Sound amplification system capable of controlling sound field range

Abstract

The invention provides a sound amplification system capable of controlling a sound field range. The sound amplification system comprises more than two sound amplification units and a pointing mechanism used for connecting and adjusting the sound amplification units. Wherein the sound amplification unit comprises a sound gathering cover and a linear sound source column loudspeaker arranged in the sound gathering cover, so that a sound field control system is formed, the diffusion range of sound waves is effectively controlled, and sound pollution and sound interference caused by sound leakage and sound dyeing can be effectively reduced. The pointing mechanism can adjust the sound field range according to the needs of the application scene.

Description

Technical Field

[0001] The present invention relates to a sound amplification device, and in particular to a sound amplification system with a controllable sound field range. The sound amplification system comprises two or more sound amplification units and a pointing mechanism for connecting and adjusting the sound amplification units. The sound amplification unit comprises a sound collecting cover and a linear sound source sound column arranged in the sound collecting cover, which constitutes a sound field control system, realizes effective control of the diffusion range of sound waves, and can effectively reduce sound pollution and sound interference caused by sound leakage and sound coloration. The pointing mechanism can adjust the sound field range according to the needs of the application scenario. Background Art

[0002] Theoretically, a point sound source is a spherical wave, and a line sound source is a cylindrical wave, and their transmission characteristics are essentially different. Figure 1 As shown in the figure, the wavefront generated by the point sound source 2 is a concentric sphere, which is called a spherical wave. Imagine that there is a spherical sound source in an infinite uniform medium, whose surface expands and contracts rapidly, and each point on the surface vibrates with the same phase and amplitude. The wave radiated to the surrounding medium is a spherical wave. This sound wave is spherically symmetric, that is, the magnitude of the sound pressure is only related to the distance from the center of the sphere. A sound source of any shape, as long as its size is much smaller than the wavelength, can be regarded as a point sound source and radiates spherical waves. For spherical waves, the sound intensity at any distance from the sound source is inversely proportional to the square of the distance, the sound pressure is inversely proportional to the distance, and the phase difference between the sound pressure and the vibration velocity is inversely proportional to the ratio of the radius of the spherical wave to the wavelength.

[0003] like Figure 2 As shown in the figure, the wavefront generated by the line sound source 4 is a coaxial cylindrical wave, which is called a cylindrical wave. A cylindrical wave is a wave whose wavefront is a coaxial cylindrical wave. Imagine that there is an infinitely long uniform line sound source in an infinitely uniform medium, and the wave it generates is an ideal cylindrical sound wave. In a cylindrical sound wave, the sound pressure amplitude is uniformly distributed along the axial direction, and is inversely proportional to the square root of the distance from the axis along the radial direction. Its radial sound intensity is inversely proportional to the first power of the distance from the axis.

[0004] From the above acoustic theory analysis, it can be seen that the acoustic characteristics of the line sound source composed of cylindrical waves are far superior to the point sound source composed of traditional point spherical waves. Specifically, it is manifested in: 1. Transmission characteristics, efficiency is twice as high. 2. Good coupling characteristics, low distortion caused by interference. 3. Better directivity control (strong directivity in the vertical direction). Therefore, how to realize the conversion of spherical waves into cylindrical waves has become the main focus of researchers in this industry.

[0005] Prior art, Chinese patent application, CN202210427881.X, discloses an adjustable vertically directed sound amplification column. This technology forms a line sound source sound column through a row of coaxial cylindrical wave mid-high frequency speakers.

[0006] In actual sound reinforcement applications, there are many occasions where the sound reinforcement range needs to be precisely controlled to reduce the interference caused by the mutual influence of various sound sources. For example, in museums and exhibition halls, there are zoning sound control requirements, or in square dance venues, where disputes over sound pollution and nuisance often occur due to the uncontrollable sound field range. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a sound amplification system with a controllable sound field range. The sound amplification system is composed of two or more sound amplification units and a directional mechanism for connecting and adjusting the sound amplification units. The sound amplification units perform three-dimensional control on the diffusion of sound waves through a combination of a sound focusing hood and a line sound source sound column arranged in the sound focusing hood, thereby achieving precise control of the sound field range.

[0008] The invention provides a sound amplification system with controllable sound field range, comprising more than two sound amplification units and a directional mechanism for connecting and adjusting the sound amplification units.

