that pedestal  704  enters aperture  904  of lower clamp half  804  as illustrated in  FIG. 9 . Once seated, upper surface  906  of lower clamp half  804  may be substantially coplanar with upper surface  606  of cap  710 . In order to properly position diaphragm  104 , upper clamp half  802  may be rotated to place film clamp  800  in the open position depicted in  FIG. 8 . 
     With vacuum source  604  turned off, diaphragm  104  may be placed on upper surface  606 . Diaphragm  104  may be aligned relative to lower clamp half  804  using sights  816 . Sights  816  may be visual markings, rods, rings, notches or any other form of alignment mechanism formed on diaphragm  104  to assist in the alignment procedure. The location of sights  816  effectively defines a perimeter portion  818  and a center portion  820  of diaphragm  104 . Center portion  820  may contain most, if not all, of the material which will remain coupled to frame  102  at the completion of the assembly process. 
     Once diaphragm  104  has been properly positioned, vacuum may be supplied to cap  710  via vacuum source  604 . Because cap  710  is constructed from a gas permeable material, diaphragm  104  is forced to closely conform to planar upper surface  606 . While the vacuum source is maintained, upper clamp half  802  may be rotated to place film clamp  800  in a closed position as shown in  FIGS. 10 and 11 . During clamp closure, elastomeric gasket  810  may deform locally to account for the thickness of diaphragm  104 . Latches  822  secure upper clamp half  802  to lower clamp half  804 . It should be appreciated that latches  822  are merely exemplary devices for coupling the clamp halves together and that any number of fastening devices may be implemented. Once upper clamp half  802  is clamped to lower clamp half  804 , vacuum is turned off and film clamp  800  holding diaphragm  104  in an untensioned state is removed from vacuum platen  600 . 
     Frame  102  may be fixtured in an example assembly fixture  1200  ( FIGS. 12 and 13 ). Assembly fixture  1200  may be shaped substantially similarly to vacuum platen  600 . However, assembly fixture  1200  may include a recess  1300  for receipt of a portion of frame  102 . Assembly fixture  1200  includes a gage surface  1302  offset a predetermined distance  1304  from planar mounting surface  408  of frame  102 . In order to apply tension to diaphragm  104 , distance  1304  is greater than the thickness of lower clamp half  804 . The magnitude of tension generated is optimized by defining distance  1304  in concert with the physical characteristics of frame  102  and diaphragm  104 . 
     Diaphragm  104  may be mechanically coupled with frame  102 . For example, adhesive  406  may be applied to planar mounting surface  408  of frame  102 . Adhesive  406  may alternatively be applied to diaphragm  104 . After application of adhesive  406 , film clamp  800  including clamped diaphragm  104  may be positioned on assembly fixture  1200  such that frame  102  enters aperture  904  of lower clamp half  804  ( FIGS. 14 and 15 ). The diaphragm  104  may contact adhesive  406  and planar mounting surface  408  of frame  102 . Contact may occur prior to lower surface  908  of lower clamp half  804  contacting gage surface  1302  of assembly fixture  1200 . To produce the desired tension in film  400 , film clamp  800  is forced down over assembly fixture  1200  so that lower surface  908  engages gage surface  1302 . 
     Depending on the type of adhesive used, a subsequent process may be required. For example, adhesive  406  is curable by exposure to radiation. Accordingly, while film clamp  800  is coupled to assembly fixture  1200 , a radiation source  1500  is energized to cure the adhesive and secure diaphragm  104  to frame  102 . Alternatively, where some other mechanical coupling mechanism is used, appropriate processes may need to be performed. 
     A second example system used to tension the diaphragm of a loudspeaker  100  is described with reference to  FIGS. 16 and 17 . In this system, frame  102  includes an elongated radially extending flange  1600  which does not include a downwardly extending lip. The remaining planar loudspeaker components are substantially similar to those previously described. The assembly process may include positioning diaphragm  104  in a substantially flat, no tension state as previously described. However, it should be appreciated that the flattening and clamping steps are not necessarily required to construct planar loudspeaker according to this system. Similarly, alternate tensioning methods that are described are not intended to be limited to include the flattening and clamping process. 
