Loudspeaker with magnetic flux following voice coil

Abstract

The invention provides a loudspeaker with a magnetic flux following a voice coil, the loudspeaker comprises a diaphragm connected with a coil assembly, and the coil assembly is configured to electromagnetically drive the diaphragm. The coil assembly comprises a voice coil and a voice coil frame, and the voice coil is wound on the voice coil frame. Wherein the voice coil frame is at least partially or completely formed from a material having a high permeability characteristic. The speaker also includes a magnet assembly. The magnet assembly includes a permanent magnet and at least one pole piece, where the magnet assembly is coaxially disposed with the coil assembly, and the magnet assembly is configured to provide a gap to receive the coil assembly between poles of the magnet assembly. The present application improves the sound of the speaker without increasing the size or power consumption of the speaker.

Description

Technical Field

[0001] The present invention relates generally to the field of loudspeakers. In particular, the present invention relates to a loudspeaker that helps improve sound quality without increasing the size and / or input power of the loudspeaker. Background Art

[0002] A loudspeaker is used to convert electrical energy into acoustic energy, where sound is produced when a vibrating object (usually a diaphragm) creates sound waves in the air. A loudspeaker generally consists of a diaphragm, a coil of wire (called a voice coil), and a permanent magnet. The voice coil is usually attached to the narrower end of the diaphragm. The voice coil is suspended in the gap between the poles of the permanent magnet, which generates a magnetic field within the gap.

[0003] When a wire carrying an electric current is placed in a magnetic field, the interaction between the magnetic field and the moving charges in the wire causes a force to act on the wire. Therefore, when a changing electrical signal is applied to the terminals of the voice coil, the interaction between the magnetic field of the permanent magnet and the magnetic field generated by the movement of the current in the voice coil produces a force acting on the voice coil. Depending on the polarity of the applied signal, the force acting on the voice coil pushes or pulls the voice coil relative to the permanent magnetic field. This in turn causes the diaphragm attached to the voice coil to vibrate back and forth and act on the air to produce sound waves.

[0004] To increase the intensity of the sound waves, you need to increase the distance, speed, acceleration, and strength of the diaphragm's vibrations - hereafter described as the "intensity" of the motion. Since the diaphragm is driven by the voice coil, the intensity of the voice coil's motion plays an important role. To increase the intensity of the voice coil's motion, you need to increase the force acting on the voice coil.

[0005] The force acting on the current in the magnetic field is calculated according to the following equation:

[0006] F=BIL

[0007] The force on the wire (F) is proportional to the current through the wire (I), the length of the conductor in the magnetic field (L), and the flux density of the magnetic field (B). By controlling each, some, or all of these parameters, the magnitude and / or direction of the force acting on the voice coil will be changed.

[0008] However, increasing the length (L) of the voice coil is not always desirable: this requires more space to accommodate the voice coil, which in turn leads to an increase in the size of the loudspeaker. In addition, an increase in the voice coil length leads to an increase in the required wire length, which in turn increases the weight - which is undesirable for a loudspeaker.

[0009] As another option, the current (I) applied to the voice coil can be increased to increase the force. The electrical signal applied comes from an amplifier, and the signal current can be increased by applying more power to said amplifier. However, this increase in current is expensive because more power is required. Additionally, the amplifier is an external entity to the loudspeaker, so the output of the amplifier cannot usually be adjusted within or by the loudspeaker. This means that the loudspeaker must always be operated with a high-power amplifier to achieve the required force. Therefore, this option means that the efficiency of the loudspeaker is related to the amplifier, not the loudspeaker itself.

[0010] Furthermore, increasing the current applied to the voice coil is generally undesirable as this may result in excessive heating near the voice coil. This excessive heating may be more problematic when the gap between the poles of the magnet structure needs to be kept as small as possible in order to concentrate the magnetic flux within the gap. This, in turn, may result in expansion of the voice coil and subsequent friction of the voice coil against the top plate. Ultimately, this excessive heating may result in distortion of the sound and, in extreme cases, may even lead to damage to the voice coil.

