Reproduction control device, reproduction control method, and program for area reproduction

Abstract

One aspect of the present invention is a playback control device for performing, using a circular speaker array in which a plurality of speakers are arranged facing inward in circular form, area playback of sound inside the circular speaker array. This playback control device comprises a desired sound field definition processing unit that defines a desired sound field from inputted desired sound field data, an optimization problem definition processing unit that defines an optimization problem for obtaining the defined desired sound field, a sound field control filter design processing unit that designs a sound field control filter using a proximal splitting algorithm on the basis of the defined optimization problem, and a drive signal generation processing unit that applies the filter to an inputted acoustic signal to thereby generate a drive signal that is inputted to each speaker in the circular speaker array.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a playback control device, a playback control method, and a program for area playback. [Background technology]

[0002] In recent years, area reproduction, which presents sound only in a specific area, has become widespread in public spaces such as train stations, art galleries, and museums. In particular, area reproduction using methods that control conventional speakers, such as ultrasonic speakers with super-directionality using ultrasonic waves and bar speakers with multiple built-in speakers, is being studied. However, ultrasonic speakers are generally known to degrade sound quality when demodulating ultrasonic waves into audible sound.

[0003] Meanwhile, in games and movies, efforts are being made to achieve a sense of realism by reproducing the sound's arrival direction, wavefront, and volume in accordance with the video. However, it is difficult for ultrasonic speakers to accurately reproduce the sound's arrival direction, wavefront, and volume. Furthermore, while bar speakers can reproduce a wavefront from a specific direction, it is difficult to reproduce sounds coming from directions where the speakers are not located.

[0004] Patent Document 1 proposes a method for realizing area reproduction using a speaker array to present sound only in a specific area and prevent sound from leaking to other areas. Other methods for realizing area reproduction using a speaker array include methods that use the least squares method and acoustic contrast maximization technology.

[0005] The technique for realizing area reproduction using a speaker array involves placing multiple control points on a speaker array with multiple speakers, designing a filter that controls the amplitude and phase of each speaker based on the transmission characteristics from each speaker to each control point, and applying that filter to the input signal of each speaker to control the sound field observed at the control points so that it matches the desired sound field.

[0006] Acoustic contrast maximization technology is a technology that uses a speaker array to maximize the sound pressure ratio between a bright zone, which is an area where a sound is presented arbitrarily set for the speaker array, and a dark zone, which is an area where sound is suppressed.

[0007] It is possible to design a filter using a technique based on acoustic contrast maximization to generate a desired sound field, i.e., a bright zone where sound is presented and a dark zone where sound is suppressed. However, acoustic contrast maximization cannot reproduce the desired wavefront. Furthermore, the calculated filter may have a large low-frequency filter gain that exceeds the speaker's allowable vibration, resulting in distorted sound and difficulty in reproduction. In response to this problem, Non-Patent Document 1 proposes a method for suppressing filter gain by using a penalty term to suppress the filter gain.

[0008] On the other hand, sound leakage into the dark zone, which is a silent area, occurs to a considerable extent. Non-Patent Document 2 proposes a method for suppressing sound leakage by controlling the weight ratio between minimizing the error with the desired sound field in the bright zone and minimizing the acoustic energy in the dark zone using parameters. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2013-110495 [Non-patent literature]

[0010] [Non-Patent Document 1] MM. Boone, WH. Cho, and JG Ih. "Design of a highly directional endfire loudspeaker array." Journal of the Audio Engineering Society 57.5 (2009): 309-325. [Non-patent document 2] Betlehem, Terence, et al. "Personal sound zones: Delivering interface-free audio to multiple listeners." IEEE Signal Processing Magazine 32.2 (2015): 81-91. Summary of the Invention [Problem to be solved by the invention]

[0011] In the method of Non-Patent Document 1, which suppresses the filter gain using a penalty term, the filter gain can be suppressed, but sound leakage into the dark zone occurs to a considerable extent.

[0012] In the method of Non-Patent Document 2, if emphasis is placed on the reproduction of the sound field, sound leakage into the dark zone occurs, and if emphasis is placed on minimizing acoustic energy, the reproducibility of the sound field in the bright zone decreases.

