A phase plug for sound amplification and a method for designing and manufacturing the same

Abstract

The application discloses a phase plug for sound amplification, which comprises two or more annular sound wave channels, the cross section of the sound wave channels is exponential, the area ratio of the input and output of each sound wave channel is the same, equal transmission ratio characteristics are formed, the analog sound paths of the sound waves in each sound wave channel are equal, and equal phase characteristics are formed. By adopting the above technical scheme, the exponential sound wave channel is adopted, the distortion in the sound wave transmission process is reduced, the equal transmission ratio characteristics are adopted, the equal effective wave fronts with the same transmission efficiency are formed at the outlet after the sound waves pass through each sound wave channel of the phase plug, the equal phase characteristics are adopted, and the full effective coupling superposition of the sound waves output by the sound wave channels is realized. In addition, the application further discloses a design and manufacturing method of the phase plug.

Description

Technical Field

[0001] This invention relates to the field of loudspeaker equipment, and in particular to a phase plug for loudspeaker amplification and its design and manufacturing method. Background Technology

[0002] In professional sound reinforcement applications, horn structures are typically used to increase sound pressure level (SPL, the acoustic unit of volume) (see figure). Horns increase the radiation resistance of the driver's front load, significantly improving sound reinforcement efficiency and boosting the SPL. However, this often causes acoustic interference, leading to distortion and a significant reduction in sound quality.

[0003] To address this issue, a common approach is to add a phase plug structure to reduce acoustic interference within the horn and improve sound quality.

[0004] Based on the known theories of horn loudspeakers, we can summarize horn loudspeaker design technology as: one center and three basic points.

[0005] One key focus is reducing total distortion (THD). Distortion directly damages the sound quality of the amplified sound, affecting its effectiveness.

[0006] These three basic points can also be understood as three directions for optimized design. For example... Figure 1 As shown,

[0007] 1. Sound reinforcement efficiency – depends on the compression ratio of the horn, usually expressed as the area ratio of the diaphragm to the throat: Sdiaphragm / Sthroat

[0008] 2. Lower cutoff frequency f 下 ——f 下 It mainly depends on the horn length (L). However, an excessively long L will increase the total distortion (THD) and result in an excessively large size, making transportation difficult. Therefore, f 下 The space for optimization is limited.

[0009] 3. Effective replay upper limit frequency f 上 ——f 下 ~f 上 The effective operating bandwidth of a horn loudspeaker. 上 It depends on the structure of the phase plug. 上 The higher the value, the wider the effective working bandwidth. Therefore, f 上 This will be the main focus of the horn optimization design.

[0010] Existing phase plugs have the following problems:

[0011] First, the phase plug uses an external pressure type. While this structure can improve mid-frequency interference, it cannot solve the high-frequency extension problem of the mid-frequency driver, resulting in a narrower bandwidth for the horn mid-frequency and a limited usable frequency range. This range is typically 300Hz-1.5kHz. Additionally, when the mid-frequency diaphragm vibrates up and down under the dust cap, the air in the front cavity is compressed and released, creating an "air cushion" effect. This affects the diaphragm's vibration characteristics, causing nonlinear vibration and resulting in nonlinear distortion. Furthermore, high sound pressure levels are often required in sound reinforcement applications to extend sound transmission distance and expand coverage. This leads to increased input power, and consequently, increased power handling by the mid-frequency unit. This causes the voice coil temperature to rise rapidly; if heat dissipation is not effective, the voice coil will overheat and burn out.

[0012] Second, the acoustic wave channel adopts parallel tube type, linear type, parabolic type, etc., resulting in high transmission distortion.

[0013] Third, the ratio of the input port area to the output port area of ​​each sound wave channel is different, which prevents each channel from achieving equal-efficiency transmission.

[0014] Fourth, the propagation time of sound waves in each sound wave channel is different, that is, two or more sound waves cannot be triggered or arrive at the same time, and the full coupling and superposition of sound waves cannot be achieved. Due to the phase difference, local interference or cancellation occurs.