     A bead of adhesive  406  may be applied along the periphery of either or both frame  102  and diaphragm  104 . Diaphragm  104  may then be aligned with and bonded to frame  102  via adhesive  406 . As noted earlier, adhesive  406  may be a light curable material or any other suitable bonding agent which may affix the dissimilar materials to one another. Similarly, adhesive  406  may any other coupling mechanism to mechanically couple the diaphragm  104  to the frame  102 . 
     Radially extending flange  1600  may be mechanically deformed by bending an outer peripheral region down from line  1700  as shown in  FIG. 17  to tension diaphragm  104 . Line  1700  acts as a fulcrum around the perimeter of frame  102  about which diaphragm  104  is stretched. The proper diaphragm tension may be obtained in a variety of ways. For example, if diaphragm  104  was initially coupled to frame  102  in a substantially flat, non-tension state, a deflection distance  1702  may be empirically determined by testing. Once the proper deflection distance is determined, hard tooling may be created to repeatably deform frame  102  and move radially extending flange  1600  the predetermined deflection distance  1702  during the assembly of each loudspeaker  100 . 
     Another example system of assuring proper film tension includes a feedback system  1602 . One example feedback system may involve placing a known load at the center of diaphragm  104  and measuring the deflection of the diaphragm at the load application point. The desired deflection per load may be empirically determined by testing where the resonance frequency of diaphragm  104  is plotted against deflection per a given load. Once the desired resonance frequency is determined for a given speaker geometry, a target diaphragm deflection per given load may be determined. The feedback system may operate by measuring the actual diaphragm deflection at a known load with a deflection sensor  1604 . The measured actual deflection may be compared to the target deflection. 
     Frame  102  may be deformed until the measured deflection is substantially equal to the target deflection, thereby properly tensioning diaphragm  104  to produce the desired resonance frequency. Logic control systems such as proportional, integral, derivative closed feedback loops, etc. may be implemented to control the mechanical deflection of frame  102  during the tensioning process. Such a control system may provide a high degree of repeatability regarding film tensioning. 
     Another example feedback system  1704  may directly measure resonance frequency during film tensioning using a frequency sensor  1706 . In this control scheme, diaphragm  104  may be repeatedly excited and the resonance frequency measured. The measured frequency may be compared to a desired target frequency during film tensioning. Frame  102  may be deformed until the measured resonance frequency matches the target frequency within an acceptable tolerance. It should be appreciated that the feedback systems described may be used with any of the tensioning techniques described. 
     Yet another film tensioning system will be described in greater detail with reference to  FIG. 18 . An example film tensioner  1800  includes an upper plate  1802  and a lower plate  1804 . Plates  1802  and  1804  have matching beveled apertures  1806  and  1808 , respectively. Center portion  820  of diaphragm  104  is positioned within the openings defined by apertures  1806  and  1808 . Apertures  1806  and  1808  may be sized and shaped slightly larger than frame  102  to allow insertion of frame  102  within one of the apertures  1806  and  1808 . 
     Upper plate  1802  may include an annular groove  1810  having an asymmetrical cross-section as shown in  FIG. 18 . Lower plate  1804  may include an annular groove  1812  shaped as the mirror image of groove  1810 . A first elastomeric member  1814  may be positioned within groove  1810  and a second elastomeric member  1816  may be positioned within groove  1812 . Grooves  1810  and  1812  may be shaped to constrain movement of the elastomeric members  1814  and  1816  toward apertures  1806  and  1808 , respectively. In addition, grooves  1810  and  1812  may be shaped to allow movement of elastomeric members  1814  and  1816  away from apertures  1806  and  1808 . Specifically, the annular grooves  1810  and  1812  may be shaped to impart a lateral force to center portion  820  of diaphragm  104  when an axial force is applied to upper plate  1802  and lower plate  1804  drawing them toward one another. 
     Upper plate  1802  may also include threaded apertures  1818 . Stepped apertures  1820  extend through lower plate  1804 . Threaded fasteners  1822 , which are illustrated as bolts, may be inserted in apertures  1820  and tightened into threaded apertures  1818  to draw upper plate  1802  and lower plate  1804  together. It should be appreciated that upper plate  1802  and lower plate  1804  may be drawn together using a variety of mechanisms such as toggle clamps, jack screws, hydraulic cylinders or any other known clamping and force producing devices. 
