Coaxial cylindrical wave horn

Abstract

The utility model provides a coaxial cylindrical wave horn which comprises an intermediate frequency driver, an intermediate frequency phase plug, an intermediate frequency cylindrical wave converter, a high frequency driver, a high frequency phase plug and a high frequency cylindrical wave converter which share the same axis, the intermediate frequency phase plug is embedded in the intermediate frequency driver, and the high frequency driver is embedded in the intermediate frequency phase plug. According to the utility model, the intermediate-frequency sound axis and the high-frequency sound axis of the horn coincide to form a coaxial structure, so that the coupling characteristics of the intermediate-frequency cylindrical wave converter and the high-frequency cylindrical wave converter are optimized, and coaxial coupling of double cylindrical waves is realized.

Description

Technical Field

[0001] The utility model relates to a sound amplification device, and more particularly to a coaxial cylindrical wave horn. The intermediate frequency and high frequency sound axes of the horn coincide to form a coaxial structure, so that the coupling characteristics of the intermediate frequency converter and the high frequency converter are optimized, and the coaxial coupling of double cylindrical waves is realized. In addition, the utility model also relates to a design method of a coaxial cylindrical wave horn. Background Art

[0002] Traditional sound reinforcement systems, such as the prior art, Chinese patent, ZL201921547041.7, discloses a coaxial speaker. In this patent, the bass voice coil is arranged in the basin frame, so that the bass voice coil and the basin frame are arranged coaxially, and the tweeter is arranged in the bass voice coil. This utility model patent technology enables the speaker to output the treble synchronously while outputting the bass, and the bass voice coil and the tweeter do not interfere with each other, thereby ensuring the sound quality of the speaker.

[0003] However, the above-mentioned prior art is only applicable to the application of spherical waves emitted by point sound sources. The coaxial horns of linear sound sources and cylindrical waves in modern sound reinforcement systems also need to be designed accordingly in combination with the characteristics of linear sound sources and cylindrical waves.

[0004] The main requirements of modern professional sound reinforcement systems are: 1. High sound pressure level, which needs to be achieved through coupling and superposition; 2. Low distortion, which needs to be achieved through optimized structural design; 3. Uniform coverage, which needs to be achieved through good directional control. To meet the above requirements, line sound sources and cylindrical waves have obvious advantages over traditional point sound sources and spherical waves.

[0005] Theoretically, a point sound source is a spherical wave, and a line sound source is a cylindrical wave, and their transmission characteristics are essentially different. Figure 1 As shown in the figure, the wavefront generated by the point sound source 2 is a concentric sphere, which is called a spherical wave. Imagine that there is a spherical sound source in an infinite uniform medium, whose surface expands and contracts rapidly, and each point on the surface vibrates with the same phase and amplitude. The wave radiated to the surrounding medium is a spherical wave. This sound wave is spherically symmetric, that is, the magnitude of the sound pressure is only related to the distance from the center of the sphere. A sound source of any shape, as long as its size is much smaller than the wavelength, can be regarded as a point sound source and radiates spherical waves. For spherical waves, the sound intensity at any distance from the sound source is inversely proportional to the square of the distance, the sound pressure is inversely proportional to the distance, and the phase difference between the sound pressure and the vibration velocity is inversely proportional to the ratio of the radius of the spherical wave to the wavelength.

[0006] like Figure 2As shown in the figure, the wavefront generated by the line sound source 4 is a coaxial cylindrical wave, which is called a cylindrical wave. A cylindrical wave is a wave whose wavefront is a coaxial cylindrical wave. Imagine that there is an infinitely long uniform line sound source in an infinitely uniform medium, and the wave it generates is an ideal cylindrical sound wave. In a cylindrical sound wave, the sound pressure amplitude is uniformly distributed along the axial direction, and is inversely proportional to the square root of the distance from the axis along the radial direction. Its radial sound intensity is inversely proportional to the first power of the distance from the axis.

[0007] From the above acoustic theory analysis, it can be seen that the acoustic characteristics of the line sound source composed of cylindrical waves are far superior to the point sound source composed of traditional point spherical waves. Specifically, they are as follows: 1. Transmission characteristics---the efficiency is twice as high. 2. Good coupling characteristics, low distortion caused by interference. 3. Better directivity control (strong directivity in the vertical direction). Therefore, how to convert spherical waves into cylindrical waves has become the main focus of researchers in this industry.

[0008] Prior art, Chinese patent, CN201320153532.X, discloses a phase plug-implanted tweeter horn for sound reinforcement. This technology creates a path compensation effect by implanting a shuttle-shaped phase plug, which changes the transmission characteristics of the sound wave, converting the spherical wave into a cylindrical wave.

[0009] Modern acoustic theory believes that the theoretical conditions for the conversion of spherical waves to cylindrical waves are as follows: 1. The center distance between closely arranged independent sound sources is less than half of the wavelength of the upper frequency limit corresponding to the working bandwidth range. 2. Multiple independent sound sources are in-phase wavefronts, and the effective radiation area accounts for more than 80% of the total area. In theory, if any of the above two conditions is met, the conversion from spherical waves to cylindrical waves can be achieved.

[0010] Regarding the first condition, there are various structures of waveform converters in existing industry products. The basic principle is to make the sound paths of each channel the same by adjusting the bending of the waveguide (sound channel), that is, to achieve equal phase characteristics. The existing technology, Chinese patent, ZL200820207136.X, discloses a high-frequency directivity control converter for sound reinforcement. By setting up several transmission channels with equal acoustic paths, the conversion of spherical waves to cylindrical waves is achieved, and the directivity control of cylindrical waves is achieved. Utility Model Content

[0011] The technical problem to be solved by the utility model is to provide a coaxial cylindrical wave horn. The intermediate frequency and high frequency sound axes of the horn coincide to form a coaxial structure, so that the coupling characteristics of the intermediate frequency converter and the high frequency converter are optimized, and the coaxial coupling of double cylindrical waves is realized.

