Dual sound source wave front non-common cavity horizontal coupling tweeter waveguide

Abstract

The application provides a double-sound-source wave front non-common-cavity horizontal coupling tweeter waveguide, which is Y-shaped and comprises two horizontally arranged waveguide channels; the first waveguide channel is used for connecting a spherical wave tweeter driver and is composed of a first channel, a first reflecting surface, a second channel, a second reflecting surface and a third channel connected in sequence; the first channel is a parabolic surface; the first reflecting surface is an elliptical surface; the second channel is a hyperboloid; the second reflecting surface is a rectangular surface; and the third channel is a rectangular surface; the second waveguide channel is used for connecting a plane wave sound source and is composed of a fourth channel, a third reflecting surface, a fifth channel, a fourth reflecting surface and a sixth channel connected in sequence; and each channel and reflecting surface is a rectangular surface. The waveguide of the application enables two or more sound sources to be coupled in a horizontal position without a common cavity and converts sound waves into a wave front in the shape of a plane wave without acoustic interference.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of acoustic waveguide, especially for the waveguide of the sound source wave front of multiple identical or different drivers of loudspeaker is not shared cavity horizontal vertical direction coupling radiation. BACKGROUND

[0002] With the improvement of the requirement of loudspeaker playback quality in the field of sound amplification, the sound pressure requirement of the far and near field range is consistent and uniform, and the linear sound source with better sound amplification performance than traditional point sound source is gradually popularized. The linear array loudspeaker system composed of linear sound source diffuses, which has the characteristics of small vertical angle of single loudspeaker, effectively solves the sound interference problem between loudspeakers, and slow sound pressure attenuation and long transmission distance of linear array loudspeaker system.

[0003] As shown in Figure 1 , point sound source 2 refers to the way of spherical wave diffusion of point sound source, which has the characteristics of large horizontal and vertical coverage angle and fast sound pressure attenuation. For spherical wave, the sound intensity at any distance from the sound source is inversely proportional to the square of the distance. As shown in FIG. P1, when the sound source distance increases from R to R2, i.e. twice R, the area of wave front increases from A to 4A, and the sound intensity decreases to 1 / 4. The sound pressure level decreases by 6dB when the distance R increases by one time.

[0004] As shown in Figure 2 , linear sound source 4 is composed of multiple cylindrical wave sound source loudspeaker systems. The high-frequency driver is generally a band-shaped driver close to plane wave, such as the loudspeaker disclosed in US2007 / 0160233A1. Or it is converted into a cylindrical wave sound source similar to plane wave through a related waveguide device, such as the acoustic waveguide disclosed in US5163167A. The vertical high-frequency part of the linear sound source loudspeaker has very narrow pointing angle, and the vertical pointing angle is generally about 5-10 degrees. The energy of cylindrical wave decreases by 3dB when the sound source distance increases by one time. The wave front generated by linear sound source 4 is coaxial cylindrical wave, which is called cylindrical wave. It is assumed that there is an infinite long uniform linear sound source in an infinite uniform medium, and the wave generated by the linear sound source is ideal cylindrical sound wave. In cylindrical sound wave, the amplitude of sound pressure is uniformly distributed along the axial direction, and inversely proportional to the square root of the distance from the axis along the radial direction. The radial sound intensity is inversely proportional to the distance from the axis. Figure 2 As shown in FIG. P2, when the sound source distance increases from R to R2, i.e. twice R, the area of wave front increases from A to 2A, and the sound intensity decreases to 1 / 2. Due to the small transmission attenuation characteristic of linear sound source loudspeaker, it can have a longer sound amplification efficiency. The high-frequency coupling characteristic is good, which can reduce the distortion caused by interference and is beneficial to high-quality sound amplification. The directivity control is better when the whole string of linear sound source loudspeakers works, and the more the number in the vertical direction, the lower the controllable frequency of directivity.

[0005] Following the market needs, various manufacturers designed based on the line source array loudspeaker products and applications to professional sound amplification. For example, US7965857B2, the patent is US2007 / 0160233A1 of the same family. The patent discloses a tape high frequency driver suitable for line source sound amplification applications. According to the description and drawings of US2007 / 0160233A1, the loudspeaker includes two identical metal housings, the metal housings have 2 extended slots or sound channels, so that the sound produced by the loudspeaker is transmitted outward. A horn can be connected to the loudspeaker, the horn provides a gradually widening wave front.

[0006] In addition, there are also many manufacturers designed based on the compression driver design close to the shape of the cylindrical wave conversion of the horn waveguide. The earliest with France Heil Christian as the representative of the patent US5163167A as the representative. The description and drawings of US5163167A indicate that the waveguide has 3 elements, two elements are symmetrical along the vertical plane and include a shell fixed to the inner core, each shell includes a rear plate and a front plate and is connected by a center plate, the front plate has an opening, the shell covers the inner core and has a gap. The patent discloses a sound wave channel slot composed of a parabolic surface and a hyperbolic surface at the circular outlet of the compression driver, and a rectangular outlet, and the time of the wave front passing through the surface of the phase plug is approximately equal, that is, the path difference δ between the sound wave path of the compression driver with a circular hole in the waveguide and the wave front of the rectangular outlet of the waveguide is allowed to be: δ≤λ / 4, (λ is the wavelength of the highest usable frequency of the design target) the error is less than or equal to one quarter of the highest working frequency, of course, it is not absolutely the same. Only the error is small enough to be within the acceptable range of the product design working frequency.

[0007] The above two linear array line sources can only realize the vertical array combination of a single sound source loudspeaker, as shown in Fig. 13 of US5163167A. Moreover, the two vertical sound sources must work in the same frequency range, otherwise continuous coherent sound waves cannot be generated. The size of the rectangular opening of a qualified line source is less than or equal to the wavelength of the highest frequency of the design target, that is: W≤λ. For example, the rectangular outlet width of the tape high frequency in the patent US2007 / 0160233A1 is 18mm, and the rectangular outlet width of the waveguide in the patent US5163167A is 18mm. According to W≤λ, the upper limit of the working frequency is calculated to be 19KHz.

[0008] In order to meet the coupling conditions, the center distance M of the adjacent two sound sources should be less than or equal to one half of the wavelength of the upper limit frequency, that is: M≤λ / 2. Therefore, when the coupling upper limit frequency Fh of the high frequency unit is 18KHz, the sound source center distance M can be calculated according to Fh = 18KHz, sound speed V0 = 343m / s, M≤9.5mm.

[0009] As shown in Figure 3A When two ribbon tweeters 6 are horizontally arranged, the sound source spacing M is 109 mm, and the corresponding coupling upper limit frequency Fh = 3155 Hz. Figure 3A The interference of two ribbon tweeters is shown. The straight line indicates that the frequency less than 3155 Hz is propagated in the form of a plane wave, and the comb filter interference starts to appear when the frequency is greater than 3155 Hz.

[0010] As shown in Figure 3B When two compression tweeters 8 are horizontally arranged via a waveguide 10 as in the US patent 5163167A, the sound source center spacing M is 18 mm, and the corresponding coupling upper limit frequency Fh = 9555 Hz, Figure 3B The interference of two waveguides is shown. The straight line indicates that the frequency less than 9555 Hz is propagated in the form of a plane wave, and the interference starts to appear when the frequency is greater than 9555 Hz.

[0011] It can be seen that due to the physical structure, neither the ribbon tweeter nor the cylindrical wave conversion device represented by the French Heil Christian can achieve perfect coupling of multiple drivers in the horizontal direction. The expected available frequency is less than 10 kHz, which is much smaller than 18 kHz when a single driver is vertically coupled. SUMMARY

[0012] In view of the problem that the current industry linear sound source technology cannot be perfectly coupled in the horizontal plane, the present application achieves perfect coupling in the horizontal plane while achieving the following purposes:

[0013] Another object of the present application is to provide a periscope type reflection barrel to make two or more sound sources (tweeters or mid-range) not in the same cavity in the horizontal position, and to convert the sound wave into a plane wave shape without acoustic interference.