     In this example technique, the film may first be tensioned by drawing upper plate  1802  and lower plate  1804  together. Adhesive  406  (or some other coupling mechanism) may be placed on the tensioned portion of diaphragm  104  and/or planar mounting surface  408  of frame  102 . While upper plate  1802  is clamped to lower plate  1804 , frame  102  may be placed into contact with diaphragm  104 . Once the adhesive has cured (or mechanical coupling completed), the threaded fasteners  1822  may be removed and upper plate  1802  may be separated from lower plate  1804 . It should also be appreciated that apertures  1806  and  1808  may be sized to allow entry of light waves to cure adhesive  406 , or to allow manipulation of some other coupling mechanism, if so desired. Depending on the specific configuration of the loudspeaker  100 , perimeter portion  818  of diaphragm  104  may be trimmed to remove any film extending beyond lip  306 . 
     With reference to  FIG. 19 , another example film tensioning technique is depicted. The fixturing used to practice this example technique includes a fixture  1900  having a lower die  1902 , and an upper die  1904 . Fixture  1900  may function to restrain the periphery of diaphragm  104  and define a cavity  1906  between one side of the diaphragm  104  and lower die  1902 . A fluid source  1908  may supply pressurized fluid to cavity  1906 . Because lower die  1902  is constructed from a substantially rigid material, diaphragm  104  may elongate in tension as depicted in  FIG. 19 . Pressure is maintained within cavity  1906  while frame  102  is mechanically coupled with diaphragm  104 . Diaphragm  104  may be secured to frame  102  using any number of previously discussed bonding techniques including mechanical fasteners, radiation curable adhesives, multi-part epoxies, heat curable adhesives or pressure sensitive compounds. 
     After diaphragm  104  has been fixed to frame  102 , upper die  1904  may be removed. If desired, excess diaphragm material extending beyond the perimeter of frame  102  may be removed. 
     In this example technique, some of the initial tension generated by the pressurized fluid may relax during subsequent frame attachment process. Accordingly, a tension greater than the final desired tension may be initially induced via fluid source  1908  to assure that the film is properly tensioned during use. 
       FIGS. 20-22  depict another example of fixturing used to tension diaphragm  104  prior to attaching diaphragm  104  to frame  102 . An example spider  2000  may operate in conjunction with an example base plate  2100  to tension diaphragm  104 . Spider  2000  may be placed on a first side of diaphragm  104  while base plate  2100  may be placed on the opposite side of the diaphragm  104 . Spider  2000  may function by converting an axial force applied in direction  2102  to a lateral tension produced in opposed directions  2200 . 
     The illustrated spider  2000  is a generally pyramidal member having a hub  2002  positioned proximate to a truncated portion of the pyramid. A plurality of legs  2004  angularly extend from hub  2002 . Each of the legs  2004  include a body portion  2006  and a foot portion  2008 . Each foot portion  2008  radially extends from the distal end of each leg  2004 . A pad  2010  is coupled (as shown in  FIG. 20 ) to a lower surface of each foot  2008 . Pads  2010  may be constructed from a high friction, elastomeric material that is suitable for gripping diaphragm  104  without causing damage to diaphragm  104 . 
     The illustrated base plate  2100  is a generally rectangularly-shaped member having an aperture  2104  extending through the base plate  2100 . Aperture  2104  may be shaped similarly to the perimeter of frame  102  and sized such that frame  102  may be inserted into aperture  2104 . Base plate  2100  includes a low friction surface  2106  upon which diaphragm  104  may freely slide. As best shown in  FIG. 21 , each pad  2010  is supported by a portion of base plate  2100 . 
     During tensioning, diaphragm  104  may be placed between base plate  2100  and spider  2000 . An axial force may be applied to spider  2000  in direction  2102 . Due to the angular orientation of legs  2004  relative to low friction surface  2106 , at least some of the axial force applied in direction  2102  may be converted to opposing forces in opposed directions  2200 . The opposed forces may tension diaphragm  104 . After tensioning, frame  102  is mechanically coupled to diaphragm  104  as previously discussed. 
