A double-row linear loudspeaker array driving method

Abstract

The present invention discloses a double-row linear speaker array driving method, which relates to the technical field of sound reinforcement systems; the method is based on a computer, a signal processing module, a power amplifier and a speaker array that are electrically connected in sequence, and includes a driving step, wherein the speaker array is a double-row linear speaker array, and the driving step includes combining a wave field synthesis algorithm WFS and a distance-based amplitude translation algorithm DBAP, obtaining the frequency domain of a first single-row linear speaker array according to formula 9, and obtaining the frequency domain of a second single-row linear speaker array according to formula 10, and then calculating and obtaining a driving signal for each speaker; through the double-row linear speaker array, the wave field synthesis algorithm WFS and the distance-based amplitude translation algorithm DBAP are combined to obtain a driving signal for each speaker, and then, when the wave field is synthesized, the effect of expanding the sense of space in the vertical direction is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of sound amplification systems, and in particular to a double-row linear loudspeaker array driving method. Background Art

[0002] Wave Field Synthesis, abbreviated as WFS, is a spatial audio rendering technology that aims to achieve realistic three-dimensional sound field reproduction by simulating the physical principles of sound wave propagation. Its function is to create directional and localized sounds in a specific auditory space, so that the audience can feel the sound sources from different directions and positions. WFS uses a speaker array combined with signal processing to emit sound from multiple speakers with accurate phase and amplitude distribution to simulate the propagation and reflection of sound waves in a real environment. Wave field synthesis has important applications in music production, movie sound effects, game audio and other fields. It can provide rich and realistic sound effects for concerts, theaters, cinemas, game scenes, etc., and enhance the sensory experience of the audience.

[0003] Wave field synthesis needs to cooperate with speaker arrays to reproduce three-dimensional sound fields. At present, the speaker arrays used for wave field synthesis mainly include: planar speaker arrays, linear speaker arrays and circular speaker arrays. Among them, the planar speaker array needs to form a surface with many speakers. This planar speaker array can cover a wider range, so that more listeners can get a good sound field experience. Although this speaker array can produce better sound field effects, it requires a large number of speakers, high cost, and large space requirements; the circular speaker array is arranged in a circular shape as a whole, so that the audience can get a consistent sound experience in the entire circular area, and the circular array can achieve a more natural and smooth sound diffusion, so that the sound surrounds the audience and provides an immersive auditory experience, but the sound radiation of the circular array is mainly along its axis direction, and the audience inside the ring may feel the unevenness of the sound; the linear speaker array requires fewer speakers than the planar speaker array and the circular speaker array. The linear array can achieve accurate sound positioning and sense of direction, provide precise sound field effects, and the linear array can be arranged on the wall or ceiling relatively easily, suitable for various application scenarios.

[0004] Currently, there are cases where speaker arrays are used to achieve wave field synthesis.

[0005] The authorization announcement number is CN114245273B, and its name is a beam projection method based on a high-low frequency division multi-speaker array. This method uses multiple speaker arrays to form an effective beam in a wider frequency range, thereby improving the overall spatial surround feeling. However, this method can only achieve the playback effect in the horizontal plane where the speaker array is located, and cannot achieve the spatial expansion effect in the vertical direction of the plane where the speaker array is located.

[0006] The authorization announcement number is CN218041758U, and the name is a directional sound amplification speaker. This method solves the low-frequency diffraction problem by separately designing the structures of the front and rear speakers to ensure that the speaker array has good directivity. However, this method only improves the structure of the speaker and does not involve related wave field synthesis methods.

[0007] The authorization announcement number is CN115038010B, and the name is a sound field reconstruction control method and system based on a speaker array. The sound field can be changed and adjusted according to scene changes, but only the sound field reconstruction effect of the plane where the speaker array is located is discussed, and the sound field reconstruction effect in the vertical direction of the plane where the speaker array is located is not involved.

[0008] According to the relevant theoretical basis of WFS, when using a horizontal linear speaker array for sound field synthesis, listeners can only hear effective wavefronts in the horizontal direction, and the synthesized wave field is not accurate enough in the vertical direction. The wavelength synthesis of a single-row linear speaker array only produces a wavelength synthesis effect in the horizontal plane where the speaker array is located, and cannot produce a wavelength synthesis effect in the y-axis direction of the speaker array. If you want to expand the virtual source space in the vertical direction, using a single-row horizontal linear speaker array is far from enough. Summary of the invention

[0009] The invention provides a double-row linear loudspeaker array driving method to solve the technical problem that the synthesized wave field has a poor spatial sense in the vertical direction.

