A controllable wavefront sinusoidal smooth equi-path high frequency waveguide design method

Abstract

The application discloses a controllable wave front sinusoidal smooth equal-path high-frequency waveguide design method, and the method comprises the following steps: determining the target form of the outlet wave front according to the directivity requirement of a linear array, introducing a central path deviation amount, establishing a target acoustic length distribution function of all paths, establishing a three-dimensional parameter equation group of an inner core and an outer shell, and deriving the actual arc length integral of the inner core and the outer shell; taking the calculation result of the target acoustic length distribution function as a target value, combining the actual arc length integral of the inner core and the outer shell, and respectively solving the sinusoidal amplitudes of the inner core path and the outer shell path; based on the sinusoidal amplitudes of the inner core path and the outer shell path, generating an inner core space point cloud curve file and an outer shell space point cloud curve file, and importing a three-dimensional design software to perform engineering entity modeling. The application realizes the physical equidistance of the inner and outer channels of the acoustic waveguide, eliminates high-frequency phase distortion, and suppresses airflow turbulence noise.

Description

Technical Field

[0001] This invention relates to the field of acoustic waveguide design technology, and more specifically, to a method for designing a controllable wavefront sinusoidal smooth equal-path high-frequency waveguide. Background Technology

[0002] Classical linear array high-frequency waveguides (such as DOSC horns) are designed to convert cylindrical or spherical waves from a compression driver throat into planar rectangular wavefronts. However, in engineering practice, traditional designs suffer from the following technical drawbacks:

[0003] 1. Acoustic Refraction Caused by Corner Joints: Traditional DOSC horns often use geometric hard joints (corner joints) to construct the waveguide cavity. This design easily generates acoustic refraction at the corners, exciting higher-order modes. The presence of higher-order modes leads to complex interference phenomena of sound waves inside the waveguide, resulting in non-uniformity of the exit wavefront and seriously affecting the consistency of sound field coverage and sound quality performance.

[0004] II. Unequal Acoustic Path Lengths Due to CAD Surface Offset: When designing waveguide shells, many engineers are accustomed to offsetting the designed inner wall surface along the normal direction by a specific thickness in CAD software to generate the shell. From the perspective of acoustic propagation mechanisms, this modeling method has a fundamental flaw. Due to the existence of spatial curvature, the physical length of the offset outer wall curve will inevitably change. This causes a phase difference between the wavefronts propagating closer to the outer wall and those propagating closer to the inner wall within the same channel. This results in a severe comb-like filtering effect at the crossover point and higher frequency bands, causing irregular fluctuations in frequency response and deterioration in timbre.

[0005] Third, lack of active wavefront control capability: In existing technologies, the shape of the exit wavefront is usually determined by a fixed geometry, which cannot be flexibly adjusted according to the directional requirements of the actual application scenario. When it is necessary to expand the vertical diffusion angle or achieve a specific sound field coverage mode, traditional designs lack effective active wavefront control methods, making it difficult to achieve customized wavefront shapes such as micro-convex or micro-concave.

[0006] Fourth, the lack of a complete closed-loop solution from theory to manufacturing: Existing waveguide design methods often remain at the level of theoretical calculation or empirical design, lacking a complete technical path to directly transform rigorous mathematical integral constraints into a manufacturable physical model. Designers need to manually convert data between multiple software programs, which can easily introduce errors and makes it difficult to ensure that the acoustic performance of the theoretical design is accurately reproduced in actual manufacturing.

[0007] The aforementioned defects in existing technologies limit the improvement of the acoustic performance of high-end linear array high-frequency waveguides. Summary of the Invention

[0008] To overcome the technical problems of unequal acoustic path length, severe high-frequency phase distortion, uncontrollable wavefront, and lack of a complete design and manufacturing closed loop in existing technologies, this invention provides a controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method. This method achieves physical equidistance of the inner and outer channels of the acoustic waveguide, eliminates high-frequency phase distortion, and suppresses airflow turbulence noise. It provides a complete closed-loop solution from theoretical calculation to CAD manufacturing for the core waveguide development of modern high-end line array loudspeakers.

