Stereophonic sound reproducing apparatus

Abstract

To provide a stereophonic sound reproducing technique with high robustness against movement of a listener and capable of performing control with a small dynamic range loss.SOLUTION: A stereophonic sound reproducing device includes a first speaker array 2 composed of two or more speakers arranged on a sagittal plane on the right side of a listener, a second speaker array 4 composed of two or more speakers arranged on a sagittal plane on the left side of the listener, a first signal processing unit 1 for performing crosstalk cancellation processing for canceling sound reaching the left ear of the listener from the first speaker array 2 and generating a first post-processing signal, and a second signal processing unit 3 for performing crosstalk cancellation processing for canceling sound reaching the right ear of the listener from the second speaker array 4 and generating a second post-processing signal. The first speaker array 2 emits a sound based on the first processed signal, and the second speaker array 4 emits a sound based on the second processed signal.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The disclosed technology relates to a stereophonic sound reproduction technology. [Background technology]

[0002] One stereophonic sound reproduction technology that utilizes the characteristics of hearing is the transaural system, which reproduces binaurally recorded sound signals near the listener's ears using two speakers arranged in a stereophonic configuration (horizontal arrangement) on the listener's horizontal plane.

[0003] The control performance of a transaural system is evaluated using two indicators: the amount of crosstalk cancellation (the amount of suppression of the acoustic signal reaching the right ear from the left channel speaker, and the amount of suppression of the acoustic signal reaching the left ear from the right channel speaker) and the flatness of the frequency characteristics of the reproduced acoustic signal. Furthermore, a common speaker placement method has traditionally been a stereo placement (horizontal placement) in which two speakers are lined up horizontally on the listener's horizontal plane (see, for example, Patent Document 1).

[0004] However, this type of arrangement is very sensitive to changes in the listener's position, and even a slight movement of the listener from the position assumed when the controller was designed (the sweet spot for the stereophonic sound reproduction device) can result in the desired control effect being lost, resulting in a problem of low robustness.

[0005] Previous efforts to improve the robustness of transaural systems have involved approaches based on geometric conditions, such as the Stereo-Dipole method, which reduces the distance between the two speakers in the horizontal arrangement described above. However, these have had problems such as the fact that robustness can only be improved in the audio signal band (a few kHz or less) and that the dynamic range of the reproduced audio signal is lost.

[0006] In our prior art (see, for example, Patent Document 2), we considered the physical causes of deterioration in the control effect as the listener moves, and discovered that the main cause is the change in the direction of the sound propagation path length from the speaker to the listener's ear when the listener moves.We discovered that to fundamentally eliminate this cause, it is sufficient to line up the two speakers vertically on the listener's median plane (vertical arrangement), rather than the conventional horizontal arrangement.

[0007] However, when two speakers are placed on the median plane, the four acoustic transfer functions in the playback system are almost identical to each other, which leaves the problem of dynamic range loss.

[0008] The problem of dynamic range loss can be solved to some extent by arranging the two speakers vertically (vertical arrangement) on the same sagittal or transverse plane rather than on the median plane of the listener. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-57699 [Patent Document 2] Japanese Patent Application Publication No. 2023-121744 Summary of the Invention [Problem to be solved by the invention]

[0010] However, in such a configuration where two speakers are arranged on the same sagittal or transverse plane, if the two speakers are arranged, for example, to the right of the listener, it has been found that the control performance for the reproduction of the left channel of the binaural signal is degraded compared to the control performance for the reproduction of the right channel of the binaural signal.

[0011] The disclosed technology aims to provide a stereophonic sound reproduction device that is highly robust against listener movement and capable of control with little loss of dynamic range, both when reproducing the right channel of a binaural signal and when reproducing the left channel of a binaural signal. [Means for solving the problem]

[0012] A stereophonic sound reproduction device according to one aspect of the present invention includes a first speaker array consisting of two or more speakers arranged on a sagittal plane to the right of a listener, a second speaker array consisting of two or more speakers arranged on a sagittal plane to the left of the listener, a first signal processing unit that performs crosstalk cancellation processing to cancel out sounds reaching the listener's left ear from the first speaker array and generate a first processed signal, and a second signal processing unit that performs crosstalk cancellation processing to cancel out sounds reaching the listener's right ear from the second speaker array and generate a second processed signal. The first speaker array emits sounds based on the first processed signal, and the second speaker array emits sounds based on the second processed signal.

[0013] A stereophonic sound reproduction device according to one embodiment of the present invention includes a first speaker array consisting of two or more speakers located to the right of a listener and in a cross section of the listener, a second speaker array consisting of two or more speakers located to the left of the listener and in a cross section of the listener, a first signal processing unit that performs crosstalk cancellation processing to cancel out sounds reaching the listener's left ear from the first speaker array and generates a first processed signal, and a second signal processing unit that performs crosstalk cancellation processing to cancel out sounds reaching the listener's right ear from the second speaker array and generates a second processed signal. The first speaker array emits sounds based on the first processed signal, and the second speaker array emits sounds based on the second processed signal. [Effects of the Invention]

[0014] In both the reproduction of the right channel of the binaural signal and the reproduction of the left channel of the binaural signal, control with high robustness against listener movement and small loss of dynamic range is possible. [Brief explanation of the drawings]