[0012] The utility model provides a coaxial cylindrical wave horn, comprising an intermediate frequency driver, an intermediate frequency phase plug, an intermediate frequency cylindrical wave converter, a high frequency driver, a high frequency phase plug, and a high frequency cylindrical wave converter which share the same axis, wherein the intermediate frequency phase plug is embedded in the intermediate frequency driver, and the high frequency driver is embedded in the intermediate frequency phase plug.

[0013] As an improvement, the intermediate frequency phase plug includes three parts with the same axis. The first part is a cylinder, which slides with the center hole of the intermediate frequency driver for positioning. The second part is a cylinder, and the third part is a frustum. The second and third parts match the diaphragm of the intermediate frequency driver and maintain a gap of 0.5-1 mm between the diaphragm.

[0014] As an improvement, the cone of the third part of the intermediate frequency phase plug is in the form of a shell, inside which there is a support structure for positioning the high frequency driver, the support structure is in the shape of a cylinder and has the same axis as the cone of the third part of the intermediate frequency phase plug.

[0015] As an improvement, the high-frequency phase plug is in the shape of a modified cone, and the end of the high-frequency phase plug pointing to the high-frequency driver is in the shape of a cone, and the end of the high-frequency phase plug pointing to the horn opening is a diameter line segment on the bottom circle of the cone and passing through the center of the bottom circle of the cone. Two planes pass through the diameter line segment, with the plane determined by the axis of the cone and the diameter line segment as the reference plane, are symmetrical to each other, and intersect with the cone.

[0016] As an improvement, the included angle between the two planes is equal to the apex angle of the cone, and the modified cone is formed by the cone and the two planes.

[0017] As an improvement, the intermediate frequency cylindrical wave converter is composed of an intermediate frequency cylindrical wave converter inner shell and an intermediate frequency cylindrical wave converter outer shell. The intermediate frequency cylindrical wave converter inner shell is a modified frustum, and the top circular end of the frustum is connected to the intermediate frequency phase plug. The frustum is modified in that the frustum surface and the bottom circular part are connected to two planes. The two planes respectively pass through a line segment parallel to the bottom circle diameter. The distance between the line segment and the bottom circle diameter is the sum of the width of the high-frequency cylindrical wave converter opening and the thickness of the intermediate frequency cylindrical wave converter inner shell. The two planes are symmetrical to each other with the plane determined by the axis of the frustum and the bottom circle diameter as the reference plane. The modified frustum is surrounded by the frustum and the two planes. The difference in the sound wave propagation path on the surface of the modified frustum is less than one-fourth of the wavelength corresponding to the upper frequency limit adapted by the intermediate frequency driver.

[0018] The utility model also provides a design method for a coaxial cylindrical wave horn, and the design method comprises the following steps: step 1: selecting an intermediate frequency driver and a high frequency driver, so that the specification of the intermediate frequency driver is greater than or equal to 2-4 times the specification of the high frequency driver; step 2: according to the same compression ratio principle, calculating the diameter of the intermediate frequency phase plug and designing the intermediate frequency phase plug; step 3: according to the size of the intermediate frequency driver basin frame, calculating the height of the inner shell of the intermediate frequency cylindrical wave converter at the opening; step 4: according to the height of the inner shell of the intermediate frequency cylindrical wave converter at the opening, calculating the height of the high frequency phase plug; step 5: according to the height of the high frequency phase plug, selecting the length of the high frequency phase plug as the length of the high frequency phase plug 0.8 to 1.2 of the height; Step 6: Select the length of the inner shell of the intermediate frequency cylindrical wave converter according to the inclusive relationship between the inner shell of the intermediate frequency cylindrical wave converter and the high-frequency phase plug; Step 7: Design the high-frequency phase plug according to the length and height of the high-frequency phase plug; Step 8: Design the inner shell of the intermediate frequency cylindrical wave converter according to the diameter of the intermediate frequency phase plug, the height of the inner shell of the intermediate frequency cylindrical wave converter at the opening, and the length of the intermediate frequency cylindrical wave converter; Step 9: Design the high-frequency cylindrical wave converter according to the high-frequency phase plug and the inner shell of the intermediate frequency cylindrical wave converter; Step 10: Design the outer shell of the intermediate frequency cylindrical wave converter according to the dimensions of the inner shell of the intermediate frequency cylindrical wave converter and the intermediate frequency driver basin.

[0019] As an improvement, step 2 is specifically as follows: Step 2.1: calculate the compression ratio of the high-frequency driver; Step 2.2: calculate the intermediate frequency phase plug diameter based on the same compression ratio principle; Step 2.3: design the intermediate frequency phase plug based on the selected intermediate frequency driver, high-frequency driver specifications, and intermediate frequency phase plug diameter.

[0020] As an improvement, step 7 is specifically as follows: Step 7.1: Design a cone with the height of the high-frequency phase plug as the base circle diameter and the length of the high-frequency phase plug as the height; Step 7.2: Take a semicircle on the base circle of the cone and make a series of inscribed circles tangent to the base circle diameter and the base circle; Step 7.3: From the center of each inscribed circle, parallel to the center line of the cone, make the axis of the inscribed circle toward the vertex of the cone; Step 7.4: Each inscribed circle axis intersects with the surface of the cone, and each intersection constitutes an intersection line connecting the plane passing through the base circle diameter and the surface of the cone, and the intersection line and the diameter determine the first plane intersecting with the cone; Step 7.5: Take the plane determined by the axis of the cone and the base circle diameter line segment as the reference plane, pass through the base circle diameter line segment, be symmetrical to the first plane, make a second plane that intersects with the surface of the cone.

