A dynamic earphone with adjustable closed space size and EQ adjustment method thereof

Abstract

The present invention relates to a dynamic headphone with adjustable closed space size and an EQ adjustment method thereof. An external shell is formed in a wooden structure, a closed space is formed inside the shell, and an echo chamber is formed in the spatial structure. The size of the closed space between the dynamic unit and the wooden shell that actually participates in the echo is adjusted by a space adjustment unit. A rotating soundproofing board and a wooden shell with a water droplet-shaped curved surface are provided so that when the two soundproofing boards rotate as a whole, they can move relative to the wooden shell, thereby finely adjusting the frequency response curve of the echo chamber; when the two soundproofing boards rotate relative to each other, the frequency response curve of the echo chamber can be adjusted over a large range. A new soundproofing board screening method and EQ adjustment method have been designed, which can adjust the frequency response curve of the headphone over a larger range and in a more delicate manner, thereby improving the sound quality and enhancing the listening experience.

Description

Technical Field

[0001] The present invention relates to the field of headphones, and in particular to a dynamic headphone with adjustable closed space size and an EQ adjustment method thereof. Background Art

[0002] Dynamic headphones operate similarly to conventional speakers: a coil of wire in a permanent magnetic field connected to a diaphragm, which, driven by a signal current, produces sound. Wooden headphones are popular with users for their more balanced and natural sound, improved sound quality, excellent sound reproduction, and elegant appearance.

[0003] For wooden headphones, different types of wood vary in density, elasticity, porosity, fiber shape, and adhesion. This results in significant differences in fundamental resonant frequency and material damping factor between different wood types. As a result, the frequency response characteristics of different headphones from different batches of wood, or even from the same batch of wood, can vary slightly, leading to poor sound uniformity in actual headphone production.

[0004] The Harman Target Curve is a theoretical target sound characteristic that produces the optimal sound quality preferred by most listeners. It was developed in 2012 by scientist and audio engineer Sean Olive, who described the relationship between the perception and measurement of headphone sound quality. Headphones are typically tuned to closely match the Harman curve to achieve optimal sound quality.

[0005] Therefore, it is necessary to design a headset that can adjust the EQ frequency response curve. The frequency response curve of the headset can be adjusted during production to improve its uniformity. At the same time, the user can adjust the EQ frequency response curve as needed during actual use. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a closed space size adjustable dynamic earphone, including an earpiece and a headband.

[0007] The earphones are dynamic headphones with two earphones connected by a headband.

[0008] The earpiece includes a soundproof cover module, a dynamic unit, a space adjustment unit and a wooden shell;

[0009] A closed space is formed between the interior of the wooden shell and the dynamic coil unit, and the closed space forms an echo chamber. The size of the closed space between the dynamic coil unit and the wooden shell that actually participates in the echo is adjusted by the space adjustment unit.

[0010] The material of the wooden shell is beech, rosewood, maple, alder, swamp ash, basswood or mahogany.

[0011] A ring-shaped sponge cover is provided on one side of the sound enclosure module; a dynamic unit is installed on the other side of the sound enclosure module; the diameter of the dynamic unit is smaller than the diameter of the sound enclosure module; the edge of the wooden shell is installed in contact with the edge of the sound enclosure module;

[0012] The sound emission direction of the dynamic unit is toward the annular center of the sponge cover on the sound insulation cover module; and a space adjustment unit is arranged between the dynamic unit and the wooden shell.

[0013] The space adjustment unit includes two parabolic sound insulation boards set in front and back, and are made of wood. The sound insulation boards divide the wooden shell and the dynamic unit into two parts, and there are holes distributed on the sound insulation boards.

[0014] The vertices of the front and rear sound insulation boards are connected by a rotating shaft, and a rotation drive device is set at the edges of the two sound insulation boards, so that the sound insulation boards can rotate around the axis. The hole distribution size and position of the two sound insulation boards are different. During rotation, different holes are connected, so that the space between the dynamic unit and the wooden shell is connected through multiple connected holes.

[0015] The material of the sound insulation board is different from that of the wooden shell, and the density of the material of the sound insulation board is lower than that of the wooden shell.

[0016] An annular frame is provided at the edge of the sound insulation board, and the outer surface of the annular frame is rack-shaped. The rotation drive device is a plurality of motor-driven gears arranged around the annular frame; the motor is fixed on the wooden shell, and at least three gears fix the annular frame, and the rotation of the gears drives the annular frame to rotate; each sound insulation board has an independent gear drive, so that the sound insulation boards can rotate relative to each other.

