Abstract:
Various improvements and configurations for magnetic musical instrument pickups. Many of the embodiments discussed herein include printed circuit board (pcb) coils, but other embodiments may involve conventional wire wound coils. In some embodiments, the coils (pcb and/or wire wound) are encased in rigid encasement material (see DEFINITIONS section) to reduce microphony and make a quieter pickup. Also, the use of pcb coils allows for many and various new coil shapes and/or configurations because the footprint and stacking of pcb traces are relatively easy to control and/or change. Also disclosed are electromagnetic field interference reduction techniques and integration of multiple coils directly into a single pcb substrate and/or scratchpate. Also disclosed is the use of Hallbach biasing magnet arrays in connection with wire wound and/or pcb coils.

Description:
RELATED APPLICATION 
       [0001]    The present application claims priority to the following: (i) U.S. provisional patent application 61/497,097 filed on 15 Jun. 2011; (ii) U.S. provisional patent application 61/498,811 filed on 20 Jun. 2011; (iii) U.S. provisional patent application 61/501,023 filed on 24 Jun. 2011; (iv) U.S. provisional patent application 61/507,688 filed on 14 Jul. 2011; and (v) U.S. patent application Ser. No. 12/915,987 (the “First Generation Application”) filed 29 Oct. 2010; all of the foregoing document(s) are, in their respective entirety(ies), hereby incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to musical instrument pickups, more particularly to magnetic musical instrument pickups having coil pickups. 
         [0004]    2. Description of the Related Art 
         [0005]    Magnetic pickups for musically instruments conventionally include a wire coil which is formed by winding a self supporting wire around a support structure. These will be called wire wound pickups herein. The wire wound pickup will also generally include a permanent magnet and a set of pole pieces. The magnet provides the magnetic flux to magnetize a vibrating string. The pole pieces direct the magnetic field so that there will be a relatively strong magnetic field (that is, many magnetic flux lines) in the vibrating string, and especially in the part of the vibrating string in the vicinity of the coil. For example, the magnet may be located under the coil and the pole piece may extend upwards through the aperture in the center of the coil where it terminates just under a vibrating string of the stringed instrument. The vibration of the magnetized string induces current in the coil. This current forms a signal that is then amplified to make the sound of the stringed instrument. There are many types of wire wound magnetic musical instrument pickups, such as U.S. Pat. No. 2,896,491 (“Lover”) and US patent application 2011/0048215 (“215 Lace”). As a further example, US patent application 2007/0017355 (“355 Lace”) discloses a magnetic musical instrument pickup with hum rejecting shields. 
         [0006]    Printed circuit board (PCB) coils (see DEFINITIONS section) are known for various applications. For example, the Tyndall National Institute Brochure entitled “PCB Fluxgate Magnetic Field Sensors” (at techtransfer.ucc.ie/industry/documents/FluxgateleafletlIV13 — 000.pdf as of 16 May 2012) discloses the use of PCB coils in magnetic field sensors for low intensity magnetic fields, like the Earth&#39;s magnetic field. 
         [0007]    Other published documents which may contain useful background information, and which may be prior art include the following: (i) US patent application 2006/0174755 (“Ito”); (ii) US patent application 2009/0085706 (“Baarman”); (iii) US patent application 2012/00369893 (“Ambrosino”); (iv) US patent application 2005/0060732 (“Kang”); (v) US patent application 2011/0034069 (“Jacob”); (vi) US patent application 2003/0169039 (“Kang”); (vii) US patent application 2005/0024750 (“Kato”); (viii) US patent application 2006/0077785 (“Kuo”); (ix) http://www2.electronicproducts.com/A_component_that_marks_the_end_of_hand_wou nd_coils_in_datacom-article-poyrc07_jan2012-html.aspx, as of Jan. 1, 2012, pages 1-2 (“electronicproducts.com”); (x) TYCO ELECTRONICS CORPORATION, White Paper, Improving Data Communication Products with Planar Magnetics, 2011, http://www.te.com/planarmag, pages 1-6 (“Tyco”); (xi) U.S. Pat. No. 7,601,908 (“Ambrosino”); and/or (xii) US patent application 2004/0044382 (“Ibrahim”). 