[0021] As an improvement, step 8 is specifically as follows: step 8.1: design a truncated cone with the diameter of the intermediate frequency phase plug as the top circle diameter and the height of the inner shell of the intermediate frequency cylindrical wave converter at the opening as the bottom circle diameter; step 8.2: take a semicircle on the bottom circle of the truncated cone, and make a third parallel line parallel to the bottom circle diameter and at a certain distance from the bottom circle diameter. The distance is the sum of the width of the high-frequency cylindrical wave converter opening and the thickness of the inner shell of the intermediate frequency cylindrical wave converter; step 8.3: make a third plane through the third parallel line and intersect with the surface of the truncated cone; step 8.4: check and calculate the acoustic wave transmission of the truncated cone surface. Step 8.5: On the bottom circle of the truncated cone, take another semicircle, and make a fourth parallel line parallel to the bottom circle diameter and at a certain distance from the bottom circle diameter. The distance is the sum of the width of the high-frequency cylindrical wave converter opening and the thickness of the inner shell of the intermediate-frequency cylindrical wave converter. Step 8.6: Take the plane determined by the axis of the truncated cone and the bottom circle diameter line segment as the reference plane, pass through the fourth parallel line, and be symmetrical with the third plane to make a fourth plane that intersects with the surface of the truncated cone.

[0022] Compared with the prior art, the beneficial effects brought about by the present invention are as follows: (1) The intermediate frequency cylindrical wave converter and the high frequency cylindrical wave converter adopt the same structural design principle, so that the intermediate frequency and high frequency sound waves pass through their own independent equal-path waveguides and achieve equal-phase coupling at the exit, thereby completing the conversion of the wave type from spherical wave to cylindrical wave. (2) The embedded coaxial structural design is adopted to achieve the synchronous diffusion of high frequency and intermediate frequency, making their directivity more uniform. (3) The structural design of compressing the intermediate frequency and high frequency in the same proportion is adopted to achieve the equivalent transmission of the two. The intermediate frequency and high frequency sound waves can both achieve the same propagation characteristics within the effective transmission range. (4) The same-waveform propagation of high frequency and intermediate frequency effectively improves the transmission efficiency of the two, making the sound field they cover and the acoustic characteristics consistent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of a point sound source and a spherical wave.

[0024] Figure 2 Schematic diagram of line sound source and cylindrical wave.

[0025] Figure 3A and Figure 3B It is a structural schematic diagram of an embodiment of the utility model.

[0026] Figure 4 It is a schematic structural diagram of a high frequency driver in one embodiment of the utility model.

[0027] Figure 5A It is a structural schematic diagram of a medium frequency driver in one embodiment of the utility model.

[0028] Figure 5B The figure is a schematic diagram of the diaphragm area of ​​a medium frequency driver in one embodiment of the utility model.

[0029] Figure 5C This is a schematic diagram of the structure of an intermediate frequency driver and an intermediate frequency phase plug in one embodiment of the utility model.

[0030] Figure 5D This is a schematic diagram of the area of ​​the intermediate frequency driver after being compressed by the intermediate frequency phase plug in one embodiment of the utility model.

[0031] Figure 6 It is a schematic diagram of two adjacent coaxial cylindrical wave horns vertically superimposed and coupled to form a linear sound source in one embodiment of the utility model.

[0032] Fig. 7A and Figure 7B It is a schematic diagram of modifying a cone constituting a high-frequency phase plug in one embodiment of the utility model.

[0033] Figure 8 It is a schematic diagram of modifying the truncated cone constituting the inner shell of the intermediate frequency waveform converter in one embodiment of the utility model. DETAILED DESCRIPTION

[0034] The utility model will be further described below in conjunction with the accompanying drawings.

[0035] like Figure 1 , schematic diagram of a point sound source and a spherical wave, as shown, the wavefront generated by the point sound source 2 is a concentric sphere, which is called a spherical wave. Imagine that there is a spherical sound source in an infinite uniform medium, whose surface expands and contracts rapidly, and each point on the surface vibrates with the same phase and amplitude, and the wave radiated to the surrounding medium is a spherical wave. This sound wave is spherically symmetric, that is, the magnitude of the sound pressure is only related to the distance from the center of the sphere. A sound source of any shape, as long as its size is much smaller than the wavelength, can be regarded as a point sound source, radiating spherical waves. For spherical waves, the sound intensity at any distance from the sound source is inversely proportional to the square of the distance. As shown in the figure, when the distance from the sound source increases from R to R2, which is twice R, the area of ​​the wavefront increases from A to 4A, and the sound intensity drops to 1 / 4.

[0036] like Figure 2 , schematic diagram of a line sound source and a cylindrical wave, as shown, the wavefront generated by the line sound source 4 is a coaxial cylindrical wave, which is called a cylindrical wave. A cylindrical wave is a wave whose wavefront is a coaxial cylindrical wave. Imagine that there is an infinitely long uniform line sound source in an infinitely uniform medium, and the wave it generates is an ideal cylindrical sound wave. In a cylindrical sound wave, the sound pressure amplitude is uniformly distributed along the axial direction, and is inversely proportional to the square root of the distance from the axis along the radial direction. Its radial sound intensity is inversely proportional to the first power of the distance from the axis. As shown in the figure, when the sound source distance increases from R to R2, which is twice R, the area of ​​the wavefront increases from A to 2A, and the sound intensity drops to 1 / 2.

