A device for adjusting horizontal coverage angle of column wave for sound amplification

Abstract

This invention provides an adjustable horizontal coverage angle device for cylindrical waves used in sound reinforcement. The device is installed at the front outlet of the cylindrical wave converter and is assembled from an adjustable horn plate, a rotating shaft, and a positioning device. The adjustable horn plate is hyperboloid in shape, and the deflection angle of the adjustable horn plate is set by the rotating shaft and the positioning device. This avoids the distortion caused by the flat-shaped directional control plate in the prior art. While facilitating the adjustment of the horizontal coverage angle of the cylindrical wave used in sound reinforcement, it also improves the sound quality of the amplified sound.

Description

Technical Field

[0001] This invention relates to sound reinforcement devices, and more particularly to a cylindrical wave adjustable horizontal coverage angle device for sound reinforcement. This device can reduce horn distortion and improve sound reinforcement quality. Background Technology

[0002] In traditional sound reinforcement systems, the high-frequency directional coverage is typically controlled by a horn, and the sound source is a point source with spherical wave transmission characteristics. In recent years, with the application of line array systems, line sources with cylindrical wave characteristics are increasingly being used in modern sound reinforcement systems. Cylindrical waves differ from spherical waves; typically, their horizontal wavefront spreads in cylindrical form, while their vertical directional coverage angle remains relatively constant (around 10°) and is not controlled by the horn's directivity. Therefore, in practical sound reinforcement applications, if the directional coverage angle of the cylindrical wave high frequencies of a line source needs to be changed, there are usually two methods: (1) changing to a horn with a different coverage angle; (2) custom-making a speaker with a different coverage angle. This inevitably leads to operational complexity and waste of materials, equipment, and manpower.

[0003] Existing technology, Chinese utility model patent ZL201020112737.X, discloses a sound amplification device capable of arbitrarily changing the high-frequency directional coverage angle of a cylindrical wave from a line sound source. For example... Figure 1 As shown, the device includes a tweeter driver 9, a loudspeaker, and a cylindrical wave converter 8 between the tweeter driver 9 and the loudspeaker. The loudspeaker is installed at the front outlet of the cylindrical wave converter 8. The loudspeaker includes a fixed plate 7, a rotating shaft 6, a directional control plate 2, upper and lower positioning plates 1, and an angle control slide rail 3 on the upper and lower positioning plates 1. There are two directional control plates 2, which are sandwiched between the upper and lower positioning plates 1. The two directional control plates 2 can rotate around the rotating shaft 6 to change the angle between them, thereby adjusting the high-frequency directional coverage angle of the cylindrical wave of the line sound source.

[0004] However, because the directional control board is flat, distortion occurs at the front outlet of the cylindrical wave converter 8 due to the "eddy current effect" caused by the "abrupt change". Summary of the Invention

[0005] The technical problem to be solved by the present invention is to avoid the distortion caused by the aforementioned flat plate pointing control plate, and to provide a cylindrical wave adjustable horizontal coverage angle device for sound reinforcement to improve the sound quality of sound reinforcement.

[0006] This invention provides a cylindrical wave adjustable horizontal coverage angle device for sound reinforcement. The device is installed at the front outlet of the cylindrical wave converter and is assembled from an adjustable horn plate, a rotating shaft, and a positioning device. The adjustable horn plate is characterized by having a hyperboloid shape and a hyperbola in cross-sectional shape, which conforms to the standard equation of a hyperbola: x^2 / a^2-y^2 / b^2=1.

[0007] As an improvement, in the hyperbolic standard equation of the adjustable horn plate, the parameter a = B / 2, where B is the horn throat width adapted to the adjustable horizontal coverage angle cylindrical wave device for sound reinforcement.

[0008] As an improvement, the throat width B of the adapted horn satisfies the following equation: B≤C / 2fup, where C is the speed of sound 340 m / s and fup is the upper limit of the effective high-frequency operation of the adapted horn.

[0009] As an improvement, in the standard equation of the hyperbola, the parameter b = a*tan(90°-α / 2), where α is twice the angle between the asymptote of the hyperbola and the Y-axis when the adjustable horizontal coverage angle cylindrical wave device for sound reinforcement achieves the maximum horizontal coverage angle.

