JP5655378B2 - Sound image control device and program - Google Patents

Description

  The present invention relates to a sound image localization technique, and more particularly to a technique for controlling the apparent size of a sound image.

  Humans depend on the time difference between the sound coming from the sound source to the left and right ears (phase difference corresponding to the difference in the sound propagation path) and the difference in the sound magnitude coming from the left and right ears (difference in the sound propagation path difference). The direction of the sound source is perceived by the difference in amplitude attenuation), and a virtual image (sound image) corresponding to the sound source is perceived. Sound image localization technology uses this, and by adjusting the time difference between the amplitude and phase of sound radiated from each of a plurality of speakers through electrical signal processing, the sound image localization technology is positioned at a predetermined position as viewed from the listener. This is a technology that localizes the sound image. For example, in a stereo audio system including one speaker on each of the left and right, by making the amplitude of the audio signal applied to each speaker equal, the sound image corresponding to the audio signal can be localized in the middle of these speakers. it can.

JP 2002-345095 A JP-A-10-322799 JP-A-8-154300

By the way, it is generally known that a sound image is perceived as having a spatial extent corresponding to a sound source (hereinafter, such spatial extent is referred to as “apparent size of a sound image”). For example, the apparent size of the sound image perceived by the person who is interacting (that is, the sound image corresponding to the speaking voice of the other party) is approximately equal to the size of the head of the other party. For this reason, it is preferable that the apparent size of the sound image localized by the sound image localization technique can be quantitatively controlled according to the sound source or the like. Conventionally, a technique for controlling the sense of spread of a sound field by lowering the correlation between audio signals applied to left and right channel speakers (for example, adjusting the phase of both audio signals so that both signals are in reverse phase) (for example, However, there is no technique for quantitatively controlling the apparent size of the sound image. However, it is not impossible to widen or shrink the apparent size of the sound image by the technique disclosed in Patent Document 1 or the like, but the sound image is hazy and unclear and lacks clarity. In addition, there is a problem that the sound field may become unnatural due to the phase adjustment. In the first place, the sense of expanse of the sound field is an audible impression given by the incoming sound that surrounds the listener (for example, the feeling of being wrapped in a sound as if listening to an orchestra performance in a large concert hall). This is an auditory impression different from the apparent size of the sound image.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique that makes it possible to quantitatively control the apparent size while keeping a sound image clear.

  In order to solve the above-described problems, the present invention provides a plurality of sound images in which a position and an apparent size of a certain sound image are set, and are localized in an area defined by the set position and size. Based on the set position and the apparent size, sound image information indicating the position of each of the plurality of sound images that causes the listener to perceive a single sound image that is localized at the position and has the apparent size is synthesized. Sound image information generating means for generating the output audio signal to be provided to each of the plurality of speakers by adjusting the amplitude of the input audio signal, wherein the position of each of the plurality of speakers and the sound image are generated. A speaker group contributing to the localization of each of the plurality of sound images is specified from the position of each sound image indicated by the information, and the sound image information is indicated by the sound radiated from each speaker group. Each of the plurality of sound image in a position to provide a sound image control apparatus, characterized in that it comprises a signal generating means for generating the respective output audio signal to be localized. According to another aspect of the present invention, there is provided a program that causes a computer to function as each of the above means.

  According to such a sound image control device, drive control of each of the plurality of speakers is performed so that the plurality of sound images are localized in the region where the position and size are set by the user. If the size of the area and the distribution of a plurality of sound images localized in the area are appropriately determined, the listener perceives one sound image synthesized from the plurality of sound images (the plurality of sound images). Are perceived as a single sound image having a spread according to the distribution of the multiple sound images). It should be noted that in the present invention, the localization of each of the plurality of sound images is realized by adjusting the amplitude of the audio signal applied to each speaker, and filtering processing and addition / subtraction of the plurality of signals are not performed. Is a point. Since the filtering process and addition / subtraction of multiple signals are not performed, the sound field is unlikely to be unnatural and one sound image perceived by the listener (the sound image synthesized by superimposing the multiple sound images) is cleared. You can keep it. In addition, according to the present invention, the position of the sound image and its apparent size are quantitatively set with numerical values, and the amplitude of the output audio signal is adjusted so that a plurality of sound images are localized according to the setting contents. Therefore, the apparent size of the sound image can be controlled quantitatively.