[0037] Figure 3A , Figure 3B This is a schematic diagram of the structure of an embodiment of the utility model. Figure 3A is a vertical plane section view, Figure 3B is a cross-sectional view of a horizontal plane. Figure 3A , Figure 3B As shown, in one embodiment of the utility model, a coaxial cylindrical wave horn 2 includes an intermediate frequency driver 4, an intermediate frequency phase plug 6, an intermediate frequency cylindrical wave converter 8, a high frequency driver 10, a high frequency phase plug 12, and a high frequency cylindrical wave converter 14, which share the same axis OO. The intermediate frequency phase plug 6 is embedded in the intermediate frequency driver 4, and the high frequency driver 10 is embedded in the intermediate frequency phase plug 6. In order not to interfere with the illustration of other components, the intermediate frequency driver 4 is illustrated by a dotted line. The outer surface of the high frequency phase plug 12 forms a waveguide channel for high frequency sound waves with the shell that maintains a certain distance therefrom, forming a high frequency cylindrical wave converter 14.

[0038] like Figure 3A , Figure 3B As shown, the intermediate frequency phase plug 6 includes three parts having the same axis OO, the first part 16 is a cylinder, which is slidably matched with the center hole 18 of the intermediate frequency driver for positioning, the second part 20 is a cylinder, and the third part 24 is a frustum, the second part 20 and the third part 24 match the diaphragm 26 of the intermediate frequency driver 4, and maintain a gap of 0.5-1 mm between the diaphragm 26.

[0039] like Figure 3A , Figure 3B As shown, the frustum of the third part 24 of the intermediate frequency phase plug 6 is in the form of a shell, inside which there is a support structure 28 for positioning the high frequency driver 10 . The support structure 28 is in the shape of a cylinder and has the same axis OO as the frustum of the third part 24 of the intermediate frequency phase plug 6 .

[0040] like Figure 3A , Figure 3B As shown, the high-frequency phase plug 12 is in the shape of a modified cone, and the end of the high-frequency phase plug 12 pointing to the high-frequency driver 10 is in the shape of a cone, and the end of the high-frequency phase plug 12 pointing to the horn opening 30 is a diameter line segment AB on the bottom circle of the cone and passing through the center of the bottom circle of the cone, and two planes 32 and 34 pass through the diameter line segment AB, with the plane determined by the axis OO of the cone and the diameter line segment AB as the reference plane, are symmetrical to each other, and intersect the cone.

[0041] like Figure 3A , Figure 3B As shown, the included angle α between the two planes 32 and 34 is equal to the apex angle β of the cone, and the modified cone is formed by the cone and the two planes 32 and 34 .

[0042] like Figure 3A , Figure 3B As shown, the intermediate frequency cylindrical wave converter 8 is composed of an intermediate frequency cylindrical wave converter inner shell 36 and an intermediate frequency cylindrical wave converter outer shell 38. The intermediate frequency cylindrical wave converter inner shell 36 is a modified frustum, and the top circular end of the frustum is connected to the intermediate frequency phase plug 6. The frustum is modified in that the frustum surface and the bottom circular part are connected to two planes 40 and 42. The two planes 40 and 42 respectively pass through a line segment parallel to the bottom circle diameter CD. The distance between the line segment and the bottom circle diameter CD is the sum of the width of the high frequency cylindrical wave converter opening and the thickness of the intermediate frequency cylindrical wave converter inner shell. The two planes 40 and 42 are symmetrical to each other with the plane determined by the axis OO of the frustum and the bottom circle diameter CD as the reference plane. The modified frustum is surrounded by the frustum and the two planes 40 and 42. The difference in the sound wave propagation path on the surface of the modified frustum is less than one-fourth of the wavelength corresponding to the upper frequency limit adapted by the intermediate frequency driver.

[0043] The utility model also provides a design method for a coaxial cylindrical wave horn, which comprises the following steps:

[0044] Step 1: Select the mid-frequency driver and high-frequency driver so that the specifications of the mid-frequency driver are greater than or equal to 2-4 times the specifications of the high-frequency driver. In the industrial standard of modern sound reinforcement, the specifications of the driver are usually nominally based on the diaphragm diameter in inches. Common high-frequency driver specifications are as follows: High-frequency driver: 1", 2", 3", 4", such as Figure 4 As shown, the high-frequency driver 10 includes a diaphragm 44, with the diameter DH1 of the diaphragm 44 being the reference nominal size of the high-frequency driver, and the throat diameter being DH0.

[0045] Commonly used high-frequency driver specifications are shown in the following table:

[0046]

[0047] Commonly used medium frequency drivers: 4", 6", 8", 10", such as Figure 5A As shown, the intermediate frequency driver 4 includes a diaphragm 26, and the diameter DM0 of the diaphragm 26 is used as the reference nominal size.

[0048] Step 2: According to the principle of the same compression ratio, calculate the diameter of the intermediate frequency phase plug and design the intermediate frequency phase plug. In order to meet the application requirements of modern sound reinforcement "high sound pressure, long-range coverage", the design of the driver of professional sound reinforcement needs to have high sensitivity and withstand power. According to the sound pressure level calculation formula: Among them, P is the sound pressure level at power W, P0 is the sensitivity, and W0 is its corresponding power. It can be seen from the formula that P is positively correlated with P0 and W. Therefore, in order to obtain a higher sound pressure level, the most effective way is to increase the sensitivity of the speaker, and in order to increase the sensitivity, the effective structural design is to adopt a compression drive mode. In the field of sound reinforcement, the concept of compression ratio is similar to the concept of acceleration in physics, and is positively correlated with transmission efficiency. That is: the higher the compression ratio, the higher the efficiency of the sound reinforcement horn and the longer the transmission distance.

