CN1596037A - Signal processing method for three-loudspeaker virtual 5.1 channel surround sound - Google Patents

Abstract

Translated fromChinese

本发明公开了一种三扬声器虚拟5.1通路环绕声的信号处理方法，它先输入5.1通路信号L₀、R₀、C₀、LS₀、RS₀和LFE₀；然后将信号L₀、R₀分别馈给左、右扬声器，将信号C₀、LS₀、RS₀和LFE₀经过处理后馈给扬声器；最后分别对馈给左、右扬声器和高频中置扬声器的信号进行混合，得到L″、R″、C″三个信号，然后分别馈给布置在±30°的左、右扬声器和0°的高频中置扬声器重发。本发明用左、右扬声器和一个高频中置扬声器进行重发，产生整个前半平面的环绕声效果，节省了重发扬声器；另外还将左、右扬声器布置在±30°的位置，并采用高频中置扬声器，扩大了听音区域，信号处理简单，并且与双通路立体声的扬声器布置兼容，特别适用于电视和多媒体计算机。

The invention discloses a three-speaker virtual 5.1 channel surround sound signal processing method, which firstly inputs the 5.1 channel signals L₀ , R₀ , C 0 , LS_0, RS₀ and LFE₀ ; then signals L₀ , R₀ Feed to the left and right speakers respectively, and feed the signals C₀ , LS₀ , RS₀ and LFE₀ to the speakers after processing; finally mix the signals fed to the left and right speakers and the high-frequency center speaker respectively to obtain L ″, R″, C″ three signals, then respectively fed to the left and right loudspeakers arranged at ± 30° and the high-frequency center loudspeaker at 0° to resend. The present invention uses the left and right loudspeakers and a high-frequency center The speaker retransmits to produce the surround sound effect of the entire front half plane, which saves the retransmission speaker; in addition, the left and right speakers are arranged at ±30°, and the high-frequency center speaker is used to expand the listening area and signal Simple to handle and compatible with two-way stereo speaker arrangements, especially for TVs and multimedia computers.

Description

Translated fromChinese

三扬声器虚拟5.1通路环绕声的信号处理方法Signal processing method for three-speaker virtual 5.1-channel surround sound

                         技术领域Technical field

本发明涉及5.1通路环绕声技术领域，具体涉及一种三扬声器虚拟5.1通路环绕声的信号处理方法。The invention relates to the technical field of 5.1-channel surround sound, in particular to a signal processing method for three-speaker virtual 5.1-channel surround sound.

                         背景技术 Background technique

5.1通路系统已被推荐为环绕声的国际标准，并已被广泛应用于家用声重发。它采用前方左L₀、中C₀、右R₀以及左环绕LS₀、右环绕RS₀共五个独立的全频带通路及扬声器，再加上一路可选择的低频效果通路LFE₀，从而重发出环绕倾听者的声音听觉效果。按国际电信联盟(ITU)推荐的标准，各扬声器的方位角分别为(水平面内坐标选取为-180°＜θ≤180°，θ＝0°为正前方，θ＝90°为正左方)：The 5.1 channel system has been recommended as the international standard for surround sound, and has been widely used in home sound reproduction. It uses front left L₀ , center C₀ , right R₀ , left surround LS₀ , and right surround RS₀ , five independent full-band channels and speakers, plus a selectable low-frequency effect channel LFE₀ , thus reproducing Produces the audible effect of sound that surrounds the listener. According to the standard recommended by the International Telecommunication Union (ITU), the azimuth angles of each loudspeaker are respectively (the coordinates in the horizontal plane are selected as -180°<θ≤180°, θ=0° is the front, θ=90° is the left) :

θ_L＝30°θ_R＝-30°θ_C＝0°θ_LS＝110°θ_RS＝-110°  (1)但是5.1通路系统需要多个独立的扬声器，较为复杂。而对于电视及多媒体计算机等应用，以及由于室内条件的限制，有时并不一定适合布置环绕声的多个扬声器。θ_L ＝30°θ_R ＝-30°θ_C ＝0°θ_LS ＝110°θ_RS ＝-110° (1) However, the 5.1 channel system requires multiple independent speakers, which is relatively complicated. For applications such as televisions and multimedia computers, and due to the limitations of indoor conditions, sometimes it is not necessarily suitable for arranging multiple speakers for surround sound.

近年，国外有人提出了5.1通路环绕声的两扬声器虚拟重发系统，如图1所示。其基本原理是：将(来自DVD等的)5.1通路信号经过头相关传输函数(HRTF)进行信号处理和混合后(这里略去了低频效果通路LFE₀，事实上，对LFE通路信号的处理和C₀信号是类似的)，变成两通路信号，再利用一对布置在前方±30°的真实左、右扬声器进行重发，从而将多通路系统的其它扬声器虚拟出来，达到节省扬声器，简化系统的目的。这类系统普遍存在一定的缺陷，特别是听音区域较窄。In recent years, someone abroad has proposed a two-speaker virtual retransmission system for 5.1-channel surround sound, as shown in Figure 1. The basic principle is: after the 5.1 channel signal (from DVD, etc.) is processed and mixed through the head-related transfer function (HRTF) (the low frequency effect channel LFE₀ is omitted here, in fact, the processing of the LFE channel signal and C₀ signals are similar), and become two-channel signals, and then use a pair of real left and right speakers arranged at ±30° in front to retransmit, thereby virtualizing other speakers of the multi-channel system, saving speakers and simplifying purpose of the system. This type of system generally has certain defects, especially the narrow listening area.

为了扩大听音区域，O.Kirkeby提出一种称为“立体声偶极”的虚拟重发系统，它的基本原理和两扬声器虚拟重发系统一样，但将左、右扬声器布置在±5°的位置上。由于“立体声偶极”需要对信号的低频部分作较大的提升，信号处理较为困难。In order to expand the listening area, O. Kirkeby proposed a virtual retransmission system called "stereo dipole". Its basic principle is the same as that of the two-speaker virtual retransmission system, but the left and right speakers are arranged at ±5°. position. Since the "stereo dipole" needs to greatly enhance the low frequency part of the signal, the signal processing is more difficult.

而J.L.Bauck和D.H.Copper提出采用前方左、中、右三个全频带扬声器的三扬声器虚拟重发系统，如图2所示。其基本原理是：将(来自DVD等的)5.1通路信号经过头相关传输函数(HRTF)进行信号处理和混合后，变成三通路信号，再利用前方布置在±30°和0°的真实的左、右、中置扬声器进行重发。虽然三扬声器系统可提高虚拟声像的稳定性，但在实际应用中，由于正前方已放置了电视机(或计算机的显示器)，再布置一个全频带的中置扬声器较困难，通常只能将中置扬声器布置在电视机的上方。但这经常会导致中置与左右扬声器不在同一水平面上，以及中置扬声器系统的高低音单元不在正前方的位置，这些都会影响重发声像的定位。J.L.Bauck and D.H.Copper proposed a three-speaker virtual retransmission system using three full-band speakers in the front left, center, and right, as shown in Figure 2. The basic principle is: after the 5.1-channel signal (from DVD, etc.) is processed and mixed by the head-related transfer function (HRTF), it becomes a three-channel signal, and then the real Left, right, and center speakers for retransmission. Although the three-speaker system can improve the stability of the virtual sound image, in practical applications, since a TV (or computer monitor) has been placed directly in front, it is difficult to arrange a full-range center speaker. The center speaker is placed above the TV. However, this often results in that the center and left and right speakers are not on the same level, and the high and bass units of the center speaker system are not in the front position, which will affect the positioning of the reproduction sound image.

J.L.Bauck提出采用两对不同张角的扬声器的虚拟重发系统，如图3所示。其中张角较大(如布置在电视机两边)的一对扬声器重发低频虚拟声信号，另一对体积较小(布置在电视机上方)的“立体声偶极”重发高频虚拟声信号。虽然这种重发方法改善了高频声像的稳定性，但信号处理和扬声器布置较为复杂，且不易与普通立体声兼容。J.L.Bauck proposed a virtual retransmission system using two pairs of loudspeakers with different opening angles, as shown in Figure 3. Among them, a pair of speakers with a larger opening angle (such as arranged on both sides of the TV) retransmits low-frequency virtual sound signals, and the other pair of "stereo dipoles" with smaller volumes (arranged above the TV) retransmits high-frequency virtual sound signals . Although this retransmission method improves the stability of the high-frequency sound image, the signal processing and speaker arrangement are more complicated, and it is not easy to be compatible with ordinary stereo.

