CN103037301A - Convenient adjustment method for restoring range information of acoustic images - Google Patents

Abstract

A portable adjustment method for audio image distance information recovery, downmixing the m -channel speaker system to the original n -channel speaker system ( m > n , m ≥ 3); lossless related parameters obtained from the m -channel speaker system signal Transfer to the initial n- channel speaker system to measure relevant parameters in the initial n -channel speaker system; establish a model for changing the initial n- channel speaker system to a new n -channel speaker system to ensure the accuracy of the new n -channel speaker system The distance between the reconstructed sound image and the listening point and the distance between the original sound source and the listening point of the m -channel loudspeaker system remain unchanged; the objective function is selected based on the minimum number of adjustment channels; the model is solved; according to the solution of the model Adjust the speaker signal. The invention ensures that the distance between the reconstructed sound image and the listening point in the new n -channel system is consistent with the distance between the original sound source and the listening point of the m- channel loudspeaker system, and the loudspeaker signal can be configured conveniently and quickly.

Description

Portable adjustment method for restoring acoustic image distance information

Technical Field

The invention belongs to the field of acoustics, and particularly relates to a portable adjustment method for restoring acoustic image distance information.

Background

5.1 multichannel systems were once a very popular home cinema sound system. However, with the development of 3D video technology, higher requirements are put on audio technology, and now multichannel audio research is focused on more advanced systems with more channels, which can provide people with better immersion. For example, the 22.2 multichannel system of japan broadcasting association laboratories has been used for ultra high definition television distribution. This advanced multi-channel system requires that the speakers be placed according to their own unique speaker placement method to produce the best sound results. Although 24 speakers can be placed in the theater in an optimal way, placement is cumbersome for home use. "downmix" is a good way of reducing the loudspeaker channels in a multi-channel system. Downmix from 5.1 to two-channel stereo or mono has been standardized in ITU-R Recommendation and is used for some television receivers. Although this downmixing method is very efficient, it is not applicable to any number of speaker configurations. In order to make the down-mixing between multiple systems feasible, a new sound field reconstruction or transformation technique is urgently needed. AkioAndo of the Japan broadcast Association laboratory in 2011 proposes a new downmix method, which utilizes a transformation matrix to transform loudspeaker signals of an original sound field into loudspeaker signals of a reconstructed sound field and ensures that the physical properties of sound of the original sound field and the reconstructed sound field at a listening point are consistent. The solution to this problem is frequency dependent, indicating that this transformation does not change the timbre. The physical property utilized by the user is unchanged, namely the sound pressure and the particle velocity direction of the sound at the listening point are unchanged before and after the change. Akio Ando also uses his method to reduce the 22.2 multi-channel system to 10.2 and 8.2 multi-channel systems. After the solution is solved by using the Akio Ando, people can find that the energy of the loudspeaker signal in the original sound field is not equal to the energy of the loudspeaker signal in the reconstructed sound field and contradicts with the law of energy conservation, which indicates that the distance information is damaged in the downmixing method of the Akio Ando. Therefore, the first problem to be solved at present is how to keep the physical properties of the sound at the receiving point unchanged and keep the distance information of the sound source in the original sound field from being damaged in the process of multichannel downmix.

Disclosure of Invention

The invention provides a portable adjustment method for restoring sound image distance information in a sound reproduction stage, aiming at the defects of the prior art.