[0015] In conclusion, improvements are needed. Summary of the Invention

[0016] The purpose of this invention is to provide a phase plug for sound reinforcement that can effectively solve the above-mentioned problems, and its design and manufacturing method. To achieve the above objective, this invention adopts the following technical solution:

[0017] A phase plug for sound reinforcement includes two or more annular sound wave channels, the cross-section of the sound wave channels is an exponential cross-section, the ratio of the area of ​​the input port to the area of ​​the output port of each sound wave channel is the same, and the phase of the sound wave in each sound wave channel is equal.

[0018] Using the above technical solution, the cross-section of the acoustic channel is exponential. Sound waves propagate and diffuse along the exponential channel, resulting in the lowest transmission distortion compared to parallel, linear, or parabolic channels. The ratio of the area of ​​the input to the output of each acoustic channel is the same, creating an equal transmission ratio characteristic. This ensures that after passing through each acoustic channel, the sound waves form an equivalent wavefront with the same transmission efficiency at the exit. The phase of the sound waves in each acoustic channel is equal, meaning the simulated sound paths are equal. Since the speed of sound is constant, achieving equal phase, i.e., equal simulated sound paths, requires equal sound wave transmission times, i.e., equal phase, which is equivalent to a synchronization effect. This means two or more sound waves are triggered and arrive simultaneously. Theoretically, equal phase is a necessary condition for effective acoustic coupling. That is, only sound waves with the same phase characteristics can achieve effective coupling and superposition; otherwise, phase differences will cause local interference or cancellation.

[0019] Furthermore, the cross-section of the acoustic channel includes a cross-sectional line q near the center of the phase plug. i And the exponential cross-sectional curve y near the outer side of the phase plug i , i refers to the i-th acoustic channel from the center of the phase plug to the outside.

[0020] Furthermore, the exponential cross-sectional curve y i The function formula is y i =a x Where a is a constant greater than 1. Each acoustic channel must follow the same y=a x An exponential model is used to ensure consistent acoustic wave transmission characteristics in each channel. This effectively reduces coupling distortion at the exit points of each acoustic wave channel.

[0021] Furthermore, the simulated acoustic path d of the sound wave in the sound wave channel i =q i +c i The input end of the phase plug is a conical surface, and the cross-sectional curve of the conical surface in the acoustic channel is c, E. i For q i The intersection with c, c i For E i The path length between points E1 and E1 on the cross-sectional curve c is given here. The simulated sound path of the sound wave in each sound wave channel is given here. Since the speed of sound propagation is constant, the equal phase of the sound wave can be achieved by ensuring that the distance of the simulated sound path in each sound wave channel is equal. This section concretizes the abstract theory and provides a specific way to realize the equal phase of the sound wave.

[0022] Furthermore, E1 is the simulated sound source point of the diaphragm. The driver, as the sound source, has its theoretical sound source point located at the physical center of the voice coil. The input end of this phase plug has a conical surface that matches the driver diaphragm. Assuming the voice coil and its frame are rigid bodies, then E1 is the simulated sound source point of the diaphragm.

[0023] Furthermore, S i / s i =b,S i Let s be the output port area of ​​the i-th acoustic channel. i Let be the area of ​​the input port of the i-th sound wave channel, and b be a constant. If there are 3 sound wave channels, according to the principle of equal transmission ratio, the ratio of the area of ​​the input port to the area of ​​the output port of the three sound wave channels is the same, then the transmission ratio of the three channels is equal, and S1 / s1 = S2 / s2 = S3 / s3.

[0024] Furthermore, the phase plug includes a tapered input end and an implant located at the middle of the input end. The outer diameter of the implant matches the inner diameter of the intermediate frequency driver. The phase plug is implanted into the intermediate frequency driver through the implant, and the tapered surface matches the diaphragm of the intermediate frequency driver.

