JP3830997B2 - Depth direction sound reproducing apparatus and three-dimensional sound reproducing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a depth direction sound reproducing device that faithfully reproduces sound with depth, and a three-dimensional sound reproducing device that faithfully reproduces three-dimensional sound by providing the depth direction sound reproducing device on the left and right.
[0002]
[Summary of Invention]
The present invention uses a speaker system composed of a plurality of speakers, and adds a direct sound enhancement system in which a direct sound at a listening position is mainly enhanced and an indirect sound enhancement system in which an indirect sound is mainly enhanced. In order to drive each speaker, the input terminals of each system are driven by two independent signals, and the ratio of the direct sound and indirect sound at the listening position is changed by changing the level ratio of these two signals. This is a sound reproduction device that changes the sense of distance of a sound image, and enables the sense of distance of a sound image in the depth direction from near to far.
[0003]
[Prior art]
Conventionally, the following methods are known as methods for controlling the sense of distance of a sound image. One of them is a configuration shown in FIG. 6, which uses a two-channel stereo, adds an indirect sound to a sound source signal by reverb or the like, and changes its sense of distance by adjusting the size and characteristics. . FIG. 6 shows the structure for one channel of sound image distance control in this 2-channel stereo, but the sound source signal input to the sound source signal input terminal 101 has different delay characteristics constituting reverb. Different delays are given by a large number of delay elements 102 to 104, these are added to the original sound source signal by the adder 105, amplified by the amplifier 106, and output from the speaker 107. The left and right channel delays use different values.
[0004]
As another conventional example, a stereophonic sound reproducing apparatus using a speaker array is proposed in Japanese Patent Laid-Open No. 3-159500. This is the configuration shown in FIG. 7, in which a sound wave is focused at a position in space by a speaker array composed of a large number of speakers 111 to 113 and a large number of focus synthesis delay elements 114 to 116. A virtual sound source is synthesized by locally increasing the sound pressure of the sound, and a sound image is perceived at that location. Then, the delay amount control unit 117 changes the delay amount of each of the delay elements 114 to 116, and controls the position of the sound image including the depth direction by moving the focus position. Reference numerals 118 to 120 denote amplifiers that drive the speakers 111 to 113.
[0005]
In addition to these, a method of simulating the head-related transfer function and a method of using the localization of sound in opposite left and right phases in the head have been proposed, but none have been put into practical use.
[0006]
[Problems to be solved by the invention]
In the case of the conventional sound reproducing device shown in FIG. 6 described above, it is difficult to localize the sound image in front of the speaker 107, that is, on the listener side. The reason is that, even when no indirect sound is added to the sound source signal, the indirect sound is added by reflection of the sound wave on the wall surface of the listening room. This indirect sound can be theoretically removed by fixing the room, speaker arrangement, and listening position, and convoluting the inverse characteristics of the room response with the sound source signal, but this is not practical.
[0007]
In addition, in the case of the two-channel stereo system shown in FIG. 6, the timbre of the indirect sound added to the sound source signal itself by the reverb composed of a large number of delay elements 102 to 104 is added in the listening room. Since it is different from the timbre of the indirect sound, the timbre changes depending on the amount of the indirect sound, and there is a problem that it feels unnatural.
[0008]
Further, in the case of the conventional stereophonic sound reproducing apparatus shown in FIG. If synthesized in the vicinity of the listener, the sound image can be localized in front of the speaker array, and indirect sounds are added in the room, so that the timbre is natural.
[0009]
However, in the method using the speaker array, in order to move the focal point of the sound wave, the delay amount of the large number of delay elements 114 to 116 must be changed in real time. Therefore, an extremely large number of channels are used for recording and transmitting sound. There is a problem that requires.
[0010]
In addition, the configuration shown in FIG. 7 can control the position of only one sound image, and in order to control the sense of distance between a plurality of sound images, an independent delay amount is given to each sound source, and each focus is focused on. Therefore, the number of required delay elements increases in proportion to the number of sound images, and in addition, a special circuit that adds multi-channel signals composed of the outputs of the respective delay elements is required. There is a problem that the system becomes extremely complicated.