[0015] [Figure 1A] FIG. 1A is a diagram for explaining the theoretical background. [Figure 1B] FIG. 1B is a diagram for explaining the theoretical background. [Figure 2A] FIG. 2A is a diagram for explaining the theoretical background and the names of physical reference planes. [Figure 2B] FIG. 2B is a diagram for explaining the theoretical background and the names of the physical reference planes. [Figure 3A] FIG. 3A is a diagram for explaining the theoretical background and the names of physical reference planes. [Figure 3B] FIG. 3B is a diagram for explaining the theoretical background and the names of the physical reference planes. [Figure 4] FIG. 4 is a diagram illustrating an example of the functional configuration of a stereophonic sound reproduction device. [Figure 5A] FIG. 5A is a diagram showing the simulation results. [Figure 5B] FIG. 5B is a diagram showing the simulation results. [Figure 5C] FIG. 5C is a diagram showing the simulation results. [Figure 5D] FIG. 5D is a diagram showing the simulation results. [Figure 6A] FIG. 6A is a diagram showing the simulation results. [Figure 6B] FIG. 6B is a diagram showing the simulation results. [Figure 6C] FIG. 6C is a diagram showing the simulation results. [Figure 7A]FIG. 7A is a diagram showing the simulation results. [Figure 7B] FIG. 7B is a diagram showing the simulation results. [Figure 7C] FIG. 7C is a diagram showing the simulation results. [Figure 7D] FIG. 7D is a diagram showing the simulation results. [Figure 8A] FIG. 8A is a diagram showing the simulation results. [Figure 8B] FIG. 8B is a diagram showing the simulation results. [Figure 8C] FIG. 8C is a diagram showing the simulation results. [Figure 9A] FIG. 9A is a diagram showing the simulation results. [Figure 9B] FIG. 9B is a diagram showing the simulation results. [Figure 9C] FIG. 9C is a diagram showing the simulation results. [Figure 9D] FIG. 9D is a diagram showing the simulation results. [Figure 10A] FIG. 10A is a diagram showing the simulation results. [Figure 10B] FIG. 10B is a diagram showing the simulation results. [Figure 10C] FIG. 10C is a diagram showing the simulation results. [Figure 11A] FIG. 11A is a diagram showing the simulation results. [Figure 11B] FIG. 11B is a diagram showing the simulation results. [Figure 11C] FIG. 11C is a diagram showing the simulation results. [Figure 11D] FIG. 11D is a diagram showing the simulation results. [Figure 12A] FIG. 12A is a diagram showing the simulation results. [Figure 12B]FIG. 12B is a diagram showing the simulation results. [Figure 12C] FIG. 12C is a diagram showing the simulation results. [Figure 13A] FIG. 13A is a diagram showing the simulation results. [Figure 13B] FIG. 13B is a diagram showing the simulation results. [Figure 13C] FIG. 13C is a diagram showing the simulation results. [Figure 13D] FIG. 13D is a diagram showing the simulation results. [Figure 14A] FIG. 14A is a diagram showing the simulation results. [Figure 14B] FIG. 14B is a diagram showing the simulation results. [Figure 14C] FIG. 14C is a diagram showing the simulation results. [Figure 15A] FIG. 15A is a diagram showing the simulation results. [Figure 15B] FIG. 15B is a diagram showing the simulation results. [Figure 15C] FIG. 15C is a diagram showing the simulation results. [Figure 15D] FIG. 15D is a diagram showing the simulation results. [Figure 16A] FIG. 16A is a diagram showing the simulation results. [Figure 16B] FIG. 16B is a diagram showing the simulation results. [Figure 16C] FIG. 16C is a diagram showing the simulation results. [Figure 17] FIG. 17 is a diagram illustrating an example of a functional configuration of a computer. [Figure 18] FIG. 18 is a diagram showing an example of a processing procedure of the stereophonic sound reproduction method. DETAILED DESCRIPTION OF THE INVENTION

[0016] [Theoretical background] In a horizontal arrangement of two speakers (as shown in FIG. 1B) used in a conventional transaural system (a system having the functional configuration shown in FIG. 1A), when a listener's head moves to the right, the length of the acoustic propagation path from the left channel speaker to the listener's right ear increases, and the length of the acoustic propagation path from the right channel speaker to the listener's right ear decreases. Due to the difference in the direction of increase and decrease in these lengths, the phase of the acoustic signal output from the left channel speaker that reaches the right ear is delayed, and the phase of the acoustic signal output from the right channel speaker that reaches the right ear is advanced. If the phases of the two signals change in opposite directions, the acoustic signal reproduced at the listener's right ear, which is a combination of the two signals, will no longer maintain the desired control of the transaural system.

[0017] To generalize this, even a slight movement of the listener can significantly change the phase shift in each sound propagation path, which leads to a deterioration in the control effect. In our prior art (see, for example, Patent Document 2), we discovered that to fundamentally solve this problem, it is necessary to geometrically arrange two speakers so that the change direction of the sound propagation path length from each speaker is the same as the movement of the listener's head. As an example of such an arrangement, we proposed an arrangement (vertical arrangement) in which the speakers are arranged vertically on the listener's median plane, as shown in Figure 2A.

[0018] However, when two speakers are placed on the median plane, the four acoustic transfer functions in the playback system are almost identical to each other, which means that a speaker with a steep radiation directivity characteristic is required to obtain a controller, and if a speaker with a gentle radiation directivity characteristic is used, the problem of dynamic range loss remains.

[0019] To solve this problem, it is theoretically advantageous to arrange the two speakers vertically (vertical arrangement) on the same sagittal plane (as shown in Figure 2B) rather than on the median plane of the listener, as a method for arranging the two speakers so that the four acoustic transfer functions in the playback system are sufficiently different from one another. This eliminates the need for speakers with steep radiation directivity characteristics and solves the problem of dynamic range loss.

[0020] However, it has been discovered that placing two loudspeakers in the same sagittal plane as the listener has other drawbacks. Specifically, when the loudspeakers are placed in the sagittal plane to the listener's right (as shown in Figure 2B), the control performance for the left channel of the binaural signal is degraded compared to the control performance for the right channel of the binaural signal. This is because both loudspeakers used in the transaural system are placed in the shadow of the listener's left ear. Similarly, when the loudspeakers are placed in the sagittal plane to the listener's left, the same control performance degradation occurs, except that the left-right relationship is reversed.