The invention provides a portable adjustment method for restoring sound image distance information, which is characterized by comprising the following steps:

step 1, downmixing an m-channel loudspeaker system to obtain an n-channel loudspeaker system, recording the n-channel loudspeaker system obtained by downmixing as an initial n-channel loudspeaker system, wherein m is greater than n, and m is greater than or equal to 3;

step 2, obtaining and measuring relevant parameters, including obtaining the distance d from the original sound source of the m-channel loudspeaker system to the listening point₀Obtaining the sound pressure P of the listening point from the signal of the m-channel loudspeaker system₀And sound pressure P of left and right ears_L0、P_R0And the particle velocity V at the listening point₀And transmitted to the initial n-channel speaker system, where d₀、P_L0、P_R0、V₀All transmission is lossless; measuring the distance d of each loudspeaker from the listening point in the initial n-channel loudspeaker system_jMeasuring the distance d of each speaker from the left ear point in the initial n-channel speaker system_LjMeasuring the initial n channel speakerDistance d of each loudspeaker in the system from the right ear point_RjJ =1,2, … n; measuring the radius h of the human head;

step 3, converting the initial n-channel loudspeaker system signal into a new n-channel loudspeaker system signal to obtain an equation as follows;

$\left\{\begin{array}{c}{P}_0=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{{\mathrm{\ω}}_j{W}_j}{d_j^2}}\\ P_{L0}=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{{\mathrm{\ω}}_j{W}_j}{d_{\mathrm{Lj}}^2}}\\ P_{R0}=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{{\mathrm{\ω}}_j{W}_j}{d_{\mathrm{Rj}}^2}}\\ 2d^2=d_L^2+d_R^2-2h^2\\ V_0=G\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{e^{-\mathrm{ik}|\stackrel{\→}{0}-{\mathrm{\ρ}}^j|}}{|\stackrel{\→}{0}-{\mathrm{\ρ}}^j|}{\mathrm{\ω}}_j{S}_j\left(\mathrm{\ω}\right)\\ d_0=d\end{array}\right.$

representing the position vector of the listening point, and the polar coordinates are (0, 0, 0);

ρ^jrepresenting an initial n-channel loudspeaker systemThe distance between the position of the jth loudspeaker and the origin;

d represents the distance between the sound image generated by all the loudspeakers in the new n-channel loudspeaker system and the listening point;

d₀representing the distance between the original sound source of the m-channel loudspeaker system and a listening point;

S_j(ω) is the signal of the jth speaker in the initial n-channel speaker system;

π is the circumference ratio;

the coefficient G is an acoustic constant of the audio signal propagating in air;

V₀representing the particle velocity at the listening point in an m-channel loudspeaker system;

d_Lrepresenting the distance of the sound image generated by all the loudspeakers in the new n-channel loudspeaker system to the left ear;

d_Rrepresenting the distance of the sound image produced by all the loudspeakers in the new n-channel loudspeaker system to the right ear;

d_jrepresenting the distance of the jth loudspeaker in the initial n-channel loudspeaker system from the listening point;

d_Ljrepresenting the distance of the jth speaker to the left ear in the initial n-channel speaker system;

d_Rjrepresenting the distance from the jth speaker to the right ear in the initial n-channel speaker system;

W_jrepresenting the acoustic power of the jth loudspeaker in the initial n-channel loudspeaker system at the sound production point;

ω_jrepresenting a weighting factor adjusted for a jth speaker signal in the initial n-channel speaker system;

P₀representing sound pressure at a listening point in an m-channel speaker system;

P_L0representing the sound pressure at the left ear point in an m-channel speaker system;

P_R0representing the sound pressure at the right ear point in the m-channel loudspeaker system;

step 4, setting a target function, adding the following mapping function formula as a constraint condition into the equation obtained in the step 3 to obtain an optimized model M

$f\left({\mathrm{\ω}}_j\right)=\left\{\begin{array}{c}1,\left({\mathrm{\ω}}_j\right)\≠1\\ 0,{\mathrm{\ω}}_j=1\end{array}\right.$

The expression of the objective function is $M=\min \underset{i=1}{\overset{n}{\mathrm{\Σ}}}f\left({\mathrm{\ω}}_j\right);$

Step 5, solving the minimum value of the optimization model MObtaining the weight factor omega of each loudspeaker signal adjustment_j，j＝1,2,…n；

Step 6, obtaining the weight factor omega according to the solution in the step 5_jJ =1,2, … n, and the signals of the speakers in the initial n-channel speaker system are adjusted to obtain a new n-channel speaker system.