[0010] As an improvement, the length of the adjustable horn plate is H = S / B, where S is the cross-sectional area of ​​the horn mouth adapted to the adjustable horizontal coverage angle device for the cylindrical wave of the sound reinforcement.

[0011] As an improvement, the cross-sectional area of ​​the horn mouth is S = π × (C / 2πf₀)^2, where C is the speed of sound (340 m / s) and f₀ is the horn's cutoff rate. Typically, the lower limit of the horn's effective operating frequency, f₀, is set to f₀ ≥ 2f₀, and f₀ is determined by the system's frequency division point, which is a known parameter.

[0012] As an improvement, the axis of rotation is located at the vertex of the hyperbola.

[0013] As an improvement, the positioning device consists of two positioning plates and a positioner set on both ends of the adjustable horn plate.

[0014] As an improvement, the positioner includes an angle control slide rail mounted on the two positioning plates and a locking mechanism for positioning the adjustable horn plate deflection angle.

[0015] As an improvement, the positioner may also include several positioning holes provided on the two positioning plates, and positioning pins provided on the adjustable horn plate for engaging with the positioning holes.

[0016] The beneficial effects of this invention compared with the prior art are: by adopting a hyperboloid horn plate structure, distortion caused by the "eddy current effect" due to "abrupt change" is reduced at the front outlet of the cylindrical wave converter 8. Attached Figure Description

[0017] Figure 1 The diagram below is a structural schematic of the existing technology, ZL201020112737.X.

[0018] Figure 2 It is a hyperbola geometry graph.

[0019] Figure 3This is a schematic diagram of a structure according to an embodiment of the present invention.

[0020] Figure 4 for Figure 3 A schematic diagram of a partial cross-sectional structure of the embodiment.

[0021] Figure 5 This is a schematic diagram of the positioning device in an embodiment of the present invention.

[0022] Figure 6 This is an application diagram of an embodiment of the present invention.

[0023] Figure 7 This is a schematic diagram illustrating the advantages of the present invention in controlling the "eddy current effect" compared to existing technologies.

[0024] Figure 8-12 This is a test diagram illustrating the technological advantages of the present invention compared to existing technologies. Detailed Implementation

[0025] The present invention will now be further described with reference to the accompanying drawings.

[0026] like Figure 1 As shown, the prior art, Chinese Utility Model Patent ZL201020112737.X, discloses a sound amplification device capable of arbitrarily changing the high-frequency directional coverage angle of a line sound source cylindrical wave. This device includes a tweeter driver 9, a sound amplification device, and a cylindrical wave converter 8 between the tweeter driver 9 and the sound amplification device. The sound amplification device is installed at the front outlet of the cylindrical wave converter 8. The sound amplification device includes a fixed plate 7, a rotating shaft 6, directional control plates 2, upper and lower positioning plates 1, and angle control slide rails 3 on the upper and lower positioning plates 1. There are two directional control plates 2, sandwiched between the upper and lower positioning plates 1. The two directional control plates 2 can rotate around the rotating shaft 6, changing the angle between them to adjust the high-frequency directional coverage angle of the line sound source cylindrical wave.

[0027] like Figure 2 The hyperbola shown is drawn according to the standard equation of a hyperbola: x^2 / a^2 - y^2 / b^2 = 1. The two vertices of the hyperbola, the intersections of the two hyperbolas with the X-axis, determine the XY coordinate axes. The line connecting the two vertices defines the X-axis, and the line passing through the midpoint of the two vertices and perpendicular to the X-axis is the Y-axis. Each hyperbola has corresponding asymptotes. The asymptote in the first and third quadrants, y2 = b / a*x, passes through the point (0, 0) and has a slope of b / a. The asymptote in the second and fourth quadrants, y1 = -b / a*x, passes through the point (0, 0) and has a slope of -b / a. The angle α between the asymptotes y1 and y2 is the maximum horizontal coverage angle achievable by this adjustable horizontal coverage angle cylindrical wave sound reinforcement device.

[0028] like Figure 3 The diagram illustrates an application example of the present invention. The speaker enclosure 10 comprises a bass horn 12 arranged on both sides of the enclosure and a tweeter horn 14 arranged in the center. A cylindrical wave adjustable horizontal coverage angle device 16 is installed at the front outlet of the cylindrical wave converter of the tweeter horn 14. The width of the front outlet of the cylindrical wave converter of the tweeter horn 14 is B, and its length is H.

