A coaxial loudspeaker with a horn and a shape optimization method thereof

Abstract

The application discloses a coaxial loudspeaker with a horn and a shape optimization method thereof. The coaxial loudspeaker comprises a bass loudspeaker, a treble loudspeaker, and a horn with an inner cavity and open at both upper and lower ends. The treble loudspeaker comprises a treble cone, the horn surrounds the treble cone, the lower end of the horn is connected to the treble loudspeaker, and the upper end of the horn is the largest inner diameter part. The shape optimization method comprises the following steps: S1, establishing a geometric model of the coaxial loudspeaker as claimed in claim 1 to obtain a control node in a profile curve of the horn; S2, setting a physical field; S3, defining material parameters; S4, meshing; S5, optimizing geometric parameters of the profile shape of the horn; and S6, drawing an optimized geometric model of the horn according to the optimized parameters. The application can have a better frequency response curve when the treble loudspeaker works, and can quickly and accurately optimize the shape of the horn to improve the acoustic performance of the loudspeaker.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of loudspeakers, in particular to a coaxial loudspeaker with a horn and a shape optimization method thereof. BACKGROUND

[0002] A coaxial loudspeaker integrates a tweeter and a woofer, which are responsible for playing back high pitch and low pitch respectively. The advantage is that the frequency bandwidth of the single loudspeaker is greatly improved, and it is widely used in car audio. Currently, in a few high-quality loudspeaker audio systems, sometimes only the tweeter of the coaxial loudspeaker is used without the woofer, which is used to adjust the sound field in the car. This also leads to the fact that when the tweeter works alone, it also needs to have a good frequency response curve. However, in the coaxial loudspeaker, the structure of the woofer will inevitably affect the radiation sound field of the tweeter. SUMMARY

[0003] In view of the above problems, the present application provides a coaxial loudspeaker with a horn, which can have a better frequency response curve when the tweeter works, and at the same time does not affect the sound field radiation of the woofer. The present application also provides a shape optimization method of the coaxial loudspeaker with a horn, which can quickly and accurately optimize the shape of the horn and improve the acoustic performance of the loudspeaker.

[0004] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0005] A coaxial loudspeaker with a horn, comprising a woofer and a tweeter, the coaxial loudspeaker further comprising a horn having an inner cavity and being open at both upper and lower ends, the tweeter comprising a tweeter cone, the horn surrounding the tweeter cone, the lower end of the horn being connected to the tweeter, and the upper end of the horn being the largest inner diameter thereof.

[0006] In a preferred embodiment, the horn has an expanding portion, the inner diameter of the expanding portion gradually increasing from bottom to top. More preferably, the cross section of the horn along the up-down direction has an inner contour in the shape of two mirror-symmetric Bezier curves. This makes the frequency response curve of high frequency relatively smooth.

[0007] In a preferred embodiment, the inner diameter of the horn gradually increases from bottom to top. More preferably, the cross section of the horn along the up-down direction has an inner contour in the shape of two mirror-symmetric Bezier curves. This makes the frequency response curve of high frequency relatively smooth.

[0008] Preferably, the tweeter further comprises a seat, the seat being arranged on the woofer, the tweeter cone being arranged on the seat, and the lower end of the horn being connected to the outer peripheral edge of the seat and / or the tweeter cone.

[0009] More preferably, the lower end surface of the horn has a local part with an upward arch, and the edge part of the high-frequency cone is located below the arch and forms an annular cavity between the two, which is in communication with the inner cavity. This makes the frequency response curve of high frequencies relatively smooth.

[0010] More preferably, the high-frequency speaker further comprises a soldering piece for transmitting audio signals to the high-frequency voice coil, the upper part of the soldering piece is embedded in the seat and is in conduction with the input end of the high-frequency voice coil, and the lower part of the soldering piece extends into the bass speaker to be in conduction with the signal input line.