                         发明内容Contents of invention

本发明为解决上述现有技术中存在的缺陷，提供一种三扬声器虚拟5.1通路环绕声的信号处理方法，本发明采用高频中置扬声器，该方法能扩大重发时的听音区域，在电视、多媒体计算机等实际应用中扬声器也易于布置，同时也和普通立体声兼容。In order to solve the defects in the above-mentioned prior art, the present invention provides a signal processing method for three-speaker virtual 5.1 channel surround sound. The present invention adopts a high-frequency center speaker, and the method can expand the listening area when retransmitting. Speakers in practical applications such as TVs and multimedia computers are also easy to arrange, and are also compatible with ordinary stereo.

本发明的三扬声器虚拟5.1通路环绕声的信号处理方法，包括如下步骤：The signal processing method of the virtual 5.1 path surround sound of three loudspeakers of the present invention comprises the following steps:

第一步：输入原始的5.1通路信号：左通路信号L₀、右通路信号R₀、中心通路信号C₀、左环绕通路信号LS₀、右环绕通路信号RS₀、低频效果通路信号LFE₀；Step 1: Input the original 5.1 channel signals: left channel signal L₀ , right channel signal R₀ , center channel signal C₀ , left surround channel signal LS₀ , right surround channel signal RS₀ , low frequency effect channel signal LFE₀ ;

第二步：将原始的左、右通路信号L₀、R₀分别直接馈到左、右全频带扬声器的信号混合器；Step 2: Feed the original left and right channel signals L₀ and R₀ directly to the signal mixer of the left and right full-band speakers respectively;

第三步：将原始的中心通路信号C₀经传输函数为H_HP的高通滤波后馈到高频中置扬声器的信号混合器，以直接产生高频的前方声像；而中心通路信号C₀经过传输函数为H_LP的低通滤波和-3dB衰减后，同时馈给左、右全频带扬声器的信号混合器，以合成低频的前方声像；Step 3: Feed the original central channel signal C₀ to the signal mixer of the high-frequency center speaker after high-pass filtering with the transfer function H_HP , so as to directly generate the high-frequency front sound image; and the central channel signal C₀ After low-pass filtering and -3dB attenuation with the transfer function_HLP , it is fed to the signal mixer of the left and right full-range speakers at the same time to synthesize the low-frequency front sound image;

第四步：原始的左环绕通路信号LS₀经过虚拟处理，也就是分别与三个从水平面90°头相关传输函数得到的函数A’(90°，ω)、B’(90°，ω)、D’(90°，ω)进行频域相乘，得到三个信号A’(90°，ω)LS₀、B’(90°，ω)LS₀、D’(90°，ω)LS₀，然后分别馈到左、右全频带扬声器和高频中置扬声器的信号混合器，虚拟出90°方向的左环绕扬声器；Step 4: The original left surround channel signal LS₀ is subjected to virtual processing, that is, it is respectively combined with three functions A'(90°, ω) and B'(90°, ω) obtained from the 90° head-related transfer function of the horizontal plane , D'(90°, ω) are multiplied in the frequency domain to obtain three signals A'(90°, ω)LS₀ , B'(90°, ω)LS₀ , D'(90°, ω)LS₀ , and then fed to the signal mixer of the left and right full-range speakers and the high-frequency center speaker respectively, to virtualize the left surround speaker in a 90° direction;

第五步：原始的右环绕通路信号RS₀经过虚拟处理，也就是分别与三个从水平面-90°头相关传输函数得到的函数A’(-90°，ω)、B’(-90°，ω)、D’(-90°，ω)进行频域相乘，得到三个信号A’(-90°，ω)RS₀、B’(-90°，ω)RS₀、D’(-90°，ω)RS₀，然后分别馈到左、右全频带扬声器和高频中置扬声器的信号混合器，虚拟出-90°方向的右环绕扬声器；Step 5: The original right surround channel signal RS₀ undergoes virtual processing, that is, it is respectively compared with the three functions A'(-90°, ω), B'(-90° , ω), D'(-90°, ω) are multiplied in the frequency domain to obtain three signals A'(-90°, ω)RS₀ , B'(-90°, ω)RS₀ , D'( -90°, ω) RS₀ , and then fed to the signal mixer of the left and right full-range speakers and the high-frequency center speaker respectively, virtualizing the right surround speaker in the -90° direction;

第六步：原始的低频效果通路信号LFE₀经-3dB衰减后，同时馈给左、右全频带扬声器的信号混合器；Step 6: After the original low-frequency effect channel signal LFE₀ is attenuated by -3dB, it is simultaneously fed to the signal mixer of the left and right full-band speakers;

第七步：分别对馈给左、右全频带扬声器和高频中置扬声器的输入信号进行混合(相加)，得到L″、R″、C″三个信号，然后分别馈给布置在±30°的左、右全频带扬声器和0°的高频中置扬声器重发。Step 7: Mix (add) the input signals fed to the left and right full-band speakers and the high-frequency center speaker respectively to obtain three signals of L″, R″ and C″, and then feed them respectively to the 30° left and right full-range speakers and 0° high-frequency center speaker retransmission.

本发明的原理是：Principle of the present invention is:

在采用扬声器的虚拟声重发中，倾听者偏离理想的听音位置时，双耳处的迭加声压将会改变。但对一定偏离距离，由于低频声波的波长较长，双耳处迭加声压的相位改变较少，因而引起的声像畸变较少；反之高频声波的波长较短，声像畸变较大。本发明提出对高频部分信号，采用左、中、右三个扬声器重发，以提高声像的稳定性，扩大听音区域。低频部分信号是由左、右两扬声器重发，由于低频声像随倾听者的位置漂移较少，所以也可以接受。实际应用中，可采用两个全频带的左、右扬声器，而中置扬声器可采用体积较小的高频扬声器，这样也容易布置(如中置扬声器布置在电视机的上方)。同时，对于低频信号，由于左、右扬声器之间的张角不至于太小(相对立体偶极而言)，因而不会给信号处理带来太大的困难，并且与普通的双通路立体声的扬声器布置兼容。In virtual sound reproduction using loudspeakers, when the listener deviates from the ideal listening position, the superimposed sound pressure at both ears will change. But for a certain deviation distance, because the wavelength of the low-frequency sound wave is longer, the phase change of the superimposed sound pressure at the ears is less, thus causing less sound image distortion; on the contrary, the wavelength of the high-frequency sound wave is shorter, and the sound image distortion is larger . The present invention proposes to retransmit the high-frequency part of the signal by using the left, middle and right loudspeakers to improve the stability of the sound image and expand the listening area. The low-frequency part of the signal is reproduced by the left and right speakers. Since the low-frequency sound image drifts less with the position of the listener, it is also acceptable. In practical applications, two full-band left and right speakers can be used, and the center speaker can use a smaller high-frequency speaker, which is also easy to arrange (for example, the center speaker is arranged above the TV). At the same time, for low-frequency signals, since the opening angle between the left and right speakers is not too small (compared to the stereo dipole), it will not bring too much difficulty to the signal processing, and it is different from the ordinary two-channel stereo Speaker arrangements are compatible.

本发明与现有技术相比，具有如下优点和有益效果：Compared with the prior art, the present invention has the following advantages and beneficial effects:

1.本发明对来自DVD等的5.1通路环绕声的5+1个独立原始(也可以是Dolby Surround的四路)信号进行处理后，用前方一对真实的左、右全频带扬声器和一个高频中置扬声器进行重发，可产生整个前半平面的环绕声效果，从而达到节省重发扬声器的目的；1. After the present invention processes 5+1 independent original (also can be the four-way of Dolby Surround) signals from the 5.1 path surround sound of DVD etc., use a pair of real left and right full-range loudspeakers and a high-frequency speaker in the front The frequency center speaker can be used for retransmission, which can produce the surround sound effect of the entire front half plane, so as to achieve the purpose of saving retransmission speakers;

2.本发明将重发虚拟环绕声的一对左、右全频带扬声器布置在±30°的位置，并采用高频中置扬声器，该布置可扩大听音区域，方便于实际应用，信号处理也简单可行，并且与普通的双通路立体声的扬声器布置兼容，这种新的扬声器布置特别适用于电视和多媒体计算机的应用；2. The present invention arranges a pair of left and right full-band speakers reproducing virtual surround sound at a position of ± 30°, and adopts a high-frequency center speaker. This arrangement can expand the listening area, which is convenient for practical application and signal processing. Also simple and feasible, and compatible with common two-way stereo speaker arrangements, this new speaker arrangement is especially suitable for television and multimedia computer applications;

3.本发明可采用通用信号处理芯片(DSP硬件)电路或专用的集成电路实现，也可采用算法语言(如VC++)编制的软件在多媒体计算机上实现；3. the present invention can adopt general signal processing chip (DSP hardware) circuit or special-purpose integrated circuit to realize, also can adopt the software of algorithmic language (as VC ++) compilation to realize on the multimedia computer;

4.本发明可作为算法写入专用硬件芯片，用于DVD、电视(包括DTV和HDTV)、家庭影院等方面的声音重发，也可作为硬件或软件用在多媒体计算机的声音重发。4. The present invention can be written into a dedicated hardware chip as an algorithm for sound reproduction in DVD, TV (comprising DTV and HDTV), home theater, etc., and can also be used in multimedia computer sound reproduction as hardware or software.