[0009] The technical solution of this invention is as follows:

[0010] This invention provides a method for designing a controllable wavefront sinusoidal smooth equal-path high-frequency waveguide, comprising:

[0011] Step S1: Based on the directivity requirements of the linear array, determine the target shape of the exit wavefront, introduce the center path deviation, and establish the target acoustic length distribution function for all paths.

[0012] Step S2: Establish a three-dimensional parametric equation system for the inner core and the outer shell, and differentiate to obtain the integral of the actual arc length of the inner core and the outer shell;

[0013] Step S3: Using the calculation result of the target acoustic length distribution function as the target value, and combining the actual arc length integrals of the inner core and the outer shell, the sinusoidal amplitudes of the inner core path and the outer shell path are solved respectively.

[0014] Step S4: Based on the sinusoidal amplitude of the inner core path and the outer shell path, generate the inner core spatial point cloud curve file and the outer shell spatial point cloud curve file, and import them into 3D design software for engineering solid modeling.

[0015] As a preferred embodiment of the present invention, the target acoustic length distribution function is:

[0016] ;

[0017] in, For the target acoustic length, The length of the reference straight line at the outermost boundary. Where W is the center path deviation and W is the exit width. Let x be the x-coordinate of any point at the exit. .

[0018] As a preferred embodiment of the present invention, when When =0, a plane wave is formed; when When <0, a convex wavefront is formed; when When the value is greater than 0, a concave wavefront is formed.

[0019] As a preferred embodiment of the present invention, the three-dimensional parametric equations of the inner core are as follows:

[0020] ;

[0021] ;

[0022] ;

[0023] Where H is the horn height, For parameterized variables, , The amplitude of the sinusoidal vibration along the inner core path.

[0024] As a preferred embodiment of the present invention, the three-dimensional parametric equations of the outer shell are as follows:

[0025] ;

[0026] ;

[0027] ;

[0028] in, The x-coordinate of the starting point , The starting point is the vertical coordinate. R is the radius of the throat of the high-pitched driver. The width of the outlet cross section. The amplitude of the sinusoidal vibration along the outer shell path.

[0029] As a preferred embodiment of the present invention, the formula for calculating the integral of the actual arc length is as follows:

[0030] ;

[0031] ;

[0032] in, , , The three-dimensional parametric equations of the inner core The derivative of , , The three-dimensional parametric equations for the shell The derivative of .

[0033] As a preferred embodiment of the present invention, in step S3, the sinusoidal amplitudes of the inner core path and the outer shell path are solved using a numerical root-finding algorithm, so that... = .

[0034] As a preferred embodiment of the present invention, the engineering solid modeling includes:

[0035] Import skeleton curves: Import the generated inner core space point cloud curve file and the outer shell space point cloud curve file into the 3D design software;

[0036] Constructing acoustic double walls: Using the boundary blending tool, pick the inner core skeleton lines in sequence to generate the inner wall surface, and pick the outer shell skeleton lines in sequence to generate the outer wall surface;

[0037] Closed diffusion boundary: The boundary blending tool is used to connect the outermost edges of the inner and outer walls to generate an acoustic lateral boundary;

[0038] Solidified acoustic air cavity: After sealing the throat and outlet, and merging all surface groups, solidification is performed to obtain a complete internal acoustic fluid solid;

[0039] Physical shell generation: Create a speaker material entity that encloses the internal acoustic fluid entity on the outside, and use Boolean operations to remove the internal air domain material to obtain the final manufactured part.

[0040] As a preferred embodiment of the present invention, in the solidified acoustic air cavity, the throat and the outlet are sealed using a filling tool or a planar tool, and all face groups are merged using a merging tool.