[0011] Further, the bass speaker comprises a magnetic circuit system, and a through hole extending in the up-down direction is formed in the magnetic circuit system, the signal input line penetrates into the through hole, and the lower part of the soldering piece extends into the through hole to be in conduction with the signal input line.

[0012] Preferably, the coaxial speaker further comprises a dustproof ring connected between the horn and the bass speaker.

[0013] More preferably, the bass speaker comprises a bass cone, the dustproof ring is connected between the horn and the bass cone, and the dustproof ring is made of a breathable material. It is used for dustproof of the magnetic gap of the bass speaker.

[0014] Further, the cross section of the dustproof ring in the up-down direction comprises two mirror-symmetrical wavy shapes or zigzag shapes to avoid pulling the bass cone when the bass speaker works.

[0015] Further, the breathable material is cotton, PC (polycarbonate) or CONEX (aramid fiber). The dustproof ring is only used for dustproof, not for waterproof.

[0016] Preferably, the bass speaker comprises a bass voice coil, the high-frequency speaker is arranged in the bass voice coil, and the uppermost end of the bass speaker and the upper end of the horn are both lower than the upper end of the bass speaker. The high-frequency speaker and the horn are located in the bass speaker as a whole.

[0017] Preferably, the coaxial speaker further comprises a plurality of extension fins extending inward from the inner surface of the horn, and the extension fins are located above the high-frequency cone of the high-frequency speaker. More preferably, the extension fins extend inward in the radial direction of the horn. Further, the size of the extension fins in the radial direction gradually increases from top to bottom. Still further, the lower end of each of the extension fins is connected to an annular part. Still further, the inner edge of the extension fins is arc-shaped. The extension fins can effectively protect the internal components of the high-frequency speaker, prevent foreign objects such as fingers from entering the high-frequency speaker and damaging the internal components such as the high-frequency cone, and make the high-frequency diffusion better.

[0018] The present invention also adopts the following technical solution:

[0019] A method for optimizing the shape of a coaxial loudspeaker with a horn includes the following steps:

[0020] S1. Establish the geometric model of the coaxial loudspeaker as described above, and obtain the control nodes in the horn's contour curve;

[0021] S2, Set up the physical field;

[0022] S3, Define material parameters;

[0023] S4, Mesh generation;

[0024] S5. Optimize the geometric parameters of the horn's outline shape; and

[0025] S6. Draw the optimized geometric model of the horn based on the optimized parameters;

[0026] Specifically, step S5 includes:

[0027] S51. Select optimization parameters: Use the coordinate values ​​P of a set of control nodes in the horn's contour curve as optimization parameters.

[0028] S52. Set constraints: Limit the range C of coordinate value P to:

[0029] C = {P: lb ≤ P ≤ ub}

[0030] In the above formula, lb is the lower limit of the coordinate value P, and ub is the upper limit of the coordinate value P.

[0031] S53. Determine the optimization objective: the high-frequency average sound pressure level response of the coaxial loudspeaker at 0° axial and off-axis angles θ. and The sum should be the maximum value, that is, satisfy:

[0032]

[0033] In the above formula, It is a set of optimization parameters that satisfy the optimization objective; It is an operator for finding the maximum value;

[0034] S54. Optimization Calculation: Based on the optimization parameters P and constraints C, the optimization algorithm is used to calculate the result that satisfies the optimization objective. A set of optimization parameters

[0035] Preferably, step S2 specifically includes:

[0036] S21, electromagnetic field and vibration system: setting a "fixed constraint" on the fixed part of the speaker vibration system component; setting the material constitutive relation of the speaker vibration system component as a "linear elastic material model"; setting an axial load FF on the speaker voice coil, as follows:

[0037]

[0038] In the above formula, BL is the driving force coefficient of the speaker magnetic circuit, Zb(freq) is the basic impedance frequency response curve of the speaker magnetic circuit, v is the axial vibration speed of the speaker voice coil, and V0 is the speaker loading voltage;

[0039] S22, sound field: setting the geometric model of the horn profile as a "hard sound field boundary"; setting the outer layer of the air domain around the speaker as a "perfectly matched layer".