It is a figure which shows the structural example of the sound image control apparatus 1 which is one Embodiment of this invention. Is a diagram showing the positional relationship between the arrangement and the listener of the speaker SP _{n (n} = 1~8) which is an audio signal supplied from the sound image control apparatus 1. It is a figure which shows an example of the sound image localization by the sound image control apparatus.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration example of a sound image control apparatus 1 according to an embodiment of the present invention.
The sound image control apparatus 1 receives a monaural audio signal IN in a digital format and generates an 8-channel digital audio signal (in FIG. 1, an output audio signal Z _n (n = 1 to 8)) from the monaural audio signal IN. It is a device that outputs. Each of the output audio signals Z _n (n = 1 to 8) is converted into an analog audio signal by a D / A converter (not shown in FIG. 1), passes through a power amplifier or the like (also not shown), and then enters the acoustic space. Is provided to each of the speakers SP _n (n = 1 to 8).

FIG. 2 is a diagram illustrating an arrangement example of eight speakers driven by the sound image control apparatus 1.
As shown in FIG. 2, each of the speakers SP _n (n = 1 to 8) is arranged with its speaker axis directed toward the center of gravity of the regular octagon so as to draw a regular octagon with each apex. When the position of the listener the center of gravity of the regular octagon (listening point), by appropriately adjusting the amplitude of the audio signal to be supplied to the speaker SP _n and the speaker SP n _{+ 1,} any position between the speaker SP _n and the speaker SP n _{+ 1} The sound image can be localized. For example, in order to localize a sound image to right in the middle of the speaker SP _n and the speaker SP n _{+ 1,} the amplitude of the audio signal to be supplied to each of the speakers SP _n and the speaker SP n _{+ 1} may be such that the same.

In the present embodiment, the speaker SP _n (n = 1 to 8) is arranged so that the position of the sound image to be localized and the apparent size can be quantitatively set according to the audio signal IN. Assume two-dimensional coordinates on a plane. More specifically, the center of gravity of the regular octagon (in this embodiment, the listening point) is defined as a coordinate origin O (0, 0), and the direction from the coordinate origin O toward the speaker SP ₁ is set to one coordinate axis (in FIG. 2). , Y axis), and a two-dimensional orthogonal coordinate (XY coordinate) in which the direction from the coordinate origin O toward the speaker SP ₃ is the + direction of the other coordinate axis (X axis in this embodiment) is assumed. Assuming such two-dimensional orthogonal coordinates, as shown in FIG. 2, the positions of the speakers SP _{1 to} SP ₈ are (0, 100), (71, 71), (100, 0), ( 71, −71), (0, −100), (−71, −71), (−100, 0), and (−71, 71). In the present embodiment, speaker information representing the position coordinates of each speaker SP _n (n = 1 to 8) is stored in advance in storage means (eg, hard disk or flash memory, not shown in FIG. 1) of the sound image control device 1. Stored.

  In the present embodiment, the position of the sound image to be localized according to the audio signal IN is set to the user at an angle θ representing the direction viewed from the listening point (clockwise angle with the + direction of the Y axis being the 0 degree direction). Further, the user is allowed to set the apparent size of the same sound image (in this embodiment, the angle φ over which the same sound image is seen from the listening point). In this embodiment, the intersection of a straight line drawn from the coordinate origin O in the direction of the angle θ and the side of the regular octagon is set as the position of the sound image, the main sound image M is localized at this position, and the interval according to the angle φ The process of localizing the two sub-sound images S1 and S2 facing each other at an equal distance across the main sound image M by adjusting the amplitude instead of adjusting the phase (delay time) as described later. This is executed by the sound image control apparatus 1. As described above, in the present embodiment, a plurality of sound images (in this embodiment, the main sound image M and the sub sound images S1 and S2) are evenly localized in the region defined by the angles θ and φ set by the user. As a result, the listener at the position of the coordinate origin O is perceived as one sound image obtained by synthesizing the main sound image M and the sub sound images S1 and S2 (the main sound image M and the sub sound images S1 and S2 slightly overlap each other). A perceived sound image having a spread corresponding to the distribution of the main sound image M and the sub sound images S1 and S2 is perceived. That is, according to the sound image control apparatus 1 of the present embodiment, the listener can perceive one sound image that is localized at a position set by the user and has an apparent size set by the user. It can be done. Hereinafter, the configuration and function of the sound image control apparatus 1 that clearly show the features of the present embodiment will be described in detail.

  The sound image control device 1 is, for example, a DSP (Digital Signal Processor), and executes sound image control processing that significantly shows the features of the present embodiment in accordance with a signal processing program installed in advance. More specifically, the sound image control apparatus 1 executes the signal processing program, thereby performing sound image information generation means 10, amplifiers 20M, 20S1 and 20S2, sound image localization gain adjustment means 30M, 30S1 and 30S2, and adder 40. It functions as -n (n = 1-8). As described above, in the present embodiment, each component of the sound image control device 1 is realized by software. However, the sound image control device 1 may be configured by combining hardware such as an electronic circuit and combining these electronic circuits. good.