[0010] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0011] A double-row linear speaker array driving method is based on a computer, a signal processing module, a power amplifier and a speaker array that are electrically connected in sequence, and includes a driving step, wherein the speaker array is a double-row linear speaker array, and the double-row linear speaker array includes two single-row linear speaker arrays with the same structure, namely a first single-row linear speaker array and a second single-row linear speaker array, and the first single-row linear speaker array is parallelly distributed and aligned with the second single-row linear speaker array; the driving step includes combining a wave field synthesis algorithm WFS and a distance-based amplitude translation algorithm DBAP, obtaining a frequency domain of the first single-row linear speaker array according to formula 9, and obtaining a frequency domain of the second single-row linear speaker array according to formula 10, and then calculating and obtaining a driving signal for each speaker;

[0012] Formula 9: ;

[0013] In formula 9, H 1n (ω) is the frequency domain expression of the first single-row linear speaker array; g1 is the gain value of the source distance from the first single-row linear speaker array; |A 1n (ω) | is H 1n (ω); 1n is the speaker identifier, where 1 represents the first row and n represents the nth speaker; ω is the circular frequency, j is the imaginary unit, φ n is the phase angle of the signal of the nth loudspeaker;

[0014] Formula 10: ;

[0015] In formula 10, H 2n (ω) is the frequency domain expression of the second single-row linear speaker array; g2 is the gain value of the source distance from the second single-row linear speaker array; |A 2n (ω)| is H 2n (ω) amplitude; 2n is the speaker identifier, where 2 represents the second row, n represents the nth speaker, ω is the circular frequency, j is the imaginary unit, φ n is the phase angle of the signal of the nth loudspeaker.

[0016] A further technical solution is that the second single-row linear speaker array is located above the first single-row linear speaker array to form a double-row horizontal linear speaker array.

[0017] A further technical solution is that the second single-row linear speaker array is located on one side of the first single-row linear speaker array to form a double-row longitudinal linear speaker array.

[0018] A further technical solution is that the single-row linear speaker array includes fourteen speakers, and the fourteen speakers are sequentially arranged in a horizontal straight line to form a single-row linear speaker array.

[0019] A further technical solution is that: in the driving step, the driving function of each speaker in the first single-row linear speaker array and the second single-row linear speaker array is respectively,

[0020] Formula 11: ;

[0021] In formula 11, Q1(r n ,ω) is the frequency domain expression of the driving signal of each loudspeaker in the first single-row linear loudspeaker array, S(ω) is the original driving signal spectrum, in dB; r n is the position coordinate of the nth loudspeaker in polar coordinates;

[0022] Formula 12: ;

[0023] In formula 12, Q2(r n ,ω) is the frequency domain expression of the driving signal of each loudspeaker in the second single-row linear loudspeaker array.

[0024] A further technical solution is to also include a synthesis step, wherein the synthesis step includes all loudspeakers realizing wave field synthesis according to corresponding driving signals and expanding the effect of spatial sense in the vertical direction.

[0025] A further technical solution is that: in the driving step,

[0026] Formula 4: ;

[0027] In formula 4, d1 is the vertical distance between the source and the first single-row linear speaker array (103) in the y-axis direction; y m is the coordinate value of the source in the y direction;

[0028] Formula 5: ;

[0029] In formula 5, d2 is the vertical distance between the source and the second single-row linear speaker array (104) in the y-axis direction, and H is the vertical center distance between the first single-row linear speaker array (103) and the second single-row linear speaker array (104);

[0030] Assuming that the amplitude translation gain of each loudspeaker in the first single-row linear loudspeaker array (103) is g1, and the amplitude translation gain of each loudspeaker in the second single-row linear loudspeaker array (104) is g2, the gain formula is expressed as Formula 6;

[0031] Formula 6: ;

[0032] In formula 6, g iis the gain value of the driving signal of the row of speaker arrays closer to the source in the two rows of speaker arrays. The gain value is a scalar and has no direction. i is the serial number of the single-row linear speaker array, and l is the normalization coefficient, which depends on the vertical distance between the source and the two rows of speaker arrays.

[0033] The calculation formulas of l and a are expressed as:

[0034] Formula 7: ;

[0035] Formula 8: ;

[0036] In formula 8, a represents the coefficient of R attenuation in decibels for every doubling of the distance.

[0037] The beneficial effects of adopting the above technical solution are:

[0038] A double-row linear speaker array driving method is based on a computer, a signal processing module, a power amplifier and a speaker array that are electrically connected in sequence, and includes a driving step, wherein the speaker array is a double-row linear speaker array, and the double-row linear speaker array includes two single-row linear speaker arrays with the same structure, namely a first single-row linear speaker array and a second single-row linear speaker array, and the first single-row linear speaker array and the second single-row linear speaker array are parallelly distributed and aligned; the driving step includes combining a wave field synthesis algorithm WFS with a distance-based amplitude translation algorithm DBAP, obtaining the frequency domain of the first single-row linear speaker array according to formula 9, and obtaining the frequency domain of the second single-row linear speaker array according to formula 10, and then calculating and obtaining the driving signal of each speaker. It combines the wave field synthesis algorithm WFS with the distance-based amplitude translation algorithm DBAP through the double-row linear speaker array to obtain the driving signal of each speaker, and then achieves the effect of expanding the sense of space in the vertical direction during wave field synthesis.

