Screen reflection type sound production system and method

Abstract

The invention discloses a screen reflection type sound production system and method, and the method comprises the steps: carrying out the frequency division of an input signal through a signal processing module, and carrying out the high-frequency signal delay compensation and low-frequency directional control, so as to obtain n paths of high-frequency outputs and N paths of low-frequency outputs; after the power amplifier amplifies the power of the signal, the signal is fed to n high-frequency loudspeakers and N low-frequency loudspeakers of the transducer device; the transducer device radiates the high-frequency outputs and the N low-frequency outputs received by the n high-frequency loudspeakers and the N low-frequency loudspeakers to the reflective screen. According to the invention, through the delay compensation of the high-frequency signal and the directivity control of the low-frequency band, it can be ensured that the full frequency band is reflected by the reflection screen and then radiated to the audience, additional delay compensation does not need to be carried out on the low-frequency loudspeaker, the number of needed loudspeakers is reduced, and the cost is remarkably reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of loudspeakers and relates to a screen reflection sound generation system and method. Background Art

[0002] New luminous screen technologies such as LED and OLED have gradually matured and have been widely used in applications such as cinemas and conferences. However, sound cannot be projected through the luminous screen, which makes the method of using speakers behind the screen to achieve the center channel sound in traditional cinemas invalid. In this regard, the existing technology proposes the following solutions:

[0003] (1) The full bandwidth audio input signal is divided into high frequency and low frequency components. The high frequency speaker is located in front of the acoustic reflective image screen and tilted toward the image screen so that the sound emitted by the high frequency speaker in response to the high audio signal input is reflected from the image screen. The low frequency speaker is located at or around the acoustic reflective image screen. In this technology, the low frequency speaker needs to be delayed compensated so that the direct sound from the low frequency speaker arriving at the audience space is aligned in time with the sound from the high frequency speaker reflected from the display screen. However, the delay compensation required by the low frequency speaker is different for different audience positions, so it is impossible to achieve delay alignment of high frequency and low frequency in the entire audience space, resulting in sound distortion, affecting the spatial positioning effect and timbre naturalness of the sound.

[0004] (2) A high-frequency speaker with strong directivity and a low-frequency speaker with wide directivity are integrated into one box, where the high-frequency speaker faces the screen, and the audio signal processing unit delays the low-frequency speaker based on the detection information related to the distance from the screen surface, so that the low-frequency sound reaches the audience slightly later than the high-frequency sound. This technology uses the Haas effect to localize the sound image perceived by the audience to the reflected high-frequency sound that arrives first. However, this causes the high-frequency sound and the low-frequency sound to be misaligned at each listening position, that is, there is a delay between the high-frequency sound and the low-frequency sound, resulting in sound distortion, affecting the spatial positioning effect of the sound and the naturalness of the timbre.

[0005] (3) Arrange the two-dimensional acoustic transducers based on the principle of wave field synthesis so that the wavefronts they emit can be associated with the sound source optically displayed in the corresponding area of ​​the same screen after being reflected by the screen. Compared with the first two solutions, there is no frequency division processing, and the designed two-dimensional array transmits full-band signals. However, according to the principle of wave field synthesis, to ensure the playback effect of the low frequency band, the array needs to have a large enough volume, and to ensure the playback effect of the high frequency band, the intervals between different units in the array need to be small enough. Therefore, a huge number of speakers are required, which is expensive. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides a screen reflection sound generation system and method.

[0007] The present invention adopts the following technical solution.

[0008] A first aspect of the present invention provides a screen reflection sound system, comprising a signal processing module, a power amplifier and a transducer device; wherein the transducer device comprises n high-frequency speakers and N low-frequency speakers, wherein n is greater than or equal to 1, and N is greater than or equal to 2;

[0009] The signal processing module is used to perform high-frequency signal delay compensation and low-frequency directivity control on the input signal after frequency division, so as to obtain n-channel high-frequency output and N-channel low-frequency output;

[0010] The power amplifier is used to amplify the power of the n high-frequency outputs and the N low-frequency outputs of the signal processing module and feed them to the n high-frequency speakers and the N low-frequency speakers in the transducer device respectively;

[0011] The transducer device is arranged opposite to the reflective surface, and the reflective surface is arranged opposite to the audience area;

[0012] The transducer device is used to radiate the high-frequency output and the low-frequency output received by the high-frequency speaker and the low-frequency speaker to the reflecting surface.

[0013] Preferably, the transducer device is arranged above the center of the audience area, above the left side of the audience area, above the right side of the audience area, or below the audience area.

[0014] Preferably, in the transducer device, the high frequency speaker is located in front of the box, facing the reflecting surface;

[0015] Among the N low-frequency speakers, at least one woofer is arranged in front of the box, facing the reflecting surface, and at least one woofer is arranged on the side, back or bottom of the box.