         [0008]    Description Of the Related Art Section Disclaimer: To the extent that specific publications are discussed above in this Description of the Related Art Section, these discussions should not be taken as an admission that the discussed publications (for example, published patents) are prior art for patent law purposes. For example, some or all of the discussed publications may not be sufficiently early in time, may not reflect subject matter developed early enough in time and/or may not be sufficiently enabling so as to amount to prior art for patent law purposes. To the extent that specific publications are discussed above in this Description of the Related Art Section, they are all hereby incorporated by reference into this document in their respective entirety(ies). 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    As described in the First Generation Application, printed circuit board (PCB) style coils can be used in magnetic pickups for musical instruments, such as six string electric guitars. As described in the First Generation Application, these PCB coils may be used to replace (or perhaps supplement) traditional wire wound coils. The present application builds on this previous work in various ways. 
         [0010]    One aspect of the present invention is a magnetic instrument pickup having a coil (a PCB coil or a wire wound coil) that is encased in a relatively rigid material, such as PCB material (see DEFINITIONS section). By encasing the coil in a rigid material, it has been found that the relative motion of the windings of the coil relative to each other and/or the instrument body (this is called “microphony”) can be greatly reduced. This generally results in a much quieter electrical signal from the coil generated in response to the vibration of the magnetized string. The reduction in microphony can lead to a flatter response and a more aesthetically pleasing instrument sound. 
         [0011]    Other aspects of the present invention involve many and various new coil shapes and/or configurations that become possible because the footprint and stacking of pcb traces are relatively easy to control and/or change. Other aspects of the present invention involve electromagnetic field interference reduction techniques. Another aspect of the present invention involves integration of multiple coils directly into a single pcb substrate and/or scratchpate. Another aspect of the present invention involves the use of Hallbach biasing magnet arrays. 
         [0012]    According to an aspect of the present invention, a magnetic musical instrument pickup is provided for use with a musical instrument. The pickup includes: a coil structure (including multiple loops made of a conductor path); and encasement material. The encasement material is a rigid encasement material (see DEFINITIONS section). The coil structure is at least substantially encased in the encasement material so that the loops of the coil are substantially rigidly constrained from relative movement with respect to each other. 
         [0013]    According to another aspect of the present invention, a musical instrument includes: a musical instrument frame; a first magnetizable string; a pickup frame hardware set; a coil structure comprising multiple loops made of a conductor path; and multiple permanent magnets. Each permanent magnet defines a north pole, a south pole and a magnet axis running along a north-to-south pole direction. The first magnetizable string is mechanically connected to the musical instrument frame such that it is free to vibrate. The musical instrument frame and the pickup frame hardware set are mechanically connected to each other. The pickup frame hardware set mechanically connects the coil structure and the plurality of permanent magnets to each other. The permanent magnets are arranged in the pattern of a Hallbach array. The magnets are located and oriented so that the Hallbach array arrangement of the permanent magnets increases magnetic flux density in the vicinity of a portion of the first magnetizable string. 
         [0014]    According to another aspect of the present invention, a musical instrument includes: a musical instrument frame; a first magnetizable string; a pickup frame hardware set; a first coil structure (including multiple loops made of a conductor path that defines a first coil axis); and a second coil structure (including multiple loops made of a conductor path that defines a second coil axis). The first magnetizable string is mechanically connected to the musical instrument frame such that it is free to vibrate. The musical instrument frame and the pickup frame hardware set are mechanically connected to each other. The first coil structure is a pcb coil with its multiple loops taking the form of traces and vias. The second coil structure is a pcb coil with its multiple loops taking the form of traces and vias. The pickup frame hardware set includes encasement material in the form of pcb material. The first coil structure is at least substantially encased in the encasement material so that the multiple loops of the coil are substantially rigidly constrained from relative movement with respect to each other. The second coil structure is at least substantially encased in the encasement material so that the multiple loops of the coil are substantially rigidly constrained from relative movement with respect to each other. The first and second coil structures are located in a side-by-side arrangement with the first and second coil axes being at least substantially parallel to each other. A winding direction of the first coil structure is opposite to a winding direction of the second coil structure. 