[0014] Another object of the present application is to provide a method for increasing the sound pressure level output, in which multiple drivers in the same frequency range are coupled in the same cavity in the waveguide, and the maximum sound pressure level of the single driver vertically coupled in the waveguide according to the existing technology in the current industry is increased by ≥6 dB.

[0015] Another object of the present application is to provide a method that allows multiple drivers in the same frequency range to produce a common wave coupling in the same wave in the horizontal position without acoustic interference.

[0016] Another object of the present invention is to provide a method that allows multiple driver sound sources operating in different frequency ranges to produce common coupling in the same horizontal position wave front without acoustic interference.

[0017] Another object of the present invention is to provide a method that produces one or more wave fronts in one or more frequency ranges within a sound box, which couples the sound waves of the same frequency range in the line array hanging adjacent sound boxes and has no acoustic interference.

[0018] The present invention provides a dual sound source wave front non-coupled horizontal coupling tweeter waveguide, which is Y-shaped and includes two waveguide channels arranged horizontally, the first waveguide channel is used to connect a spherical wave tweeter driver, and the first waveguide channel is composed of a first channel, a first reflecting surface, a second channel, a second reflecting surface, and a third channel connected in sequence, the first channel is parabolic, the first reflecting surface is elliptical, the second channel is hyperbolic, the second reflecting surface is rectangular, and the third channel is rectangular, and the second waveguide channel is used to connect a plane wave sound source, and the second waveguide channel is composed of a fourth channel, a third reflecting surface, a fifth channel, a fourth reflecting surface, and a sixth channel connected in sequence, and the fourth channel, the third reflecting surface, the fifth channel, the fourth reflecting surface, and the sixth channel are all rectangular.

[0019] As an improvement, the first channel is composed of a pair of mutually fitted convex and concave parabolic surfaces, the first channel is composed of the space between the two parabolic surfaces, the concave parabolic surface has a parabolic line at the end of the parabolic cross section as a part of the parabolic line of the elliptical cross section of the first reflecting surface, the elliptical cross section of the first reflecting surface has a parabolic line at the end of the cross section as a part of the parabolic line of the hyperbolic cross section of the second channel, the convex parabolic surface is part of a right circular cone with a vertex angle less than or equal to 90°, and the parabolic line at the end of the parabolic cross section is a part of the parabolic line of the hyperbolic cross section of the second channel.

[0020] As an improvement, the second channel is connected to the first channel through the first reflecting surface, the second channel is connected to the third channel through the second reflecting surface, the second channel is located between the first reflecting surface and the second reflecting surface, the first reflecting surface is located at the end of the first channel, the first reflecting surface is an elliptical reflecting surface, the second reflecting surface is a rectangular plane, in the horizontal cross-sectional view, the second channel is composed of mutually parallel inner and outer walls, the inner wall of the second channel is connected to the first reflecting surface at the entrance end, the outer wall of the second channel is connected to the convex parabolic surface at the entrance end, and the outer wall of the second channel is connected to the second reflecting surface at the exit end.

[0021] As an improvement, the sound wave rays pass through the first channel, the first reflecting surface, the second channel, the second reflecting surface, and the third channel, and the sound wave rays passing through the first reflecting surface and the second reflecting surface satisfy the reflection law, i.e. the incident angle is equal to the reflection angle: θi1=θr1=θi2=θr2, and the path difference δ of the sound wave passing through the first waveguide channel is: δ≤λ / 4.

[0022] As an improvement, in the horizontal sectional view, the third channel is composed of a third channel inner wall and a third channel outer wall, the third channel outer wall is connected with the second reflecting surface at the entrance end, the third channel inner wall is connected with the second channel inner wall at the entrance end, the center line of the first channel is parallel to the third channel outer wall, the third channel inner wall is in the shape of a broken line, the entrance section of the third channel inner wall is parallel to the third channel outer wall, and the exit section of the third channel inner wall is connected with the entrance section of the third channel inner wall at one end and connected with the exit of the third channel at the other end.

[0023] As an improvement, in the horizontal sectional view, the fourth channel is composed of a fourth channel inner wall and a fourth channel outer wall, the fifth channel is composed of a fifth channel inner wall and a fifth channel outer wall, the sixth channel is composed of a sixth channel inner wall and a sixth channel outer wall, the fourth channel inner wall, the third reflecting surface, the fifth channel inner wall, and the sixth channel inner wall are sequentially connected to form the inner wall of the second waveguide channel, and the fourth channel outer wall, the fifth channel outer wall, the fourth reflecting surface, and the sixth channel outer wall are sequentially connected to form the outer wall of the second waveguide channel.

[0024] As an improvement, in the horizontal sectional view, the fourth channel inner wall is parallel to the fourth channel outer wall and has the same length, the fifth channel inner wall is parallel to the fifth channel outer wall and has the same length, the third reflecting surface is parallel to the fourth reflecting surface and has the same length, the sixth channel outer wall is parallel to the fourth channel inner wall, the sixth channel inner wall is in the shape of a broken line, the entrance section of the sixth channel inner wall is parallel to the sixth channel outer wall, and the exit section of the sixth channel inner wall is connected with the entrance section of the sixth channel inner wall at one end and connected with the exit of the sixth channel at the other end.

[0025] As an improvement, the sound wave rays pass through the fourth channel, the third reflecting surface, the fifth channel, the fourth reflecting surface, and the sixth channel, and the sound wave rays passing through the third reflecting surface and the fourth reflecting surface satisfy the reflection law, i.e. the incident angle is equal to the reflection angle: θi3=θr3=θi4=θr4, and the path difference δ of the sound wave passing through the second waveguide channel is: δ≤λ / 4.

[0026] The application further provides a high-pitched horn, which comprises the aforementioned double-sound-source wave front non-common-cavity horizontal coupling high-pitched waveguide and two high-pitched drivers installed at the entrance end of the high-pitched waveguide channel.

[0027] The application further provides a sound box, which comprises the aforementioned high-pitched horn, two medium-low pitched horns horizontally symmetrically arranged on both sides of the high-pitched horn, and a box body. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Schematic diagram of a point source and a spherical wave.

[0029] Figure 2 Schematic diagram of a line source and a cylindrical wave.

[0030] Figure 3A Schematic diagram of two ribbon tweeters horizontally coupled.

[0031] Figure 3B Schematic diagram of two tweeters horizontally coupled through a conventional waveguide.

[0032] Figure 3C Schematic diagram of the waveguide of the present invention and a tweeter horizontally coupled.

[0033] Figure 4 Schematic diagram of the cross-section of the tweeter horn of the present invention on a horizontal plane through the center of the waveguide.

[0034] Figure 5A Schematic diagram of the inner wall of the first waveguide channel of the waveguide of the present invention.

[0035] Figure 5B Schematic diagram of the outer wall of the first waveguide channel of the waveguide of the present invention.

[0036] Figure 5C Schematic diagram of the ray path of sound waves in the first waveguide channel.

[0037] Figure 5D Schematic diagram of the ray path of sound waves in the second waveguide channel.

[0038] Figure 6A Schematic diagram of the horizontal cross-section of the waveguide of the present invention applied to a sound box design.

[0039] Figure 6B Schematic diagram of the front view of the waveguide of the present invention applied to a sound box design.

[0040] Figure 7 Schematic diagram of the test curve comparison of the waveguide of the present invention and the prior art under the same test conditions.

[0041] Figure 8A Horizontal 3D directivity diagram of the waveguide of the prior art.

[0042] Figure 8B Vertical 3D directivity diagram of the waveguide of the prior art.

[0043] Figure 9A Horizontal 3D directivity diagram of the waveguide of the embodiment of the present invention.

[0044] Figure 9B Vertical 3D directivity diagram of the waveguide of the embodiment of the present invention.

[0045] Figure 10 is the same test conditions for the same embodiment of the present invention and prior art sound pressure level comparison curve.

[0046] Figure 11A and 11B is the same frequency range of the present invention using two identical drivers working in the frequency response curve.

[0047] Figure 12A and 12B is the different frequency range of the present invention using two different drivers working in the frequency response curve.