[0040] In step S1, a geometric model of the speaker and its surrounding air domain is established in the finite element analysis software, and a geometric model of the horn profile is established in a parametric Bezier curve, control nodes in the curve are obtained, and the geometric shape of the horn profile is controlled by the coordinate values of the control nodes.

[0041] In step S3, the mechanical material parameters of each component of the speaker vibration system are defined; the material parameters of the air are defined.

[0042] In step S4, the grid of the speaker and its surrounding air domain is divided into "free triangular grid" elements, and the maximum grid element size should meet the principle that there are at least 5-6 linear elements within one wavelength of sound.

[0043] In step S54, the optimization algorithm is selected from seven non-gradient optimization algorithms, including Nelder-Mead, BOBYQA, COBYLA, Laplace, Winslow, coordinate lookup, and Yeoh smoothing, and three gradient optimization algorithms, including SNOPT, MMA, and Levenberg-Marquardt.

[0044] The above steps are executed in the finite element analysis software, including COMSOL Multiphysics and ANSYS.

[0045] The above scheme is adopted in the present application, which has the following advantages compared with the prior art:

[0046] The coaxial loudspeaker with a horn of the present application, when the tweeter works, the tweeter horn guides the sound wave to propagate to the front, prevents the sound wave from radiating backward, thereby reducing the influence of the woofer on the tweeter, and the gradually outward expanding structure is beneficial to the expansion of the high frequency of the tweeter. The shape optimization method of the present application can quickly, accurately and low-costly optimize the loudspeaker horn by designing the optimal Bezier curve shape of the horn through the optimization algorithm, thereby shortening the research and development cycle of the loudspeaker horn and improving the acoustic performance of the loudspeaker. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the present application, the drawings needed in the following embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0048] Figure 1 It is a schematic diagram of the overall shape of a coaxial loudspeaker according to an embodiment of the present application.

[0049] Figure 2 It is Figure 1 the top view of the coaxial loudspeaker shown in the figure.

[0050] Figure 3 It is Figure 2 the sectional view of A-A in the figure.

[0051] Figure 4 It is Figure 3 the enlarged view of B in the figure.

[0052] Figure 5 It is Figure 2 the three-dimensional schematic diagram of the tweeter and the horn in the figure.

[0053] Figure 6 It is Figure 2 the sectional view of the tweeter and the horn in the figure.

[0054] Figure 7 It is a comparison diagram of the frequency response curves of the coaxial loudspeaker without horn and the coaxial loudspeaker of the present application.

[0055] Figure 8 It is a flow chart of a shape optimization design method according to an embodiment of the present application.

[0056] Figure 9 It is a geometric model of the loudspeaker, the horn and the surrounding air.

[0057] Figure 10 The real part of the basic impedance of the tweeter is shown.

[0058] Figure 11 The imaginary part of the basic impedance of a tweeter is shown;

[0059] Figure 12 The "fixed constraint" boundary is shown;

[0060] Figure 13 The voice coil of a tweeter is shown;

[0061] Figure 14 The diaphragm of a tweeter is shown;

[0062] Figure 15 The "outfield calculation" boundary is shown;

[0063] Figure 16 The "internal hard soundfield boundary (wall)" boundary is shown;

[0064] Figure 17 The "perfectly matched layer" is shown;

[0065] Figure 18 The "structure-acoustic" boundary is shown;

[0066] Figure 19 The "free triangular mesh" region is shown;

[0067] Figure 20 The "mapped" mesh region is shown;

[0068] Figure 21 The meshing result is shown;

[0069] Figure 22 The optimization result of the horn geometry model of a tweeter is shown.

