Noise reduction device and musical instrument

Abstract

To provide a noise reduction device that can achieve noise cancellation according to products.SOLUTION: A noise reduction device (dummy coil 1) is attached to a musical instrument (electric guitar 7) having an electromagnetic pickup 72 that detects magnetic field changes based on vibrations of a string 71. The noise reduction device comprises: a coil 20; a core material 4 made of a soft magnetic material; and an adjustment member 3 for variable adjustment of a relative position of the coil 20 and the core material 4, where the core material 4 is not magnetized.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to noise reduction techniques used in musical instruments that have electromagnetic pickups. [Background technology]

[0002] In electric guitars, electromagnetic pickups are used to convert string vibrations into electrical signals. There are two types of electromagnetic pickups: single-coil pickups and humbuckers (humbucking pickups). The output signal of a single-coil pickup contains hum, which is environmental magnetic field noise. A humbucker is made up of two coils wound in opposite directions, and can cancel hum. However, humbuckers have a different tone than single coils. Therefore, there is a demand for a pickup that can cancel hum while maintaining the tone of a single pickup coil.

[0003] In the following Patent Document 1, a low impedance dummy coil is connected to a single coil pickup. This is an attempt to cancel hum noise while maintaining the tone of the single coil pickup. In Patent Document 1, the size of the dummy coil is increased to ensure induced electromotive force for canceling hum. As a result, the size of the dummy coil is large, which places great restrictions on mounting it on a guitar. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 7,259,318 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 proposes a mechanism for canceling noise using a dummy coil. However, the hum noise generated in electric guitars varies between products due to manufacturing variations in the components that make them up.

[0006] An object of the present invention is to provide a noise reduction device capable of achieving optimal noise cancellation depending on the product. [Means for solving the problem]

[0007] A noise reduction device according to one embodiment of the present invention is a noise reduction device that is attached to a musical instrument having an electromagnetic pickup that detects magnetic field changes due to string vibrations, and comprises a coil, a core material made of a soft magnetic material, and an adjustment member that variably adjusts the relative position of the coil and the core material, wherein the core material is not magnetized.

[0008] Another aspect of the present invention provides a musical instrument that includes an electromagnetic pickup that detects magnetic field changes due to string vibrations, and a noise reduction device, the noise reduction device having a coil wound in the opposite direction to the electromagnetic pickup coil, a core material made of a soft magnetic material, and an adjustment member that variably adjusts the relative position of the coil and the core material, wherein the core material is not magnetized.

[0009] Another aspect of the present invention provides a musical instrument that includes an electromagnetic pickup that detects magnetic field changes due to string vibrations, and a noise reduction device, the noise reduction device having a coil wound in the opposite direction to the electromagnetic pickup coil, a core material made of a soft magnetic material, and an adjustment member that variably adjusts the relative position of the coil and the core material, and the noise reduction device does not detect magnetic field changes due to string vibrations at a perceptible level.

[0010] Another aspect of the present invention provides a musical instrument comprising an electromagnetic pickup that detects magnetic field changes due to string vibration, and a noise reduction device, the noise reduction device having a coil wound in the opposite direction to the electromagnetic pickup coil, a core material made of a soft magnetic material, and an adjustment member that variably adjusts the relative position of the coil and the core material, the noise reduction device being attached to the musical instrument in a second region different from a first region in which the electromagnetic pickup is attached, and the second region includes an area that is not affected by magnetic field changes due to string vibration. Effect of the Invention

[0011] According to the present invention, it is possible to provide a noise reduction device capable of achieving optimal noise cancellation depending on the product. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a perspective view of a dummy coil according to the embodiment. [Diagram 2] FIG. 1 is a block diagram showing the configuration of an electric guitar. [Diagram 3] FIG. 4 is a perspective view showing a bobbin of a dummy coil. [Figure 4] FIG. 4 is a perspective view showing an adjustment member inserted into the bobbin. [Diagram 5] FIG. 13 is a perspective view showing a core material inserted into the adjustment member. [Figure 6] 11A to 11C are diagrams showing a method for adjusting the insertion length of the adjustment member. [Figure 7] 11A and 11B are diagrams illustrating another example of the appearance of the dummy coil. [Figure 8] 11A to 11C are diagrams showing a method for adjusting the insertion length of the adjustment member. [Figure 9] 1 is a diagram showing the front side of the body of an electric guitar, illustrating the mounting positions of dummy coils. [Figure 10] 1 is a diagram showing the rear side of the body of an electric guitar, illustrating the mounting positions of dummy coils. [Figure 11] FIG. 13 is a perspective view of a dummy coil according to a modified example. [Figure 12] FIG. 13 is a perspective view of a dummy coil according to a modified example. [Figure 13] FIG. 13 is a diagram showing a dummy coil formed by connecting three coil sets. [Figure 14] FIG. 13 is a diagram showing a dummy coil formed by connecting three coil sets. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A noise reduction device and a musical instrument according to an embodiment of the present invention will now be described with reference to the accompanying drawings.