       FIG. 23 , is yet another example system for loudspeaker  100  assembly. In this system, frame  102  may be elastically deformed prior to attachment of diaphragm  104 . The deformed frame  102  is represented in phantom lines at reference numeral  2300 . It should be appreciated that any number of force generating devices or tools such as jack screws, hydraulic rams or other force producing devices may be used to elastically deform frame  102  by inwardly deflecting radially extending flange  304  and lip  306  ( FIG. 3 ) of frame  102 . Frame  102  may be maintained in the deformed state shown as  2300  while diaphragm  104  ( FIG. 1 ) is attached to planar mounting surface  408  ( FIG. 4 ). 
     Once diaphragm  104  has been securely attached to frame  102 , the external forces deforming frame  102  may be released. Because frame  102  was elastically deformed, flange  304  and lip  306  have a tendency to spring-back to their originally undeformed state. This tendency is resisted by diaphragm  104 . Diaphragm  104  elongates as the deformed frame attempts to return to its undeformed state until an equilibrium is reached. Frame  102  may be constructed from steel, aluminum or any number of composite materials capable of being deformed. Materials having a modulus of elasticity less than 29,000 KSI are contemplated to provide a relatively large elastic deformation prior to yield. A large frame deformation is beneficial to account for elongation or deformation of adhesive  406  or other mechanical coupling used to bond diaphragm  104  to frame  102 . 
     An example planar loudspeaker assembly system  2400  is depicted in  FIG. 24 . Planar loudspeaker assembly system  2400  functions to construct a fully tested and finished planar loudspeaker from a variety of separate components in a relatively small space and a minimal amount of time. 
     Assembly system  2400  is a conveyor-type system utilizing a plurality of pallets  2402  traveling about a closed loop. Each of pallets  2402  is engaged by a drive belt or track  2404  to move the pallets  2402  around the loop in a counter-clockwise direction. A plurality of workstations  2406  are positioned along track  2404  to perform the process steps described hereinafter. 
     As best shown in  FIG. 25 , pallet  2402  includes a first protrusion  2500  and a second protrusion  2502  extending upwardly from an upper surface  2504 . First protrusion  2500  includes a recess  2505 . Second protrusion  2502  is rectangularly shaped and surrounds an aperture  2506 . Aperture  2506  extends through the thickness of pallet  2402 . Second protrusion  2502  includes a stepped sidewall  2508 . Stepped sidewall  2508  includes a lower portion  2510 . Stepped sidewall  2508  includes an upper portion  2512  that serves as a locating structure for frame  102 . As shown in  FIG. 36 , an upper clamp half  3600  is placed over first protrusion  2500 . A lower clamp half  3602  is positioned over second protrusion  2502 . 
     With reference to  FIG. 37 , pallet  2402  travels to a felt cutting and loading station  3700 . The felt cutting and loading station  3700  includes a frame  3701 , a dispenser  3702 , a cutter  3704  and a robot  3706  having an end-effector  3708  coupled to robot  3706 . A roll of felt  3710  is rotatably coupled to frame  3701 . The free end of the roll of felt  3710  is fed into dispenser  3702 . Dispenser  3702  is controllable to selectively index a portion of the roll of felt onto a block  3712 . Once the appropriate width of felt has been dispensed on block  3712 , feeder  3702  halts movement of felt roll  3710 . Cutter  3704  separates a singular felt panel  3714  from the roll. At this time, robot  3706  positions end-effector  3708  above felt panel  3714  located on block  3712 . Through the use of vacuum or a cloth gripping device, end-effector  3708  transfers felt panel  3714  to recess  2505  located in first protrusion  2500 . 
     Pallet  2402  travels to a frame loading station  3800  shown in  FIG. 38 . Frame loading station  3800  includes a dial table  3801 , a hot melt applicator  3802  and a robot  3804 . Dial table  3801  includes three stacks  3806  rotatably mounted to a base  3808 . The stack positioned beneath robot  3804  is defined as being in the active position. The other two stacks  3806  are positioned at inactive positions. An operator positioned adjacent inactive stacks  3806  loads frames  102  for later use at the active position. An elevator (not shown) positioned below dial table  3801  maintains the position of the upper most frame within the active stack at a predetermined elevation. 