[0011]
The present invention has been made in view of the above-described conventional problems. A speaker array system is used, and a plurality of sound images are displayed on the near side of a speaker with a small number of channels of sound and a delay element with a constant delay amount. It is an object of the present invention to provide a depth direction sound reproducing apparatus and a three-dimensional sound reproducing apparatus that can be perceived and moved.
[0012]
[Means for Solving the Problems]
The depth direction sound reproducing device according to the first aspect of the present invention includes a plurality of speakers each including a plurality of delay elements each including two systems of a first system for direct sound and a second system for indirect sound. The delay amount of the delay element group of the system is set so that the sound wave output from each of the speakers generates a sound wave that focuses on a certain position in space as a direct sound, and the delay amount of the delay element group of the second system is The sound wave output from each speaker is set to a random value so as to generate an unfocused sound wave as an indirect sound, and a sound source signal given from the outside is distributed to two outputs of an arbitrary level ratio, one of which is the first Sound source signal distribution means is provided for inputting to one delay element group and inputting the other to the second delay element group.
[0013]
In the depth direction sound reproducing device according to the first aspect of the present invention, the sound source signal distributed to the first system is emitted into the space as a sound wave via the delay element group of the first system and the speaker, and at a certain position, that is, the focal position. It reaches almost the same time, and the energy ratio of the direct sound in the surrounding sound field is increased. As a result, the sound image can be localized at a short distance before the speaker. On the other hand, the sound source signal distributed to the second system is emitted as a sound wave that does not focus on the space via the delay element group of the second system and the speaker, and mainly enhances the indirect sound in the vicinity of the focus. .
[0014]
In general, it is known that the sense of distance of the sound image depends exclusively on the energy ratio of the direct sound and the indirect sound. However, if the level of the sound source signal distributed to the first system is increased, the direct sound near the focal point The ratio increases and the sound image is perceived at a short distance by the listener. Conversely, if the level of the sound source signal distributed to the second system is increased, the ratio of the indirect sound increases and the sound image moves from the focal point to the speaker side. It recedes and the listener perceives the sound image as moving away.
[0015]
Therefore, by adjusting the level distribution of the sound source signal with respect to the first system and the second system by the sound source signal distribution means, the listener can perceive the sound image at an arbitrary position ahead of the focal position as the depth direction. It is possible to control the sense of distance of the sound image from near to far.
[0016]
The sense of distance of the sound image is not based on the position of the focal point, but the delay amount of each delay element group of the first system and the second system is fixed, and the sound source signal for the first system and the second system is fixed by the sound source signal distribution means. Therefore, the sound images can be localized at different distances by differentiating the level distribution ratio of the two systems for each sound source, and a plurality of sound sources can be easily synthesized. .
[0017]
The depth direction sound reproducing device of the invention of claim 2 is arranged together with the first speaker for direct sound set so as to have a large directivity gain in the listening direction and the first speaker, and is maximum in the listening direction. The second speaker for indirect sound , which has no directivity gain and is set to generate reflected sound as indirect sound in the output space, and the sound source signal given from the outside to two outputs of arbitrary level ratio And a sound source signal distributing means for distributing, wherein the first speaker is driven by one output of the sound source signal distributing means and the second speaker is driven by the other output.
[0018]
In the depth direction sound reproducing apparatus according to the second aspect of the invention, the sound wave output from the first speaker directly reaches the listener from the front, and the sound wave output from the second speaker together with the reflected sound in the room. In other words, it reaches the position of the listener as an indirect sound. Therefore, the sound source has a sound image at an arbitrary position in the depth direction from the listening position to the speaker by arbitrarily adjusting the sound source level ratio distributed to the first speaker and the second speaker by the sound source signal distribution means. It can be perceived. In this case, since the reflected sound generated in the room is used as the indirect sound, the sense of distance of the sound image can be controlled while maintaining the natural tone color.
[0019]
A stereophonic sound reproducing device according to a third aspect of the present invention includes the depth direction sound reproducing device according to the first or second aspect on the left and right, and the sound source on the left side and the right side corresponding to the sound source signal input terminal of each depth direction sound reproducing device. A signal is input.
[0020]
In the stereophonic sound reproducing device according to the third aspect of the present invention, by using the first or second depth direction sound reproducing device, the distance control from the short distance to the far distance in the depth direction of the sound image is performed for each of the left and right sound sources. In addition, the sense of distance in the left-right direction can be controlled by the strength of the left and right sound sources, and the sense of distance of the three-dimensional sound image can be controlled.