[0011] It is possible to increase the force on the voice coil without requiring a high-power amplifier or increasing the size of the speaker. This can be achieved by increasing the flux density (B) value, since the density of the flux density (B) increases the force applied to the voice coil in proportion. To achieve this effect, the flux needs to be confined near the voice coil, thereby maximizing the force applied to the voice coil. The traditional way to increase the flux density (B) is to use larger and / or stronger magnets. However, such magnets are generally more expensive, require more space, and can be heavier - all undesirable attributes in speaker design.

[0012] Patent document US 6,868,165 B1 shows a conventional loudspeaker assembly having a magnet structure, a voice coil and a diaphragm connected to a voice coil frame, and the voice coil is wound on the voice coil frame. The voice coil frame is a rigid cylinder made of paper, Or made of aluminum.

[0013] The magnet structure in the prior art includes an annular permanent magnet with an annular opening in the middle. A T-shaped pole piece is attached to the bottom surface of the permanent magnet so that the column of the T-shaped pole piece extends through the annular opening of the permanent magnet. An annular top plate is attached to the top surface of the permanent magnet. The annular top plate has an opening that matches the size of the column of the T-shaped pole piece. The annular top plate and the T-shaped pole piece define a gap for accommodating a voice coil. A magnetic flux path is formed in the gap between the top plate and the column.

[0014] In order to improve the overall efficiency of the loudspeaker, the prior art proposes to increase the magnetic flux density by keeping the gap as small as possible so that the magnetic flux can be concentrated near the voice coil. However, this does increase the probability of contact between the voice coil and the annular top plate or between the voice coil and the T-shaped magnetic pole piece, which in turn may cause sound distortion. Since the dimensions of the T-shaped magnetic pole piece and the annular top plate need to be accurate during the manufacturing process, a higher manufacturing tolerance is required, thereby increasing the manufacturing cost of the loudspeaker.

[0015] Patent document US 7,778,436 B2 discloses a loudspeaker, which includes a diaphragm and a vibrating portion, the vibrating portion having a magnet and two yokes. The magnet and the two yokes are spaced apart from the diaphragm by a suitable distance. The diaphragm is attached to a voice coil former.

[0016] The magnet in the prior art is a permanent magnet formed of ferrite or neodymium and has a disc shape. The north pole of the magnet contacts the lower surface of the upper yoke, and the south pole of the magnet is connected to the upper surface of the U-shaped lower yoke. The voice coil is made by winding a coil on a voice coil former made of copper or aluminum. The voice coil is located between the magnetic poles of the magnet, wherein when current is applied to the voice coil, the voice coil pulls or pushes the diaphragm to generate sound waves.

[0017] In this prior art document, in order to achieve an increase in magnetic flux density, the yoke is formed by injection molding of a mixture of iron, tungsten and nickel powders and sintering of these materials. The yoke may also be formed of tungsten or alloys such as Permalloy, Mo Permalloy, Mumetal and Supermalloy.

[0018] It is known and related to US 7,778,436 that the magnetic field (H) and the magnetic flux density (B) are related by the following equation:

[0019] B=μH

[0020] μ here represents the magnetic permeability. A material with a higher magnetic permeability is desirable in a magnetic field because a higher magnetic permeability material can increase the magnetic flux passing through it.

[0021] Due to the high magnetic permeability of these materials, the magnetic flux from the north pole of the U-shaped yoke is concentrated around the voice coil. As a result, the magnetic flux density through the voice coil is increased. Accordingly, the force applied to the voice coil is increased and the movement of the voice coil is enhanced. Since the movement of the diaphragm is directly related to the movement of the voice coil, the quality of the sound is improved. This known method achieves an increase in the magnetic flux density near the voice coil without increasing the size of the loudspeaker or without increasing the amount of applied current.