[0048] Figure 13A is the vertical array combination of the loudspeaker according to the application of the waveguide application design schematic diagram.

[0049] Figure 13B and Figure 13C is the coupling diagram of the waveguide in the vertical array combination of the loudspeaker according to the application. DETAILED DESCRIPTION

[0050] The present application will be further described below in conjunction with the accompanying drawings of the specification.

[0051] As Figure 1 , the schematic diagram of point sound source and spherical wave, as shown, the wave front generated by point sound source 2 is concentric spherical wave, which is called spherical wave. Imagine that there is a spherical sound source in an infinite homogeneous medium, the surface of which 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 spherical wave. This sound wave is spherically symmetric, that is, the sound pressure is only related to the distance from the center of the sphere. Any shape of sound source, as long as its size is much smaller than the wavelength, can be regarded as a point sound source, which radiates spherical wave. For spherical wave, 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 sound source distance increases from R to R2, which is twice R, the wave front area increases from A to 4A, and the sound intensity decreases to 1 / 4.

[0052] As Figure 2 , the schematic diagram of line sound source and cylindrical wave, as shown, the wave front generated by line sound source 4 is coaxial cylindrical wave, which is called cylindrical wave. Cylindrical wave is a wave whose wave front is a coaxial cylinder. Imagine that there is an infinite long uniform line sound source in an infinite homogeneous medium, and the wave generated by it is an ideal cylindrical sound wave. In cylindrical sound wave, the sound pressure amplitude distribution along the axial direction is uniform, and 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 distance from the axis. As shown in the figure, when the sound source distance increases from R to R2, which is twice R, the wave front area increases from A to 2A, and the sound intensity decreases to 1 / 2.

[0053] As Figure 3AAs shown, when two ribbon tweeters 6 are horizontally arranged, because of the volume limitation of ribbon tweeters, the sound source spacing M is 109mm, and the corresponding coupling upper limit frequency Fh=3155Hz. Figure 3A The interference of two ribbon tweeters is shown, and the straight line indicates that the frequency less than 3155Hz is propagated in the form of plane wave, and the comb filter interference starts to appear when the frequency is greater than 3155Hz.

[0054] As shown, Figure 3B As shown, when two compression tweeters 8 are horizontally arranged via the waveguide 10 as in the US005163167A patent, the sound source center distance M is 18mm, and the corresponding coupling upper limit frequency Fh=9555Hz, Figure 3B The interference of two waveguides is shown, and the straight line indicates that the frequency less than 9555Hz is propagated in the form of plane wave, and the interference starts to appear when the frequency is greater than 9555Hz.

[0055] As shown, Figure 3C Figure 3C is a schematic diagram of the horizontal coupling of the waveguide and the tweeter of the present application. The tweeter waveguide 12 designed according to the present application is Y-shaped, including two waveguide channels arranged horizontally, one waveguide channel is connected with a spherical wave tweeter 14A, and the other waveguide channel is connected with a cylindrical wave tweeter 14B. The rectangular opening width W of the tweeter waveguide 12 is 18mm, and according to W≤λ, the working upper limit frequency is calculated to be 19KHz. Figure 3C The waveguide designed and implemented according to the present application is shown to propagate in the form of plane wave without sound wave interference when the frequency is less than 19kHz.

[0056] As shown, Figure 4 Figure 4 ​​This is a cross-sectional view of the tweeter horn of the present invention on a horizontal plane passing through the center of the waveguide. The present invention provides a tweeter horn 16 comprising a dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide 18, and two tweeter drivers 14A and 14B installed at the entrance end of the tweeter waveguide channel. Waveguide 18 is Y-shaped and includes two horizontally arranged waveguide channels 20A and 20B. The first waveguide channel 20A is used to connect to the spherical wave tweeter driver 14A. The first waveguide channel 20A is composed of a first channel 22A, a first reflecting surface 24A, a second channel 26A, a second reflecting surface 28A, and a third channel 30A connected in sequence. The first channel 22A is parabolic, the first reflecting surface 24A is elliptical, the second channel 26A is hyperboloid, the second reflecting surface 28A is rectangular, and the third channel 30A is rectangular. The second waveguide channel 20B is used to connect to the plane wave sound source 14B. The second waveguide channel 20B is composed of a fourth channel 22B, a third reflecting surface 24B, a fifth channel 26B, a fourth reflecting surface 28B, and a sixth channel 30B connected in sequence. The fourth channel 22B, the third reflecting surface 24B, the fifth channel 26B, the fourth reflecting surface 28B, and the sixth channel 30B are all right-angled rectangular surfaces.

[0057] like Figure 4 As shown, the first channel 22A is composed of a pair of mutually fitted convex parabolic surfaces 34A and concave parabolic surfaces 32A, and the first channel 22A is formed by the space between the two parabolic surfaces 34A and 32A.

[0058] like Figure 5A As shown, Figure 5A This is a schematic diagram of the inner wall of the first waveguide channel of the present invention. The parabolic section 33A of the concave parabolic surface 32A is the parabolic section of the elliptical surface of the first reflecting surface 24A. The parabolic section 35A of the elliptical surface of the first reflecting surface 24A is the parabolic section of the hyperboloid 36A of the second channel. The inner wall 40A of the third channel is connected to the inner wall 36A of the second channel. Because the inner wall 40A of the third channel is zigzag, there are connections between the inner walls 40A of the third channel.

[0059] like Figure 5B As shown, Figure 5B This is a schematic diagram of the outer wall of the first waveguide channel of the present invention. The convex parabolic surface 34A is a portion of a right-angled cone, with its vertex angle F being less than or equal to 90°. The parabola 37A of its end parabolic surface 34A is the parabola of the second hyperboloid 38A section of the second channel 26A. The convex parabolic surface 34A, the outer wall of the second channel 38A, the second reflecting surface 28A, and the outer wall of the third channel 42A are connected sequentially.

[0060] like Figure 4As shown, the second channel 26A is connected to the first channel 22A through the first reflective surface 24A, and the second channel 26A is connected to the third channel 30A through the second reflective surface 28A. The second channel 26A is located between the first reflective surface 24A and the second reflective surface 28A. The first reflective surface 24A is located at the end of the first channel 22A and is an elliptical reflective surface. The second reflective surface 28A is a rectangular plane. In the horizontal cross-sectional view, the second channel 26A is composed of a parallel inner wall 36A and an outer wall 38A. The inlet end of the inner wall 36A of the second channel 26A is connected to the first reflective surface 24A, the inlet end of the outer wall 38A of the second channel 26A is connected to the convex parabolic surface 34A, and the outlet end of the outer wall 38A of the second channel 26A is connected to the second reflective surface 28A.

[0061] like Figure 5C As shown, Figure 5C This is a schematic diagram of the propagation path of the acoustic ray in the first waveguide channel. The acoustic ray passes through the first channel 22A. The incident endpoint, reflection point, and the starting point of the reflected ray are coplanar. The acoustic ray reflected by the first reflecting surface 24A to the second channel 26A obeys the law of reflection, i.e., the angle of incidence equals the angle of reflection: θi₁ = θr₁ = θi₂ = θr₂. The path difference δ between the acoustic ray and the first waveguide channel 20A is: δ ≤ λ / 4.

[0062] like Figure 4 As shown in the horizontal cross-sectional view, the third channel 30A is composed of an inner wall 40A and an outer wall 42A. The inlet end of the outer wall 42A is connected to the second reflecting surface 28A, and the inlet end of the inner wall 40A is connected to the inner wall 36A of the second channel. The centerline of the first channel 22A is parallel to the outer wall 42A of the third channel 30A. The inner wall 40A of the third channel 30A is zigzag-shaped, with its inlet section parallel to the outer wall 42A. One end of the outlet section of the inner wall 40A is connected to the inlet section, and the other end is connected to the outlet 44. As an alternative, the inner wall 40A of the third channel 30A can be straight, with one end connected to the inner wall 36A of the second channel and the other end connected to the outlet 44.