[0021]
Moreover, if more depth direction sound reproducing apparatuses are used so that it can be easily inferred, it is possible to control the sense of distance of the rear sound image such as surround.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of a depth direction sound reproducing apparatus using the speaker array according to the first aspect of the present invention. The depth direction sound reproducing apparatus of the present invention includes a variable resistor 2 for distributing sound source signals inputted to one sound source signal input terminal 1 to two sound source signals having an arbitrary level ratio. By adjusting the resistance of the resistor 2, the sound source signal is distributed to the direct sound system 2a and the indirect sound system 2b at a predetermined level ratio.
The speaker array 3 is composed of a large number of speakers 4 to 6.
[0023]
On the direct sound system 2a side, focus delay elements 7 to 9 are connected to the speakers 4 to 9 so as to delay the outputs of the speakers 4 to 6 appropriately so that the sound waves output from the speaker array are focused at a position in space. 6 are provided in parallel, and adders 10 to 12 and amplifiers 13 to 15 are connected to the output sides of the focus delay elements 7 to 9, respectively, and the output sides of the amplifiers 13 to 15 are connected to the speaker 4. ~ 6 are connected to each.
[0024]
On the indirect sound system 2b side, there are provided in parallel as many non-focal delay elements 16-18 as the number of speakers 4-6 constituting the speaker array, and these output sides are connected to the adders 10-12, respectively. In addition, the signals are added to the outputs of the focus delay elements 7 to 9 and input to the amplifiers 13 to 15, respectively. The delay amount of each of the non-focus delay elements 16 to 18 is set so that the sound source signal on the side of the indirect sound system 2b is not focused anywhere when the sound source signal is amplified and output from the speakers 3 to 5. .
[0025]
For convenience of the following description, the whole including the delay elements 7 to 9, the adders 10 to 12, the amplifiers 13 to 15 and the delay elements 16 to 18 is collectively referred to as an electric system 19.
[0026]
Next, the operation of the depth direction sound reproducing apparatus having the above configuration will be described. The delay amounts of the focus delay elements 7 to 9 are set so that the focal points of the sound waves output from the speakers 3 to 5 are synthesized in front of the listener's eyes. On the other hand, the delay amounts of the non-focus delay elements 16 to 18 are set to random values so that the sound waves output from the speakers 3 to 5 do not synthesize the focus anywhere in the space. The sound source signal input to the sound source signal input terminal 1 is distributed with a desired level difference between the linear sound system 2a and the indirect sound system 2b by adjusting the resistance value of the variable resistor 2.
[0027]
Therefore, the sound source signal input to the sound source signal input terminal 1 has a predetermined level difference by the variable resistor 2, and each focus delay element 7-9 of the direct sound system 2a and each non-focus for the indirect sound system 2b. It is distributed to the delay elements 16-18. In the direct sound system 2a, a predetermined delay is applied by the focus delay elements 7 to 9, and the sound wave output from the speakers 3 to 5 becomes a direct sound focused on a predetermined spatial position, and in the indirect sound system 2b, A random delay is applied by the non-focus delay elements 16 to 18, and the sound waves output from the speakers 3 to 5 become indirect sounds that are not focused anywhere. The intensity ratio between the direct sound and the indirect sound varies depending on the level difference between the direct sound system 2a and the indirect sound system 2b by the variable resistor 2.
[0028]
If the level on the direct sound system 2a side is high now, the sound wave that contributes to the focus synthesis will be the main force, and if you listen near the focus, the direct sound will be dominant, and the sound image will be perceived at a short distance of the listener for hearing. . On the other hand, if the level on the indirect sound system 2b side is high, the sound pressure of the direct sound at the focal position becomes low, and the indirect sound becomes dominant and the sound image is perceived far away from the listener for audibility. become.
[0029]
Therefore, by adjusting the level difference between the direct sound system 2a and the indirect sound system 2b by the variable resistor 2, the sound image can be controlled to an arbitrary position from a short distance to a long distance of the listener in terms of audibility.