[0021] To solve this problem, we found that in addition to the two speakers located on the right side of the listener in the sagittal / transverse plane, two speakers used as a transaural system could be placed separately on the left side of the listener in the sagittal / transverse plane. That is, by creating two separate speaker / transaural system control systems for the right channel of the binaural signal and two separate speaker / transaural system control systems for the left channel of the binaural signal, as shown in Figure 3AB, the former two speakers were placed on the right side of the listener in the sagittal / transverse plane, and the latter two speakers were placed on the left side of the listener in the sagittal / transverse plane. This enabled us to achieve equivalent control performance for the playback of both the left and right channels of the binaural signal.

[0022] The new transaural system, which combines the above methods, can guarantee the robustness of 3D sound reproduction by maintaining crosstalk cancellation and frequency flatness even when the listener's head position changes, and it also reduces the loss of dynamic range. This results in a clearer sense of sound localization and a more robust 3D sound reproduction effect than conventional transaural systems. Furthermore, because such control effects can be achieved over a wide frequency range, including the music signal band (10 kHz and above), it is expected that the system will be widely applied as a 3D sound reproduction device.

[0023] [Embodiment] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings, in which like reference numerals are used to designate like components having the same functions, and redundant description will be omitted.

[0024] As shown in Fig. 4, the stereophonic sound reproduction device includes a first signal processing unit 1, a first speaker row 2, a second signal processing unit 3, and a second speaker row 4. As shown in Fig. 18, the stereophonic sound reproduction method is realized, for example, by steps S1, S2, S3, and S4 described below.

[0025] Figures 2 and 3 are also diagrams used to explain the physical reference planes and their names related to speaker placement. The median plane is the plane that cuts the body symmetrically from left to right. The sagittal plane is the general term for planes parallel to the median plane. The transverse plane is the plane that cuts the body symmetrically from front to back.

[0026] In the following, an example will be described in which the first speaker row 2 is composed of two speakers, a first speaker 21 and a second speaker 22, and the second speaker row 4 is composed of two speakers, a third speaker 41 and a fourth speaker 42.

[0027] <Speaker arrangement 1> As shown in Fig. 3A, the first speaker 21 and the second speaker 22 are, for example, arranged on the sagittal plane to the right of the listener. The third speaker 41 and the fourth speaker 42 are arranged on the sagittal plane to the left of the listener. More specifically, in Fig. 3A, the first speaker 21 and the second speaker 22 are arranged side by side in the vertical direction on the sagittal plane to the right of the listener. The third speaker 41 and the fourth speaker 42 are arranged side by side in the vertical direction on the sagittal plane to the left of the listener.

[0028] As in this example, the first speaker array 2 may be composed of two or more speakers arranged on the sagittal plane to the right of the listener, and the second speaker array 4 may be composed of two or more speakers arranged on the sagittal plane to the left of the listener.

[0029] The azimuth angle of the first speaker row 2 may be a predetermined angle between 0 degrees and 90 degrees, or between 0 degrees and 180 degrees. The azimuth angle of the second speaker row 4 may be a predetermined angle between -90 degrees and 0 degrees, or between -180 degrees and 0 degrees.

[0030] The absolute values ​​of the azimuth angles of the first speaker array 2 and the second speaker array 4 may be the same or different. In other words, the first speaker array 2 and the second speaker array 4 may be arranged symmetrically or asymmetrically with respect to the median plane of the listener.

[0031] Here, the azimuth angles of the first speaker row 2 and the second speaker row 4 are expressed as angles (φ in FIG. 3A) clockwise with respect to the front direction of the listener.

[0032] The elevation / depression angle (β in FIG. 3A) of first speaker 21 is a predetermined angle between −90 degrees and 90 degrees, and the elevation / depression angle of second speaker 22 is a predetermined angle between −90 degrees and 90 degrees.

[0033] The absolute values ​​of the elevation / depression angles of the first speaker 21 and the second speaker 22 may be the same or different. In other words, the first speaker 21 and the second speaker 22 may be arranged symmetrically or asymmetrically with respect to a horizontal plane including the position of the listener.

[0034] Similarly, the absolute values ​​of the elevation / depression angles of the third speaker 41 and the fourth speaker 42 may be the same or different. In other words, the third speaker 41 and the fourth speaker 42 may be arranged symmetrically or asymmetrically with respect to a horizontal plane including the position of the listener.

[0035] <Speaker arrangement type 2> As shown in Figure 3B, the first speaker 21 and the second speaker 22 may be disposed on the right side of the listener and on a cross section of the listener. The third speaker 41 and the fourth speaker 42 may be disposed on the left side of the listener and on a cross section of the listener. More specifically, as illustrated in Figure 3B, the first speaker 21 and the second speaker 22 may be disposed on the right side of the listener and on a cross section of the listener, side by side in the vertical direction. The third speaker 41 and the fourth speaker 42 may be disposed on the left side of the listener and on a cross section of the listener, side by side in the vertical direction.

[0036] As in this example, two or more speakers constituting the first speaker row 2 may be arranged on the right side of the listener in cross section, and two or more speakers constituting the second speaker row 4 may be arranged on the left side of the listener in cross section.

[0037] The elevation / depression angle (θ in FIG. 3B) of first speaker 21 is a predetermined angle between −90 degrees and 90 degrees, and the elevation / depression angle of second speaker 22 is a predetermined angle between −90 degrees and 90 degrees.

[0038] The absolute values ​​of the elevation / depression angles of the first speaker 21 and the second speaker 22 may be the same or different. In other words, the first speaker 21 and the second speaker 22 may be arranged symmetrically or asymmetrically with respect to a horizontal plane including the position of the listener.

[0039] Similarly, the absolute values ​​of the elevation / depression angles of the third speaker 41 and the fourth speaker 42 may be the same or different. In other words, the third speaker 41 and the fourth speaker 42 may be arranged symmetrically or asymmetrically with respect to a horizontal plane including the position of the listener.