By adopting the loudspeaker placement structure and the signal distribution method, the sound pressure of the sound at the positions of the left and right ears L, R is ensured to be unchanged and the particle speed at the listening positions is ensured to be unchanged at the listening positions in the reconstructed sound field under the condition of adopting the same number of loudspeakers, and meanwhile, the distance information between the sound and the listening positions can be recovered, and the signals in the minimum number of sound channels are adjusted, so that the sound field can be reconstructed better and more conveniently.

Drawings

FIG. 1 is an overall framework flow diagram of an embodiment of the invention

Fig. 2 is a diagram of the placement of speakers in a 22.2 multi-channel system according to an embodiment of the present invention.

Fig. 3 is a diagram of a 10.2 multi-channel system speaker selection method according to an embodiment of the invention.

Fig. 4 is a diagram of the placement positions of speakers of a 10.2 multi-channel system according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of a 10.2 multi-channel system speaker of an embodiment of the present invention generating sound pressures at the left and right ears and sound images at the left and right ears.

Fig. 6 is a diagram showing the relationship between the sound image-to-listening point distance, the sound image-to-left and right ear distances, and the radius of the human head in a 10.2 multi-channel system according to an embodiment of the present invention.

Detailed Description

The technical scheme of the invention is explained in detail in the following by combining the drawings and the embodiment.

As shown in fig. 2 and 4, the embodiment takes m =22 and n =10, and the specific example of the embodiment is to use a 22.2 channel system to convert to a 10.2 channel system to describe the content of the invention. 22 loudspeakers in the 22.2 sound channel system are placed on the same spherical surface, 10 loudspeakers in the 10.2 sound channel system are placed on the same spherical surface, and the radius of the external spherical surface is 2 meters. In this embodiment, the 2 sound channels are two low-frequency sound effect sound channels, signals of the two low-frequency sound effect sound channels are not processed, and positions of the two low-frequency sound effect sound channels are not changed. The overall framework flow diagram of this embodiment is shown in fig. 1.

The embodiment adopts the sound image distance information recovery portable adjusting method, which comprises the following steps:

step 1, downmixing an m-channel loudspeaker system to obtain an n-channel loudspeaker system, recording the n-channel loudspeaker system obtained by downmixing as an initial n-channel loudspeaker system, wherein m is greater than n, and m is greater than or equal to 3.

The embodiment downmixes the 22.2 channel speaker system to the original 10.2 channel speaker system (denoted as the original 10.2 channel speaker system). The method adopted in the process is to keep the physical properties (sound pressure size and particle velocity direction) of the sound of the original sound field and the reconstructed sound field at the listening point (namely the center point of the human head) unchanged.

The implementation of step 1 comprises the following sub-steps,

step 1.1, a three-dimensional rectangular coordinate system XYZ is established, the origin is O, all the coordinates related to the invention are polar coordinates and are generally marked as P (sigma, theta, phi), wherein sigma, theta and phi respectively refer to the distance between the P point and the origin O, the included angle between the projection of the connecting line of the P point and the origin O on the X axis and the X axis, and the included angle between the connecting line of the P point and the origin O and the XOY plane, and the coordinates mentioned herein are explained with reference to the description. The 22 loudspeakers in the 22.2-channel loudspeaker system are arranged on the same spherical surface, see fig. 2, the specific position of each loudspeaker is fixed, and the coordinate xi of each loudspeaker is recorded^j＝(ρ_j,θ_j,φ_j) (j =1,2, … 22), and the listening point positions in this embodiment are all the sameAt the origin O;