[0016] Preferably, the transducer device further comprises an inverted hole for expanding low-frequency sound waves.

[0017] Preferably, the number of the transducer devices is K, and the K transducer devices are combined to enhance the directivity control effect and increase the maximum sound pressure level, and the combination form is that the K transducer devices are connected up and down and arranged in a linear or J-shaped transducer device array, wherein each transducer device can perform relative pitch angle adjustment.

[0018] Preferably, the signal processing module includes a frequency divider, a high-frequency branch and a low-frequency branch;

[0019] The frequency divider is used to perform frequency division, divide the input signal into a low-frequency signal and a high-frequency signal, and transmit the signals to the low-frequency branch and the high-frequency branch respectively;

[0020] The high-frequency branch is used to perform delay compensation, phase correction and amplitude correction on the high-frequency signal to obtain n-channel high-frequency outputs;

[0021] The low-frequency branch is used to perform phase correction, amplitude correction and N-way parallel beam filtering on the low-frequency signal based on a low-frequency band directivity control algorithm to obtain N-way low-frequency outputs.

[0022] Preferably, the frequency divider uses a frequency division frequency f between the low-frequency signal and the high-frequency signal. c satisfy:

[0023] Where c is the speed of sound and d is the minimum distance between different low-frequency speakers.

[0024] Preferably, the high-frequency branch comprises a delay module, a first phase correction module and a first amplitude correction module connected in sequence, which respectively perform delay compensation, phase correction and amplitude correction on the high-frequency signal;

[0025] The low-frequency branch includes a second phase correction module, a second amplitude correction module and N beam filters connected in sequence, which respectively perform phase correction, amplitude correction and N-way parallel beam filtering based on a low-frequency directivity control algorithm on the low-frequency signal.

[0026] Preferably, the compensation time τ of the delay compensation is t2-t1, wherein t1 is the arrival time of the sound wave from the low frequency speaker array to the measuring point at a distance R from the transducer device, and t2 is the arrival time of the sound wave from the high frequency speaker to the measuring point at a distance R from the transducer device.

[0027] Preferably, the phase correction and amplitude correction methods of the low-frequency branch are the same as those of the high-frequency branch, and the phase correction and amplitude correction methods are:

[0028] Select m measurement points distributed in the directivity rangeΩ={Ω1,Ω2,…,Ω m}, measure the response A(ω,Ω from the transducer device to each measurement point in the anechoic chamber i ), where the magnitude represents the magnitude response and the phase represents the phase response;

[0029] Average the responses of the m measurement points to obtain the mean phase amplitude response

[0031] Calculate the mean phase magnitude response The difference between the target frequency response D(ω) The magnitude and phase of P(ω) are used as the responses of the amplitude correction and phase correction filters.

[0032] Preferably, the N beam filters determine the filter coefficient of each beam filter based on a low-frequency band directivity control algorithm, as follows:

[0033] By solving the following objective function, the complex weight coefficients of the beam filters corresponding to each low-frequency speaker are obtained:

[0034] min‖h(ω,X)‖1(2)

[0035] st ‖G(ω,Φ,X)h(ω,X)-d(ω,Φ)‖2≤∈ (3)

[0036] Among them, ∈ is a parameter used to control the accuracy and robustness of the beam;

[0037] ‖·‖1, ‖·‖2 are 1-norm and 2-norm;

[0038] The value range of ω is 0~2πf c Between c is the crossover frequency;

[0039] d(ω,Φ) is the directivity target of the path from the center of the low-frequency speaker array to the corresponding spatial angle Φ reflected by the screen to the audience area at the angular frequency ω;

[0040] G(ω,Φ,X) is the transfer function matrix from each low frequency loudspeaker to each control point. The i-th row and j-th column element of G(ω,Φ,X) represents the transfer function from the j-th low frequency loudspeaker to the i-th control point.

[0041] h(ω,X)=[h(ω,X1),h(ω,X2),…,h(ω,X N )] T is the complex weight coefficient of the N beam filters at the angular frequency ω, where h(ω,X i ) represents the i The complex weight coefficient of the beam filter corresponding to the low-frequency speaker, that is, the filter coefficient.

[0042] Preferably, Φ={Φ1,Φ2,…,Φ M} are the spatial angles of M control points distributed on a sphere with a distance R from the center of the low frequency speaker array;

[0043] d(Φ)=[d(Φ1),d(Φ2),…,d(Φ M )] T , if the space angle Φ iThe corresponding path reflected from the screen to the audience area is r i , then d(Φ i )=r i ·R, if the space angle Φ i The radiated sound is directly transmitted to the audience area, and there is no path reflected from the screen to the audience area. Then d(Φ i )=0.

