JP2014220614A - Sound signal processing device, sound reproduction apparatus and sound signal processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound signal processing device which calculates a driving signal in accordance with a position of a listener so as to generate a sound image at a predetermined depth position.SOLUTION: A sound signal processing device 2 comprises: virtual sound image position setting means 21 for setting a virtual sound image position; listening position obtaining means 22 for obtaining information on a listening position; virtual sound source position calculating means 24 for calculating, with the use of the virtual sound image position, an arrangement position of linear speaker arrays SPAand SPAand the listening position, a virtual sound source position of each of the linear speaker arrays; and driving signal calculating means 25 for calculating, based on the wavefield synthesis (WFS) theory, a driving signal for each of the linear speaker arrays, with the use of the virtual sound source position, the speaker unit arrangement position and the listening position.

Description

  The present invention relates to a technique for driving a speaker array in which a plurality of speakers are linearly arranged.

A speaker array device in which a large number of speaker units are arranged in a plane or a straight line can reproduce the wavefront from a virtual sound source set on the front side or the back side of the speaker array, and has a three-dimensional sound direction sense. A sense of distance can be given to the listener. However, when a sound image is given to a listener by combining a plurality of linear speaker arrays, the sound image may not be localized at a desired position depending on the position of the listener.
Hereinafter, the problem will be described together with the description of the prior art.

As a technique for reproducing a physical characteristic of an original sound field using a speaker array and giving a desired sound image localization, there is signal processing by a wave field synthesis method (WFS) (see, for example, Non-Patent Document 1). WFS is a theory that reproduces the physical characteristics of an original sound field in a region surrounded by a closed curved surface. As shown in FIG. 1A, the incoming sound S _n (ω) from the primary sound source SF is observed at a plurality of positions on the boundary surface S of the original sound field. Then, as shown in FIG. 1B, the drive signal Q _n (ω) calculated therefrom is reproduced on the boundary surface S, for example, within the closed region surrounded by the boundary surface S. Reproduce the wavefront equivalent to. As a result, the listener L in the reproduced sound field inside the closed region can recognize the sound source as if there is a sound source at the position of the primary sound source SF recognized by the listener L in the original sound field. Here, the subscript n of each signal indicates the number of the corresponding observation position.
“Ω” indicates an angular frequency, and the incoming sound S _n (ω) and the drive signal Q _n (ω) are expressed as a function of the angular frequency ω. Hereinafter, the description of “ω” may be omitted.

Here, the incoming sound from the primary sound source SF is actually indicated by a plurality of microphones MC _n (“◯” in FIG. 1A) arranged on the boundary surface S. n is a microphone corresponding to the observation position described above. The position of the set primary sound source SF and a plurality of speaker units SP _n (indicated by “Δ” in FIG. 1B. N corresponds to the observation position described above). It may be obtained on a computer from the positional relationship of the speaker array which is an array of the speaker numbers.

The primary sound source set in the latter is also called a virtual sound source. Drive signal Q _n for the speaker units SP _n constituting the speaker array, the reproduction signal S of the virtual sound source SV (omega), the time delay and amplitude that depends on the path length from the position of the virtual sound source SV to the speaker unit SP _n Calculated by adding attenuation.

Generally WFS not a closed surface, it is often implemented in a speaker array in which a plurality of speaker units SP _n finite flat and straight. For example, as shown in FIG. 2, in the case of a linear speaker array SPA in which N speaker units SP _n (n = 1 to N) are arranged linearly on the x-axis at equal intervals with the arrangement interval Δx, drive signal _{Q n} for the speaker units SP _n located at a position _{r n} of the upper (omega) can be given as an expression (1).

Here, the drive signal Q _n (ω) is expressed in the frequency domain. In FIG. 2, the horizontal direction is the x-axis, the vertical direction is the y-axis, and the depth direction from the linear speaker array SPA toward the listener L is the z-axis. At this time, assuming that the position r ₀ of the virtual sound source SV is (x ₀ , 0, z ₀ ) and the position r _L of the listener _L is (x ₀ , 0, z _L ), the listener L and the linear speaker array SPA. Is the distance | z _L |, and the distance between the listener L and the virtual sound source SV is | z _L −z ₀ |.

In equation (1), j is an imaginary unit, c represents the speed of sound in the air, and φ _n is a vertical line and vector drawn from the position r ₀ to the straight line (ie, the x axis) on which the linear speaker array is arranged. An angle formed with (r _n −r ₀ ) (that is, an angle indicating the arrangement direction of the speaker unit SP _n viewed from the position r ₀ ). S (ω) is a reproduction signal of the virtual sound source SV described in the frequency space, G ₀ (φ, θ, ω) is a directivity characteristic of the virtual sound source SV, and G _n (φ, θ, ω) is a speaker. It represents the directivity of the unit SP _n.
The directivity characteristics G ₀ and G _n are expressed as a function of an azimuth angle φ that is an angle with the zy plane (vertical plane), an elevation angle θ that is an angle with the xz plane (horizontal plane), and an angular frequency ω. Further, when the elevation angle θ is a negative value, it indicates a depression angle, but unless otherwise specified, in this specification, the elevation angle θ is also included including the depression angle.

Thus, when the drive signal Q _n calculated by the expression (1) is reproduced using the linear speaker array SPA, the listener L who is on the plane formed by the position of the virtual sound source SV and the straight line arranged by the linear speaker array SPA. On the other hand, the same wavefront as that of the original sound field can be provided, and the sound image localization including the depth direction of the linear speaker array SPA can be controlled.

However, in media that simultaneously present video and sound, the display or screen that displays the video is positioned in front of the listener L, and the linear speaker array SPA is generally arranged at the outer periphery of the display or the like. Therefore, as shown in FIG. 3 (b), the listener L position setting virtual sound source SV ₀ position and the linear loudspeaker array SPA is a plane formed by the straight line arrangement (3, on the xz plane) Is not. Linear speaker array SPA, as shown in FIG. 3 (a), the listener in the horizontal direction of the L (x-axis direction) can be reproduced equivalent wavefront to that emitted from a virtual sound source SV _0. However, as shown in FIG. 3B, the linear speaker array SPA reproduces a rotationally symmetric wavefront with respect to the straight line in which the speaker units SP are arranged, so that the vertical direction (y-axis direction) is only viewed from the listening position. virtual sound source SV _L in the direction of the linear loudspeaker array SPA is recognition.