[0013] This invention was made in light of the above circumstances, and its purpose is to provide a technology that suppresses the gain applied to each speaker in a speaker array, while reproducing a desired wavefront in the bright zone and realizing area reproduction that suppresses sound leakage into the dark zone. [Means for solving the problem]

[0014] One aspect of the present invention is a playback control device for using a circular speaker array in which multiple speakers are arranged inward in a circle to play back sound within the circular speaker array. The playback control device includes a desired sound field definition processing unit that defines a desired sound field from input desired sound field data, an optimization problem definition processing unit that defines an optimization problem for obtaining the defined desired sound field, a sound field control filter design processing unit that designs a sound field control filter using a proximity separation algorithm based on the defined optimization problem, and a drive signal generation processing unit that generates a drive signal to be input to each speaker of the circular speaker array by applying the filter to an input acoustic signal. The optimization problem definition processing unit calculates, as the optimization problem, a sum of squares of filter coefficients l for suppressing speaker gain for an optimization problem for reproducing the desired sound field. 2 By introducing a norm and assuming that the reproduced sound field is sparse, we can obtain the mixture of the reproduced sound field l 1,2 Define an optimization problem that introduces a norm.

[0015] One aspect of the present invention is a playback control method for reproducing sound within a circular speaker array using a circular speaker array in which multiple speakers are arranged inward in a circular shape. The playback control method includes the steps of: defining a desired sound field from desired sound field data; defining an optimization problem for obtaining the desired sound field; designing a filter for sound field control using a proximity separation algorithm based on the optimization problem; and generating a drive signal to be input to each speaker of the circular speaker array by applying the filter to an input acoustic signal. The step of defining the optimization problem includes: defining a sum of squares of filter coefficients l for suppressing speaker gain for an optimization problem for reproducing the desired sound field; 2 By introducing a norm and assuming that the reproduced sound field is sparse, we can obtain the mixture of the reproduced sound field l 1,2 Define an optimization problem that introduces a norm.

[0016] One aspect of the present invention is a program for using a circular speaker array in which multiple speakers are arranged inward in a circular shape to reproduce sound within an area inside the circular speaker array, the program causing a processor included in the playback control device to execute the processes performed by each of the processing units included in the playback control device. [Effects of the Invention]

[0017] According to one aspect of the present invention, it is possible to provide a technology that realizes area reproduction by suppressing the gain applied to each speaker in a speaker array, reproducing a desired wavefront in a bright zone, and suppressing sound leakage into a dark zone. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of an area playback system including a playback control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing an example of a hardware configuration of the playback control device shown in FIG. [Figure 3] FIG. 3 is a block diagram showing an example of a software configuration of the playback control device shown in FIG. [Figure 4] FIG. 4 is a flowchart showing an example of a processing procedure and processing contents performed by the playback control device shown in FIG. [Figure 5] FIG. 5 is a diagram showing an observation system for explaining an example of a filter design technique for sound field reproduction using the least squares method. [Figure 6] FIG. 6 is a diagram showing an observation system for explaining an example of the acoustic contrast maximization technique. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] [One embodiment] (Configuration example) (1) System FIG. 1 is a diagram showing the overall configuration of an area playback system including a playback control device according to an embodiment of the present invention.

[0021] The area reproduction system according to one embodiment includes a circular speaker array SP, a reproduction control device 1 that supplies an acoustic drive signal BS to the circular speaker array SP, and an input / output device 2 connected to the reproduction control device 1.

[0022] The circular speaker array SP is made up of multiple speakers SP1 to SP2 arranged in a circle. L For example, the speakers SP1 to SP L are arranged at equal intervals on the same circumference. L are arranged so that their sound emission direction faces the center of the circumference.

[0023] The circular speaker array SP is driven by an acoustic drive signal BS supplied from the playback control device 1, and emits sound toward the inside of the circular speaker array SP, thereby forming a bright zone BZ and a dark zone DZ inside the circular speaker array SP.

[0024] The input / output device 2 is, for example, a personal computer or a mobile terminal such as a smartphone used by a system administrator or a user, and is used to input information about a desired sound field to the playback control device 1. The input / output device 2 may be, for example, a television remote control or an operation panel of a car navigation device, and the connection means between the input / output device 2 and the playback control device 1 may be a wireless interface such as Bluetooth (registered trademark), WiFi (registered trademark), or a mobile communication network, in addition to a wired cable.

[0025] (2) Playback control device 1 2 and 3 are block diagrams showing the hardware and software configurations of the playback control device 1, respectively.

[0026] The playback control device 1 includes a control unit 10 that uses a hardware processor such as a central processing unit (CPU). A storage unit having a program storage unit 20 and a data storage unit 30, an input / output interface (hereinafter, an interface will be referred to as an I / F) 40 to which an input / output device 2 is connected, and an audio signal I / F 50 are connected via a bus 60 to the control unit 10.