[0044] A second aspect of the present invention provides a screen reflection type sound-speaking method, using the system according to any one of claims 1 to 12, characterized in that the method comprises:

[0045] The signal processing module divides the input signal and performs high-frequency signal delay compensation and low-frequency directivity control to obtain n-channel high-frequency output and N-channel low-frequency output;

[0046] The power amplifier amplifies the n high-frequency outputs and the N low-frequency outputs of the signal processing module and feeds them to the n high-frequency loudspeakers and the N low-frequency loudspeakers of the transducer device respectively;

[0047] The transducer device radiates the n-channel high-frequency outputs and the N-channel low-frequency outputs received by the n high-frequency loudspeakers and the N low-frequency loudspeakers to the reflecting surface.

[0048] A third aspect of the present invention provides a terminal, comprising a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method.

[0049] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when executed by a processor.

[0050] Compared with the prior art, the beneficial effects of the present invention include at least:

[0051] The sound generation system of the present invention comprises a transducer device and a signal processing module matched therewith for processing audio signals, wherein the transducer device integrates a high-frequency speaker and a group of low-frequency speakers into one body and places them in front of a reflective screen, and the signal processing module uses beamforming and other related algorithms to precisely control the directivity of a group of low-frequency speakers so that their radiation characteristics achieve similar effects to those of high-frequency speakers, thereby ensuring that the direct sound from the speakers will not diffuse to the audience area, but will be radiated to the audience through the reflection of the reflective screen in the full frequency band.

[0052] The present invention integrates the low-frequency speaker and the high-frequency speaker into one, so that the acoustic center of the sound wave radiated by the low-frequency speaker array and the acoustic center of the sound wave radiated by the high-frequency speaker can be approximately in the same spatial position, and the travel path of the sound emitted by the two to any audience point is basically the same, and there is no need to perform additional delay compensation on the low-frequency speaker. At the same time, each frequency band of the sound can arrive at the audience synchronously, thereby ensuring the spatial precise positioning effect of the sound and better sound quality performance.

[0053] The high-frequency speaker part of the present invention uses a transducer device with strong directivity such as a horn, and the low-frequency branch determines the filter coefficient of each beam filter through a low-frequency band directivity control algorithm to implement low-frequency branch beam control. Specifically, by minimizing the 1-norm of the complex weight coefficients of N beam filters at the angular frequency ω, it can ensure that the target response is as close as possible while using fewer low-frequency speakers, and the number of low-frequency speakers required is small, which significantly reduces the cost.

[0054] Compared with the commonly used beam control method in the prior art, the low-frequency band directivity control algorithm of the present invention distributes the control points in three-dimensional space, and the directivity target is calculated according to the reflection path, which can effectively control the beam effect in an environment taking screen reflection into account. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is the typical structure of the system;

[0056] Figure 2 This is a vertical plane arrangement example 1 of the transducer assembly device of the present invention;

[0057] Figure 3 This is a vertical plane arrangement example 2 of the transducer assembly device of the present invention;

[0058] Figure 4 is an exemplary horizontal plane arrangement of a transducer assembly device according to the present invention;

[0059] Figure 5 is the transducer device example 1 of the present invention;

[0060] Figure 6 is the transducer device example 2 of the present invention;

[0061] Figure 7 is the transducer device example 3 of the present invention;

[0062] Figure 8 is a signal flow chart of a signal processing module of the present invention;

[0063] The accompanying drawings are marked as follows: 1-signal processing module, 2-transducer device, 3-reflecting surface, 4-audience area; 101-divider, 102-delay module, 103-first phase correction module, 104-first amplitude correction module, 105-second phase correction module, 106-second amplitude correction module, 107-beam filter; 201-low frequency speaker, 202-high frequency speaker, 203-installation position of the inverted hole; 201L-left position, 201R-right position, 201B-back position, 201U-bottom position; 2L-left side of the audience area, 2R-right side of the audience area, 2U-below the audience area; 2P-equivalent speaker. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0065] Embodiment 1 of the present invention provides a screen reflection sound generation system, such as Figure 1 As shown, it includes a signal processing module 1, a transducer device 2 and a power amplifier; wherein the transducer device 2 includes n high-frequency speakers 202 and N low-frequency speakers 201 integrated in a box; the signal processing module 1 and the power amplifier can be integrated with or separated from the speaker group (transducer device 2); wherein n is greater than or equal to 1, and N is greater than or equal to 2.