[0040] 3A and 3B, in a three-dimensional space with the center of the listener's head as the origin, the listener faces in the positive direction of the y-axis, and ears B1 and B2 of the listener are located on a plane including the x-axis and z-axis.

[0041] The listener's median plane in Figures 3A and 3B is the plane containing the y-axis and z-axis. The listener's sagittal plane in Figures 3A and 3B is the plane parallel to the median plane, which is the plane containing the y-axis and z-axis. The listener's transverse plane in Figures 3A and 3B is the plane containing the x-axis and z-axis.

[0042] <First signal processing unit 1> An input signal d1 is input to the first signal processing unit 1. The input signal d1 is, for example, a right channel signal of a binaural signal. The input signal d1 may be an acoustic signal or an audio signal other than a binaural signal.

[0043] The first signal processing unit 1 performs crosstalk cancellation processing to cancel out sounds reaching the left ear of the listener from the first speaker array 2, and generates first processed signals (step S1). In this example, the first signal processing unit 1 performs crosstalk cancellation processing to cancel out sounds reaching the left ear of the listener from the first speaker 21 and the second speaker 22, and generates first processed signals v1 and v2.

[0044] In addition to the crosstalk cancellation process, the first signal processing unit 1 may also perform a process to compensate for the acoustic transfer characteristics (direct components) from the first speaker 21 and the second speaker 22 to the right ear, in other words, an equalization process to flatten the frequency characteristics.

[0045] In order to perform the crosstalk cancellation process and the equalization process, the first signal processing unit 1 performs, for example, a transfer function G 11 ,G 21 The transfer function G is determined by the control filter vector GR, where α=1, and satisfies the formula (1). 11 ,G 21 When the following processing using the above formula is performed, crosstalk cancellation processing and equalization processing are performed. 11 ,G 21 When the following process using the formula (1) is performed, the crosstalk cancellation process is performed. α and formula (1) will be described later.

[0046] The first signal processing unit 1 calculates a transfer function G 11 The processed signal is designated as a first processed signal v1.

[0047] The first signal processing unit 1 also calculates a transfer function G 21 The processed signal is designated as a first processed signal v2.

[0048] G 11 ,G 21 is a transfer function that is an element of the control filter vector GR. The control filter vector GR is assumed to be calculated in advance based on a predetermined transfer function matrix H. The three-dimensional sound reproduction device may further include a control filter vector calculation unit 5, shown by a dashed line in FIG. 4, that calculates the control filter vector GR. The processing of the control filter vector calculation unit 5 will be described later.

[0049] The first processed signals v1 and v2 are output to the first speaker 21 and the second speaker 22. In this example, the first processed signal v1 is output to the first speaker 21, and the first processed signal v2 is output to the second speaker 22.

[0050] <Second signal processing unit 3> An input signal d2 is input to the second signal processing unit 3. The input signal d2 is, for example, a left channel signal of a binaural signal. The input signal d2 may be an acoustic signal or an audio signal other than a binaural signal.

[0051] The second signal processing unit 3 performs crosstalk cancellation processing to cancel out sounds reaching the right ear of the listener from the second speaker row 4, and generates second processed signals (step S2). In this example, the second signal processing unit 3 performs crosstalk cancellation processing to cancel out sounds reaching the right ear of the listener from the third speaker 41 and the fourth speaker 42, and generates second processed signals v3 and v4.

[0052] In addition to the crosstalk cancellation process, the second signal processing unit 3 may also perform a process to compensate for the acoustic transfer characteristics (direct components) from the third speaker 41 and the fourth speaker 42 to the left ear, in other words, an equalization process to flatten the frequency characteristics.

[0053] In order to perform the crosstalk cancellation process and the equalization process, the second signal processing unit 3 performs, for example, a transfer function G 32 ,G 42 The transfer function G is determined by the control filter vector GL, where α=1, and satisfies the formula (2). 32 ,G 42 When the following processing using the above formula is performed, crosstalk cancellation processing and equalization processing are performed. 32 ,G 42 When the following process using the formula (2) is performed, the crosstalk cancellation process is performed. α and formula (2) will be described later.

[0054] The second signal processing unit 3 calculates a transfer function G 32 The processed signal is designated as a second processed signal v3.

[0055] The second signal processing unit 3 also calculates a transfer function G 42 The processed signal is designated as a second processed signal v4.

[0056] G 32 ,G 42 is a transfer function that is an element of the control filter vector GL. The control filter vector GL is assumed to be calculated in advance based on a predetermined transfer function matrix H. The stereophonic sound reproduction device may further include a control filter vector calculation unit 6, shown by a dashed line in FIG. 4, that calculates the control filter vector GL. The processing of the control filter vector calculation unit 6 will be described later.

[0057] The second processed signals v3 and v4 are output to the third speaker 41 and the fourth speaker 42. In this example, the second processed signal v3 is output to the third speaker 41, and the second processed signal v4 is output to the fourth speaker 42.

[0058] <First speaker 21 and second speaker 22> The first processed signals v1 and v2 are input to the first speaker 21 and the second speaker 22.

[0059] The first speaker 21 and the second speaker 22 emit sounds based on the first processed signals v1 and v2 (step S3). In this example, the first speaker 21 emits a sound based on the first processed signal v1, and the second speaker 22 emits a sound based on the first processed signal v2.

[0060] In this example, the first speaker row 2 emits a sound based on the first processed signal.

[0061] <Third speaker 41 and fourth speaker 42> The third speaker 41 and the fourth speaker 42 receive the second processed signals v3 and v4.

[0062] The third speaker 41 and the fourth speaker 42 emit sounds based on the second processed signals v3 and v4 (step S4). In this example, the third speaker 41 emits a sound based on the second processed signal v3, and the fourth speaker 42 emits a sound based on the second processed signal v4.

[0063] In this example, the second speaker row 4 emits a sound based on the second processed signal.