                         附图说明Description of drawings

图1是5.1通路环绕声的两扬声器虚拟重发系统；Figure 1 is a two-speaker virtual retransmission system for 5.1 channel surround sound;

图2是三扬声器虚拟声重发系统；Fig. 2 is a three-speaker virtual sound reproduction system;

图3是两对不同张角的扬声器的虚拟重发系统；Fig. 3 is the virtual retransmission system of two pairs of loudspeakers with different opening angles;

图4是本发明的三扬声器虚拟5.1通路环绕声的信号处理方法的原理图；Fig. 4 is the schematic diagram of the signal processing method of the virtual 5.1 channel surround sound of three loudspeakers of the present invention;

图5是图4中5.1通路环绕声的扬声器布置及扬声器到双耳的传输示意图；Fig. 5 is a schematic diagram of the arrangement of speakers for 5.1 channel surround sound in Fig. 4 and the transmission from the speakers to both ears;

图6是采用高频中置扬声器虚拟声的原理图；Fig. 6 is a schematic diagram of a virtual sound using a high-frequency center speaker;

图7是本发明的信号处理流程和扬声器布置图；Fig. 7 is a signal processing flow diagram and a loudspeaker arrangement diagram of the present invention;

图8是信号处理软件的流程图；Fig. 8 is the flowchart of signal processing software;

图9是声像定位的实验结果图。Fig. 9 is a graph of experimental results of sound image localization.

                       具体实施方式 Detailed ways

下面结合附图对本发明作进一步地说明。The present invention will be further described below in conjunction with accompanying drawing.

图4是本发明的三扬声器虚拟5.1通路环绕声的信号处理方法的原理图，它对输入的5.1通路环绕声信号进行虚拟处理后，用一对布置在前方±30°的左、右全频带扬声器和一个布置在正前方0°的高频中置扬声器重发。Fig. 4 is the schematic diagram of the signal processing method of the three-speaker virtual 5.1 channel surround sound of the present invention, after it carries out virtual processing to the input 5.1 channel surround sound signal, a pair of left and right full frequency bands arranged at the front ± 30° The loudspeaker is reproduced with a high-frequency center speaker arranged at 0° directly in front.

对于5.1通路环绕声原始的左、右通路信号L₀和R₀，本发明是分别直接馈给左、右全频带扬声器，以产生前方范围的立体声像分布。For the original left and right channel signals L₀ and R₀ of the 5.1-channel surround sound, the present invention directly feeds the left and right full-band speakers respectively to generate stereo image distribution in the front range.

对于5.1通路环绕声原始的中心通路信号C₀，本发明利用高通和低通滤波器将其高频和低频部分分开。其中高频部分是直接馈给高频中置扬声器重发，而低频部分经-3dB衰减后同时馈给左、右全频带扬声器重发(衰减-3dB是为保证信号的功率守恒)，以产生正前方的虚拟声像。For the original central channel signal C₀ of the 5.1-channel surround sound, the present invention uses high-pass and low-pass filters to separate its high-frequency and low-frequency parts. The high-frequency part is directly fed to the high-frequency center speaker for retransmission, while the low-frequency part is attenuated by -3dB and then fed to the left and right full-band speakers for retransmission (the attenuation of -3dB is to ensure the power conservation of the signal) to generate The virtual sound image right in front of you.

对于5.1通路环绕声原始的低频效果通路信号LFE₀，本发明是经-3dB衰减后同时馈给左、右全频带扬声器重发。For the original low-frequency effect channel signal LFE₀ of the 5.1-channel surround sound, the present invention feeds the left and right full-band speakers for retransmission after being attenuated by -3dB.

对于5.1通路环绕声原始的左、右环绕通路信号LS₀、RS₀，本发明提出利用高通和低通滤波器将其高频和低频部分分开。对信号的低频部分，采用左、右两真实的全频带扬声器进行虚拟重发；对信号的高频部分，采用左、右全频带扬声器和高频中置扬声器进行虚拟重发，也就是利用左、右全频带扬声器和高频中置扬声器将两个环绕扬声器虚拟出来。由于左、右环绕通路信号LS₀、RS₀的低频和高频部分分别用两个和三个扬声器进行虚拟重发，因而信号的高、低频部分的处理是不同的。For the original left and right surround channel signals LS₀ , RS₀ of 5.1 channel surround sound, the present invention proposes to use high-pass and low-pass filters to separate their high-frequency and low-frequency parts. For the low-frequency part of the signal, use the left and right real full-band speakers for virtual retransmission; for the high-frequency part of the signal, use the left and right full-band , right full-range speaker, and high-frequency center speaker virtualize the two surround speakers. Since the low frequency and high frequency parts of the left and right surround path signals LS₀ , RS₀ are virtually retransmitted by two and three loudspeakers respectively, the processing of the high and low frequency parts of the signals is different.

图5是图4中5.1通路环绕声的扬声器布置及扬声器到双耳的传输示意图。以左环绕通路信号LS₀为例，在真实的5.1通路环绕声重发中，布置在θ＝θ_LS方向的左环绕扬声器到双耳的频域传输函数(HRTF)分别为H_lLS、H_rLS，它产生的双耳声压P_L，P_R分别为：Fig. 5 is a schematic diagram of speaker arrangement and transmission from the speaker to both ears of the 5.1-channel surround sound in Fig. 4 . Taking the left surround channel signal LS₀ as an example, in the real 5.1 channel surround sound reproduction, the frequency domain transfer functions (HRTF) from the left surround speaker arranged in the direction of θ = θ_LS to the binaural ears are H_lLS , H_rLS respectively , the binaural sound pressures P_L and P_R produced by it are:

      P_L＝H_lLS LS₀    P_R＝H_rLS LS₀  (2)P_L ＝H_lLS LS₀ P_R ＝H_rLS LS₀ (2)

本发明中，左环绕通路信号LS₀的低频部分由布置在±30°的左、右全频带扬声器虚拟重发。设左、右全频带扬声器到倾听者双耳的四个频域传输函数(HRTF)分别为H₁₁、H_rl、H_1r、H_rr(如图1所示)，左、右全频带扬声器的信号分别为L、R，那么倾听者双耳处的声压为：In the present invention, the low-frequency part of the left surround channel signal LS₀ is virtually retransmitted by the left and right full-band speakers arranged at ±30°. Let the four frequency domain transfer functions (HRTF) from the left and right full-band speakers to the listener's ears be H₁₁ , H_rl , H_1r , and H_rr respectively (as shown in Figure 1), and the left and right full-band speakers The signals are L and R respectively, then the sound pressure at the listener's ears is:

      P_L′＝H_llL+H_lrR    P_R′＝H_rlL+H_rrR  (3)如果适当选择L和R，使得全频带扬声器重发时的双耳声压与单声源时的情况相等，也就是(2)式与(3)式相等，就可在听觉中虚拟出θ_LS方向的左环绕扬声器(声像)。考虑到扬声器布置和人类听觉器官的左右对称性，可设：H_ll＝H_rr＝α，H_lr＝H_rl＝β，由此可得：P_L ′＝H_ll L+H_lr R P_R ′＝H_rl L+H_rr R (3) If L and R are properly selected, the binaural sound pressure when the full-range speaker reproduces is the same as that of a single sound source are equal, that is, formula (2) is equal to formula (3), and the left surround speaker (sound image) in the direction of θ_LS can be virtualized in hearing. Considering the loudspeaker layout and the left-right symmetry of human auditory organs, it can be set: H_ll ＝H_rr ＝α, H_lr ＝H_rl ＝β, thus:

$\mathrm{<span><span>L</span>L</span>}<span><span>=</span>=</span>\frac{\mathrm{<span><span>\&alpha;</span>\&alpha;</span>}{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>lLS</span>LS</span>}}<span><span>-</span>-</span>\mathrm{<span><span>\&beta;</span>\&beta;</span>}{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>rLS</span>wxya</span>}}}{{\mathrm{<span><span>\&alpha;</span>\&alpha;</span>}}^{\mathrm{<span><span>2</span>2</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>\&beta;</span>\&beta;</span>}}^{\mathrm{<span><span>2</span>2</span>}}}{\mathrm{<span><span>LS</span>LS</span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span>\mathrm{<span><span>R</span>R</span>}<span><span>=</span>=</span>\frac{{\mathrm{<span><span>\&alpha;H</span>\&alpha;H</span>}}_{\mathrm{<span><span>rLS</span>wxya</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>\&beta;H</span>\&beta;H</span>}}_{\mathrm{<span><span>lLS</span>LS</span>}}}{{\mathrm{<span><span>\&alpha;</span>\&alpha;</span>}}^{\mathrm{<span><span>2</span>2</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>\&beta;</span>\&beta;</span>}}^{\mathrm{<span><span>2</span>2</span>}}}{\mathrm{<span><span>LS</span>LS</span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>4</span>4</span>}<span><span>)</span>)</span>$

因而在两扬声器重发中，只要对输入的左环绕通路信号LS₀的低频部分按上式进行处理即可得到相应方向的(低频)虚拟扬声器。Therefore, in the two-speaker retransmission, as long as the low-frequency part of the input left surround channel signal LS₀ is processed according to the above formula, the (low-frequency) virtual speaker in the corresponding direction can be obtained.