     During operation of frame loading station  3800 , robot  3804  positions a magnetic or vacuum end-effector  3810  over the active stack position. The end-effector removes the top frame from the active stack and rolls it across hot melt applicator  3802 . Robot  3804  continues to translate frame  102  to a position over felt panel  3714 . Frame  102 , including a coating of hot melt adhesive, is pressed into contact with felt panel  3714  to adhere the felt to the frame. End-effector  3810  then places the frame and felt subassembly on upper portion  2512  of second protrusion  2502 . Operation of frame loading station  3800  continues in this manner until all of the frames within the active stack have been used. At this time, dial table  3801  indexes to place one of the previously inactive stacks at the active stack location. An operator then fills the empty stack  3806  with frames  102 . 
     As shown in  FIG. 26 , pallet  2402  continues to travel in a counter-clockwise direction through an adhesive application station  2600 . Station  2600  includes five adhesive valves  2602  positioned in an offset manner to one another. Pallet  2402  passes under adhesive valves  2602  at a uniform rate. Each adhesive valve  2602  lowers to a dispensing height and applies an adhesive  2604  at an appropriate time to dispense five equally spaced ribbons of adhesive  2604  on frame  102 . The opening and closing of valves  2602  is timed to correspond to the movement of pallet  2402 . Five equal length adhesive ribbons  2604  are dispensed on frame  102  without stopping pallet  2402 . 
     Pallet  2402  continues to travel to a magnet loading station  2700  depicted at  FIG. 27 . At magnet loading station  2700 , a bowl feeder  2702  presents fifteen magnets  202  correctly oriented in a pattern of five rows and three columns. It should be appreciated that other high speed feeding mechanisms may be utilized to correctly present and orient magnets  202 . Referring to  FIG. 27 , an end-effector  2704  is mounted to a robot or pick-and-place mechanism  2706  to allow movement of end effector  2704  within station  2700 . End-effector  2704  is positioned immediately above placed magnets  202  at bowl feeder  2702 . End-effector  2704  is then energized to temporarily couple magnets  202  to end effector  2704 . Robot  2706  then moves end-effector  2704  above an adhesive activator applicator pad  2708 . Each of magnets  202  attached to end-effector  2704  are then pressed against adhesive activator applicator pad  2708  to apply an adhesive activator  2710  to the bottom of magnets  202 . End-effector  2704  along with magnets  202  are next indexed to a location above frame  102 . End-effector  2704  is axially lowered to press magnets  202  into adhesive  2604  and mix adhesive activator  2710  with adhesive  2604  to start the chemical reaction to secure magnets  202  to frame  102 . Adhesive  2604  and adhesive activator  2710  illustratively complete a two-part adhesive. One skilled in the art will appreciate that the two-part adhesive is merely exemplary and that a variety of other magnet bonding methods may be incorporated without departing from the scope of the invention. For example, a one-part heat curable adhesive, mechanical fasteners, or welding techniques may be used. 
     Pallet  2402  next travels along track  2404  to acrylic curing stations  2410 . Pallet  2402  passes through acrylic curing stations  2410  to allow the two-part adhesive time to cure. After magnets  202  are firmly secured to frame  102 , they are magnetized at a magnetizing station  2800 . Within magnetization station  2800 , frame  102  is raised to be within close proximity to an energy source  2802 . Each of the magnets within any one row are magnetized having the same polarity. Magnets of immediately adjacent rows are magnetized with the opposite polarity to create the magnetic flux fields described earlier. After energization, frame  102  and magnets  202  are separated from energy source  2802  via a cylinder  2805  and lowered onto pallet  2402 . Specifically, a plate  2806  including a plurality of posts  2808  are lowered such that two posts  2808  contact each magnet to separate the magnetized magnets and frame from energy source  2802 . 
     After magnetization, pallet  2402  travels to diaphragm adhesive application station  2900  shown in  FIG. 29 . Station  2900  includes an adhesive applicator  2902  mounted to a Cartesian arm  2904 . Adhesive applicator  2902  applies adhesive  406  to planar mounting surface  414  of frame  102 . In the preferred embodiment, movement of pallet  2402  is controlled while adhesive is being applied. Motion control along an X axis will be provided by track  2404  and motion along the Y and Z axes will be provided by Cartesian arm  2904 . 