[0049] Step 2 is specifically as follows: Step 2.1: Calculate the compression ratio of the high frequency driver; Step 2.2: Calculate the diameter of the intermediate frequency phase plug according to the same compression ratio principle; Step 2.3: Design the intermediate frequency phase plug according to the selected specifications of the intermediate frequency driver, high frequency driver, and the diameter of the intermediate frequency phase plug.

[0050] In step 2.1, the common structure of high-frequency drivers is as follows Figure 4 As shown, DH1 is the diaphragm diameter and DH0 is the outlet (throat) diameter. In the existing industry standards, the simplified compression ratio algorithm is the ratio of the diaphragm to the throat area. At the same time, assuming that the diaphragm structure is a rigid body, its projection plane is usually used as the diaphragm area reference plane. Therefore, the compression ratio δH algorithm of the high-frequency driver is: and

[0051] Right now but Among them, SH1 is the area of ​​the diaphragm projection plane, and SH0 is the area of ​​the throat plane.

[0052] In step 2.2, in order to make the high / mid-frequency horns of the patent structure have the same efficiency, this patent introduces the concept of "compression ratio" in the design of the mid-frequency driver compression structure, that is: according to the compression ratio of the selected high-frequency compression driver, the matching mid-frequency phase plug is designed to make its compression ratio consistent with that of the high-frequency driver. Figure 5A As shown in the figure, the nominal diameter of the diaphragm of the mid-frequency driver is DM0. Correspondingly, assuming that the diaphragm structure is a rigid body, its projection plane is usually used as the reference plane of the diaphragm area. Figure 5B As shown in the figure, the diaphragm area of ​​the intermediate frequency driver is equal to the circular area SM1 of the diaphragm diameter DM0. Figure 5C As shown, the intermediate frequency driver 4 is embedded with an intermediate frequency phase plug 6, whose diameter is d. Correspondingly, as Figure 5D As shown in the figure, after the intermediate frequency driver is compressed by the intermediate frequency phase plug, the area of ​​the ring is SM1. Therefore, the compression ratio of the intermediate frequency driver can be calculated: 中其 Depend on Figures 5A to 5D It can be seen that by adjusting the phase plug diameter d matched to the midrange speaker, SM1 can be adjusted. When δH≈δM, year-on-year compression can be achieved.

[0053] In step 2.3, if Figure 3A , Figure 3B As shown, the size of each part of the intermediate frequency phase plug 6 can be determined according to the selection of the intermediate frequency driver and the diameter of the intermediate frequency phase plug. The first part 16 is a cylinder, which is slidably matched with the center hole 18 of the intermediate frequency driver for positioning. The second part 20 is a cylinder, and the third part 24 is a frustum. The second part 20 and the third part 24 match the diaphragm 26 of the intermediate frequency driver 4, and maintain a gap of 0.5-1 mm with the diaphragm 26.

[0054] In step 2.3, if Figure 3A , Figure 3B As shown, according to the selection of the high-frequency driver and the diameter of the intermediate frequency phase plug, the shell of the cone of the third part 24 of the intermediate frequency phase plug 6 can be determined, and inside the shell there is a support structure 28 for positioning the high-frequency driver 10. The support structure 28 is barrel-shaped and has the same axis OO as the cone of the third part 24 of the intermediate frequency phase plug 6.

[0055] Step 3: Calculate the height of the inner shell of the intermediate frequency cylindrical wave converter at the opening according to the size of the intermediate frequency driver basin frame. Figure 6 As shown, in order to support and fix the intermediate frequency driver 4 and its diaphragm, the intermediate frequency driver includes a basin frame 46. Considering that the coaxial cylindrical wave horn will use a plurality of vertically superimposed coupling methods in the application to form a linear sound source. Therefore, the size of the intermediate frequency driver basin frame should be less than or equal to the height of the intermediate frequency cylindrical wave converter housing at the opening. Figure 3A As shown, the height CD of the inner shell of the intermediate frequency cylindrical wave converter at the opening can be calculated by deducting twice the wall thickness of the intermediate frequency cylindrical wave converter at the opening (generally 5 mm) and twice the width of the intermediate frequency cylindrical wave converter at the opening (i.e. the width of the intermediate frequency cylindrical wave waveguide channel at the opening).

[0056] Step 4: Calculate the height of the high-frequency phase plug based on the height of the inner shell of the intermediate frequency cylindrical wave converter at the opening. Figure 3A As shown, the height CD of the inner shell of the medium frequency cylindrical wave converter at the opening is subtracted by twice the wall thickness of the inner shell of the medium frequency cylindrical wave converter at the opening (generally 5 mm), and then subtracted by twice the gap of the high frequency cylindrical wave converter at the opening (generally 5 mm), and the height AB of the high frequency phase plug can be calculated.

[0057] Step 5: According to the height of the high-frequency phase plug, the length of the high-frequency phase plug is selected to be 0.8 to 1.2 of the height of the high-frequency phase plug. Figure 3AAs shown, in order to reduce the attenuation of the energy of the sound wave in the high-frequency cylindrical wave converter channel, the length LH of the high-frequency phase plug should be selected to be a smaller value. In addition, considering that the high-frequency phase plug needs to be corrected on the cone later, and it is also necessary to meet the containment relationship of the inner shell of the intermediate frequency cylindrical wave converter to the high-frequency phase plug, the length of the high-frequency phase plug is preferably 0.8 to 1.2 of the height of the high-frequency phase plug.