[0022] However, in these known loudspeakers, the use of the above-mentioned materials with high magnetic permeability in manufacturing the yoke increases the overall weight of the loudspeaker, and especially increases the cost of the loudspeaker. In particular, alloys such as Permalloy, Mumetal, Super-Mu Alloy, and Super-Mu Alloy cost more than iron, steel, or other materials commonly used to manufacture the yoke.

[0023] It would therefore be desirable to manufacture loudspeakers with improved sound as efficiently, effectively, and economically as possible without increasing the size or power consumption of the loudspeakers. Summary of the invention

[0024] The present invention is proposed to solve the above technical problems, and provides a loudspeaker. The loudspeaker includes a diaphragm connected to a coil assembly, wherein the coil assembly is configured to electromagnetically drive the diaphragm. The coil assembly includes a voice coil and a voice coil frame. The voice coil is wound on the voice coil frame. The voice coil frame is at least partially or completely formed of a material with high magnetic permeability properties. The loudspeaker also includes a magnet assembly. The magnet assembly includes a permanent magnet and at least one pole piece, wherein the magnet assembly is coaxially arranged with the coil assembly, and the magnet assembly is configured to provide a gap to accommodate the coil assembly between the poles of the magnet assembly.

[0025] The beneficial effects of the present application are as follows: One aspect of the present invention is to concentrate the magnetic flux generated near the voice coil.

[0026] The gap between the voice coil and the magnet is filled with air. A high magnetic permeability material is used in the voice coil former around which the voice coil is wound to increase the magnetic field strength (magnetic flux density) in the gap, thereby increasing the magnetic flux density passing around the voice coil.

[0027] High permeability materials are defined herein as having a relative permeability of 10,000 or more and include materials such as: mu-metal, supermalloy, supermumetal, nilomag, sanbold, molybdenumpermalloy, permalloy, Mo Permalloy, and Supermalloy. These materials provide a low reluctance path for magnetic flux. Therefore, in the magnetic circuit, these materials provide a preferred path for magnetic flux in a closed area relative to air. Therefore, materials such as mu-metal or other high permeability materials have the effect of increasing the magnetic field in the gap between the magnet assembly and the voice coil.

[0028] The use of materials such as mu metal or other high permeability materials to make the magnet assembly can have the effect of increasing the magnetic flux density in the gap between the magnet assembly and the voice coil without reducing the size of the gap or increasing the cost. The presence of high permeability materials tends to restrict magnetic flux in preference to other areas, which in turn increases the magnetic flux density in the gap. Thus, the present invention is directed to a loudspeaker including a voice coil former made of mu metal or other high permeability material that can significantly improve the effective sound quality and efficiency of the loudspeaker compared to similarly sized loudspeakers - in large part by concentrating the magnetic field at strategic points in the loudspeaker.

[0029] Thus, the present invention is able to improve the sound in a loudspeaker without necessarily increasing weight / size and without significantly increasing material costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A cross-sectional view of a loudspeaker assembly according to the present invention is shown.

[0031] Figure 2 is a cross-sectional view of an example of a speaker assembly according to the present invention.

[0032] Figure 3 A magnetic flux diagram of a loudspeaker assembly according to the prior art is shown.

[0033] Figure 4 A magnetic flux diagram of a loudspeaker assembly according to the present invention is shown when the voice coil is at a maximum height.

[0034] Figure 5 A magnetic flux diagram of a loudspeaker assembly according to the present invention is shown.

[0035] Figure 6 A graph is shown to illustrate the force factor BL(x) versus displacement (x) of the present invention compared to the force factor BL(x) versus displacement (x) of the prior art.

[0036] Figure 7 Another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0037] Reference Figure 1 , provides a cross-sectional view of a loudspeaker 10 according to a non-limiting embodiment of the present invention. The loudspeaker 10 includes a frame 13 having a frusto-conical shape and a magnet assembly mounted at a smaller end of the frame 13.

