JP2012005083A - Acoustic space reproducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of microphones and speakers while reproducing a sound field with reality for a moving listener or listeners distributed in a wide area.SOLUTION: The acoustic space reproducer causes speaker units 3 to reproduce a sound collected by sets of microphone units 1 arranged at a plurality of sound collecting points disposed separately from each other. The speaker units 3 are arranged separately from each other in a manner relatively identical to the collecting points of the microphone units 1. The microphone units 1 and the speaker units 3 comprise at least three sets of microphones 5 and speakers 6 having directivity, which are arranged so that the directivity directions are radial in the horizontal plane. An arrangement is adopted such that the speakers 6 emit sound in the directions that are relatively identical to the respective directivity directions of the microphones 5, the propagation directions of the acoustic waves emitted by the speakers 6 are opposite to the respective propagation directions of the acoustic waves collected by the microphones 5.

Description

  The present invention relates to an acoustic space reproduction device that reproduces sound recorded by a plurality of microphones using a plurality of speakers, and more particularly to an acoustic space reproduction device that is optimal for a reproduction device that allows a moving listener to hear a sound and accurately recognize a sound source. .

  A reproducing apparatus has been developed in which directional microphones are arranged in a radial direction and a sound collected by each microphone is reproduced by a plurality of speakers. (See Patent Document 1)

  As shown in FIG. 1, the reproducing apparatus described above arranges a plurality of directional microphones 20 at predetermined sound pickup points 23 in a sound field so that the directional directions are radially directed, and the directional microphones 20 simultaneously. And record the sound independently. The recorded sound is reproduced by the same number of speakers 21 as the number of directional microphones 20. The plurality of speakers 21 are arranged around the listener 22 and radiate sound toward the listener 22 from the surroundings. The direction in which each speaker 21 emits sound is arranged so as to be relatively the same as the direction of the directional microphone 20 that picks up the sound. That is, with the traveling direction of the sound collected by the directional microphone 20 and the traveling direction of the sound emitted from the speaker 21 toward the listener 22 being the same direction, the sound collected by the directional microphone 20 is the listener 22. Radiates sound toward

Japanese Patent Laid-Open No. 11-262097

  The above reproducing apparatus can reproduce the sound collected by the directional microphone 20 in a preferable state for the listener 22 arranged at a specific position. However, a moving listener or a large number of listeners distributed over a wide area has a drawback that it is difficult to reproduce sound while the sound source is accurately localized.

  A playback device that can accurately recognize the position of a sound source while a listener moves is used to perform an evaluation experiment on an acoustic signal device at an intersection provided for a hearing impaired person, for example. For the evaluation test, it is necessary to accurately reproduce the environmental noise around the intersection in the pedestrian crossing area. If the pedestrian can generate noise in the same state as when a pedestrian passes an actual pedestrian crossing with an acoustic space playback device, it can be used by using the playback device installed indoors without using the actual pedestrian crossing. It is possible to conduct an evaluation experiment on acoustic signals for the hearing impaired, simulating the sound environment at the intersection. In this experiment, it is important that the hearing impaired person who is a listener can hear noise in the same state as the actual intersection at any position on the pedestrian crossing. An accurate evaluation experiment cannot be performed if the actual sound field such as an actual intersection or pedestrian crossing cannot be reproduced realistically. In particular, if the sound field heard by a pedestrian moving on a pedestrian crossing is unnatural, an accurate evaluation test cannot be performed.

  2. Description of the Related Art Conventionally, an acoustic space reproduction device that reproduces a sound field for a moving listener with hearing impairment has been developed as shown in FIG. This playback apparatus records a sound by arranging a plurality of microphones 30 at a predetermined interval, and plays back a sound recorded by a speaker 31 disposed at a position relative to the microphone 30. This acoustic space reproduction device not only requires a large number of microphones 30 and speakers 31 but also cannot reproduce the actual sound field in the field such as an actual intersection or pedestrian crossing. There is a drawback that the reproduction of the sound field heard by the pedestrian's ear is unnatural. This drawback can be reduced by increasing the number of microphones and speakers, that is, by narrowing the interval at which the microphones are arranged and also by reducing the interval between the speakers. However, when the number of microphones and speakers is increased, there is a disadvantage that the reproducing apparatus becomes complicated and expensive.

  Even when the listener is not moving, the same problem occurs even when the sound source is accurately localized and reproduced by many listeners arranged so as to be distributed over a wide area.

  The present invention has been developed for the purpose of solving the above drawbacks. An important object of the present invention is to provide an acoustic space reproduction device that can reduce the number of microphones and speakers while realistically reproducing a sound field for a moving listener or a listener distributed over a wide area.

Means for Solving the Problems and Effects of the Invention

  The acoustic space reproduction apparatus of the present invention records a plurality of sets of microphone units 1 arranged at a plurality of sound collection points 4 arranged apart from each other, and an electrical signal collected by the plurality of sets of microphone units 1. A recorder 2 and a plurality of sets of speaker units 3 that are arranged apart from each other at a plurality of positions for reproducing signals recorded by the recorder 2 are provided. The plurality of sets of speaker units 3 are disposed at the same position relative to the sound pickup points 4 of the plurality of sets of microphone units 1. The microphone unit 1 includes three or more sets of directional microphones 5 that are arranged so that the directing directions are radially directed in a horizontal plane.