[0041] As a preferred embodiment of the present invention, the engineering solid modeling further includes:

[0042] Acoustic simulation verification: The generated internal acoustic fluid entity is output to acoustic simulation software for finite element simulation to verify the flatness and phase consistency of the exit wavefront.

[0043] According to the above-described solution, the beneficial effects of this invention are as follows:

[0044] This invention establishes independent parameterized equations for the inner core and outer shell through rigorous mathematical integral constraints, and ensures that the arc lengths of the inner and outer walls are equal through a numerical root-finding algorithm. This achieves physical equidistance between the inner and outer channels of the acoustic waveguide, effectively solving the problem of unequal acoustic path lengths caused by traditional CAD surface offset methods. At the same time, since the acoustic lengths of all propagation paths are strictly consistent, the sound waves maintain perfect phase consistency at the exit, eliminating high-frequency phase distortion and comb-tooth filtering effects caused by path differences, and significantly improving the flatness of the high-frequency response and sound quality. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating a controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to an embodiment of the present invention.

[0046] Figure 2 for Figure 1A schematic diagram illustrating the specific process of engineering entity modeling in step S4;

[0047] Figure 3 This is a skeleton curve diagram generated after importing the inner core space point cloud curve file and the outer shell space point cloud curve file into PTC CREO in one embodiment of the present invention;

[0048] Figure 4 This is a double-walled surface diagram generated after constructing acoustic double walls and a closed diffusion boundary in one embodiment of the present invention;

[0049] Figure 5 This is a solid diagram of the internal acoustic fluid generated after the solidification of the acoustic air cavity in one embodiment of the present invention;

[0050] Figure 6 This is a simulated sound pressure diagram after the internal acoustic fluid entity outputs to COMSOL for finite element simulation in one embodiment of the present invention. Detailed Implementation

[0051] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0052] It should be noted that the terms "comprising" and "having," and any variations thereof, in the specification and claims of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0053] like Figure 1 As shown, one embodiment of the present invention provides a method for designing a controllable wavefront sinusoidal smooth equal-path high-frequency waveguide, comprising the following steps:

[0054] Step S1: Based on the directivity requirements of the linear array, determine the target shape of the exit wavefront and introduce the center path deviation to establish the target acoustic length distribution function for all paths. The details are as follows:

[0055] In practical line array loudspeaker design, the exit wavefront is not limited to a planar shape; it often needs to be customized into a slightly convex or slightly concave shape based on the acoustic characteristics of the site and coverage requirements. Let the exit width be W, and the x-coordinate of any point at the exit be... Introducing center path deviation As a parameter for controlling the shape of the wavefront:

[0056] when When the center path equals the edge path (=0), a plane wave is formed. This mode is suitable for standard linear array applications where sound waves are required to radiate in the form of plane waves to achieve uniform sound field coverage.

[0057] when When the distance is less than 0 (convex wavefront mode), the center path is shorter, the center sound wave arrives earlier, and the wavefront bulges outward, forming a convex wavefront. This mode is beneficial for increasing the vertical diffusion angle and is suitable for applications requiring a wide coverage area, such as long-distance projection in large stadiums.

[0058] when When the value is >0 (concave wavefront mode), the center path is longer, meaning the center sound wave arrives later, and the wavefront is concave inward, forming a concave wavefront. This mode is beneficial for concentrating sound energy and improving directivity, making it suitable for applications requiring precise sound beam control, such as near-field coverage in theaters.

[0059] To ensure a smooth wavefront space and avoid abrupt changes between adjacent paths, the target acoustic length of all paths is... It adopts a quadratic parabolic distribution:

[0060] ;

[0061] in, This is the reference straight-line length of the outermost boundary. This target acoustic length distribution function ensures that the path length variation from the center to the edge is continuous and smooth, avoiding step-like discontinuities in the wavefront shape, thus guaranteeing phase consistency at the sound wave exit. Furthermore, the target acoustic length is an absolute law followed by both the inner core and the outer shell.