[0038] The loudspeaker 10 may include a diaphragm 12. The diaphragm 12 generally has a membrane element, which may generally have the shape of a truncated section of a cone or a laterally curved cone. And a dust cover membrane 15 extends through the narrower portion of the diaphragm 12. The diaphragm 12 may be mounted in the frame 13 by, for example, bonding, welding or other known techniques, so that the wider end of the diaphragm is fixed to the wider end of the frame.

[0039] The cylindrical voice coil former 2 extends from the narrower area of ​​the diaphragm 12 in the direction towards the magnet assembly. The outer surface of the voice coil former 2 is arranged coaxially with the axis 6. The axis 6 is the central axis of the diaphragm 12, the magnet assembly and generally the central axis of the loudspeaker 10.

[0040] Preferably, the centering blade 14 extends from the narrower end of the diaphragm to the inner side of the frame 13. The centering blade 14 is configured to fix the voice coil former 2 to the frame 13. The centering blade 14 can be formed of a rubber material. The centering blade 14 is connected to the lower part of the diaphragm 12 and can prevent the voice coil former 2 from moving in a direction perpendicular to the axis 6.

[0041] A voice coil 1 such as a wire is wound on the outer surface of a voice coil former 2. And the voice coil 1 has a pair of leads (not shown) that receive an electrical signal from an external amplifier. The electrical signal is usually a changing signal and can be converted into a sound output. The leads of the voice coil 1 are usually mounted on the diaphragm 12 so that the leads do not interfere with the movement of the voice coil assembly. For example, the leads of the voice coil 1 are mounted on the diaphragm 12 using glue. However, the voice coil 1 is not always mounted on the diaphragm 12. The voice coil 1 is usually made of copper, silver or other known and suitable conductors.

[0042] Figure 2 , a magnet assembly and a voice coil assembly are shown. The magnet assembly generally has an annular permanent magnet 4. The permanent magnet 4 may have a hole in the middle and a square or rectangular shape. The permanent magnet 4 is sandwiched between an annular top plate 3 and a back plate 5. The annular top plate 3 and the back plate 5 are made of a magnetically conductive material such as iron, steel, iron alloy, nickel alloy or cobalt alloy.

[0043] Preferably, the back plate 5 is circular. The back plate 5 is attached to an annular surface of the annular permanent magnet 4. And the back plate 5 and the annular permanent magnet 4 usually have similar or equal outer diameters. Figure 2 In the embodiment of the present invention shown, a T-shaped back plate 5 is used. However, a U-shaped back plate 5 can also be used in the present invention to achieve the same effect.

[0044] exist Figure 2In the embodiment shown, the back plate 5 has an extended pole piece 8, thereby forming a T-shaped piece. The extended pole piece 8 is an element of the back plate 5, which extends generally toward the diaphragm 12 in a direction along the central axis 6 of the magnet assembly. The end of the extended pole piece 8 farthest from the back plate 5 is located near the inner annular surface of the top plate 3. Therefore, a radial gap 7 is formed between the outer surface of the pole piece 8, the inner annular surface of the top plate 3 and the cylindrical inner surface of the annular magnet 4.

[0045] The top plate 3 is mounted on the other side of the annular permanent magnet 4 on the back plate 5. The top plate 3 has an annular shape, and its outer diameter is generally similar to the outer diameter of the back plate 5, and its inner diameter is generally smaller than the inner diameter of the annular permanent magnet 4. Preferably, the annular permanent magnet 4, the back plate 5 and the top plate 3 are coaxially arranged about the axis 6. The top plate 3 and the back plate 5 are respectively connected or fixed to the upper surface and the lower surface of the magnet 4 by welding or adhesive bonding. When the top plate 3 and the back plate 5 are fixed to the annular magnet 4, the combination of the top plate 3, the back plate 5 and the annular magnet 4 forms a magnetic flux path passing through the radial gap 7.

[0046] The voice coil assembly of the loudspeaker 10 is located in a radial gap 7 defined by the inner surface of the top plate 3 and the outer surface of the extended pole piece 8. Preferably, the top plate 3 and the back plate 5 are made of ferromagnetic materials such as nickel or iron. The size of the radial gap 7 can be set to accommodate the lower end of the voice coil former 2 and the voice coil 1.