In order to eliminate this restriction, there is an example in which two linear speaker arrays SPA ₁ and SPA ₂ having different heights are arranged in parallel as shown in FIG. 4 and three-dimensional sound field reproduction is attempted ( For example, refer nonpatent literature 2). In this method, a virtual sound source SV ₁ , SV ₂ is set for each of the linear speaker arrays SPA ₁ , SPA ₂ arranged in the upper layer and the lower layer to create a reproduction sound field, and these two virtual sound sources SV ₁ , SV ₂ are set. The virtual sound image SI is generated by the used panning, and is made to be perceived by the listener as an incoming sound from the direction in which the display DSP in which the linear speaker arrays SPA ₁ and SPA ₂ cannot be arranged is arranged.

In this specification, the sound source of the original sound field for calculating the drive signals Q _n of the linear speaker arrays SPA ₁ and SPA ₂ is called “virtual sound source” (SV ₁ , SV ₂ ), and the virtual sound sources SV ₁ , SV 2 _The sound image given to the listener L by the panning of ₂ is called “virtual sound image” (SI) to be distinguished.

Even when making imaginary sound image SI in a virtual source _SV 1, SV ₂ panning, the position of the virtual sound source _SV 1, SV _2, which is recognized by the position of the listener L is changed is problematic. As shown in FIG. 5, even if the virtual sound source SV _A is set for the listener L at the position r _A and the sound field is reproduced by the driving signal Q _n , the listener L is positioned at the position r _B (position r _A The position of the recognized virtual sound sources SV _B and SV _C is different from the position of the virtual sound source SV _A when moving to a position r _C (downward with respect to the position r) (leftward with respect to the position r _B ). It is known (see Non-Patent Document 3).

A. J. Berkhout, D de Vries, and P. Pogal, Journal of Acoustical Society of America, 93 (1993), p.2764. J-H Yoo, K. Choi, J. Seo, K. Kang, H. Okubo, Inter-Noise 2012 proceedings, (2012). M. N. Montag, Thesis report University of Miami, (2011).

As shown in FIG. 6, in the case where panning is performed with virtual sound sources SV _A1 and SV _{A2 using} the conventional linear speaker arrays SPA ₁ and SPA ₂ arranged in parallel, a virtual sound image is created in a three-dimensional space. The position in the depth direction (z-axis direction) of the virtual image changes depending on the position. For example, the listener when L is listening at the position r _A listener position behind the linear loudspeaker array _SPA 1, SPA ₂ as viewed from the L r _a imaginary sound image SI to make _A virtual sound source _SV A1, _{SV A2} setting the position, listener when L is moved to the position r _B, the elevation angle and the depression angle with respect to vertical linear speaker array SPA _1, SPA ₂ is changed. Therefore, the positions of the virtual sound sources SV _A1 ′, SV _A2 ′ recognized at the position r _B are around the straight lines where the corresponding linear speaker arrays SPA ₁ , SPA ₂ are arranged from the positions of the virtual sound sources SV _A1 , SV _A2 , respectively. to change the rotated movement position, the position of the imaginary sound image SI _B caused by panning varies the position r _b from the position r _a.

  The present invention was devised in view of such a problem, and when calculating a drive signal for the speaker array device, the amplitude coefficient and the time delay amount are adjusted according to the position of the listener, thereby obtaining a predetermined value. It is an object of the present invention to provide an acoustic signal processing device that calculates a drive signal for generating a sound image at a position in the depth direction, a program thereof, and an acoustic reproduction device that includes the acoustic signal processing device and the speaker array device described above.

  In order to solve the above-described problem, the acoustic signal processing device according to claim 1 drives a speaker array device in which a plurality of linear speaker arrays in which a plurality of speaker units are arranged in a straight line are arranged in one plane. An acoustic signal processing device that calculates a drive signal based on WFS (Wavefield Synthesis) theory, comprising: a virtual sound image position setting unit; a listening position acquisition unit; a virtual sound source position calculation unit; and a drive signal calculation unit. I decided to prepare.

According to this configuration, the acoustic signal processing device sets the virtual sound image position recognized when listening to the sound reproduced by the speaker array device, by the virtual sound image position setting unit. The acoustic signal processing device acquires listening position information, which is a position for listening to the sound reproduced by the speaker array device, by the listening position acquisition means.
The acoustic signal processing device calculates a virtual sound source position for each of the linear speaker arrays by using the virtual sound image position, the arrangement position of the linear speaker array, and the listening position by a virtual sound source position calculating unit. To do. At this time, the virtual sound source position calculation means uses the depth direction, which is the normal direction of the one plane, as the z-axis, and sets the direction in which the plurality of speaker units are arranged in the linear speaker array as the x-axis. If the direction perpendicular to the x-axis is the y-axis, the position in the y-axis direction is on a vertical line extending from the listening position to a straight line on which the plurality of speaker units are arranged or on an extension line of the vertical line. Then, a position in the y-axis direction at the same position as the virtual sound image in the z-axis direction, and a position in which the positions in the x-axis and z-axis directions are the same as the virtual sound image are used as virtual sound source positions for the linear speaker array. calculate. And the acoustic signal processing device uses the virtual sound source position for the linear speaker array, the arrangement position of the linear speaker array, and the listening position for each of the linear speaker arrays by the drive signal calculation means, A drive signal is calculated based on the WFS theory.
Accordingly, the acoustic signal processing device calculates a drive signal for generating a virtual sound image at the position set by the virtual sound image position setting unit according to the listening position.

  The acoustic signal processing device according to claim 2 is the acoustic signal processing device according to claim 1, wherein the speaker array device to be driven is parallel with two linear speaker arrays spaced apart in the vertical direction. Or two of the four linear loudspeaker arrays are arranged apart in parallel in the vertical direction, and the other two linear loudspeaker arrays are separated in the left-right direction. And arranged in parallel.

According to such a configuration, the acoustic signal processing device calculates the virtual sound source position for each of the two or four linear speaker arrays constituting the speaker array device by the virtual sound source position calculating means, and virtually adds the virtual sound source position to the virtual sound source position. The drive signal for each speaker unit is calculated by the drive signal calculation means so that the sound source is recognized.
As a result, the acoustic signal processing device can calculate a drive signal for generating a virtual sound image at the position set by the virtual image position setting means by panning the virtual sound source by the linear speaker array spaced apart and arranged in parallel. .