[0027] The acoustic signal I / F 50 receives an acoustic signal output from a sound source (not shown) and outputs an acoustic drive signal BS generated by a control unit 10 (to be described later) to each of the speakers SP1 to SP2 of the circular speaker array SP. L Used to output to

[0028] The program storage unit 20 is configured, for example, by combining a non-volatile memory such as an HDD (Hard Disk Drive) or SSD (Solid State Drive) as a storage medium that can be written to and read at any time, with a non-volatile memory such as a ROM (Read Only Memory), and stores programs necessary for executing various control processes according to one embodiment, in addition to middleware such as an OS (Operating System).

[0029] The data storage unit 30 is, for example, a combination of a non-volatile memory such as an HDD or SSD, which can be written to and read from at any time, and a volatile memory such as a RAM (Random Access Memory), as a storage medium, and is equipped with a desired sound field storage unit 31 and a filter storage unit 32 as the main storage units required to implement one embodiment.

[0030] The desired sound field storage unit 31 is used to store a desired sound field defined by the control unit 10. The filter storage unit 32 is used to store a filter for sound field control calculated by the control unit 10.

[0031] The control unit 10 includes, as processing functions necessary for implementing one embodiment, a desired sound field definition processing unit 11, an optimization problem definition processing unit 12, a sound field control filter design processing unit 13, and a drive signal generation processing unit 14. These processing units 11 to 14 are all realized by causing a hardware processor of the control unit 10 to execute a program stored in a program storage unit 20.

[0032] The desired sound field definition processing unit 11 receives the desired sound field data DS output from the input / output device 2 via the input / output I / F 40, defines a desired sound field consisting of a Bright zone, which is an area that reproduces any desired wavefront, and a Dark zone, which is an area that suppresses sound, and performs processing to store the defined desired sound field in the desired sound field memory unit 31.

[0033] The optimization problem definition processing unit 12 performs processing to define an optimization problem for realizing the desired sound field defined by the desired sound field definition processing unit 11 .

[0034] The sound field control filter design processing unit 13 performs processing to design a sound field control filter using a proximity separation algorithm based on the optimization problem defined by the optimization problem definition processing unit 12, and stores the filter calculated by this processing in the filter memory unit 32.

[0035] The drive signal generation processing unit 14 performs a convolution operation on the acoustic signal AS input via the acoustic signal I / F 50 and the filter stored in the filter storage unit 32. The drive signal generation processing unit 14 then performs a convolution operation on the acoustic signal AS input via the acoustic signal I / F 50 and the filter stored in the filter storage unit 32. The drive signal generation processing unit 14 then performs a convolution operation on the acoustic signal AS input to the speakers SP1 to SP2 that form the circular speaker array SP. L The acoustic drive signal BS is generated with phase and amplitude controlled for each speaker, and the generated acoustic drive signal BS is output from the acoustic signal I / F 50 to the corresponding speaker SP1 to SP2. L The process of outputting to is performed.

[0036] (Example of operation) In the following, we will explain the basic technologies for area playback control executed by the playback control device 1, first explaining an example of a sound field reproduction technology using a circular speaker array based on the least squares method and an acoustic contrast maximization technology, and then explaining the filter gain suppression technology using a penalty term described in non-patent document 1.

[0037] (1) Sound field reproduction technology using a circular speaker array based on the least squares method In sound field reproduction technology using a circular speaker array based on the least-squares method, a control point is placed inside a circular speaker array in which multiple speakers are arranged on the same circumference. A filter is designed to control the amplitude and phase of each speaker based on the transmission characteristics from the speaker to the control point. By supplying the filtered acoustic drive signal BS to the speaker, the sound field observed at the control point is controlled to match the desired sound field.

[0038] A typical method for designing filters for sound field reproduction is the least squares method. Figure 5 shows an example of an observation system to explain the least squares method-based design method for filters for sound field reproduction. Here, the control points can be positioned arbitrarily depending on the sound field to be reproduced.

[0039]

number

[0040] Here, L indicates the number of speakers, M indicates the number of control points, ω indicates the angular frequency (ω=2πf), f indicates the frequency, and G(ω) indicates the amplitude of each speaker SP1 to SP2. L From each control point CP1 to CP M Transfer function G ml The l-th speaker SP that composes the transfer function matrix G(ω) is a transfer function matrix with M rows and L columns that stores the l mth control point CP m Transfer function G ml (ω) is given by the following formula:

[0041]

number

[0042]

number

[0043] Here, the superscript H represents the complex conjugate transpose. By solving the problem of minimizing the objective function J expressed in equation (3) for w(ω), the following sound field reproduction filter is obtained.