[0070] In the above figures,

[0071] 1. A woofer; 11. Basket; 12. Woofer cone; 13. Woofer voice coil; 14. First magnetic circuit system; 141. T-iron; 142. Magnetic steel; 143. Through hole; 15. Signal input wire; 16. Positioning tab;

[0072] 2. A tweeter; 21. Cavity; 22. Tweeter cone; 221. Center arch; 222. Edge arch; 23. Tweeter voice coil; 24. Second magnetic circuit system; 25. Soldering tab;

[0073] 3. Horn; 31. Arch; 310. Annular cavity; 32. Extended fin; 33. Annular component;

[0074] 4. Dust shield. DETAILED DESCRIPTION

[0075] The preferred embodiments of the present application will be described in detail below with reference to the drawings. It should be noted that the description of the embodiments is for the purpose of helping understand the present application, and is not intended to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0076] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0077] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0078] Embodiment 1

[0079] Referring to Figures 1 to 6 The present embodiment provides a coaxial loudspeaker with a horn, which includes a bass speaker 1 and a tweeter 2 arranged coaxially. The coaxial loudspeaker further includes a horn 3 having an inner cavity and being open at both upper and lower ends. The tweeter 2 includes a tweeter cone 22, and the horn 3 surrounds the tweeter cone 22. The lower end of the horn 3 is connected to the tweeter 2, and the upper end of the horn 3 is the largest in inner diameter. The horn 3 has an expanding portion, and the inner diameter of the expanding portion gradually increases from bottom to top. Further, the inner diameter of the horn 3 gradually increases from bottom to top, and the horn 3 as a whole has a gradually expanding shape. Specifically, the horn 3 has a cross section in the up-down direction, which has an inner contour in the shape of two mirror-symmetrical Bezier curves, so that the frequency response curve of high frequencies is relatively smooth, as shown in Figure 3 In another embodiment, the horn 3 can first expand inwardly and then gradually expand outwardly. The horn 3 significantly reduces the influence of the structure of the bass speaker 1 on the sound field radiated by the tweeter 2. The horn not only can improve the acoustic impedance of the surface of the loudspeaker diaphragm, thereby improving the sensitivity of the loudspeaker, but more importantly, it can widen the directivity of the high-frequency sound field of the loudspeaker, and improve the sound field effect.

[0080] The bass speaker 1 comprises a frame 11, a bass cone 12 and a first magnetic circuit system 14 arranged on the frame 11, a bass voice coil 13 connected to the bass cone 12, and a positioning branch 16 sleeved on the bass voice coil 13. The first magnetic circuit system 14 forms a magnetic gap for the bass voice coil 13 to be inserted into, the lower end of the bass voice coil 13 is inserted into the magnetic gap and vibrates up and down after being electrified, thereby driving the bass cone 12 to vibrate and sound. The outer peripheral edge of the positioning branch 16 is fixed on the frame 11, which is used to prevent the horizontal shaking of the bass voice coil 13.

[0081] The treble speaker 2 is arranged in the voice coil of the bass speaker 1 in general. The uppermost end of the bass speaker 1 and the upper end of the horn 3 are both lower than the upper end of the bass speaker 1, and the treble speaker 2 and the horn 3 are located in the bass speaker 1 as a whole, so that the size of the coaxial speaker and the space occupied thereby are not additionally increased.

[0082] The treble speaker 2 specifically comprises a seat 21 arranged on the bass speaker 1, the above-mentioned treble cone 22 and a second magnetic circuit system 24 arranged on the seat 21, and a treble voice coil 23 connected to the treble cone 22. The second magnetic circuit system 24 forms a magnetic gap for the treble voice coil 23 to be inserted into, the lower end of the treble voice coil 23 is inserted into the magnetic gap and vibrates up and down after being electrified, thereby driving the treble cone 22 to vibrate and sound.

[0083] The seat 21 is specifically arranged on the first magnetic circuit system 14 of the bass speaker 1. The first magnetic circuit system 14 specifically comprises a T-shaped iron 141 and a magnetic steel 142 sleeved on the T-shaped iron 141, the magnetic steel 142 surrounds the T-shaped iron 141 and forms a magnetic gap. The seat 21 is arranged on the upper portion of the T-shaped iron 141. In the embodiment, a through hole 143 extending in the up-down direction is formed in the T-shaped iron 141. The lower portion of the seat 21 is inserted into the through hole 143.