[0017] The shape of the hollowed-out inner surface of the wooden shell is as follows:

[0018] The straight line where the axis of the dynamic unit is located is the X-axis, and the vertical direction in the plane where the wooden shell and the soundproof cover are in contact is the Y-axis; the intersection line of the inner surface of the wooden shell in the XY plane conforms to the equation:

[0019] [(qy+r) 2 +(px) 2 ] 2 -2(qy+r)[(qy+r) 2 +(px) 2 ]+3(px) 2 =0;

[0020] Where p, q, and r are non-zero constant coefficients, and the above equation is named curve I;

[0021] The inner surface of the wooden shell conforms to the surface formed by rotating the curve I around the Y axis, that is, a teardrop-shaped surface.

[0022] A rotating sound insulation board and a water drop-curved wooden shell are provided so that when the two sound insulation boards rotate as a whole, they can move relative to the wooden shell, thereby finely adjusting the frequency response curve of the echo chamber; when the two sound insulation boards rotate relative to each other, the frequency response curve of the echo chamber can be adjusted over a large range.

[0023] A method for adjusting EQ of a dynamic earphone with adjustable closed space size, using the dynamic earphone, comprises the following steps:

[0024] Step 1: Obtain acoustic simulation parameters of wood, wherein the acoustic parameters at least include Young's modulus, density, and resonance frequency;

[0025] Step 2: Model the earpiece of the dynamic earphone using COMSOL Multiphysics. The components inside the earpiece include the soundproof cover module, dynamic unit, space adjustment unit, and wooden shell. Set the material of each component and set the simulation parameters of each component.

[0026] Step 3: Generate multiple holes randomly on the sound insulation board using a random function. Set the hole positions and diameters to be random. The hole diameters are between 3 and 8 mm, and the number of holes is between 50 and 100.

[0027] Repeat the random generation m times to obtain a total of m random sound insulation panels;

[0028] Step 4: Select two sound insulation panels from the m sound insulation panels and substitute them into the earpiece model obtained in step 2. The two sound insulation panels can be different or the same.

[0029] COMSOL Multiphysics was used to perform finite element simulations of the acoustic vibrations within the earpiece echo chamber. The vibration source was set at the dynamic unit. During the simulation, the sound insulation board was continuously rotated and the relative positions of the two sound insulation boards were changed. This allowed the variation in the vibration spectrum collected from the sound insulation cover when the sound insulation boards were in different positions to be determined. An angle-spectrum correlation matrix was obtained. The matrix elements included the rotation angle of the first sound insulation board relative to its initial position, the rotation angle of the second sound insulation board relative to its initial position, and the variation in the vibration spectrum collected from the sound insulation cover relative to when both the first and second sound insulation boards were in their initial positions.

[0030] Step 5: Repeat step 4 multiple times, selecting a different sound insulation board combination each time, until all sound insulation board combinations are simulated, and perform m2 times in total; extract the angle-spectrum correlation matrix obtained from each simulation, and select the sound insulation board combination with the largest spectrum variation range in the angle-spectrum correlation matrix;

[0031] Step 6: Process the earpiece using the sound insulation board combination selected in Step 5. After processing, test the earpiece using an acoustic spectrum analyzer to obtain the actual frequency response curve of the processed earpiece. Adjust the angle of the sound insulation board based on the angle-spectrum correlation matrix corresponding to the sound insulation board combination, and then measure the frequency response curve again until it is closest to the Harman target curve.

[0032] The value of m is greater than 500, which means that at least 500 random sound insulation panels are randomly generated;

[0033] Steps 1 to 5 are performed only once for each wood shell made of different wood. Since it is impossible for each piece of wood to be exactly the same, step 6 is adjusted individually for each earpiece to ensure that all earpieces conform to the Harman curve to the greatest extent possible.

[0034] Steps 1 to 5 are performed once for each wood type combination of wooden shell and sound insulation board, that is, 49 times in total for 7 types of wood; because it is impossible for each piece of actual wood to be exactly the same, step 6 is adjusted separately for each earpiece to ensure that all earpieces conform to the Harman curve to the greatest extent possible.

[0035] The beneficial effects of the present invention are:

[0036] This invention designs a new dynamic earphone structure, using tonewood (musical wood) to form the outer shell of the wooden structure. The inner shell forms an enclosed space, and the spatial structure forms an echo chamber, thereby achieving spectrum and vibration suppression, making the earphone sound more balanced and natural, and improving the sound quality.