     Pallet  2402  next travels to a diaphragm loading station  3000 . Diaphragm loading station  3000  loads diaphragm  104  onto frame  102 . In a preferred embodiment, a roll  3002  of diaphragms  104  is rotatably mounted on a frame  3004 . The roll  3002  of diaphragms  104  consists of a continuous sheet of film  400  having a plurality of conductors  106  spaced apart and positioned along the length of film  400 . The continuous sheet of film  400  is rolled for convenient handling in a production environment. A free end of diaphragm roll  3002  is inserted into a feeder  3006 . Feeder  3006  is positioned adjacent a vacuum platen  3008 . During operation, feeder  3006  is selectively operable to dispense material from diaphragm roll  3002  onto an upper surface  3010  of vacuum platen  3008 . A vision system  3012  includes a controller  3014  and a camera  3016 . Camera  3016  is preferably positioned atop frame  3004  to have a clear view of the end portion of diaphragm roll  3002  being positioned on upper surface  3010  of vacuum platen  3008 . Camera  3016  communicates diaphragm position information to controller  3014 . 
     Once the free end of diaphragm roll  3002  has been indexed to a desired position to position a diaphragm  104  on upper surface  3010  of vacuum platen  3008 , controller  3014  instructs feeder  3006  to maintain the current position of the diaphragm roll. Camera  3016  also communicates the lateral position of the conductor  106  on the diaphragm  104  on upper surface  3010  of vacuum platen  3008  to controller  3014 . The position of pallet  2402  is adjusted to align speaker frame  102  with the current position of the conductor  106  on the upper surface  3010  of vacuum platen  3008 . 
     Once the pallet and diaphragm  104  on upper surface  3010  of vacuum platen  3008  have been positioned as described, vacuum is applied to vacuum platen  3008 . As such, the end portion of diaphragm roll  3002  containing diaphragm  104  that is positioned on upper surface  3010  of vacuum platen  3008  is temporarily fixed to vacuum platen  3008 . A cutter  3018  separates diaphragm  104  from diaphragm roll  3002 . 
     After diaphragm  104  is severed from diaphragm roll  3002 , an end-effector  3020  picks up upper clamp half  3600  from its storage position on pallet  2402 . End-effector  3020  positions upper clamp half  3600  on the cut diaphragm while vacuum is supplied to vacuum platen  3008 . End-effector  3020  next supplies vacuum to the perimeter of upper clamp half  3600  as well. The vacuum supply to vacuum platen  3008  is turned off and a slight positive pressure is applied to diaphragm  104  from upper surface  3010  of vacuum platen  3008 . Next, end-effector  3020  transfers upper clamp half  3600  and diaphragm  104  to a position over pallet  2402 . End-effector  3020  then lowers upper clamp half  3600  and diaphragm  104  into contact with lower clamp half  3602  effectively trapping diaphragm  104  between the upper and lower clamp halves in a non-tension state. The vacuum supplied to end-effector  3020  is turned off and end-effector  3020  releases upper clamp half  3600  to complete the cycle at diaphragm loading station  3000 . 
     With reference to  FIG. 31 , pallet  2402  is depicted in cross-section after the process steps conducted at diaphragm loading station  3000  have been completed. At this time, lower clamp half  3602 , diaphragm  104 , and upper clamp half  3600  are suspended on a set of spring plungers  3100 . The weight of upper clamp half  3600  is transferred through an elastomeric seal  3102 , diaphragm  104 , an elastomeric seal  3104  and lower clamp half  3602 . This arrangement maintains diaphragm  104  in a non-tensioned state. Spring plungers  3100  include axially disposable end portions  3106  which are shown in their fully extended positions in  FIG. 31 . End portions  3106  and lower clamp half  3602  are sized to position diaphragm  104  at a plane above the adhesive and frame subassembly. 
     Pallet  2402  next travels to an edge treatment application station  3200 . Edge treatment application station  3200  includes a valve  3202  coupled to a Cartesian arm  3204 . Valve  3202  applies an edge treat compound  3206  to the perimeter of diaphragm  104  as movement of pallet  2402  is controlled within application station  3200 . Motion control along an X axis will be provided by track  2404  and motion along the Y and Z axes will be provided by Cartesian arm  3204 . Edge treat compound  3206  functions to dampen unwanted harmonic or spurious vibrations of diaphragm  104  during speaker operation. Preferably, edge treat compound  3206  is a liquid urethane oligomer acrylic monomer blend such as Dymax 4-20539, that cures to a flexible solid. 