         [0015]    According to another aspect of present invention, a magnetic musical instrument pickup includes: a piece of encasement material (which is made of pcb material formed and arranged as a plurality of layers in a laminate structure); a first pcb coil structure (including a conductor path that includes a plurality of loops that define a first pcb coil axis); and a second pcb coil structure (including a conductor path that includes a plurality of loops that define a second pcb coil axis). The pickup is a laminate structure including multiple layers, with each layer including a layer of encasement material, one loop of the first pcb coil structure and one loop of the second pcb coil structure. 
         [0016]    According to another aspect of the present invention, a magnetic musical instrument pickup includes: a printed circuit board (made of pcb material; a first pcb coil structure; and a first magnetic member (including a first permanent magnet). The first pcb coil structure is encased in the pcb material. The printed circuit board has defined therein a first recess. The first recess is located at least substantially within the interior volume of the first coil structure. The first magnetic member is located at least partially in the first recess. The printed circuit board is sized and shaped as a scratchpate that can be mounted on a guitar type musical instrument that is designed to incorporate a scratchpate. 
         [0017]    According to another aspect of the present invention, a musical instrument includes: a musical instrument frame; a set of magnetizable strings (including a first string and a second string); a first pcb coil structure; a second pcb coil structure; a set of permanent magnet(s) comprising at least one permanent magnet; and a pickup frame hardware set. The strings of the set of magnetizable strings are each mechanically connected to the musical instrument frame such that each string of the set of strings is free to vibrate. The musical instrument frame and the pickup frame hardware set are mechanically connected to each other. The pickup frame hardware set mechanically connects the first and second pcb coil structures and the set of permanent magnet(s) to the musical instrument frame. The first pcb coil structure is located: (i) in close proximity to the first string; but (ii) not located in close proximity to any of the other strings of the set of magnetizable strings. The second pcb coil structure is located: (i) in close proximity to the second string; but (ii) not located in close proximity to any of the other strings of the set of magnetizable strings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which: 
           [0019]      FIG. 1  is a schematic view of a first embodiment of a musical instrument according to the present invention; 
           [0020]      FIG. 2  is a perspective view of a first embodiment of a pickup used in the first embodiment musical instrument; 
           [0021]      FIG. 3  is an orthographic top view of a second embodiment of pickup according to the present invention; 
           [0022]      FIG. 4  is an orthographic front view of the second embodiment pickup; 
           [0023]      FIG. 5  is an orthographic top view of a third embodiment of pickup according to the present invention; 
           [0024]      FIG. 6  is an orthographic front view of the third embodiment pickup; 
           [0025]      FIG. 7  is a schematic of one layer of a pcb coil structure according to an integrated humbucker aspect of the present invention; 
           [0026]      FIG. 8  is a schematic of one layer of a pcb coil structure according to an integrated humbucker aspect of the present invention; 
           [0027]      FIG. 9  is a transverse cross-section of a portion of a pcb coil structure for use in pickups of the present invention; 
           [0028]      FIG. 10  is an orthographic top view of a portion of a pcb coil trace for use in pickups of the present invention; 
           [0029]      FIG. 11  is an orthographic top view of a fourth embodiment of a pickup according to the present invention; 
           [0030]      FIG. 12  is a perspective, partially cut-away view of the fourth embodiment pickup; 
           [0031]      FIG. 13  is a perspective, partially cut away view of a fifth embodiment of a pickup according to the present invention; 
           [0032]      FIG. 14  is an orthographic top view of a sixth embodiment of a pickup according to the present invention; 
           [0033]      FIG. 15  is an orthographic top view of a seventh embodiment of a pickup according to the present invention; 
           [0034]      FIG. 16  is a perspective, partially cut-away view of a portion of an eighth embodiment of a pickup according to the present invention; 