[0039] Please refer to the detailed description of the specific implementation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a distribution diagram of the installation space of the loudspeaker array of the present invention;

[0041] Figure 2 yes Figure 1 The distribution diagram of the xy plane;

[0042] Figure 3 yes Figure 1 The distribution diagram of the xz plane;

[0043] Figure 4 It is a principle block diagram of the present invention;

[0044] Figure 5The present invention uses COMSOL finite element simulation at a single frequency of 1600 Hz, with the virtual source y-direction coordinate value being 10 mm, and the sound pressure distribution diagram on the yz plane;

[0045] Figure 6 The present invention uses COMSOL finite element simulation at a single frequency of 1600 Hz, with the virtual source y-direction coordinate value being 300 mm and the sound pressure distribution diagram on the yz plane;

[0046] Figure 7 The present invention uses COMSOL finite element simulation at a single frequency of 1600 Hz, with the y-direction coordinate value of the virtual source being 490 mm and the sound pressure distribution diagram on the yz plane. DETAILED DESCRIPTION

[0047] The present application is a double-row linear speaker array driving method. The method is based on the wave field synthesis theory and solves the technical problem of insufficient spatial expansion of virtual sources in the vertical direction of wave field synthesis of a single-row horizontal linear speaker array by expanding the horizontal linear speaker array in the vertical direction. The method is not only simple in design, but also can achieve the effect of expanding the sense of space in the vertical direction with a small number of speakers. It particularly refers to a speaker array with two rows of horizontal straight lines.

[0048] The purpose of the present application is achieved in this way: utilizing the characteristic that a single-row horizontal linear speaker array can perform wave field synthesis in a plane, the same horizontal linear speaker array is placed side by side at the bottom and top, wherein the position of the virtual source is controlled by wave field synthesis in the horizontal and depth directions, and the position of the virtual source is controlled by amplitude translation in the vertical direction. The vertical distance between the virtual source and the bottom and top linear speaker arrays is calculated. If the virtual source is close to the top array, when performing wave field synthesis signal processing, the overall signal amplitude of the bottom linear speaker array is attenuated, and the overall signal amplitude of the top linear speaker array is enhanced. This processing method combining wave field synthesis and amplitude translation can achieve the spatial expansion effect of the virtual source in the vertical direction.

[0049] The two-row horizontal linear speaker array mainly refers to a single-row horizontal linear speaker array that is vertically shifted by a certain distance to form two-row linear speaker arrays, wherein the size and number of speakers in the two-row linear speaker array are equal, and the distance between every two speakers in each row of the linear speaker array is equal.

[0050] This application uses the wave field synthesis algorithm WFS, and the speaker array used is a speaker array arranged in a horizontal straight line, which can achieve a two-dimensional sound field reconstruction effect. In order to achieve spatial expansion in the vertical direction, a double-row linear speaker array is used, and then the distance-based amplitude shift algorithm DBAP is used to control the sound pressure amplitude of each row of speaker arrays to achieve the spatial expansion effect of wave field synthesis in the vertical direction.

[0051] Beneficial technical effects of the present application: The method provided by the present application utilizes a double-row horizontal linear arrangement of speaker arrays, combined with a wave field synthesis algorithm WFS and a distance-based amplitude shift algorithm DBAP, to achieve the effect of virtual source spatial expansion in the vertical direction of wave field synthesis using a smaller number of speakers. And the vertical position of the wave field synthesis will change with the change of the vertical position of the virtual source, so that the listener can feel the change in the vertical position of the sound field, and enhance the spatial sense of the sound field. In addition, the use of the distance-based amplitude shift algorithm DBAP to achieve vertical spatial expansion of wave field synthesis will not introduce more speakers, which reduces the corresponding cost and makes the effect easier to achieve.

[0052] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0054] Embodiment 1:

[0055] like Figure 1 to Figure 4 As shown, the present invention discloses a double-row linear speaker array driving method, based on a computer, a signal processing module, a power amplifier and a speaker array electrically connected in sequence, including a driving step, wherein the speaker array is a double-row linear speaker array.

[0056] like Figure 4 As shown, there is corresponding control software in the computer, which is the existing technology. The control software can perform algorithm calculation and modify the position of the virtual source in real time. The signal processing module is used to output the processed sound signal in real time. The processed sound signal is output to the speaker array through the power amplifier, and the speaker array generates a sound signal synthesized by wave field.

[0057] The whole process is as follows: LabVIEW software is used for algorithm calculation, and a PXI chassis is used in conjunction with LabVIEW. A data acquisition card is placed in the chassis to form a data acquisition device. The data acquisition device is connected to a computer. The data acquisition card is the signal processing module. Here, the data acquisition card can output the processed sound signal. The data acquisition card can be directly connected to a power amplifier, and the power amplifier is connected to a loudspeaker. The sound signal mentioned here is not a sound wave, but a sound signal that generates a sound wave. It is a signal. The sound signal is output from the acquisition card described above. The sound pressure refers to the actual sound generated by the sound signal output from the acquisition card after being amplified by the power amplifier and output to the loudspeaker. The sound signal mentioned in this application is not sound pressure.

[0058] In the technical solution of the present application, different speakers have different driving signals, each speaker generates a different sound pressure signal, and all speakers emit sound together to generate a synthetic sound field in the space.

[0059] like Figure 1 As shown, the double-row linear speaker array includes two single-row linear speaker arrays with the same structure, namely a first single-row linear speaker array 103 and a second single-row linear speaker array 104. The single-row linear speaker array includes fourteen speakers, and the fourteen speakers are sequentially arranged in a horizontal straight line to form a single-row linear speaker array. The first single-row linear speaker array 103 and the second single-row linear speaker array 104 are distributed in parallel and aligned, and the second single-row linear speaker array 104 is located above the first single-row linear speaker array 103, forming a double-row horizontal linear speaker array. The first single-row linear speaker array 103 and the second single-row linear speaker array 104 are both fixed above the ground 101. The vertical center distance between the first single-row linear speaker array 103 and the second single-row linear speaker array 104 is H, that is, the two rows of linear speaker arrays are installed according to the vertical center distance H. The first single-row linear speaker array 103 is located at the bottom and corresponds to the bottom linear speaker array. The second single-row linear speaker array 104 is located at the top and corresponds to the top linear speaker array. The z-axis coordinates of the first single-row linear speaker array 103 and the second single-row linear speaker array 104 are both 0. A single speaker 102 and a source 105, that is, the source is located between the first single-row linear speaker array 103 and the second single-row linear speaker array 104. The first single-row linear speaker array 103 and the second single-row linear speaker array 104 have the same sound emission direction.