[0014] {1. Dummy coil configuration} The configuration of a dummy coil 1, which is an embodiment of a noise reduction device according to the present invention, will be described. FIG. 1 is a perspective view of the dummy coil 1 according to this embodiment. As shown in the figure, the dummy coil 1 is configured to include a bobbin 2, a coil 20 wound around the bobbin 2, an adjustment member 3, and a core material 4. Although the dummy coil 1 does not have a clearly defined up-down direction, for convenience, the up-down direction in FIG. 1 will be described as the up-down direction of the dummy coil 1. In the following description, the symbol U in the drawings will be described as the up-down direction of the dummy coil 1, and the symbol D will be described as the down-down direction of the dummy coil 1. Therefore, in FIG. 1 and the like, the up-down direction of the dummy coil 1 corresponds to the axial direction of the dummy coil 1.

[0015] In this embodiment, the dummy coil 1 is attached to an electric guitar 7 as an example. FIG. 2 is a block diagram showing the configuration of the electric guitar 7. An electromagnetic pickup 72 that detects magnetic field changes based on the vibration of a string 71 is attached to the electric guitar 7. The electromagnetic pickup 72 is a single coil pickup. The dummy coil 1 is connected to the electromagnetic pickup 72 to cancel hum noise output from the electromagnetic pickup 72. The electromagnetic pickup 72 and the dummy coil 1 are connected in series. In order to cancel hum noise, the dummy coil 1 and the electromagnetic pickup 72 are configured so that the winding directions of the coils are opposite to each other and the direction of the induced electromotive force is opposite to each other. By connecting the dummy coil 1 and the electromagnetic pickup 72, which have opposite coil winding directions, in series, a signal obtained by subtracting the output signal of the dummy coil 1 from the output signal of the electromagnetic pickup 72 can be obtained. At this time, the output signals of the dummy coil 1 and the electromagnetic pickup 72 contain signals based on the same noise. Therefore, by subtracting the output signal of the dummy coil 1 from the output signal of the electromagnetic pickup 72, the noise contained in the output signal of the electromagnetic pickup 72 can be canceled.

[0016] 3 is a perspective view showing the bobbin 2 of the dummy coil 1. The bobbin 2 has a cylindrical portion 21 having a substantially cylindrical shape extending in the vertical direction. The bobbin 2 has a disk portion 22U located at the upper end of the cylindrical portion 21 and a disk portion 22D located at the lower end. In this embodiment, the cylindrical portion 21 and the disk portions 22U and 22D are integrally molded from resin. The coil 20 is wound around the outer periphery of the cylindrical portion 21 as shown in FIG. 1. As described above, the coil 20 wound around the cylindrical portion 21 is connected to the coil of the electromagnetic pickup 72.

[0017] A cylindrical space 23 is formed in the center of the cylindrical portion 21. The space 23 is a space into which the adjustment member 3 is inserted. A screw groove 21a is formed in the inner diameter portion of the cylindrical portion 21.

[0018] FIG. 4 is a perspective view showing the adjustment member 3. The adjustment member 3 is a member for variably adjusting the relative position between the coil 20 and the core material 4. The adjustment member 3 is a cylindrical member. In this embodiment, the adjustment member 3 is made of resin. The adjustment member 3 is inserted into the space 23 of the bobbin 2. Three holes 31S are formed in the upper surface 31 of the adjustment member 3. Each of the holes 31S is a cylindrical hole. In this embodiment, the three holes 31S have the same diameter and depth. The core material 4 is inserted into the three holes 31S.

[0019] A screw groove 32a is formed on the outer periphery of the cylindrical portion 32 of the adjustment member 3. The adjustment member 3 is inserted from above the bobbin 2 while aligning it with the space 23 of the bobbin 2, and the screw groove 21a and the screw groove 32a are screwed together, thereby making it possible to adjust the insertion length (insertion depth) of the adjustment member 3 into the space 23. Fig. 1 shows a state in which the adjustment member 3 is completely inserted into the space 23.

[0020] FIG. 5 is a perspective view showing the core material 4. The core material 4 is inserted into the hole 31S of the adjustment member 3. The core material 4 is inserted in the axial direction of the dummy coil 1. As described above, the three holes 31S formed in the adjustment member 3 have the same shape. Therefore, in this embodiment, the three core materials 4 have the same shape. In this embodiment, the core material 4 is made of a soft magnetic material. Also, in this embodiment, the core material 4 is not magnetized. Since the core material 4 is not magnetized, the dummy coil 1 does not pick up string vibrations and can only pick up noise. For example, ferrite can be used as the core material 4. The dummy coil 1 of this embodiment is designed to ensure the necessary induced electromotive force by inserting the core material 4 (core) even when it is small and has a small number of coil turns.

[0021] In this embodiment, the number of holes 31S formed in the adjustment member 3 is three, but this number is not particularly limited. The number of holes 31S may be one or two, or may be four or more. The number of holes 31S may be determined according to the number of core materials 4 to be inserted. In this embodiment, the three holes 31S have the same cylindrical shape, but the shape is not limited to a cylindrical shape, and the shapes of the holes 31S may be different. The shape of the core materials 4 to be inserted may be determined accordingly.