[0044]

number

[0045] (2) Acoustic contrast maximization technology As mentioned earlier, acoustic contrast maximization technology is a technology that maximizes the sound pressure ratio between the area (bright zone) BZ where arbitrarily set sound is presented and the area (dark zone) DZ where sound is suppressed for a speaker array.

[0046] FIG. 6 shows an example of an observation system used to explain the technique for maximizing acoustic contrast for the inside of a circular speaker array SP.

[0047] First, a desired sound field, that is, an area (bright zone) BZ where sound is presented and an area (dark zone) DZ where sound is suppressed, are arbitrarily set. L indicates each speaker of the circular speaker array SP, and CP 1B ~CP mB ~CP MB indicates a control point located in the Bright zone BZ, and CP 1D ~CP mD ~CP MD indicates a control point located in the Dark zone DZ. mBl (ω) is the lth speaker SP l to the m-th control point CP of the Bright zone BZ mD shows the transfer function up to G mDl (ω) is the lth speaker SP l to the m-th control point CP of the Bright zone BZ mD The transfer function up to

[0048] Circular speaker array SP speakers SP1 to SP L When driven by an acoustic drive signal BS, which is an acoustic signal AS with a filter w(ω) applied, the sound field observed in each area of ​​the bright zone BZ and dark zone DZ can be expressed by the following equation.

[0049]

number

[0050]

number

[0051] where p B (ω), p D (ω) represent the sound fields observed in the Bright zone BZ and Dark zone DZ, respectively, and G B (ω), G D (ω) is a transfer function matrix that stores the transfer functions from the speaker array SP to the bright zone BZ and the dark zone DZ. Also, the acoustic energy E B , E D can be expressed by the following formula:

[0052]

number

[0053]

number

[0054] where R B , R D is the spatial correlation matrix of the transfer function in each area (R=G H G). The acoustic contrast AC is E B and E D is obtained by the ratio of

[0055]

number

[0056] The acoustic contrast maximization technique is defined as the following optimization problem to maximize the acoustic contrast AC obtained from equation (9).

[0057]

number

[0058] (3) Filter gain suppression technology using penalty terms When designing a filter to control a sound field, depending on the filter design method, the solution obtained may become unstable and the filter gain may become excessively large, resulting in a filter that is difficult to reproduce using a speaker. If the filter gain is large, the input signal also becomes proportionally large, placing a large load on the speaker, making reproduction difficult and causing sound clipping. Here, the lth speaker SP at a certain angular frequency ω l The filter gain F corresponding to l gain (ω) is defined as follows:

[0059]

number

[0060] where w l (ω) is the lth speaker SP l The superscript * denotes the complex conjugate.

[0061] To address the problem of excessively large filter gains due to filter design methods, Non-Patent Document 1 derives a filter that controls the sound field while suppressing the filter gain by using a penalty term in the objective function used to derive the filter. In this case, the sum of squares of the filter coefficients is used as the penalty term to suppress the filter gain.

[0062] Consider a filter for sound field control when a penalty term is used, taking the derivation of a filter for sound field reproduction using the least squares method as an example. If the penalty term is used in the objective function of the above formula (3), it becomes as follows:

[0063]

number

[0064] where β(ω) is the regularization parameter and the loss term ||e|| 2 and the penalty term ||e(ω)|| 2 is a parameter that controls the relative weighting of . As with equation (4), by solving the minimization problem for w(ω), the following sound field control filter w(ω) can be obtained.

[0065]

number

[0066] Here, I represents an identity matrix with L rows and L columns, and L represents the number of speakers.

[0067] (4) Area Reproduction Control in an Embodiment of the Invention Below, we will explain the area reproduction control executed by the playback control device 1, taking into account (1) sound field reproduction technology using a circular speaker array based on the least squares method, (2) acoustic contrast maximization technology, and (3) filter gain suppression technology using a penalty term. Figure 4 is a flowchart showing the processing procedure and processing content of the area reproduction control executed by the playback control device 1.

[0068] (4-1) Definition of desired sound field A system administrator or a user sets a desired sound field to be reproduced in the input / output device 2. In response to this setting operation, the input / output device 2 generates desired sound field data DS necessary for defining the desired sound field to be reproduced, and the generated desired sound field data DS is sent to the playback control device 1.