[0060] like Figure 2As shown, the horizontal center distance between two adjacent speakers in the first single-row linear speaker array 103 and the second single-row linear speaker array 104 is d=80 mm, the center coordinates of the first speaker on the left in the first single-row linear speaker array 103 are set to (0,0,0), the first single-row linear speaker array 103 and the second single-row linear speaker array 104 are parallelly distributed and aligned, that is, the corresponding upper and lower speaker centers in the first single-row linear speaker array 103 and the second single-row linear speaker array 104 are aligned in the vertical direction, and the center coordinates of the first speaker on the left in the second single-row linear speaker array 104 are (0,H,0).

[0061] Among them, the computer, signal processing module, power amplifier, single-row linear speaker array itself and corresponding communication connection technology are existing technologies and will not be described in detail here.

[0062] In this embodiment, the number of speakers in each row of the linear speaker array is fixed at fourteen. The number of speakers in each row of the linear speaker array may be different in different embodiments. The number of speakers may be appropriately increased or decreased according to specific needs to achieve the best effect. When the number of speakers is large, the effect of wave field synthesis is better.

[0063] The size of the wavelength synthesis area is related to the length of the linear speaker array. The length of the linear speaker array is related to the center distance d between every two adjacent speakers. The center distance d between two adjacent speakers determines the spatial aliasing frequency of the linear speaker array. Exceeding the spatial aliasing frequency of the speaker array will affect the wavelength synthesis effect.

[0064] In the prior art, according to the wave field synthesis basis of the linear speaker array, when a single row of horizontally straight-line speaker array is used for wave field synthesis, the listener can only hear the effective wave front in the horizontal direction, and cannot accurately perform wave field synthesis in the vertical direction. The wave field synthesis is only effective on the horizontal plane containing the entire linear speaker array.

[0065] The driving step includes combining the wave field synthesis algorithm WFS and the distance-based amplitude translation algorithm DBAP to obtain the driving signal of each speaker.

[0066] Assuming that the virtual source 105, i.e., the source, moves in the y direction between the first single-row linear speaker array 103 and the second single-row linear speaker array 104, by combining the wave field synthesis algorithm WFS and the distance-based amplitude translation algorithm DBAP, a normal velocity is set at each speaker according to formula 9 and formula 10, and finite element simulation calculation is performed to obtain the corresponding simulation results. In the simulation, only the calculation formula needs to be set, so there is no need to use formula 11 and formula 12.

[0067] Formula 9 to Formula 12 combine the wave field synthesis algorithm WFS and the distance-based amplitude translation algorithm DBAP. Please refer to the following description for details of Formula 9 to Formula 12.

[0068] The application process also includes a synthesis step, which includes all speakers realizing wave field synthesis according to corresponding driving signals and expanding the effect of spatial sense in the vertical direction.

[0069] In the double-row horizontal linear speaker array wave field synthesis method proposed in the present application, it is necessary to install two rows of linear speaker arrays, a first single-row linear speaker array 103 and a second single-row linear speaker array 104, in the vertical direction. By setting the bottom speaker array, i.e., the first single-row linear speaker array 103 and the top speaker array, i.e., the second single-row linear speaker array 104, each row of speaker arrays can perform wave field synthesis on the horizontal plane of the speaker array.

[0070] like Figure 2 As shown, when the virtual source 105 moves along the vertical direction, i.e., the y-axis, between the first single-row linear speaker array 103 and the second single-row linear speaker array 104, the signal amplitude of each row of the speaker array, i.e., the speaker driving signal amplitude, is controlled according to the vertical distance between the virtual source 105 and the first single-row linear speaker array 103 or the second single-row linear speaker array 104 in the y-axis direction. The first single-row linear speaker array 103 uses Formula 9, and the second single-row linear speaker array 104 uses Formula 10 for amplitude control.

[0071] When the virtual source 105 is closer to the second single-row linear speaker array 104 in the vertical direction, combined with the distance-based amplitude panning algorithm, abbreviated as DBAP, the overall speaker driving signal amplitude gain of the second single-row linear speaker array 104 is increased, while the overall signal gain of the first single-row linear speaker array 103 is reduced, so that the overall wave field synthesis moves to the horizontal plane where the second single-row linear speaker array 104 is located, which can enhance the vertical spatial expansion.

[0072] The distance-based amplitude translation algorithm DBAP itself is a prior art and will not be described in detail here. The algorithm uses the following formulas 4, 5, 6, 7 and 8.

[0073] The gain values ​​of the two rows of linear speaker arrays will change as the distance between the y-axis coordinates of the virtual source 105 and the y-axis coordinates of the two rows of linear speaker arrays changes. The closer the virtual source 105 is to a row of speaker arrays, the higher the gain value of the corresponding row of linear speaker arrays. The gain value here is g in formula 6. i , the value is a scalar and has no direction.