[0063] like Figure 4As shown in the horizontal cross-sectional view, the fourth channel 22B is composed of the inner wall 32B and the outer wall 34B of the fourth channel; the fifth channel 26B is composed of the inner wall 36B and the outer wall 38B of the fifth channel; and the sixth channel 30B is composed of the inner wall 40B and the outer wall 42B of the sixth channel. The inner wall 32B of the fourth channel, the third reflecting surface 24B, the inner wall 36B of the fifth channel, and the inner wall 40B of the sixth channel are connected in sequence to form the inner wall of the second waveguide channel 20B. The outer wall 34B of the fourth channel, the outer wall 38B of the fifth channel, the fourth reflecting surface 28B, and the outer wall 42B of the sixth channel are connected in sequence to form the outer wall of the second waveguide channel 20B.

[0064] like Figure 4 As shown, in the horizontal cross-sectional view, the inner wall 32B of the fourth channel and the outer wall 34B of the fourth channel are parallel and of equal length; the inner wall 36B of the fifth channel and the outer wall 38B of the fifth channel are parallel and of equal length; the third reflecting surface 24B and the fourth reflecting surface 28B are parallel and of equal length; the outer wall 42B of the sixth channel is parallel to the inner wall 32B of the fourth channel; the inner wall 40B of the sixth channel is zigzag-shaped; the inlet section of the inner wall 40B of the sixth channel is parallel to the outer wall 42B of the sixth channel; one end of the outlet section of the inner wall 40B of the sixth channel is connected to the inlet section of the inner wall 40B of the sixth channel, and the other end is connected to the outlet 44 of the sixth channel. As an alternative, the inner wall 40B of the sixth channel can be straight, with one end connected to the inner wall 36B of the fifth channel and the other end connected to the outlet 44 of the sixth channel.

[0065] like Figure 5D As shown, Figure 5D This is a schematic diagram of the propagation path of the acoustic ray in the second waveguide channel. The acoustic ray passes through the fourth channel 22B, the third reflecting surface 24B, the fifth channel 26B, the fourth reflecting surface 28B, and the sixth channel 30B. The acoustic ray passing through the third reflecting surface 24B and the fourth reflecting surface 28B obeys the law of reflection, that is, the angle of incidence equals the angle of reflection: θi 3 = θr3 = θi 4 = θr4. The path difference δ between the acoustic ray and the second waveguide channel 20D is: δ ≤ λ / 4.

[0066] like Figure 4As shown, the waveguide 18 includes 3 pieces of shell, convex parabolic surface 34A, second channel outer wall 38A, second reflecting surface 28A, and third channel outer wall 42 connected in sequence, constituting the outer shell of the first waveguide channel 20A. Concave parabolic surface 32A, first reflecting surface 24A, second channel inner wall 36A, and third channel inner wall 40 connected in sequence, constituting the inner shell of the first waveguide channel 20A. Fourth channel inner wall 32B, third reflecting surface 24B, fifth channel inner wall 36B, and sixth channel inner wall 40B connected in sequence, constituting the inner shell of the second waveguide channel 20B. The inner shell of the first waveguide channel 20A and the inner shell of the second waveguide channel 20B are connected to each other at the first reflecting surface 24A and the third reflecting surface 24B, at the entrance of the second channel inner wall 36A and the fifth channel inner wall 36B, and at the common outlet 44 of the third channel 30A and the sixth channel 30B, together constituting the inner shell of the waveguide 18. Fourth channel outer wall 34B, fifth channel outer wall 38B, fourth reflecting surface 28B, and sixth channel outer wall 42B connected in sequence, constituting the outer shell of the second waveguide channel 20B. The internal structure of the first waveguide channel 20A has a rectangular surface, a parabolic surface, or a related curved surface shape feature. There are flanges at the entrance ends of the first channel 22A and the fourth channel 22B, which can be connected to the spherical wave tweeter driver 14A and the cylindrical wave tweeter driver 14B respectively by using screws through the through holes on the flanges.

[0067] As an improvement, an equal division grid (not shown in the figure) can be added in the first waveguide channel 20A and the second waveguide channel 20B, which can improve the strength of the parts, at the same time can suppress the resonance caused by the physical properties of the material under large sound pressure, and can reduce unnecessary diffraction of sound waves in the sound wave channel, improve the effective upper limit of high frequency, and reduce distortion.

[0068] The present invention relates to a sound wave coupling waveguide. Based on the principle of geometric acoustics, that is, the acoustic field based on the ray theory. Therefore, the present invention uses the characteristics of the propagation of sound that are known in optics, such as the law of reflection, Fermat's principle of least time, etc. The parabolic parabolic surface, hyperboloid, elliptical surface, etc. used in the present invention can be obtained by cutting the conical cross-sectional surface (referring to the surface generated by rotating the curve from the conical surface). More specifically, in the context of the present invention, surfaces with the following geometric characteristics are used: rectangular surface, hyperboloid, parabolic surface or ellipsoid, etc. to reflect sound waves to complete the design. It includes a periscope type waveguide, which has multiple sound wave channel slots, the sound wave channel slots are in a periscope structure, and the inside is composed of various shape structures with obvious geometric characteristics, including multiple incident channels, reflecting surfaces, and reflecting channels.

[0069] As shown in Figure 4 As shown in Figure 4As shown, point A is the center point on the emitting surface of the spherical wave tweeter driver 14A, point B is the midpoint of the first reflecting surface 24A, point C is the midpoint of the second reflecting surface 28A, and point D is the midpoint of the waveguide outlet. Line segment AB represents the incident path of the sound wave, i.e., the first channel 22A; line segment BC represents the reflected path of the sound wave, i.e., the second channel 26A; and line segment CD represents the third channel 30A. Similarly, the relationship of the sound wave reflection paths within the second waveguide channel 20B is as follows... Figure 4 As shown, point A is the center point on the emitting surface of the plane wave sound source 14B, point B is the midpoint of the third reflecting surface 24B, point C is the midpoint of the fourth reflecting surface 28B, and point D is the midpoint of the waveguide outlet. Line segment AB represents the incident path of the sound wave, i.e., the fourth channel 22B, line segment BC represents the reflection path of the sound wave, i.e., the fifth channel 26B, and line segment CD represents the sixth channel 30B.

[0070] like Figure 4 As shown, the sound wave propagates in the first waveguide channel 20A, following the following paths: (1) The sound wave is emitted from any point on the emitting surface of the spherical wave tweeter 14A, travels along path AB, and passes through the first channel 22A; (2) The sound wave is reflected by the first reflecting surface 24A, travels along path BC, and passes through the second channel 26A; (3) The sound wave is reflected by the second reflecting surface 28A, travels along path CD, and passes through the third channel 30A. The first reflecting surface 24A forms an arc with the horizontal plane passing through the center of the waveguide, and the tangent at the midpoint of the arc is parallel to the second reflecting surface 28A, indicating that the first reflecting surface 24A and the second reflecting surface 28A are parallel. Accordingly, based on the fundamental principle of the law of reflection, (1) the connection between the first reflecting surface 24A and the horizontal plane passing through the center of the waveguide forms an arc, and the normal BN at the midpoint of the arc is parallel to the normal CN of the second reflecting surface 28A; (2) the angle of incidence of the sound wave along path AB to the first reflecting surface 24A is equal to the angle of reflection of the sound wave along path BC; (3) the angle of incidence of the sound wave along path BC to the second reflecting surface 28A is equal to the angle of reflection of the sound wave along path CD. Therefore, the sound wave propagates along paths AB, BC, and CD, and after being reflected twice by the first reflecting surface 24A and the second reflecting surface 28A, it constitutes a periscope-type reflection system.

[0071] Correspondingly, the sound wave entering path AB from the emitting surface by the spherical wave tweeter driver 14A is a parallel ray. After being reflected by the first reflecting surface 24A, the sound wave propagates along path BC, also remaining a parallel ray. After being reflected again by the second reflecting surface 28A, it still remains a parallel ray. Parallel sound wave rays essentially eliminate diffraction that is detrimental to sound transmission coupling. This is a significant advantage of this invention compared to other waveguide structures. Furthermore, in the sound wave paths AB, BC, and CD, the incident ray AB, the reflected ray BC, the reflected ray CD, and the normal all lie on the same plane, which is also one of the conditions of the law of reflection.