The sound image information generating means 10 in FIG. 1 is a sound image intended to be localized by sound emitted from the speaker SP _n (n = 1 to 8) (a sound image obtained by synthesizing the main sound image M and the sub sound images S1 and S2). (In this embodiment, as described above, the angle θ representing the direction of the sound image viewed from the coordinate origin O, which is the listening point) and the angle φ representing the apparent size of the sound image are set by the user. Then, sound image information DM, DS1, and DS2 indicating positions where the main sound image M and the sub sound images S1 and S2 are localized are generated according to the set contents. Here, the sound image information DM is data indicating the Y coordinate M_y at the same position as the X coordinate M_x of the position of the main sound image M, and the sound image information DS1 is the Y coordinate of the same position as the X coordinate S1_x of the sub sound image S1. The sound image information DS2 is data indicating the Y coordinate S2_y at the same position as the X coordinate S2_x of the position of the sub sound image S2. More specifically, the sound image information generating means 10 displays a GUI screen for setting an angle θ indicating the direction of the sound image viewed from the listening point and an angle φ indicating the apparent size of the sound image, such as a liquid crystal display. It is displayed on a device (not shown in FIG. 1). When (θ, φ) is input by numerical input using a keyboard or the like, or by drag and drop using a pointing device such as a mouse, the sound image information generating means 10 performs sound image information DM, DS1, and DS2 as follows. Is generated.

First, the sound image information generating means 10 obtains an intersection between a regular octagonal side having each of the speakers SP _n (n = 1 to 8) as vertices and a straight line drawn from the coordinate origin O in the direction of the angle θ, and the intersection point. X coordinate M_x and Y coordinate M_y of the intersection. For example, when θ = 20 degrees is set, the sound image information DM is calculated as (32, 93). Next, the sound image information generating means 10 obtains the intersection point between the side of the regular octagon and the straight line drawn in the direction of the angle (θ−φ / 2) from the coordinate origin O, the X coordinate S1_x of the intersection point, and the Y of the intersection point Similarly, the coordinate S1_y is obtained, and similarly, the intersection of the regular octagonal side and the straight line drawn in the direction of the angle (θ + φ / 2) from the coordinate origin O is obtained, and the X coordinate S2_x of the intersection and the Y coordinate S2_y of the intersection are obtained. To get. For example, when θ = 20 degrees and φ = 50 degrees are set, the direction of the secondary sound image S1 viewed from the listening point is 20−25 = −5 degrees (ie, 355 degrees), The direction of the secondary sound image S2 is set to 20 + 25 = 45 degrees. In the present embodiment, the position of the sound image viewed from the listening point is set by the angle θ. However, it is of course possible to set the coordinate value and calculate the angle θ from the setting contents. The position of the sound image may be specified by the direction θ of the viewed sound image and the distance r to the sound image. Thus, in the aspect in which the position of the sound image is set by (r, θ), the positions of the main sound image M, the sub sound image S1, and the sub sound image S2 may be calculated by the following equation (1).

Amplifier 20M of FIG. 1, 20S1,20S2, sound image localization for the gain adjustment unit 30M, 30S1,30S2, and adder 40-1～40-8 the signal generating means for generating an output audio signal Z _n from the input audio signal IN Function as. The audio signal IN input to the sound image control device 1 is distributed according to the number of sound images to be localized in the area defined by the angles (θ, φ) set by the user (three in this embodiment). Then, as shown in FIG. 1, it is supplied to each of the amplifier 20M, the amplifier 20S1, and the amplifier 20S2. The amplifier 20M adjusts the amplitude of the audio signal IN to adjust the audio signal XM, the amplifier 20S1 adjusts the amplitude of the audio signal IN to adjust the audio signal XS1, and the amplifier 20S2 adjusts the amplitude of the audio signal IN to adjust the audio signal. XS2 is generated. Although details will be described later, the audio signal XM is used to generate an audio signal YM _n (n = 1 to 8) for realizing the localization of the main sound image M, and the audio signal XS1 realizes the localization of the sub sound image S1. Audio signal YS1 _n (n = 1 to 8) is generated, and audio signal XS2 is used to generate audio signal YS2 _n (n = 1 to 8) for localization of sub sound image S2. . The ratio of the amplitudes of the audio signals XM, XS1, and XS2 is related to the loudness (sound pressure) corresponding to each of the main sound image M and the sub sound images S1 and S2. In the present embodiment, the amplitude adjustment amount (amplification factor) g _m in the amplifier 20M and the amplitude adjustment amounts g _s in the amplifiers 20S1 and 20S2 are as follows using the parameter x in the range of 0.5 to 1.0. The square root of each sum of squares is a constant value (1 in this embodiment) as shown in Expression 3.