[0064] <Control filter vector calculation unit 5> If the stereophonic sound reproducing device includes a control filter vector calculation unit 5, the control filter vector calculation unit 5 calculates a control filter vector GR={G 11 ,G 21} T is calculated (step S5), where α is a number greater than 0. For example, α=1.

number

[0065] <Control filter vector calculation unit 6> If the stereophonic sound reproducing device includes a control filter vector calculation unit 6, the control filter vector calculation unit 6 calculates a control filter vector GL={G 32 ,G 42} T is calculated (step S6), where α is a number greater than 0. For example, α=1.

number

[0066] As in the embodiment of the stereophonic sound reproduction device, two speakers are placed on the sagittal / transverse plane to the right of the listener, and two other speakers are placed on the sagittal / transverse plane to the left of the listener, and the speaker row placed on the right of the listener is used to reproduce the right channel of the binaural signals, and the speaker row placed on the left of the listener is used to reproduce the left channel of the binaural signals.This makes it possible to achieve control that is highly robust against listener movement and with little loss of dynamic range, for both the reproduction of the right channel of the binaural signals and the reproduction of the left channel of the binaural signals.

[0067] [Simulation Results] Below, the results of a simulation using actual measurements of a dummy head as the predetermined transfer function matrix H are shown.

[0068] The control filter was designed using the time domain design method (Wiener Filter Approach) using the least squares method. The number of taps of the control filter was Ng = 512. The distance between the dummy head and the speaker was L = 1.4 m, and the sampling frequency was 44100 Hz.

[0069] Under the above simulation conditions, when d1(n) = δ(n), d2(n) = 0 are used as the input signal (when attempting to reproduce the right channel of the binaural signal), the frequency characteristics of the synthesized signal when the listener is at various positions in the horizontal direction (x-axis direction) are shown in Figures 5ABCD and 6ABC.

[0070] 5ABCD and 6ABC, the horizontal axis represents frequency and the vertical axis represents relative level. In Figures 5ABCD and 6ABC, the solid lines represent direct components, which are signals to be reproduced, and the wavy lines represent crosstalk components, which are signals to be eliminated.

[0071] FIG. 5A is a graph showing a comparison of the frequency characteristics of the synthesized signal when two speakers are arranged horizontally as in the background art, and the listener is located at the origin position (x=0 cm) and when the listener is located 5 cm laterally shifted from the origin position (x=5 cm).

[0072] From Figure 5A, it can be seen that when two speakers are arranged horizontally as in the background art, if the listener moves 5 cm horizontally, the flatness of the direct component deteriorates and the crosstalk component increases, resulting in a deterioration in control performance.

[0073] Figure 5B shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=30°) as in the background art, and the listener is located at the origin (x=0 cm) and at a position 5 cm laterally shifted from the origin (x=5 cm).

[0074] Figure 5C shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=60°) as in the background art, and the listener is located at the origin (x=0 cm) and at a position 5 cm laterally shifted from the origin (x=5 cm).

[0075] Figure 5BC shows that when two speakers are placed on the right sagittal plane (φ=30° or 60°) as in the background art, even if the listener moves 5 cm laterally, the flatness of the direct component is maintained to a certain extent, the crosstalk component is kept small, and control performance is maintained. However, it can be seen that the playback level of the direct component is reduced and the dynamic range is lost whether the listener is at the origin position (x=0 cm) or at a position shifted 5 cm laterally (x=5 cm).

[0076] Figure 5D shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) as in the background art, with the listener at the origin position (x=0 cm) and when the listener is positioned 5 cm laterally away from the origin position (x=5 cm).

[0077] Figure 5D shows that when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) as in the background art, even if the listener moves 5 cm laterally, the flatness of the direct component is maintained to a certain extent, the crosstalk component is kept small, and control performance is maintained. However, it can be seen that the playback level of the direct component is reduced and the dynamic range is lost whether the listener is at the origin position (x=0 cm) or at a position shifted 5 cm laterally (x=5 cm).

[0078] FIG. 6A shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=30°) and two separate speakers are placed on the left sagittal plane (φ=-30°), as in the embodiment, and the listener is at the origin position (x=0 cm) and when the listener is at a position 5 cm shifted laterally from the origin position (x=5 cm).

[0079] FIG. 6B shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=60°) and two separate speakers are placed on the left sagittal plane (φ=-60°), as in the embodiment, and the listener is at the origin position (x=0 cm) and when the listener is at a position 5 cm shifted laterally from the origin position (x=5 cm).

[0080] Figure 6AB shows that when two speakers are placed on the right sagittal plane (φ=30° or 60°) and two separate speakers are placed on the left sagittal plane (φ=-30° or -60°), even if the listener moves 5 cm horizontally, the flatness of the direct component is maintained to a certain extent, the crosstalk component is also maintained to a small extent, and control performance is maintained. Furthermore, whether the listener is at the origin position (x=0 cm) or at a position shifted 5 cm horizontally (x=5 cm), the playback level of the direct component is maintained to a certain extent, and the dynamic range is also maintained to a certain extent.

[0081] FIG. 6C shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) and two separate speakers are placed on the left sagittal plane (φ=-90°, i.e., on the transverse plane), as in the embodiment, and the listener is at the origin position (x=0 cm) and when the listener is at a position 5 cm laterally shifted from the origin position (x=5 cm).

[0082] Figure 6C shows that when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) and two separate speakers are placed on the left sagittal plane (φ=-90°, i.e., on the transverse plane), even if the listener moves 5 cm horizontally, the flatness of the direct component is maintained to a certain extent, the crosstalk component is also maintained to a small extent, and control performance is maintained. Furthermore, whether the listener is at the origin position (x=0 cm) or at a position shifted 5 cm horizontally (x=5 cm), the playback level of the direct component and the dynamic range are also maintained to a certain extent.