           [0035]      FIG. 17  is a schematic view of a ninth embodiment of a pickup according to the present invention; 
           [0036]      FIG. 18  is a perspective, partially cut away view of a tenth embodiment of a pickup according to the present invention; 
           [0037]      FIG. 19  is a perspective, partially cut-away view of an eleventh embodiment of a pickup according to the present invention; 
           [0038]      FIG. 20  is a schematic view of a second embodiment of a musical instrument according to the present invention; 
           [0039]      FIG. 21  is a schematic view of a third embodiment of a musical instrument according to the present invention; and 
           [0040]      FIG. 22  is an orthographic front cross-sectional (some cross-hatching omitted for clarity of illustration) view of a pcb coil for use in pickups according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0041]      FIGS. 1 and 2  show musical instrument  100  including pickup assemblies  101   a ,  101   b;  instrument body  110 ; and vibrating magnetizable string  112 . Each magnetic instrument pickup assembly  101   a  and  101   b  respectively includes: substrate material  102 ; permanent magnets  104 ; and coil  106 . The substrate material is PCB material (see DEFINITIONS section). The coil is a PCB coil (see DEFINITIONS section). Because the coils are encased in a “rigid encasement material” (for example, a polymer based material, such as epoxy resin of the type typically used in laminated pcb manufacture), the pickups are quiet and have a flat response, due to a reduction and/or elimination of microphony in the coil. 
         [0042]    In embodiment  100 , the magnets are placed on top of the substrate and its embedded coil. Alternatively or additionally, the magnets could be placed on the underside of the substrate/coil board. Magnets on top of the substrate (as shown in  FIG. 1 ) have the advantage of being relatively close to the string, and therefore magnetizing the string to a higher flux density. On the other hand, magnets under the substrate have the advantage of being out of the way, in both the sense that they cannot be seen as easily and the sense that they will not be accidentally touched as easily. 
         [0043]    As shown in  FIG. 1 , the assemblies  101   a  and  101   b  are formed as separate piece parts, and then mounted to the instrument body so that the coils  106   a  and  106   b  are wound in mutually opposing winding directions. This is sometimes referred to as a humbucker arrangement, and it is believed to be novel to place pcb-coil-based magnetic instrument pickups in a humbucker arrangement. The primary advantage of the humbucker arrangement is that external fields (for example, from fluorescent light fixtures) are effectively cancelled by the fact that the opposing winding direction effectively “cancels out” interference caused by external electromagnetic fields due to the opposing winding direction and that the signals from the coils are combined by other circuitry (not shown) before being output as an electrical audio signal. 
         [0044]    As a preferred way of making pickups  101 , two separated pcb coils (one clockwise, the other one counterclockwise) are printed simultaneously in a one piece coil stackup and are cut out from the laminated pcb as one piece. The coils are connected at the ends of the winding structure (similar to what one would do using two separately wound solenoids in a conventional wire wound humbucker). 
         [0045]      FIGS. 3 and 4  show magnetic musical instrument pickup  200  including: substrate  202 ; magnetic members  204 ; and single coil  206  (shown in  FIG. 3  only). Substrate  202  has three holes  208  formed therein. These three holes accommodate magnetic members  204 . The magnet members may be magnets, pole pieces (that is, material that is magnetizable in any sense) or a combination of the two. As best shown in  FIG. 3 , there is a clearance gap between the edges of the square hole and the cylindrical magnetic member. Alternatively, the magnetic member could be encased (that is, permanently fixed within) the substrate material. As best shown in  FIG. 4 , the magnetic members extend both over and under the substrate, but other arrangements are possible. For example the magnetic members could be flush with the major surface of the substrate on one or both sides. As a further alternative, the substrate may extend beyond the magnetic member on one or both major surface sides. As a further alternative, the through holes  208  could be made as recesses for accommodating magnetic members that do not extend all of the way through the substrate. 