[0084] The treble speaker 2 further comprises a soldering sheet 25 for transmitting an audio signal to the treble voice coil 23. The upper portion of the soldering sheet 25 is embedded in the seat 21 and in conduction with the input end of the treble voice coil 23, and the lower portion of the soldering sheet 25 extends into the bass speaker 1 to be in conduction with the signal input line 15. Specifically, the signal input line 15 penetrates into the through hole 143, and the lower portion of the soldering sheet 25 extends into the through hole 143 to be in conduction with the signal input line 15. The signal input line 15 is also in conduction with the lead wire of the bass voice coil 13, and the audio signal is input to the bass speaker 1.

[0085] In combination Figure 3 And Figure 4As shown, the lower end of the horn 3 is specifically connected to the outer peripheral edge of the cabin 21 and / or the high-pitched sound cup 22. The lower end surface of the horn 3 has a partial (the portion near the inner side) upwardly arched arching portion 31, and the edge portion of the high-pitched sound cup 22 is located below the arching portion 31 and forms an annular recess 310 between the two, which is in communication with the inner cavity, so that the frequency response curve of the high frequency is relatively smooth. Specifically, the high-pitched sound cup 22 includes a centrally upwardly arched arching portion 221 and a peripheral arching portion 222 surrounding the centrally upwardly arched arching portion 221, and the peripheral arching portion 222 is located below the arching portion 31 of the horn 3.

[0086] The coaxial speaker further includes a dustproof ring 4 connected between the horn 3 and the low-pitched sound cup 12. The dustproof ring 4 is specifically connected between the upper end of the horn 3 and the low-pitched sound cup 12. The dustproof ring 4 is made of a breathable material and is used for dustproofing the magnetic gap of the low-pitched sound cup 1. The cross section of the dustproof ring 4 in the up-down direction includes two mirror-symmetrical wavy or zigzag shapes to avoid pulling the low-pitched sound cup 12 when the low-pitched sound cup 1 is working. The breathable material is cotton, PC (polycarbonate) or CONEX (aramid fiber). The dustproof ring 4 is only used for dustproofing and not for waterproofing.

[0087] Further, the coaxial speaker further includes a plurality of extending fins 32 extending inwardly from the inner surface of the horn 3, and the extending fins 32 are located above the high-pitched sound cup 22 of the high-pitched sound cup 2. The extending fins 32 specifically extend inwardly along the radial direction of the horn 3, and the size of the extending fins 32 in the radial direction gradually increases from top to bottom. The lower end of each extending fin 32 is connected to an annular member 33. The inner edge of the extending fin 32 is arc-shaped. The extending fins 32 can effectively protect the internal components of the high-pitched sound cup 2, prevent foreign objects such as fingers from entering the high-pitched sound cup 2 and damaging the internal components such as the high-pitched sound cup 22, and make the high frequency diffusion better.

[0088] The frequency response of a coaxial speaker without a horn (comparative example) and the coaxial speaker with the horn 3 of the present embodiment were tested respectively, and the test results are shown in Figure 7 The coaxial speaker of the comparative example has a structure basically the same as the present embodiment, and the only difference is that the high-pitched sound cup is not provided with a horn, and the dustproof ring is connected between the high-pitched sound cup and the low-pitched sound cup. Figure 7 The thin line in the figure is the frequency response curve of the high-pitched sound cup in the coaxial speaker of the comparative example; the thick line in the figure is the frequency response curve of the high-pitched sound cup in the coaxial speaker of the present embodiment. As can be seen from the figure, the frequency response curve of the high-pitched sound cup in the coaxial speaker of the present embodiment is more balanced.