[0083] Under the above simulation conditions, when d1(n) = 0 and d2(n) = δ(n) are used as the input signals (when attempting to reproduce the left channel of the binaural signal), the frequency characteristics of the synthesized signal when the listener is at various positions in the horizontal direction (x-axis direction) are shown in Figures 7ABCD and 8ABC.

[0084] 7ABCD and 8ABC, the horizontal axis represents frequency and the vertical axis represents relative level. In Figures 7ABCD and 8ABC, the solid lines represent direct components, which are signals to be reproduced, and the wavy lines represent crosstalk components, which are signals to be eliminated.

[0085] FIG. 7A is a graph showing a comparison of the frequency characteristics of the synthesized signal when two speakers are arranged horizontally as in the background art, and the listener is located at the origin position (x=0 cm) and when the listener is located 5 cm laterally shifted from the origin position (x=5 cm).

[0086] From Figure 7A, it can be seen that when two speakers are arranged horizontally as in the background art, if the listener moves 5 cm horizontally, the flatness of the direct component deteriorates and the crosstalk component increases, resulting in a deterioration in control performance.

[0087] Figure 7B shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=30°) as in the background art, and the listener is located at the origin (x=0 cm) and at a position 5 cm laterally shifted from the origin (x=5 cm).

[0088] FIG. 7C shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=60°) as in the background art, and the listener is located at the origin (x=0 cm) and at a position 5 cm laterally shifted from the origin (x=5 cm).

[0089] Figure 7BC shows that when two speakers are placed on the right sagittal plane (φ=30° or 60°) as in the background art, even if the listener is at the origin position (x=0 cm), moving 5 cm horizontally causes the flatness of the direct component to deteriorate and the crosstalk component to increase, resulting in a deterioration in control performance. Furthermore, it can be seen that the reproduction level of the direct component becomes smaller, resulting in a loss of dynamic range.

[0090] FIG. 7D shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) as in the background art, and the listener is located at the origin (x=0 cm) and at a position 5 cm laterally shifted from the origin (x=5 cm).

[0091] Figure 7D shows that when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) as in the background art, even if the listener is at the origin position (x=0 cm), even if the listener moves 5 cm laterally, the flatness of the direct component deteriorates and the crosstalk component increases, resulting in a deterioration of control performance. Furthermore, it can be seen that the reproduction level of the direct component decreases, resulting in a loss of dynamic range.

[0092] FIG. 8A shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=30°) and two separate speakers are placed on the left sagittal plane (φ=-30°), as in the embodiment, and the listener is at the origin position (x=0 cm) and when the listener is at a position 5 cm shifted laterally from the origin position (x=5 cm).

[0093] FIG. 8B shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=60°) and two separate speakers are placed on the left sagittal plane (φ=-60°), as in the embodiment, and the listener is at the origin position (x=0 cm) and when the listener is at a position 5 cm shifted laterally from the origin position (x=5 cm).

[0094] Figure 8AB shows that when two speakers are placed on the right sagittal plane (φ=30° or 60°) and two separate speakers are placed on the left sagittal plane (φ=-30° or 60°), even when the listener is at the origin position (x=0 cm) or moves 5 cm horizontally, the flatness of the direct component is maintained to a certain extent, the crosstalk component is also maintained to a small extent, and control performance is maintained. Furthermore, it can be seen that the playback level of the direct component and the dynamic range are also maintained to a certain extent.

[0095] FIG. 8C shows a comparison of the frequency characteristics of the synthesized signal when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) and two separate speakers are placed on the left sagittal plane (φ=-90°, i.e., on the transverse plane), as in the embodiment, and the listener is at the origin position (x=0 cm) and when the listener is at a position 5 cm laterally shifted from the origin position (x=5 cm).

[0096] Figure 8C shows that when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) and two separate speakers are placed on the left sagittal plane (φ=-90°, i.e., on the transverse plane), even if the listener moves 5 cm horizontally, the flatness of the direct component is maintained to a certain extent, the crosstalk component is also maintained to a small extent, and control performance is maintained. Furthermore, whether the listener is at the origin position (x=0 cm) or at a position shifted 5 cm horizontally (x=5 cm), the playback level of the direct component and the dynamic range are also maintained to a certain extent.

[0097] Under the above simulation conditions, when d1(n) = δ(n), d2(n) = 0 is used as the input signal (when attempting to reproduce the right channel of the binaural signal), the average frequency values ​​of the crosstalk cancellation amount when the listener is positioned in each horizontal direction (x-axis direction) and vertical direction (y-axis direction) are shown in Figures 9ABCD and 10ABC.

[0098] 9ABCD and 10ABC, the horizontal axis indicates the distance the listener moved in the horizontal direction (x-axis direction), and the vertical axis indicates the distance the listener moved in the vertical direction (y-axis direction). The whiter the area, the greater the amount of crosstalk cancellation.

[0099] FIG. 9A is a diagram showing the average amount of crosstalk cancellation when two speakers are arranged horizontally as in the background art.

[0100] FIG. 9B is a diagram showing the average value of the amount of crosstalk cancellation when two speakers are arranged on the right sagittal plane (φ=30°) as in the background art.

[0101] FIG. 9C is a diagram showing the average amount of crosstalk cancellation when two speakers are arranged on the right sagittal plane (φ=60°) as in the background art.

[0102] FIG. 9D is a diagram showing the average amount of crosstalk cancellation when two speakers are arranged on the right sagittal plane (φ=90°, ie, on the transverse plane) as in the background art.

[0103] FIG. 10A shows the average amount of crosstalk cancellation when two speakers are placed on the right sagittal plane (φ=30°) and two separate speakers are placed on the left sagittal plane (φ=-30°), as in the embodiment.

[0104] FIG. 10B shows the average amount of crosstalk cancellation when two speakers are placed on the right sagittal plane (φ=60°) and two separate speakers are placed on the left sagittal plane (φ=-60°), as in the embodiment.