As can be seen from Equation 2, when x = 1.0, g _m = 1 and g _s = 0, and as parameter x becomes smaller than 1, g _m decreases and g _s increases. When x = 0.5, g _m = g _s (= the reciprocal of the square root of 3). Therefore, when only the main sound image M is localized and the sub sound images S1 and S2 are not localized, it is only necessary to set x = 1.0. As shown in FIG. In order to make the size of the sound image uniform, x = 0.5 may be set. That is, the parameter x is an amount that represents the ratio of the size of the main sound image M and the sub sound images S1 and S2. The sub sound images S1 and S2 are the same size sound image, and the main sound image M and the sub sound images S1 and S2 Of the total three sound images, the amount corresponding to the sum of the amounts corresponding to the acoustic energy of each sound image is normalized to 1. In the present embodiment, a value smaller than 1 and larger than 0.5 (for example, 0.7) is preset as the parameter x. Therefore, in the present embodiment, g _m> g _s, and the (higher sound pressure) superior in comparison to the sub-sound S1 and the sub-sound image S2 as shown in FIG. 3 (A) main sound M the sound image information DM The signal processing is performed so as to localize the position indicated by. In the present embodiment, the value of the parameter x is set in advance in the range of 0.5 to 1.0. However, the sound image information generating unit 10 may set the value each time.

Sound image localization for gain adjustment means 30M in FIG. 1, an audio signal XM (in this embodiment, 8) the number of speakers SP _n distributed according to, further, by adjusting the amplitude of each audio signal distributed audio A signal YM _n (n = 1 to 8) is generated. Similarly, the sound image localization gain adjusting unit 30S1 generates and outputs an audio signal YS1 _n (n = 1 to 8) from the audio signal XS1, and the sound image localization gain adjusting unit 30S2 receives the audio signal YS2 from the audio signal XS2. _n (n = 1 to 8) is generated and output. The audio signal YM _n (n = 1 to 8) generated by the sound image localization gain adjusting means 30M gives only the audio signal YM _n (n = 1 to 8) to each of the speakers SP _n to emit sound. In this case, only the main sound image M is localized at the position of the main sound image M indicated by the sound image information DM. Similarly, when the audio signal YS1 _n (n = 1 to 8) is radiated by giving only the audio signal YS1 _n (n = 1 to 8) to each of the speakers SP _n , only the sub sound image S1 is obtained. Is an audio signal that is localized at the position of the sub sound image S1 indicated by the sound image information DS1. Further, the audio signal YS2 _n (n = 1 to 8) is obtained by applying only the audio signal YS2 _n (n = 1 to 8) to each of the speakers SP _n to emit sound, and only the sub sound image S2 is obtained. This audio signal is localized at the position of the sub sound image S2 indicated by the sound image information DS2. Since each of the sound image localization gain adjustment means 30M, 30S1 and 30S2 executes the same processing to generate each audio signal, only the sound image localization gain adjustment means 30M will be described in detail below.

First, the sound image localization gain adjusting means 30M uses the following as a number k (k is any one of 1 to 8) indicating a speaker group (hereinafter referred to as a speaker pair) composed of two speakers responsible for localization of the main sound image M. Those satisfying the condition shown in Equation 4 are specified. Here, the speaker pair corresponding to the speaker pair number k is the speakers SP _k and SP _{k + 1} . For example, when k = 1, the corresponding speakers are speakers SP ₁ and SP ₂ , and when k = 8, the corresponding speakers are speakers SP ₈ and SP _{8 + 1} (= SP ₁ ). In Equation 4, SP _{k —} x is the X coordinate of the placement position of the speaker SP _k , and SP _{k —} y is the Y coordinate of the placement location (however, in the following Equation 4, when k = 8, SP _{k + 1} _X = SP ₁ _x and SP _{k + 1} _y = SP ₁ _y). In Equation 4, min (a, b) means the smaller of the two numbers a and b (that is, if a <b, min (a, b) = a), max (a , B) means the larger of the two numbers a and b (ie, if a <b, max (a, b) = b). As can be seen from Equation 4, the sound image localization gain adjusting means 30M is a speaker pair composed of two speakers arranged next to each other on a line segment connecting the two speakers (more generally). In this case, a speaker in which the main sound image M is located within a rectangle having the line segment as a diagonal line) is specified as a speaker pair in charge of localization of the main sound image M.