as shown in fig. 2, in the embodiment, the center coordinates of the sphere are three-dimensional origin coordinates (0, 0, 0) and also coordinates at a listening point, and the coordinates of the 22 speakers are (2, 0 °,0 °), (2, 30 °,0 °), (2, 60 °,0 °), (2, 90 °,0 °), (2, 120 °,0 °), (2, 150 °,0 °), (2, 180 °,0 °), (2, 225 °,0 °), (2, 270 °,0 °), (2, 315 °,0 °), (2, 0 °, 48 °), (2, 45 °, 48 °), (2, 90 °, 48 °), (2, 135 °, 48 °), (2, 180 °, 48 °), (2, 225 °, 48 °), (2, 270 °, 48 °), (2, 0 °, 90 °), (2, 45 °, 30 °), (2, 90 °, -30 °), (2 °,135 °, -30 °) and

step 1.2, selecting the placing positions of 10 loudspeakers in an initial 10.2 loudspeaker sound channel system. The selection requirements are as follows: (1) selecting 1 speaker at a time in the 22.2 channel speaker system, the ray from the origin O to the direction of the point where each speaker of the 22.2 channel speaker system is located must be contained inside or on the side of the spherical triangle formed by the three speakers in the initial 10.2 channel speaker system, (2) while ensuring that the area of the spherical triangle formed by the three selected speakers in the initial 10.2 channel speaker system is the smallest of all alternatives. The positions of the 10 speakers in the initial 10.2 channel speaker system may be determined based on the positions of the 22 speakers in the 22.2 channel speaker system in accordance with the two-point requirements described above. After the position selection of the 10 speakers of the initial 10.2 channel speaker system is completed, the coordinates of the 10 speakers are recorded and recorded as

(j=1,2,…10）。

The method of selecting speakers of the initial 10.2 channel speaker system in this embodiment is shown in fig. 4, and the coordinates of the 10 speakers in the initial 10.2 channel system are recorded as (2, 0 °,0 °), (2, 60 °,0 °), (2, 120 °,0 °), (2, 180 °,0 °), (2, 270 °,0 °), (2, 0 °, 48 °), (2, 90 °, 48 °), (2, 180 °, 48 °), (2, 0 °, 90 °), (2, 90 °, and-30 °), respectively.

Step 1.3, the signals distributed by 10 loudspeakers in the initial 10.2-channel loudspeaker system are solved. First, the signal distribution coefficients for the three loudspeakers in the initial 10.2 channel system are found. In the actual operation process, the basis is to ensure that the sound pressure and the particle velocity direction of the sound generated by one loudspeaker in the 22.2-channel loudspeaker system at the listening point and the corresponding three loudspeakers in the initial 10.2-channel loudspeaker system at the listening point are unchanged, and one loudspeaker in the 22.2-channel system is placed at the zeta position, wherein the zeta position is set₁、ζ₂、ζ₃The three loudspeakers with the smallest area in the initial 10.2 channel loudspeaker system containing the zeta point are respectively arranged, see fig. 3, the spherical radius is r, and the signal of the virtual loudspeaker at the zeta point is distributed to the zeta point₁、ζ₂、ζ₃The distribution factors of the loudspeakers are respectively omega₁、ω₂、ω₃：

The formula is as follows:

wherein i is an imaginary unit, and e represents a mathematical constant, also called euler number;

ρ₁、ρ₂、ρ₃and rho is zeta₁、ζ₂、ζ₃Distance at ζ and origin O;

k is the number of waves,

f is the frequency of the sound, c is the speed of sound propagation in air;

θ₁、θ₂、θ₃and theta is zeta₁、ζ₂、ζ₃The line connecting zeta with the origin OThe included angle between the projection on the XOZ plane and the X axis;

are each ζ₁、ζ₂、ζ₃Angle between the line connecting ζ and origin O and XOY plane.