[0009] As an improvement, the sound amplification unit includes a sound collecting cover and a linear sound source sound column arranged in the sound collecting cover.

[0010] As an improvement, the line sound source sound column includes a mid-high frequency sound column and a low frequency sound column arranged back to back, and the low frequency sound column faces the opening direction of the sound focusing cover.

[0011] As an improvement, the cross-section of the sound focusing cover presents a first-order parabola, the acoustic center point of the mid- and high-frequency sound column is at the focus of the first-order parabola, the opening width of the first-order parabola is equal to the wavelength corresponding to the mid- and low-frequency crossover frequency, and the first-order parabola expands along the axis of the linear sound source sound column to form a first-order parabola, and the first-order parabola constitutes the inner surface of the sound focusing cover.

[0012] Furthermore, the cross-section of the sound focusing cover presents a second-order combined parabola, the acoustic center point of the mid-high frequency sound column is at the focus of the first-order parabola, the opening width of the first-order parabola is equal to the wavelength corresponding to the mid-low frequency crossover frequency, the acoustic center of the low-frequency sound column is at the focus of the second-order parabola, the opening width of the second-order parabola is equal to the wavelength corresponding to the lower limit of the controllable frequency of the low-frequency sound column, the first-order parabola intersects with the second-order parabola at the intersection, the second-order combined parabola is composed of the first-order parabola before the intersection and the second-order parabola after the intersection, the second-order combined parabola expands along the axis of the line sound source sound column to form a second-order combined parabola, and the second-order combined parabola constitutes the inner surface of the sound focusing cover.

[0013] As an improvement, the pointing mechanism is an I-shaped connecting mechanism.

[0014] Compared with the prior art, the beneficial effects brought by the present invention are as follows: (1) The linear sound source sound column is used to realize the control of sound wave diffusion along the axis direction of the linear sound source sound column. As the length of the axis of the sound column increases, the lower limit of the controllable frequency will decrease. (2) The sound focusing effect of the sound focusing hood is used to realize the control of sound waves in the opening direction of the sound focusing hood. The diffusion control of medium and high frequency sound waves is realized by the first-order parabola, and the diffusion control of low frequency sound waves is realized by the second-order parabola. (3) The sound reflection effect of the sound focusing hood is used to realize the diffusion control of sound waves in the axis direction of the second-order combined parabola. Finally, the sound pressure difference of the sound field inside and outside the sound focusing hood can be realized to be ≥25dB. (4) The pointing mechanism can adjust the sound field range according to the needs of the application scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of a point sound source and a spherical wave.

[0016] Figure 2 Schematic diagram of line sound source and cylindrical wave.

[0017] Figure 3A and Figure 3B It is a schematic diagram of the structure of a line sound source sound column in one embodiment of the present invention.

[0018] Figure 4 FIG. 1 is a schematic diagram of the cross-sectional structure of a sound amplification unit in one embodiment of the present invention.

[0019] Figure 5 This is a test curve of the sound pressure of the sound field inside and outside the sound collecting cover according to an embodiment of the present invention.

[0020] Fig. 6A , 6B It is a schematic diagram of a pointing mechanism in one embodiment of the present invention.

[0021] Fig. 7A , 7B It is a schematic diagram of controlling the sound field range by a pointing mechanism in one embodiment of the present invention.

[0022] Fig. 8A , 8B It is a schematic diagram of controlling the sound field range by a pointing mechanism in one embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] like Figure 1, schematic diagram of a point sound source and a spherical wave, as shown, the wavefront generated by the point sound source 2 is a concentric sphere, which is called a spherical wave. Imagine that there is a spherical sound source in an infinite uniform medium, whose surface expands and contracts rapidly, and each point on the surface vibrates with the same phase and amplitude, and the wave radiated to the surrounding medium is a spherical wave. This sound wave is spherically symmetric, that is, the magnitude of the sound pressure is only related to the distance from the center of the sphere. A sound source of any shape, as long as its size is much smaller than the wavelength, can be regarded as a point sound source, radiating spherical waves. For spherical waves, the sound intensity at any distance from the sound source is inversely proportional to the square of the distance. As shown in the figure, when the distance from the sound source increases from R to R2, which is twice R, the area of ​​the wavefront increases from A to 4A, and the sound intensity drops to 1 / 4.