When the number k indicating the speaker pair in charge of localization of the main sound image M is determined as described above, the sound image localization gain adjusting unit 30M converts the audio signal XM to the audio signal YM _n (n = 1 to 8, where n ≠ k and n ≠ k + 1) gain when generating (amplification factor) of _{G n} is zero, and a gain _{G k + 1} when generating a gain _{G k} and the audio signal _{YM k + 1} at the time of generating the audio signal YM _k The values shown in the following Expression 5 are used (however, as in Expression 4, when k = 8, YM _{k + 1} = YM ₁ and G _{k + 1} = G ₁ ). As it is clear by referring to the number 5, and the gain G _k in generating the audio signal YM _k, 2 sum of squares of each gain G _{k + 1} at the time of generating the audio signal YM k _{+ 1} becomes 1. The value a calculated according to Equation 5 is the magnitude of the vector product (outer product) of the position vector of the main sound image M starting from the coordinate origin O and the position vector of the speaker SP _k (both vectors are two sides). The position of the speaker SP _{k + 1} starting from the listening point O and the position of the speaker SP _k are obtained by multiplying the area of the parallelogram, that is, the magnitude of each vector by the sine value of the angle formed by both vectors. It is a value obtained by dividing by the magnitude of the vector product of the vectors. Similarly, the value b calculated according to Equation 5 is the loudspeaker starting from the listening point O and the magnitude of the vector product of the position vector of the main sound image M starting from the coordinate origin O and the position vector of the speaker SP _{k + 1.} This value is obtained by dividing by the magnitude of the vector product of the position vector of SP _{k + 1 and} the position vector of speaker SP _k . Here, when attention is paid to the geometrical meaning of the vector product, Equation 5 indicates that “the sum of squares of the gain of the audio signal applied to each of the two speakers in charge of localization of the main sound image M is a constant value (for example, 1 In addition, the length of a perpendicular line in which the gain of the audio signal applied to each speaker is lowered from the position of the main sound image M to the straight line passing through the position of the other speaker and the coordinate origin O is calculated from the position of the speaker. This means that the gain of the audio signal to be given to both speakers is determined so as to be proportional to the value divided by the length of the vertical line drawn down.

When the positions of the main sound image M and the sub sound images S1 and S2 are calculated as shown in FIG. 3A (for example, when θ = 20 degrees and φ = 50 degrees are set), the main sound image M is the speaker SP _1. And SP ₂ , the sound image localization gain adjusting means 30M specifies k = 1 as the number k indicating the speaker pair responsible for the localization of the main sound image M. For this reason, the sound image localization gain adjusting means 30M calculates the gains G ₁ and G ₂ in accordance with Equation 5 (specifically, G ₁ = 0.9576 and G ₂ = 0.2880). , G _n (n = 3 to 8) is set to zero, and audio signals YM _n (n = 1 to 8) are generated and output with amplification factors corresponding to these gains. Similarly, because the sub-sound S1 is it to position between the speaker SP ₈ and SP ₁ (see FIG. 3 (A)), the sound image localization for the gain adjustment unit 30S1 is a speaker pair responsible for localization of the secondary sound image S1 The indicated number k is specified as k = 8, gains G ₈ and G ₉ (G ₁ as described above) are calculated according to Equation 5, G _n (n = 2 to 7) is set to zero, and each of these gains is calculated. The audio signal YS1 _n (n = 1 to 8) is generated and output at an amplification factor according to. Similarly, with the sound image localization for the gain adjustment unit 30S2 is, the number k indicating the speaker pair responsible for localization of the secondary sound S2 identified as k = 2, calculates the gain G ₂ and G ₃ according to Equation 5, G _n (n = 1, 4 to 8) is set to zero, and an audio signal YS2 _n (n = 1 to 8) is generated and output at an amplification factor corresponding to each gain.