[0025] The implantable design has the following advantages: First, the high-frequency sound generation region of the cone-shaped diaphragm driver is concentrated in the central part. Through the implantable structure design, a wider high-frequency response can be obtained, effectively extending the upper frequency limit f. 上 This increases the effective working bandwidth of the horn. Secondly, it optimizes the piston vibration compliance of the diaphragm, avoiding the nonlinear distortion caused by the air cushion effect within the convex cap in externally pressurized systems. Thirdly, the implanted design allows the voice coil to communicate with the outside environment through a ring-shaped channel formed with the implanted part. During operation, convection cooling is achieved through piston vibration, effectively reducing heat loss and overheating damage caused by temperature rise, thus improving system efficiency and reliability.

[0026] A method for designing and manufacturing a phase plug for loudspeakers, using computer-aided design (CAD) software, ensures that each annular acoustic wave channel on the phase plug simultaneously meets the following conditions:

[0027] (1) Same exponential model: The cross section of the acoustic channel is an exponential cross section and the constant a of the exponential function of each acoustic channel is equal;

[0028] (2) Equal phase: The simulated sound paths of the sound waves in each sound wave channel are equal;

[0029] (3) Equal transmission ratio: The ratio of the area of ​​the input port to the area of ​​the output port of each acoustic channel is the same;

[0030] In specific applications in design and manufacturing, the following steps are included:

[0031] S1: Determine the relevant parameters based on the technical requirements and design objectives of the horn loudspeaker;

[0032] S1-1: Frequency response range of the reference driver, combined with the target operating bandwidth f of the horn loudspeaker. 下 ~f 上 Determine the range of the horn's length;

[0033] S1-2: The range of compression ratio can be calculated by referring to the sensitivity and power of the driver and combining it with the target maximum sound pressure level;

[0034] S1-3: The diameter of the phase plug outlet (i.e., the throat) can be calculated from the compression ratio = diaphragm area / throat area;

[0035] S2: Based on the equivalent sound path simulation algorithm, and with the help of computer CAD-aided drafting software, the structural model and related dimensions of the phase plug can be determined under the conditions of simultaneously satisfying the three requirements of equal simulated sound path, equal transmission ratio, and the same exponential model.

[0036] Furthermore, in addition to the steps described above, the following steps are also included:

[0037] S3: Using 3D printing technology, a phase plug model is created, matched with a driver, and a baffle test method is used. With the help of acoustic testing software, the phase response of each channel is measured. After repeatedly correcting the deviation values ​​of the relevant dimensions, the phase curves of each channel are finally made to coincide. The coincidence of the phase curves indicates that the phases are equal, and the precise size and structure of the phase plug can be determined.

[0038] S4: Assemble the appropriate horn, test and compare relevant parameters with design target parameters, and adjust the gap between the diaphragm and phase plug using annular shims to improve f. 上 Adjust the horn length to extend f 下 , make f 上 ~f 下 Achieve design goals;

[0039] S5: Use a CNC machining center to create separate molds for each component and produce finished products;

[0040] S6: Using a CNC machining center, an assembly template with the same curvature as the diaphragm is produced by contour machining.

[0041] S7: Assembly. Apply glue to each positioning platform, insert the positioning wing plate into the corresponding positioning slot, use the assembly template for positioning, apply pressure until the wing plate reaches the positioning platform, and remove the assembly template after the glue has cured.

[0042] In summary, the technical solution of this invention has the following advantages:

[0043] Implanted structures effectively reduce nonlinear distortion, improve heat dissipation efficiency, increase system reliability, and expand f... 上 .

[0044] The same exponential transmission structure—each subdivided acoustic channel adopts the same exponential model waveguide structure, so that the acoustic transmission characteristics are consistent and the distortion is minimized.

[0045] Equiphase transmission design – an innovative equivalent simulation algorithm is proposed, which greatly simplifies the calculation of acoustic paths and lays the foundation for achieving equiphase and coupled superposition of various acoustic wave channels.