         [0046]    In embodiment  200 , the magnet members are preferably magnetized to define a polar axis that is at least substantially perpendicular to the major surfaces of the substrate encasing the pcb coil. This magnetic field orientation allows for further reduction of the overall height and it also provides a secure way to fix the magnets at a desired location within the pickup. 
         [0047]      FIGS. 5 and 6  show pickup  250  including substrate  252 ; magnetic members  254 ; and coil  256 . In this variation, a single hole  258  in substrate  252  accommodates multiple magnetic members. 
         [0048]      FIGS. 7 and 8  show a schematic for winding an integrated humbucker pcb coil according to the present invention.  FIG. 7  shows the trace winding pattern for a first layer  300  of the integrated humbucker coil and  FIG. 8  shows the trace winding pattern for the second layer of the integrated humbucker PCB coil. As a preferred way of making integrated humbucker  300 ,  302 , the clockwise and counterclockwise coils are printed and connected on each layer. It is not believed that this integrated winding pattern is used in conventional wire wound coils, and it may not be feasible there. 
         [0049]    With pcb coils, on the other hand, this integrated humbucker design is easy and relatively inexpensive to achieve. Also, because both opposing winding direction coils (marked CW and CCW, respectively in  FIGS. 7 and 8 ) are encased within the same substrate, these coils will not only exhibit the reduced microphony and quietness that characterizes pcb-coil-based magnetic instrument pickups in general, but it will also assure the correct positioning of the coils relative to each other, and that the two opposing winding direction coils will not move relative to each other. Of course, fewer piece parts also will tend to reduce inventory and assembly costs, and reduce the possibility of assembly errors in achieving the humbucker arrangement during instrument manufacture or repair. For these reasons, this integrated humbucker design may have advantages even over the pcb-coil-based humbucker arrangement described above in connection with embodiment  100 . 
         [0050]      FIG. 20  shows instrument  950  including: wire wound pickup coil  952 ; pcb pickup coil  945  Hallbach magnet array  956 ; and vibrating magnetizable strings  958 . In embodiments of the invention that include Hallbach array style biasing magnets, magnets  956  are arranged so that field output is low on coil side (where magnetic flux is not particularly helpful), but high on the string side, as shown in  FIG. 20 . This Hallbach arrangement tends to increase flux density in the vicinity of the magnetizable strings and therefore magnetizes the strings to a greater degree. This, in turn, results in a strong audio electrical signal to be transduced in the pickup coil (traditional wire wound or pcb coil style). One potential advantage of using the pcb coil is that its low profile may leave more space (for example, space between the strings of an electric guitar and the guitar body&#39;s upper major surface) for the Hallbach array. 
         [0051]    Before moving long to some additional embodiments of magnetic musical instrument pickups according to the present invention, a brief discussion of some pcb coil pickup related terminology will be now presented with reference to  FIGS. 9 and 10 .  FIGS. 9 and 10  show pcb substrate  325  and trace  326 . The trace is a pcb-material-supported conductive path parallel to the major surfaces of the substrate in which it is encased and rigidly secured. Because of the way pcb&#39;s are manufactured, by lamination of trace-bearing layers formed with appropriate vias, the height H of the trace is quite thin, and also generally fairly uniform (or even constant) over the entire run of the trace. Traces (preferably copper) in a single laminated PCB substrate stack will often all have the same height, and this height is relatively small. Note that the height dimension H shown in  FIG. 9  is not drawn to scale. On the other hand, the width W of a trace can vary widely over the length L of the trace. This is shown in  FIG. 10  which has been drawn to shown a highly arbitrary trace pattern to demonstrate just how the width and “footprint shape” of the trace can vary along the trace&#39;s length. 