Adder Figure 1 40-n (n = 1~8 ) is an audio signal _YM n, YS1 _n and YS2 _n sum signal _{Z n (i.e., Z n = YM n + YS1} n + YS2 n) generating and outputting To do. As described above, the main sound image M, the value each position of the sub-sound S1 and S2 are in a situation where determined as shown in FIG. 3 (A), the amplitude of the audio signal YM ₁ and YM ₂ is calculated according to Equation 5 (That is, a value that contributes to localization of the main sound image M), and the amplitude of the audio signal YM _n (n = 3 to 8) is zero. Similarly, the amplitudes of the audio signals YS1 ₈ and YS1 ₁ are values calculated according to Equation 5 (that is, values that contribute to the localization of the sub sound image S1), and the audio signals YS1 _n (n = 2 to 7). Has an amplitude of zero. Then, the audio signals YS2 ₂ and YS2 ₃ value amplitude which is calculated according to Equation 5 (i.e., contributing value to localization of the secondary sound S2) has a audio signal _YS2 n (n = _1,4~8 ) Is 0. Therefore, the audio signals Z ₁ , Z ₂ , Z ₃ and Z ₈ output from each of the adders 40-n (n = 1 to 8) each include the following signal components, and the other (Z _n : n = 4 to 7) is 0.
Z ₁ = signal component contributing to the localization of the main sound image M + signal component contributing to the localization of the sub sound image S 1 Z ₂ = signal component contributing to the localization of the main sound image M + signal component contributing to the localization of the sub sound image S ₂ Z ₃ = Signal component contributing to localization of sub sound image S2 Z ₈ = Signal component contributing to localization of sub sound image S1

In this way, each of the audio signals Z _n (n = 1 to 8) output from the sound image control device 1 is D / A converted by a D / A converter (not shown) and a power amplifier (also not shown). Is supplied to the speaker SP _n of FIG. Each of the speakers _SP n of FIG. 2 (n = 1~8) is for emitting sound corresponding to the output audio signal _{Z n.} As described above, the output audio signal Z ₁ contributes to the localization of the main sound image M and the sub sound image S 1, and the output audio signal Z ₂ contributes to the localization of the main sound image M and the sub sound image S _2. signal components is, the output audio signal Z ₃ contribute signal components to localization of the secondary sound image S2 is, the output audio signal Z ₈ includes a contributing signal components localized sub sound image S1, the other output The audio signal Z _n (n = 4 to 7) is zero. Therefore, the localization of the main sound image M by the sound emitted from each of the speakers SP ₁ and the speaker SP ₂ is the localization of the sub-sound image S1 by the sound emitted from each of the speakers SP ₈ and the speaker SP ₁ is the speaker SP ₂ and localization of the secondary sound image S2 by sound radiated from each of the speakers SP ₃ is realized each sound image localization with 3 the apparent size, as indicated by a chain line in (a) by the synthesis of these three sound Is realized.

As described above, according to the sound image control apparatus 1 of the present embodiment, the main sound image M and the sub sound images S1 and S2 are localized in the region defined by the position set by the user and the apparent size. The drive control of the speaker SP _n (n = 1 to 8) is performed, and sound image localization with an apparent size is realized by combining these three sound images. The localization of these three sound images is realized by adjusting the amplitude of the audio signal applied to each of the speakers SP _n (n = 1 to 8), and since the phase is not adjusted, the sound field is kept clear. As in the technique disclosed in Patent Document 1 and the like, it is not difficult to specify the position of the sound image, and the sound field is not likely to be unnatural. In the present embodiment, the position where the sound image is localized can be set quantitatively by the direction θ viewed from the listening point, and the apparent size of the sound image can be set quantitatively by the angle φ. Is possible. Thus, according to the present embodiment, it is possible to quantitatively control the apparent size while keeping the sound image clear.

Although the embodiment of the present invention has been described above, it is needless to say that the following modifications may be added to this embodiment.
(1) In the embodiment described above, the main sound image M as shown in FIG. 3A is dominant by setting the value of the parameter x in advance, or the main sound image as shown in FIG. Each of the main sound image M, the sub sound image S1, and the sub sound image S2 is localized in any state where M and the sub sound images S1 and S2 are equal. However, by changing the parameter x from 1 to 0.5 over time, “the state where only the main sound image M is localized” → “the state where the main sound image M is dominant” → “the main sound image M and the sub sound image S1” Further, the state may be changed with time, such as “the state where S2 and S2 are equal”. Further, by changing the angle φ over time, the interval between the sub-tone images S1 and S2 and the main sound image M may be changed over time, and the apparent size of the sound image may be changed over time. Specifically, time-series data representing the angle φ at each time may be given to the sound image control apparatus 1, and the positions of the sub sound images S1 and S2 may be calculated for each time using the angle φ at that time. Similarly, it is also possible to control the position θ of the main sound image M and the sub sound images S1 and S2 to change from time to time by changing the angle θ over time. Since the localization position of the sound image obtained by synthesizing the main sound image M and the sub sound images S1 and S2 is not limited to the center of each speaker pair, the movement control of each of the main sound image M and the sub sound images S1 and S2 If the control of the apparent size of the sound image obtained by synthesizing these three sound images (control of the size of each of the main sound image M and the sub sound images S1 and S2, etc.) is used in combination, a variety of effects can be obtained by their synergistic effects. It is considered that an acoustic effect can be realized.