[0089] Example 2

[0090] The horn geometry of the coaxial loudspeaker directly relates to the sound reproduction quality and sound field directivity of the loudspeaker. If the horn geometry is designed by the traditional empirical method of designing a product, trial-manufacturing a sample, testing, improving the design, trial-manufacturing a sample again, and testing again, horn problems cannot be found until the later stage of the design, and the development cycle is long and the cost is high. The industry has begun to use a numerical simulation analysis method based on finite elements to simulate and analyze the sound field response of the loudspeaker under different horn shapes. Although this method greatly shortens the product development cycle and reduces the research and development cost, it still relies on repeated design, and often the theoretically optimal horn shape cannot be designed. Based on this, the embodiment provides a shape optimization method for the coaxial loudspeaker with a horn of embodiment 1 to solve the following problems: 1) the traditional empirical design method of the loudspeaker horn has the problems of a long development cycle and high cost; 2) it is difficult to design a theoretically optimal horn geometry by relying on the general loudspeaker sound field simulation analysis method.

[0091] The embodiment takes the tweeter unit of the coaxial loudspeaker of embodiment 1 as an example, uses COMSOL Multiphysics 5.5 to optimize the horn shape of the tweeter unit, and directly gives the optimization design result of the horn. Figure 8 is a flowchart of the shape optimization method, mainly including the following steps:

[0092] Step 1: Since the tweeter unit of the coaxial loudspeaker has an axisymmetric structure, in order to facilitate calculation, first select the 2D axisymmetric analysis environment in the COMSOL software, then select the "acoustic-structure interaction, frequency domain" physical field interface, and finally select "frequency domain study" because three-field coupling frequency domain analysis is to be performed;

[0093] Step 2: Use the COMSOL software to establish a 2D axisymmetric geometric model of the tweeter, the surrounding air domain, and the diaphragm of the woofer, and use a parametric cubic Bezier curve to establish a geometric model of the horn profile, as shown by the thick line indicated by the arrow in Figure 9 . The geometric model is explained as follows: 1) the magnetic circuit system of the tweeter does not participate in the finite element calculation, and is only treated as a hard sound field boundary; the driving force coefficient and the basic impedance frequency response curve of the required magnetic circuit system can be obtained by separate simulation analysis or measurement; 2) the diaphragm of the woofer also does not participate in the finite element calculation, and is only treated as a hard sound field boundary; 3) the dark curve represents a cubic Bezier curve, which is the horn profile, and the two end points of the curve are fixed, and the coordinate values of the two middle nodes of the curve are used as optimization parameters;

[0094] Step 3: Define functions, parameters, and variables, including: 1) Define the average function on the voice coil and name it coil av, which is to define the arithmetic average of the counter electromotive force in the voice coil domain; 2) Import the interpolation function of the real part and the imaginary part of the basic impedance of the high-pitched loudspeaker, named Zbr and Zbi respectively, as shown in Figure 10 and as shown in Figure 11 ; 3) Define the coordinate parameters of two nodes in the cubic Bezier curve as (P1r, P1z) and (P2r, P2z), and set their initial coordinates to (13.1, -10) [mm] and (14, -0.5) [mm]; 4) Define six variables as follows:

[0095] Zb: Zbr(freq) + i*Zbi(freq);

[0096] FF: BL*(V0-BL*coil_av(solid.u_tZ)) / Zb;

[0097] Lp_0: 10*log10(0.5*abs(pfar(0,1[m])[Pa])^2 / acpr.pref_SPL^2);

[0098] Lp_the: 10*log10(0.5*abs(pfar(0.707[m],0.707[m])[Pa])^2 / acpr.pref_SPL^2);

[0099] Lp_ave_0: sum(with(ka,Lp_0),ka,1,21) / 21;

[0100] Lp_ave_the: sum(with(ka,Lp_the),ka,1,21) / 21;