The acoustic signal processing device according to claim 3 is the acoustic signal processing device according to claim 1 or 2, wherein the drive signal calculation means outputs a drive signal for the speaker array device for each linear speaker array. The calculation was made using equation (A).
However, each parameter in the formula (A) is a parameter for one linear speaker array whose drive signal is to be calculated, n is the number of the speaker unit constituting the linear speaker array, ω is an angular frequency, Q _n (ω) is a driving signal for the angular frequency ω of the n-th speaker unit, S (ω) is a reproduction signal for the angular frequency ω of the virtual sound source, and G ₀ (φ, θ, ω) is an azimuth angle φ, The directivity characteristics of the virtual sound source at the elevation angle θ and the angular frequency ω, G _n (φ, θ, ω) are the directivity characteristics of the nth speaker unit at the azimuth angle φ, the elevation angle θ, and the angular frequency ω, j is an imaginary unit, c the speed of sound, z ₀ is a position coordinate in the depth direction of the virtual sound source, z _L is the position coordinate in the depth direction of the listening position, r ₀ is the position vector of the virtual sound source, r _n is the position vector of the n-th speaker unit, phi _n Is the virtual sound source position The angle formed by the perpendicular line extending from the straight line array to the straight line on which the linear speaker array is arranged, and the straight line connecting the virtual sound source position and the position of the nth speaker unit, Δx indicates the speaker unit placement interval, Is − (minus) when the virtual sound image position is behind the linear speaker array as viewed from the listening position, and is + (plus) when the position is the near side.

According to such a configuration, the acoustic signal processing device calculates a drive signal in which the time delay and the amplitude attenuation according to the listening position are adjusted for each speaker unit according to the equation (A).
As a result, the acoustic signal processing apparatus can calculate a drive signal for generating a virtual sound image at the position set by the virtual sound image position setting means.

According to a fourth aspect of the present invention, there is provided an acoustic reproduction device including the acoustic signal processing device according to any one of the first to third aspects and a speaker array device.
According to such a configuration, the sound reproduction device drives the speaker array device with the drive signal calculated by the sound signal processing device.
As a result, the sound reproduction device reproduces the sound field by the drive signal corresponding to the listening position, and generates a virtual sound image at the position set by the virtual sound image position setting means.

  The acoustic signal processing apparatus according to any one of claims 1 to 3 includes a computer including hardware resources such as a CPU (Central Processing Unit) and storage means (for example, a memory and a hard disk). It can also be realized by an acoustic signal processing program for causing each unit to cooperate. This program may be distributed through a communication line, or may be distributed by writing in a recording medium such as an optical disk, a magnetic disk, or a flash memory.

According to the invention described in claim 1, claim 4 or claim 5, in order to calculate the drive signal for each linear speaker array adjusted according to the listening position, a plurality of straight lines are obtained regardless of the listening position. The position of the virtual sound image generated by panning the virtual sound source by the speaker array can be kept constant.
According to the second aspect of the present invention, since the target for calculating the drive signal is the linear speaker array arranged in parallel, the drive signal for the speaker array device that can be arranged along the side of the rectangular display is calculated. be able to.
According to the third aspect of the present invention, it is possible to calculate a drive signal that is appropriately adjusted according to the listening position and that can keep the virtual sound image position constant.

It is a figure for demonstrating the concept of WFS, (a) shows the state of an original sound field, (b) shows the mode of a reproduction sound field. It is a typical top view which shows the structure of the conventional linear speaker array. It is the model explaining the mode of the wave front reproduced by the conventional linear speaker array, (a) is a top view, (b) is a side view. It is a typical perspective view for demonstrating the panning by the conventional two linear speaker arrays in parallel. It is a typical perspective view for demonstrating the mode of a virtual sound source position change by a listener's movement in the conventional linear speaker array. It is a typical perspective view for demonstrating a mode that the position of the virtual sound image produced by the conventional two parallel linear speaker array changes with a listener's movement. It is a block diagram which shows the structure of the sound reproduction apparatus which concerns on 1st Embodiment of this invention. In the sound reproducing apparatus according to the first embodiment of the present invention, it is a schematic perspective view for explaining the positional relationship of each element when a virtual sound image is set behind the linear speaker array when viewed from the listener. . In the sound reproduction apparatus according to the first embodiment of the present invention, it is a schematic perspective view for explaining the positional relationship of each element when a virtual sound image is set in front of a linear speaker array as viewed from a listener. . It is a flowchart which shows operation | movement of the sound reproduction apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the sound reproduction apparatus which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
<First Embodiment>
[Configuration of sound reproduction device]
First, the configuration of the sound reproduction device according to the first embodiment will be described with reference to FIG.
As shown in FIG. 7, the sound reproducing device 100 according to this embodiment includes a speaker array device 1 configured by arranging a plurality of speaker units SP, and a drive signal {Q _n ( and an acoustic signal processing device 2 that calculates ω)}.

The speaker array apparatus 1, a plurality of speaker units SP are constituted by linear two straight lines speakers arranged in an array _SPA 1, SPA _2, two lines speaker array _SPA 1, SPA ₂ is vertically (y-axis (Direction) and are arranged in parallel. These linear speaker arrays SPA ₁ and SPA ₂ can be arranged, for example, along the upper side and the lower side of the rectangular display DSP.

The acoustic signal processing device 2 inputs an acoustic signal S (ω) as a reproduction signal of the virtual sound source and its directivity characteristic G ₀ (φ, θ, ω) from the outside, and the acoustic signal S (ω) at a predetermined position. Is a device that calculates a drive signal {Q _n (ω)} for driving the speaker array device 1 based on the WFS theory so that a virtual sound image is generated.

[Configuration of acoustic signal processing apparatus]
Next, a detailed configuration of the acoustic signal processing device 2 according to the first embodiment will be described with reference to FIGS.
As shown in FIG. 7, the acoustic signal processing device 2 according to the present embodiment includes a virtual sound image position setting unit 21, a listening position acquisition unit 22, a speaker array information storage unit 23, a virtual sound source position calculation unit 24, Drive signal calculating means 25.

In addition, the acoustic signal processing device 2 according to the present embodiment inputs the acoustic signal S (ω) and its directivity characteristic G ₀ (φ, θ, ω), and the acoustic signal processing device 2 according to the present embodiment is placed at a predetermined position as shown in FIG. _A drive signal {Q _n (ω) for driving the speaker array device 1 composed of _two linear speaker arrays SPA ₁ and SPA ₂ arranged in parallel so that the virtual sound image SIA of the signal S (ω) is recognized. } Is calculated.
Here, {Q _n (ω)} indicates a set of drive signals (Q ₁ (ω), Q ₂ (ω),..., Q _N (ω)) for all speaker units SP.