本发明中，左环绕通路信号LS₀的高频部分由左、右、中三个真实扬声器进行虚拟重发。设新增加的高频中置扬声器到倾听者左、右耳的传输函数为H_lC＝H_rC＝γ(如图2所示)，和(4)式的推导类似，可以证明，当输入的左环绕通路信号LS₀的高频部分按下式处理(式中α，β同(4)式，*号表示复数共轭)，并馈给三个扬声器，即可在听觉中产生θ_LS方向的虚拟左环绕扬声器：L′＝(XH_lLS+YH_rLS)LS₀  C′＝Z(H_lLS+H_rLS)LS₀  R′＝(YH_lLS+XH_rLS)LS₀  (5)In the present invention, the high-frequency part of the left surround channel signal LS₀ is virtually retransmitted by the three real loudspeakers of the left, right and center. Assume that the transfer function of the newly added high-frequency center speaker to the left and right ears of the listener is H_lC =H_rC =γ (as shown in Figure 2), similar to the derivation of (4), it can be proved that when the input The high-frequency part of the left surround channel signal LS₀ is processed according to the following formula (in the formula, α, β are the same as formula (4), and * indicates complex conjugate), and fed to three loudspeakers, the θ_LS direction can be generated in the auditory sense The virtual left surround speaker: L′=(XH_lLS +YH_rLS )LS₀ C′=Z(H_lLS +H_rLS )LS₀ R′=(YH_lLS +XH_rLS )LS₀ (5)

$\mathrm{<span><span>X</span>x</span>}<span><span>=</span>=</span>\frac{{\mathrm{<span><span>M\&alpha;</span>M\&alpha;</span>}}^{<span><span>*</span>*</span>}<span><span>-</span>-</span>{\mathrm{<span><span>P\&beta;</span>P\&beta;</span>}}^{<span><span>*</span>*</span>}}{{\mathrm{<span><span>M</span>m</span>}}^{\mathrm{<span><span>2</span>2</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>P</span>P</span>}}^{\mathrm{<span><span>2</span>2</span>}}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span>\mathrm{<span><span>Y</span>Y</span>}<span><span>=</span>=</span>\frac{{\mathrm{<span><span>M\&beta;</span>M\&beta;</span>}}^{<span><span>*</span>*</span>}<span><span>-</span>-</span>\mathrm{<span><span>P</span>P</span>}{\mathrm{<span><span>\&alpha;</span>\&alpha;</span>}}^{<span><span>*</span>*</span>}}{{\mathrm{<span><span>M</span>m</span>}}^{\mathrm{<span><span>2</span>2</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>P</span>P</span>}}^{\mathrm{<span><span>2</span>2</span>}}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span>\mathrm{<span><span>Z</span>Z</span>}<span><span>=</span>=</span>\frac{{\mathrm{<span><span>Q\&gamma;</span>Q\&gamma;</span>}}^{<span><span>*</span>*</span>}}{{\mathrm{<span><span>M</span>m</span>}}^{\mathrm{<span><span>2</span>2</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>P</span>P</span>}}^{\mathrm{<span><span>2</span>2</span>}}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>6</span>6</span>}<span><span>)</span>)</span>$

M＝|α|²+|β|²+|γ|²  P＝|γ|²+αβ^*+βα^*  Q＝|α|²+|β|²-αβ^*-βα^*M＝|α|² +|β|² +|γ|² P＝|γ|² +αβ^* +βα^* Q＝|α|² +|β|² -αβ^* -βα^*

图6是采用高频中置扬声器虚拟声的原理图。输入的左环绕通路信号LS₀经低通和高通滤波器后，分别按(4)和(5)式进行两扬声器和三扬声器虚拟声信号处理，分别得到两组信号L、R和L’、R’、C’，再把它们混合后馈给扬声器。设低通和高通滤波器的频域传输函数分别为H_LP(ω，ω₀)、H_HP(ω，ω₀)，ω₀为滤波器的分频角频率。由图5和(4)、(5)两式，实际重发中馈给左、右和中置三个扬声器的信号分别为：Fig. 6 is a schematic diagram of a virtual sound using a high-frequency center speaker. After the input left surround channel signal LS₀ is passed through the low-pass and high-pass filters, the two-speaker and three-speaker virtual sound signals are processed according to formulas (4) and (5), respectively, and two sets of signals L, R and L', R', C', and then mix them and feed the speaker. Let the frequency-domain transfer functions of the low-pass and high-pass filters be H_LP (ω, ω₀ ) and H_HP (ω, ω₀ ), respectively, and ω₀ is the frequency-division angular frequency of the filter. From Figure 5 and formulas (4) and (5), the signals fed to the left, right and center speakers in actual retransmission are:

${\mathrm{<span><span>L</span>L</span>}}^{<span><span>\&prime;</span>\&prime;</span><span><span>\&prime;</span>\&prime;</span>}<span><span>=</span>=</span>\mathrm{<span><span>L</span>L</span>}<span><span>+</span>+</span>{\mathrm{<span><span>L</span>L</span>}}^{<span><span>\&prime;</span>\&prime;</span>}<span><span>=</span>=</span><span><span>[</span>[</span>\frac{{\mathrm{<span><span>\&alpha;H</span>\&alpha;H</span>}}_{\mathrm{<span><span>lLS</span>LS</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>\&beta;H</span>\&beta;H</span>}}_{\mathrm{<span><span>rLS</span>wxya</span>}}}{{\mathrm{<span><span>\&alpha;</span>\&alpha;</span>}}^{\mathrm{<span><span>2</span>2</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>\&beta;</span>\&beta;</span>}}^{\mathrm{<span><span>2</span>2</span>}}}{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>LP</span>LP</span>}}<span><span>(</span>(</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>,</span>,</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>)</span>)</span><span><span>+</span>+</span><span><span>(</span>(</span>{\mathrm{<span><span>XH</span>XH</span>}}_{\mathrm{<span><span>lLS</span>LS</span>}}<span><span>+</span>+</span>{\mathrm{<span><span>YH</span>YH</span>}}_{\mathrm{<span><span>rLS</span>wxya</span>}}<span><span>)</span>)</span>{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>HP</span>HP</span>}}<span><span>(</span>(</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>,</span>,</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>)</span>)</span><span><span>]</span>]</span>{\mathrm{<span><span>LS</span><figure-callout\; label="LS"\; filenames="A20041002806200201.png"\; state="\{\{state\}\}">LS</figure-callout></span>}}_{\mathrm{<span><span>0</span>0</span>}}$

${\mathrm{<span><span>R</span>R</span>}}^{<span><span>\&prime;</span>\&prime;</span><span><span>\&prime;</span>\&prime;</span>}<span><span>=</span>=</span>\mathrm{<span><span>R</span>R</span>}<span><span>+</span>+</span>{\mathrm{<span><span>R</span>R</span>}}^{<span><span>\&prime;</span>\&prime;</span>}<span><span>=</span>=</span><span><span>[</span>[</span>\frac{{\mathrm{<span><span>\&alpha;H</span>\&alpha;H</span>}}_{\mathrm{<span><span>rLS</span>wxya</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>\&beta;H</span>\&beta;H</span>}}_{\mathrm{<span><span>lLS</span>LS</span>}}}{{\mathrm{<span><span>\&alpha;</span>\&alpha;</span>}}^{\mathrm{<span><span>2</span>2</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>\&beta;</span>\&beta;</span>}}^{\mathrm{<span><span>2</span>2</span>}}}{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>LP</span>LP</span>}}<span><span>(</span>(</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>,</span>,</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>)</span>)</span><span><span>+</span>+</span><span><span>(</span>(</span>{\mathrm{<span><span>YH</span>YH</span>}}_{\mathrm{<span><span>lLS</span>LS</span>}}<span><span>+</span>+</span>{\mathrm{<span><span>XH</span>XH</span>}}_{\mathrm{<span><span>rLS</span>wxya</span>}}<span><span>)</span>)</span>{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>HP</span>HP</span>}}<span><span>(</span>(</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>,</span>,</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>)</span>)</span><span><span>]</span>]</span>{\mathrm{<span><span>LS</span><figure-callout\; label="LS"\; filenames="A20041002806200201.png"\; state="\{\{state\}\}">LS</figure-callout></span>}}_{\mathrm{<span><span>0</span>0</span>}}$

C″＝C′＝[Z(H_lLS+H_rLS)H_HP(ω，ω₀)]LS₀(7)C″=C′=[Z(H_lLS +H_rLS )H_HP (ω,ω₀ )]LS₀ (7)

其中，X、Y、Z由(6)式给出。Among them, X, Y, Z are given by (6).