         [0052]    Furthermore, in a pcb laminated stack assembly according to the present invention, each loop (or set of concentric same-layer loops or portions of a loop or set of same height loops) will occupy its own layer. This means that each loop of the coil may have a very different footprint shape. As one example of this, a pcb coil may be made with wide traces toward the string side of the pcb, but with less wide traces toward the major surface side of the board facing away from the strings. It may also be possible to make a coil that has different quantities of loops at different layers, using conventional pcb traces and pcb vias. 
         [0053]      FIGS. 11 and 12  show a magnetic pickup assembly  400  including: scratch plate  402 ; first substrate  404 ; second substrate  406 ; first pcb coil  408 ; second pcb coil  410 ; third pcb coil  412 ; fourth pcb coil  414 ; pole pieces  416 ,  418 ,  420 ; and permanent magnet  422 . As is best seen in  FIG. 12 , the first and second substrates  404 ,  406  are partially embedded in the scratch plate member. The magnet magnetizes the pole pieces and, when the scratch plate is mounted in place on an electric guitar body, the pole pieces magnetize the vibrating strings. Preferably each pcb substrate sub-assembly respectively has the integrated double humbucker type winding, discussed above in connection with  FIGS. 7 and 8 . While this embodiment shows four coils total, the fact that the windings are so low in profile may allow designers to advantageously use even more windings, both in and/or on the scratch plate, and perhaps even on different parts of the electric guitar (such as the neck). 
         [0054]    As shown in  FIG. 12 , the pcb subassembly slightly protrudes from the upper major surface of the scratch plate, but other arrangements are possible. For example, the pcb could be flush with the scratch plate, or, it could be recessed below the upper major surface of the scratch plate. In embodiment  400 , the pcb sub-assemblies (including magnet  402 ) does not extend all of the way through the scratch plate, but this is also possible. By placing the PCB coils in, or partially within, the internal space of the scratch plate both guitar aesthetics and/or audio performance may be improved. 
         [0055]      FIG. 13  shows pickup  500 , including: magnet  522 ; three pole pieces  516   a,b,c;  three pcb coils  508   a,b,c  and rigid polymer-based substrate  504 . In embodiment  600 , there is a dedicated winding for each string on the instrument. For example, if the instrument is a six string electric guitar then there would be six windings (a hex coil pickup). This embodiment also has a dedicated pole piece for each winding, and each pole piece is encased in the rigid substrate, along with the coils. Because pcb coils can be made so small, and because they can easily be made with an arbitrary footprint shape, the multiple coil pickup of  FIG. 13  is much easier to make than it would be in the context of a conventional wire wound pickup. This is another advantage of pcb coil pickups over conventional wire wound pickups, at least for some applications. 
         [0056]      FIG. 14  shows scratch plate pickup  600  including substrate-material scratch plate member  604 ; and magnetic member  616 . Encased within scratch plate member  604  is coil structure  608 . Coil structure  608  includes looping traces  631 ,  632 ,  633  and  634 . Scratch plate member  604  also has through hole (or recess)  605 , which is sized and shaped to accommodate the large magnetic member that resides under a relatively large portion of the strings (not shown) of the electric guitar. Coil  608  has a relatively large footprint shape. 
         [0057]    Coil  608  also has traces  631 ,  632 ,  633 ,  644  with various footprint shapes that have been selected to be arbitrary to show some of the flexibility in loop conductive path profile that the pcb coils of the present invention allow the guitar pickup designer. It is noted that a pickup coil (pcb or wire wound), with its closely spaced windings, will be characterized by a capacitance and an inductance. This means that the coil acts as a tank circuit and will also be characterized by a resonant frequency. This resonant frequency of the pickup is already well-understood in the art of conventional wire wound pickups. It is known that the location of the resonant frequency, within the audio frequency spectrum, can have an impact on the way the musical instrument sounds. This resonant frequency is often controlled by wire wound pickup designers to tailor and/or optimize the aesthetics of the musical instrument sound, the quality of the sound. However, the use of wire windings generally imposes constraints upon how much the resonant frequency can be “tweaked” in a given wire wound pickup design. On the other hand, the use of pcb coils according to the present invention allows the designer much greater flexibility in controlling the resonant frequency. For example, it generally becomes easier to raise the resonant frequency up out of the human hearing range, which may be a desired effect in a given application. Even is the resonant frequency is desired to be somewhere down in the human hearing range (as it is in the overwhelming majority of conventional wire wound pickups) this adjustment of the resonant frequency becomes easier to tweak and also easier to reliably mass manufacture with accuracy and precision with respect to the characteristic resonant frequency of the pickup. 