[0066] The acoustic center of the sound waves radiated by the array of the low-frequency loudspeakers 201 and the acoustic center of the sound waves radiated by the array of the high-frequency loudspeakers are approximately in the same spatial position;

[0067] The signal processing module 1 is used to perform high-frequency signal delay compensation and low-frequency directivity control on the input signal after frequency division, so as to obtain n-channel high-frequency output and N-channel low-frequency output;

[0068] The power amplifier is used to amplify the power of the n high-frequency outputs and the N low-frequency outputs of the signal processing module 1 and feed them to the n high-frequency speakers 202 and the N low-frequency speakers 201 of the transducer device 2 respectively;

[0069] The transducer device 2 is arranged opposite to the reflective surface 3, and the reflective surface 3 is arranged opposite to the audience area 4. The reflective surface 3 includes but is not limited to an acoustic reflective interface such as a reflective screen, a projection wall or a mirror or glass in front of the screen;

[0070] The transducer device 2 is used to radiate the n high-frequency outputs and N low-frequency outputs received by the n high-frequency speakers 202 and the N low-frequency speakers 201 to the reflecting surface 3, and to control the n high-frequency outputs and N low-frequency outputs radiated to the reflecting surface 3.

[0071] The present invention achieves the matching of the directivity of the high-frequency working frequency band and the directivity of the low-frequency working frequency band of the loudspeaker through the above-mentioned high-frequency signal delay compensation and low-frequency band directivity control, thereby realizing the directivity control of the full-band of the loudspeaker, so that the full-band sound of the loudspeaker reflected by the reflecting surface 3 covers the audience area 4, while the directly radiated sound will not spread into the audience area 4.

[0072] Figure 2 and Figure 3 2 is an exemplary vertical plane arrangement of the device of the present invention. The present invention places the integrated device of the high-frequency speaker 202 and the low-frequency speaker 201 - the transducer device 2 in front of the reflective surface 3, and controls the signal fed to a group of low-frequency speakers 201 so that the directivity in the low-frequency working frequency band matches the directivity of the high-frequency speaker 202, thereby achieving full-band directivity control, and overall meeting the following requirements: the sound of the full-band speaker reflected by the image screen covers the audience area 4, while the sound directly radiated does not spread into the audience area 4. Figure 2 and Figure 3 At the same time, it is demonstrated how the broadband sound radiated by the system of the present invention is reflected to the audience through the reflective surface 3 to produce an effect equivalent to that of an equivalent loudspeaker 2P at the same height and distance behind the reflective surface 3.

[0073] Figure 4 2 is an exemplary horizontal plane arrangement of the device according to the present invention. As can be seen from the figure, the transducer device 2 has a wide directivity in the horizontal direction, so that the reflected sound can cover the entire audience area 4. In addition to being placed above the center of the audience area 4, the device of the present invention can also be placed above the left side 2L of the audience area or above the right side 2R of the audience area or other places such as Figure 2 2U below the audience area in the image, or any other location that can reach the above target considerations.

[0074] Figure 5 2 is a schematic example of a transducer device of the present invention, wherein the transducer device 2 comprises a high-frequency speaker 202 and a low-frequency speaker 201. The high-frequency speaker 202 is located in front of the device (when n is greater than 1, multiple high-frequency speakers 202 are located in front of the box), facing the reflective surface 3, and has strong directivity. There are two or more low-frequency speakers 201, among which at least one low-frequency speaker 201 is located in front of the device (facing the reflective surface 3), and at least one low-frequency speaker is located on the side (left or right), or on the back, or on the bottom of the device.

[0075] The transducer device 2 also includes an inverted hole for expanding low-frequency sound waves. The installation position 203 of the inverted hole can also be appropriately selected, such as Figure 5 shown.

[0076] There are many considerations for the shape of the device, the number of speakers, the arrangement of speakers, the number and position of the inverted holes, etc. Corresponding to various speaker arrangements, the transducer device 2 can also be composed of a plurality of separate boxes.

[0077] The preferred distribution is:

[0078] The high frequency speakers 202 are located in front of the device, and the inverted holes 203 are located on the left and right sides of the device. To meet the three-dimensional directivity control, the low frequency speakers are typically located in the front, left 201L, right 201R, back 201B and bottom 201U of the device.

[0079] Further preferably, according to the array directivity control performance requirements of the application scenario, the low-frequency speakers can be appropriately reduced to reduce weight and reduce costs, and only one or two of the three groups of positions on the left and right sides, the rear side and the bottom can be set. For example, only speakers distributed on the left and right sides (left position 201L, right position 201R) and the bottom (bottom position 201U) are set without setting a rear side (rear position 201B) speaker.

[0080] Another preferred embodiment of the present invention is:

[0081] Multiple transducer devices 2 are combined to further enhance the directivity control effect and increase the maximum sound pressure level. The combination form is that multiple transducer devices 2 are connected up and down, such as Figure 6 shown.

[0082] When multiple transducer devices 2 are combined, each transducer device 2 can be adjusted in relative pitch angle. There are many ways to arrange the transducer devices 2. The preferred way is as follows: Figure 7 As shown, the arrangement is linear or J-shaped to better achieve directivity control effect.