[0069] In response to this, the control unit 10 of the playback control device 1 receives the desired sound field data DS from the input / output device 2 via the input / output I / F 40, and under the control of the desired sound field definition processing unit 11, in step S11, derives a desired sound field d=[d1, d2, ..., d M ] T Define

[0070] When defining a desired sound field, the positions and numbers of the bright zone, which is an area for reproducing a wavefront, and the dark zone, which is an area for suppressing sound, can be set arbitrarily within the inner area of ​​the circular speaker array SP. Furthermore, for the wavefront reproduced in the bright zone, it is possible to use a wavefront from a specific direction or a signal collected by a microphone array. Furthermore, the control unit 10 of the playback control device 1 stores the desired sound field d defined by the desired sound field definition processing unit 11 in the desired sound field storage unit 31.

[0071] (4-2) Definition of the optimization problem In the control unit 10 of the playback control device 1, when the desired sound field d is defined by the desired sound field definition processing unit 11, the optimization problem definition processing unit 12 then reads the desired sound field d from the desired sound field storage unit 31 under the control of the optimization problem definition processing unit 12 in step S12, and calculates the desired sound field d=[d1, d2, ..., d M ] T Using this, the optimization problem is defined as follows:

[0072]

number

[0073] Here, G is the number of control points CP1 to CP2 from the number of L speakers that make up the circular speaker array SP. M is a transfer function matrix with M rows and L columns that stores the transfer functions up to w=[w1, w2, …, w L ] T is a filter coefficient vector that stores the filter coefficients corresponding to each speaker. Also, λ1 and λ2 are the sum of squares of the l2 norm (|||| 2) and mixed l 1,2 norm (||·|| 1,2 ) and u=[u1,u2,…,u L ] T represents the reproduced sound field.

[0074] In this embodiment, the sum of squares (l2 norm) of the error between the desired sound field and the reproduced sound field is used to generate the bright zone BZ that reproduces the sound field and the dark zone DZ that suppresses sound, but it is also possible to replace this with a method in which the weight ratio between minimizing the error with the desired sound field in the bright zone and minimizing the acoustic energy in the dark zone can be controlled by parameters.

[0075] (4-3) Design of filters for sound field control Next, in step S13, the control unit 10 of the playback control device 1, under the control of the sound field control filter design processing unit 13, calculates a filter for sound field control by solving the optimization problem defined by the optimization problem definition processing unit 12 using a proximity separation algorithm.

[0076]

number

[0077] where p is the dual variable and h*(·) denotes the convex conjugate function of h(·).

[0078] Next, the sound field control filter design processing unit 13 generates the following proximity separation algorithm for the optimization problem shown in the rewritten equation (15), based on the fixed point condition that the subdifferentials with respect to the primal variable w and the dual variable p include 0.

[0079]

number

[0080]

number

[0081] where k is the number of updates, T max is the maximum number of updates. In this algorithm, the number of updates k is the maximum number of updates T max The algorithm is designed to stop when it exceeds this value. By using the above algorithm, the filter w for sound field control is calculated.

[0082] (4-4) Applying filter coefficients to input acoustic signals When the calculation and storage process of the sound field control filter is completed, the control unit 10 of the playback control device 1 thereafter executes the sound playback process for the specific area as follows.

[0083] That is, the control unit 10 of the playback control device 1 receives an acoustic signal AS output from a sound source (not shown) via the acoustic signal I / F 50. At this time, if the acoustic signal AS is an analog signal, it is converted into a digital signal by the acoustic signal I / F 50. Next, under the control of the drive signal generation processing unit 14, the control unit 10 of the playback control device 1 performs a convolution operation on the acoustic signal AS received via the acoustic signal I / F 50 and the filter w stored in the filter data storage unit 32 in step S14, thereby generating a filter w for each of the speakers SP1 to SP2 to which the filter w has been applied. L The generated acoustic signal is converted into an analog signal by the acoustic signal I / F 50, and then output as an acoustic drive signal BS to the corresponding speakers SP1 to SP2. L is output to.

[0084] (effect) As described above, the playback control device 1 according to an embodiment of the present invention includes a plurality of speakers SP1 to SP L This is a device for area reproduction using a circular speaker array SP arranged inward in a circle.

[0085] The sound field definition processing unit 11 defines a desired sound field d from the input desired sound field data DS. When defining the desired sound field, the positions and numbers of the Bright zone, which is an area where the wavefront is reproduced, and the Dark zone, which is an area where sound is suppressed, can be set arbitrarily within the inner area of ​​the circular speaker array SP.