For simplicity of explanation, as shown in FIG. 8, the two linear speaker arrays SPA ₁ and SPA ₂ are parallel lines y = y _U and line y = y _V on the xy plane (plane z = 0). It is assumed that a plurality of speaker units SP are arranged on each of them.
If the coordinates of the listener L at the position r _L are (x _L , y _L , z _L ),
y _U > y _L > y _V
And Note that the position r _L of the listener L is representative of the position r _A and the position r _B of the listener L in FIG.

Imaginary sound image position setting unit 21 sets the position _{r a} to recognize the imaginary sound image SI _A of the sound signal S (omega) to the listener L by the speaker array apparatus 1 consisting of two straight lines speaker array _SPA 1, SPA ₂ Means.
Position r _a, for example, represented by coordinates relative to the speaker array apparatus is input through an input means such as communication means, a keyboard (not shown).
Imaginary sound image position setting means 21, the information of the position r _a imaginary sound image SI _A input, and outputs the virtual sound source position calculation section 24, an imaginary used to calculate the virtual sound source positions by the virtual sound source position calculation section 24 It is set as the sound image position.

The listening position acquisition means 22 is means for acquiring information on the position r _L of the listener L. The listening position acquisition unit 22 outputs the acquired information on the position r _L of the listener L to the virtual sound source position calculation unit 24.
The listening position acquisition means 22 may automatically recognize the position r _L of the listener L, and inputs the coordinates of the listener L via the above-described input means (not shown). There is no particular limitation.
As a method for automatic recognition, for example, a method for obtaining in real time by a head tracking device or the like can be used.

The speaker array information storage means 23 is means for storing speaker array information which is information about the _two linear speaker arrays SPA ₁ and SPA ₂ constituting the speaker array device 1. The speaker array information includes arrangement position information for specifying the arrangement position of each speaker unit SP and directivity characteristics G _n (φ, θ, ω) of each speaker unit SP. The speaker array information is referred to by the virtual sound source position calculation unit 24 and the drive signal calculation unit 25.

As the arrangement position information, for each of the linear speaker arrays SPA ₁ and SPA ₂ , the positions y _U and y _{V of} the straight lines where the speaker units SP are arranged, the arrangement interval Δx, the number N of speaker units SP, and the linear speaker array SPA ₁ , SPA ₂ can be the position of the speaker unit SP (SP ₁ or SP _N ) disposed at either end.
Further, the arrangement position information may be in other forms as long as the above-described information can be specified, and may be a set of arrangement coordinates of the individual speaker units SP, for example.

Note that the speaker array information is preliminarily stored via the input unit or the communication unit (not shown) before the drive signal Q _n is calculated by the acoustic signal processing device 2. In addition, the speaker array information is appropriately changed according to the speaker array device to be driven.

Virtual sound source position calculation section 24, the information of the position r _a imaginary sound image SI _A from the imaginary sound image position setting means 21, the information of the position r _L of the listener L from the listening position acquisition unit 22, the speaker array information storage means 23 The speaker array information is input from each of the positions, and the positions r ₀₁ and r ₀₂ of the virtual sound sources SV ₁ and SV ₂ for each of the linear speaker arrays SPA ₁ and SPA ₂ are calculated.
The virtual sound source position calculating unit 24 outputs information about the calculated positions r ₀₁ and r ₀₂ of the virtual sound sources SV ₁ and SV ₂ to the drive signal calculating unit 25.
Here, the positions r ₀₁ and r ₀₂ are values that change according to the position r _L of the listener L. In the example shown in FIG. 8, as the position _{r 01, r 02,} corresponding to the position _{r A,} the position _{^r A} ^{01, r} _{A 02} of the virtual sound source _SV A1, _{SV A2} is calculated, corresponding to the position _{r B} Thus, the positions r ^B ₀₁ and r ^B _{02 of} the virtual sound sources SV _B1 and SV _B2 are calculated.
A method of calculating the positions r ₀₁ and r ₀₂ of the virtual sound sources SV ₁ and SV ₂ will be described later.

Drive signal calculating means 25, the sound signal from the outside S (omega) and the virtual sound source _SV 1, SV ₂ directional characteristic _{G 0 (φ, θ, ω} ) , and virtual source _SV 1, SV from the virtual sound source position calculation section 24 type information about the location _{r 01, r 02} of _2, and calculates the drive signals _{{Q n} (ω)} for the speaker unit SP constituting each linear loudspeaker array _{SPA 1, SPA 2 (SP 1} ~SP n) Is.
The drive signal calculation means 25 outputs the calculated drive signal {Q _n (ω)} to the speaker units SP of the linear speaker arrays SPA ₁ and SPA ₂ via speaker unit drive means such as an amplifier (not shown). .
A method for calculating the drive signal {Q _n (ω)} will be described later.

  The acoustic signal processing apparatus 2 according to the present invention includes a computer having hardware resources such as a CPU (Central Processing Unit), storage means (for example, memory, hard disk), and various signal input / output means. It can also be realized by an acoustic signal processing program for cooperative operation. This program may be distributed through a communication line, or may be distributed by writing in a recording medium such as an optical disk, a magnetic disk, or a flash memory.

<Calculation method of virtual sound source position and drive signal>
[When the position of the virtual image is set behind the straight speaker array]
(Calculation method of virtual sound source position)
Next, a method for calculating the virtual sound source position by the virtual sound source position calculating means 24 will be described with reference to FIG.
First, the listener L is, the case where the listening at the position r _A is a reference position for listening. As shown in FIG. 8, the virtual sound source position calculation section 24, the position of the listener L so recognizes the imaginary sound image SI _A to position _{r a} when listening at position _{r A} virtual sound source _SV A1, _{SV A2} Is calculated.
Here, FIG. 8, as viewed from the listener L, illustrates a case where the back side of the imaginary sound image SI linear speaker array _SPA 1 position _{r a} of _A, SPA ₂ (z-axis coordinate minus side) is set to Yes.