         [0058]    The design flexibility of pcb coils may also help in the manufacture of coils that act as sustainers and the like. When using the coil as a sustainer, it may be necessary to provide an AC signal to the coil, as is understood in the art of conventional wire wound coil pickups having a sustainer feature. 
         [0059]      FIG. 15  shows scratch plate assembly  700  including: scratch plate member  702 ; substrate material  704 ; pcb mounted electrical components  701 ; and pcb coils  708 . One thing shown by embodiment  700  is that electrical components can be mounted on (and/or in) the same printed circuit board as the one in which the coil(s) are encased and secured. These components may include amplifiers to amplify the electrical audio signals received from the coil(s), preferably through trace(s) and via(s) (not shown) built right into the pcb itself. The board mounted components may be placed on the outward facing (or upwards) side of the pcb and/or on the underside. Another feature of embodiment  700  is the arbitrary nature of the coil footprint shapes. This is shown to emphasize and illustrate the point that the use of pcb coils really opens up possibilities to get new sounds out of electric guitars and other musical instruments with vibrating strings. 
         [0060]      FIG. 16  shows pickup  800  including substrate material  804 , inner coil  808 b and outer coil  808   a . In this embodiment, the two coils may be mutually electrically isolated from each other, or not. They may be would in the same winding direction, or in opposite winding directions. In some variations, this novel two coil structure may help cancel electrical interference from external electromagnetic fields. The musical instrument may be structured to allow the instrument player to select which of the two coil(s) are used at any given time to help produce the aggregated electrical audio signal. 
         [0061]      FIG. 17  shows pickup  850  including pole pieces  816   a,b;  permanent magnets  822   a,b;  and pcb coil loops  858   a,b.  In embodiment  850 , the two “lobes” are in a figure eight configuration, including crossing point  859 . The scheme may be extended to include additional lobes and additional crossing points (which would herein still be referred to as a “figure eight configuration” even in cases where there are additional lobes and crossing points). This configuration is believed to be difficult and/or impossible in the context of conventional wire wound pickups, but is believed to be achievable with the pcb coils of the present invention. It is not yet known what impact this coil configuration might have on the audio performance of a musical instrument. 
         [0062]      FIG. 18  shows pickup  890 , including: magnet  892 ; substrate material  894 ; embedded shield member  893 ; and pcb coil  898 . The shield member is used to reduce magnetic and/or electromagnetic interference from affecting the signal transduced in the pcb coil. 
         [0063]      FIG. 19  shows pickup  900 , including first shield member  903 ; substrate material  904 ; second shield member  905 ; and pcb coil  908 . The first shield member may be similar to the shield member of embodiment  890 , discussed above. The second shield member is a mesh laminated onto the top surface of the pcb. Other types of shielding (now known or to be developed in the future), not necessarily involving a mesh structure shield, may also be helpful. This shield is designed to reduce electromagnetic interference in the manner of a Faraday cage. It is noted that any shielding between the pcb coil and the vibrating string should preferably not be a magnetic field shield because this would, of course, prevent the vibration of the string from being transduced into the electric audio signal in the coil. 
         [0064]      FIG. 21  shows instrument  980 , including: strings  981 ; and two pcb coils  982 . As shown by embodiment  980 , in arrangements with a dedicated pcb coil for each string, the coils may be elongated along the string length so that vibration from a relatively long portion of each string will be transduced into the audio electrical signal. 