[0086] The optimization problem definition processing unit 12 defines an optimization problem using the desired sound field d. At this time, the optimization problem includes the sum-of-squares l2 norm of the filter coefficient vector and a mixed l2 norm that evaluates whether the sound field in the area to be reproduced has sparsity. 1,2 The norm is added to the objective function as a sum of operators.

[0087] The sound field control filter design processing unit 13 calculates the filter W for sound field control by solving the defined optimization problem using a proximity separation algorithm.

[0088] The drive signal generation processing unit 14 performs a convolution operation on the input acoustic signal AS and the calculated sound field control filter to generate acoustic drive signals BS for each speaker of the circular speaker array SP, and outputs each of the generated acoustic drive signals BS to the corresponding speakers SP1 to SP2. L By supplying the signal to the

[0089] That is, in one embodiment, when designing a filter for sound field control, the sum of squares of the filter coefficients (l2 norm) is added as a penalty term to the objective function for determining a filter for sound field reproduction by the least squares method, and further, a mixed l2 norm is used to evaluate the sparsity under the assumption that the sound field in the area to be reproduced has sparsity. 1,2 The norm is added as an operator.

[0090] Therefore, each speaker SP1 to SP L This makes it possible to reproduce a sound field that reproduces the desired wavefront in the bright zone while suppressing the gain added to the dark zone and suppressing sound leakage into the dark zone.

[0091] [Other embodiments] It should be noted that the present invention is not limited to the above-described embodiment. For example, in one embodiment, the optimization problem definition process, sound field control filter design process, and drive signal generation process executed by the playback control device 1 are all implemented by having a hardware processor (CPU) execute programs. However, some or all of these functions may be implemented using an integrated circuit configured for a specific application, such as an ASIC (Application Specific Integrated Circuit) or a DSP (Digital Signal Processor).

[0092] In short, this invention is not limited to the above-described embodiments, and in the implementation stage, the components can be modified and embodied without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0093] SP1~SP L ...speaker CP1~CP M …control points 1...Playback control device 2...Input device 10...Control unit 11...Desired sound field definition processing unit 12...Optimization problem definition processing section 13...Sound field control filter design processing section 14...Drive signal generation processing unit 20...Program memory section 30...Data storage unit 31...Desired sound field storage section 32...Filter memory section 40...Input / output interface 50...Acoustic signal I / F

Claims

1. A playback control device for area playback of sound inside a circular speaker array using a circular speaker array in which a plurality of speakers are arranged inward in a circular shape, a desired sound field definition processing unit that defines a desired sound field from input desired sound field data; an optimization problem definition processing unit that defines an optimization problem for obtaining the defined desired sound field; a sound field control filter design processing unit that designs a filter for sound field control using a proximity separation algorithm based on the defined optimization problem; a drive signal generation processing unit that applies the filter to an input acoustic signal to generate a drive signal to be input to each speaker of the circular speaker array; Equipped with The optimization problem definition processing unit defines, as the optimization problem, an optimization problem for reproducing the desired sound field, by introducing a sum-of-squares l 2 norm of filter coefficients to suppress speaker gain, and, under the assumption that the reproduced sound field is sparse, by introducing a mixed l 1,2 norm of the reproduced sound field.

2. The playback control device according to claim 1 , wherein the desired sound field definition processing unit defines the desired sound field as a desired sound field that is comprised of an area that reproduces a wavefront and an area that suppresses sound inside the circular speaker array.

3. The playback control device according to claim 1 , wherein the drive signal generation processing unit generates the drive signal by performing a convolution operation on the acoustic signal and the filter.

4. A playback control method for area-reproducing sound inside a circular speaker array using a circular speaker array in which a plurality of speakers are arranged inward in a circular shape, comprising: defining a desired sound field from the desired sound field data; defining an optimization problem for obtaining the desired sound field; designing a filter for sound field control using a proximity separation algorithm based on the optimization problem; generating a driving signal to be input to each speaker of the circular speaker array by applying the filter to an input acoustic signal; and The step of defining the optimization problem introduces the sum-of-squares l 2 norm of filter coefficients to suppress speaker gain for the optimization problem of reproducing the desired sound field, and defines an optimization problem that introduces the mixed l 1,2 norm of the reproduced sound field under the assumption that the reproduced sound field is sparse.

5. A program that causes a processor included in the playback control device to execute the processes performed by the processing units included in the playback control device according to any one of claims 1 to 3.

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