[0022] {2. Adjustment of adjustment parts} FIG. 6 is a diagram showing a method for adjusting the insertion position of the adjustment member 3 relative to the bobbin 2. As shown in the top diagram of FIG. 6, the adjustment member 3 is inserted into the space 23 of the bobbin 2 from above the bobbin 2. The top diagram shows a state in which about 1 / 3 of the vertical length of the adjustment member 3 is inserted into the space 23. The second diagram from the top shows a state in which about 2 / 3 of the vertical length of the adjustment member 3 is inserted into the space 23. The bottom diagram shows a state in which the entire adjustment member 3 is inserted into the space 23. Such an insertion length of the adjustment member 3 can be adjusted by screwing the adjustment member 3 into the bobbin 2.

[0023] In this way, by adjusting the insertion length (insertion depth) of the adjustment member 3 into the bobbin 2, the relative position of the adjustment member 3 with respect to the dummy coil 1 in the axial direction of the dummy coil 1 is adjusted. This adjusts the core insertion length in the dummy coil 1. In other words, by adjusting the insertion length of the adjustment member 3 into the bobbin 2, the insertion length of the core material 4 in the axial direction of the dummy coil 1 is adjusted. By adjusting the axial insertion length of the core material 4 in the dummy coil 1, the apparent permeability of the dummy coil 1 changes. In this way, since the induced electromotive force is proportional to the permeability, by adjusting the insertion length of the adjustment member 3 to change the apparent permeability of the dummy coil 1, the dummy coil 1 of this embodiment can adjust the magnitude of the induced electromotive force.

[0024] The dummy coil 1 of this embodiment can adjust the insertion length of the adjustment member 3 according to the electric guitar 7 to which it is attached, and adjust the induced electromotive force of the dummy coil 1. This makes it possible to adjust the induced electromotive force of the dummy coil 1 according to the electromagnetic pickup 72 attached to the electric guitar 7, and cancel the hum noise of the electromagnetic pickup 72. The induced electromotive forces of the electromagnetic pickup 72 and the dummy coil 1 attached to the electric guitar 7 vary between products, but in this embodiment, the induced electromotive force of the dummy coil 1 can be adjusted to effectively cancel the hum noise of the electromagnetic pickup 72. This makes it possible to cancel the hum noise while maintaining the tone of the electromagnetic pickup 72, which is a single coil pickup.

[0025] {3. Appearance of the dummy coil} The dummy coil 1 shown in FIG. 1 has an external appearance of a substantially cylindrical shape. However, the external shape of the dummy coil 1 is not limited to this. For example, as shown in FIG. 7, it may have a horizontally elongated shape. The dummy coil 1A shown in FIG. 7 has a shape similar to a single pickup. The symbol U in the drawing indicates the upward direction of the dummy coil 1A, and the symbol D indicates the downward direction of the dummy coil 1A. The symbol L in the drawing indicates the leftward direction of the dummy coil 1A, and the symbol R indicates the rightward direction of the dummy coil 1A. In FIG. 7, the vertical direction of the dummy coil 1A corresponds to the axial direction of the dummy coil 1A. The structure of the dummy coil 1A is the same as the structure of the dummy coil 1 shown in FIG. 3 to FIG. 5. The dummy coil 1A includes a bobbin 2 and a coil 20 wound around the bobbin 2. An adjustment member 3 capable of variably adjusting the insertion length is inserted into the bobbin 2. A core material 4 is inserted into the adjustment member 3.

[0026] The bobbin 2 and the adjustment member 3 also have an appearance similar to that of a single pickup, which is elongated horizontally, similar to the appearance of the dummy coil 1A. The dummy coil 1A differs from the dummy coil 1 shown in FIG. 1 etc. in that six core materials 4 are inserted into the adjustment member 3. The core materials 4 are also arranged in a substantially linear manner in the adjustment member 3. However, the number of core materials 4 held by the adjustment member 3 is not particularly limited.

[0027] A dial 5 is provided on the upper part of the adjustment member 3 for adjusting the insertion length of the adjustment member 3 relative to the bobbin 2. The insertion length of the adjustment member 3 relative to the bobbin 2 is adjusted by operating the dial 5. For example, a shaft with a screw groove is connected to the dial 5, and the adjustment member 3 is formed with a screw groove that screws into the screw groove of the dial 5. By rotating the dial 5, the adjustment member 3, which holds the core material 4, moves up and down.