[0058] Step 6: According to the containment relationship between the inner shell of the intermediate frequency cylindrical wave converter and the high frequency phase plug, select the inner shell length of the intermediate frequency cylindrical wave converter. Figure 3A As shown, the inner shell of the intermediate frequency cylindrical wave converter includes the high frequency phase plug. Therefore, the inner shell length LM of the intermediate frequency cylindrical wave converter can be calculated according to the length LH of the high frequency phase plug, the thickness of the high frequency driver, and the degree of inclusion of the intermediate frequency phase plug to the high frequency driver.

[0059] Step 7: Design the high-frequency phase plug according to the length and height of the high-frequency phase plug. Step 7 specifically includes the following steps.

[0060] Step 7.1: Design a cone with the high-frequency phase plug height AB as the base circle diameter and the high-frequency phase plug length LH as the height.

[0061] Step 7.2: Take a semicircle on the base of the cone and make a series of inscribed circles that are tangent to the base diameter and the base. Fig. 7A As shown, on the base circle of the cone, the center O forms a semicircle with the diameter aa of the circle O and the upper semicircle arc. A series of inscribed circles with B, C, and D as the center are tangent to the diameter aa and the semicircle arc at points b, c, and d respectively.

[0062] Step 7.3: Draw the axis of each inscribed circle from the center of each inscribed circle parallel to the centerline of the cone toward the apex of the cone. Figure 7B As shown, the centers of the inscribed circles B, C, D are parallel to the center line of the cone, and the axes are directed toward the apex of the cone, intersecting the cone at points B', C', D'.

[0063] Step 7.4: Each inscribed circle axis intersects with the surface of the cone, and each intersection point forms an intersection line where a plane passing through the base circle diameter meets the surface of the cone. The intersection line and the diameter determine the first plane that intersects with the cone. Figure 7B As shown, each inscribed circle axis intersects the conical surface at B', C', D', and the arc aB'C'D'a forms an intersection line where the plane aB'C'D'a passing through the base circle diameter aa connects with the conical surface. The intersection line aB'C'D'a and the diameter aa determine the first plane aB'C'D'a intersecting the cone.

[0064] Step 7.5: Take the plane determined by the axis of the cone and the bottom circle diameter line segment as the reference plane, pass through the bottom circle diameter line segment, and make a second plane symmetrical to the first plane and intersect with the cone surface. Figure 3A and Figure 3B As shown, the plane determined by the axis OO of the cone and the bottom circle diameter line segment aa is used as the reference plane. A second plane 34 is made symmetrically with the first plane 32 through the bottom circle diameter line segment aa and intersects with the surface of the cone.

[0065] At this time, the cone is modified by the first plane 32 and the second plane 34 to form a high-frequency phase plug of the utility model, which has the advantage that the sound wave propagation path from the cone vertex through the cone surface and the plane to the horn opening 30 is of equal length. Fig. 7A and Figure 7B As shown, taking the inscribed circle with the center C as an example, the inscribed circle is tangent to the arc of the base circle at point c, and is tangent to the diameter aa at point C1. From the center C, parallel to the center line OO of the cone, the axis of the inscribed circle is drawn in the direction of the cone vertex O, and intersects with the cone surface at point C'. With CC' as the axis and the inscribed circle with the center C as the base circle, a small cone can be generated. Because on the cone surface, the line segments from the cone vertex C' to any point on the base circle are of equal length, so on the surface of the small cone, the line segment C'c is of equal length to the line segment C'C1. Correspondingly, on the surface of the high-frequency phase plug, the line segment OC'c is of equal length to the line segment OC'C1. Moreover, the sound wave propagation path always propagates along the shortest path from the high sound pressure area to the low sound pressure area. On the first plane, the sound wave propagation path is propagated along the route C'C1 perpendicular to the diameter aa. Based on the same principle, on the surface of the high-frequency phase plug, the acoustic wave propagation path Oa is equal in length to the path 0B'B1, the path OC'C1, and the path OD'D1.

[0066] Furthermore, according to geometric principles, the angle α between the two planes 32 and 34 is equal to the apex angle β of the cone.

[0067] Step 8: Design the inner shell of the intermediate frequency cylindrical wave converter according to the diameter of the intermediate frequency phase plug, the height of the inner shell opening of the intermediate frequency cylindrical wave converter, and the length of the intermediate frequency cylindrical wave converter. Step 8 specifically includes the following steps.

[0068] Step 8.1: Design a truncated cone with the diameter d of the intermediate frequency phase plug as the top circle diameter and the height CD of the inner shell of the intermediate frequency cylindrical wave converter at the opening as the bottom circle diameter.

[0069] Step 8.2: Take a semicircle on the bottom circle of the truncated cone, and make a third parallel line parallel to the bottom circle diameter and at a certain distance from the bottom circle diameter. The distance is the sum of the width of the high-frequency cylindrical wave converter opening and the thickness of the inner shell of the medium-frequency cylindrical wave converter. Figure 8As shown, on the bottom circle of the truncated cone, take a semicircle, and make a third parallel line L3 parallel to the bottom circle diameter CD and at a certain distance from the bottom circle diameter. The distance is the sum of the width of the high-frequency cylindrical wave converter opening and the thickness of the inner shell of the medium-frequency cylindrical wave converter.

[0070] Step 8.3: Make a third plane through the third parallel line and intersect with the frustum surface. Figure 3B As shown, a third plane 40 is made through the third parallel line L3 and intersects with the frustum surface.