(2) In the embodiment described above, drive control of _eight speakers (SP _{1 to} SP ₈ ) is performed by the sound image control device 1, but drive control of two to seven speakers or nine or more speakers is performed. Needless to say you get. When two speakers are subject to drive control, it is not necessary to perform the calculation (calculation for specifying the speaker that contributes to localization of each sound image) shown in Equation 4 above, and the two speakers described above. It is only necessary to calculate the amplification factor of the audio signal to be given to each of them according to the equation 5 for each sound image, add the audio signals for each channel, and output them. Further, in the above embodiment, although the speaker SP _{n (n} = 1~8) to be driven and controlled by the sound image control apparatus 1 is arranged at the vertices of regular octagon, for example, an ellipse or parabola, any such hyperbolic You may arrange | position so that each speaker axis | shaft may face a predetermined direction along a quadratic curve (for example, it may face the focus of the said quadratic curve). A plurality of speakers may be arranged along an arbitrary curve so that each speaker faces a predetermined direction, and each speaker axis is parallel along the straight line (that is, each speaker is at infinity). Each speaker may be arranged (as if it is pointed at one point). Furthermore, a mode in which a plurality of speakers that are driven and controlled by the sound image control device 1 is arranged in a three-dimensional manner is also conceivable. Thus, in a mode in which a plurality of speakers are arranged three-dimensionally, a speaker group composed of three speakers that draw the smallest triangle and whose main sound image placement position belongs within a triangle drawn with each speaker as a vertex. What is necessary is just to specify as what contributes to the localization of a sound image (corresponding to the speaker pair in the above-described embodiment).

(3) In the above-described embodiment, one main sound image and two sub sound images are evenly localized in the area defined by the position and size set by the user. The sub sound image of m is an integer of 2 or more may be localized equally. That is, an odd number of sound images are evenly localized by combining the main sound image and each sub sound image within an area defined by the position and size set by the user. Further, an even number of sound images such as two or four may be localized in the same area. The point is that any sound image localization with an apparent size may be realized by localizing a plurality of sound images within an area defined by the position and size set by the user.

  For example, in a mode in which one main sound image and four sub sound images are localized in an area defined by the position and size set by the user, the position of the sound image is set at an angle θ, and the appearance of the sound image is Is set at an angle φ, the main sound image is localized in the direction of the angle θ, and the angles (θ−φ / 2), (θ−φ / 4), (θ + φ / 4) and (θ + φ) / 2) The sub-sound image may be localized one by one in each direction. That is, in an aspect in which one main sound image and 2m (m is an integer of 1 or more) sub sound images are localized equally in an area defined by the position and size set by the user, the angle (θ ± k × φ / 2m: However, the sub-sound images may be localized one by one in the direction of 1 ≦ k ≦ m). Similarly, in an embodiment in which an even number (2m: (m is an integer of 1 or more)) of sound images is localized in the region, an angle (θ ± k × φ / 2m: where 1 ≦ k ≦ m) The sound image may be localized one by one in each direction.

(4) In the embodiment described above, the two sub sound images facing each other across the main sound image are localized so that the distance between the main sound image M is equal, but the distance between each sub sound image and the main sound image is equal. Each sub sound image may be localized so that it does not occur. For example, when the direction of the sound image viewed from the listening point is set to the direction of the angle θ and the size of the sound image is set to the angle φ, the main sound image M is localized in the direction of the angle θ, and the sub sound image S1 is The secondary sound image S2 is localized in the angle (θ-2φ / 3) direction and the angle (θ + φ / 3) direction.

(5) In the above-described embodiment, a computer such as a DSP is used to input audio so as to localize each of the plurality of sound images at the position indicated by the sound image information generating means 10 and the sound image information generated by the sound image information generating means 10. signal signal generating means for generating an output audio signal Z _n from the iN (in Fig. 1 amplifier 20M, 20S1,20S2, sound image localization for the gain adjustment unit 30M, 30S1,30S2, and the adder 40-1～40-8) as a function The signal processing program to be executed was previously installed in the sound image control apparatus 1. However, the signal processing program may be written and distributed on a computer-readable recording medium such as a CD-ROM (Compact Disk-Read Only Memory), or the signal processing may be performed by downloading via a telecommunication line such as the Internet. You may distribute the program.