According to the analogy of the method, the distribution coefficient of each loudspeaker in the 22.2 sound channel loudspeaker system to 3 corresponding loudspeakers in the initial 10.2 sound channel loudspeaker system is obtained, then the signals repeatedly distributed by each loudspeaker in the 10 loudspeakers in the initial 10.2 sound channel loudspeaker system are superposed, and the signals of each loudspeaker in the initial 10.2 sound channel loudspeaker system are obtained, and 2 low-frequency sound effect loudspeaker signals are unchanged.

The distribution coefficients and the speaker signal calculations in this embodiment can be calculated by substituting the associated coordinates into the formula according to formula (1) and the above description. The present embodiment only describes that one method is selected for implementation of downmixing an m-channel speaker system to an initial n-channel speaker system, and the method for implementing the downmixing is not limited to the specific description of the embodiment.

And 2, acquiring and measuring the related parameters.

Keeping the positions of the loudspeakers unchanged, and adjusting the signals of the loudspeakers in the initial 10.2-channel loudspeaker system to obtain a new 10.2-channel loudspeaker system.

In the step, the distance between the original sound source and the listening point can be acquired from a signal acquisition sound field of the 22.2-channel loudspeaker system, and the distance between the original sound source and the listening point of the 22.2-channel loudspeaker system can also be acquired in other modes; obtaining sound pressure P of listening point from 22.2 sound channel loudspeaker system signal₀And sound pressure P of left and right ears_L0、P_R0And the particle velocity V at the listening point₀As a signal to an initial 10.2 channel loudspeaker system, where d₀，P_L0，P_R0，V₀All without loss of transmission, whichIn d₀Can be measured or obtained by other means, P_L0，P_R0，V₀May be calculated or measured. Measuring the distance d of each loudspeaker in an initial 10.2 channel loudspeaker system from the listening point_j(j =1,2, … 10), the distance d of each speaker from the left ear point in the initial 10.2 channel speaker system was measured_Lj(j =1,2, … 10), the distance d of each speaker from the right ear point in the initial 10.2 channel speaker system was measured_Rj(j =1,2, … 10), the radius of the head h is measured.

And 3, converting the initial n-channel loudspeaker system signal into a new n-channel loudspeaker system signal to obtain an equation.

In this embodiment the original 10.2 channel loudspeaker system signals are transformed to new 10.2 channel loudspeaker system signals. In the transformation process, the positions of the speakers of the new 10.2 channel speaker system and the old 10.2 channel speaker system are not changed, the sound pressures of the sound field of the 22.2 channel system and the sound of the reconstructed sound field at the listening point, the left ear and the right ear are kept unchanged, the particle velocity at the listening point is unchanged, and 2 low-frequency sound effect channels are not processed, as shown in fig. 4 and 5. 22.2 original sound source to listening point distance d of sound track loudspeaker system₀And the reconstructed sound image in the new 10.2 channel loudspeaker system is at the same distance from the listening point.

Namely, the positions of the speakers of the new and old n-channel speaker systems are not changed in the transformation process, but the sound pressure of the sound field of the 22.2-channel speaker system and the sound of the reconstructed sound field and the particle speed at the listening point are not changed at three points of the listening point and L, R, and the distance d between the original sound source of the 22.2-channel speaker system and the listening point₀And adjusting the loudspeaker signals on the premise of the same distance from the sound image reconstructed in the new n-channel system to the listening point.

The equation that can be derived from these requirements is:

$\left\{\begin{array}{c}{P}_0=P^{\′}\\ P_{L0}=P_{L0}^{\′}\\ P_{R0}=P_{R0}^{\′}\\ V_0=V^{\′}\\ d_0=d\end{array}\right.---\left(2\right)$

wherein,

p' is the sound pressure generated by all the loudspeakers in the new 10.2 channel loudspeaker system at the listening point;

P′_L0the sound pressure generated at the left ear for all speakers in the new 10.2 channel speaker system;

P′_R0the sound pressure generated at the right ear for all speakers in the new 10.2 channel speaker system;

v' is the particle velocity produced at the listening point by all loudspeakers in the new 10.2 channel loudspeaker system;

d is the distance between the sound image generated by all the loudspeakers in the new 10.2-channel loudspeaker system and the listening point;

P₀representing sound pressure at a listening point in a 22.2 channel speaker system;

P_L0representing the sound pressure at the left ear point in a 22.2 channel speaker system;

P_R0representing the sound pressure at the right ear point in a 22.2 channel loudspeaker system;

d₀representing the distance between the original sound source of a 22.2 channel loudspeaker system and a listening point;

V₀representing the particle velocity at the listening point in a 22.2 channel speaker system.