[0047] The voice coil assembly includes a voice coil 1 wound on a voice coil former 2. When an electrical signal is applied to the terminals of the voice coil 1, the current flowing through the multi-turn voice coil 1 generates a changing magnetic field. The magnetic field generated by the voice coil 1 interacts with the magnetic field of the magnet assembly. This interaction generates a force on the voice coil assembly and generally moves the voice coil assembly in a direction parallel to the axis 6. The direction of this movement is determined by the polarity of the applied electrical signal. Since the voice coil assembly is attached to the diaphragm 12, the diaphragm 12 moves together with the voice coil former 2 toward the magnet assembly, or together away from the magnet assembly. The resulting back and forth movement causes the diaphragm 12 to vibrate and push the air in front of the diaphragm 12, thereby generating a pressure difference that propagates in the form of sound waves.

[0048] Ideally, the radial gap 7 is as small as possible to maximize the magnetic force applied to the voice coil so as not to interfere with the free movement of the voice coil 1. For this reason, the gap between the extended pole piece 8 and the top plate 3 is maintained between 0.2 mm and 1 mm. Preferably, the gap between the extended pole piece 8 and the top plate 3 is maintained between 0.2 mm and 0.6 mm. Depending on the type of driver and its intended use, the gap between the top plate 3 and the moving voice coil 1 and the gap between the voice coil former 2 and the pole piece 8 are maintained between 0.05 mm and 0.75 mm, preferably, the gap between the top plate 3 and the moving voice coil 1 and the gap between the voice coil former 2 and the pole piece 8 are maintained between 0.15 mm and 0.5 mm.

[0049] The magnetic flux density passing through the voice coil 1 has a direct effect on the strength of the movement of the voice coil 1. This is because the movement of the voice coil is caused by the interaction between the magnetic field generated by applying an electrical signal to the voice coil 1 and the magnetic field of the magnet assembly. In order to maximize the force applied to the voice coil 1, the magnetic flux needs to be concentrated within the radial gap 7.

[0050] The radial gap 7 is typically filled with the ambient atmosphere when the loudspeaker 10 is in use, which means that the magnetic flux tends to spread out when passing through the radial gap 7, and the magnetic flux has a reduced concentration compared to the magnetic flux in the top plate 3 and the back plate 5. In order to concentrate the magnetic flux within the radial gap 7, and critically without increasing the size, cost or power of the applied signal of the loudspeaker, the present invention uses a material with high magnetic permeability to form the voice coil former 2. In the context of the present invention, a high magnetic permeability material is considered to be a material with a relative magnetic permeability equal to or greater than 10,000.

[0051] Figure 3 2 shows a cross-sectional view of magnetic flux lines, which represent the magnetic flux generated by a conventional or prior art speaker around the magnet assembly 23, 24 and the coil assembly. For comparison, Figure 4 and Figure 5 FIG. 1 shows a cross-sectional view of the magnetic flux lines of the magnet assembly and the voice coil assembly according to the present embodiment. The magnetic flux lines represent the density of the magnetic field. Figure 3 compared to, Figure 4 and Figure 5 The denser magnetic flux lines shown in the radial gap 7 in FIG. 1 show that the present invention achieves an increased magnetic field density.

[0052] Figure 3 1 shows the magnetic flux lines around the voice coil assembly. In this conventional loudspeaker, the voice coil former 22 is made of paper, KAPTON TM 、NOMEX TM , aluminum or any other standard material. It can be seen that the magnetic flux lines in the radial gap 27 are not greatly affected by the voice coil former 22, or are not even affected by the voice coil former 22, so the magnetic flux lines in the radial gap 27 are not concentrated near the voice coil 21. The magnetic field formed in the radial gap 27 is usually caused by the ambient atmosphere in the radial gap 27.