[0071] Step 8.4: Check and calculate the sound wave propagation path on the surface of the truncated cone, so that the difference of the sound wave propagation path on the surface of the truncated cone is less than one-fourth of the wavelength corresponding to the upper frequency limit of the intermediate frequency driver adaptation. Each sound wave propagation path starts from the top circle edge of the truncated cone, and extends toward the bottom circle of the truncated cone on the surface of the truncated cone along the intersection line between the plane passing through the axis of the truncated cone and the surface of the truncated cone. However, when reaching the intersection line where the third plane 40 intersects with the surface of the truncated cone, because the sound wave propagation path is propagated from the high sound pressure area to the low sound pressure area along the shortest path, after the self-intersection line, the sound wave propagation path propagates along the corresponding points on the self-intersection line in a straight line perpendicular to the third parallel line L3. Because the third plane 40 and the surface of the truncated cone can intersect at different positions, the difference of the sound wave propagation path on the surface of the truncated cone changes. Therefore, in order to meet the requirements of the intermediate frequency sound wave coupling, the difference of the sound wave propagation path on the surface of the truncated cone should be less than one-fourth of the wavelength corresponding to the upper frequency limit of the intermediate frequency driver adaptation.

[0072] Step 8.5: On the bottom circle of the truncated cone, take another semicircle and make a fourth parallel line parallel to the bottom circle diameter and at a certain distance from the bottom circle diameter. The distance is the sum of the width of the high-frequency cylindrical wave converter opening and the thickness of the inner shell of the medium-frequency cylindrical wave converter. Figure 8 As shown, on the bottom circle of the truncated cone, take a semicircle, and make a fourth parallel line L4 parallel to the bottom circle diameter CD and at a certain distance from the bottom circle diameter. The distance is the sum of the width of the high-frequency cylindrical wave converter opening and the thickness of the inner shell of the medium-frequency cylindrical wave converter.

[0073] Step 8.6: Take the plane determined by the axis of the cone and the diameter of the bottom circle as the reference plane, pass through the fourth parallel line, and make a fourth plane symmetrical to the third plane and intersect with the cone surface. Figure 3B As shown, the plane defined by the axis OO of the truncated cone and the line segment of the bottom circle diameter is used as the reference plane, passes through the fourth parallel line L4, is symmetrical with the third plane 40, and a fourth plane 42 is made and intersects with the surface of the truncated cone. Because the fourth plane 42 is symmetrical with the third plane 40, accordingly, the difference in the sound wave propagation path on the surface of the truncated cone should also be less than one-fourth of the wavelength corresponding to the upper frequency limit adapted by the intermediate frequency driver.

[0074] As an optimization design, referring to the correction scheme of the high-frequency phase plug in step 7 by the first plane 32 and the second plane 34, when the angle between the third plane 40 and the fourth plane 42 is equal to the apex angle of the cone, the difference in the sound wave propagation path on the surface of the cone is zero, that is, the sound wave propagation paths are of equal length. At this time, the medium-frequency sound wave coupling effect is best.

[0075] On the other hand, because the design of the inner shell of the intermediate frequency cylindrical wave converter involves the selection of the intermediate frequency driver and the high frequency driver, as well as the requirements of the inner shell of the intermediate frequency cylindrical wave converter for the inclusion of the high frequency phase plug, the selection of the opening height CD and length LM of the inner shell of the intermediate frequency cylindrical wave converter, and the height AB and length LH of the high frequency phase plug need to be corrected through continuous design verification.

[0076] Step 9: Design the high-frequency cylindrical wave converter based on the high-frequency phase plug and the inner shell of the intermediate-frequency cylindrical wave converter. Figure 3A and Figure 3B As shown, the high-frequency phase plug 12 is contained by the inner shell 36 of the intermediate frequency cylindrical wave converter, and a waveguide channel for high-frequency sound waves is formed between the outer surface of the high-frequency phase plug 12 and the shell that is kept at a certain distance from it, thereby forming a high-frequency cylindrical wave converter 14. In order to reduce the number of parts, the inner surface of the inner shell 36 of the intermediate frequency cylindrical wave converter is formed to correspond to the outer surface of the high-frequency phase plug 12, that is, a waveguide channel for high-frequency sound waves is formed between the outer surface of the high-frequency phase plug 12 and the inner surface of the inner shell 36 of the intermediate frequency cylindrical wave converter that is kept at a certain distance from it, thereby forming a high-frequency cylindrical wave converter 14.

[0077] like Figure 3B As shown, the width T of the high-frequency cylindrical wave converter outlet can be calculated according to the selected high-frequency coupling upper limit. According to the line sound source formation conditions, T is less than or equal to half of the wavelength of the high-frequency coupling upper limit. If the selected high-frequency coupling upper limit is 20KHz, the corresponding high-frequency coupling upper limit wavelength is 17 mm, and accordingly, the width T of the high-frequency cylindrical wave converter outlet can be selected as 8 mm.

[0078] On this basis, the distance between the outer surface of the high-frequency phase plug 12 and the inner surface of the inner shell 36 of the intermediate frequency cylindrical wave converter, that is, the width of the waveguide channel of the high-frequency sound wave of the high-frequency cylindrical wave converter 14, can be calculated according to the trigonometric relationship.

[0079] Step 10: Design the outer shell of the intermediate frequency cylindrical wave converter according to the size of the intermediate frequency cylindrical wave converter inner shell and the intermediate frequency driver basin frame. Figure 3A and Figure 3BAs shown, the intermediate frequency cylindrical wave converter 8 is composed of an intermediate frequency cylindrical wave converter inner shell 36 and an intermediate frequency cylindrical wave converter outer shell 38. The size of the intermediate frequency driver basin limits the maximum outer size of the intermediate frequency cylindrical wave converter outer shell 38. The intermediate frequency cylindrical wave converter outer shell 38 contains the intermediate frequency cylindrical wave converter inner shell 36 and maintains a certain distance to form a wave channel of the intermediate frequency cylindrical wave converter 8. In addition, considering the shell thickness of the intermediate frequency cylindrical wave converter outer shell 38 (generally 5 mm), the intermediate frequency cylindrical wave converter outer shell 38 can be designed with reference to the intermediate frequency cylindrical wave converter inner shell 36.