[0072] Similarly, such asFigure 4 As shown, the sound wave propagates in the second waveguide channel 20B, and there are the following paths: (1) The sound wave is emitted from any point on the emitting surface of the plane wave source 14B, along path AB, and passes through the fourth channel 22B; (2) The sound wave is reflected by the third reflecting surface 24B, along path BC, and passes through the fifth channel 26B; (3) The sound wave is reflected by the fourth reflecting surface 28B, along path CD, and passes through the sixth channel 30B. Among them, the third reflecting surface 24B is parallel to the fourth reflecting surface 28B. Accordingly, according to the basic principle of the law of reflection, (1) the normal BN of the third reflecting surface 24B is parallel to the normal CN of the fourth reflecting surface 28B; (2) the incident angle of the sound wave along path AB to the third reflecting surface 24B is equal to the reflection angle of the sound wave along path BC; (3) the incident angle of the sound wave along path BC to the fourth reflecting surface 28B is equal to the reflection angle of the sound wave along path CD. Therefore, the sound wave propagates along paths AB, BC, and CD, and is reflected twice by the third reflecting surface 24B and the fourth reflecting surface 28B, thus forming a periscope-style reflection system.

[0073] Correspondingly, the sound wave entering the plane wave source 14B from the emitting surface along path AB is a parallel ray. After being reflected by the third reflecting surface 24B, the sound wave propagates along path BC, also remaining a parallel ray. After being reflected again by the fourth reflecting surface 28B, it still remains a parallel ray. Parallel sound wave rays essentially eliminate diffraction, which is detrimental to sound transmission coupling. This is a significant advantage of this invention compared to other waveguide structures. Furthermore, in the sound wave paths AB, BC, and CD, the incident ray AB, the reflected ray BC, the reflected ray CD, and the normal all lie on the same plane, which is also one of the conditions of the law of reflection.

[0074] According to Fermat's shortest time principle, the path taken by light (or, in the case of this waveguide structure, sound waves) from one point to another will be the path that minimizes the propagation time. In situations such as... Figure 4 Under the conditions shown, the sound wave will choose the path that minimizes the total propagation time from A to D. Assuming the speed of the sound wave in the medium is v, the time t from A to B, then to C, and finally to D is: t = AB / v + BC / v + CD / v = (AB + BC + CD) / v. This time will be minimized when the angle of incidence equals the angle of reflection for AB and BC, CD. This is because, given a fixed length of AB + BC + CD, the path from AB to BC, CD is shortest when the angle of incidence equals the angle of reflection, resulting in minimal sound wave propagation attenuation.

[0075] Based on the above, it can be deduced that in this invention, the sound rays from the emitting surface A to the wavefront D point all travel along the shortest straight path. In this invention, the time T from the emitting surface A to the wavefront D point is equal. When the time T is equal, the sound waves in the sound wave paths AB, BC, and CD are all in phase, that is, they are all equal-phase and equidistant cylindrical waves of a linear sound source.

[0076] In this implementation, it is understood that the acoustic waveguide channel guides the sound source ray and corrects the sound wave path. This is not limited to the aforementioned conical (curved) or rectangular structures; other (reflective) surfaces can also be used. It is understood that the waveguide channel's reflective surface can be multi-channel, manifold, flat, annular parabolic, hyperbolic, or elliptical; or more generally, flat, concave, or convex, for example, annular, parabolic, or multi-channel, manifold, and other structural methods.

[0077] The accuracy of the upper limit of usable frequency for a waveguide is often used as a measure of a successful design, especially for ultra-high frequencies with very short wavelengths. The waveguide acoustic channel slot design, within the necessary effective frequency range and the wavelength of the associated operating frequency, limits the width of the associated acoustic channel and the overall height of the waveguide.

[0078] like Figure 4 As shown, in the first waveguide channel 20A, the following geometric path relationships exist in the acoustic wave paths AB, BC, and CD: (1) The lengths of the concave parabolic surface 32A and the convex parabolic surface 34A are equal; (2) The lengths of the first reflecting surface 24A and the second reflecting surface 28A are equal; (3) The lengths of the inner wall 36A of the second channel and the outer wall 38A of the second channel are equal; (4) The difference between the length of the inner wall 40A of the third channel and the length of the outer wall 42A of the third channel needs to be less than the distance from the end of the outer wall 42A of the third channel to the end 44 of the third channel.

[0079] Similarly, such as Figure 4 As shown, in the second waveguide channel 20B, the following geometric path relationships exist in the acoustic wave paths AB, BC, and CD: (1) The lengths of the inner wall 32B and the outer wall 34B of the fourth channel are equal; (2) The lengths of the third reflecting surface 24B and the fourth reflecting surface 28B are equal; (3) The lengths of the inner wall 36B and the outer wall 38B of the fifth channel are equal; (4) The difference between the length of the inner wall 40B of the sixth channel and the length of the outer wall 42B of the sixth channel needs to be less than the distance from the end of the outer wall 42B of the sixth channel to the end 44 of the sixth channel.

[0080] like Figure 5BAs shown, the convex parabolic surface 34A, the outer wall of the second channel 38A, the second reflecting surface 28A, and the outer wall of the third channel 4A2 are connected sequentially to form the outer shell of the first waveguide channel. The overall height of the outer shell is H. The acoustic wave paths AB, BC, and CD have the following geometric path relationship: L = Ln, where L = AB + BC + CD, which is the total path length of the cross-section from point A on the sound source emitting surface of the waveguide to point D at the waveguide outlet; and Ln = ABn + BCn + CDn, where n is the total path length from any point A on the sound source emitting surface of the waveguide to any point D at height H above the waveguide outlet. The path difference δ between the acoustic waves passing through the first waveguide channel is the difference between any two Ln values. When L = Ln, all paths are of equal length, and the path difference δ is zero.

[0081] like Figure 4 As shown, when the emitting surface diameter of the spherical wave tweeter 14A is greater than the spatial width of the first channel 22A, the concave parabolic surface 32A needs to adjust the right-angled cone and the generatrix of the convex parabolic surface 34A to be an arc during the fitting process of the convex parabolic surface 34A. The distance between the two parabolic surfaces gradually transitions from the emitting surface diameter of the spherical wave tweeter 14A to the spatial width required at the outlet end of the first channel 22A.

[0082] like Figure 4 As shown, based on the operating parameters of the selected tweeters 14A and 14B, the following design can be made according to the acoustic relationship. (1) Based on the wavelength λ of the highest usable frequency of the waveguide design target, the total width W of the rectangular plane output port at the waveguide outlet end can be calculated, where W1 + W2 = λ = W, and W1 and W2 are the widths of the left and right outlets of the waveguide, respectively. For example, if the highest usable frequency of the waveguide design target is 20KHz, and the sound propagation speed is taken as 343.2m / s, then the corresponding wavelength λ of the highest usable frequency is equal to 17.16 mm. Accordingly, the total width W of the rectangular plane output port at the waveguide outlet end is equal to 17.16 mm. If the highest usable frequencies of the tweeters corresponding to the two waveguide channels are the same, then W1 = W2 = 8.58 mm. (2) Based on the wavelengths λ3 and λ4 of the highest usable frequency of the waveguide design target on the left and right sides, the width W3 of the left reflection channel 26 and the width W4 of the right reflection channel 26 of the waveguide can be calculated, where W3 = λ3 and W4 = λ4. For example, if the highest usable frequency wavelengths λ3 and λ4 on both sides of the waveguide are equal and both 20 kHz, and the speed of sound is taken as 343.2 m / s, then the corresponding highest usable frequency wavelengths λ3 and λ4 are equal to 17.16 mm. Accordingly, W3 = W4 = 17.16 mm. If, according to specific acoustic application requirements, the highest usable frequency wavelengths λ3 and λ4 on the left and right sides of the waveguide are not equal, then W3 and W4 need to be calculated separately.