[0053] exist Figure 4 and Figure 5 In the embodiment, the magnetic flux lines near the voice coil assembly are more concentrated around the voice coil former 2 than in the conventional case. By means of a high magnetic permeability material, for example, by means of a voice coil former 2 constructed of a high magnetic permeability alloy (mu-metal) material, a preferred path for the magnetic field to pass through the radial gap 7 can be provided. Figure 4 and 5 It is clearly shown that Figure 3Compared to the conventional loudspeaker shown, the density of magnetic flux lines is greater in the region of radial gap 7. The increase in the density of magnetic flux lines indicates a higher magnetic flux.

[0054] When the voice coil former 2 is formed of a material having a high magnetic permeability such as a mu metal, the magnetic flux lines can be more concentrated on the voice coil former 2. Figure 4 and Figure 5 , especially with Figure 3 Compared with the conventional speaker shown in FIG. 1 , the magnetic field density passing through the voice coil 1 in the present invention is increased. Figure 3 As can be seen in FIG. 2 , the magnetic field in the radial gap 27 is not modified by any material near the voice coil former 22. In contrast, Figure 4 and Figure 5 The magnetic field is more concentrated in the area of ​​voice coil 1.

[0055] The use of high magnetic permeability materials, such as mu-metal, supermalloy, supermumetal, nilomag, sanbold, molybdenum permalloy, Mo permalloy, Supermalloy or other similar materials, provides a low magnetic resistance path for the magnetic field passing through the radial gap 7. Therefore, the use of high magnetic permeability materials for the voice coil former 2 has the effect of increasing the density of the magnetic field passing through the voice coil former 2 and its surrounding areas. Due to the increase in magnetic flux, the force applied to the voice coil 1 is also increased, thereby enhancing the vibration strength of the voice coil 1. As a result, the improvement of the speaker performance is achieved.

[0056] The high magnetic permeability material is preferably a mu alloy. Mu alloy is a high magnetic permeability soft magnetic alloy and has a higher saturation value than other high magnetic permeability materials. Mu alloy also has the advantages of being ductile, plastic and processable, and is therefore easily formed into a thin sheet. In the present embodiment, a mu alloy is used to manufacture the voice coil former 2 because the mu alloy has a relative magnetic permeability value of 50,000 μ / μ0, which is significantly higher than conventional materials (such as iron, steel, aluminum and paper) used to manufacture voice coil formers of conventional speakers.

[0057] The magnetic force applied to the voice coil 1 is an important parameter for obtaining a high mechanical force to move the diaphragm 12 back and forth. Due to the high magnetic permeability characteristics of the highly permeable alloy, the magnetic field is concentrated on the voice coil former 2 and the voice coil 1, thereby increasing the magnetic flux density of the magnetic field in the radial gap 7. Even when the power of the input signal from the external amplifier is low, the voice coil former provides a better magnetic flux path, so that the magnetic field strength acting on the voice coil 1 will increase, so that the movement of the voice coil former 2 and the diaphragm 12 will be guaranteed. Even in the case of low power input, the increased magnetic flux density can still allow the movement of the voice coil 1 to be sufficient to accurately reproduce the sound to be output. In this way, a high-response speaker can be obtained.

[0058] Figure 5 The figure shows the magnetic flux lines of the loudspeaker 10 when the voice coil 1 according to the present invention is located above the radial gap 7. It can be seen that the magnetic field will still be concentrated on the voice coil 1 even when the voice coil moves further away and out of the radial gap 7.

[0059] Since the voice coil former 2 includes a high magnetic permeability material, the voice coil former 2 provides a low magnetic resistance path for the magnetic field. In this way, the voice coil former 2 provides a preferred path for the magnetic field, thereby increasing the magnetic flux density. Therefore, when the voice coil former 2 moves, the magnetic field moves with the voice coil former 2 and the voice coil 1. In essence, the magnetic field moves with the voice coil assembly, so the magnetic field around the voice coil 1 increases.