[0080] In addition, in order to fix and connect various parts, the design of the connecting plate or connecting ribs between the high-frequency phase plug and the inner shell of the intermediate-frequency cylindrical wave converter can be further refined.

[0081] The coaxial cylindrical wave horn of the utility model has the following structural advantages:

[0082] 1. The high-frequency sound waves emitted by the high-frequency driver are converted from spherical waves to cylindrical waves through the high-frequency waveform converter.

[0083] 2. The intermediate frequency sound waves emitted by the intermediate frequency driver are converted from spherical waves to cylindrical waves through the intermediate frequency waveform converter.

[0084] 3. The high-frequency driver and its waveform converter are embedded in the intermediate-frequency waveform converter, and the acoustic axes of the two coincide, realizing a coaxial distribution structure, such as Figure 3A and Figure 3B shown.

[0085] 4. After the high-frequency and medium-frequency sound waves are converted into waveforms through their respective independent waveguide channels, they can share the same set of diffusion plates at the exit and diffuse into the air to achieve directivity control with the same characteristics.

[0086] In addition, the coaxial cylindrical wave horn of the utility model has the following advantages in design:

[0087] 1. Comparison of compression structure design to achieve equivalent transmission. In the field of sound reinforcement, the concept of compression ratio is similar to the concept of acceleration in physics, and is positively correlated with transmission efficiency. That is, the higher the compression ratio, the higher the efficiency of the sound reinforcement horn and the longer the transmission distance. In order to make the high-frequency and medium-frequency horns of this patented structure have the same efficiency, this patent introduces the concept of "compression in the same proportion" in the design of the medium-frequency driver compression structure, that is, according to the compression ratio of the selected high-frequency driver, the phase plug of the medium-frequency driver that matches it is designed to make its compression ratio consistent with that of the high-frequency driver.

[0088] 2. The coaxial structure + the shared diffusion horn design can achieve synchronous diffusion of the mid-frequency and high-frequency, greatly reducing the necking effect caused by coherence in the frequency overlap area, making the directivity more uniform.

[0089] 3. Because the IF phase plug is embedded in the IF driver, and the high-frequency driver is embedded in the IF phase plug, the distance between the IF driver and the high-frequency driver is compressed to the minimum. On the one hand, the high-frequency waveguide channel and the IF waveguide channel are both short, and the sound wave transmission attenuation is small. On the other hand, the length difference between the IF waveguide channel and the high-frequency waveguide channel is also minimal, which can realize the synchronous waveform conversion of the IF and high frequency, so that the IF and high-frequency sound waves form the same wave type propagation. The same wave transmission of the IF and high frequency is realized, the transmission efficiency is improved, and the "characteristic consistency" of the sound field is effectively optimized.

Claims

1. A coaxial cylindrical wave horn, comprising an intermediate frequency driver, an intermediate frequency phase plug, an intermediate frequency cylindrical wave converter, a high frequency driver, a high frequency phase plug, and a high frequency cylindrical wave converter sharing the same axis, characterized in that: The intermediate frequency phase plug is embedded in the intermediate frequency driver, and the high frequency driver is embedded in the intermediate frequency phase plug.

2. The coaxial cylindrical wave horn according to claim 1, characterized in that: The intermediate frequency phase plug includes three parts with the same axis. The first part is a cylinder, which is slidably matched with the center hole of the intermediate frequency driver for positioning. The second part is a cylinder, and the third part is a frustum. The second part and the third part match the diaphragm of the intermediate frequency driver and maintain a gap of 0.5-1 mm between the diaphragm.

3. The coaxial cylindrical wave horn according to claim 2, characterized in that: The frustum of the third part of the intermediate frequency phase plug is in the form of a shell, inside which there is a support structure for positioning the high frequency driver, the support structure is in the form of a cylinder and has the same axis as the frustum of the third part of the intermediate frequency phase plug.

4. The coaxial cylindrical wave horn according to claim 1, characterized in that: The high-frequency phase plug is in the shape of a modified cone, and the end of the high-frequency phase plug pointing to the high-frequency driver is in the shape of a cone. The end of the high-frequency phase plug pointing to the horn opening is a diameter line segment on the bottom circle of the cone and passing through the center of the bottom circle of the cone. Two planes pass through the diameter line segment, with the plane determined by the axis of the cone and the diameter line segment as the reference plane, are symmetrical to each other, and intersect with the cone.

5. The coaxial cylindrical wave horn according to claim 4, characterized in that: The included angle of the two planes is equal to the vertex angle of the cone, and the modified cone is formed by the cone and the two planes.

6. The coaxial cylindrical wave horn according to claim 1, characterized in that: The intermediate frequency cylindrical wave converter is composed of an intermediate frequency cylindrical wave converter inner shell and an intermediate frequency cylindrical wave converter outer shell. The intermediate frequency cylindrical wave converter inner shell is a modified frustum, and the top circular end of the frustum is connected to the intermediate frequency phase plug. The frustum is modified in that the frustum surface and the bottom circular part are connected to two planes. The two planes respectively pass through a line segment parallel to the bottom circle diameter. The distance between the line segment and the bottom circle diameter is the sum of the width of the high-frequency cylindrical wave converter opening and the thickness of the intermediate frequency cylindrical wave converter inner shell. The two planes are symmetrical to each other with the plane determined by the axis of the frustum and the bottom circle diameter as the reference plane. The modified frustum is surrounded by the frustum and the two planes. The difference in the sound wave propagation path on the surface of the modified frustum is less than one-fourth of the wavelength corresponding to the upper frequency limit adapted by the intermediate frequency driver.

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