[0037] The present invention forms a closed space between the interior of the wooden shell and the dynamic coil unit, the closed space forms an echo chamber, and the size of the closed space between the dynamic coil unit and the wooden shell that actually participates in the echo is adjusted by the space adjustment unit.

[0038] A rotating sound insulation board and a water drop-curved wooden shell are provided so that when the two sound insulation boards rotate as a whole, they can move relative to the wooden shell, thereby finely adjusting the frequency response curve of the echo chamber; when the two sound insulation boards rotate relative to each other, the frequency response curve of the echo chamber can be adjusted over a large range.

[0039] A new sound insulation panel screening method and EQ adjustment method have been designed, which can adjust the frequency response curve of the headphones in a wider range and more delicately, thereby improving the sound quality and enhancing the listening experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Attachment Figure 1 This is a schematic diagram of the appearance of the earphone of the present invention;

[0042] Attachment Figure 2 This is an exploded view of the main structure of the earphone receiver of the present invention.

[0043] Attachment Figure 3 This is a schematic structural diagram of the sound insulation board of the present invention;

[0044] Attachment Figure 4 This is a cross-sectional view of the inner surface of the wooden shell of the present invention. DETAILED DESCRIPTION

[0045] Example 1:

[0046] See also Figure 1-4 The present invention provides a closed space size adjustable dynamic earphone, including an earpiece 2 and a headband 1.

[0047] The earphones are head-mounted dynamic earphones, and the number of earphones 2 is two, and the two earphones 2 are connected by a headband 1;

[0048] The handset 2 includes a soundproof cover module 3, a dynamic unit 4, a space adjustment unit 5 and a wooden shell 6;

[0049] A closed space is formed between the interior of the wooden shell 6 and the dynamic unit 4 , and the closed space forms an echo chamber. The size of the closed space between the dynamic unit 4 and the wooden shell 6 that actually participates in the echo is adjusted by the space adjustment unit 5 .

[0050] The material of the wooden housing 6 is beech, rosewood, maple, alder, swamp ash, basswood or mahogany. These woods are all musical instrument woods (tone woods), which have an improved effect on the sound quality of the headphones. Moreover, these woods are relatively hard, making the headphones more stable.

[0051] A sponge cover is provided on one side of the sound insulation cover module 3, and the sponge cover is annular; a dynamic unit 4 is installed on the other side of the sound insulation cover module 3; the diameter of the dynamic unit 4 is smaller than the diameter of the sound insulation cover module 3; the edge of the wooden shell 6 is installed in contact with the edge of the sound insulation cover module 3;

[0052] The sound emission direction of the dynamic unit 4 is toward the annular center of the sponge cover on the sound insulation cover module 3; a space adjustment unit 5 is provided between the dynamic unit 4 and the wooden shell 6.

[0053] like Figure 3 As shown, the space adjustment unit 5 includes two sound insulation boards 51 arranged in front and back. The sound insulation boards 51 are parabolic and made of wood. The sound insulation boards 51 divide the wooden shell 6 and the dynamic unit 4 into two parts. Holes 52 are distributed on the sound insulation boards 51.

[0054] The apex positions of the front and rear sound insulation boards 51 are connected by a rotating shaft 53. A rotation drive device is set at the edges of the two sound insulation boards 51 so that the sound insulation boards 51 can rotate around the axis. The holes 52 on the two sound insulation boards 51 have different distribution sizes and positions. During rotation, different holes 52 are connected, so that the space between the dynamic unit 4 and the wooden shell 6 is connected through multiple connected holes 52.

[0055] The material of the sound insulation board 51 is different from that of the wooden housing 6 , and the density of the material of the sound insulation board 51 is lower than that of the wooden housing 6 .

[0056] An annular frame 54 is provided at the edge of the sound insulation board 51. The outer surface of the annular frame 54 is rack-shaped. The rotation driving device is a plurality of motor-driven gears 55 arranged around the annular frame; the motor is fixedly set on the wooden shell 6, and at least three gears fix the annular frame. The gears 55 rotate to drive the annular frame to rotate; each sound insulation board 51 is driven by an independent gear 55, so that the sound insulation board 51 can rotate relative to each other.