[0046] Equal transmission ratio design – This innovative approach introduces the concept of equal transmission ratio, enabling equal-efficiency transmission across all acoustic channels. Attached Figure Description

[0047] Figure 1 This is the SPL-f curve.

[0048] Figure 2 This is a three-dimensional schematic diagram of a phase plug.

[0049] Figure 3 This is a schematic diagram of the assembly of the phase plug and the intermediate frequency driver.

[0050] Figure 4 This is a schematic diagram of the acoustic channel input port at the phase plug input end.

[0051] Figure 5 This is a schematic diagram of the acoustic channel output port at the output end of the phase plug.

[0052] Figure 6 This is a schematic diagram of a loudspeaker.

[0053] Figure 7 A schematic diagram of the phase plug manufacturing process.

[0054] Figure 8 for Figure 7 Top view.

[0055] Figure 9 A schematic diagram of installing a template during the phase plug manufacturing process.

[0056] Figure 10 For y=a x The coordinate model diagram of the exponential model.

[0057] Figure 11 This table shows the phase response curves for each acoustic channel.

[0058] Figure 12 This is a test table for the pointing of the phase plug.

[0059] Figure 13 This is a test table for the efficiency of the phase plug.

[0060] Figure 14 This is a distortion test table for this phase plug. Detailed Implementation

[0061] The present invention will now be described in conjunction with specific embodiments.

[0062] like Figure 2 , 3 As shown, a phase plug 1 for sound reinforcement includes two or more annular sound wave channels. Specifically, in this embodiment, the phase plug 1 is provided with three annular sound wave channels, namely sound wave channel K1, sound wave channel K2 and sound wave channel K3 from the center to the periphery.

[0063] In the three sound wave channels mentioned above, the cross-section of the sound wave channel is an exponential cross-section and the constant 'a' of the exponential function of each sound wave channel is equal (called the same exponential model). The ratio of the area of ​​the input port to the area of ​​the output port of each sound wave channel is the same (called equal transmission ratio). The simulated sound path of the sound wave in each sound wave channel is equal (called equal phase).

[0064] For the characteristics of the same exponential model, each acoustic channel adopts the following design:

[0065] like Figure 3 , 4 As shown in Figures 5 and 10, the cross-section of the acoustic channel includes the cross-sectional line q near the center of phase plug 1. i And the exponential cross-sectional curve y near the outer side of phase plug 1 i 'i' refers to the i-th acoustic wave channel extending from the center of phase plug 1 to its outer edge. The exponential cross-sectional curve y... i The function formula is y i =a x , where a is a constant greater than 1. Each acoustic channel consisting of l / L must follow the same y=a x The exponential model ensures that 'a' has the same value in sound wave channels K1, K2, and K3, guaranteeing consistent sound wave transmission characteristics for each channel. This effectively reduces coupling distortion at the exit points of each sound wave channel.

[0066] Considering the characteristics of equal phase (or equal acoustic path), each acoustic channel adopts the following design:

[0067] like Figure 3 As shown, the simulated acoustic path d of the acoustic wave channel i =q i +c i The input end of phase plug 1 is a conical surface, and the cross-sectional curve of the conical surface in the acoustic channel is c, E. i For q i The intersection with c, ci For E i The path length between points E1 and E2 on the cross-sectional curve c. Specifically, in the three acoustic channels of this embodiment, E1 is the simulated sound source point of the diaphragm 5, E0 is the theoretical sound source point of the diaphragm 5, the simulated sound path d1 is curve E1O1, the simulated sound path d2 is curve E1E2+E2O2, and the simulated sound path d3 is curve E1E3+E3O3. Therefore, d1 = d2 = d3, and E1O1 = E1E2+E2O2 = E1E3+E3O3.