[0074] The traditional single-row speaker array wave field synthesis method can only produce a synthetic sound field in the xz plane where the speaker array is located. If the virtual source moves in the y direction of the speaker array, the listener standing in front of the z-axis of the plane where the speaker array is located cannot feel the movement effect of the sound field in the y-axis direction.

[0075] By expanding a new row of linear speaker arrays, i.e., the second single-row linear speaker array 104, in the positive direction of the y-axis on the basis of a single-row speaker array, i.e., the first single-row linear speaker array 103, the wave field synthesis formulas of the first single-row linear speaker array 103 and the second single-row linear speaker array 104 are both Formula 1. Combined with the distance-based amplitude shifting algorithm DBAP, the gain value can be changed in real time according to the distance. Combining Formula 1 with the distance-based amplitude shifting algorithm DBAP, the speaker signal driving functions of the two rows of speaker arrays are Formula 11 and Formula 12 respectively.

[0076] like Figure 3 As shown in the figure, the driving function of each speaker in the speaker array can be obtained. Suppose the speakers are numbered from left to right as n=1, 2, ..., N. In the figure, r m is the location of the source, which is the virtual source 105, r n is the position of the nth speaker and r is the listening point.

[0077] Formula 1 is a formula for generating each speaker driving signal synthesized by wavelength, and each speaker driving signal is calculated according to Formula 1.

[0078] Formula 1 can be written as Q(r n ,ω)=S(ω)H n (ω), H n (ω) is written as Formula 3 for clearer expression.

[0079] The formulas used for wave field synthesis of a single-row linear loudspeaker array are: Formula 1, Formula 2, and Formula 3.

[0080] Wave field synthesis is the synthesis of the sound pressure generated by the speaker in space by generating different driving signals for each speaker in the speaker array. The speaker generates sound pressure according to the driving signal calculated by the formula input, and the corresponding sound field can be synthesized in the space. Wave field synthesis itself is the process of calculating the driving signal, and the speaker generates sound pressure according to the calculated driving signal. The sound pressure of multiple speakers produces corresponding effects in the space.

[0081] Formulas used in wave field synthesis of a double-row linear loudspeaker array: Formula 1, Formula 2, and Formula 3 are the wave field synthesis algorithm WFS; Formula 4, Formula 5, Formula 6, Formula 7, and Formula 8 are the distance-based amplitude translation algorithm DBAP.

[0082] Wave field synthesis is actually the calculation of the speaker driving signal. The speaker generates sound pressure according to the calculated driving signal. The sound pressure generated by each speaker is heard in the space as the synthesized sound pressure. You only need to calculate the driving signal according to the formula.

[0083] Formula 9, Formula 10, Formula 11 and Formula 12 are expression formulas for combining the wave field synthesis algorithm WFS and the amplitude translation algorithm.

[0084] The synthesis step is that all speakers generate specific driving signals to complete the synthesis; Formula 9 to Formula 12 are the combination of the wave field synthesis algorithm WFS and the distance-based amplitude translation algorithm DBAP, Formula 1 to Formula 3 are the formulas required by the wave field synthesis algorithm WFS, Formula 4 to Formula 8 are the formulas required by the distance-based amplitude translation algorithm DBAP, and the innovative method of this application is Formula 9 to Formula 12, which is the formula that combines the wave field synthesis algorithm WFS and the distance-based amplitude translation algorithm DBAP. Formula 1 to Formula 12 are required, Formula 1 to Formula 8 are the basis, and Formula 9 to Formula 12 are innovative combinations.

[0085] The driving function of the nth speaker can be expressed as Equation 1:

[0086] Formula 1: ;

[0087] In formula 1, Q(r n ,ω) is the frequency domain of the driving signal of each speaker, ω is the angular frequency, k is the wave number, S(ω) is the original driving signal spectrum, unit is dB; G n (θn, ω) is the directivity function of the nth loudspeaker, z0 is the coordinate value of the source in the z direction, z1 is the coordinate value of the loudspeaker in the z direction, and z is the coordinate value of the listening point in the z direction.

[0088] The nth loudspeaker transfer function can be expressed as Equation 2:

[0089] Formula 2: ;

[0090] In formula 2, H n (ω) is the frequency domain expression.

[0091] Here formula 1 is too long, use H n (ω) is used to make the following long string equivalent, which is beneficial for the subsequent calculation. n (ω) is the core of the WFS formula calculation of the wave field synthesis algorithm. The original signal is processed by calculation and the processed driving signal is output.

[0092] Formula 2 can be rewritten as Formula 3:

[0093] Formula 3: ;

[0094] In formula 3, |A n (ω) | is H in Formula 2 n The magnitude of (ω), φ n (ω) is H n The phase of (ω).

[0095] In engineering, Formula 3 is a frequency domain representation. In Formula 2, H n (ω) is a frequency domain expression, so Formula 2 can be written as the general frequency domain expression of Formula 3, which is an expression of amplitude and phase. |An| is the amplitude degree.

[0096] Formula 1 is a calculation formula for the wave field synthesis driving signal, and Formulas 2 and 3 are auxiliary.