The elevation angle of the linear speaker array SPA ₁ viewed from the position r _A is defined as θ _A1 . Here, the elevation angle θ _A1 is a perpendicular line from the position r _A to the straight line y = y _U in the xy plane in which the speaker units SP constituting the linear speaker array SPA ₁ are arranged, and the xy plane from the position r _A This is the angle formed by the perpendicular line.
Also, the depression angle of the linear loudspeaker array SPA ₂ as viewed from the position _{r A} and theta _A2. Here, the depression angle θ _A2 is a perpendicular line from the position r _A to the straight line y = y _V in the xy plane in which the speaker units SP constituting the linear speaker array SPA ₂ are arranged, and the xy plane from the position r _A This is the angle formed by the perpendicular line.
The position _{r a} coordinate of the imaginary sound image SI _A that are set by the imaginary sound image position setting means _{21 (x a, y a,} z a) and the coordinates of the position _{r A} (0,0, _{z A)} and To do.

In this case, so that the position _{r a} imaginary sound image SI _A relative position _{r A} occurs, for each of the upper and lower linear speaker array _SPA 1, SPA _2, by the equation (2) and (3), a virtual sound source position r ^A ₀₁ and r ^A ₀₂ are calculated.
Thus, the panning of the virtual sound source _SV A1, _{SV A2} by upper and lower linear speaker array _SPA 1, SPA _2, the desired depth distance from the linear loudspeaker array _SPA 1, SPA ₂ | produce the imaginary sound image SI _A | _{z a} Can be made.

Then, the imaginary sound image SI _A reproducible sound field to produce a position r _a when listening at position r _A, the listener L is, the case where moving the listening position at the position r _B. As shown in FIG. 8, when listening at position r _B, perpendicular to the speaker units SP constituting the linear loudspeaker array SPA ₁ of the upper layer is drawn from the position r _B with respect to the straight line y = y _U in the xy plane to be arranged a on the extension of the position ^r _{a 01} to the equidistant position of the linear loudspeaker array SPA ₁ from the virtual sound source _{SV A1} is a position of the virtual sound source _{SV A1} '. Similarly, the lower linear speaker array SPA ₂ is an extension of a perpendicular line drawn from the position r _B to the straight line y = y _V in the xy plane where the speaker units SP constituting the linear speaker array SPA ₂ are arranged. Te, the position of equal distance and to the position ^r _{a 02} of the virtual sound source _{SV A2} from the linear loudspeaker array SPA ₂ is a position of the virtual sound source _{SV A2} '. By panning, so that the imaginary sound image SI _B occurs at a position away from the listener L in the depth direction from the position r _a.

Therefore, in this embodiment, the listener when L is moved to the position r _B is located with respect to the straight line y = y _U in the xy plane which the speaker units SP are arranged to constitute a linear loudspeaker array SPA ₁ r _B even on a perpendicular extension line of drawn from the depth direction of the coordinates (z-axis coordinate), and calculates the position coordinates z _a a set imaginary sound image SI _a as a position r ^B ₀₁ of the virtual sound source SV _B1.
Similarly, the lower linear speaker array SPA ₂ is an extension of a perpendicular line drawn from the position r _{B with} respect to the straight line y = y _V in the xy plane in which the speaker units SP constituting the linear speaker array SPA ₂ are arranged. a is, the depth direction of the coordinates (z-axis coordinate), and calculates the position coordinates _{z a} a set imaginary sound image SI _a as a position ^r _{B 02} of the virtual sound source _{SV B2.}

When the elevation angle of the upper linear speaker array SPA ₁ viewed from the position r _B is θ _B1 and the depression angle of the lower linear speaker array SPA ₂ viewed from the position r _B is θ _B2 , the positions of the virtual sound sources SV _B1 and SV _B2 r ^B ₀₁ and r ^B ₀₂ can be calculated by the equations (4) and (5).
That is, it can be calculated by the same procedure as that of Expression (2) and Expression (3), respectively.
Then, the virtual sound source _{SV B1} position ^r _{B 01,} by panning with the virtual sound source _{SV B2} position ^r _{B 02,} can be generated imaginary sound image at a position _{r a} imaginary sound image SI _A set.

Note that the positions r ^A ₀₁ , r ^A _{02 and the} like calculated by the equations (2) to (5) are, in other words, the depth direction that is the normal direction of the plane on which the linear speaker arrays SPA ₁ and SPA ₂ are arranged. was the z axis, the direction in which the plurality of speaker units are arranged to constitute a linear loudspeaker array _SPA 1, SPA ₂ as x-axis, perpendicular to the x-axis in the plane linear speaker array _SPA 1, SPA ₂ are arranged The y-axis direction is a vertical line extending from the listening position r _A to a straight line in which a plurality of speaker units of the linear speaker arrays SPA ₁ and SPA ₂ are arranged or an extension of the perpendicular line a line, the position of the y-axis direction in the same position as the imaginary sound image SI _a for the z-axis direction, position location in the x-axis direction and the z-axis direction is the same as the imaginary sound image SI _a Is that of.

Further, these formulas can be listening position r _A, r _B and imaginary sound image position r _a to apply even when it is set in addition to the z-axis.
Furthermore, the arrangement direction of the linear speaker array is not limited to the horizontal direction, and even if the linear speaker array is arranged in the vertical direction or the oblique direction, the speakers constituting the linear speaker array to be driven as described above. By setting the unit arrangement direction to the x-axis, the virtual sound source position with respect to the linear speaker array can be calculated by the same procedure.

(Driving signal calculation method)
Next, a driving signal calculation method by the driving signal calculation means 25 will be described.
The drive signal calculation means 25 is a virtual source of each linear speaker array SPA ₁ , SPA ₂ calculated by the virtual sound source position calculation means 24 according to the position r _L (position r _A , r _B etc.) of the listener L. Using the sound source positions r ^A ₀₁ , r ^A _{02 and the} like, the drive signal Q _n is calculated for each speaker unit SP constituting each linear speaker array.

For example, when the drive signal Q _n for the speaker unit SP _n (n = 1 to N) of the upper linear speaker array SPA ₁ is calculated at the position r _A , the virtual sound source SV _A1 of the linear speaker array SPA ₁ is calculated. The drive signal Q _n is calculated by substituting the position r ^A ₀₁ and its z coordinate z ^A ₀₁ into r ₀ and z ₀ of the above-described equation (1). That is, the drive signal Q _n is calculated using Equation (6).
For each loudspeaker unit SP _n , an angle φ _n (which is formed by a perpendicular line drawn from a known arrangement position r _n , position r ^A ₀₁ to a straight line (y = y _U ) in the xy plane and a vector (r _n −r ₀ )) That is, the drive signal Q _n can be calculated by substituting the angle indicating the arrangement direction of the speaker unit SP _n viewed from the position r ^A ₀₁ and the directivity characteristic G _n (φ, θ, ω). .