[0025] like Figure 2 , schematic diagram of a line sound source and a cylindrical wave, as shown, the wavefront generated by the line sound source 4 is a coaxial cylindrical wave, which is called a cylindrical wave. A cylindrical wave is a wave whose wavefront is a coaxial cylindrical wave. Imagine that there is an infinitely long uniform line sound source in an infinitely uniform medium, and the wave it generates is an ideal cylindrical sound wave. In a cylindrical sound wave, the sound pressure amplitude is uniformly distributed along the axial direction, and is inversely proportional to the square root of the distance from the axis along the radial direction. Its radial sound intensity is inversely proportional to the first power of the distance from the axis. As shown in the figure, when the sound source distance increases from R to R2, which is twice R, the area of ​​the wavefront increases from A to 2A, and the sound intensity drops to 1 / 2.

[0026] like Figure 3A and Figure 3B , schematic diagram of the structure of the line sound source column, where Figure 3A is a side view, Figure 3B It is a front view. In one embodiment of the present invention, a line sound source sound column 6 includes a mid-high frequency sound column 8 and a low frequency sound column 10 arranged back to back, and the low frequency sound column 10 faces the opening direction of the sound focusing cover (not shown). The mid-high frequency sound column 8 is composed of a row of 6 coaxial mid-high frequency horns 12, and the low frequency sound column 10 is composed of a row of 4 low frequency horns 14. The axis 16 of the mid-high frequency horn 12 is parallel to the axis 18 of the low frequency horn 14, and is in the same plane as the axis 20 of the line sound source sound column 6, the mid-high frequency sound column 8, and the low frequency sound column 10.

[0027] Figure 4 The cross-sectional structure diagram of a sound amplifying unit in one embodiment of the present invention. The cross-sectional diagram crosses the axis of the length direction of the sound amplifying unit 22, that is, the axis of the line sound source sound column, so a coaxial mid-high frequency horn 12 and a low frequency horn 14 are shown in the figure, and the mid-high frequency horn 12 and the low frequency horn 14 are arranged back to back, and the low frequency horn 14 faces the opening direction of the sound focusing cover 24. The axis 16 of the mid-high frequency horn 12 and the axis 18 of the low frequency horn 14 are parallel to each other, so the axis 16 and the axis 18 are shown to be collinear in the cross-sectional diagram.

[0028] Figure 4It further illustrates the design of the second-order combined parabola on the inner surface of the sound-collecting cover 24. In the cross-sectional view, the sound-collecting cover 24 is in the shape of a thin shell, and the cross-section of the sound-collecting cover 24 presents a second-order combined parabola. The mid-high frequency sound column, that is, the acoustic center point F1 of the mid-high frequency horn 12 is at the focus of the first-order parabola P1, and the opening width L1 of the first-order parabola P1 is equal to the wavelength corresponding to the mid-low frequency crossover frequency. The low-frequency sound column, that is, the acoustic center F2 of the low-frequency horn 14 is at the focus of the second-order parabola P2, and the opening width L2 of the second-order parabola P2 is equal to the wavelength corresponding to the lower limit of the controllable frequency of the low-frequency sound column. The first-order parabola P1 and the second-order parabola P2 intersect at the intersection C. The second-order combined parabola is composed of the first-order parabola P1 before the intersection C (i.e., the left side of point C in the figure) and the second-order parabola P2 after the intersection C (i.e., the right side of point C in the figure). The second-order combined parabola expands along the axis of the linear sound source sound column to form a second-order combined parabola, and the second-order combined parabola constitutes the inner surface of the sound focusing cover.

[0029] Correspondingly, if a second-order parabola is not set, the cross-section of the sound focusing cover will present a first-order parabola, the acoustic center point of the mid- and high-frequency sound column will be at the focus of the first-order parabola, the opening width of the first-order parabola will be equal to the wavelength corresponding to the mid- and low-frequency crossover frequencies, and the first-order parabola will expand along the axis of the linear sound source sound column to form a first-order parabola, which will constitute the inner surface of the sound focusing cover.