[0062] Step S2: Establish the three-dimensional parametric equations for the inner core and outer shell, and differentiate them to obtain the integrals of the actual arc lengths of the inner core and outer shell. The details are as follows:

[0063] Let the horn height be H, and the parameterized variable be... .

[0064] The inner core topology is wedge-shaped, with the starting point converging at the origin (0, 0, 0), corresponding to the center point of the compression actuator throat; the ending point is located at the outlet centerline ( ,0,H).

[0065] The three-dimensional parametric equations of the inner core are as follows:

[0066] ;

[0067] ;

[0068] ;

[0069] in, The sinusoidal amplitude of the inner core path; This indicates that the inner core expands linearly from the origin to the exit position in the horizontal direction (width direction). ; This indicates that the inner core extends linearly from the throat to the outlet in the vertical direction (height direction), with a height of... ; This is a sinusoidal half-cycle smooth curve (Sine-Profile), serving as the transition curve of the inner core in the depth direction (bulge direction). This curve in u... 0 and u All zeros at 1 location ( 0), in u The maximum value is reached at 0.5. The introduction of the sine function ensures that the slope of the tangent at the start and end points of the curve is zero, achieving G2 / G3 continuity (tangent continuity), thus guaranteeing excellent aerodynamic smoothness and effectively suppressing airflow turbulence noise.

[0070] The housing topology is a circular-to-square transition, achieving a topological mapping from a circular throat section to a rectangular outlet section. For a standard 25mm diameter tweeter, its throat radius R = 12.5mm, and the throat section is semi-circular; the outlet cross-sectional width is... Starting point x-coordinate This achieves a proportional mapping from the outlet width W to the throat radius R, with the starting point ordinate... The outline of the semi-circular throat is described to ensure that the housing at the throat perfectly matches the circular outlet of the driver.

[0071] The three-dimensional parametric equations of the outer shell are:

[0072] ;

[0073] ;

[0074] ;

[0075] in, The amplitude of the sinusoidal vibration along the outer shell path; This indicates that the outer shell is positioned horizontally from the throat position. Linear transition to the exit position ; This indicates that the outer shell extends linearly from the throat to the outlet in the vertical direction (height direction), with a height of H; It consists of three parts: Indicates the initial depth at the throat. This represents the linear depth change from the throat to the outlet. This represents the smooth transition term of the sinusoidal half-cycle, similar to the inner core, ensuring aerodynamic smoothness.

[0076] The actual spatial arc length between the inner core and outer shell is a key physical quantity for evaluating acoustic propagation time. According to differential geometry, the actual spatial arc length between the inner core and outer shell is obtained by differentiating and integrating their three-dimensional parametric equations:

[0077] ;

[0078] ;

[0079] in, , , The three-dimensional parametric equations of the inner core The derivative of , , The three-dimensional parametric equations for the shell The derivative of .

[0080] Step S3: Using the calculation result of the target acoustic length distribution function as the target value, and combining the actual arc length integrals of the inner core and outer shell, the sinusoidal amplitudes of the inner core path and the outer shell path are solved respectively.

[0081] Specifically, using numerical root-finding algorithms (such as the fzero function in MATLAB), the sinusoidal amplitudes of the inner core path and the outer shell path are solved separately, so that... = This is a nonlinear equation solving problem. For each exit location... Each of them requires an independent solution to a set of problems. , The solution process is as follows:

[0082] 1) Set the target acoustic length ;

[0083] 2) For the inner core, with As variables, calculate through numerical integration Using fzero to solve makes of value;

[0084] 3) Regarding the outer casing, with As variables, calculate through numerical integration Using fzero to solve makes of value;

[0085] 4) Verification Ensure that the arc lengths of the inner and outer walls are equal.

[0086] This constraint allows for nanosecond-level synchronization of sound wave propagation time in channels with significantly different geometric shapes, such as wedge-shaped inner cores and round-to-square outer shells.