[0057] See also Figure 4 :

[0058] The shape of the hollowed-out inner surface of the wooden shell 6 is as follows:

[0059] The straight line where the axis of the dynamic unit 4 is located is the X-axis, and the vertical direction in the plane where the wooden shell 6 and the soundproof cover are located is the Y-axis; the intersection line of the inner surface of the wooden shell 6 in the XY plane conforms to the equation:

[0060] [(qy+r) 2 +(px) 2 ] 2 -2(qy+r)[(qy+r) 2 +(px) 2 ]+3(px) 2 =0;

[0061] Where p, q, and r are non-zero constant coefficients, and the above equation is named curve I;

[0062] The inner surface of the wooden shell 6 conforms to the curved surface formed by rotating the curve I around the Y axis, that is, a teardrop-shaped curved surface.

[0063] A rotating sound insulation board and a water drop-curved wooden shell are provided so that when the two sound insulation boards rotate as a whole, they can move relative to the wooden shell, thereby finely adjusting the frequency response curve of the echo chamber; when the two sound insulation boards rotate relative to each other, the frequency response curve of the echo chamber can be adjusted over a large range.

[0064] Example 2:

[0065] A method for adjusting EQ of a dynamic earphone with adjustable closed space size, using the dynamic earphone, comprises the following steps:

[0066] Step 1: Obtain acoustic simulation parameters of wood, wherein the acoustic parameters at least include Young's modulus, density, and resonance frequency;

[0067] Step 2: Model the earpiece 2 of the dynamic earphone using COMSOL Multiphysics. The components within the earpiece 2 include the soundproofing module 3, the dynamic unit 4, the spatial adjustment unit 5, and the wooden shell 6. Set the material and simulation parameters for each component.

[0068] Step 3: randomly generate multiple holes 52 on the sound insulation board 51 using a random function, set the positions of the holes 52 to be random and the diameters of the holes 52 to be random, wherein the diameter of the holes 52 is 3-8 mm and the number of the holes 52 is 50-100;

[0069] Repeat the random generation m times to obtain m random sound insulation panels 51;

[0070] Step 4: Select two sound insulation panels 51 from the m sound insulation panels 51 and substitute them into the earpiece 2 model obtained in step 2. The two sound insulation panels 51 may be different or the same sound insulation panels 51.

[0071] Finite element simulation of the acoustic vibrations within the echo chamber of earpiece 2 was performed using COMSOL Multiphysics. The vibration source was set at dynamic unit 4. During the simulation, the sound insulation board 51 was continuously rotated and the relative positions of the two sound insulation boards 51 were changed, thereby obtaining the changes in the vibration spectrum collected from the sound insulation cover when the sound insulation board 51 was in different positions. An angle-spectrum correlation matrix was obtained; the matrix elements included the rotation angle of the first sound insulation board 51 relative to the initial position, the rotation angle of the second sound insulation board 51 relative to the initial position, and the changes in the vibration spectrum collected from the sound insulation cover relative to when both the first sound insulation board 51 and the second sound insulation board 51 were in their initial positions.

[0072] Step 5: Repeat step 4 multiple times, selecting a different combination of sound insulation panels 51 each time, until all combinations of sound insulation panels 51 are simulated, for a total of m2 times; extract the angle-spectrum correlation matrix obtained from each simulation, and select the sound insulation panel 51 combination with the largest spectrum variation range in the angle-spectrum correlation matrix;

[0073] Step 6: Process the earpiece 2 using the combination of sound insulation panels 51 selected in Step 5. After processing, test the earpiece 2 using an acoustic spectrum analyzer to obtain the frequency response curve of the actual processed earpiece 2. Adjust the angle of the sound insulation panels 51 based on the angle-spectrum correlation matrix corresponding to the combination of sound insulation panels 51. Simultaneously, measure the frequency response curve again and adjust it until it is closest to the Harman target curve.

[0074] Example 3:

[0075] The value of m is greater than 500, which means that at least 500 random sound insulation panels 51 are randomly generated;

[0076] Step 1 to step 5 are only performed once for each wooden shell 6 made of different wood; since each piece of actual wood cannot be exactly the same, step 6 is adjusted separately for each earpiece 2 to ensure that all earpieces 2 conform to the Harman curve to the greatest extent.

[0077] Example 4:

[0078] Step 5 of step 1 is performed once for each combination of wooden shell 6 and sound insulation board 51 of wood, that is, 7 types of wood, and is performed 49 times in total; since it is impossible for each piece of actual wood to be exactly the same, step 6 is adjusted separately for each earpiece 2 to ensure that all earpieces 2 conform to the Harman curve to the greatest extent.