[0028] FIG. 8 is a diagram showing a method for adjusting the insertion length of the adjustment member 3 relative to the bobbin 2. By operating the dial 5, the insertion position of the adjustment member 3 moves vertically relative to the bobbin 2. By adjusting the insertion length (insertion depth) of the adjustment member 3 relative to the bobbin 2, the relative position of the adjustment member 3 relative to the dummy coil 1A in the axial direction of the dummy coil 1A is adjusted. This adjusts the core insertion length in the dummy coil 1A. In other words, by adjusting the insertion length of the adjustment member 3 relative to the bobbin 2, the insertion length of the core material 4 in the axial direction of the dummy coil 1A is adjusted. This changes the magnetic permeability of the dummy coil 1A. In this way, by adjusting the insertion length of the adjustment member 3, the dummy coil 1A of this embodiment can change the apparent magnetic permeability and adjust the magnitude of the induced electromotive force.

[0029] {4. Dummy coil installation position} The following describes the mounting positions of the above-described dummy coils 1, 1A on the electric guitar 7. Figures 9 and 10 are diagrams showing examples of mounting positions of the dummy coils 1, 1A. Areas 75a to 75f shown in Figures 9 and 10 indicate the mounting positions of the dummy coils 1, 1A.

[0030] As shown in FIG. 9, three regions 75a, 75b, and 75c are illustrated as attachment positions of the dummy coils 1 and 1A on the front side 70F of the body 70 of the electric guitar 7. Also, as shown in FIG. 10, three regions 75d, 75e, and 75f are illustrated as attachment positions of the dummy coils 1 and 1A on the back side 70B of the body 70 of the electric guitar 7. The regions 75a to 75f are regions that do not detect magnetic field changes caused by the vibration of the string 71 at a perceptible level. In other words, the regions 75a to 75f are regions that are not affected by magnetic field changes caused by the vibration of the string 71. Therefore, the regions 75a to 75f are regions excluding the region directly under the string 71 and the region around it. The regions 75a to 75f illustrated in FIG. 9 and FIG. 10 indicate attachment positions of the dummy coils 1 and 1A that are connected to the electromagnetic pickup 72 (single coil pickup) that is the front pickup. Similarly, when connecting the dummy coils 1, 1A to the center pickup and rear pickup, the dummy coils 1, 1A can be attached to areas such as areas 75a to 75f. The attachment position of the dummy coil 1 is preferably as close to the pickup as possible, as long as the magnetic field change caused by the string vibration is not detected at a perceptible level.

[0031] The area where the electromagnetic pickup 72 is attached is an example of the first area according to the present invention, and the areas 75a, 75b, 75c, 75d, 75e, and 75f are examples of the second area according to the present invention. The first area and the second area are areas that receive a common environmental magnetic field noise (e.g., hum noise). In other words, the electromagnetic pickup 72 and the dummy coils 1 and 1A are connected in series and the coil winding directions are opposite to each other, so that the environmental noise can be cancelled. In Figs. 9 and 10, the case where the dummy coils 1 and 1A are attached to the front or back surface of the body 70 has been described as an example, but the dummy coils 1 and 1A may also be attached to the side surface of the body 70.

[0032] {5. Variation 1} Next, a first modified example of the present invention will be described. FIG. 11 and FIG. 12 are diagrams showing the appearance of a dummy coil 1B according to the first modified example. Although the up-down and left-right directions of the dummy coil 1B are not clearly defined, in FIG. 11 and FIG. 12, the symbol U in the drawings will be described as the up-down direction of the dummy coil 1B, and the symbol D as the down-down direction of the dummy coil 1B. Also, the symbol L in the drawings will be described as the left-down direction of the dummy coil 1B, and the symbol R as the right-down direction of the dummy coil 1B. Therefore, in FIG. 11 and the like, the up-down direction of the dummy coil 1B corresponds to the axial direction of the dummy coil 1B. As shown in FIG. 11, the dummy coil 1B includes a bobbin 2, a coil 20 wound around the bobbin 2, and a core material 4 inserted into the space 23 of the bobbin 2, similar to the dummy coils 1 and 1A. In the example shown in the figure, four core materials 4 are inserted into the space 23, but the number of core materials 4 is not particularly limited. The number of core materials 4 may be three or less, or may be five or more.

[0033] In the above-described dummy coils 1, 1A, the insertion length of the core material 4 is adjusted in the axial direction of the dummy coils 1, 1A by adjusting the adjustment member 3. In the dummy coil 1B according to the first modification, the position of the core material 4 is adjusted in the left-right direction of the dummy coil 1B as shown in Fig. 12 by operating an adjustment member (not shown). In other words, the relative position of the core material 4 with respect to the dummy coil 1B is adjusted in the direction perpendicular to the coil axial direction. For example, the adjustment member has a configuration that allows it to slide left and right within the space 23 of the bobbin 2 while holding the core material 4.

[0034] In this way, in the dummy coil 1B according to the first modification, the position of the core material 4 is adjusted in a direction perpendicular to the coil axis direction. In general, inside a coil, the closer to the coil, the greater the inductance. In other words, the greater the apparent magnetic permeability. Therefore, the closer the position of the core material 4 is to the coil, the greater the induced electromotive force of the dummy coil 1B. The dummy coil 1B in the state shown in FIG. 12 has a greater induced electromotive force than the dummy coil 1B shown in FIG. 11. As a result, the dummy coil 1B according to the first modification can adjust the induced electromotive force of the dummy coil 1 according to the electromagnetic pickup 72 attached to the electric guitar 7, and can effectively cancel the hum noise of the electromagnetic pickup 72. The dummy coil 1B can also be attached to the body of the electric guitar 7 in the regions 75a to 75f shown in FIG. 9 and FIG. 10.

