JP5416044B2 - Local regeneration system - Google Patents

Description

  The present invention relates to a local reproduction system in which a listening area is provided in a specific area by using a directional speaker and sound reflection.

  There is a technology for reproducing sound only at a specific place by using a directional speaker in voice guidance in an exhibition hall or a train platform. By giving the audible sound super directivity, the audible sound can be limited to a local area called an audio spot like a light spotlight. However, if no contrivance is made before the direction of the directional speaker, the acoustic signal radiated from the directional speaker 70 is reflected by the wall or floor as shown in FIG. 7, and the audible area is enlarged. There is a case.

  Thus, the idea of constructing an audio spot at an arbitrary position by combining a directional speaker and a reflector is disclosed in Non-Patent Document 1, for example. FIG. 8 shows an experimental layout shown in Non-Patent Document 1. 8 shows a result of good sound localization in a direction of 30 ° when a rectangular pyramid reflector having a bottom surface of 40 cm × 40 cm and a height of 20 cm is arranged as a reflector at the position of the metal plate in FIG. ing.

Kotaro Ninagawa, Masamasa Mori, Takanobu Nishiura, “Measures and Characteristic Evaluation of Reflective Objects for Wall Reflective Audio Spots”, Acoustical Society Proceedings, pp.675-676, Mar. 2010.

  In the conventional method of constructing an audio spot with a directional speaker and a reflecting object, it is necessary to change the shape of the floor and the wall, so that there is a problem that the installation cost is greatly increased. Moreover, even when the reflecting object is movable, there is a problem that the condition setting cannot be automatically performed.

  The present invention has been made in view of such a problem, and an audio spot can be constructed at an arbitrary position at a low installation cost by using a local reproduction system including a sound emitting part and a reflected sound part. An object of the present invention is to provide a local reproduction system capable of automatically building an audio spot.

  The local reproduction system according to the present invention includes a sound emitting part and a reflected sound part. The sound emitting unit includes a directional speaker, sound receiving means for directivity control, and sound emission directivity control means. The directivity control sound receiving means is disposed at a fixed position in front of the directional speaker, and receives the radiated sound reception signal of the radiated sound radiated from the directional speaker and the reflected sound reflected by the reflected sound portion. The sound emission directivity control means controls the directivity of the directional speaker so that the radiation reception signal is maximized. The reflection sound unit includes a reflection direction control sound receiving unit and a reflection direction control unit. The reflection direction control sound receiving means is disposed in front of the reflection plate and receives a reflected sound reception signal of the radiated sound of the directional speaker and the reflection sound reflected by the reflection plate. The reflection direction control means controls the shape of the reflection surface of the reflection plate, the direction of the reflection surface, or the shape and direction of the reflection surface so that the reflected sound reception signal is maximized.

  In the local reproduction system of the present invention, the sound emitting unit controls the directivity direction of the directional speaker so that the radiation reception signal of the radiated sound from the directional speaker and the reflected sound from the reflected sound unit is maximized. Then, the shape and direction of the reflecting plate are controlled so that the reflected sound of the reflected sound of the reflected sound reflected from the directional speaker and the reflected sound reflected by the reflecting plate is maximized. Therefore, an audio spot can be automatically constructed between the sound emitting part and the reflected sound part.

  In addition, since it is not necessary to change the shape of the wall or floor of the room, an audio spot can be constructed at an arbitrary position at low cost.

The figure which shows the function structural example of the local reproduction | regeneration system 100 of this invention. It is a figure which shows the example of the directional speaker 11 and the sound reception means 12 for directivity control, (a) is an example using the one point stereo microphone 120, (b) is a figure which shows the example using four microphones 121. It is. The figure which shows the function structural example for changing the shape of the reflecting plate. It is a figure which shows the example which changed the shape of the reflecting plate 21, (a) is an example made into convex shape, (b) is a figure which shows the example made into concave shape. The figure which shows the operation | movement flow of a relative direction search process. The figure which shows the example which provided the sound-absorbing object 14 around the directional speaker. The figure which shows notionally the mode that the sound wave radiated | emitted from the directional speaker is reflected and scattered by a floor. The figure which shows the experiment arrangement | positioning drawing shown by the nonpatent literature 1. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals are given to the same components in a plurality of drawings, and the description will not be repeated.