[0060] Figure 6 The nonlinear force factor characteristic BL(x) of the present invention and a conventional loudspeaker is shown as a function of the displacement x of the voice coil 1. In the figure, B is the magnetic flux and L is the length of the voice coil wire. Figure 6 The BL curve is shown as the voice coil 1 moves up and down along the axis 6. The force factor BL(x) is an important factor for linearity, as it defines the maximum linear excursion that the loudspeaker can achieve, where force = BLI is the average value. BL(x) is also a determining factor for driver efficiency and sensitivity. Figure 6 It can be seen that the force factor BL(x) obtained by the present invention is about 20% higher than the force factor measured in the conventional loudspeaker. The performance of the loudspeaker of the present invention is improved due to the higher efficiency of the driver.

[0061] Figure 7 Another embodiment according to the present invention is shown. The voice coil former is not made entirely of a high magnetic permeability material (preferably, a high magnetic permeability alloy material), but a collar 32 made of a high magnetic permeability alloy is added to the voice coil former 31. Because the collar 32 concentrates the magnetic field within the radial gap 7, this structure can still increase the magnetic field density within the voice coil 1. The provision of the collar 32 in the above embodiment helps to reduce the weight, size and cost of the voice coil former 31. In this case, the voice coil former 31 can be made of aluminum, paper, Or one or more of any other suitable materials.

[0062] By providing a voice coil former 2 constructed of a metal having a high magnetic permeability as described in the present invention, the present invention can achieve a significant improvement in diaphragm vibration and sound quality for the same input signal compared to the absence of such a high magnetic permeability material in the radial gap 7 of the loudspeaker. In addition, the loudspeaker of the present invention can be made smaller than conventional designs, but still produce the same sound output. Compared to the cited prior art literature using a high magnetic permeability alloy in the magnet assembly, the present invention saves weight and cost by using a high magnetic permeability alloy only in the voice coil former 2, while still improving the performance of the loudspeaker 10.

Claims

1. A speaker, comprising: A voice coil assembly, comprising a voice coil and a voice coil former around which the voice coil is wound; and a diaphragm coupled to the voice coil assembly, wherein the voice coil assembly is configured to electromagnetically drive the diaphragm, The voice coil former is at least partially or completely formed of a material having a high magnetic permeability characteristic, or includes at least a portion of a material having a high magnetic permeability characteristic.

2. The loudspeaker according to claim 1, wherein The material is one of a high magnetic permeability alloy, a super permalloy, an ultra-high magnetic permeability alloy, a Nilomag, a Sambold, a molybdenum permalloy, a nickel-iron-molybdenum magnetic permeability alloy and a nickel-iron-molybdenum superconducting magnetic alloy.

3. The speaker according to claim 1, further comprising: A magnet assembly includes a permanent magnet and at least one pole piece, wherein the magnet assembly is coaxially disposed with the voice coil assembly and the magnet assembly is configured to provide a gap between the poles of the magnet assembly to accommodate the voice coil assembly.

4. The loudspeaker according to claim 3, wherein: The magnet assembly includes a top plate and a back plate as pole pieces and an annular permanent magnet, wherein the annular permanent magnet is sandwiched between the top plate and the back plate, and the back plate and the top plate are coaxially mounted on the central axis of the diaphragm, the magnet assembly and the speaker.

5. The loudspeaker according to claim 4, wherein: The top plate and the rear plate are magnetically conductive.

6. The loudspeaker according to claim 4, wherein: The back plate has an extension piece extending from the center of the back plate, and a diameter of the extension piece is smaller than a diameter of the back plate.

7. The loudspeaker according to claim 6, wherein: The top panel has an opening sized to fit within the extension piece.

8. The loudspeaker according to claim 4, wherein: The voice coil assembly is configured to move along the central axis.

9. The loudspeaker according to claim 1, wherein The voice coil former is formed of a first material, and one or more rings of high magnetic permeability material are formed on a surface of the voice coil former.

10. The loudspeaker according to claim 9, wherein: The voice coil frame is made of aluminum, paper, and Made of one or more materials.

Images