[0068] This section presents the simulated sound path of the sound wave in each sound wave channel. Since the speed of sound propagation is constant, equal phase of the sound waves can be achieved simply by ensuring that the distance of the simulated sound path in each sound wave channel is equal. This section concretizes the abstract theory, providing a concrete way to achieve equal phase of sound waves. E1 is the simulated sound source point of diaphragm 5. The driver, as the sound source, has its theoretical sound source point located at the physical center of the voice coil. The input end of the phase plug 1 has a conical surface that matches the driver diaphragm 5. Assuming that the voice coil and its frame are rigid bodies, then E1 is the simulated sound source point of diaphragm 5.

[0069] To accommodate the equal transmission ratio, each acoustic channel is designed as follows:

[0070] like Figure 3-5 As shown, S i / s i =b,S i Let s be the output port area of ​​the i-th acoustic channel. i Let be the area of ​​the input port of the i-th sound wave channel, and b be a constant. If there are 3 sound wave channels, according to the principle of equal transmission ratio, the ratio of the area of ​​the input port to the area of ​​the output port of the three sound wave channels is the same, then the transmission ratio of the three channels is equal, and S1 / s1 = S2 / s2 = S3 / s3.

[0071] In addition, such as Figure 1 , 2 As shown, as a preferred embodiment, the phase plug 1 adopts an implantable structural design and is implanted into the intermediate frequency driver 2. Specifically, the phase plug 1 includes a tapered input end and an implant 3 located in the middle of the input end. The outer diameter of the implant 3 matches the inner diameter of the intermediate frequency driver 2. The phase plug 1 is implanted into the intermediate frequency driver 2 through the implant 3, and the tapered surface matches the diaphragm 5 of the intermediate frequency driver 2.

[0072] In addition, in order to manufacture a phase plug 1 that simultaneously satisfies the above-mentioned characteristics, the present invention provides a design and manufacturing method for amplification phase plug 1, as follows:

[0073] S1: Determine the relevant parameters based on the technical requirements and design objectives of the horn loudspeaker;

[0074] S1-1: Frequency response range of the reference driver, combined with the target operating bandwidth f of the horn loudspeaker. 下 ~f 上 Determine the range of the horn's length;

[0075] S1-2: The range of compression ratio can be calculated by referring to the sensitivity and power of the driver and combining it with the target maximum sound pressure level;

[0076] S1-3: The diameter of the phase plug 1 outlet (i.e., the throat) can be calculated from the compression ratio = diaphragm 5 area / throat area;

[0077] S2: Based on the equivalent sound path simulation algorithm, and with the aid of computer-aided CAD software, while simultaneously satisfying the following conditions: equal simulated sound path (E1O1= E1E2+E2O2= E1E3+E3O3), equal transmission ratio (S1 / s1= S2 / s2= S3 / s3), and the same exponential model (y i =a x Under the conditions of (same 'a' value), the structural model and related dimensions of phase plug 1 can be determined. Then, using acoustic testing software, the phase response curves of channels 1, 2, and 3 are tested to assist in fine-tuning and correcting the phase plug structure. Finally, the phase curves of the three channels are made to coincide. Coincidence of phase curves indicates equal phase, meaning the effective acoustic paths of the three channels are equal. At this point, at the outlet, the full coupling and superposition of the sound waves from each channel forms an equiphase wavefront with consistent characteristics. Theoretically, an equiphase wavefront will ensure uniform and consistent horn directivity control and minimize distortion caused by interference. Figure 11 The table shows the phase response curves for each acoustic channel. In the table, 1, 2, and 3 are the phase response curves when channels K1, K2, and K3 are individually active, while 1+2+3 are the phase response curves when channels K1, K2, and K3 are simultaneously active. As can be seen from the table, the four lines are basically overlapping, indicating that each channel is in phase.

[0078] S3: Using 3D printing technology, a model of phase plug 1 is made, matched with a driver, and the phase response of each channel is measured using the barrier test method and acoustic testing software. After repeatedly correcting the deviation values ​​of the relevant dimensions, the phase curves of each channel are finally made to coincide, and the precise size and structure of phase plug 1 can be determined.