[0035] {6. Variation 2} Next, a second modified example of the present invention will be described. FIG. 13 is a diagram showing a dummy coil 1C according to the second modified example. The dummy coil 1C is configured by connecting three dummy coils 1Ca, 1Cb, and 1Cc in series. The dummy coils 1Ca, 1Cb, and 1Cc are examples of a coil set according to the present invention. The dummy coils 1Ca, 1Cb, and 1Cc each have the same configuration as the dummy coil 1 shown in FIG. 1. That is, the dummy coils 1Ca, 1Cb, and 1Cc can adjust their respective core insertion lengths by adjusting the adjustment member 3. However, the dummy coils 1Ca, 1Cb, and 1Cc have different diameters of the bottom surface of the bobbin 2. In the example shown in FIG. 13, the diameter of the bottom surface of the dummy coil 1Ca is larger than that of the dummy coils 1Cb and 1Cc. The diameters of the bottom surfaces of the dummy coils 1Cb and 1Cc are approximately the same.

[0036] The dummy coils 1Ca, 1Cb, 1Cc have different diameters at the bottom, and therefore the areas of the bottom of the coil 20 are different. As a result, the magnitude of the induced electromotive force in the dummy coils 1Ca, 1Cb, 1Cc is also different. If the electric guitar 7 has three electromagnetic pickups (first to third pickups), the hum noise of each of the three electromagnetic pickups is reduced by combining three coil sets as follows. However, the magnitude of the induced electromotive force in each electromagnetic pickup is 1st < 2nd < 3rd.

[0037] The dummy coil 1Ca is connected to the first pickup. The induced electromotive force of the dummy coil 1Ca is adjusted to match the first pickup by adjusting the adjustment member 3 of the dummy coil 1Ca. This allows the dummy coil 1Ca to reduce hum noise of the first pickup.

[0038] A composite dummy coil, in which dummy coils 1Ca and 1Cb are connected in series, is connected to the second pickup. The composite induced electromotive force of the dummy coils 1Ca and 1Cb is adjusted to match the second pickup by adjusting the adjustment member 3 of the dummy coil 1Cb. This allows the dummy coils 1Ca and 1Cb to reduce hum noise of the second pickup.

[0039] A composite dummy coil, in which dummy coils 1Ca, 1Cb, and 1Cc are connected in series, is connected to the third pickup. By adjusting the adjustment member 3 of the dummy coil 1Cc, the composite induced electromotive force of the dummy coils 1Ca, 1Cb, and 1Cc is adjusted to match the third pickup. This allows the dummy coils 1Ca, 1Cb, and 1Cc to reduce hum noise in the third pickup.

[0040] In this way, by using the dummy coil 1C according to the second modification, the dummy coil 1C can be made smaller. As a method for reducing the hum noise of a plurality of electromagnetic pickups, there is also a method of attaching individual dummy coils 1, 1A, 1B, etc. in one-to-one correspondence with each electromagnetic pickup. However, with the dummy coil 1C according to the second modification, the second and third pickups can ensure induced electromotive force by combining a plurality of dummy coils, so that the dummy coils 1Cb, 1Cc can be made smaller. The dummy coil 1C can also be attached to the body of the electric guitar 7 in the regions 75a to 75f shown in Figs. 9 and 10. In the second modification, the dummy coils 1Ca, 1Cb, 1Cc are configured to have different diameters at the bottom, but as another modification, the dummy coils 1Ca, 1Cb, 1Cc may be configured to have different axial lengths.

[0041] {7. Variation 3} Next, a third modification of the present invention will be described. Fig. 14 is a diagram showing a dummy coil 1D according to the third modification. The dummy coil 1D is configured with three dummy coils 1Da, 1Db, and 1Dc connected in series. The dummy coils 1Da, 1Db, and 1Dc are examples of a coil set according to the present invention. Unlike the dummy coil 1C according to the second modification, the dummy coil 1D according to the third modification is configured with three dummy coils 1Da, 1Db, and 1Dc stacked one above the other.

[0042] As shown in the figure, the three dummy coils 1Da, 1Db, and 1Dc have a structure in which they share five core materials 4a to 4e. The dummy coil 1D is provided with an adjustment member that can individually adjust the positions of the core materials 4a to 4e in the vertical direction (coil axial direction), and it is possible to adjust the core insertion length of each of the dummy coils 1Da, 1Db, and 1Dc. However, the dummy coils 1Da, 1Db, and 1Dc have different lengths in the vertical direction (axial direction) of the bobbin 2. In the example shown in FIG. 14, the axial length of the dummy coil 1Da is longer than that of the dummy coils 1Db and 1Dc. The axial lengths of the dummy coils 1Db and 1Dc are approximately the same.