[0087] Step S4: Based on the sinusoidal amplitude of the inner core path and the outer shell path, generate the inner core spatial point cloud curve file and the outer shell spatial point cloud curve file, and import them into 3D design software for engineering solid modeling.

[0088] Specifically, such as Figure 2 As shown, using PTC CREO as an example, the steps for creating a solid model of an engineering project are illustrated:

[0089] Step S41: Import Skeleton Curves: Using PTC CREO's baseline, curve, and file import functions, import the generated inner core space point cloud curve file (e.g., InnerCore.ibl) and outer shell space point cloud curve file (e.g., OuterShell.ibl) into PTC CREO. The imported skeleton curves are as follows: Figure 3 As shown, the inner core spatial point cloud curve file and the outer shell spatial point cloud curve file respectively contain the inner core and outer shell at multiple exit locations. The three-dimensional spatial curve at that location.

[0090] Step S42: Constructing the Acoustic Double Walls: Using PTC CREO's Boundary Blend tool, sequentially pick the inner core skeleton lines to generate a G2 / G3 continuous inner wall surface, and sequentially pick the outer shell skeleton lines to generate a G2 / G3 continuous outer wall surface. G2 continuity indicates curvature continuity, and G3 continuity indicates curvature change rate continuity. This higher-order continuity ensures that the reflection of sound waves on the wall surface is smooth and does not produce additional acoustic distortion.

[0091] Step S43, Close the diffusion boundary: Use the boundary blending tool again to connect the outermost edges of the inner and outer walls, generating a double-walled surface as shown. Figure 4 As shown, the flat side profile generated here is the acoustic lateral boundary that determines the horn's horizontal coverage. The geometry of this boundary directly affects the horn's beam diffusion characteristics in the horizontal direction.

[0092] Step S44: Solidify the acoustic air cavity: Use the fill tool or planar tool of PTC CREO to close the circular throat and the rectangular mouth. Use the merge tool to merge all face groups. After merging all face groups, solidify them to obtain a complete internal acoustic fluid entity, such as... Figure 5As shown, the internal acoustic fluid entity is the actual spatial channel for sound wave propagation. It can be directly output to acoustic simulation software such as COMSOL for finite element method (FEA / BEM) simulation to verify the flatness and phase consistency of the exit wavefront. Figure 6 The simulated sound pressure diagram after finite element simulation of the internal acoustic fluid entity output to COMSOL shows that the outlet is almost close to a plane wave.

[0093] Step S45, Physical Shell Generation: Create a speaker material entity (such as a resin or die-cast aluminum shell) that encloses the internal acoustic fluid entity. Use Boolean operations to remove the internal air domain material to obtain the final manufactured part with perfectly sinusoidal smooth path channels. This final manufactured part can be directly used for CNC machining or 3D printing.

[0094] This embodiment of the controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method establishes independent parameterized equations for the inner core and outer shell through rigorous mathematical integral constraints. A numerical root-finding algorithm ensures that the arc lengths of the inner and outer walls are equal, achieving physical equidistance between the inner and outer acoustic waveguide channels. This effectively solves the problem of unequal acoustic path lengths caused by traditional CAD surface offset methods. Because the acoustic lengths of all propagation paths are strictly consistent, the sound wave maintains perfect phase consistency at the exit point, eliminating high-frequency phase distortion and comb-tooth filtering effects caused by path differences, significantly improving the flatness of the high-frequency response and sound quality. A sinusoidal half-cycle smooth curve is introduced as a transition, replacing the traditional folding... Corner splicing ensures excellent aerodynamic smoothness; by introducing center path deviation and target acoustic length with quadratic parabolic distribution, active control of the exit wavefront shape is achieved. Plane wave, convex wavefront, or concave wavefront can be flexibly customized according to actual application needs to meet the directivity requirements of different scenarios; a complete closed-loop solution is provided, from theoretical calculation (numerical root finding) to CAD modeling (CREO physicalization) to acoustic simulation (COMSOL verification). Designers can directly import the point cloud curves generated by numerical calculation into 3D design software without manual adjustment, ensuring that the acoustic performance of theoretical design is accurately reproduced in actual manufacturing.