[0079] S4: As Figure 6 As shown, assemble the corresponding horn, test and compare the relevant parameters with the design target parameters, and adjust the gap between the diaphragm 5 and the phase plug 1 with the annular shim 6 to improve f. 上 Adjust the horn length L h To extend f 下 , make f 上 ~f 下 Achieve design goals;

[0080] S5: Use a CNC machining center to create separate molds for each component and produce finished products;

[0081] S6: As Figure 7-9 As shown, a CNC machining center was used to fabricate an assembly template 9 with the same curvature as the diaphragm 5 using a contour machining method.

[0082] S7: Assembly. Apply glue to each positioning platform 4, insert the positioning wing plate 7 into the corresponding positioning groove 8, use the assembly template 9 for positioning, apply pressure until the wing plate reaches the positioning platform 4, and remove the assembly template 9 after the glue has cured.

[0083] Using the above technical solution, the three acoustic channels employ the same exponential model, resulting in the lowest transmission distortion compared to parallel tubes, linear tubes, and parabolic tubes. The 'a' value is identical in each exponential model, ensuring consistent acoustic transmission characteristics for each channel. This effectively reduces coupling distortion at the exit points of each acoustic channel.

[0084] The three acoustic channels have equal transmission ratios, which will ensure that after the acoustic waves pass through each acoustic channel of this phase plug 1, they form an equivalent wavefront with the same transmission efficiency at the exit.

[0085] The three sound wave channels are equal in phase (equal acoustic paths). Equal phase is equivalent to a synchronization effect, meaning that two or more sound waves are triggered and arrive simultaneously. Since the speed of sound is a constant, to achieve equal phase, the simulated acoustic paths must be equal, which in turn ensures equal sound wave transmission times. Theoretically, equal phase is a necessary condition for effective sound wave coupling. In other words, only sound waves with the same phase characteristics can achieve effective coupling and superposition; otherwise, local interference or cancellation will occur due to phase differences.

[0086] The implantable design has the following advantages: First, the high-frequency sound generation region of the cone-shaped diaphragm driver is concentrated in the central part. Through the implantable structure design, a wider high-frequency response can be obtained, effectively extending the upper frequency limit f. 上 This increases the effective working bandwidth of the horn. Secondly, it optimizes the piston vibration compliance of the diaphragm 5, avoiding the nonlinear distortion caused by the air cushion effect within the convex cap in externally pressurized systems. Thirdly, the implanted design allows the voice coil to communicate with the outside environment through a ring-shaped channel formed with the implanted part. During operation, convection cooling is achieved through piston vibration, effectively reducing heat loss and overheating damage caused by temperature rise, thus improving system efficiency and reliability.

[0087] In summary, by adopting the technical solution of the present invention, combined with the appendix... Figure 12-14 It can be seen that the present invention has the following advantages:

[0088] Implanted structures effectively reduce nonlinear distortion, improve heat dissipation efficiency, increase system reliability, and expand f... 上 .

[0089] The same exponential transmission structure—each subdivided acoustic channel adopts the same exponential model waveguide structure, so that the acoustic transmission characteristics are consistent and the distortion is minimized.

[0090] Equiphase transmission design – an innovative equivalent simulation algorithm is proposed, which greatly simplifies the calculation of acoustic paths and lays the foundation for achieving equiphase and coupled superposition of various acoustic wave channels.