[0083] likeFigure 5B As shown, based on the minimum usable frequency wavelength λ5 of the waveguide design target, the total height H of the rectangular planar output port at the waveguide outlet end can be calculated, where H ≥ λ5 / 2. For example, if the minimum usable frequency of the waveguide design target is 800Hz, and the speed of sound is taken as 343.2m / s, then the corresponding minimum usable frequency wavelength λ is equal to 429 mm. Accordingly, according to H ≥ λ5 / 2, the total height H of the rectangular planar output port at the waveguide outlet end is equal to 214.5 mm.

[0084] like Figure 4 The widths W1 and W2 shown are obtained by correcting the widths of the third channel 30A and the sixth channel 30B, respectively. Where W1 = W3 / 2, W2 = W4 / 2. On the horizontal plane passing through the waveguide center, the centerline AB of the first channel is parallel to the outer wall 42A of the third channel. The inner wall 40A of the third channel 30A is a broken line. The entrance section of the inner wall 40A of the third channel 30A is parallel to the outer wall 42A of the third channel 30A. One end of the exit section of the inner wall 40A of the third channel 30A is connected to the entrance section of the inner wall 40A of the third channel 30A, and the other end is connected to the exit 44 of the third channel 30A. As an alternative, the inner wall 40A of the third channel 30A can be a straight line, with one end connected to the inner wall 36A of the second channel and the other end connected to the exit 44 of the third channel 30A. Similarly, the outer wall 42B of the sixth channel is parallel to the inner wall 32B of the fourth channel, the inner wall 40B of the sixth channel is zigzag-shaped, the inlet section of the inner wall 40B of the sixth channel is parallel to the outer wall 42B of the sixth channel, and one end of the outlet section of the inner wall 40B of the sixth channel is connected to the inlet section of the inner wall 40B of the sixth channel, and the other end is connected to the outlet 44 of the sixth channel 30B. As an alternative, the inner wall 40B of the sixth channel 30B can be straight, with one end connected to the inner wall 36B of the fifth channel and the other end connected to the outlet 44 of the sixth channel 30B.

[0085] like Figure 4 As shown, in cylindrical mode propagation, the axis of the cylinder is vertical, making the output rectangle an equiphase plane, which requires the following conditions to be met: (1) When the two tweeters 14A or 14B are operating in the same frequency band, W3=W4≤W1+W2≤W. (2) When the two sound sources are operating in different frequency bands, W1+W2=W.

[0086] like Figure 5B As shown, δ is the maximum length deviation between acoustic paths of the waveguide design target available frequency, that is, the path difference on L from any point A to any point D on the sound wave emitting surface. For effective coupling, δ needs to be less than a quarter wavelength of the highest design target available effective frequency, i.e.: δ≤λ / 4.

[0087] like Figure 5B As shown, in order for the propagation to be effectively cylindrical along the vertical axis, it is necessary for H to be greater than λ5.

[0088] As shown in Figure 4 α1 < α2 < α3, where α1 is the angle between the first reflecting surface 24A and the third reflecting surface 24B. α2 is the angle between the second channel inner wall 36A and the fifth channel inner wall 36B. α3 is the angle between the third channel inner wall 40A and the sixth channel inner wall 40B at the end 44.

[0089] According to one embodiment of the present application, the highest available frequency wavelength λ = 18 kHz, and the corresponding W = 18 mm. Two identical sound sources 20 are selected, W1 = 9 mm, W2 = 9 mm, W3 = 18 mm, and W4 = 18 mm.

[0090] As shown in Figure 4 The diameter of the emitting surface of the spherical wave tweeter 14A is 35 mm. Therefore, in the process of fitting the convex parabolic surface 34A, the distance between the two parabolic surfaces gradually decreases from the diameter of the emitting surface of the spherical wave tweeter 14A, which is 35 mm, to 18 mm at the outlet end of the first waveguide channel 20A, so as to facilitate the propagation of sound waves in the form of cylindrical waves in the channel of the first waveguide channel 20A.

[0091] As shown in Figure 4 The tangent line of the first reflecting surface 24A and the horizontal plane passing through the center of the waveguide and the connecting point B is parallel to the second reflecting surface 28A. Therefore, the incidence angle and the reflection angle of the two reflections can be selected as 45°, forming a periscopic reflection system.

[0092] As shown in Figure 5B The horizontal center section physical path length L = 210 mm from the sound source emitting surface A to the wave front output D'. The length Ln = 210 mm from the sound source emitting surface A to any point on the physical path of the wave front output Dn, which meets the need for equal distance propagation of sound waves.

[0093] As shown in Figure 5B The total height H = 210 mm of the rectangular plane output at the outlet end of the waveguide is selected as the design target lowest available frequency wavelength λ5, which corresponds to the design target lowest available frequency of about 800 Hz.

[0094] It should be understood that these dimensions are not restrictive, but are simply given by way of example to illustrate an example of implementing the present application.

[0095] As shown in Figure 6A As can be seen from the horizontal section view of the sound box 45 designed according to the present application, the horn 16 is centered in the box 46, and the waveguide 18 is shown in a periscopic structure with two waveguide channels on the left and right. Two bass units 48 are horizontally symmetrically arranged and installed on the panel 50.

[0096] AsFigure 6B As shown, by viewing the front of the cabinet 46, one can see the hollow periscopic structure sound wave channel between the third channel inner wall end 44 and the third channel outer wall, the hollow periscopic structure sound wave channel between the sixth channel inner wall end 44 and the sixth channel outer wall, and the sound wave output slot 54 formed by the rectangular cutout 52 of the faceplate 50, that is, the wavefront exit.

[0097] The technical advantages of the present application can be demonstrated by comparison with the prior art.

[0098] US20110085692A1 discloses a dual diaphragm driver, as shown in the drawings of the patent, the wavefront is formed by two annular plane diaphragms, two identical diameter size diaphragms work in the same frequency band at the same time, and the output is coupled through a common cavity.

[0099] US20130243232A1 discloses a dual diaphragm driver with waveguide output, in which two diaphragms can be of the same diameter size or different diameter size, and the diaphragm sound waves are coupled through a common cavity wavefront for output.

[0100] The final result of the implementation of the above two schemes into products is: (1) two diaphragms work in the same frequency band, the maximum sound pressure level increases by 6dB (the calculation formula is L_max = L + 20 * log20(n), L represents the sound pressure level of a single speaker, and n represents the number of drivers), and the general effective usable frequency band is 800Hz-20KHz; (2) two diaphragms work in different frequency bands (the extended working frequency band can reach 300Hz-20KHz), the effective usable frequency band of the small size diaphragm is 3KHz-20KHz, and the effective usable frequency band of the large size diaphragm is at least 300Hz-6KHz.

[0101] The advantages of the above two inventions are relatively small structure. Since sound waves are mechanical waves that propagate through the mechanical vibration of molecules and particles in a medium. They propagate in the form of longitudinal waves, transferring energy through the interaction between molecules. When sound waves propagate in air, they cause changes in air pressure. When the sound source vibrates, it produces continuous compression and rarefaction vibrations, forming sound waves. These vibrations cause the movement of air molecules, causing changes in pressure in the air. During the propagation of sound waves in air, the vibration of the sound source causes the compression and rarefaction of the surrounding air molecules. When the sound source vibrates outward, it pushes the air molecules together, forming a compression region and increasing the pressure. When the sound source vibrates inward, it pulls the air molecules apart, forming a rarefaction region and reducing the pressure. This periodic change in pressure is transmitted along the direction of sound wave propagation.

[0102] From the above two patent structures, the diaphragm is a common cavity and works at the same time, and the wave front coupling is completed in the cavity. When the driver works at high power, the pressure in the cavity will change, causing the change of acoustic resistance, thereby causing nonlinear distortion, which is particularly obvious at high power. The diaphragm has good high-frequency response transient if the diaphragm material is not rigid enough, and the diaphragm is prone to nonlinear distortion at high power. The diaphragm has good mid-frequency response, but the high-frequency efficiency is low, and the high-frequency 8KHz-20KHz part is severely attenuated, reaching about 10dB. When the diaphragm works individually, the pressure in the cavity is P, and when the two diaphragms work, the pressure increases by 2P. In this case, only the diaphragm is thickened to solve the distortion problem caused by the 2P pressure in the cavity. The problem of thickening the diaphragm is low high-frequency efficiency.