For the lower linear speaker array SPA ₂ , the position r ^A ₀₂ and its z coordinate z ^A ₀₂ of the virtual sound source SV _A2 are used in the same manner instead of the position r ^A ₀₁ and its z coordinate z ₀ in equation (6). it is possible to calculate the drive signal Q _n. Similarly, if the listener L is position _{r B,} in the formula (1), together with the use of _{z B} as the distance _{z L,} the position of the virtual sound source _SV B1, _{SV B2} as the position _{r 0} and z coordinates _{z 0} Using r ^B ₀₁ , r ^B ₀₂ and their z coordinates z ^B ₀₁ , z ^B ₀₂ , the driving signal Q _n of the speaker unit SP _n constituting each of the upper and lower linear speaker arrays SPA ₁ , SPA ₂ is calculated. can do.
The calculation of the drive signal Q _n may be performed by substituting the position r _{0 of the} virtual sound source into an expression in which a part of the expression (1) is omitted by approximation in addition to using the expression (1). Is possible.

Even when the listener L moves the listening position by driving the speaker units SP _n constituting the linear speaker arrays SPA ₁ and SPA ₂ using the drive signal Q _n calculated by the above procedure, the listener The position of the virtual image recognized by L can be kept constant.

FIG. 8 shows the case of z _A <z _B (that is, movement from the reference position r _{A in} the positive direction of the z axis), but conversely, z _A > z _B (similarly, in the negative direction of the z axis). Even in the case of movement), the drive signal Q _n can be calculated in the same procedure. Further, the movement of the listening position is not limited to the depth direction, and the movement in the horizontal direction (x-axis direction) and the vertical direction (y-axis direction), that is, the coordinate x _B different from the coordinate x _A, and the coordinate y _A The drive signal Q _n can be calculated according to the above-described procedure even when the coordinate y _B is changed.
The same applies to the example shown in FIG.

[When the position of the virtual image is set in front of the linear speaker array]
Next, referring to FIG. 9 (see appropriately FIGS. 7 and 8), when the position _{r a} imaginary sound image SI _A set in front of the linear loudspeaker array _SPA 1, SPA _2, the virtual sound source _{SV A1} ^A method for calculating the position r ^A _{01 and the} like and the drive signal Q _n will be described.
The example shown in Figure 9, for the example shown in FIG. 8, an imaginary sound image SI the setting position _{r a} of _A, listener linear speaker array _SPA 1 as viewed from the L, SPA ₂ front of the ( The z-axis coordinate is the plus side). Positions, angles and the like corresponding to the example shown in FIG.

(Calculation method of virtual sound source position)
Position _{r a} imaginary sound image SI _A is, if it is set on the front side than the linear loudspeaker array _SPA 1, SPA _2, the position _{^r A} ^{01, r} _{A 02} of the virtual sound source _SV A1, _{SV A2,} the formula (7 ) And equation (8).
The positions r ^A ₀₁ and r ^A ₀₂ calculated by the equations (7) and (8) are straight lines y = y in the xy plane where the respective speaker units SP constituting the linear speaker arrays SPA ₁ and SPA ₂ are arranged. even on a perpendicular line drawn from the position r _a against _U and the straight line y = y _V, the depth direction of the coordinates (z-axis coordinate), that the position with coordinates z _a a set imaginary sound image SI _a is there.

Then, the sound field imaginary sound image is reproduced as occurs in the position r _a when listening at position r _A, the listener L is, the case where moving the listening position at the position r _B. As shown in FIG. 9, when listening at position r _B, even on a perpendicular upper linear speaker array SPA ₁ is drawn from the position r _B with respect to the straight line y = y _U in the xy plane to be arranged, linear position equidistant and from the speaker array SPA ₁ to the position ^r _{a 01} virtual sources _{SV A1} is a position of the virtual sound source _{SV A1} '. Similarly, the lower the linear loudspeaker array SPA _2, even on a perpendicular straight line speaker array SPA ₂ is drawn from the position _{r B} with respect to the straight line y = _{y V} in the xy plane to be arranged, from the linear loudspeaker array SPA ₂ position of equal distance and to the position ^r _{a 02} of the virtual sound source _{SV A2} is the position of the virtual sound source _{SV A2} '. By panning, so that the imaginary sound image SI _B occurs at a position close to the listener L in the depth direction from the position r _a.

Therefore, the position _{r a} imaginary sound image SI _A, when the straight line speaker array _SPA 1, SPA ₂ were set to the front side, when the listener L has moved to the position _{r B} is straight speaker array SPA ₁ is a on perpendicular dropped from position r _B with respect to the straight line y = y _U in the xy plane to be arranged, the depth direction of the coordinates (z-axis coordinate), coordinates z _a a set imaginary sound image SI _{a Is} calculated as the position r ^B ₀₁ of the virtual sound source SV _B1 .
Similarly, the lower-level linear speaker array SPA ₂ is also a vertical line drawn from the position r _{B with} respect to a straight line y = y _V in the xy plane in which the linear speaker array SPA ₂ is arranged, and is a coordinate in the depth direction. the (z-axis coordinate), and calculates the position coordinates _{z a} a set imaginary sound image SI _a as a position ^r _{B 02} of the virtual sound source _{SV B2.}

That is, the positions r ^B ₀₁ and r ^B ₀₂ can be calculated by the equations (9) and (10).
That is, it can be calculated by the same procedure as that in the equations (7) and (8).
Then, the virtual sound source _{SV B1} position ^r _{B 01,} by panning with the virtual sound source _{SV B2} position ^r _{B 02,} can be generated imaginary sound image at a position _{r a} imaginary sound image SI _A set.

Note that the positions r ^A ₀₁ , r ^A _{02 and the} like calculated by the equations (7) to (10) are the same as those in the equations (2) to (5) described above, because the linear speaker arrays SPA ₁ and SPA ₂ are The depth direction, which is the normal direction of the plane to be arranged, is defined as the z-axis, the direction in which the plurality of speaker units constituting the linear speaker arrays SPA ₁ and SPA ₂ are arranged as the x-axis, and the linear speaker arrays SPA ₁ and SPA ₂ When the direction perpendicular to the x-axis is the y-axis in the plane where the speaker is arranged, the y-axis direction position is arranged from a listening position r _A to a plurality of speaker units of linear speaker arrays SPA ₁ and SPA _2. and a extension of the perpendicular on or the perpendicular line drawn to the straight line, the position of the y-axis direction in the same position as the imaginary sound image SI _a for z-axis direction, the position of the x-axis direction and the z-axis direction Kyoon It is that the position is the same as the image SI _A.
Further, it is also these equations, applied even when the listening position r _A, r _B and imaginary sound image position r _a is set to non on the z-axis.