低通和高通滤波器的设计与通常的扬声器系统的分频网络类似。它们的传输函数为：The design of the low-pass and high-pass filters is similar to the crossover network of a typical loudspeaker system. Their transfer functions are:

$<span><span>|</span>|</span>{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>LP</span>LP</span>}}<span><span>|</span>|</span><span><span>=</span>=</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\sqrt{\mathrm{<span><span>1</span>1</span>}<span><span>+</span>+</span>{<span><span>(</span>(</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>/</span>/</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>)</span>)</span>}^{\mathrm{<span><span>2</span>2</span>}\mathrm{<span><span>n</span>no</span>}}}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>|</span>|</span>{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>HP</span>HP</span>}}<span><span>|</span>|</span><span><span>=</span>=</span>\frac{{<span><span>(</span>(</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>/</span>/</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>)</span>)</span>}^{\mathrm{<span><span>n</span>no</span>}}}{\sqrt{\mathrm{<span><span>1</span>1</span>}<span><span>+</span>+</span>{<span><span>(</span>(</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>/</span>/</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>)</span>)</span>}^{\mathrm{<span><span>2</span>2</span>}\mathrm{<span><span>n</span>no</span>}}}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span>{<span><span>|</span>|</span>{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>LP</span>LP</span>}}<span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}<span><span>+</span>+</span>{<span><span>|</span>|</span>{\mathrm{<span><span>H</span>h</span>}}_{\mathrm{<span><span>HP</span>HP</span>}}<span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}<span><span>=</span>=</span>\mathrm{<span><span>1</span>1</span>}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>8</span>8</span>}<span><span>)</span>)</span>$

n为滤波器的阶数(这里取n＝6)，在ω＝ω₀时，滤波器有-3dB衰减，而右边的式表明滤波器的输出总功率与频率无关。n is the order number of the filter (here n=6), when ω=ω₀ , the filter has -3dB attenuation, and the formula on the right shows that the total output power of the filter has nothing to do with the frequency.

(7)式还可以写成以下的形式：(7) can also be written in the following form:

L″＝A(θ_LS，ω)LS₀  R″＝B(θ_LS，ω)LS₀  C″＝D(θ_LS，ω)LS₀L″=A(θ_LS ,ω)LS₀ R″=B(θ_LS ,ω)LS₀ C″=D(θ_LS ,ω)LS₀

                                                        (9) (9)

其中A(θ_LS，ω)、B(θ_LS，ω)和D(θ_LS，ω)分别表示(7)式给出的三个公式中方括号内的量。Among them, A(θ_LS , ω), B(θ_LS , ω) and D(θ_LS , ω) respectively represent the quantities in the square brackets in the three formulas given by (7).

(9)式表明，输入的左环绕通路信号LS₀分别与A(θ _LS，ω)、B(θ_LS，ω)、D(θ_LS，ω)三个函数进行频域相乘后即可得到L″、R″和C″，将它们分别馈给左、右全频带扬声器和高频中置扬声器后，即可虚拟出θ_LS方向的左环绕扬声器。而A、B、D三个函数是和拟产生的虚拟环绕扬声器方向θ_LS有关的。事实上，(9)式相当于把图4的信号处理的频率分频、两扬声器和三扬声器虚拟处理、信号混合等步骤合在一起进行。由于图4的系统是线性系统，这显然是可行的。Equation (9) shows that the input left surround channel signal LS₀ is multiplied by the three functions A(θ_LS , ω), B(θ_LS , ω), and D(θ_LS , ω) respectively in the frequency domain. After obtaining L″, R″ and C″, and feeding them to the left and right full-range speakers and the high-frequency center speaker respectively, the left surround speaker in the θ_LS direction can be virtualized. And the three functions of A, B and D is related to the virtual surround speaker direction θ_LS to be produced. In fact, formula (9) is equivalent to combining steps such as frequency division, two-speaker and three-speaker virtual processing, and signal mixing in Fig. 4 .Since the system in Fig. 4 is a linear system, this is obviously feasible.

用类似的方法，只要将输入的右环绕通路信号RS₀分别与A(θ_RS，ω)、B(θ_RS，ω)、D(θ_RS，ω)三个函数进行频域相乘后可得到L″、R″和C″，将它们分别馈给左、右全频带扬声器和高频中置扬声器后，即可虚拟出θ_RS方向的右环绕扬声器。而A、B、C三个函数只要在(7)式方括号内的量中，将H_lLS、H_rLS换为H_lRS、H_rRS(布置在θ＝θ_RS方向的右环绕扬声器到双耳的频域传输函数)即可。In a similar way, as long as the input right surround channel signal RS₀ is multiplied by the three functions A(θ_RS , ω), B(θ_RS , ω), and D(θ_RS , ω) in the frequency domain, the After obtaining L″, R″ and C″, and feeding them to the left and right full-range speakers and the high-frequency center speaker respectively, the right surround speaker in the θ_RS direction can be virtualized. And the three functions of A, B and C Just replace H_lLS , H_rLS with H_lRS , H_rRS (the frequency domain transfer function from the right surround speaker arranged in the direction θ=θ_RS to binaural) in the quantities in the square brackets in formula (7).

至于虚拟环绕扬声器布置角度θ_LS、θ_RS的选择，由于在虚拟重发中，利用前半平面的扬声器布置是不可能产生稳定的后半平面声像的，后半平面声像会出现在前半平面的镜像位置上。作为一种妥协的方法，本发明为确保前半平面±90°范围内的声像，将两个环绕扬声器虚拟在±90°的方向而不是±110°方向上。事实上，按Dolby实验室的标准，在实际的5.1通路环绕声重发中，当房间条件受到限制时，是可以将两个环绕扬声器前移到±90°的方向的。As for the choice of virtual surround speaker arrangement angles θ_LS and θ_RS , in virtual retransmission, it is impossible to produce a stable sound image in the rear half plane by using the speaker arrangement in the front half plane, and the sound image in the rear half plane will appear in the front half plane on the mirrored position. As a compromise method, in order to ensure the sound image within the ±90° range of the front half plane, the present invention virtualizes the two surround speakers in the direction of ±90° instead of ±110°. In fact, according to the standard of Dolby laboratory, in the actual 5.1 channel surround sound reproduction, when the room conditions are limited, it is possible to move the two surround speakers forward to the direction of ±90°.

但是(9)式的信号处理是和频率有关的，因而会引起重发的音色改变。为了减少重发中音色的改变，本发明还引入了对音色进行重新均衡的信号处理。由于在立体声的扬声器重发中，声像位置只是由通路信号间的相对振幅和相对相位所决定的，各通路的信号同时乘(除)以一个频率的函数并没有改变信号的相对振幅和相位关系，因而不会引起虚拟声像位置的改变。但这种处理改变了系统输出的总功率谱，因而就改变了音色。可利用这种方法对音色进行重新均衡。以左环绕通路信号LS₀为例，在(9)式的信号处理中，如果各式同时除以一个因子(|A|²+|B|²+|D|²)^1/2，则可得到经过均衡后的重发信号：L″＝A′(θ_LS，ω)LS₀  R″＝B′(θ_LS，ω)LS₀  C″＝D′(θ_LS，ω)LS₀  (10)其中：                                (11)But the signal processing of formula (9) is frequency-dependent, which will cause the timbre change of retransmission. In order to reduce the change of timbre during retransmission, the present invention also introduces signal processing for re-balancing the timbre. Since in stereo loudspeaker reproduction, the sound image position is only determined by the relative amplitude and relative phase between the channel signals, the simultaneous multiplication (division) of the signals of each channel by a function of frequency does not change the relative amplitude and phase of the signal Therefore, it will not cause changes in the position of the virtual sound image. But this processing changes the overall power spectrum of the system's output, and thus the timbre. This method can be used to re-equalize the sound. Taking the left surround channel signal LS₀ as an example, in the signal processing of formula (9), if all formulas are divided by a factor (|A|² +|B|² +|D|² )^1/2 at the same time, then Obtain the equalized retransmission signal: L″=A′(θ_LS , ω)LS₀ R″=B′(θ_LS ,ω)LS₀ C″=D′(θ_LS ,ω)LS₀ (10 ) of which: (11)