(6) In the above-described embodiment, the input audio signal IN is distributed to each of the audio signals obtained by distributing the input audio signal IN according to the number of sound images to be localized in the region defined by the position and size set by the user. On the other hand, after the first amplitude adjustment (in the above embodiment, amplitude adjustment by the amplifiers 20M, 20S1, and 20S2) for making the size of each sound image uniform (or non-uniform), each of the sound images is further provided. While generating the second amplitude adjustment output audio signal Z _n by performing (sound image localization for the gain adjustment unit 30M, 30S1, and the amplitude adjustment by 30S2) for localizing the position indicated by the sound information, the first and second Of course, the execution order of the amplitude adjustment of 2 may be changed.

(7) In the above-described embodiment, the gain of the audio signal to be given to each of the two speakers responsible for the localization of the main sound image M and the sub sound images S1 and S2 is determined by panning shown in Formula 5. However, the method of determining the gain of the audio signal to be given to each speaker is not limited to the panning, and the localization of each of the main sound image M and the sub sound images S1 and S2 is assigned to three or more speakers. May be. For example, in the case where three speakers SP ₈ , SP ₁ and SP ₂ in FIG. 2 are responsible for localization of the main sound image M, by appropriately adjusting the gain of the audio signal applied to these three speakers, from the listening point localization in the depth direction so on localizing the main sound image M at an arbitrary position on the line leading to the speaker SP ₁ also becomes possible. Further, according to such an aspect, the main sound image M and the sub sound images S1 and S2 can be localized so that the distance of the main sound image M viewed from the listening point and the distances of the sub sound images S1 and S2 are not the same. It is considered that sound image localization with a size in the depth direction can be realized.

1 ... sound image control _{apparatus, SP n (n = 1~8)} ... speaker, 10 ... acoustic image information generating means, 20M, 20S1,20S2 ... amplifier, 30M, 30S1,30S2 ... sound image localization for the gain adjustment unit, 40-n ( n = 1-8)... Adder.

Claims (6)

Is set the position and the apparent magnitude of the input audio signal controlled object sound corresponding to the user, the localization of each of the plurality of sound image is localized in the area defined by the position and size set by the user Means for generating sound image information indicating a position based on a position and size set by the user, wherein the sound image information is generated so that the control target sound image is perceived by a listener by combining the plurality of sound images; Sound image information generating means for generating;
A means for adjusting an amplitude of the input audio signal to generate an output audio signal to be provided to each of the plurality of speakers, wherein each of the plurality of sound images indicated by the arrangement position of each of the plurality of speakers and the sound image information ; A speaker group that contributes to localization of each of the plurality of sound images is identified from the localization position, and each of the plurality of sound images is localized at each localization position indicated by the sound image information by sound radiated from each speaker group. Signal generating means for generating each output audio signal;
A sound image control apparatus comprising: The signal generating means includes
The sound image control apparatus according to claim 1, wherein the amplitude of each output audio signal is adjusted so that intervals or sizes of the plurality of sound images are equal or unequal. The control target when the position of the control target sound image is set at an angle representing the direction of the control target sound image viewed from the listener's position and the size of the control target sound image is viewed from the listener The sound image control device according to claim 1, wherein the sound image control device is set at an angle overlooking the sound image. The speaker group contributes to localization in a rectangular area having a line segment connecting two speakers included in the speaker group contributing to localization of any of the plurality of sound images as a diagonal line or in a triangular area having the line segment as a side. The sound image control apparatus according to claim 1, wherein a speaker group that contributes to localization of each of the plurality of sound images is specified such that a sound image to be performed is located. The signal generation means includes only a signal component corresponding to a sound image that contributes to localization by a speaker to which the audio signal is output, among signal components corresponding to each of the plurality of sound images in an audio signal applied to each of the plurality of speakers. 5. The sound image control apparatus according to claim 1, wherein an audio signal to be provided to each of the plurality of speakers is generated.   Computer
  Localization of each of the plurality of sound images that allows the user to set the position and apparent size of the sound image to be controlled according to the input audio signal, and to localize within the region defined by the position and size set by the user Means for generating sound image information indicating a position based on a position and size set by the user, wherein the sound image information is generated so that the control target sound image is perceived by a listener by combining the plurality of sound images; Sound image information generating means for generating;
  A means for adjusting an amplitude of the input audio signal to generate an output audio signal to be provided to each of the plurality of speakers, wherein each of the plurality of sound images indicated by the arrangement position of each of the plurality of speakers and the sound image information; A speaker group that contributes to localization of each of the plurality of sound images is identified from the localization position, and each of the plurality of sound images is localized at each localization position indicated by the sound image information by sound radiated from each speaker group. Signal generating means for generating each output audio signal
  A program characterized by functioning as

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