[0083] Figure 8 It is a signal flow chart of the signal processing module of the present invention. After the input signal passes through the signal processing module 1, it passes through the power amplifier and is fed to each speaker respectively. The signal processing module 1 includes a frequency divider 101, a high frequency branch and a low frequency branch;

[0084] The crossover 101 is used to perform frequency division, dividing the input signal into a low-frequency signal and a high-frequency signal, and transmitting them to the low-frequency branch and the high-frequency branch respectively; the crossover frequency (the frequency intersection point of the high-frequency signal and the low-frequency signal) is determined by the specific device properties (the directivity control frequency range of the high-frequency horn, the number and arrangement of the low-frequency speakers 201, etc.), and for a typical transducer configuration, the crossover frequency is generally in the range of 300Hz to 4000Hz.

[0085] For low-frequency speaker arrays, in order to achieve effective control of their directivity within the playback frequency, the unit spacing d must be less than half of the wavelength corresponding to the highest control frequency, that is,

[0086]

[0087] Where c is the speed of sound, f c is the crossover frequency, d is the minimum interval between different low-frequency loudspeakers 201, therefore, the crossover frequency range should be:

[0088]

[0089] Let X = {X1, X2, …, X N} is the coordinate set of each low frequency loudspeaker 201, then d=

[0090] min{‖X i -X j ‖,i≠j}, which is the minimum interval between different low-frequency speakers.

[0091] From a physical structure perspective, d should be larger than the diameter of the low-frequency speaker and smaller than the maximum size of the device. For a low-frequency speaker with a diameter of no less than 50 mm, the lower limit of d is 50 mm; if the maximum size of the transducer device is less than 0.6 m, the upper limit of d is 0.6 m. Therefore, the typical crossover frequency f c Set between 300Hz and 4000Hz.

[0092] The frequency division mode of the frequency divider 101 is not limited to the binary frequency division mode mentioned above, and can also perform q frequency division, where q can be greater than or equal to 3. For the q frequency division situation, according to formula (1), the beam division frequency point can be defined as: Below f cb The frequency band adopts the low-frequency branch solution in the above two-way frequency division solution, which is higher than f cb The frequency band adopts the high-frequency branch solution in the above-mentioned two-way frequency division solution.

[0093] The high-frequency branch includes a delay module 102, a first phase correction module 103 and a first amplitude correction module 104 connected in sequence, which are used to perform delay compensation, phase correction and amplitude correction on the high-frequency signal to obtain n-channel high-frequency output;

[0094] The low-frequency branch includes a second phase correction module 105, a second amplitude correction module 106 and N beam filters 107 connected in sequence, which are used to perform phase correction, amplitude correction and N-way parallel beam filtering on the low-frequency signal based on the low-frequency band directivity control algorithm to obtain N-way low-frequency output.

[0095] The beam filter 107 performs N-way parallel beam filtering based on the result of the low-frequency band directivity control algorithm;

[0096] For a given installation position of the transducer device 2, the positions of the reflective surface 3 and the audience area 4, the optimal directivity pattern of the transducer device 2 can be calculated to achieve the goal of uniformly covering the audience area 4. It is relatively easy to achieve the target directivity model of the high-frequency speaker using physical structure design, while the low-frequency speaker uses beamforming to achieve the target directivity.

[0097] Set M control points Φ={Φ1, Φ2, ..., Φ M}, where Φ i is the spherical coordinate angle of the ith control point.

[0098] The output beam of the low frequency loudspeaker array is targeted at each control point to be d(Φ) =

[0099] [d(Φ1),d(Φ2),…,d(Φ M )] T , where d(Φ) is the directivity pattern setting of the path from the center of the transducer device 2 to the reflection of the screen to the audience area along the corresponding spatial angle.

[0100] Specifically, if the space angle Φ i The corresponding travel path is r i , then its corresponding target can be set to d(Φ i )=r i R, which ensures that the intensity of the reflected sound reaching each position in the audience area is basically the same.

[0101] If the corresponding space angle Φ i The radiated sound is directly transmitted to the audience area, that is, there is no path reflected from the screen to the audience area, then the corresponding target can be set to d(Φ i )=0 to reduce the sound radiated directly from the transducer device to the audience area.