[0097] The above are the relevant formulas for wave field synthesis of a single-row horizontal linear speaker array. When a double-row linear speaker array is used for wave field synthesis, the wave field synthesis formulas used by the two rows of speaker arrays are the same.

[0098] like Figure 2 As shown, the y-direction coordinate value of the first single-row linear speaker array 103 is 0, and the y-direction coordinate value of the second single-row linear speaker array 104 is H. Assuming there is a virtual source 105, the y-direction coordinate value of the virtual source 105 is ym. The vertical distances between the virtual source 105 and the first single-row linear speaker array 103 and the second single-row linear speaker array 104 in the y-axis direction are d1 and d2 respectively:

[0099] Formula 4: ;

[0100] In formula 4, d1 is the vertical distance between the virtual source and the first single-row linear speaker array 103 in the y-axis direction; m is the coordinate value of the virtual source in the y direction.

[0101] Formula 5: ;

[0102] In Formula 5, d2 is the vertical distance between the virtual source and the second single-row linear speaker array 104 in the y-axis direction, and H is the vertical center distance between the first single-row linear speaker array 103 and the second single-row linear speaker array 104 .

[0103] According to the distance-based amplitude panning algorithm DBAP, in the present application, each row of the linear speaker array has the same amplitude panning gain.

[0104] The translation mentioned here means that one row of speaker arrays is equivalent to one point, and two rows of speaker arrays are equivalent to two points, and the DBAP algorithm is applied to these two points.

[0105] Assuming that the amplitude translation gain of each speaker in the first single-row linear speaker array 103 is g1, and the amplitude translation gain of each speaker in the second single-row linear speaker array 104 is g2, the gain formula can be expressed as Formula 6.

[0106] Formula 6: ;

[0107] In formula 6, g i is the gain value of the driving signal of the row of speaker arrays closer to the virtual source 105, which is a scalar without direction. i is the serial number of the single-row linear speaker array, and l is the normalization coefficient, which depends on the vertical distance between the virtual source 105 and the two rows of speaker arrays.

[0108] For two rows of speaker arrays, there must be g1 and g2, but each row of speaker array corresponds to a different g value.

[0109] The calculation formulas of l and a can be expressed as:

[0110] Formula 7: ;

[0111] Formula 8: ;

[0112] In formula 8, a represents the coefficient of R attenuation in decibels for every doubling of the distance.

[0113] By combining the wave field synthesis algorithm WFS and the distance-based amplitude translation algorithm DBAP, the transfer functions of the first single-row linear speaker array 103 and the second single-row linear speaker array 104 are obtained as follows:

[0114] Formula 9: ;

[0115] In formula 9, H 1n (ω) is the frequency domain expression of the first single-row linear speaker array 103, and H in Formula 2 and Formula 3 n (ω) has the same function as auxiliary; g1 is the gain value of the virtual source 105 from the first single-row linear speaker array 103; |A 1n (ω) | is H 1n (ω); 1n is the speaker identifier, where 1 represents the first row and n represents the nth speaker; ω is the circular frequency, j is the imaginary unit, φ n is the phase angle of the signal of the nth loudspeaker.

[0116] Formula 10: ;

[0117] In formula 10, H 2n(ω) is the frequency domain expression of the second single-row linear speaker array 104 loudspeaker, and H in Formula 2 and Formula 3 n (ω) has the same function as auxiliary; g2 is the gain value of the virtual source 105 from the second single-row linear speaker array 104; |A 2n (ω)| is H 2n (ω), 2n is the speaker identifier, where 2 represents the second row, n represents the nth speaker, ω is the circular frequency, j is the imaginary unit, φ n is the phase angle of the signal of the nth loudspeaker.

[0118] The driving functions of each speaker in the first single-row linear speaker array 103 and the second single-row linear speaker array 104 are respectively:

[0119] Formula 11: ;

[0120] In formula 11, Q1(r n ,ω) is the frequency domain expression of the driving signal of each speaker in the first single-row linear speaker array 103; S(ω) is the original driving signal spectrum, in dB; r n is the position coordinate of the nth speaker in polar coordinates.

[0121] Formula 12: ;

[0122] In formula 12, Q2(r n ,ω) is the frequency domain expression of the driving signal of each loudspeaker in the second single-row linear loudspeaker array 104.

[0123] Among them, the wave field synthesis algorithm WFS and the distance-based amplitude migration algorithm DBAP are both existing technologies and will not be described in detail here.

[0124] In order to verify the spatial expansion effect of the proposed double-row linear speaker array wave field synthesis method in the vertical direction, the generated sound field was simulated and analyzed using COMSOL finite element simulation software.

[0125] like Figure 2As shown, each row of linear speaker arrays includes 14 speakers, and the horizontal spacing between two speakers is 80mm. The vertical center distance H between the first single-row linear speaker array 103 and the second single-row linear speaker array 104 is set to 500mm. The y-direction coordinate value of the first single-row linear speaker array 103 is 0, and the y-direction coordinate value of the second single-row linear speaker array 104 is 500mm. Assuming that the virtual source 105 moves in the y direction between the first single-row linear speaker array 103 and the second single-row linear speaker array 104, by combining the wave field synthesis algorithm WFS and the distance-based amplitude translation algorithm DBAP, a normal velocity is set at each speaker according to Formula 9 and Formula 10, and finite element simulation calculations are performed to obtain the corresponding simulation results. In the simulation, you only need to set the calculation formula, so there is no need to use Formula 11 and Formula 12.