[0105] FIG. 10C shows the average amount of crosstalk cancellation when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) as in the embodiment, and two separate speakers are placed on the left sagittal plane (φ=-90°, i.e., on the transverse plane).

[0106] Comparing Figures 9A and 9BCD, it can be seen that the amount of crosstalk cancellation is maintained over a wider range in the horizontal and vertical directions when two speakers are arranged on the right sagittal plane (φ=30°, 60°, or 90°) as in the background art, than when two speakers are arranged horizontally as in the background art.

[0107] Comparing Figures 9A and 10A, B, C, and D, it can be seen that the amount of crosstalk cancellation is maintained over a wider range in both the horizontal and vertical directions when two speakers are arranged on the right sagittal plane (φ=30°, 60°, or 90°) as in the embodiment and two separate speakers are arranged on the left sagittal plane (φ=-30°, -60°, or -90°) than when two speakers are arranged horizontally as in the background art.

[0108] Under the above simulation conditions, when d1(n)=0 and d2(n)=δ(n) are used as the input signal (when attempting to reproduce the left channel of a binaural signal), the frequency average values ​​of the amount of crosstalk cancellation when the listener is positioned in each horizontal direction (x-axis direction) and vertical direction (y-axis direction) are shown in Figures 11ABCD and 12ABC.

[0109] 11ABCD and 12ABC, the horizontal axis indicates the distance the listener moved in the horizontal direction (x-axis direction), and the vertical axis indicates the distance the listener moved in the vertical direction (y-axis direction). The whiter the area, the greater the amount of crosstalk cancellation.

[0110] FIG. 11A is a diagram showing the average amount of crosstalk cancellation when two speakers are arranged horizontally as in the background art.

[0111] FIG. 11B is a diagram showing the average value of the amount of crosstalk cancellation when two speakers are arranged on the right sagittal plane (φ=30°) as in the background art.

[0112] FIG. 11C is a diagram showing the average value of the amount of crosstalk cancellation when two speakers are arranged on the right sagittal plane (φ=60°) as in the background art.

[0113] FIG. 11D is a diagram showing the average amount of crosstalk cancellation when two speakers are arranged on the right sagittal plane (φ=90°, ie, on the transverse plane) as in the background art.

[0114] FIG. 12A shows the average amount of crosstalk cancellation when two speakers are placed on the right sagittal plane (φ=30°) and two separate speakers are placed on the left sagittal plane (φ=-30°), as in the embodiment.

[0115] FIG. 12B shows the average amount of crosstalk cancellation when two speakers are placed on the right sagittal plane (φ=60°) and two separate speakers are placed on the left sagittal plane (φ=-60°), as in the embodiment.

[0116] FIG. 12C shows the average amount of crosstalk cancellation when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) as in the embodiment, and two separate speakers are placed on the left sagittal plane (φ=-90°, i.e., on the transverse plane).

[0117] Comparing Figures 11A and 11BCD, it can be seen that the area in which the amount of crosstalk cancellation is maintained is narrower when two speakers are arranged on the right sagittal plane (φ=30°, 60°, or 90°) as in the background art than when two speakers are arranged horizontally as in the background art.

[0118] Comparing Figures 11A and 12A, B and C, it can be seen that the amount of crosstalk cancellation is maintained over a wider range in the horizontal and vertical directions when two speakers are arranged on the right sagittal plane (φ=30°, 60°, or 90°) as in the embodiment and two separate speakers are arranged on the left sagittal plane (φ=-30°, 60°, or 90°) than when two speakers are arranged horizontally as in the background art.

[0119] Under the above simulation conditions, when d1(n) = δ(n), d2(n) = 0 is used as the input signal (when attempting to reproduce the right channel of the binaural signal), the flatness of the frequency characteristics of the direct component when the listener is positioned in each horizontal direction (x-axis direction) and vertical direction (y-axis direction) is shown in Figures 13ABCD and 14ABC.

[0120] 13ABCD and 14ABC, the horizontal axis represents the distance the listener moved horizontally (x-axis direction), and the vertical axis represents the distance the listener moved vertically (y-axis direction). The darker the area, the more flat the direct component.

[0121] FIG. 13A is a diagram showing the flatness of the frequency characteristics of the direct component when two speakers are arranged horizontally as in the background art.

[0122] FIG. 13B is a diagram showing the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=30°) as in the background art.

[0123] FIG. 13C is a diagram showing the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=60°) as in the background art.

[0124] FIG. 13D is a diagram showing the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=90°, ie, on the transverse plane) as in the background art.

[0125] Figure 14A shows the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=30°) and two separate speakers are placed on the left sagittal plane (φ=-30°) as in the embodiment.

[0126] Figure 14B shows the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=60°) and two separate speakers are placed on the left sagittal plane (φ=-60°) as in the embodiment.

[0127] Figure 14C shows the flatness of the frequency response of the direct component when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) as in the embodiment, and two separate speakers are placed on the left sagittal plane (φ=-90°, i.e., on the transverse plane).

[0128] Comparing Figures 13A and 13BCD, it can be seen that the area with high flatness is wider when two speakers are arranged on the right sagittal plane (φ=30°, 60°, or 90°) as in the background art than when two speakers are arranged horizontally as in the background art.

[0129] Comparing Figures 13A and 14A, B, C, it can be seen that the area with high flatness is wider when two speakers are placed on the right sagittal plane (φ=30°, 60°, or 90°) as in the embodiment and two separate speakers are placed on the left sagittal plane (φ=-30°, -60°, or -90°) than when two speakers are placed horizontally as in the background art.

[0130] Under the above simulation conditions, when d1(n)=0 and d2(n)=δ(n) are used as the input signal (when attempting to reproduce the left channel of the binaural signal), the flatness of the frequency characteristics of the direct component when the listener is positioned in each horizontal direction (x-axis direction) and vertical direction (y-axis direction) is shown in Figures 15ABCD and 16ABC.