[0102] Based on the above analysis, the low-frequency band directivity control algorithm calculates the filter coefficient of the beam filter 107 corresponding to each low-frequency speaker 201 according to the position of each low-frequency speaker 201, so as to control the overall radiation directivity of the low-frequency speaker array to match the directivity of the high-frequency working frequency band of the speaker, so that the full-band sound of the speaker reflected by the reflection surface 3 covers the audience area 4, and the directly radiated sound will not spread into the audience area 4. The details are as follows:

[0103] The complex weight coefficients of the beam filters 107 corresponding to the low-frequency speakers are obtained by solving the following objective function:

[0104] min‖h(ω,X)‖1(2)

[0105] st ‖G(ω,Φ,X)h(ω,X)-d(ω,Φ)‖2≤∈ (3)

[0106] Among them, ∈ is a parameter used to control the accuracy and robustness of the beam;

[0107] ‖·‖1, ‖·‖2 are 1-norm and 2-norm;

[0108] The value range of ω is 0~2πf c Between c is the crossover frequency;

[0109] d(ω,Φ) is the directivity target of the path from the center of the low-frequency speaker array to the corresponding spatial angle Φ reflected by the screen to the audience area at the angular frequency ω;

[0110] G(ω,Φ,X) is a transfer function matrix from each low frequency loudspeaker 201 to each control point. The element in the i-th row and j-th column of G(ω,Φ,X) represents the transfer function from the j-th low frequency loudspeaker to the i-th control point, which can be determined by actual measurement or simulation.

[0111] h(ω,X)=[h(ω,X1),h(ω,X2),…,h(ω,X N )] T is the complex weight coefficient of the N beam filters 107 at the angular frequency ω, where h(ω,X i ) represents the i The complex weight coefficient of the beam filter 107 corresponding to the low-frequency speaker.

[0112] Φ={Φ1,Φ2,…,Φ M} are the spatial angles of M control points distributed on a sphere with a distance R from the center of the low frequency speaker array;

[0113] d(Φ)=[d(Φ1),d(Φ2),…,d(Φ M )] T, if the space angle Φ i The corresponding path reflected from the screen to the audience area is r i , then d(Φ i )=r i ·R, if the space angle Φ i The radiated sound is directly transmitted to the audience area, and there is no path reflected from the screen to the audience area. Then d(Φ i )=0.

[0114] Since the above optimization problem belongs to a convex optimization problem, a related convex optimization algorithm can be used to quickly solve h(ω,X), thereby obtaining the beam filter 107 corresponding to each low-frequency speaker 201.

[0115] Further preferably, since the beam filter 107 causes a delay in the low-frequency signal relative to the high-frequency signal, the present invention performs delay compensation on the high-frequency signal. That is, since the low-frequency branch performs beam filtering, the filtering causes a certain delay in the low-frequency branch relative to the original signal. Therefore, in order to ensure that the low-frequency branch and the high-frequency branch are aligned in time, a certain delay is required for the high-frequency branch. The delay measurement method is:

[0116] The sound wave arrival times t1 and t2 from the low-frequency speaker array and the high-frequency speaker including the beam filter to the measuring point at a distance R from the transducer device 2 are measured respectively. The delay for the high-frequency speaker should be τ=t2-t1.

[0117] In addition, phase and amplitude correction can be applied to the low-frequency branch and the high-frequency branch so that they are phase-added in the crossover frequency range. The general calculation steps of the correction filter are:

[0118] Select M measurement points, distributed in the main directivity range, measure the phase and amplitude responses from the device to each measurement point in the anechoic chamber, and average the phase and amplitude responses of the M measurement points. Then the difference between it and the target frequency response is the response of the phase correction and amplitude correction filters of the low-frequency and high-frequency branches.

[0119] Further preferably, the present invention performs phase and amplitude correction on the high frequency signal and the low frequency signal so that they are phase added in the range of the crossover frequency. The general calculation steps of the correction filter are:

[0120] Select m measurement points distributed in the directivity rangeΩ={Ω1,Ω2,…,Ω m}, generally uniformly selected, for example, if the target directivity range is -10° to +10°, the number of measurement points is 5, then the selected measurement point angles are {-10°, -5°, 0°, 5°, 10°}. Measure the response A(ω,Ω) of the transducer device 2 to each measurement point in the anechoic chamber i ), A(ω,Ωi ) is a complex exponential, whose magnitude represents the magnitude response and phase represents the phase response;

[0121] Average the responses of the m measurement points to obtain the mean phase amplitude response

[0123] Calculate the mean phase magnitude response The difference between the target frequency response D(ω) The magnitude and phase of P(ω) are used as the responses of the amplitude correction and phase correction filters.

[0124] Embodiment 2 of the present invention provides a screen reflection sound generation method, comprising:

[0125] The signal processing module 1 performs high-frequency signal delay compensation and low-frequency directivity control after frequency division of the input signal, thereby obtaining n-channel high-frequency output and N-channel low-frequency output;

[0126] The power amplifier amplifies the n high-frequency outputs and the N low-frequency outputs of the signal processing module 1 and feeds them to the n high-frequency speakers 202 and the N low-frequency speakers 201 of the transducer device 2 respectively;

[0127] The transducer device 2 radiates the n high-frequency outputs and N low-frequency outputs received by the n high-frequency speakers 202 and the N low-frequency speakers 201 to the reflecting surface 3 .