  FIG. 1 shows an example of the functional configuration of the local reproduction system 100 of the present invention. The local reproduction system 100 includes a sound emitting unit 10 and a reflected sound unit 20. The sound emitting unit 10 includes a directional speaker 11, directivity control sound receiving means 12, and sound emission directivity control means 13.

  The directional speaker 11 is a known speaker capable of changing the directivity of a radiated acoustic signal, such as a horn speaker, a parametric speaker, or a digital filter type speaker array. This radiated acoustic signal is hereinafter referred to as radiated sound. The directivity control sound receiving means 12 is arranged at a fixed position in front of the directional speaker 11 and receives a radiated sound reception signal of a radiated sound radiated from the directional speaker 11 and a reflected sound reflected by the reflection sound portion. Sound. The sound emission directivity control means 13 controls the directivity of the directional speaker 11 so that the radiation reception signal is maximized.

  The reflection sound unit 20 includes a reflection plate 21, a reflection direction control sound receiving unit 22, and a reflection direction control unit 23. The reflector 21 reflects the radiated sound radiated from the sound emitting unit 10. The reflection direction control sound receiving means 22 is disposed in front of the reflection plate 21 and receives a reflected sound reception signal of the radiated sound of the directional speaker 11 and the reflection sound reflected by the reflection plate 21. The reflection direction control means 23 controls the shape and direction of the reflection surface of the reflection plate 21 so that the reflected sound reception signal is maximized.

  By operating the sound emitting unit 10 and the reflected sound unit 20 as described above, an audio spot can be automatically constructed between the sound emitting unit 10 and the reflected sound unit 20. In the example of FIG. 1, a range indicated by a broken line is a listening area between the sound emitting unit 10 and the reflected sound unit 20. Hereinafter, the present invention will be described in more detail by showing more specific functional configuration examples of the respective units.

[Directional speaker and sound receiving means for directivity control]
FIG. 2 shows a more specific configuration example of the directional speaker 11 and the directivity control sound receiving means 12. FIG. 2A shows an example in which a one-point stereo microphone 120 is used as the directivity control sound receiving means 12. FIG. 2B shows an example using four microphones 121a to 121d. Each figure is a diagram seen from the front of the directional speaker 11, and shows an example in which the directional speaker 11 is a digital filter type speaker array including a plurality of speakers 11a to 11q.

  The digital filter type loudspeaker array is a well-known technique for changing the directivity of radiated sound by controlling the delay amount and amplitude amount of signals input to the speakers 11a to 11q.

  In FIG. 2A, the one-point stereo microphone 120 is disposed in the approximate center in front of the 16 speakers 11 a to 11 q constituting the directional speaker 11. Even if the directivity direction of the radiated sound from the directional speaker 11 changes, the position of the one-point stereo microphone 120 is fixed, and the change in the directional direction of the radiated sound and the reflected sound from the reflected sound unit 20 are received. .

  FIG. 2B shows two microphones on two axes orthogonal to the front of the center point of the 16 speakers 11 a to 11 q constituting the directional speaker 11, at a position equidistant from the center. 121b and 121d and microphones 121a and 121c are arranged. Even if the directivity direction of the radiated sound from the directional speaker 11 changes, the positions of the four microphones 121a to 121d are fixed, and the change in the directional direction of the radiated sound and the reflected sound from the reflected sound unit 20 are received. Sound.