${\mathrm{<span><span>A</span>A</span>}}^{<span><span>\&prime;</span>\&prime;</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>=</span>=</span>\frac{\mathrm{<span><span>A</span>A</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span>}{\sqrt{{<span><span>|</span>|</span>\mathrm{<span><span>A</span>A</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}<span><span>+</span>+</span>{<span><span>|</span>|</span>\mathrm{<span><span>B</span>B</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}<span><span>+</span>+</span>{<span><span>|</span>|</span>\mathrm{<span><span>D</span>D.</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}}}$

${\mathrm{<span><span>B</span>B</span>}}^{<span><span>\&prime;</span>\&prime;</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>=</span>=</span>\frac{\mathrm{<span><span>B</span>B</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span>}{\sqrt{{<span><span>|</span>|</span>\mathrm{<span><span>A</span>A</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}<span><span>+</span>+</span>{<span><span>|</span>|</span>\mathrm{<span><span>B</span>B</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}<span><span>+</span>+</span>{<span><span>|</span>|</span>\mathrm{<span><span>D</span>D.</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}}}$

${\mathrm{<span><span>D</span>D.</span>}}^{<span><span>\&prime;</span>\&prime;</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>=</span>=</span>\frac{\mathrm{<span><span>D</span>D.</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span>}{\sqrt{{<span><span>|</span>|</span>\mathrm{<span><span>A</span>A</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}<span><span>+</span>+</span>{<span><span>|</span>|</span>\mathrm{<span><span>B</span>B</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}<span><span>+</span>+</span>{<span><span>|</span>|</span>\mathrm{<span><span>D</span>D.</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>LS</span>LS</span>}}<span><span>,</span>,</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}<span><span>)</span>)</span><span><span>|</span>|</span>}^{\mathrm{<span><span>2</span>2</span>}}}}$

可以看出，(10)式的信号满足：It can be seen that the signal of (10) satisfies:

|L″|²+|R″|²+|C″|²＝|LS₀|²                              (12)所以经过均衡后，各通路信号的总功率将等于或正比于原始左环绕通路信号LS₀的功率|LS₀|²，而信号处理不会引起音色的改变。|L″|² +|R″|² +|C″|² ＝|LS₀ |² (12) So after equalization, the total power of each channel signal will be equal to or proportional to the original left surround channel signal LS₀ Power |LS₀ |² , and signal processing does not cause a change in timbre.

类似地，也可对右环绕通路信号RS₀的信号处理进行音色均衡。只要在(10)和(11)式中，将参数θ_LS换为θ_RS即可。Similarly, timbre equalization can also be performed on the signal processing of the right surround channel signal RS₀ . Just change the parameter θ_LS to θ_RS in (10) and (11).

图7是本发明的信号处理流程和扬声器布置图。本发明可以利用通用的信号处理芯片所做成的硬件电路实现，也可以设计成专用的集成电路芯片实现，还可以设计成软件在多媒体计算机上实现。本发明可用于DVD、电视、家庭影院、多媒体计算机等方面。Fig. 7 is a flow chart of signal processing and loudspeaker arrangement of the present invention. The present invention can be realized by using a hardware circuit made of a general signal processing chip, can also be designed as a special integrated circuit chip, and can also be designed as software to be realized on a multimedia computer. The invention can be used in DVD, TV, home theater, multimedia computer and the like.

实施例一 DVD与电视的应用Embodiment 1 Application of DVD and TV

将DVD解码输出或从数字电视广播得到的5.1通路环绕声(数字)信号按图7的方法进行虚拟处理后，得到三路信号L″、R″和C″，然后分别馈给一对前方±30°的全频带扬声器和一个布置在正前方(电视机上方)的高频中置扬声器，重发出环绕声的效果。其中，虚拟信号处理可作为DVD机内的一部分硬件电路，也可作为电视机的一部分硬件电路。After the 5.1-channel surround sound (digital) signal obtained from DVD decoding or digital TV broadcasting is virtual processed according to the method shown in Figure 7, three-way signals L", R" and C" are obtained, and then fed to a pair of front ± The 30° full-band speaker and a high-frequency center speaker arranged in the front (above the TV) reproduce the effect of surround sound. Among them, the virtual signal processing can be used as a part of the hardware circuit in the DVD player, or as a TV Part of the hardware circuit of the machine.

实施例二  家庭影院的应用Embodiment 2 Application of home theater

将DVD解码输出的5.1通路环绕声(数字)信号馈给家庭影院的放大器，图7的虚拟信号处理是作为放大器内的一部分功能电路。得到三路信号L″、R″和C″，然后分别馈给外接的全频带左、右和高频中置扬声器进行重发。The 5.1-channel surround sound (digital) signal output by DVD decoding is fed to the amplifier of the home theater, and the virtual signal processing in Figure 7 is used as a part of the functional circuit in the amplifier. The three-way signals L", R" and C" are obtained, and then respectively fed to the external full-band left, right and high-frequency center speakers for retransmission.

实施例三  多媒体计算机的应用Embodiment 3 Application of multimedia computer

由计算机的DVD-ROM读取，并经解码得到5.1通路环绕声(数字)信号，然后用计算机软件实行图7的虚拟信号处理，也可以在计算机的声卡上用专用的硬件电路实现，得到三路信号L″、R″和C″，由声卡输出到外接的全频带左、右和高频中置扬声器进行重发。It is read by the DVD-ROM of the computer and decoded to obtain the 5.1-channel surround sound (digital) signal, and then the virtual signal processing in Fig. 7 is implemented with computer software, or it can be realized with a dedicated hardware circuit on the sound card of the computer to obtain three The signals L", R" and C" of the channels are output by the sound card to the external full-band left, right and high-frequency center speakers for retransmission.

本发明具体介绍用软件在多媒体计算机上的实现：信号处理所用的头相关传输函数HRTF可通过理论计算或实验测量得到，这里所用的HRTF函数采样频率为是44.1kHz，长度512点(也可以是256点或128点)，分辨率16bit，自由场均衡。The present invention specifically introduces the realization of using software on a multimedia computer: the used head-related transfer function HRTF of signal processing can be obtained by theoretical calculation or experimental measurement, and the HRTF function sampling frequency used here is 44.1kHz, and length 512 points (also can be 256 points or 128 points), resolution 16bit, free field equalization.

图8是信号处理软件的流程图，信号处理过程就是(从DVD-ROM或硬盘)读入原始的5.1通路环绕声信号，在对它进行虚拟处理后，馈给扬声器重发。假定5.1通路环绕声的原始信号是时域的数字信号：Fig. 8 is a flow chart of the signal processing software. The signal processing process is to read in the original 5.1 channel surround sound signal (from DVD-ROM or hard disk), and after performing virtual processing on it, feed it to the speaker for retransmission. Assume that the original signal of the 5.1-channel surround sound is a digital signal in the time domain:

第一步：在DVD-ROM中读入原始的5.1通路时域信号，记为l₀、r₀、c₀、ls₀、rs₀、lfe₀。Step 1: Read the original 5.1-channel time-domain signals into the DVD-ROM, denoted as l₀ , r₀ , c₀ , ls₀ , rs₀ , lfe₀ .

第二步：利用FFT算法将5.1通路时域信号转换为原始的频域信号：左通路信号L₀、右通路信号R₀、中心通路信号C₀、左环绕通路信号LS₀、右环绕通路信号RS₀、低频效果通路信号LFE₀，并存入缓存器。Step 2: Use the FFT algorithm to convert the 5.1 channel time domain signal into the original frequency domain signal: left channel signal L₀ , right channel signal R₀ , center channel signal C₀ , left surround channel signal LS₀ , right surround channel signal RS₀ , low-frequency effect path signal LFE₀ , and stored in the register.

第三步：将原始的中心通路信号C₀与高通滤波器的传输函数H_HP相乘，得到H_HP C₀；将原始的中心通路信号C₀与低通滤波器的传输函数H_LP相乘，并乘0.707，得到0.707 H_LP C₀。Step 3: Multiply the original central channel signal C₀ with the transfer function H_HP of the high-pass filter to obtain H_HP C₀ ; multiply the original central channel signal C₀ with the transfer function H_LP of the low-pass filter , and multiply by 0.707 to get 0.707 H_LP C₀ .

第四步：将原始的低频效果通路信号LFE₀乘0.707，得到0.707 LFE₀。Step 4: Multiply the original low-frequency effect channel signal LFE₀ by 0.707 to obtain 0.707 LFE₀ .

第五步：将原始的左环绕通路信号LS₀分别与频域函数A’(90°，ω)、B’(90°，ω)、D’(90°，ω)进行相乘，得到A’(90°，ω)LS₀、B’(90°，ω)LS₀、D’(90°，ω)LS₀。Step 5: Multiply the original left surround channel signal LS₀ with the frequency domain functions A'(90°, ω), B'(90°, ω), D'(90°, ω) to obtain A '(90°, ω)LS₀ , B'(90°, ω)LS₀ , D'(90°, ω)LS₀ .