[0029] like Figure 4 As shown, Figure 3 A partial cross-sectional structural diagram of the embodiment shows that the adjustable horizontal coverage angle device 16 for sound reinforcement is installed at the front outlet of the cylindrical wave converter of the tweeter 14. It is assembled from an adjustable horn plate 18, a rotating shaft 20, and a positioning device 22. The adjustable horizontal coverage angle device 16 has two adjustable horn plates 18 with hyperbolic shapes on the left and right sides. The cross-sectional shape of the adjustable horn plate 18 is hyperbolic, and the hyperbola conforms to the standard hyperbola equation: x^2 / a^2 - y^2 / b^2 = 1. In the standard hyperbola equation of the adjustable horn plate 18, the parameter a = B / 2, where B is the throat width of the horn 14 to which the adjustable horizontal coverage angle device 18 is adapted, i.e., the width B at the front outlet of the cylindrical wave converter of the tweeter 14. The throat width B of the adapted horn 14 satisfies the following equation: B ≤ C / 2fup, where C is the speed of sound (340 m / s) and fup is the upper limit of the effective high-frequency operation of the adapted horn. In the hyperbolic standard equation, the parameter b = a * tan(90° - α / 2), where α is twice the angle between the asymptote of the hyperbola and the Y-axis when the adjustable horizontal coverage angle device 16 for the sound reinforcement achieves its maximum horizontal coverage angle. The length H of the adjustable horn plate 18 is H = S / B, where S is the cross-sectional area of ​​the throat of the horn 14 adapted to the adjustable horizontal coverage angle device 16 for the sound reinforcement. The cross-sectional area of ​​the horn throat S = π × (C / 2πfo)2, where C is the speed of sound (340 m / s) and fo is the cutoff rate of the horn. Usually, the lower limit of the effective operating frequency fdown of the horn is set to fdown ≥ 2fo, and fdown is determined by the system crossover point and is a known parameter.

[0030] The pivot 20 is located at the vertex of the hyperbola. The line connecting the two vertices defines the X-axis, and the line passing through the midpoint of the two vertices and perpendicular to the X-axis is the Y-axis. The positioning device 22 comprises two positioning plates disposed on both ends of the adjustable horn plate 18 and a positioner 24. The positioner 24 can be configured as disclosed in the prior art, Chinese Utility Model Patent ZL201020112737.X, including angle control slide rails disposed on the two positioning plates and a locking mechanism for positioning the deflection angle of the adjustable horn plate. This configuration allows for continuous adjustment of the deflection angle of the adjustable horn plate 18.

[0031] The positioner 24 may also include several positioning holes 26 provided on the two positioning plates, and positioning pins provided on the adjustable horn plate 18 for engaging with the positioning holes. To facilitate the installation of the positioning pins, a vertical plate can be connected to the end face of the adjustable horn plate 18, and the positioning pins can be fixed to the vertical plate. The positioning pins can be elastic pins, which can retract when pressed and automatically pop out to position the deflection angle of the adjustable horn plate 18 when they reach the corresponding positioning hole.

[0032] like Figure 5 As shown, the structure of the positioning device 22 in the embodiment of the present invention can be further improved. By providing multiple rows of positioning holes 26 on the positioning plate, the number of selectable deflection angles of the adjustable horn plate 18 can be increased to meet different needs. In addition, by reducing the diameter of the positioning pin and the positioning hole, more positioning holes can be provided. Combined with the setting of multiple rows of positioning holes, more step adjustment options for the adjustable horn plate 18 can be achieved.

[0033] like Figure 6 As shown in the application diagram of the embodiment of the present invention, the two adjustable horn plates 18 can be set at different deflection angles to meet the needs of different occasions.

[0034] Figure 7 This is a schematic diagram demonstrating the advantages of this invention in controlling the "eddy current effect" compared to existing technologies. This invention employs a hyperboloid horn plate structure at the outlet of the cylindrical wave converter to reduce distortion caused by the "eddy current effect" resulting from "abrupt changes".