  The position of the microphone is not limited to the above example. If two or more microphones are arranged at a fixed position in front of the directional speaker 11, the change in directivity of the radiated sound can be detected, and the reflected sound reflected by the radiated sound and the reflected sound unit 20. It is possible to receive a radiation reception signal composed of sound.

  The radiation reception signal is input to the sound emission directivity control means 13, and the sound emission directivity control means 13 controls the directivity direction of the directional speaker 11 so that the radiation reception signal is maximized. The sound emission directivity control means 13 changes the directivity direction of the directional speaker 11 constituted by, for example, a digital filter type speaker array by controlling the delay amount and the amplitude amount of a signal input to each speaker. The sound emission directivity control means 13 can be easily realized by a known technique.

〔reflector〕
Here, a method for controlling the shape of the reflecting plate 21 will be described. FIG. 3 shows a functional configuration example of the shape control means 30 that controls the shape of the reflection plate 21 included in the reflection sound unit 20. Since the portion for controlling the direction of the reflecting plate 21 can be realized by a general method, it is omitted in FIG. 3, and only the configuration for controlling the shape of the reflecting plate 21 is shown. FIG. 3 is a view of the reflector 21 as viewed from the side.

  The shape control means 30 includes reflector fixing frames 24a and 24b, a bending drive motor 25, a bending shaft 26, a bending direction initialization motor 27, and an initialization shaft 28. The upper and lower ends of the reflector 21 in the vertical direction are held by the reflector fixing frames 24a and 24b. One reflector fixing frame 24 a is connected to a bending drive motor 25 via a bending shaft 26. As the bending drive motor 25 rotates, the vertical position of the reflector fixing frame 24a moves up and down.

  The reflecting plate 21 is made of, for example, a deformable thin metal plate or a plastic material such as an underlay, and can be deformed by lowering the position of the reflecting plate fixing frame 24a. An initialization shaft 28 is connected to a substantially central surface of the reflecting plate 21, and the initialization shaft 28 can be moved back and forth by a bending direction initialization motor 27.

FIG. 4 shows a case where the reflecting plate 21 is deformed into a convex surface (FIG. 4A) and a concave surface (FIG. 4B). When making the shape of the reflecting plate 21 convex, the bending direction initialization motor 27 drives the initialization shaft 28 forward at the same time as or before the bending drive motor 25 starts to rotate. Thereafter, the initialization shaft 28 is brought into a free state without applying a driving force. Such switching of the state can be easily realized by configuring the bending method initialization motor 27 with, for example, a linear motor.
And the reflecting plate 21 can be deform | transformed into a convex surface by the position of the reflecting plate fixing frame 24a falling.

  When the shape of the reflector 21 is concave, the bending direction initialization motor 27 drives the initialization shaft 28 rearward at the same time or before the bending drive motor 25 starts to rotate. Thereafter, the initialization shaft 28 is brought into a free state without applying a driving force. In this state, when the position of the reflector fixing frame 24a is lowered, the reflector 21 is deformed into a concave surface.

  As described above, the shape of the reflecting plate 21 can be freely deformed from a flat surface to a convex surface and from a flat surface to a concave surface. By utilizing the change in the shape of the reflecting plate 21, an audio spot can be efficiently configured.

  In the local reproduction system 100 of the present invention, the radiated sound unit 10 emits radiated sound in the direction of the reflected sound unit 20, and the reflected sound unit 20 needs to direct the reflecting plate 21 in the direction in which the radiated sound comes. The sound emitting directivity control means 13 and the reflection direction control means 23 control the directivity direction of the directional speaker 11 and the direction of the reflector 21 so that each of the radiation sound reception signal and the reflection sound reception signal is maximized. By doing so, the radiated sound and the reflected sound are automatically opposed to each other. This relative operation is always performed when the local reproduction system 100 is installed.