第六步：将原始的右环绕通路信号RS₀分别与频域函数A’(-90°，ω)、B’(-90°，ω)、D’(-90°，ω)进行频域相乘，得到A’(-90°，ω)RS₀、B’(90°，ω)RS₀、D’(90°，ω)RS₀。Step 6: The original right surround channel signal RS₀ and the frequency domain functions A'(-90°, ω), B'(-90°, ω), D'(-90°, ω) respectively in the frequency domain Multiply to get A'(-90°, ω)RS₀ , B'(90°, ω)RS₀ , D'(90°, ω)RS₀ .

第七步：将左通路信号L₀、0.707 H_LPC₀、A’(90°，ω)LS₀、A’(-90°，ω)RS₀、0.707 LFE₀相加，得到L″。Step 7: Add the left channel signal L₀ , 0.707 H_LP C₀ , A'(90°, ω)LS₀ , A'(-90°, ω)RS₀ , and 0.707 LFE₀ to obtain L″.

第八步：右通路信号R₀、0.707 H_LPC₀、B’(90°，ω)LS₀、B’(-90°，ω)RS₀、0.707 LFE₀相加，得到R″。Step 8: Add the right channel signal R₀ , 0.707 H_LP C₀ , B'(90°, ω)LS₀ , B'(-90°, ω)RS₀ , and 0.707 LFE₀ to obtain R″.

第九步：将H_HPC₀、D’(90°，ω)LS₀、D’(-90°，ω)RS₀相加，得到C″。Step 9: Add H_HP C₀ , D'(90°, ω)LS₀ , D'(-90°, ω)RS₀ to get C″.

第十步：将L″、R″、C″三个信号分别用IFFT变换到时域，并经D/A变换为模拟信号，馈给扬声器。Step 10: Transform the three signals of L", R", and C" into the time domain by IFFT respectively, and convert them into analog signals through D/A, and feed them to the speaker.

如上所述，即可较好地实现本发明。As described above, the present invention can be preferably realized.

用声像定位实验验证本发明的实际效果。用软件(Cooledit Pro 1.2)在计算机声频工作站中产生原始的5.1通路信号，信号采样频率为44.1kHz，量化精度为16bit，并存在硬盘上。由于在原始的5.1通路系统中，信号是通过分立一对的方法馈给扬声器的，也就是将信号只馈给某一扬声器而其它扬声器的信号为零，利用单一扬声器产生其方向上的声像。而将信号(同相位)馈给一对相邻的扬声器，利用信号的声级差产生这对扬声器之间的声像。例如将信号馈给图5的前方C₀扬声器(0°)和L₀扬声器(30°)，而其它扬声器信号为零，通过调节中心通路信号C₀和左通路信号L₀的振幅比(声级差)，就可以得到这对扬声器之间的声像。因此，在本发明中也是按分立--对的方法产生具有不同的通路声级差的原始5.1通路信号。The actual effect of the present invention is verified by sound image localization experiment. Use software (Cooledit Pro 1.2) to generate the original 5.1 channel signal in the computer audio frequency workstation, the signal sampling frequency is 44.1kHz, the quantization precision is 16bit, and it is stored on the hard disk. Since in the original 5.1 channel system, the signal is fed to the speaker through a separate pair, that is, the signal is only fed to a certain speaker and the signal of the other speaker is zero, and a single speaker is used to generate the sound image in its direction. . Instead, the signal (in phase) is fed to a pair of adjacent speakers, and the sound level difference between the signals is used to generate the sound image between the pair of speakers. For example, if the signal is fed to the front C₀ loudspeaker (0°) and L₀ loudspeaker (30°) in Fig. 5, while the other loudspeaker signals are zero, by adjusting the amplitude ratio of the center path signal C₀ and the left path signal L₀ (acoustic level difference), you can get the sound image between the pair of speakers. Therefore, also in the present invention, original 5.1 channel signals with different channel sound level differences are generated in a discrete-pair manner.

将原始的5.1通路信号按图7进行虚拟信号处理后，馈给左、右和高频中置三个真实扬声器进行重发。实验在一混响时间为0.15s的听音室内进行，扬声器布置在半径为2.0m的圆周上，其中左、右扬声器布置张角分别取±15°和±30°两种情况。信号处理所用的HRTF采用的刚球模型计算所得的数据。而高通和低通滤波器的分频点f₀＝300Hz。实验所用的是语言信号(普通话男声)，信号时间长度为20秒。After the original 5.1 channel signal is subjected to virtual signal processing according to Figure 7, it is fed to the left, right and high-frequency center three real speakers for retransmission. The experiment was carried out in a listening room with a reverberation time of 0.15s. The loudspeakers were arranged on a circle with a radius of 2.0m, and the opening angles of the left and right loudspeakers were respectively ±15° and ±30°. The data calculated by the rigid sphere model adopted by HRTF used in signal processing. And the frequency division point f₀ of the high-pass and low-pass filters is 300Hz. The language signal (Mandarin male voice) used in the experiment, the signal duration is 20 seconds.

实验时，让倾听者判断具有不同的通路声级差的5.1原始通路信号在虚拟重发时的声像位置，取八名倾听者的平均值作为最后的实验结果，并算出相应的均方差σ。During the experiment, listeners were asked to judge the sound image positions of the 5.1 original channel signals with different channel sound level differences during virtual retransmission, and the average value of eight listeners was taken as the final experimental result, and the corresponding mean square error σ was calculated.

由于重发虚拟声的左、右全频带扬声器的位置与原始的5.1通路系统的标准完全一致(见(1)式)，并不需要虚拟的方法。因而对于前方(0°≤θ_I≤30°)声像，是由两个±30°真实扬声器和一个正前方(0°)的高频(真实)扬声器产生，其原理和普通的声级差型立体声类似，并且过去研究已有相应的实验结果，在此就不再重复。Since the positions of the left and right full-band speakers that reproduce the virtual sound are completely consistent with the standard of the original 5.1 channel system (see (1) formula), a virtual method is not needed. Therefore, for the front (0°≤θ_I ≤30°) sound image, it is produced by two ±30° real speakers and a high-frequency (real) speaker directly in front (0°), and its principle is the same as that of the ordinary sound level difference type Stereo is similar, and the corresponding experimental results have been studied in the past, so I will not repeat them here.

5.1通路环绕声的侧向声像是通过左通路和左环绕通路产生的，在原始的5.1通路信号中，左通路信号L₀、左环绕通路信号LS₀不为零，而其他通路的信号R₀＝C₀＝RS₀＝0。而对虚拟重发的情况，侧向声像是由位于30°的真实扬声器和90°的虚拟扬声器共同产生。通过调节原始通路信号的声级差d＝20log(LS₀/L₀)(dB)，可产生不同方向的侧向声像。图9是声像定位的实验结果图，它给出了虚拟重发的侧向声像方向θ_I的实验值和均方差。为比较，图9中还给出了用以下的多通路环绕声声像定位公式计算所得到的，把左通路信号L₀、左环绕通路信号LS₀馈给假设布置于30°和90°扬声器的声像位置的理论值。The lateral sound image of the 5.1 channel surround sound is generated through the left channel and the left surround channel. In the original 5.1 channel signal, the left channel signal L₀ and the left surround channel signal LS₀ are not zero, while the signals of other channels R₀ =C₀ =RS₀ =0. In the case of virtual retransmission, the lateral sound image is jointly produced by the real loudspeaker at 30° and the virtual loudspeaker at 90°. By adjusting the sound level difference d=20log(LS₀ /L₀ )(dB) of the original channel signal, lateral sound images in different directions can be generated. Fig. 9 is a diagram of the experimental results of the sound image localization, which shows the experimental value and mean square error of the lateral sound image direction θ_I of the virtual retransmission. For comparison, Fig. 9 also shows the calculation obtained by using the following multi-channel surround sound image localization formula. The left channel signal L₀ and the left surround channel signal LS₀ are fed to the speakers that are assumed to be arranged at 30° and 90° The theoretical value of the panning position of .