[0030]
Further, when the depth direction sound reproducing device of this embodiment is compared with the conventional two-channel stereo sound reproducing device shown in FIG. 6, the conventional method does not include a delay element in the direct sound reproducing path. In addition, even if a plurality of circuits having the configuration shown in FIG. 6 are used, the energy ratio between the direct sound and the indirect sound is not different from that in the case of one circuit, whereas in this embodiment, the number of speakers is increased. Can increase the energy ratio of the direct sound and make the sound image perceived at a closer distance.
[0031]
Next, one embodiment of the three-dimensional sound reproducing apparatus according to the invention of claim 3 will be described with reference to FIG. The stereophonic sound reproducing apparatus of this embodiment has the depth direction sound reproducing apparatus shown in FIG. 1 arranged on the left and right sides, and inputs the right sound source signal to the right sound source signal input terminal 1R and the left sound source signal to the left sound source signal input terminal 1L. Thus, the sound image position in the left-right direction is controlled along with the control of the sound image position in the depth direction.
[0032]
The orientations of the speaker arrays 3R and 3L are adjusted so that the sound waves of the direct sounds output from the left and right speaker arrays 3R and 3L are focused on the position in front of the listener 20.
[0033]
In this stereophonic sound reproducing device, by adjusting the left and right variable resistors 2R, 2L, the level distribution ratio between the direct sound systems 2Ra, 2La and the indirect sound systems 2Rb, 2Lb is adjusted to adjust the depth direction. By controlling the sense of distance of the sound image and adjusting the level difference between the sound source signals input to the left and right sound source signal input terminals 1R and 1L, the sound image position in the left and right direction can be controlled.
[0034]
Next, an embodiment of the depth direction sound reproducing apparatus of the invention of claim 2 will be described with reference to FIG. The depth direction sound reproducing apparatus according to this embodiment replaces the speaker array 3 with a large number of speakers 4 to 6 shown in FIG. 1, and a direct sound speaker 21 having a maximum directivity gain in the direction of the listening position, and a listening position. The indirect sound speaker 22 having the maximum directivity gain in the direction orthogonal to the listening direction is arranged close to each other, and the amplifiers 21 and 22 are connected to the speakers 21 and 22 via the amplifiers 23 and 24, respectively. The sound source signals of the direct sound system 2a and the indirect sound system 2b are input.
[0035]
The indirect sound speaker 22 has a structure in which the same types of speakers 22a and 22b arranged back to back are connected in opposite phases, and has bi-directionality having a null in the direction of the listening position.
[0036]
In the depth direction sound reproducing apparatus of this embodiment, the direct sound by the direct sound speaker 21 becomes dominant by increasing the level on the direct sound system 2a side by adjusting the variable resistor 2, and is close to the listener. By making the sound image perceived and conversely increasing the level on the indirect sound system 2b side, the indirect sound that reaches the listening position after the sound wave from the indirect sound speaker 22 is reflected on the wall of the room becomes dominant, and listening The person can perceive the sound image far away.
[0037]
Next, another embodiment of the depth direction sound reproducing apparatus according to the invention of claim 2 will be described with reference to FIG. The depth direction sound reproducing apparatus of this embodiment is configured such that an omnidirectional speaker 25 is arranged in place of the indirect sound speaker 22 shown in FIG. 3 and a sound source signal of the indirect sound system 2b is input. is there.
[0038]
In the depth direction sound reproducing apparatus of this embodiment, the sound image is perceived farthest when the level of the indirect sound system 22b is maximized and the level of the direct sound system 22a is minimized. Since the sound wave from the omnidirectional speaker 25 includes some components that directly reach the listening position, in this embodiment, the control range in the far direction of the sound image is limited, but the configuration is the simplest.
[0039]
Next, still another embodiment of the depth direction sound reproducing apparatus of the invention of claim 2 will be described with reference to FIG. In the depth direction sound reproducing apparatus of this embodiment, instead of the indirect sound speaker 22 shown in FIG. 3, an indirect sound speaker 26 having a maximum directivity gain is arranged in a direction other than the direction of the listening position. The sound source signal of the system 2b is input. The direction of the actual maximum directivity gain can be determined by adjusting so that the sound image is perceived farthest when reproduced by only the indirect sound speaker 26. The operation principle is the same as in the embodiment of FIG.