  FIG. 5 shows an operation flow of a relative direction search operation in which the radiated sound and the reflected sound are automatically opposed to each other. When the local reproduction system is installed, it is easier to find the relative direction if the reflected sound is initially diffused. Therefore, in the initial stage of searching for the relative direction, it is convenient to place the reflecting plate 21 in a convex shape (step S30). Then, the direction of the reflecting plate 21 is fixed, and the directivity direction of the directional speaker 11 is determined in the direction in which the radiation sound reception signal is maximized (step S13). Thereafter, the shape of the reflecting plate 21 is changed to a plane step by step (step S31).

  After changing the shape of the reflecting plate 21 by one step, the direction of the reflecting plate 21 is controlled so that the reflected sound signal is maximized by changing the direction of the reflecting plate 21 while the shape of the reflecting plate 21 is fixed (step S23). By repeating the operations of step S13, step S31, and step S23 until the reflected sound reception signal becomes maximum, the radiated sound and the reflected sound can be made to be opposite (Yes in step S24). In this way, the audio spot can be efficiently configured by changing the shape of the reflector 21. In addition, when it is desired to make the audio spot a more limited area, the reflector 21 may be concave. The cooperation of the relative direction search operation in the sound emitting unit 10 and the reflected sound unit 20 is performed by connecting the sound emitting unit 10 and the reflected sound unit 20 with a signal line (broken line connecting 13 and 23 in FIG. 1). It can be easily realized by communicating the operation status to the other party. The communication by the wired connection may be replaced with infrared communication or short-range wireless communication.

  Note that the directivity control sound receiving means 12 of the sound emitting unit 10 also receives a sound wave whose reflected sound is further reflected by the directional speaker 11. The smaller the amount of sound waves reflected by the directional speaker 11, the higher the accuracy of the relative direction search. Therefore, as shown in FIG. 6, it is effective to cover the portion of the directional speaker 11 except the front surface in the sound emission direction with the sound absorbing object 14. Since the reflected sound is absorbed by the sound absorbing object 14, the directivity control sound receiving means 12 can receive only the reflected sound from the pure reflected sound unit 20.

  As described above, the local reproduction system including the sound emitting unit 10 and the reflected sound unit 20 can automatically construct an audio spot at an arbitrary position at low cost without changing the shape of the floor or wall of the room. I can do it.

  In addition, although the relative direction search operation | movement which makes the sound emission part 10 and the reflected sound part 20 face at the time of installation of a local reproduction | regeneration system was demonstrated, you may make it abbreviate | omit the operation | movement when each position is known. When the positional relationship between the directional speaker 11 and the reflected sound unit 20 is known, the relative direction searching operation can be omitted, and the reflector 21 is not limited to one that can control the shape.

Claims (3)

A local reproduction system comprising a sound emission part and a reflection sound part,
The sound emission part
A directional speaker that emits an acoustic signal with directivity;
Sound receiving means for directivity control disposed at a fixed position in front of the directional speaker and receiving a radiated sound signal of a radiated sound radiated from the directional speaker and a reflected sound reflected by a reflected sound portion; ,
Sound emission directivity control means for controlling the directivity of the directional speaker so that the radiation sound reception signal is maximized;
Comprising
The reflected sound part
A reflector that reflects the radiated sound;
A reflection direction control receiving means for receiving a radiated sound of the directional speaker and a reflected received signal of the reflected sound reflected by the reflecting plate, disposed in front of the reflecting plate;
Reflection direction control means for controlling the shape of the reflecting surface of the reflecting plate, the direction of the reflecting surface, or the shape and direction of the reflecting surface so that the reflected sound receiving signal is maximized;
A local reproduction system comprising: In the local reproduction | regeneration system of Claim 1,
The reflected sound part is
A local reproduction system comprising shape control means for changing the shape of the reflecting surface of the reflecting plate until the reflected sound receiving signal becomes maximum. The local reproduction system according to claim 1 or 2,
A local reproduction system, wherein a portion of the directional speaker other than the front surface in the sound emission direction is covered with a sound absorbing object.

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