[0035] Figure 8-12 These are test diagrams illustrating the technological advantages of this invention compared to existing technologies. The left side of each test diagram shows the test results of the present invention, while the right side shows the test results of existing technologies. Each test includes two parts: the upper part is the frequency response curve, which expresses the relationship between sound intensity (SPL) and frequency. Theoretically, a flatter frequency response curve indicates better loudness consistency, more uniform energy, and less fluctuation in the loudspeaker's power. The lower part is the beamform, which (H…horizontal direction, V…vertical direction) is measured using a dedicated turntable tester and expresses the relationship between the sound wave diffusion angle and frequency. Theoretically, the effective coverage range is defined as the -6dB equal loudness range, and the angle formed between this range and the center of the sound source is the effective coverage angle (i.e., diffusion angle). Figure 8-11 It is a test in the horizontal direction, in which, Figure 8 It consists of two adjustable horn plates, each forming a 60° angle with the Y-axis. Figure 9 It consists of two adjustable horn plates, each forming a 45° angle with the Y-axis. Figure 10 It consists of two adjustable horn plates, each forming a 30° angle with the Y-axis. Figure 11The two adjustable horn plates are at angles of 60° and 45° to the Y-axis, respectively. These comparative tests show that, under the same speaker and technical parameters, the frequency response curves of this invention (hyperbolic horn plate) show less fluctuation in frequency response curve as the horn plate angle changes, compared to the prior art (linear horn plate). This indicates a more uniform energy distribution and fewer abrupt changes and distortions. The -6dB beamforming comparison shows that the effective coverage angle (H horizontal direction) of this invention (hyperbolic horn plate) is linearly consistent with the horn plate adjustment angle, and remains uniform across different frequencies. In contrast, the prior art (linear horn plate), due to sound reflection and eddy currents, leads to energy concentration and cancellation, resulting in larger frequency response fluctuations and poor beam uniformity. Figure 12 This test focuses on the vertical direction. Since the technical solution of this invention, namely the hyperbolic angle plate, and the existing technology, namely the linear angle plate, are both tested under the same conditions, both share the same cylindrical wave converter. According to the characteristics of cylindrical waves, in the H direction, the diffusion angle changes with the angle plate, while in the V direction it is not affected by the angle plate; therefore, the V-direction beam trends of both are similar. However, in the existing technology, the linear angle plate experiences local abrupt changes due to acoustic reflections from the top and bottom fixed plates.

[0036] An embodiment of the present invention discloses the following technical solution. (1) The throat width B of the tweeter horn is selected according to the preset technical parameter f of the sound reinforcement system. According to the algorithm for the minimum coupling distance of the sound source, B≤C / 2f, where C is the speed of sound 340 m / s, and f is the effective working upper limit of the horn at high frequencies, usually 16KHZ to 20KHZ. Therefore, B = 8.5mm to 10.625mm can be calculated, and the specific value is determined by the preset technical parameter of the sound reinforcement system. In this embodiment, the throat width B of the tweeter horn is selected as 10mm, and the corresponding effective working upper limit of the horn at high frequencies is f = 17KHZ. (2) The throat length H of the tweeter horn is selected according to the specifications of the matching mid-bass horn. Since the tweeter horn and mid-bass horn of the speaker are usually installed in the same enclosure, the throat length H of the tweeter horn can be selected by considering the size of the mid-bass horn and the space margin of the enclosure. For example, if a 10-inch speaker is selected for the mid-bass horn, the throat length H of the tweeter horn can be selected as 280mm. (3) Check whether the cutoff rate of the horn meets the acoustic performance requirements based on the horn mouth cross-sectional area. If necessary, the horn mouth cross-sectional area can be adjusted in reverse. First, the horn mouth cross-sectional area S = H * B. Second, according to known acoustic theory, the horn mouth cross-sectional area S = π × (C / 2πf₀)^2, where C is the speed of sound 340 m / s and f₀ is the horn cutoff rate. Usually, the lower limit of the effective operating frequency f₀ of the horn is set to f₀ ≥ 2f₀, and f₀ is determined by the system frequency division point, which is a known parameter. For example, in this embodiment, B = 10 mm, H = 280 mm, and correspondingly, the horn mouth cross-sectional area S = H * B = 2800 mm^2. The corresponding calculated cutoff rate f₀ of the horn is approximately 1.81 kHz, and the lower limit of the effective operating frequency f₀ of the system is ≥ 2f₀, which means the lower limit of the effective operating frequency f₀ is ≥ 3.62 kHz. If the lower limit of the effective operating frequency f of the speaker system does not meet the requirements, it is necessary to calculate the horn mouth cross-sectional area S and the horn throat length H according to the formula S=π×(C / 2πf。)^2, and adjust the size of the speaker and the specifications of the mid-bass horn. (4) Determine the hyperbolic parameter a according to the width B of the high-pitched horn throat. According to the formula parameter a=B / 2, in this embodiment, the width B of the high-pitched horn throat is 10mm, and the parameter a=5mm. (5) Calculate the hyperbolic parameter b according to the maximum horizontal coverage angle α required to be achieved by the cylindrical wave adjustable horizontal coverage angle device for sound reinforcement. According to the equation, the hyperbolic parameter b=a*tan(90°-α / 2), the hyperbolic parameter b can be calculated when the maximum horizontal coverage angle α is known. In this embodiment, the maximum horizontal coverage angle α is selected as 90°, the parameter a=5mm, and the parameter b=a*tan(90°-α / 2)=a*tan45°=a=5mm. Accordingly, the hyperboloid shape of the adjustable horn plate should conform to the hyperbolic equation x^2 / 5^2-y^2 / 5^2=1.