[0043] The dummy coils 1Da, 1Db, and 1Dc have different axial lengths, and therefore the number of turns of the coil 20 is also different. As a result, the magnitude of the induced electromotive force in the dummy coils 1Da, 1Db, and 1Dc is also different. If the electric guitar 7 has three electromagnetic pickups (first to third pickups), the hum noise of each of the three electromagnetic pickups is reduced by combining three coil sets as follows. However, the magnitude of the induced electromotive force in each electromagnetic pickup is 1st < 2nd < 3rd.

[0044] The dummy coil 1Da is connected to the first pickup. The composite dummy coil, in which the dummy coils 1Da and 1Db are connected in series, is connected to the second pickup. The composite dummy coil, in which the dummy coils 1Da, 1Db, and 1Dc are connected in series, is connected to the third pickup. By individually adjusting the core insertion lengths of the core materials 4a to 4e, the induced electromotive force of the dummy coil 1Da is adjusted to the first pickup, the composite induced electromotive force of the dummy coils 1Da and 1Db is adjusted to the second pickup, and the composite induced electromotive force of the dummy coils 1Da, 1Db, and 1Dc is adjusted to the third pickup. As a result, the dummy coil 1Da reduces the hum noise of the first pickup, the dummy coils 1Da and 1Db reduce the hum noise of the second pickup, and the dummy coils 1Da, 1Db, and 1Dc reduce the hum noise of the third pickup.

[0045] In this way, by using the dummy coil 1D according to the third modification, it is possible to reduce the size of the dummy coil 1D. As a method for reducing hum noise of multiple electromagnetic pickups, the dummy coil 1D according to the third modification can ensure induced electromotive force by combining multiple dummy coils in the second and third pickups, making it possible to reduce the size of the dummy coils 1Db and 1Dc. The dummy coil 1D can also be attached to the body of the electric guitar 7 in areas 75a to 75f shown in Figs. 9 and 10.

[0046] {8. Other embodiments} In the above embodiment, an electric guitar 7 has been described as an example of a musical instrument using the dummy coils 1, 1A, 1B, 1C, and 1D, but the dummy coil of the present invention can be used in other musical instruments having an electromagnetic pickup. For example, it can be used in an electric bass. The dummy coil 1 of the present invention has adjustable magnetic permeability and can detect environmental magnetic field noise but not detect magnetic field changes caused by string vibration. Within the scope of its purpose, the dummy coil 1 of the present invention is not limited to the above embodiment and can be modified as appropriate.

[0047] {9. Features and Effects of the Embodiment} (1) One embodiment of the noise reduction device of the present invention is a noise reduction device that is attached to a musical instrument having an electromagnetic pickup that detects magnetic field changes due to string vibrations, and comprises a coil, a core material made of a soft magnetic material, and an adjustment member that variably adjusts the relative position of the coil and the core material, wherein the core material is not magnetized.

[0048] By increasing the apparent magnetic permeability by providing a core material, the size of the noise reduction device can be reduced while still ensuring the necessary induced electromotive force. In addition, since the relative position between the coil and the core material can be variably adjusted, the induced electromotive force can be controlled appropriately according to the musical instrument to which it is attached. This makes it possible to effectively reduce noise from the electrical signal output from the electromagnetic pickup.

[0049] (2) In the noise reduction device described in (1), the noise reduction device does not need to detect the change in the magnetic field caused by the vibration of the string at a perceptible level.

[0050] Noise can be effectively reduced from the electrical signal output from the electromagnetic pickup.

[0051] (3) In the noise reduction device described in (1), the noise reduction device may be attached to the musical instrument in a region that is not affected by magnetic field changes caused by vibration of the strings.

[0052] Noise can be effectively reduced from the electrical signal output from the electromagnetic pickup.

[0053] (4) In the noise reduction device described in (1), the core material may be inserted in the axial direction inside the coil, and the adjustment member may adjust the insertion length of the core material in the axial direction of the coil.

[0054] By adjusting the position of the core material within the coil, it is possible to adjust the induced electromotive force to reduce noise depending on the instrument.

[0055] (5) In the noise reduction device described in (4), the adjustment member may be capable of holding the core material, and the insertion length of the core material in the axial direction of the coil may be adjusted by adjusting the relative position of the adjustment member in the axial direction of the coil.

[0056] By adjusting the position of the core material within the coil, it is possible to adjust the induced electromotive force to reduce noise depending on the instrument.

[0057] (6) In the noise reduction device according to (5), the adjustment member may hold a plurality of core materials.

[0058] The apparent permeability can be adjusted.

[0059] (7) In the noise reduction device described in (1), the core material may be inserted inside the coil in the axial direction of the coil, and the adjustment member may adjust the relative position of the core material in a direction perpendicular to the axial direction of the coil.

[0060] By adjusting the position of the core material within the coil, it is possible to adjust the induced electromotive force to reduce noise depending on the instrument.