         [0065]      FIG. 22  shows pcb pickup coil  1000 , including: laminate pcb encasement material  1002  (layers not separately demarcated for clarity of illustration purposes); loop traces  1004 , vias  1006 ; and pads  1008 . As shown in  FIG. 22 , the footprint of each loop is different in this embodiment. 
         [0066]    PCB coil pickups of the present invention may be easily mounted over existing pickup openings in solid body guitars, or over existing sound openings in acoustic guitars. In this way, the pcb coils of the present invention may be used in novel types of retrofittings. As mentioned above, a user switch or dial or other interface device may be used to select which pcb coil(s) are active at any given time in a musical instrument having multiple pcb coils. 
         [0067]    In another variation, thin laminated boards (˜1 mil thickness) are used so that more windings can be brought closer to the strings. This will increase the output signal or allows one to get the same signal level with a lower number of windings compared to standard wire wound pickups (wire wound pickups typically use 42 gauge wire which is about 2.8 mil thick). 
       Definitions  
       [0068]    Any and all published documents mentioned herein shall be considered to be incorporated by reference, in their respective entireties. The following definitions are provided for claim construction purposes: 
         [0069]    Present invention: means “at least some embodiments of the present invention,” and the use of the term “present invention” in connection with some feature described herein shall not mean that all claimed embodiments (see DEFINITIONS section) include the referenced feature(s). 
         [0070]    Embodiment: a machine, manufacture, system, method, process and/or composition that may (not must) be within the scope of a present or future patent claim of this patent document; often, an “embodiment” will be within the scope of at least some of the originally filed claims and will also end up being within the scope of at least some of the claims as issued (after the claims have been developed through the process of patent prosecution), but this is not necessarily always the case; for example, an “embodiment” might be covered by neither the originally filed claims, nor the claims as issued, despite the description of the “embodiment” as an “embodiment.” 
         [0071]    First, second, third, etc. (“ordinals”): Unless otherwise noted, ordinals only serve to distinguish or identify (e.g., various members of a group); the mere use of ordinals shall not be taken to necessarily imply order (for example, time order, space order). 
         [0072]    Electrically Connected: means either directly electrically connected, or indirectly electrically connected, such that intervening elements are present; in an indirect electrical connection, the intervening elements may include inductors and/or transformers. 
         [0073]    Mechanically connected: Includes both direct mechanical connections, and indirect mechanical connections made through intermediate components; includes rigid mechanical connections as well as mechanical connection that allows for relative motion between the mechanically connected components; includes, but is not limited, to welded connections, solder connections, connections by fasteners (for example, nails, bolts, screws, nuts, hook-and-loop fasteners, knots, rivets, quick-release connections, latches and/or magnetic connections), force fit connections, friction fit connections, connections secured by engagement caused by gravitational forces, pivoting or rotatable connections, and/or slidable mechanical connections. 
         [0074]    rigid encasement material: any substantially non-electrically conductive material that is sufficiently rigid so that when it encases a magnetic musical instrument pickup, then relative movement of the loops of the coil of the pickup will be substantially reduced or eliminated; rigid encasement materials may include: ceramic-based material, and polymer-based material (see DEFINITIONS section). 
         [0075]    polymer-based material: any relatively rigid (when used to encase coils) material that is made up substantially of polymer material; polymer-based materials include at least some epoxy resins and at least some plastics; “polymer-based materials” would not include wax due to its relative lack of rigidity even when used in encasements for coils. 
         [0076]    pcb material: any rigid, electrically insulative polymer-based material (see DEFINITION) that is suitable for making printed circuit boards by lamination operations; one example of pcb material is laminated and hardened epoxy resin of the type used to make currently conventional rigid printed circuit boards. 
         [0077]    pcb coil: a coil made of current path member(s) that are not self supporting and must be laminated into a pcb in order to maintain their shape and/or structural integrity.