     Pallet  2402  travels next to a film tensioning and adhesive curing station  3300 . At station  3300 , a radiation source  3302  extends downwardly and forces upper clamp half  3600  downward toward lower clamp half  3602 . The reaction force generated from springs within spring plungers  3100  creates a clamping force between upper clamp half  3600  and lower clamp half  3602  to restrain the perimeter of diaphragm  104 . Depending on the tensioning method utilized, the upper and lower clamp halves may be downwardly displaced to a predetermined position, or may be displaced until a certain force is generated, or may be displaced until a certain resonance frequency is generated or until a certain deflection of diaphragm  104  per unit load is defined. 
     As upper clamp half  3600  moves downward, diaphragm  104  is lowered into contact with adhesive  406  positioned on planar mounting surface  414 . Upper clamp half  3600  continues to move downward stretching film  400  over frame  102  until the desired tension in diaphragm  104  is achieved. When the tensioning process is complete, radiation source  3302  is turned on to cure adhesive  406  and edge treat compound  3206 . After completion of the exposure to the radiation, radiation source  3302  is turned off and retracted. 
     Any number of bonding agents may be used to couple diaphragm  104  to frame  102 . In the preferred embodiment, an adhesive curable by exposure to light in the visible spectrum such as Loctite Corp. 3106 is used. However, adhesives curable by exposure to ultra-violet light or other types of radiation may also be used. Certain pressure sensitive compounds may also be used. Beneficially, pressure sensitive compounds do not require the use of light permeable diaphragms and fixturing that allows light to pass to the bonded perimeter. Heat curable adhesives may also be used. 
     Pallet  2402  next travels to a terminal insertion station  3400 . Terminal insertion station  3400  has a vibratory bowl feeder  3402  that works in conjunction with a terminal crimper  3404  and a terminal insertion tool  3406 . Vibratory bowl feeder  3402  orients a large quantity of conductor assemblies  230  and individually feeds terminal assemblies one at a time to an escapement positioned below vibratory bowl feeder  3402 . As pallet  2402  enters terminal insertion station  3400 , a pressure pad  3408  extends downwardly from terminal crimper  3404  to engage speaker  100  near first end  204  and second end  206  of conductor  106 . Terminal insertion tool  3406  obtains a single conductor assembly  230  from the escapement and installs it through apertures  214  and  216  of frame  102 . During the insertion operation, the terminals pierce diaphragm  104  at first end  204  and second end  206  to form an electrical connection thereto. Crimper  3404  crimps the two electrical terminals to diaphragm  104 . Additionally, crimper  3404  couples conductor assembly  230  by mechanically deforming fastener  226  at the same time the electrical terminals are crimped. Terminal insertion tool  3406  and crimper  3404  then retract. 
     Pallet  2402  next travels to a diaphragm trim station  3500 . Diaphragm trim station  3500  includes a cartesian arm  3502  equipped with a cutter  3504 . Once pallet  2402  arrives at diaphragm trim station  3500 , Cartesian arm  3502  lowers cutter  3504  into engagement with diaphragm  104  to trim excess film  400  from diaphragm  104 . The X axis motion for cutter  3504  is provided by track  2404 . Motion along the Y and Z axes is provided by Cartesian arm  3502 . 
     Pallet  2402  next travels to an unclamping station  2412 . At unclamping station  2412 , upper clamp half  3600  is removed and placed on protrusion  2500  of pallet  2402 . The excess film that was previously trimmed from diaphragm  104  is also removed and discarded. 
     Pallet  2402  next travels to a test station  2414 . At test station  2414 , speaker  100  is acoustically tested. During the acoustical test, the completed electro-dynamic loudspeaker  100  is excited using a predefined input. The actual acoustical output from each loudspeaker  100  is compared to a target output. The actual output and target output are compared to determine if the speaker meets quality standards previously defined. Tested loudspeaker  100  is removed from pallet  2402  and is sorted according to the results of the acoustical test. Pallet  2402  continues to travel along track  2404  and returns to frame loading station  2408  to begin the process once again. 
     While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that other embodiments and implementations are possible that are within the scope of this invention. Accordingly, the invention is not restricted except in light of the attached claims and their equivalents.

Technology Classification (CPC): 7