[0128] Through the high-frequency signal delay compensation and the directivity control of the low-frequency band, the n-way high-frequency output and the N-way low-frequency output radiated to the reflecting surface 3 can be controlled to achieve the matching of the directivity of the high-frequency working frequency band and the directivity of the low-frequency working frequency band of the speaker, and then the directivity control of the full-band of the speaker is achieved, so that the full-band sound of the speaker reflected by the reflecting surface 3 covers the audience area 4, and the directly radiated sound will not spread to the audience area 4.

[0129] Embodiment 3 of the present invention provides a terminal, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method.

[0130] Embodiment 4 of the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when executed by a processor.

[0131] Compared with the prior art, the beneficial effects of the present invention include at least:

[0132] The sound generation system of the present invention comprises a transducer device and a signal processing module matched therewith for processing audio signals, wherein the transducer device integrates a high-frequency speaker and a group of low-frequency speakers into one body and places them in front of a reflective screen, and the signal processing module uses beamforming and other related algorithms to precisely control the directivity of a group of low-frequency speakers so that their radiation characteristics achieve similar effects to those of high-frequency speakers, thereby ensuring that the direct sound from the speakers will not diffuse to the audience area, but will be radiated to the audience through the reflection of the reflective screen in the full frequency band.

[0133] The present invention integrates the low-frequency speaker and the high-frequency speaker into one, so that the acoustic center of the sound wave radiated by the low-frequency speaker array and the acoustic center of the sound wave radiated by the high-frequency speaker can be approximately in the same spatial position, and the travel path of the sound emitted by the two to any audience point is basically the same, and there is no need to perform additional delay compensation on the low-frequency speaker. At the same time, each frequency band of the sound can arrive at the audience synchronously, thereby ensuring the spatial precise positioning effect of the sound and better sound quality performance.

[0134] The high-frequency speaker part of the present invention uses a transducer device with strong directivity such as a horn, and the low-frequency branch determines the filter coefficient of each beam filter through a low-frequency band directivity control algorithm to implement low-frequency branch beam control. Specifically, by minimizing the 1-norm of the complex weight coefficients of N beam filters at the angular frequency ω, it can ensure that the target response is as close as possible while using fewer low-frequency speakers, and the number of low-frequency speakers required is small, which significantly reduces the cost.

[0135] Compared with the commonly used beam control method in the prior art, the low-frequency band directivity control algorithm of the present invention distributes the control points in three-dimensional space, and the directivity target is calculated according to the reflection path, which can effectively control the beam effect in an environment taking screen reflection into account.

[0136] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0137] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0138] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0139] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A screen reflection sound system, characterized in that: The invention comprises a signal processing module, a power amplifier and a transducer device; wherein the transducer device comprises n high-frequency speakers and N low-frequency speakers, wherein n is greater than or equal to 1, and N is greater than or equal to 2; The signal processing module is used to perform high-frequency signal delay compensation and low-frequency directivity control on the input signal after frequency division, so as to obtain n-channel high-frequency output and N-channel low-frequency output; The power amplifier is used to amplify the power of the n high-frequency outputs and the N low-frequency outputs of the signal processing module and feed them to the n high-frequency speakers and the N low-frequency speakers in the transducer device respectively; The transducer device is arranged opposite to the reflective surface, and the reflective surface is arranged opposite to the audience area; The transducer device is used to radiate the high-frequency output and the low-frequency output received by the high-frequency speaker and the low-frequency speaker to the reflecting surface.

2. A screen reflection sound system according to claim 1, characterized in that: The transducer device is arranged above the center of the audience area, above the left side of the audience area, above the right side of the audience area or below the audience area.

3. The screen reflection sound system according to claim 1, characterized in that: In the transducer device, the high-frequency speaker is located in front of the box, facing the reflecting surface; Among the N low-frequency speakers, at least one woofer is arranged in front of the box, facing the reflecting surface, and at least one woofer is arranged on the side, back or bottom of the box.

4. The screen reflection sound system according to claim 1, characterized in that: The transducer device also includes a phase inversion hole for expanding low-frequency sound waves.

5. The screen reflection sound system according to claim 1, characterized in that: The number of the transducer devices is K, and the K transducer devices are combined to enhance the directivity control effect and increase the maximum sound pressure level. The combination form is that the K transducer devices are connected up and down and arranged in a linear or J-shaped transducer device array, wherein each transducer device can perform relative pitch angle adjustment.