[0103] As Figure 7 shown, the figure is a comparison chart of test curves of the mass production driver in US20110085692A1 patent and the waveguide of the present application under the same test conditions. As can be seen from the comparison of the curve of the mass production driver in US20110085692A1 patent (labeled A at the curve turning position) and the curve of the waveguide of the present application (labeled B at the curve turning position), the efficiency of US20110085692A1 patent is relatively high in the frequency band of 500Hz-5KHz, while the attenuation in the high frequency band of 4KHz-20KHz (identified by F frame) is severe, reaching about 10dB. This is not conducive to the application in linear array sound amplification, and the air attenuation in long-distance sound amplification is mainly in the high frequency band of 4KHz-20KHz.

[0104] Similarly, the data table of one implementation of patent US20130243232A1 published compressed drive waveguide shows that the high-frequency diaphragm size is 1.75" (44.4 mm), the mid-high-frequency diaphragm size is 3.5" (90 mm), and the working frequency range is 400Hz-22000Hz. When the two diaphragms work together, the high-frequency diaphragm size of 1.75" is at the same pressure as the mid-high-frequency diaphragm size of 3.5" (90 mm), but the thickness of the diaphragm is different, thereby causing high-frequency distortion. The greater the power, the greater the nonlinear distortion.

[0105] The present application achieves the same purpose as the above two patents by the following two methods:

[0106] (1) Two sound sources work in the same frequency band to expand the sound pressure level method, the maximum sound pressure level increases by 6dB (the calculation formula is L_max = L + 20 * log20(n) L represents the sound pressure level of a single sound source, and n represents the number of sound source drivers). The general working effective frequency band is 800Hz-20KHz.

[0107] (2) Two sound sources work in different frequency band extension frequency width method (expanding the working frequency band can reach 300Hz-20KHz), the effective frequency band of small size diaphragm is 3KHz-20KHz, and the effective frequency band of large size diaphragm is 300Hz-6KHz). The distortion problem caused by the physical defects of the above hardware is solved by the method of wave front coupling of two tweeter drivers not sharing the cavity, and the following application design advantages are also provided:

[0108] (1) The method implemented by the present application is compatible with any tweeter driver currently produced in the industry, including traditional tweeter compression drivers and ribbon tweeter drivers. The above two patents or similar patents cannot be realized due to physical structure or technical characteristics;

[0109] (2) The implementation of the above two patents is the product of their own technology, and has its own inherent technical characteristics or sound style. In the implementation method of the present application, two tweeter drivers can be selected from different manufacturers' mass-produced driver designs to obtain different sound styles and products. Through the design of the waveguide, the sound box is matched with different tweeter drivers to obtain different sound styles and products;

[0110] (3) According to the scheme of the present application, two different sound sources work in different frequency bands, which can expand the frequency response. Due to the wave front not sharing the cavity structure, the two sound sources have a wider frequency width in the overlapping area, which is beneficial to the flexible frequency division design of the research and development engineers. In the prior art, the frequency response curve in the overlapping area has many peaks and valleys, and the selection of the frequency division point is very narrow, which is not conducive to the flexible design and application of the research and development personnel.

[0111] The waveguide of the present application is completed by a mold using the following materials, such as metal, ABS plastic, carbon fiber, resin, etc. Figure 4As shown, the waveguide 18 includes three pieces of housing, the convex parabolic surface 34A, the second passage outer wall 38A, the second reflecting surface 28A, and the third passage outer wall 42 connected in sequence to form the outer housing of the first waveguide passage 20A. The concave parabolic surface 32A, the first reflecting surface 24A, the second passage inner wall 36A, and the third passage inner wall 40 connected in sequence to form the inner housing of the first waveguide passage 20A. The fourth passage inner wall 32B, the third reflecting surface 24B, the fifth passage inner wall 36B, and the sixth passage inner wall 40B connected in sequence to form the inner housing of the second waveguide passage 20B. The inner housing of the first waveguide passage 20A and the inner housing of the second waveguide passage 20B are connected to each other at the first reflecting surface 24A and the third reflecting surface 24B, at the entrance of the second passage inner wall 36A and the fifth passage inner wall 36B, and at the common outlet 44 of the third passage 30A and the sixth passage 30B, to jointly form the inner housing of the waveguide 18. The fourth passage outer wall 34B, the fifth passage outer wall 38B, the fourth reflecting surface 28B, and the sixth passage outer wall 42B connected in sequence to form the outer housing of the second waveguide passage 20B. The space between the outer housing and the inner housing forms the sound wave passage of the waveguide 18, and in addition, the outer housing can further include flanges for fixing the tweeter drivers 14A and 14B. These components can be assembled by gluing, heat welding or screwing, ultrasonic welding and other processes.

[0112] The waveguide of the present application has an internal geometry shape such that the shortest paths from the emitting surface of the tweeter drivers to the output rectangular plane wave are all or almost equal in length. In the waveguide design application, the time for the sound wave to propagate through the periscopic reflecting passage slot is constant phase, and the shortest path is inside, without sound wave diffraction and other phenomena that are not conducive to sound wave transmission.

[0113] Due to the precision problem of mold production error, from the sound source emitting surface A point to D point plane wave front, the path difference δ between the allowed sound wave paths between them is: δ≤λ / 4, (λ is the wavelength of the highest available frequency of the design target), that is, the path difference is less than or equal to one-quarter of the highest operating frequency.

[0114] Therefore, the waveguide of the present application can convert the equal-phase spherical wave or cylindrical wave generated by two identical or different drivers into a cylindrical equal-phase wave coupled in the horizontal position, and the two cylindrical sound waves are coupled in the horizontal position to propagate in the form of a cylindrical wave.

[0115] Figure 8A Figure 8B Figure 9A Figure 9B The 3D directivity graph of the waveguide of the present application is tested under the same conditions as the prior art waveguide, wherein, Figure 8A is the horizontal 3D directivity graph of the prior art waveguide, Figure 8B is the vertical 3D directivity graph of the prior art waveguide. Figure 9A ​​​is the waveguide horizontal 3D directivity diagram of the embodiment of the present application, Figure 9B is the waveguide vertical 3D directivity diagram of the embodiment of the present application. Figure 8A and Figure 9A It can be found from the comparison of and that the waveguide of the present application is basically consistent with the waveguide of the prior art in the horizontal 3D directivity diagram, and the directivity is more uniform at about 16KHZ, and the design target frequency is reached, and the precision is higher than that of the prior art. It can be found from the comparison of and that the waveguide of the present application is basically consistent with the waveguide of the prior art in the vertical 3D directivity diagram, and the directivity is narrower at a higher frequency, and there is no other sidelobe, which meets the directivity characteristics of a linear sound source. Figure 8B and Figure 9B It can be found from the comparison of and that the waveguide of the present application is basically consistent with the waveguide of the prior art in the horizontal 3D directivity diagram, and the directivity is more uniform at about 16KHZ, and the design target frequency is reached, and the precision is higher than that of the prior art. It can be found from the comparison of and that the waveguide of the present application is basically consistent with the waveguide of the prior art in the vertical 3D directivity diagram, and the directivity is narrower at a higher frequency, and there is no other sidelobe, which meets the directivity characteristics of a linear sound source.

[0116] As shown in Figure 10 , the sound pressure level curves in the figure are obtained by testing under the same conditions of using the same driving unit, the same 110° directivity control horn and the same voltage. It can be seen that the A sound pressure level curve (identified by the A frame) of the waveguide of the present application is about 6dB higher than the curve B (identified by the B frame) of the waveguide of the prior art as a whole, and the lower end usable frequency is as low as 800HZ, and the waveguide of the prior art is cut off at about 1KHZ. This technical advantage corresponds to another purpose of the present application, that is, to provide a method for increasing the sound pressure level output, in which multiple drivers working at the same frequency in the sound box are not coupled in the same cavity, and the maximum sound pressure level of the waveguide of the prior art is increased by ≥6dB.