[0101] In the above formula, Zb is the base impedance of the tweeter; Zbr(freq) is the real part of the base impedance; Zbi(freq) is the imaginary part of the base impedance; i is the imaginary unit; FF is the load on the voice coil; BL is the force factor of the tweeter, which is 1.71 [Wb / m]; V0 is the loaded voltage of the tweeter, which is 2.828 [V]; solid.u_tZ is the axial vibration velocity expression of the voice coil of the tweeter; Lp_0 is the sound pressure level of the tweeter at 0° axis at 1 meter; abs() is the modulus operator; pfar() is the far-field sound pressure solving operator, which will be defined in the subsequent steps as “far-field calculation”; acpr.pref_SPL is the reference sound pressure, which is 20 micro-Pascal; Lp_the is the sound pressure level of the tweeter at 45° off-axis at 1 meter; Lp_ave_0 is the average sound pressure level of the tweeter at 0° axis at 1 meter; sum() is the summation operator, with() is the sorting operator, and ka is the sequence number; Lp_ave_the is the average sound pressure level of the tweeter at 45° off-axis at 1 meter;

[0102] Step 4: Define the “solid mechanics” physical field interface, including: 1) set “fixed constraint” at the thick line pointed by the arrow in Figure 12 ; 2) set “body load” at the voice coil pointed by the arrow in Figure 13 ; set the load type as “total force”, and input FF in the z-axis direction; 3) set “damping” at the diaphragm pointed by the arrow in Figure 14 ; set the damping type as “isotropic loss factor”;

[0103] Step 5: Define the “pressure acoustics, frequency domain” physical field interface, including: 1) set “external calculation” at the thick line pointed by the arrow in Figure 15 ; 2) set “internal hard sound field boundary (wall)” at the thick line pointed by the arrow in Figure 16 ; 3) set “perfectly matched layer” on the area pointed by the arrow in Figure 17 ;

[0104] Step 6: Define the “acoustic-structure boundary”, as shown by the thick line pointed by the arrow in Figure 18 ;

[0105] Step 7: Set the material parameters, including: 1) the material parameters of air come from the COMSOL material database; 2) the material parameters of the components of the tweeter vibration system are shown in Table 1 below:

[0106] Table 1 Material Parameters

[0107]

[0108] Step 8: Meshing, including: 1) in Figure 19The region indicated by the middle arrow is divided into a "free triangle mesh", and the maximum unit size is set to "343[m] / 20000 / 5". Figure 20 The region indicated by the middle arrow is divided into a "free triangle mesh", and the maximum unit size is set to "343[m] / 20000 / 5".

[0109] Table 2

[0110]

[0111] Step 9: Set the frequency range to 2000Hz-20000Hz, 1 / 6 octave;

[0112] Step 10: Set the optimization, including: 1) Set the optimization algorithm to "Nelder-Mead"; 2) Set the objective function to Lp_ave_0 and Lp_ave_the; 3) The target function type is "maximization"; 4) Set the value range of the optimization parameters, as shown in the table below: Figure 21

[0113] Step 11: Left-click the "Calculate" button, and view the calculation progress in the lower right corner of the software interface;

[0114] Step 12: Read the calculation results of the optimization parameters in the table column in the lower right corner of the software interface: (P1r, P1z) = (13.5, -10); (P1r, P1z) = (16, -1);

[0115] Step 13: Draw the geometry of the high-frequency loudspeaker horn according to the calculation results of the optimization parameters, as shown in the region indicated by the middle arrow. Figure 22

[0116] The above method is suitable for moving-coil electrodynamic loudspeakers, moving-iron loudspeakers and MEMS loudspeakers.

[0117] The above method is based on the three-field coupling simulation analysis technology of loudspeaker magnetic circuit system, vibration system and sound field, and designs the optimal Bezier curve shape of the horn through the optimization algorithm, so that the loudspeaker horn can be quickly, low-cost and accurately optimized, thereby shortening the research and development cycle of the loudspeaker horn and improving the acoustic performance of the loudspeaker.