6. The screen reflection sound system according to claim 1, characterized in that: The signal processing module includes a frequency divider, a high-frequency branch and a low-frequency branch; The frequency divider is used to perform frequency division, divide the input signal into a low-frequency signal and a high-frequency signal, and transmit the signals to the low-frequency branch and the high-frequency branch respectively; The high-frequency branch is used to perform delay compensation, phase correction and amplitude correction on the high-frequency signal to obtain n-channel high-frequency outputs; The low-frequency branch is used to perform phase correction, amplitude correction and N-way parallel beam filtering on the low-frequency signal based on a low-frequency band directivity control algorithm to obtain N-way low-frequency outputs.

7. The screen reflection sound system according to claim 6, characterized in that: The frequency divider uses a frequency division frequency f of the low-frequency signal and the high-frequency signal. c satisfy: Where c is the speed of sound and d is the minimum distance between different low-frequency speakers.

8. The screen reflection sound system according to claim 6, characterized in that: The high-frequency branch includes a delay module, a first phase correction module and a first amplitude correction module connected in sequence, which respectively perform delay compensation, phase correction and amplitude correction on the high-frequency signal; The low-frequency branch includes a second phase correction module, a second amplitude correction module and N beam filters connected in sequence, which respectively perform phase correction, amplitude correction and N-way parallel beam filtering based on a low-frequency directivity control algorithm on the low-frequency signal.

9. A screen reflection sound system according to any one of claims 1, 6 or 8, characterized in that: The compensation time τ of the delay compensation is t2-t1, where t1 is the arrival time of the sound wave from the low-frequency speaker array to the measuring point at a distance R from the transducer device, and t2 is the arrival time of the sound wave from the high-frequency speaker to the measuring point at a distance R from the transducer device.

10. A screen reflection sound system according to claim 6 or 8, characterized in that: The phase correction and amplitude correction methods of the low-frequency branch are the same as those of the high-frequency branch, and the phase correction and amplitude correction methods are: Select m measurement points distributed in the directivity rangeΩ={Ω1,Ω2,…,Ω m }, measure the response A(ω,Ω from the transducer device to each measurement point in the anechoic chamber i ), where the magnitude represents the magnitude response and the phase represents the phase response; Average the responses of the m measurement points to obtain the mean phase amplitude response Calculate the mean phase magnitude response The difference between the target frequency response D(ω) The magnitude and phase of P(ω) are used as the responses of the amplitude correction and phase correction filters.

11. The screen reflection sound system according to claim 8, characterized in that: The N beam filters determine the filter coefficient of each beam filter based on the low-frequency band directivity control algorithm, as follows: By solving the following objective function, the complex weight coefficients of the beam filters corresponding to each low-frequency speaker are obtained: min‖h(ω,X)‖1(2) st ‖G(ω,Φ,X)h(ω,X)-d(ω,Φ)‖2≤∈ (3) Among them, ∈ is a parameter used to control the accuracy and robustness of the beam; ‖·‖1, ‖·‖2 are 1-norm and 2-norm; The value range of ω is 0~2πf c Between c is the crossover frequency; d(ω,Φ) is the directivity target of the path from the center of the low-frequency speaker array to the corresponding spatial angle Φ reflected by the screen to the audience area at the angular frequency ω; G(ω,Φ,X) is the transfer function matrix from each low frequency loudspeaker to each control point. The i-th row and j-th column element of G(ω,Φ,X) represents the transfer function from the j-th low frequency loudspeaker to the i-th control point. h(ω,X)=[h(ω,X1),h(ω,X2),…,h(ω,X N )] T is the complex weight coefficient of the N beam filters at the angular frequency ω, where h(ω,X i ) represents the i The complex weight coefficient of the beam filter corresponding to the low-frequency speaker, that is, the filter coefficient.

12. The screen reflection sound system according to claim 11, characterized in that: Φ={Φ1,Φ2,…,Φ M } are the spatial angles of M control points distributed on a sphere with a distance R from the center of the low frequency speaker array; d(Φ)=[d(Φ1),d(Φ2),…,d(Φ M )] T , if the space angle Φ i The corresponding path reflected from the screen to the audience area is r i , then d(Φ i )=r i ·R, if the space angle Φ i The radiated sound is directly transmitted to the audience area, and there is no path reflected from the screen to the audience area. Then d(Φ i )=0.

13. A screen reflection sound-raising method, using the system according to any one of claims 1 to 12, characterized in that: The method comprises: The signal processing module divides the input signal and performs high-frequency signal delay compensation and low-frequency directivity control to obtain n-channel high-frequency output and N-channel low-frequency output; The power amplifier amplifies the n high-frequency outputs and the N low-frequency outputs of the signal processing module and feeds them to the n high-frequency loudspeakers and the N low-frequency loudspeakers of the transducer device respectively; The transducer device radiates the n-channel high-frequency outputs and the N-channel low-frequency outputs received by the n high-frequency loudspeakers and the N low-frequency loudspeakers to the reflecting surface.

14. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to claim 13.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to claim 13 are implemented.

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