One loudspeaker provides a single point source whose sound pressure in the free field varies with the distance of the point from the source (assuming the environment is a free field, i.e. there is no reflection of sound):

$P_j=\sqrt{\frac{100}{\mathrm{\π}}\frac{W_j}{d_j^2}}$

（3）

wherein,

P_jthe sound pressure of a measuring point;

d_jthe distance between a point sound source and a measuring point is measured;

W_jis the sound power of the pointing sound source at the sound production point;

and pi means a circumferential ratio.

The variation of sound pressure of n point sound sources in a free field along with the distance between a measuring point and the sound source is as follows:

$P_j=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{W_j}{d_j^2}}---\left(4\right)$

wherein W_jRefers to the sound power of the j-th point sound source at the sound production point, j =1,2, … n. As in fig. 5, ω₁,ω₂,ω₃Is the signal distribution coefficient, W, of the three loudspeakers₁,W₂,W₃Refers to the acoustic power of the three speakers.

n coordinates are

j is 1,2, … n, inListening point

The particle velocity is:

$V=G\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{e^{-\mathrm{ik}|\stackrel{\→}{r}-{\mathrm{\ζ}}^j|}}{|\stackrel{\→}{r}-{\mathrm{\ζ}}^j|}{S}_j\left(\mathrm{\ω}\right)---\left(5\right)$

wherein,

S_j(ω) is the signal in the loudspeaker;

i is an imaginary unit;

k is the number of waves,

f is the frequency;

c is the speed of sound propagation in air;

the coefficient G is an acoustic constant of the audio signal propagating in the air.

As shown in fig. 6, due to the particularity of selecting two points L and R, the present implementation may also add a constraint condition to the model, i.e. the distance d between the sound image generated by all the speakers in the new 10.2 channel speaker system and the listening point, and the distance d between the sound image and the left and right ears_L、d_RThe relationship between the human head radius h is:

$2d^2=d_L^2+d_R^2-2h^2---\left(6\right)$

by collating the above equations (2), (3), (4), (5) and (6) and simplifying, the following equations can be obtained:

$\left\{\begin{array}{c}{P}_0=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{10}{\mathrm{\Σ}}}\frac{{\mathrm{\ω}}_j{W}_j}{d_j^2}}\\ P_{L0}=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{10}{\mathrm{\Σ}}}\frac{{\mathrm{\ω}}_j{W}_j}{d_{\mathrm{Lj}}^2}}\\ P_{R0}=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{10}{\mathrm{\Σ}}}\frac{{\mathrm{\ω}}_j{W}_j}{d_{\mathrm{Rj}}^2}}\\ 2d^2=d_L^2+d_R^2-2h^2\\ V_0=G\underset{j=1}{\overset{10}{\mathrm{\Σ}}}\frac{e^{-\mathrm{ik}|\stackrel{\→}{0}-{\mathrm{\ρ}}^j|}}{|\stackrel{\→}{0}-{\mathrm{\ρ}}^j|}{\mathrm{\ω}}_j{S}_j\left(\mathrm{\ω}\right)\\ d_0=d\end{array}\right.---\left(7\right)$

representing the position vector of the listening point, and the polar coordinates are (0, 0, 0);