[0131] 15ABCD and 16ABC, the horizontal axis represents the distance the listener moved horizontally (x-axis direction), and the vertical axis represents the distance the listener moved vertically (y-axis direction). The darker the area, the more flat the direct component.

[0132] FIG. 15A is a diagram showing the flatness of the frequency characteristics of the direct component when two speakers are arranged horizontally as in the background art.

[0133] FIG. 15B is a diagram showing the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=30°) as in the background art.

[0134] FIG. 15C is a diagram showing the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=60°) as in the background art.

[0135] FIG. 15D is a diagram showing the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=90°, ie, on the transverse plane) as in the background art.

[0136] Figure 16A shows the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=30°) and two separate speakers are placed on the left sagittal plane (φ=-30°) as in the embodiment.

[0137] Figure 16B shows the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=60°) and two separate speakers are placed on the left sagittal plane (φ=-60°) as in the embodiment.

[0138] Figure 16C shows the flatness of the frequency characteristics of the direct component when two speakers are placed on the right sagittal plane (φ=90°, i.e., on the transverse plane) as in the embodiment, and two separate speakers are placed on the left sagittal plane (φ=-90°, i.e., on the transverse plane).

[0139] Comparing Figures 15A and 15BCD, it can be seen that the area with high flatness is narrower when two speakers are arranged on the right sagittal plane (φ=30°, 60°, or 90°) as in the background art than when two speakers are arranged horizontally as in the background art.

[0140] Comparing Figures 15A and 16A, B and C, it can be seen that the area with high flatness is wider when two speakers are arranged on the right sagittal plane (φ=30°, 60°, or 90°) as in the embodiment and two separate speakers are arranged on the left sagittal plane (φ=-30°, -60°, or -90°) than when two speakers are arranged horizontally as in the background art.

[0141] [Variations] The above describes the embodiments of the present invention, but the specific configuration is not limited to these embodiments, and it goes without saying that even if design changes are made as appropriate within the scope of the present invention, they are still included in the present invention.

[0142] The various processes described in the embodiments may not only be executed in chronological order according to the order described, but may also be executed in parallel or individually depending on the processing capabilities of the devices executing the processes or as necessary.

[0143] For example, data may be exchanged directly between the components of the stereophonic sound reproduction device, or may be exchanged via a storage unit (not shown).

[0144] [Programs, recording media] The processing of each unit of the above-described stereophonic reproduction device may be realized by a computer, in which case the processing contents of the functions that the stereophonic reproduction device should have are described by a program. This program is then loaded into storage unit 1020 of computer 1000 shown in Fig. 17 and operated by arithmetic processing unit 1010, input unit 1030, output unit 1040, etc., thereby realizing various processing functions of the stereophonic reproduction device on the computer.

[0145] The program describing the processing contents can be recorded on a computer-readable recording medium, such as a non-transitory recording medium, specifically a magnetic recording device, an optical disk, or the like.

[0146] The program may be distributed, for example, by selling, transferring, lending, etc. a portable recording medium such as a DVD or CD-ROM on which the program is recorded. Furthermore, the program may be stored in a storage device of a server computer, and then transferred from the server computer to another computer via a network, thereby distributing the program.

[0147] A computer that executes such a program, for example, first stores the program recorded on a portable recording medium or transferred from a server computer in its own non-transitory storage device, auxiliary storage unit 1050. Then, when executing a process, the computer loads the program stored in auxiliary storage unit 1050, its own non-transitory storage device, into storage unit 1020 and executes processing in accordance with the loaded program. Alternatively, as another form of execution of this program, the computer may load the program directly from a portable recording medium into storage unit 1020 and execute processing in accordance with the program. Furthermore, each time a program is transferred from a server computer to this computer, the computer may execute processing in accordance with the received program. Alternatively, the server computer may not transfer the program to this computer, but may instead execute the processing function by issuing an execution instruction and obtaining the results, thereby executing the above-described processing through a so-called ASP (Application Service Provider) type service. Note that the program in this embodiment includes information used for processing by a computer that is equivalent to a program (such as data that is not a direct instruction to a computer but has properties that define computer processing).

[0148] In this embodiment, the device is configured by executing a predetermined program on a computer, but at least a part of the processing may be realized by hardware. For example, the first signal processing unit 1, the second signal processing unit 3, the control filter vector calculation unit 5, and the control filter vector calculation unit 6 may be configured by processing circuits. Furthermore, the storage unit 1020 may be a memory.

[0149] It goes without saying that other modifications are possible without departing from the spirit of the present invention.

Claims

1. a first speaker array consisting of two or more speakers arranged on a sagittal plane to the right of a listener; a second speaker array consisting of two or more speakers arranged on the sagittal plane to the left of the listener; a first signal processing unit that performs crosstalk cancellation processing to cancel out sounds reaching the left ear of the listener from the first speaker row and generates a first processed signal; a second signal processing unit that performs crosstalk cancellation processing to cancel out sounds reaching the right ear of the listener from the second speaker row and generates a second processed signal, the first speaker row emits a sound based on the first processed signal; the second speaker row emits a sound based on the second processed signal; Three-dimensional sound reproduction device.

2. a first speaker array consisting of two or more speakers arranged to the right of the listener and in a cross section of the listener; a second speaker array consisting of two or more speakers arranged to the left of the listener and in a cross-sectional plane of the listener; a first signal processing unit that performs crosstalk cancellation processing to cancel out sounds reaching the left ear of the listener from the first speaker row and generates a first processed signal; a second signal processing unit that performs crosstalk cancellation processing to cancel out sounds reaching the right ear of the listener from the second speaker row and generates a second processed signal, the first speaker row emits a sound based on the first processed signal; the second speaker row emits a sound based on the second processed signal; Three-dimensional sound reproduction device.

Images