[0091] Equal transmission ratio design – This innovative approach introduces the concept of equal transmission ratio, enabling equal-efficiency transmission across all acoustic channels.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications, combinations and variations. In particular, there are manufacturing errors. It is impossible for the transmission ratios of each acoustic channel of the phase plug to be completely equal and equal in phase (simulated acoustic paths are equal). There may also be errors in the 'a' in the exponential model of different acoustic channels. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for designing and manufacturing a phase plug for sound amplification, characterized in that, by means of computer CAD aided drawing software, each annular sound wave channel on the phase plug simultaneously satisfies the following conditions: (1) same exponential model: the cross section of the sound wave channel is an exponential section and the constant a of the exponential function of each sound wave channel is equal; (3) equal transmission ratio: the area ratio of the input port and the output port of each sound wave channel is the same; the method comprises the following steps: S1: determining the relevant parameters according to the technical requirements and design goals of the horn loudspeaker; S1-2: calculating the range of compression ratio by referring to the sensitivity and power of the driver and combining the target maximum sound pressure level; S1-3: calculating the diameter of the throat by compression ratio = diaphragm area / throat area; S2: determining the structure model and related dimensions of the phase plug by means of computer CAD aided drawing software under the conditions of equal simulation sound path, equal transmission ratio and same exponential model; the method further comprises the following steps: S3: using 3D printing technology to produce a phase plug model, matching the driver, and using the obstacle plate test method to measure the phase response of each channel by means of acoustic test software, and repeatedly correcting the deviation value of the related dimensions to finally make the phase curves of each channel tend to coincide to determine the accurate size and structure of the phase plug; S5: using a numerical control machining center to produce a split mold of each part and produce a finished product; S6: using a numerical control machining center to produce an assembly template with the same curvature as the diaphragm in a copying processing manner; S7: assembling, gluing each positioning platform, inserting the positioning wing plate into the corresponding positioning groove, positioning with the assembly template, and pressing until the wing plate reaches the positioning platform, then removing the assembly template after the glue is cured. The phase plug for sound amplification comprises two or more annular sound wave channels, the cross section of the sound wave channels is exponential, the area ratio of the input and output of each sound wave channel is the same, and the phase of the sound wave in each sound wave channel is equal; the cross section of the sound wave channel comprises a cross section line q i close to the center of the phase plug and an exponential cross section curve y i close to the outside of the phase plug, i represents the i-th sound wave channel from the center of the phase plug to the outside; the function formula of the exponential cross section curve y i is y i =a x , wherein a is a constant and greater than 1; Si / si=b, Si is the output port area of the i-th sound wave channel, si is the input port area of the i-th sound wave channel, and b is a constant. The phase plug comprises a conical curved input end and an implant body arranged at the middle position of the input end, the outer diameter of the implant body matches the inner diameter of the mid-frequency driver, the phase plug is implanted into the mid-frequency driver through the implant body, and the conical curved surface matches the diaphragm of the mid-frequency driver. (2) Equal phase: the analog sound paths of the sound waves in each sound wave channel are equal; the analog sound path d of the sound wave channel is i =q i +c i , wherein the input end of the phase plug is a conical curved surface, the cross-sectional curve of the conical curved surface in the sound wave channel is c, E i =q i is the intersection of q and c, c i =E i 1, and E1 is the path length of the two points E and E1 on the cross-sectional curve c; the phase plug is provided with three sound wave channels, which are sound wave channel K1, sound wave channel K2 and sound wave channel K3 from the center to the periphery; E1 is the analog sound source point of the diaphragm, E0 is the theoretical sound source point of the diaphragm, the analog sound path d1 is the curve E1O1, the analog sound path d2 is the curve E1E2+E2O2, and the analog sound path d3 is the curve E1E3+E3O3, therefore, d1= d2= d3, and E1O1= E1E2+E2O2= E1E3+E3O3; ​ ​ ​ S1-1: In combination with the target working bandwidth f of the horn loudspeaker, the length range of the horn is determined by referring to the frequency response range of the driver 下 ~f 上 , determine the length range of the horn; ​ ​ ​ ​ ​ S4: Assemble corresponding horn, test relevant parameters and compare with design target parameters, adjust the gap between the diaphragm and phase plug with ring gasket to improve f 上 , adjust the horn length to extend f 下 , make f 上 ~f 下 reach the design target; ​ ​ ​ 2. The method of claim 1, wherein the phase plug is designed and manufactured for sound amplification. ​ 3. The method of claim 1, wherein the phase plug is designed and manufactured for sound amplification. ​

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