[0061] (8) In the noise reduction device described in (1), the core material may include ferrite.

[0062] The magnetic permeability of the core material can be increased.

[0063] (9) In the noise reduction device described in (1), the noise reduction device may have a plurality of coil sets each including a coil, a core material, and an adjustment member, and may generate a plurality of induced electromotive forces by combining the plurality of coil sets.

[0064] The size of the noise reduction device for generating multiple induced electromotive forces can be reduced.

[0065] (10) In the noise reduction device described in (9), the musical instrument may have a plurality of electromagnetic pickups, and the noise of each of the plurality of electromagnetic pickups may be reduced by combining a plurality of coil sets.

[0066] The size of the noise reduction device for multiple pickups can be reduced.

[0067] (11) Another aspect of the present invention provides a musical instrument that includes an electromagnetic pickup that detects magnetic field changes due to string vibrations, and a noise reduction device, the noise reduction device having a coil wound in the opposite direction to the electromagnetic pickup coil, a core material made of a soft magnetic material, and an adjustment member that variably adjusts the relative position of the coil and the core material, wherein the core material is not magnetized.

[0068] By increasing the apparent magnetic permeability by providing a core material, the size of the noise reduction device can be made small while still ensuring the necessary induced electromotive force. In addition, the relative position of the coil and the core material can be variably adjusted, so that the induced electromotive force can be controlled appropriately for each musical instrument. This makes it possible to effectively reduce noise from the electrical signal output from the electromagnetic pickup.

[0069] (12) Another aspect of the present invention provides a musical instrument that includes an electromagnetic pickup that detects magnetic field changes due to string vibrations, and a noise reduction device. The noise reduction device has a coil wound in the opposite direction to the electromagnetic pickup coil, a core material made of a soft magnetic material, and an adjustment member that variably adjusts the relative position of the coil and the core material, and the noise reduction device does not detect magnetic field changes due to string vibrations at a perceptible level.

[0070] Noise can be effectively reduced from the electrical signal output from the electromagnetic pickup.

[0071] (13) Another aspect of the present invention provides a musical instrument comprising an electromagnetic pickup that detects magnetic field changes due to string vibration, and a noise reduction device, the noise reduction device having a coil wound in the opposite direction to the coil of the electromagnetic pickup, a core material made of a soft magnetic material, and an adjustment member that variably adjusts the relative position of the coil and the core material, the noise reduction device being attached to the musical instrument in a second region different from a first region in which the electromagnetic pickup is attached, and the second region includes an area that is not affected by magnetic field changes due to string vibration.

[0072] Noise can be effectively reduced from the electrical signal output from the electromagnetic pickup.

[0073] (14) In the musical instrument described in (13), the first area and the second area may be areas that are subject to a common environmental magnetic field noise.

[0074] Noise can be effectively reduced from the electrical signal output from the electromagnetic pickup.

[0075] (15) In the musical instrument described in any one of (11) to (13), the core material may be inserted inside the coil in an axial direction of the coil, and the adjustment member may adjust an insertion length of the core material in the axial direction of the coil.

[0076] By adjusting the position of the core material within the coil, it is possible to adjust the induced electromotive force to reduce noise depending on the instrument.

[0077] (16) In the musical instrument described in (15), the adjustment member may be capable of holding the core material, and the insertion length of the core material in the axial direction of the coil may be adjusted by adjusting the relative position of the adjustment member in the axial direction of the coil.

[0078] By adjusting the position of the core material within the coil, it is possible to adjust the induced electromotive force to reduce noise depending on the instrument.

[0079] (17) In the musical instrument described in (16), the adjustment member may hold a plurality of core materials.

[0080] The apparent permeability can be adjusted.

[0081] (18) In the musical instrument described in any one of (11) to (13), the core material may be inserted axially inside the coil, and the adjustment member may adjust the relative position of the core material in a direction perpendicular to the axial direction of the coil.

[0082] By adjusting the position of the core material within the coil, it is possible to adjust the induced electromotive force to reduce noise depending on the instrument.

[0083] (19) In the musical instrument according to any one of (11) to (13), the core material may contain ferrite.

[0084] The magnetic permeability of the core material can be increased.

[0085] (20) In the musical instrument described in any one of (11) to (13), the noise reduction device may have a plurality of coil sets each consisting of a coil, a core material, and an adjustment member, and the musical instrument may have a plurality of coil sets, and a plurality of induced electromotive forces may be generated by combining the plurality of coil sets.

[0086] The size of the noise reduction device for generating multiple induced electromotive forces can be reduced.

[0087] (twenty one) In the musical instrument described in (20), the musical instrument may have a plurality of electromagnetic pickups, and the noise of each of the plurality of electromagnetic pickups may be reduced by combining a plurality of coil sets.