(Driving signal calculation method)
Next, a driving signal calculation method by the driving signal calculation means 25 will be described.
The drive signal calculation means 25 is a virtual source of each linear speaker array SPA ₁ , SPA ₂ calculated by the virtual sound source position calculation means 24 according to the position r _L (position r _A , r _B etc.) of the listener L. Using the sound source positions r ^A ₀₁ , r ^A _{02 and the} like, the drive signal Q _n is calculated for each speaker unit SP _n constituting each linear speaker array.

Position r _a imaginary sound image SI _A is, if the straight line speaker array SPA _1, SPA ₂ were set to the front side, taking into account the direction of travel of the wave front, the exponent indicating a time delay in the formula (1) The drive signal Q _n can be calculated using Expression (11) in which the sign is changed to “+”.
The position listener L is the case of the position _{r A,} with substituting _{z A} as _{z L,} which is calculated using equation (7) or (8) as the position _{r 0} and z coordinates _{z 0} r ^A ₀₁ and r ^A ₀₂ and their z coordinates z ^A ₀₁ and z ^A ₀₂ are substituted. When the listener L is at the position r _B , z _B is substituted as z _L , and the position r ₀ and its z coordinate z ₀ are calculated using the formula (9) or the formula (10). r ^B ₀₁ and r ^B ₀₂ and their z coordinates z ^B ₀₁ and z ^B ₀₂ are substituted.
By the above procedure, it is possible to calculate the drive signal Q _n.

In addition, if Formula (1) and Formula (11) are put together into one, it can represent like Formula (A).
However, ± of the exponent part is − (minus) when the virtual image position is behind the linear speaker array when viewed from the listening position, and + (plus) when the position is nearer.

[Operation of sound reproduction device]
Next, the operation of the sound reproduction device 100 according to the present embodiment will be described with reference to FIG. 10 (refer to FIGS. 7 to 9 as appropriate).
Sound reproducing apparatus 100 according to this embodiment, as shown in FIG. 10, first, the imaginary sound image position setting means 21 of the audio signal processor 2, sets the position r _a imaginary sound image SI _A causing the reproduction sound field (Step S1).
Note that the speaker array information, which is information such as the position r _n where the speaker units SP _n constituting the linear speaker arrays SPA ₁ and SPA ₂ of the speaker array device 1 are arranged, and the directivity characteristic G _n , is stored in advance as an acoustic signal processing device. 2 is stored in the speaker array information storage means 23.

Next, the sound reproducing device 100 acquires information on the listening position r _L by the listener L by the listening position acquisition unit 22 of the sound signal processing device 2 (step S2).
Note that the listening position acquisition unit 22 may acquire the position r _L of the listener L at all times or at an appropriate time interval during sound reproduction and output the position r _L to the virtual sound source position calculation unit 24.

Next, a sound reproducing apparatus 100, by the virtual sound source position calculation section 24 of the audio signal processor 2, the position r _a imaginary sound image SI that is set by the imaginary sound image position setting means _21, which is acquired by listening position obtaining unit 22 Using the position r _L (r _A , r _B, etc.) of the listener L and the speaker array information stored in the speaker array information storage means 23 in advance, Expression (2) to Expression (5) or Expression (7) To the position r ₀₁ (r ^A ₀₁ ) of the virtual sound sources SV ₁ (SV _A1 , SV _B1 etc.), SV ₂ (SV _A1 , SV _B1 etc.) by the upper and lower linear speaker arrays SPA ₁ , SPA ₂ , R ^B _01, etc.) and position r ₀₂ (r ^A ₀₂ , r ^B _02, etc.) are calculated (step S3).

Next, the sound reproducing device 100 is driven by the drive signal calculating unit 25 of the sound signal processing device 2.
The position r _L of the listener L acquired by the listening position acquisition unit 22, the speaker array information stored in advance in the speaker array information storage unit 23, the acoustic signal S (ω) input from the outside, and the directivity characteristic G ₀ Using (φ, θ, ω), the drive signal {Q _n } for each speaker unit SP _n constituting the upper and lower linear speaker arrays SPA ₁ and SPA ₂ is calculated by the equation (A) (step S4). .
Note that the sound reproduction device 100 uses the drive signal calculation unit 25 to calculate the drive signal {Q _n } in real time in accordance with the input of the sound signal S (ω) and the directivity characteristics G ₀ (φ, θ, ω). Alternatively, the acoustic signal S (ω) and the directivity characteristic G ₀ (φ, θ, ω) are stored in a storage unit (not shown), and then the drive signal {Q _n } is calculated collectively. Also good.

The sound reproducing device 100 reproduces sound by outputting the drive signal {Q _n } calculated in step S4 to the corresponding speaker unit SP _n via a driving unit (not shown) (step S5).
Note that if the position r _L of the listener L acquired by the listening position acquisition unit 22 is changed during sound reproduction, the sound reproducing device 100 causes the virtual sound source position calculation unit 24 to change the listening position r after the change. calculates a virtual sound source position _{r 01, r 02} based _L, and the drive signal by calculating means 25, a virtual sound source position _{r 01,} the drive signal using the _{r 02,} calculated based on the listening position _{r L} of the changed Assume that {Q _n } is calculated.

Second Embodiment
Next, with reference to FIG. 11, a sound reproduction device 100A according to a second embodiment of the present invention will be described.
As shown in FIG. 11, the sound reproducing device 100A according to the second embodiment includes a speaker array device 1A instead of the speaker array device 1 in the sound reproducing device 100 according to the first embodiment shown in FIG. It is.

In the speaker array device 1A according to the second embodiment, two linear speaker arrays SPA ₁ and SPA _{2 in} which a plurality of speaker units SP are arranged on a straight line extending in the horizontal direction are spaced apart in the vertical direction and arranged in parallel. The two linear speaker arrays SPA ₃ and SPA _{4 in} which a plurality of speaker units SP are arranged on a straight line extending in the vertical direction are arranged in parallel apart from each other in the vertical direction. Further, these four linear speaker arrays SPA ₁ , SPA ₂ , SPA ₃ , SPA ₄ are arranged in the same plane. These four linear speaker arrays SPA ₁ , SPA ₂ , SPA ₃ , SPA ₄ are arranged along, for example, the upper side, the lower side, the right side, and the left side, which are the four sides of the rectangular display DSP, and are configured in a window frame type You can also

Similar to the sound reproducing device 100 in the first embodiment, the sound reproducing device 100A in the second embodiment has four linear speaker arrays SPA ₁ according to the position r _L of the listener L by the drive signal calculating means 25. , _{SPA 2,} SPA 3, by panning a virtual sound source which is formed by SPA _4, as imaginary sound image is recognized at the position _{r a} set, these linear speaker array _{SPA 1, SPA 2, SPA 3} , SPA 4 The drive signal Q _n for each speaker unit SP _n that constitutes is calculated.