[0037] This invention provides an adjustable horizontal coverage angle device for cylindrical waves used in sound reinforcement. The device is installed at the front outlet of the cylindrical wave converter and is assembled from an adjustable horn plate, a rotating shaft, and a positioning device. The adjustable horn plate is hyperboloid in shape, and the deflection angle of the adjustable horn plate is set by the rotating shaft and the positioning device. This avoids the distortion caused by the flat-shaped directional control plate in the prior art. While facilitating the adjustment of the horizontal coverage angle of the cylindrical wave used in sound reinforcement, it also improves the sound quality of the amplified sound.

Claims

1. A cylindrical wave adjustable horizontal coverage angle device for sound reinforcement, the device being installed at the front outlet of a cylindrical wave converter, and assembled from an adjustable horn plate, a rotating shaft, and a positioning device, characterized in that... The adjustable horn plate is hyperboloid in shape, and its cross-sectional shape is hyperbolic. The hyperbola conforms to the standard equation of a hyperbola: x^2 / a^2-y^2 / b^2=1. The parameter of the standard equation of the hyperbola is a=B / 2, where B is the throat width of the horn adapted to the adjustable horizontal coverage angle device for sound reinforcement. The throat width B of the horn satisfies the following equation: B≤C / 2ƒup, where C is the speed of sound 340 m / s, and ƒup is the effective upper limit of the high frequency operation of the adapted horn. The parameter of the standard equation of the hyperbola is b=a*tan(90°-α / 2), where α is twice the angle between the asymptote of the hyperbola and the Y-axis when the adjustable horizontal coverage angle device for sound reinforcement achieves the maximum horizontal coverage angle.

2. The adjustable horizontal coverage angle device for cylindrical waves used in sound reinforcement according to claim 1, characterized in that: The adjustable horn plate length H = S / B, where S is the cross-sectional area of ​​the horn opening adapted to the adjustable horizontal coverage angle cylindrical wave device for sound reinforcement, and the cross-sectional area of ​​the horn opening S = π × (C / 2πƒ₀)^2, where C is the speed of sound 340 m / s, and ƒ₀ is the cutoff rate of the horn.

3. The adjustable horizontal coverage angle device for cylindrical waves used in sound reinforcement according to claim 1, characterized in that: The axis of rotation is located at the vertex of the hyperbola.

4. The adjustable horizontal coverage angle device for cylindrical waves used in sound reinforcement according to claim 1, characterized in that: The positioning device includes two positioning plates and a positioner disposed on both ends of the adjustable horn plate.

5. A cylindrical wave adjustable horizontal coverage angle device for sound reinforcement according to claim 4, characterized in that: The positioner includes an angle control slide rail mounted on the two positioning plates and a locking mechanism for positioning the deflection angle of the adjustable horn plate.

6. The adjustable horizontal coverage angle device for cylindrical waves used in sound reinforcement according to claim 4, characterized in that: The positioner includes several positioning holes disposed on the two positioning plates, and positioning pins disposed on the adjustable horn plate for engaging with the positioning holes.

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