[0079] Thus far, the description of the above-described embodiments has been provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present disclosure. The individual elements or features of a particular embodiment are generally not limited to the particular embodiment, but when applicable, they can be interchanged and used for selected embodiments even if not specifically shown or described. In many aspects, the same elements or features can also be changed. Such changes are not considered to depart from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

[0080] Example embodiments are provided so that the present disclosure will be thorough and will fully convey the scope to those skilled in the art. In order to thoroughly understand the embodiments of the present disclosure, numerous details are set forth, such as examples of specific parts, devices, and methods. It will be apparent to those skilled in the art that specific details need not be used, and the example embodiments may be implemented in many different forms, and neither should be construed as limiting the scope of the present disclosure. In certain example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0081] Here, professional vocabulary is used only for the purpose of describing specific example embodiments and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a" and "the" used herein may be intended to include the plural forms as well. The terms "including" and "having" are inclusive and therefore specify the presence of the claimed features, wholes, steps, operations, elements and / or components, but do not exclude the presence or additional presence of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof. Unless the order of execution is explicitly indicated, the method steps, processes and operations described herein are not to be interpreted as necessarily needing to be performed in the specific order discussed and shown. It should also be understood that additional or optional steps may be adopted.

Claims

1. A method for adjusting EQ of a closed-space size-adjustable dynamic earphone, using the closed-space size-adjustable dynamic earphone, the earphone comprising an earpiece (2) and a headband (1), characterized in that: The earphones are head-mounted dynamic earphones, and the number of earphones (2) is two, and the two earphones (2) are connected through the head beam (1); The earpiece (2) includes a soundproof cover module (3), a dynamic unit (4), a space adjustment unit (5) and a wooden shell (6); A closed space is formed between the interior of the wooden housing (6) and the dynamic coil unit (4), the closed space forming an echo chamber, and the size of the closed space between the dynamic coil unit (4) and the wooden housing (6) that actually participates in the echo is adjusted by the space adjustment unit (5); The adjustment method includes the following steps: Step 1: Obtain acoustic simulation parameters of wood, wherein the acoustic parameters at least include Young's modulus, density, and resonance frequency; Step 2: Model the earpiece (2) of the dynamic earphone using COMSOL Multiphysics. The components in the earpiece (2) include a soundproof cover module (3), a dynamic unit (4), a space adjustment unit (5), and a wooden shell (6). Set the material of each component and set the simulation parameters of each component. Step 3: randomly generate a plurality of holes (52) on the sound insulation board (51) through a random function, set the positions of the holes (52) to be random, and the diameters of the holes (52) to be random, wherein the diameters of the holes (52) are between 3 and 8 mm, and the number of the holes (52) is between 50 and 100; Repeat the random generation m times to obtain a total of m random sound insulation panels (51); Step 4: Select two of the m sound insulation panels (51) and substitute them into the earpiece (2) model obtained in step 2. The two sound insulation panels (51) are different or the same sound insulation panels (51); The acoustic vibration in the echo chamber of the earpiece (2) is simulated by finite element method using COMSOL Multiphysics; the vibration source is set at the dynamic coil unit (4); the sound insulation board (51) is continuously rotated and the relative positions of the two sound insulation boards (51) are changed during the simulation process, so as to obtain the variation of the vibration spectrum collected from the position of the sound insulation cover when the sound insulation board (51) is in different positions; an angle-spectrum correlation matrix is ​​obtained; the matrix elements include the rotation angle of the first sound insulation board (51) relative to the initial position, the rotation angle of the second sound insulation board (51) relative to the initial position, and the variation of the vibration spectrum collected from the position of the sound insulation cover relative to when both the first sound insulation board (51) and the second sound insulation board (51) are in the initial positions; Step 5: Repeat step 4 multiple times, selecting a different combination of sound insulation panels (51) each time, until all combinations of sound insulation panels (51) are simulated, and execute m times in total. 2 times; extracting the angle-spectrum correlation matrix obtained from each simulation, and screening out the combination of sound insulation boards (51) with the largest spectrum variation range in the angle-spectrum correlation matrix; Step 6. Process the earpiece (2) by combining the sound insulation board (51) selected in step 5. After processing, test the earpiece (2) using an acoustic spectrum analyzer to obtain the frequency response curve of the actual processed earpiece (2). Adjust the angle of the sound insulation board (51) according to the angle-spectrum correlation matrix corresponding to the combination of the sound insulation board (51). At the same time, measure the frequency response curve again and adjust the frequency response curve to be closest to the Harman target curve.