ρ^jrepresenting the distance between the position of the jth loudspeaker in the initial 10.2-channel loudspeaker system and the origin;

d represents the distance of the sound image produced by all the loudspeakers in the new 10.2 channel loudspeaker system from the listening point;

d_Lrepresenting the distance of the sound image produced by all the loudspeakers in the new 10.2 channel loudspeaker system to the left ear;

d_Rshow newDistance of sound image generated by all speakers in the 10.2 channel speaker system to the right ear;

d_jrepresents the distance from the listening point of the jth loudspeaker in the initial 10.2-channel loudspeaker system, j being 1,2,3 … 10;

d_Ljrepresents the distance from the jth speaker to the left ear in the initial 10.2 channel speaker system, j =1,2,3 … 10;

d_Rjrepresents the distance from the jth loudspeaker to the right ear in the initial 10.2-channel loudspeaker system, j being 1,2,3 … 10;

W_jj =1,2,3 … 10, which represents the sound power of the jth speaker in the initial 10.2-channel speaker system at the sound generating point, and can be calculated by the signal input to the jth speaker in the initial 10.2-channel speaker system and the inherent power of the speaker;

ω_ja signal distribution coefficient representing the jth speaker, i.e. a weight factor adjusted to each speaker signal in the initial 10.2-channel speaker system, j =1,2,3 … 10;

P₀representing sound pressure at a listening point in a 22.2 channel speaker system;

P_L0representing the sound pressure at the left ear point in a 22.2 channel speaker system;

P_R0representing the sound pressure at the right ear point in a 22.2 channel loudspeaker system;

d₀representing the distance between the original sound source of a 22.2 channel loudspeaker system and a listening point;

S_j(ω) is the signal of the jth speaker in the initial 10.2 channel speaker system;

π is the circumference ratio;

the coefficient G is an acoustic constant of the audio signal propagating in air;

V₀representing 22.2 channel speaker systemsThe velocity of the particles at the listening point in the system.

And 4, selecting a target function. Because the number of the channels adopted in the multi-channel system is more, the placement is troublesome, the signal is convenient to adjust, and the use is convenient, the objective function adopted by the invention is the minimum number of the channels needing to be adjusted. Introducing a weighting factor omega for the adjustment_jA mapping function of:

$f\left({\mathrm{\ω}}_j\right)=\left\{\begin{array}{c}1,{\mathrm{\ω}}_j\≠1\\ 0,{\mathrm{\ω}}_j=1\end{array}\right.---\left(8\right)$

the mapping function is added as a constraint to equation (7). The target function expression is:

step 5, solving the minimum value of the optimization model M to obtain the weight factor omega of each loudspeaker signal adjustment_j. In this embodiment, the minimum value of the optimization model M after the objective function is added in step 4 is solved by using the optimization software Lingo, and the weight factor ω adjusted by each speaker signal is obtained_j，j=1,2,3…10。

And 6, adjusting the loudspeaker signal. In this embodiment, the weight factor ω obtained by solving in step 5 is used_j(j =1,2,3 … 10) adjusting the signals of the speakers in the original 10.2 channel system so that the distances between the reconstructed sound image and the listening point and the distances between the original sound source and the listening point of the 22.2 channel speaker system are equal, the channels needing to be adjusted are the least, and the aim is to adjust the multi-channel system as conveniently and quickly as possible besides ensuring that the sound pressures at the listening point, the L and the R point are constant and the particle speed at the center point is constant.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Claims (1)