[0095] Furthermore, although the operations of the method of the present invention are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0096] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

[0097] The present invention has been described above with reference to the accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A method for designing a controllable wavefront sinusoidal smooth equal-path high-frequency waveguide, characterized in that, include: Step S1: Based on the directivity requirements of the linear array, determine the target shape of the exit wavefront, introduce the center path deviation, and establish the target acoustic length distribution function for all paths. Step S2: Establish a three-dimensional parametric equation system for the inner core and the outer shell, and differentiate to obtain the integral of the actual arc length of the inner core and the outer shell; Step S3: Using the calculation result of the target acoustic length distribution function as the target value, and combining the actual arc length integrals of the inner core and the outer shell, the sinusoidal amplitudes of the inner core path and the outer shell path are solved respectively. Step S4: Based on the sinusoidal amplitude of the inner core path and the outer shell path, generate the inner core spatial point cloud curve file and the outer shell spatial point cloud curve file, and import them into 3D design software for engineering solid modeling.

2. The controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to claim 1, characterized in that, The target acoustic length distribution function is: ； in, For the target acoustic length, The length of the reference straight line at the outermost boundary. Where W is the center path deviation and W is the exit width. Let x be the x-coordinate of any point at the exit. .

3. The controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to claim 2, characterized in that, when When =0, a plane wave is formed; when When <0, a convex wavefront is formed; when When the value is greater than 0, a concave wavefront is formed.

4. The controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to claim 2, characterized in that, The three-dimensional parametric equations of the inner core are as follows: ； ； ； Where H is the horn height, For parameterized variables, , The amplitude of the sinusoidal vibration along the inner core path.

5. The controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to claim 4, characterized in that, The three-dimensional parametric equations of the outer shell are as follows: ； ； ； in, The x-coordinate of the starting point , The starting point is the vertical coordinate. R is the radius of the throat of the high-pitched driver. The width of the outlet cross section. The amplitude of the sinusoidal vibration along the outer shell path.

6. The controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to claim 5, characterized in that, The formula for calculating the integral of the actual arc length is as follows: ； ； in, , , The three-dimensional parametric equations of the inner core The derivative of , , The three-dimensional parametric equations for the shell The derivative of .

7. The controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to claim 6, characterized in that, In step S3, the sinusoidal amplitudes of the inner core path and the outer shell path are solved using a numerical root-finding algorithm, so that... = .

8. The controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to claim 1, characterized in that, The engineering entity modeling includes: Import skeleton curves: Import the generated inner core space point cloud curve file and the outer shell space point cloud curve file into the 3D design software; Constructing acoustic double walls: Using the boundary blending tool, pick the inner core skeleton lines in sequence to generate the inner wall surface, and pick the outer shell skeleton lines in sequence to generate the outer wall surface; Closed diffusion boundary: The boundary blending tool is used to connect the outermost edges of the inner and outer walls to generate an acoustic lateral boundary; Solidified acoustic air cavity: After sealing the throat and outlet, and merging all surface groups, solidification is performed to obtain a complete internal acoustic fluid solid; Physical shell generation: Create a speaker material entity that encloses the internal acoustic fluid entity on the outside, and use Boolean operations to remove the internal air domain material to obtain the final manufactured part.

9. The controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to claim 8, characterized in that, In the solidified acoustic air cavity, the throat and the outlet are sealed using a filling tool or a planar tool, and all face groups are merged using a merging tool.

10. The controllable wavefront sinusoidal smooth equal-path high-frequency waveguide design method according to claim 8, characterized in that, The engineering physical modeling also includes: Acoustic simulation verification: The generated internal acoustic fluid entity is output to acoustic simulation software for finite element simulation to verify the flatness and phase consistency of the exit wavefront.

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