In the second embodiment, for the linear speaker arrays SPA ₁ and SPA _{2 in} which a plurality of speaker units SP are arranged on a straight line extending in the horizontal direction, the calculation of the virtual sound source position and the drive signal are calculated in the same procedure as in the first embodiment. Calculations can be made. For the linear speaker arrays SPA ₃ and SPA _{4 in} which the speaker units SP are arranged on a vertical straight line, the virtual sound source position is calculated and driven in the same procedure as in the first embodiment by switching the x coordinate and the y coordinate. Signals can be calculated. Therefore, a detailed description of the virtual sound source position and the drive signal calculation method is omitted.
Moreover, since the sound reproducing device 100A according to the second embodiment is the same as the sound reproducing device 100 according to the first embodiment except that the number of linear speaker arrays to be driven is four, the second embodiment. Detailed description of the acoustic signal processing device 2 in FIG.

In the embodiment described above, an example in which two or four linear speaker arrays are combined as the speaker array device to be driven has been described. However, the present invention is not limited to this, and an arbitrary number of linear speakers is used. The method of the present invention can also be applied to a system configured by combining arrays.
Further, in the case where four linear speaker arrays are arranged along the four sides of the rectangle, the length of the linear speaker array and the length of the four sides of the rectangle are not limited to be substantially the same. be able to.
Furthermore, for example, the present invention can be applied to a case where a 22.2 channel acoustic signal for Super Hi-Vision is reproduced by a speaker array device configured in a window frame type, which facilitates reproduction of three-dimensional sound in a home environment. it can.

  As described above, the acoustic signal processing device and the sound reproducing device according to the embodiments of the present invention have been specifically described by the embodiments for carrying out the invention, but the gist of the present invention is not limited to these descriptions. It should be construed broadly based on the claims. Needless to say, various changes and modifications based on these descriptions are also included in the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1,1A Speaker array apparatus 2 Acoustic signal processing apparatus 21 Virtual sound image position setting means 22 Listening position acquisition means 23 Speaker array information storage means 24 Virtual sound source position calculation means 25 Drive signal calculation means 100, 100A Sound reproduction apparatus SPA ₁ , SPA ₂ , SPA ₃ , SPA ₄ linear speaker array SP, SP _n speaker unit

Claims (5)

A linear speaker array in which a plurality of speaker units are arranged linearly is an acoustic signal processing device that calculates a drive signal for driving a plurality of speaker array devices arranged in one plane based on WFS (Wavefield Synthesis) theory. And
A virtual sound image position setting means for setting a virtual sound image position recognized when listening to the sound reproduced by the speaker array device;
Listening position acquisition means for acquiring information of a listening position that is a position for listening to sound reproduced by the speaker array device;
Virtual sound source position calculating means for calculating a virtual sound source position for each linear speaker array using the virtual image position, the arrangement position of the linear speaker array, and the listening position;
Drive signal calculation means for calculating a drive signal based on WFS theory using the virtual sound source position for the linear speaker array, the arrangement position of the linear speaker array, and the listening position for each linear speaker array And comprising
The virtual sound source position calculating means includes
The depth direction that is the normal direction of the one plane is the z axis, the direction in which the plurality of speaker units are arranged in the linear speaker array is the x axis, and the direction orthogonal to the x axis in the one plane is the y axis. If
The position in the y-axis direction is on a perpendicular line extending from the listening position to a straight line in which the plurality of speaker units are arranged or on an extension line of the perpendicular line, and the y-axis direction at the same position as the virtual image in the z-axis direction And a position where the position in the x-axis and z-axis directions is the same as the virtual sound image is calculated as a virtual sound source position for the linear speaker array.   The speaker array device to be driven is one in which two linear speaker arrays are arranged in parallel in the vertical direction, or two linear speaker arrays in the four linear speaker arrays are in the vertical direction. 2. The acoustic signal processing apparatus according to claim 1, wherein the acoustic signal processing apparatus is arranged in parallel with a distance from each other, and the other two linear speaker arrays are spaced apart in the left-right direction and arranged in parallel. 3. The acoustic signal processing according to claim 1, wherein the drive signal calculation unit calculates a drive signal for the speaker array device using the formula (A) for each of the linear speaker arrays. 4. apparatus.
However, each parameter in the formula (A) is a parameter for one linear speaker array whose drive signal is to be calculated,
n is the number of the speaker unit constituting the linear speaker array,
ω is angular frequency,
Q _n (ω) is a drive signal for the angular frequency ω of the n-th speaker unit,
S (ω) is the reproduction signal for the angular frequency ω of the virtual sound source,
G ₀ (φ, θ, ω) is the directivity characteristic of the virtual sound source at the azimuth angle φ, the elevation angle θ, and the angular frequency ω,
G _n (φ, θ, ω) is the directivity characteristic of the n-th speaker unit at the azimuth angle φ, the elevation angle θ, and the angular frequency ω,
j is an imaginary unit,
c is the speed of sound,
z ₀ is the position coordinate in the depth direction of the virtual sound source,
z _L is the position coordinate in the depth direction of the listening position,
r ₀ is the position vector of the virtual sound source,
r _n is the position vector of the n-th speaker unit,
φ _n is an angle formed by a perpendicular line extending from the virtual sound source position to the straight line where the linear speaker array is arranged, and a straight line connecting the virtual sound source position and the position of the nth speaker unit,
Δx is the speaker unit interval,
Respectively,
The exponent of ± is − (minus) when the virtual sound image position is behind the linear speaker array as viewed from the listening position, and + (plus) when it is in front. The acoustic signal processing device according to any one of claims 1 to 3,
A speaker array device driven by a drive signal calculated by the acoustic signal processing device;
A sound reproducing apparatus comprising:   An acoustic signal processing program for causing a computer to function as the acoustic signal processing device according to any one of claims 1 to 3.