[0118] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and are a preferred embodiment, the purpose of which is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application.​​

Claims

1. A coaxial loudspeaker having a horn, comprising a woofer and a tweeter, characterized by: The coaxial loudspeaker further comprises a horn having an inner cavity and being open at both upper and lower ends, the tweeter comprises a tweeter cone, the horn surrounds the tweeter cone, the lower end of the horn is connected to the tweeter, and the upper end of the horn is the largest inner diameter part of the horn; the woofer comprises a woofer voice coil, the tweeter is arranged in the woofer voice coil, and the uppermost end of the tweeter and the upper end of the horn are both lower than the upper end of the woofer. The tweeter further comprises a seat arranged on the woofer, the tweeter cone is arranged on the seat, and the lower end of the horn is connected to the outer peripheral edge of the seat and / or the tweeter cone; a part of the lower end surface of the horn has an upwardly arched arching part, the edge part of the tweeter cone is located below the arching part and forms an annular cavity between the arching part and the inner cavity.

2. The coaxial loudspeaker of claim 1, wherein: The horn has an expanding part, and the inner diameter of the expanding part gradually increases from bottom to top; or the inner diameter of the horn gradually increases from bottom to top.

3. The coaxial loudspeaker of claim 1, wherein: The tweeter further comprises a soldering lug for transmitting an audio signal to the tweeter voice coil, the upper part of the soldering lug is embedded in the seat and in conduction with the input end of the tweeter voice coil, the woofer comprises a magnetic circuit system, the magnetic circuit system is provided with a through hole extending in the upward and downward directions, a signal input line is inserted into the through hole, and the lower part of the soldering lug is inserted into the through hole and in conduction with the signal input line.

4. The coaxial loudspeaker of claim 1, wherein: The coaxial loudspeaker further comprises a dustproof ring connected between the horn and the woofer.

5. The coaxial loudspeaker of claim 1, wherein: The coaxial loudspeaker further comprises a plurality of extension fins extending inward from the inner surface of the horn, and the extension fins are located above the tweeter cone of the tweeter.

6. A method of shape optimization of a coaxial loudspeaker with a horn, characterized in that, The method comprises the following steps: S1, establishing a geometric model of the coaxial loudspeaker as claimed in claim 1 to obtain control nodes in the profile curve of the horn; S2, setting a physical field; S3, defining material parameters; S4, meshing; S5, optimizing the geometric parameters of the profile shape of the horn; and S6, drawing an optimized geometric model of the horn according to the optimized parameters; wherein the step S5 specifically comprises: S51, selecting optimization parameters: taking the coordinate values P of a group of control nodes in the profile curve of the horn as the optimization parameters; S52, setting a constraint condition: limiting the value range C of the coordinate values P as follows: C={P: lb≤P≤ub} in the formula, lb is the lower limit of the value of the coordinate value P, and ub is the upper limit of the value of the coordinate value P; S53, determining optimization target: high frequency average sound pressure level response of 0° axial and off-axis θ angle of coaxial speaker and The sum should take the maximum value, i.e. satisfy: In the above formula, is a set of optimization parameters that satisfy an optimization objective; is an operator that solves the maximum value; S54, optimization calculation: according to the optimization parameters P and the constraint conditions C, an optimization algorithm is used to calculate a set of optimization parameters P satisfying the optimization target ​ 7. The shape optimization method of claim 6, wherein the step S2 specifically comprises: S21, electromagnetic field and vibration system: setting a "fixed constraint" on the fixed part of the loudspeaker vibration system component; setting the material constitutive relation of the loudspeaker vibration system component as a "linear elastic material model"; setting an axial load FF on the loudspeaker voice coil as follows: in the formula, BL is the driving force coefficient of the loudspeaker magnetic circuit, Zb(freq) is the basic impedance frequency response curve of the loudspeaker magnetic circuit, v is the axial vibration speed of the loudspeaker voice coil, and V0 is the loaded voltage of the loudspeaker; S22, sound field: setting the geometric model of the horn profile as a "hard sound field boundary"; setting the outer layer of the air domain around the loudspeaker as a "perfectly matched layer".

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