[0126] like Figure 5 to Figure 7 As shown, simulation software is used to simulate a virtual source 105 located between a first single-row linear speaker array 103 and a second single-row linear speaker array 104. The sound pressure changes generated by the two rows of speaker arrays during the movement in the positive direction of the y-axis. It can be seen that during the movement of the virtual source 105 in the positive direction of the y-axis, the position of the sound field synthesis also moves in the positive direction of the y-axis, which means that the overall wave field synthesis moves in the vertical direction. The sound field synthesis can bring out the movement effect of the sound in the vertical direction in the auditory sense of movement in the vertical direction. Therefore, the above-mentioned double-row linear speaker wave field synthesis algorithm can achieve the spatial expansion effect in the vertical direction.

[0127] Figure 5 , Figure 6 and Figure 7 These are the different sound pressure distribution diagrams of the virtual source 105 moving in the positive direction of the y-axis, where y m is the y direction coordinate of the virtual source 105.

[0128] like Figure 5 As shown, at this time, the virtual source 105 is closer to the first single-row linear speaker array 103 in the y direction. At this time, the sound pressure amplitude generated by the first single-row linear speaker array 103 is 7.1Pa, and the sound pressure amplitude generated by the second single-row linear speaker array 104 is 0.78Pa, so the first single-row linear speaker array 103 generates a larger sound pressure.

[0129] Sound pressure can be positive or negative. The above-mentioned sound pressure amplitude, the amplitude is the magnitude, and we only focus on the absolute value.

[0130] like Figure 5 As shown, the left edge of the first single-row linear speaker array 103 is very dark in color, and the sound pressure amplitude can reach 7.1 Pa. The figures generated by the comsol simulation are all values ​​existing in the sound pressure distribution.

[0131] The above formulas are all related to the driving signal. Sound pressure refers to the sound pressure generated by the sound emitted by the speaker, and does not involve formulas related to sound pressure.

[0132] like Figure 1 As shown, if a listener is arranged as shown in the figure, the listener can hear the sound near the plane where the first single-row linear speaker array 103 is located.

[0133] like Figure 6 As shown, the virtual source 105 moves between the first single-row linear speaker array 103 and the second single-row linear speaker array 104. At this time, the sound pressure amplitude generated by the first single-row linear speaker array 103 is 3.65Pa, which is equivalent to the sound pressure amplitude generated by the second single-row linear speaker array 104 being 3.71Pa. It can be seen from the simulated sound pressure that the sound pressure is distributed between the first single-row linear speaker array 103 and the second single-row linear speaker array 104.

[0134] like Figure 7 As shown, the virtual source 105 moves to the vicinity of the second single-row linear speaker array 104. At this time, the virtual source 105 is closer to the second single-row linear speaker array 104 in the y direction. At this time, the first single-row linear speaker array 103 produces a sound pressure amplitude of 0.84Pa and the second single-row linear speaker array 104 produces a sound pressure amplitude of 4.06Pa, which is larger, while the first single-row linear speaker array 103 produces a smaller sound pressure.

[0135] like Figure 1 As shown, if a listener is arranged as shown in the figure, the listener can hear the sound near the plane where the second single-row linear speaker array 104 is located.

[0136] The synthesis moves in the vertical direction as the virtual source 105 moves in the positive direction of the y-axis. Figure 1 The position shown in the figure is used for subjective listening judgment. From the sense of hearing, it can be heard that the maximum sound pressure moves in the positive direction of the y-axis. This sense of movement in the y-direction is the expansion effect of the proposed double-row speaker array wave field synthesis in the y-direction. This is an effect that cannot be achieved by the single-row speaker array wave field synthesis.

[0137] The vertical movement effect of sound is an auditory performance. Its function is that when the virtual source moves in the y-axis direction of the linear speaker, the sound can achieve the auditory effect of the linear speaker array moving in the y-axis direction.

[0138] Compared with the wavelength synthesis method of a single-row linear speaker array, the wavelength synthesis of a double-row linear speaker array can achieve spatial expansion in the y-axis direction of the linear speaker array. When the virtual source moves in the positive direction of the y-axis of the two-row linear speaker array, the sound field synthesis will show movement in the positive direction of the y-axis. Compared with the wavelength synthesis method of a single-row linear speaker array, the wavelength synthesis of a double-row linear speaker array can achieve spatial expansion in the y-axis direction, and the sound field movement in the y-axis direction will be felt.

[0139] This application proposes a wave field synthesis method for a double-row horizontal linear speaker array. Compared with the wave field synthesis method for a single-row horizontal linear speaker array, the advantages of this method are mainly as follows:

[0140] (1) The wave field synthesis method of the double-row horizontal linear speaker array can also show good spatiality in the vertical direction, while the wave field synthesis of the single-row horizontal linear speaker array can only achieve good wave field synthesis effects in the plane where the array is located.

[0141] (2) In order to achieve the vertical wave field synthesis effect, the method of expanding the linear speaker array in the vertical direction can greatly reduce the number of speakers and the cost, and the implementation method is simple and easy to implement.

[0142] Embodiment 2:

[0143] The present invention discloses a double-row linear speaker array driving method. Embodiment 2 is different from Embodiment 1 in that the double-row linear speaker array in Embodiment 1 is rotated 90 degrees with the z-axis as the axis to become a double-row longitudinal linear speaker array. The similarities are not repeated here.