[0117] As shown in Figure 11A and Figure 11B , Figure 11A and Figure 11B are frequency response curve diagrams of the present application using two same drivers working at the same frequency band: as shown in the figure, the B curve (identified by the B frame) is the frequency response curve when a single driver works, the A curve (identified by the A frame) is the coupling curve when the left and right two drivers work at the same time, and the C curve (identified by the C frame) is the phase curve. The calculation formula of the sound pressure level (SPL) is: L_max = L + 20 * log20(n), N represents the number of sound source drivers. When the two drivers work at the same time, the curve is perfectly superimposed by 6dB as a whole, and the phase curve C is completely consistent. As shown in the test results in the figure, the wave front coupling of the two tweeter drivers is free of any acoustic interference. This technical advantage corresponds to another purpose of the present application, that is, to provide a waveguide, which allows multiple tweeter drivers working at the same frequency range to generate common wave front coupling at the same horizontal position without being in the same cavity, and almost zero acoustic interference.

[0118] As shown in Figure 12A and Figure 12B , Figure 12A and Figure 12Bis the frequency response curve of the application using two different tweeter drivers working in different frequency bands. As shown in the figure, the high frequency driver A (identified by the curve with the A box) and the mid frequency compression driver B (identified by the curve with the B box) have a phase C (identified by the curve with the C box) that is basically consistent. The high frequency driver A can be used in the frequency band of 1KHz-18KHz, and the mid frequency compression driver B can be used in the frequency band of 300Hz-9KHz. As shown by the overlapping area F (identified by the F box) in the figure, the two drivers have a wide range of frequency division points, which makes the frequency division more flexible for designers. This technical advantage corresponds to another purpose of the application, that is, to provide a waveguide that allows multiple driver sound sources working in different frequency ranges to produce common coupling at the same wave front in the horizontal position without sharing the cavity and with almost zero acoustic interference.

[0119] Figure 13A is a schematic diagram of the vertical array combination of the sound box according to the waveguide application design of the application, Figure 13B and Figure 13C is a coupling diagram of the waveguide of the application in the vertical array combination of the sound box. As shown in Figure 13A , 3 sound boxes 45 are vertically stacked to form a vertical array combination 56 of sound boxes. As shown in Figure 13B and Figure 13C , 3 sets of horns 16, including spherical wave tweeter 14A and first waveguide channel 20A, and cylindrical wave tweeter 14B and second waveguide channel 20B, are coupled without interference when the sound boxes are vertically stacked. Multiple waveguides of the application are vertically coupled in the linear array sound box. This technical advantage corresponds to another purpose of the application, that is, to provide a waveguide that produces one or more wave fronts in one or more frequency ranges in the sound box, which couples the sound waves of the same frequency range in the adjacent sound boxes of the linear array vertically stacked and without acoustic interference.

Claims

1. A dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide, characterized in that, The waveguide is Y-shaped and includes two horizontally arranged waveguide channels. The first waveguide channel is used to connect to a spherical wave tweeter driver. The first waveguide channel consists of a first channel, a first reflecting surface, a second channel, a second reflecting surface, and a third channel connected in sequence. The first channel is a parabolic surface, the first reflecting surface is an elliptical surface, the second channel is a hyperboloid surface, the second reflecting surface is a rectangular surface, and the third channel is a rectangular surface. The second waveguide channel is used to connect to a plane wave sound source. The second waveguide channel consists of a fourth channel, a third reflecting surface, a fifth channel, a fourth reflecting surface, and a sixth channel connected in sequence. The fourth channel, the third reflecting surface, the fifth channel, the fourth reflecting surface, and the sixth channel are all right-angled rectangular surfaces.

2. The dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide according to claim 1, characterized in that, The first channel is composed of a pair of mutually fitted convex parabolic surfaces and concave parabolic surfaces. The first channel is formed by the space between the two parabolic surfaces. The parabola of the concave parabolic surface at its end is a parabola of the elliptical section of the first reflecting surface. The parabola of the elliptical section at the end of the first reflecting surface is a parabola of the hyperboloid section of the second channel. The convex parabolic surface is divided into a right-angled cone with a vertex angle less than or equal to 90°. The parabola of its end is a parabola of the hyperboloid section of the second channel.

3. The dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide according to claim 1, characterized in that... The second channel is connected to the first channel through the first reflective surface, and the second channel is connected to the third channel through the second reflective surface. The second channel is located between the first reflective surface and the second reflective surface. The first reflective surface is located at the end of the first channel and is an elliptical reflective surface. The second reflective surface is a rectangular plane. In the horizontal cross-sectional view, the second channel is composed of parallel inner and outer walls. The inlet end of the inner wall of the second channel is connected to the first reflective surface, the inlet end of the outer wall of the second channel is connected to the convex parabolic surface, and the outlet end of the outer wall of the second channel is connected to the second reflective surface.

4. The dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide according to claim 1, characterized in that... The acoustic ray passes through the first channel, the first reflecting surface, the second channel, the second reflecting surface, and the third channel. The acoustic ray passing through the first and second reflecting surfaces conforms to the law of reflection, that is, the angle of incidence equals the angle of reflection. The path difference δ between the acoustic waves passing through the first waveguide channels is: δ≤λ / 4, where λ is the wavelength of the highest usable frequency of the design target.

5. A dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide according to claim 1, characterized in that... In the horizontal cross-sectional view, the third channel is composed of an inner wall and an outer wall. The entrance end of the outer wall of the third channel is connected to the second reflective surface, and the entrance end of the inner wall of the third channel is connected to the inner wall of the second channel. The centerline of the first channel is parallel to the outer wall of the third channel. The inner wall of the third channel is zigzag-shaped. The entrance section of the inner wall of the third channel is parallel to the outer wall of the third channel. One end of the exit section of the inner wall of the third channel is connected to the entrance section of the inner wall of the third channel, and the other end is connected to the exit of the third channel.

6. A dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide according to claim 1, characterized in that... In the horizontal cross-sectional view, the fourth channel is composed of the inner wall and the outer wall of the fourth channel, the fifth channel is composed of the inner wall and the outer wall of the fifth channel, and the sixth channel is composed of the inner wall and the outer wall of the sixth channel. The inner wall of the fourth channel, the third reflecting surface, the inner wall of the fifth channel, and the inner wall of the sixth channel are connected in sequence to form the inner wall of the second waveguide channel. The outer wall of the fourth channel, the outer wall of the fifth channel, the fourth reflecting surface, and the outer wall of the sixth channel are connected in sequence to form the outer wall of the second waveguide channel.

7. A dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide according to claim 1, characterized in that... In the horizontal cross-sectional view, the inner wall of the fourth channel is parallel to the outer wall of the fourth channel and has the same length. The inner wall of the fifth channel is parallel to the outer wall of the fifth channel and has the same length. The third reflecting surface is parallel to the fourth reflecting surface and has the same length. The outer wall of the sixth channel is parallel to the inner wall of the fourth channel. The inner wall of the sixth channel is zigzag-shaped. The entrance section of the inner wall of the sixth channel is parallel to the outer wall of the sixth channel. One end of the exit section of the inner wall of the sixth channel is connected to the entrance section of the inner wall of the sixth channel, and the other end is connected to the exit of the sixth channel.

8. A dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide according to claim 1, characterized in that... The acoustic ray passes through the fourth channel, the third reflection surface, the fifth channel, the fourth reflection surface, and the sixth channel. The acoustic ray passing through the third and fourth reflection surfaces conforms to the law of reflection, that is, the angle of incidence equals the angle of reflection. The path difference δ between the acoustic waves passing through the second waveguide channels is: δ≤λ / 4, where λ is the wavelength of the highest usable frequency of the design target.

9. A tweeter horn, comprising a dual-source wavefront non-co-cavity horizontally coupled tweeter waveguide according to claim 1, and two tweeter drivers installed at the inlet end of the waveguide channel.

10. A speaker enclosure comprising a tweeter horn as claimed in claim 9, two mid-bass drivers arranged horizontally symmetrically on both sides of the tweeter horn, and an enclosure.

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