1. A portable adjustment method for audio-visual distance information recovery, characterized in that, comprising steps: Step 1, down-mixing the m-channel speaker system to obtain an n-channel speaker system, and recording the down-mixed n-channel speaker system as the initial n-channel speaker system, m>n, and m≥3; Step 2, acquisition and measurement of relevant parameters, including obtaining the distance d ₀ from the original sound source of the m-channel speaker system to the listening point, obtaining the sound pressure P ₀ of the listening point and the left , right ear sound pressure P _L0 , P _R0 and particle velocity V ₀ at the listening point, and transmit to the initial n-channel speaker system, where d ₀ , P _L0 , P _R0 , V ₀ are all lossless transmission; measure the initial n The distance d _j between each speaker in the channel speaker system and the listening point, measure the distance d _Lj of each speaker in the initial n-channel speaker system from the left ear point, and measure the distance of each speaker in the initial n-channel speaker system to the right The distance d _Rj of the ear point, j=1,2,...n; measure the radius h of the human head; Step 3, transform the initial n-channel speaker system signal into a new n-channel speaker system signal, and obtain the equation as follows, $\left\{\begin{array}{c}{P}_0=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{\mathrm{no}}{\mathrm{\Σ}}}\frac{{\mathrm{\ω}}_j{W}_j}{d_j^2}}\\ P_{L0}=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{\mathrm{no}}{\mathrm{\Σ}}}\frac{{\mathrm{\ω}}_j{W}_j}{d_{\mathrm{Lj}}^2}}\\ P_{R0}=\sqrt{\frac{100}{\mathrm{\π}}\underset{j=1}{\overset{\mathrm{no}}{\mathrm{\Σ}}}\frac{{\mathrm{\ω}}_j{W}_j}{d_{\mathrm{Rj}}^2}}\\ 2d^2=d_L^2+d_R^2-2h^2\\ V_0=G\underset{j=1}{\overset{\mathrm{no}}{\mathrm{\Σ}}}\frac{e^{-\mathrm{ik}|\stackrel{\&Right\; Arrow;}{0}-{\mathrm{\ρ}}^j|}}{|\stackrel{\&Right\; Arrow;}{0}-{\mathrm{\ρ}}^j|}{\mathrm{\ω}}_j{S}_j\left(\mathrm{\ω}\right)\\ d_0=d\end{array}\right.$

Indicates the location vector of the listening point, and the polar coordinates are (0,0,0); ρ ^j represents the distance between the position of the jth speaker and the origin in the initial n-channel speaker system; d represents the distance between the sound image produced by all the speakers in the new n-channel speaker system and the listening point; d ₀ represents the distance between the original sound source of the m-channel speaker system and the listening point; S _j (ω) is the signal of the jth speaker in the initial n-channel speaker system; π refers to pi; The coefficient G is the acoustic constant of the audio signal propagating in the air; V ₀ represents the particle velocity at the listening point in the m-channel loudspeaker system; d _L represents the distance from the sound image produced by all the speakers in the new n-channel speaker system to the left ear; D _R represents the distance from the sound image produced by all the speakers in the new n-channel speaker system to the right ear; d _j represents the distance between the jth speaker and the listening point in the initial n-channel speaker system; d _Lj represents the distance from the jth speaker to the left ear in the initial n-channel speaker system; d _Rj represents the distance from the jth speaker to the right ear in the initial n-channel speaker system; W _j represents the sound power of the jth speaker at the sound point in the initial n-channel speaker system; ω _j represents the weighting factor adjusted to the jth speaker signal in the initial n-channel speaker system; P ₀ represents the sound pressure at the listening point in the m-channel speaker system; P _L0 represents the sound pressure at the left ear point in the m-channel speaker system; P _R0 represents the sound pressure at the right ear point in the m-channel speaker system; Step 4, set the objective function, add the following mapping function as a constraint to the equation obtained in step 3, and obtain the optimal model M $\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right.$ The expression of the objective function is $m=\min \underset{i=1}{\overset{\mathrm{no}}{\mathrm{\&Sigma;}}}f\left({\mathrm{\&omega;}}_j\right);$ Step 5, solving the minimum value of the optimization model M, and obtaining the weight factor ω _j for each loudspeaker signal adjustment, j=1,2,...n; Step 6. Adjust the signals of each speaker in the initial n-channel speaker system according to the weight factor ω _j obtained in step 5, j=1, 2,...n, to obtain a new n-channel speaker system.

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