2. The EQ adjustment method for a closed-space size-adjustable dynamic earphone according to claim 1, characterized in that: The material of the wooden shell (6) is beech, rosewood, maple, alder, swamp ash, basswood or mahogany.

3. The EQ adjustment method for a closed-space size-adjustable dynamic earphone according to claim 1, characterized in that: A sponge cover is provided on one side of the sound insulation cover module (3), and the sponge cover is annular; a dynamic unit (4) is installed on the other side of the sound insulation cover module (3); the diameter of the dynamic unit (4) is smaller than the diameter of the sound insulation cover module (3); the edge of the wooden shell (6) is installed in contact with the edge of the sound insulation cover module (3); The sound emission direction of the dynamic unit (4) is toward the annular center of the sponge cover on the sound insulation cover module (3); and a space adjustment unit (5) is provided between the dynamic unit (4) and the wooden housing (6).

4. The EQ adjustment method for a closed-space size-adjustable dynamic earphone according to claim 3, characterized in that: The space adjustment unit (5) includes two sound insulation boards (51) arranged in front and back, the sound insulation boards (51) are parabolic and made of wood; the sound insulation boards (51) divide the wooden shell (6) and the dynamic coil unit (4) into two parts, and holes (52) are distributed on the sound insulation boards (51); The apex positions of the front and rear sound insulation boards (51) are connected by a rotating shaft (53), and a rotation drive device is provided at the edges of the two sound insulation boards (51) so that the sound insulation boards (51) can rotate around the axis. The holes (52) on the two sound insulation boards (51) have different distribution sizes and positions. When rotating, different holes (52) are connected, so that the space between the dynamic coil unit (4) and the wooden shell (6) is connected through multiple connected holes (52).

5. The EQ adjustment method for a closed-space size-adjustable dynamic earphone according to claim 4, characterized in that: The material of the sound insulation board (51) is different from the material of the wooden shell (6), and the material density of the sound insulation board (51) is lower than that of the wooden shell (6).

6. The EQ adjustment method for a closed-space size-adjustable dynamic earphone according to claim 4, characterized in that: An annular frame (54) is provided at the edge of the sound insulation board (51), the outer surface of the annular frame (54) is in the shape of a rack, and the rotation driving device is a plurality of motor-driven gears (55) arranged around the annular frame; the motor is fixedly arranged on the wooden housing (6), at least three gears fix the annular frame, and the gears (55) rotate to drive the annular frame to rotate; each sound insulation board (51) is driven by an independent gear (55), so that the sound insulation board (51) can rotate relative to each other.

7. The EQ adjustment method for a closed-space size-adjustable dynamic earphone according to claim 4, characterized in that: The shape of the hollowed-out inner surface of the wooden shell (6) is as follows: The straight line where the axis of the dynamic coil unit (4) is located is the X-axis, and the vertical direction in the plane where the contact surface of the wooden shell (6) and the soundproof cover is located is the Y-axis; the intersection line of the inner surface of the wooden shell (6) in the XY plane conforms to the equation: [(qy+r) 2 + (px) 2 ] 2 - 2(qy+r)[(qy+r) 2 + (px) 2 ]+3 (px) 2 =0; Where p, q, and r are non-zero constant coefficients, and the above equation is named curve I; The inner surface of the wooden shell (6) conforms to the surface formed by rotating the curve I around the Y axis, that is, a teardrop-shaped surface.

8. The EQ adjustment method for a closed-space size-adjustable dynamic earphone according to claim 1, characterized in that: The value of m is greater than 500, which means that at least 500 random sound insulation panels (51) are randomly generated; Steps 1 to 5 are performed only once for each wooden shell (6) made of different wood. Since it is impossible for each piece of wood to be exactly the same, step 6 is adjusted individually for each earpiece (2) to ensure that all earpieces (2) conform to the Harman curve to the greatest extent possible.

9. The EQ adjustment method for a closed-space size-adjustable dynamic earphone according to claim 1, characterized in that: Steps 1 to 5 are performed once for each combination of the wooden shell (6) and the sound insulation board (51) of each wood, that is, 7 types of wood, and performed 49 times in total; since it is impossible for each piece of actual wood to be exactly the same, step 6 is adjusted individually for each earpiece (2) to ensure that all earpieces (2) conform to the Harman curve to the greatest extent possible.

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