[0144] In Example 1, the double-row horizontal linear speaker array is a speaker array designed for a specific stage scene. If it is rotated to become a double-row vertical linear speaker array, the synthesis method steps remain unchanged, but the produced effect will be different. At this time, there are more speakers in the y direction and fewer speakers in the x direction. The produced effect is that the sound field movement effect in the y direction is more obvious, while the sound field movement effect in the x direction is not obvious.

[0145] As mentioned above, the sound field movement effect has a clear relationship with the number of speakers. The more speakers there are, the better the wave field synthesis effect is. Assuming that the more speakers are distributed in the x direction, the more obvious the sound field movement effect is when the virtual source moves in the x direction; the more speakers are distributed in the y direction, the more obvious the sound field movement effect is when the source moves in the y direction.

Claims

1. A double-row linear speaker array driving method, based on a computer, a signal processing module, a power amplifier and a speaker array electrically connected in sequence, characterized in that: The speaker array is a double-row linear speaker array, the double-row linear speaker array comprising two single-row linear speaker arrays with the same structure, namely a first single-row linear speaker array (103) and a second single-row linear speaker array (104), the first single-row linear speaker array (103) and the second single-row linear speaker array (104) being arranged in parallel and aligned; The method comprises a driving step, wherein the driving step comprises combining a wave field synthesis algorithm WFS and a distance-based amplitude translation algorithm DBAP, obtaining a frequency domain of a first single-row linear speaker array (103) according to formula 9, obtaining a frequency domain of a second single-row linear speaker array (104) according to formula 10, and then calculating a driving signal of each speaker; Formula 9: ; In formula 9, H 1n (ω) is the frequency domain expression of the first single-row linear loudspeaker array (103); g1 is the gain value of the source distance from the first single-row linear loudspeaker array (103); |A 1n (ω) | is H 1n (ω) amplitude; 1n is the speaker identifier, where 1 represents the first row and n represents the nth speaker; ω is the circular frequency, j is the imaginary unit, φ n is the phase angle of the signal of the nth loudspeaker; Formula 10: ; In formula 10, H 2n (ω) is a frequency domain expression of the second single-row linear loudspeaker array (104); g2 is a gain value of the source distance from the second single-row linear loudspeaker array (104); |A 2n (ω)| is H 2n (ω) amplitude; 2n is the speaker identifier, where 2 represents the second row, n represents the nth speaker, ω is the circular frequency, j is the imaginary unit, φ n is the phase angle of the signal of the nth loudspeaker; In the driving step, the driving functions of each loudspeaker in the first single-row linear loudspeaker array (103) and the second single-row linear loudspeaker array (104) are respectively: Formula 11: ; In formula 11, Q1(r n ,ω) is the frequency domain expression of the driving signal of each loudspeaker in the first single-row linear loudspeaker array (103), S(ω) is the original driving signal spectrum, in dB; r n is the position coordinate of the nth loudspeaker in polar coordinates; Formula 12: ; In formula 12, Q2(r n ,ω) is a frequency domain expression of a driving signal of each loudspeaker in the second single-row linear loudspeaker array (104).

2. A double-row linear speaker array driving method according to claim 1, characterized in that: The second single-row linear speaker array (104) is located above the first single-row linear speaker array (103), forming a double-row lateral linear speaker array.

3. A double-row linear speaker array driving method according to claim 1, characterized in that: The second single-row linear speaker array (104) is located on one side of the first single-row linear speaker array (103), forming a double-row longitudinal linear speaker array.

4. A double-row linear speaker array driving method according to claim 1, characterized in that: The first single-row linear speaker array (103) and the second single-row linear speaker array (104) respectively comprise fourteen speakers, and the fourteen speakers are sequentially arranged in a transverse straight line to form a single-row linear speaker array.

5. The double-row linear speaker array driving method according to claim 1, characterized in that: The method also includes a synthesis step, wherein all loudspeakers realize wave field synthesis according to corresponding driving signals and expand the spatial sense in the vertical direction.

6. A double-row linear speaker array driving method according to claim 1, characterized in that: In the driving step, Formula 4: ; In formula 4, d1 is the vertical distance between the source and the first single-row linear speaker array (103) in the y-axis direction; y m is the coordinate value of the source in the y direction; Formula 5: ; In formula 5, d2 is the vertical distance between the source and the second single-row linear speaker array (104) in the y-axis direction, and H is the vertical center distance between the first single-row linear speaker array (103) and the second single-row linear speaker array (104); Assuming that the amplitude translation gain of each loudspeaker in the first single-row linear loudspeaker array (103) is g1, and the amplitude translation gain of each loudspeaker in the second single-row linear loudspeaker array (104) is g2, the gain formula is expressed as Formula 6; Formula 6: ; In formula 6, g i is the gain value of the driving signal of the row of speaker arrays closer to the source in the two rows of speaker arrays. The gain value is a scalar and has no direction. i is the serial number of the single-row linear speaker array, and l is the normalization coefficient, which depends on the vertical distance between the source and the two rows of speaker arrays. The calculation formulas of l and a are expressed as: Formula 7: ; Formula 8: ; In formula 8, a represents the coefficient of attenuation R in decibels for every doubling of the distance.

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