[0030] The design steps of the sound amplification unit of the present invention mainly include:

[0031] (1) Determine the structure and dimensions of the sound column. According to the requirements of the sound amplification technical indicators under the actual application conditions, select the low, medium and high frequency horns, set the crossover frequency, and determine the dimensions of the sound column and the frequency response range of the controllable sound field according to the specifications of the horns.

[0032] (2) Calculate the crossover frequency. According to the line source theory, the acoustic center distance between two adjacent horns should be less than or equal to half the wavelength corresponding to the coupling upper limit frequency. Considering that the acoustic center distance between two adjacent horns is approximately equal to the diameter of the horn, the crossover frequency can be determined according to the specifications of the selected horn. For example, the crossover frequency between low frequency and mid-frequency can be calculated based on the diameter of the low-frequency horn, and the crossover frequency between mid-frequency and high frequency can be calculated based on the diameter of the mid-frequency horn.

[0033] (3) Determine the acoustic center of the mid-high frequency horn and the low frequency horn. Theoretically, the acoustic center of the horn is located at the center of the voice coil. The mid-high frequency horn uses a coaxial mid-high frequency horn, and through electronic delay compensation, its coupled acoustic center is located in the middle of the center point of the mid-frequency horn and the high frequency horn. The acoustic center of the low frequency horn is located at the center of the low frequency horn voice coil.

[0034] (4) Determine the second-order combined parabola of the sound-collecting enclosure. According to acoustic theory, the size of the baffle is approximately equal to the wavelength of the controllable frequency. Therefore, it can be deduced that the opening width L1 of the first-order parabola is equal to the wavelength corresponding to the crossover frequency between the low-frequency and mid-frequency. In addition, the acoustic center F1 of the mid- and high-frequency horn is at the focus of the first-order parabola P1. From this, the shape of the first-order parabola P1 corresponding to the mid- and high-frequency horn can be determined. Similarly, the opening width L2 of the second-order parabola P2 is equal to the wavelength corresponding to the lower limit of the controllable frequency of the low-frequency sound column. In addition, the acoustic center F2 of the low-frequency horn is at the focus of the second-order parabola P2. From this, the shape of the second-order parabola P2 corresponding to the low-frequency horn can be determined. Afterwards, the first-order parabola P1 intersects the second-order parabola P2 at the intersection C. The second-order combined parabola is composed of the first-order parabola P1 before the intersection C (i.e., the left side of point C in the figure) and the second-order parabola P2 after the intersection C (i.e., the right side of point C in the figure). The second-order combined parabola expands along the axis of the linear sound source sound column to form a second-order combined parabola, and the second-order combined parabola constitutes the inner surface of the sound focusing cover.

[0035] Correspondingly, if a second-order parabola is not set, the cross-section of the sound focusing cover will present a first-order parabola, the acoustic center point of the mid- and high-frequency sound column will be at the focus of the first-order parabola, the opening width of the first-order parabola will be equal to the wavelength corresponding to the mid- and low-frequency crossover frequencies, and the first-order parabola will expand along the axis of the linear sound source sound column to form a first-order parabola, which will constitute the inner surface of the sound focusing cover.

[0036] (5) Combined focus. In actual assembly, actual focus measurement is required to ensure that the acoustic center F1 of the mid-high frequency horn is at the focus of the first-order parabola P1, and the acoustic center F2 of the low frequency horn is at the focus of the second-order parabola P2. Accordingly, when the specifications of the focusing hood are fixed, the positions of the mid-high frequency horn and the low frequency horn can be fine-tuned to meet the focus requirements.

[0037] (6) Confirmation by actual measurement. After measuring the sound pressure difference inside and outside the sound-concentrating hood and reaching the design target, the design scheme can be confirmed, and the mold can be opened for mass production.

[0038] (7) Assembly application: According to the requirements of the application, two or more sound amplification units can be connected through a pointing mechanism, and the sound field range can be adjusted through a hinge.

[0039] Figure 5This is a test curve of the sound pressure of the sound field inside and outside the sound collecting cover of an embodiment of the present invention. In the figure, curve A is the test curve of the sound pressure of the sound field inside the sound collecting cover, and curve B is the test curve of the sound pressure of the sound field outside the sound collecting cover. The test curves show that (1) the sound pressure of the sound field inside the sound collecting cover is generally greater than the sound pressure of the sound field outside the sound collecting cover, indicating that the sound collecting cover has the function of reducing sound leakage. (2) In a characteristic frequency band, such as the 5K to 10K Hz frequency band, the sound pressure of the sound field inside the sound collecting cover is about 30dB greater than the sound pressure of the sound field outside the sound collecting cover, indicating that the ability of the sound collecting cover to reduce sound leakage is stronger in this frequency band.