[0040]
In addition, by using two depth direction sound reproduction apparatuses shown in FIGS. 3 to 5 and arranging them in the left and right directions as shown in FIG. 2, a three-dimensional sound reproduction apparatus capable of controlling the sound image position in the left and right directions along with the depth direction is provided. Can be configured.
[0041]
【The invention's effect】
As described above, according to the first aspect of the present invention, the focus of the direct sound is set at the listening position, and the sense of distance in the depth direction is controlled by adjusting the energy ratio of the sound pressure to the indirect sound. It is possible to control the sense of distance of the sound image in the depth direction from near to far.
[0042]
In addition, the control of the sense of distance of a sound image by a set of speaker arrays is performed with two channels of a first system that mainly enhances direct sound and a second system that mainly enhances indirect sound, so that a speaker array is configured as in the past. As many channels as the number of speakers to be used are not required, and the number of channels can be significantly reduced.
[0043]
Further, since the sense of distance of the sound image is controlled by adjusting the level distribution ratio of the sound source signal between the first system and the second system, a different delay amount is provided for each sound image as in the sense of distance control of the sound image using a conventional speaker array. There is no need to set delay elements, and the number of delay elements does not become enormous, the number of delay elements can be constant regardless of the number of sound images, and for distance control of sound images as in the past. The delay amount of each delay element need not be variable, the delay amount of the delay element used in each system may be fixed, and the circuit configuration can be greatly simplified.
[0044]
According to the invention of claim 2, as in the invention of claim 1, each of the first speaker having a large directivity gain in the listening direction and the second speaker having a large directivity gain in a direction orthogonal thereto. Since the sense of distance of the sound image is controlled by adjusting the level distribution ratio of the sound source signals of the system, no delay element is required, and the circuit configuration can be greatly simplified.
[0045]
According to the third aspect of the present invention, the sense of distance in the left and right direction can be controlled together with the sense of distance in the depth direction, and the three-dimensional sense of distance of the sound image can be controlled.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram of one embodiment of a depth direction sound reproducing device of the present invention.
FIG. 2 is a circuit block diagram of one embodiment of the three-dimensional sound reproduction apparatus of the present invention.
FIG. 3 is a circuit block diagram of another embodiment of the depth direction sound reproducing device of the present invention.
FIG. 4 is a circuit block diagram of still another embodiment of the depth direction sound reproducing device of the present invention.
FIG. 5 is a circuit block diagram of still another embodiment of the depth direction sound reproducing device of the present invention.
FIG. 6 is a circuit block diagram of a conventional example.
FIG. 7 is a circuit block diagram of another conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Input terminal 2 Variable resistor 2a Direct sound system 2b Indirect sound system 3 Speaker array 4-6 Speaker 7-9 Focus delay element 10-12 Adder 13-15 Amplifier 16-18 Delay element 19 Electrical system 20 Listener 21 , 22 Speaker 23, 24 Amplifier 25, 26 Speaker

Claims (3)

A plurality of speakers each provided with two delay elements, a first system for direct sound and a second system for indirect sound, are distributed,
The amount of delay of the delay element group of the first system is set so that the sound wave output from each speaker generates a sound wave that focuses on a certain position in space as a direct sound,
The delay amount of the delay element group of the second system is set to a random value so that the sound wave output from each speaker generates a sound wave that is not focused as an indirect sound,
Sound source signal distribution means for distributing sound source signals given from the outside to two outputs having an arbitrary level ratio, one of which is input to the first delay element group, and the other input to the second delay element group Depth direction sound reproducing device. A first speaker for direct sound set to have a large directivity gain in the listening direction;
A second speaker for indirect sound that is arranged together with the first speaker and has no maximum directivity gain in the listening direction and is set to generate reflected sound as indirect sound in the output space;
Sound source signal distribution means for distributing sound source signals given from the outside to two outputs having an arbitrary level ratio;
A depth direction sound reproducing apparatus in which the first speaker is driven by one output of the sound source signal distribution means and the second speaker is driven by the other output.   3. A stereophonic sound reproduction comprising the depth direction sound reproduction apparatus according to claim 1 on the left and right sides, and inputting a sound source signal corresponding to each of the left and right sides to a sound source signal input terminal of each depth direction sound reproduction apparatus. apparatus.

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