[0088] The size of the noise reduction device for multiple pickups can be reduced. [Explanation of symbols]

[0089] 1, 1A, 1B, 1C, 1D... dummy coil, 2... bobbin, 20... coil, 21... (bobbin) cylindrical portion, 21a... screw groove, 22... (bobbin) disc portion, 23... space, 3... adjustment member, 31... (adjustment member) upper surface, 31S... hole (for inserting core material), 32... cylindrical portion, 32a... screw groove, 4, 4a to 4e... core material, 5... dial, 7... electric guitar, 70... body, 70F... front side of body, 70B... rear side of body, 71... string, 72... electromagnetic pickup, 75a to 75f... mounting area of ​​dummy coil, U... up direction, D... down direction, L... left direction, R... right direction

Claims

1. A noise reduction device that is attached to a musical instrument having an electromagnetic pickup that detects magnetic field changes due to vibration of a string, A coil and A core material made of a soft magnetic material; an adjustment member that variably adjusts the relative position of the coil and the core material; Equipped with A noise reduction device, wherein the core material is not magnetized.

2. 10. The noise reduction device of claim 1, wherein the noise reduction device does not detect appreciable changes in magnetic field due to vibration of the string.

3. The noise reduction device of claim 1 , wherein the noise reduction device is attached to the musical instrument in an area that is not affected by magnetic field changes due to vibration of the strings.

4. The core material is inserted in the axial direction inside the coil, The noise reduction device according to claim 1 , wherein the adjustment member adjusts an insertion length of the core material in an axial direction of the coil.

5. The noise reduction device according to claim 4 , wherein the adjustment member is capable of holding the core material, and an insertion length of the core material in the axial direction of the coil is adjusted by adjusting a relative position of the adjustment member in the axial direction of the coil.

6. The noise reduction device of claim 5 , wherein the adjustment member holds a plurality of cores.

7. The core material is inserted into the coil in an axial direction of the coil, The noise reduction device according to claim 1 , wherein the adjustment member adjusts a relative position of the core material in a direction perpendicular to an axial direction of the coil.

8. The noise reduction device of claim 1 , wherein the core material comprises ferrite.

9. The noise reduction device according to claim 1 , further comprising a plurality of coil sets each including the coil, the core material, and the adjustment member, and a plurality of induced electromotive forces are generated by combining the plurality of coil sets.

10. 10. The noise reduction device according to claim 9, wherein the musical instrument has a plurality of electromagnetic pickups, and the combination of the plurality of coil sets reduces noise from each of the plurality of electromagnetic pickups.

11. an electromagnetic pickup that detects magnetic field changes based on the vibration of the string; A noise reduction device; A musical instrument comprising: The noise reduction device comprises: a coil wound in the opposite direction to the coil of the electromagnetic pickup; A core material made of a soft magnetic material; an adjustment member that variably adjusts the relative position of the coil and the core material; having A musical instrument, wherein the core material is not magnetized.

12. an electromagnetic pickup that detects magnetic field changes based on the vibration of the string; A noise reduction device; A musical instrument comprising: The noise reduction device comprises: a coil wound in the opposite direction to the coil of the electromagnetic pickup; A core material made of a soft magnetic material; an adjustment member that variably adjusts the relative position of the coil and the core material; having The musical instrument, wherein the noise reduction device does not detect appreciable changes in magnetic field due to vibration of the strings.

13. an electromagnetic pickup that detects magnetic field changes based on the vibration of the string; A noise reduction device; A musical instrument comprising: The noise reduction device comprises: a coil wound in the opposite direction to the coil of the electromagnetic pickup; A core material made of a soft magnetic material; an adjustment member that variably adjusts the relative position of the coil and the core material; having The noise reduction device is attached to the musical instrument in a second area different from a first area in which the electromagnetic pickup is attached, the second area including an area that is not affected by magnetic field changes due to vibration of the strings.

14. 14. The musical instrument of claim 13, wherein the first area and the second area are areas subject to a common environmental magnetic field noise.

15. The core material is inserted into the coil in an axial direction of the coil, The musical instrument according to any one of claims 11 to 13, wherein the adjustment member adjusts an insertion length of the core material in an axial direction of the coil.

16. The musical instrument according to claim 15 , wherein the adjustment member is capable of holding the core material, and the insertion length of the core material in the axial direction of the coil is adjusted by adjusting the relative position of the adjustment member in the axial direction of the coil.

17. 17. The musical instrument of claim 16, wherein the tuning member holds a plurality of cores.

18. The core material is inserted in the axial direction inside the coil, The musical instrument according to any one of claims 11 to 13, wherein the adjustment member adjusts the relative position of the core material in a direction perpendicular to an axial direction of the coil.

19. The musical instrument according to any one of claims 11 to 13, wherein the core material comprises ferrite.

20. The musical instrument according to any one of claims 11 to 13, wherein the noise reduction device has a plurality of coil sets each composed of the coil, the core material, and the adjustment member, and the musical instrument has the plurality of coil sets, and a plurality of induced electromotive forces are generated by combining the plurality of coil sets.

21. 21. The musical instrument of claim 20, wherein the musical instrument has multiple electromagnetic pickups, and the multiple coil sets in combination reduce noise for each of the multiple electromagnetic pickups.

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