[0040] Fig. 6A , 6B is a schematic diagram of a pointing mechanism in one embodiment of the present invention, wherein Fig. 6A , 6B It is a top view and a front view of the pointing mechanism. Fig. 6A In the figure, the pointing mechanism 26 is an I-shaped connecting mechanism, including two connecting plates 28 in the form of strips, and a fixing plate 30 connected to the connecting plates. The connecting plates 28 are used to connect to the opening of the sound collecting cover (not shown), and the two ends of the fixing plate 30 are connected to the middle of the connecting plates 28. Figure 6B In the embodiment, the fixing plate 30 is in a “+” shape, and a middle space of the “+” shape of the fixing plate 30 is used to accommodate a sound collecting cover (not shown).

[0041] Fig. 7A , 7B FIG. 1 is a schematic diagram of controlling the sound field range by a pointing mechanism in one embodiment of the present invention. Fig. 7A As shown, a sound amplification system 32 with a controllable sound field range includes three sound amplification units 22 and a pointing mechanism 26 for connecting and adjusting the sound amplification units. The pointing mechanisms 26 are connected by hinges 34. Figure 7B As shown, the three sound amplification units 22 are mutually deflected at a certain angle X via the hinge 34, and accordingly, the controllable sound field range is expanded.

[0042] Fig. 8A , 8B FIG. 1 is a schematic diagram of controlling the sound field range by a pointing mechanism in one embodiment of the present invention. Fig. 8A As shown, a sound amplification system 32 with a controllable sound field range includes three sound amplification units 22 and a pointing mechanism 26 for connecting and adjusting the sound amplification units. The pointing mechanisms 26 are connected by hinges 34. Figure 8B As shown, the three sound amplification units 22 are mutually deflected at a certain angle X via the hinge 34, and accordingly, the controllable sound field range is expanded.

Claims

1. A sound amplification system with controllable sound field range, comprising two or more sound amplification units and a directional mechanism for connecting and adjusting the sound amplification units.

2. A sound reinforcement system with controllable sound field range according to claim 1, characterized in that The sound amplification unit comprises a sound collecting cover and a line sound source sound column arranged in the sound collecting cover.

3. A sound reinforcement system with controllable sound field range according to claim 2, characterized in that The line sound source sound column comprises a mid-high frequency sound column and a low frequency sound column arranged back to back, and the low frequency sound column faces the opening direction of the sound focusing cover.

4. A sound amplification system with controllable sound field range according to claim 3, characterized in that The cross-section of the sound focusing cover presents a first-order parabola, the acoustic center point of the mid-high frequency sound column is at the focus of the first-order parabola, the opening width of the first-order parabola is equal to the wavelength corresponding to the mid-low frequency crossover frequency, and the first-order parabola expands along the axis direction of the linear sound source sound column to form a first-order parabola, and the first-order parabola constitutes the inner surface of the sound focusing cover.

5. A sound reinforcement system with controllable sound field range according to claim 3, characterized in that The cross-section of the sound focusing cover presents a second-order combined parabola, the acoustic center point of the mid-high frequency sound column is at the focus of the first-order parabola, the opening width of the first-order parabola is equal to the wavelength corresponding to the mid-low frequency crossover frequency, the acoustic center of the low-frequency sound column is at the focus of the second-order parabola, the opening width of the second-order parabola is equal to the wavelength corresponding to the lower limit of the controllable frequency of the low-frequency sound column, the first-order parabola intersects with the second-order parabola at the intersection, the second-order combined parabola is composed of the first-order parabola before the intersection and the second-order parabola after the intersection, the second-order combined parabola expands along the axis direction of the linear sound source sound column to form a second-order combined parabola, and the second-order combined parabola constitutes the inner surface of the sound focusing cover.

6. A sound amplification system with controllable sound field range according to claim 1, characterized in that The pointing mechanism is an I-shaped connecting mechanism.

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