$\mathrm{<span><span>sin</span>sin</span>}{\mathrm{<span><span>\&theta;</span>\&theta;</span>}}_{\mathrm{<span><span>I</span>I</span>}}<span><span>=</span>=</span>\frac{\mathrm{<span><span>0.5</span>0.5</span>}{\mathrm{<span><span>L</span><figure-callout\; label="L"\; filenames="A20041002806200201.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>+</span>+</span>{\mathrm{<span><span>LS</span>LS</span>}}_{\mathrm{<span><span>0</span>0</span>}}}{{\mathrm{<span><span>L</span><figure-callout\; label="L"\; filenames="A20041002806200201.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span><span>0</span>0</span>}}<span><span>+</span>+</span>{\mathrm{<span><span>LS</span>LS</span>}}_{\mathrm{<span><span>0</span>0</span>}}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>13</span>13</span>}<span><span>)</span>)</span>$

由图9可以看出，在原始通路信号声级差d＝20log(LS₀/L₀)由-24dB变化到24dB的过程中，声像位置的实验值和(13)式的理论值(理想值)的变化趋势是一致的(当d由-∞dB连续变化到+∞dB时，θ_I的理论值由+30°连续变化到+90°)，但数值上有一定的差别。特别是侧向声像，实验值较理论值向前方偏移。例如，对d＝24dB，θ_I的理论值为76.2°，实验值为64.0°。侧向声像位置畸变主要是由实际的倾听者的头部尺寸与虚拟声信号处理所用头部模型的尺寸的差别引起的。It can be seen from Fig. 9 that during the process of changing the sound level difference d=20log(LS₀ /L₀ ) of the original channel signal from -24dB to 24dB, the experimental value of the sound image position and the theoretical value (ideal value) of formula (13) ) is consistent (when d changes continuously from -∞dB to +∞dB, the theoretical value of θ_I changes continuously from +30° to +90°), but there is a certain difference in value. Especially the lateral sound image, the experimental value is shifted forward compared with the theoretical value. For example, for d=24dB, the theoretical value of θ_I is 76.2° and the experimental value is 64.0°. The lateral sound image position distortion is mainly caused by the difference between the actual listener's head size and the head model used for virtual acoustic signal processing.

对真正的5.1通路环绕声重发，后方声像是通过布置在±110°左、右环绕扬声器产生。但在虚拟重发中，布置在前半平面的真实扬声器是不能产生稳定的后半平面的声像的。事实上，在真正的5.1通路环绕声重发中，如果将两个环绕扬声器布置在±90°的方向上，也不能产生稳定的后半平面声像。因此这里没有给出虚拟重发时后方声像的定位结果。For true 5.1-channel surround sound reproduction, the rear sound image is generated by the left and right surround speakers arranged at ±110°. But in virtual retransmission, real loudspeakers arranged in the front half plane cannot produce a stable rear half plane sound image. In fact, in the true 5.1-channel surround sound reproduction, if two surround speakers are arranged in the direction of ±90°, a stable rear half-plane sound image cannot be produced. Therefore, the positioning results of the rear sound image during virtual retransmission are not given here.

本发明用前方一对真实的左、右全频带扬声器和一个高频中置扬声器进行重发，可产生整个前半平面的环绕声效果，从而达到节省重发扬声器的目的；另外本发明将重发虚拟环绕声的一对左、右全频带扬声器布置在±30°的位置，并采用高频中置扬声器，该布置可扩大听音区域，方便于实际应用，信号处理也简单可行，并且与普通的双通路立体声的扬声器布置兼容，这种新的扬声器布置特别适用于电视和多媒体计算机的应用。In the present invention, a pair of real left and right full-band speakers and a high-frequency center speaker are used for retransmission, which can produce the surround sound effect of the entire front half plane, thereby achieving the purpose of saving retransmission speakers; in addition, the present invention will retransmit A pair of left and right full-range speakers of the virtual surround sound are arranged at a position of ±30°, and a high-frequency center speaker is used. This arrangement can expand the listening area and is convenient for practical application. The signal processing is also simple and feasible, and it is different from ordinary Compatible with the two-way stereo speaker arrangement, this new speaker arrangement is especially suitable for TV and multimedia computer applications.

本发明的研究得到《国家自然科学基金，编号：10374031》的资助。The research of the present invention is funded by the National Natural Science Foundation of China, No. 10374031.

Claims (3)

Translated fromChinese

1.一种三扬声器虚拟5.1通路环绕声的信号处理方法，其特征是，包括如下步骤：1. a signal processing method of virtual 5.1 path surround sound of three loudspeakers, is characterized in that, comprises the steps:第一步：输入原始的5.1通路信号：左通路信号L₀、右通路信号R₀、中心通路信号C₀、左环绕通路信号LS₀、右环绕通路信号RS₀、低频效果通路信号LFE₀；Step 1: Input the original 5.1 channel signals: left channel signal L₀ , right channel signal R₀ , center channel signal C₀ , left surround channel signal LS₀ , right surround channel signal RS₀ , low frequency effect channel signal LFE₀ ;第二步：将原始的左、右通路信号L₀、R₀分别直接馈到左、右全频带扬声器的信号混合器；Step 2: Feed the original left and right channel signals L₀ and R₀ directly to the signal mixer of the left and right full-band speakers respectively;第三步：将原始的中心通路信号C₀经传输函数为H_HP的高通滤波后馈到高频中置扬声器的信号混合器，以直接产生高频的前方声像；中心通路信号C₀经过传输函数为H_LP的低通滤波和-3dB衰减后，同时馈给左、右全频带扬声器的信号混合器，以合成低频的前方声像；Step 3: Feed the original center channel signal C₀ to the signal mixer of the high-frequency center speaker after high-pass filtering with the transfer function H_HP , so as to directly generate the high-frequency front sound image; the center channel signal C₀ passes through After the transfer function is_HLP low-pass filtering and -3dB attenuation, it is fed to the signal mixer of the left and right full-range speakers at the same time to synthesize the low-frequency front sound image;第四步：原始的左环绕通路信号LS₀经过虚拟处理，得到三个信号A’(90°，ω)LS₀、B’(90°，ω)LS₀、D’(90°，ω)LS₀，然后分别馈到左、右全频带扬声器和高频中置扬声器的信号混合器，虚拟出90°方向的左环绕扬声器；Step 4: The original left surround channel signal LS₀ undergoes virtual processing to obtain three signals A'(90°,ω)LS₀ , B'(90°,ω)LS₀ ,D'(90°,ω) LS₀ , then fed to the signal mixer of the left and right full-range speakers and the high-frequency center speaker respectively, virtualizing the left surround speaker in a 90° direction;第五步：原始的右环绕通路信号RS₀经过虚拟处理，得到三个信号A’(-90°，ω)RS₀、B’(-90°，ω)RS₀、D’(-90°，ω)RS₀，然后分别馈到左、右全频带扬声器和高频中置扬声器的信号混合器，虚拟出-90°方向的右环绕扬声器；Step 5: The original right surround channel signal RS₀ undergoes virtual processing to obtain three signals A'(-90°, ω)RS₀ , B'(-90°, ω)RS₀ , D'(-90° , ω)RS₀ , and then respectively fed to the signal mixer of the left and right full-range speakers and the high-frequency center speaker, virtualizing the right surround speaker in the -90° direction;第六步：原始的低频效果通路信号LFE₀经-3dB衰减后，同时馈给左、右全频带扬声器的信号混合器；Step 6: After the original low-frequency effect channel signal LFE₀ is attenuated by -3dB, it is simultaneously fed to the signal mixer of the left and right full-band speakers;第七步：分别对馈给左、右全频带扬声器和高频中置扬声器的输入信号进行混合，得到L″、R″、C″三个信号，然后分别馈给布置在±30°的左、右全频带扬声器和0°的高频中置扬声器重发。Step 7: Mix the input signals fed to the left and right full-range speakers and the high-frequency center speaker respectively to obtain three signals of L", R", and C", and then feed them to the left , the right full-range speaker and the high-frequency center speaker at 0°.2.根据权利要求1所述的三扬声器虚拟5.1通路环绕声的信号处理方法，其特征是，第四步中对原始的左环绕通路信号LS₀的虚拟处理，就是将左环绕通路信号LS₀分别与三个从水平面90°头相关传输函数得到的函数A’(90°，ω)、B’(90°，ω)、D’(90°，ω)进行频域相乘。2. The signal processing method of the virtual 5.1 path surround sound of three loudspeakers according to claim 1, characterized in that, in the fourth step, the virtual processing of the original left surround path signal LS₀ is to make the left surround path signal LS₀ Multiply with three functions A'(90°, ω), B'(90°, ω), and D'(90°, ω) obtained from the 90° head-related transfer function in the horizontal plane, respectively, in the frequency domain.3.根据权利要求1所述的三扬声器虚拟5.1通路环绕声的信号处理方法，其特征是，第五步中对原始的右环绕通路信号RS₀的虚拟处理，就是将原始的右环绕通路信号RS₀分别与三个从水平面-90°头相关传输函数得到的函数A’(-90°，ω)、B’(-90°，ω)、  D’(-90°，ω)进行频域相乘。3. The signal processing method of the virtual 5.1 path surround sound of three loudspeakers according to claim 1, characterized in that, in the fifth step, the virtual processing of the original right surround path signal RS₀ is to convert the original right surround path signal RS₀ is performed in the frequency domain with three functions A'(-90°, ω), B'(-90°, ω), and D'(-90°, ω) obtained from the -90° head-related transfer function in the horizontal plane, respectively. multiplied.

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