  The speaker unit 3 includes a plurality of speakers 6 that emit sound waves in the directivity direction of each microphone unit 1, and the direction in which each speaker 6 emits sound is relatively the same as the directivity direction of the microphone 5. In addition, the traveling direction of the sound wave emitted from the speaker 6 is opposite to the traveling direction of the sound wave collected by the microphone 5.

  In the above reproducing apparatus, the sound collected by each microphone 5 of the microphone unit 1 arranged at the plurality of sound collection points 4 is arranged at a position corresponding to the sound collection point 4 of the microphone 5. Radiates from the speaker 6 of the speaker unit 3.

  The acoustic space reproduction device described above has a feature that the number of microphones and speakers can be reduced while realistically reproducing the sound field for a moving listener or a listener distributed over a wide area. This is because the above-described acoustic space reproduction device is configured by a plurality of three or more sets of microphones in which a plurality of sets of microphone units and speaker units are disposed at the same relative positions apart from each other, and the microphone units are radially directed. This is because the speaker unit is composed of three or more sets of speakers that emit sound waves in the same direction as the direction of the microphone and radiate in the opposite direction to the direction of sound waves collected by the microphone. The speaker unit of the acoustic space reproduction device of the present invention does not radiate sound waves from each speaker toward the sound collection point of the microphone. Each speaker radiates sound waves in a radially large area. Therefore, it is possible to reproduce the sound field realistically for a listener who moves over a wide area and using a small number of speakers.

  A conventional reproducing apparatus in which a large number of speakers are arranged close to each other emits sound from a large number of speakers and reproduces a sound field in a wide area. When a listener listens to sound emitted from a large number of speakers, it becomes difficult to accurately recognize the position of the sound source. That is, the localization of the sound source becomes unclear. This is because the listener listens to the synthesized wave of the sound having a phase difference reproduced from each speaker.

  On the other hand, the above acoustic space reproducing apparatus can radiate sound over a wide area while widening the interval between the speaker units, so that the number of speaker units can be reduced. In addition, all the speakers in the speaker unit do not radiate sound toward the sound collection point of the microphone, but radiate sound in different directions radially, so that sound is emitted to listeners who move or are distributed over a wide area. it can. This playback apparatus has a small number of speakers heard by listeners who are moving or distributed over a wide area, and can accurately reproduce the localization of the sound source. This is because a large number of sounds having phase differences are synthesized from a large number of speakers and are not input to the ear. This is extremely important for conducting an evaluation experiment on an acoustic signal device at an intersection. This is because, for the evaluation test, it is necessary to accurately reproduce the environmental noise around the intersection in the pedestrian crossing area. If the pedestrian can generate noise in the same state as when a pedestrian passes an actual pedestrian crossing with an acoustic space playback device, it can be used by using the playback device installed indoors without using the actual pedestrian crossing. It is possible to effectively carry out an evaluation experiment of an acoustic signal device for a hearing impaired person simulating the sound environment of the intersection. Even in a device that reproduces a sound field such as a musical instrument over a wide area, it is important that the localization of each musical instrument can be accurately expressed.

The acoustic space reproduction device according to the second aspect of the present invention includes two sets of microphone units 1 and two sets of speaker units 3 that are arranged apart from each other, and two sets of microphone units 1 are provided for each microphone. The unit 1 is arranged so that the directivity direction is directed to one of the line segments connecting the sound pickup points 4 of the unit 1.
The above acoustic space reproduction device can reproduce a realistic sound field for a listener who moves and a listener distributed over a wide area with only two microphone units and speaker units.

In the acoustic space reproduction device according to the third aspect of the present invention, the microphone unit 1 includes three sets of directional microphones 5 and the speaker unit 3 includes three sets of speakers 6.
The above acoustic space reproduction device can reproduce a realistic sound field for a listener who moves and a listener distributed over a wide area, with three sets of microphones constituting a microphone unit and speakers constituting a speaker unit.

In the acoustic space reproduction device according to the fourth aspect of the present invention, the microphone unit 1 has the shielding plates 7 provided radially between the adjacent microphones 5, and the microphones 5 are arranged between the shielding plates 7.
The above acoustic space reproduction device can improve the directional characteristics of a microphone while using a non-directional microphone, or can further sharpen the directional characteristics of a directional microphone.

In the acoustic space reproducing device according to the fifth aspect of the present invention, a listener who hears sound reproduced from the speaker unit 3 is a moving subject.
The above acoustic space reproduction device has a feature that it can accurately reproduce the environmental noise around the intersection in an area such as a pedestrian crossing. This is because noise can be generated in the same state as when a pedestrian passes an actual pedestrian crossing.

It is a schematic block diagram which shows the conventional acoustic space reproducing | regenerating apparatus. It is a schematic block diagram which shows the other conventional acoustic space reproducing | regenerating apparatus. It is a schematic block diagram which shows the acoustic space reproducing | regenerating apparatus concerning the 1st Example of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows the acoustic space reproducing | regenerating apparatus concerning the 1st Example of this invention. It is a perspective view which shows an example of the cabinet of a speaker unit. It is a schematic block diagram which shows the acoustic space reproducing | regenerating apparatus concerning the 2nd Example of this invention. It is a schematic block diagram which shows the acoustic space reproducing | regenerating apparatus concerning the 2nd Example of this invention. It is a schematic block diagram which shows the acoustic space reproducing | regenerating apparatus concerning the 3rd Example of this invention. It is a schematic block diagram which shows the acoustic space reproducing | regenerating apparatus concerning the 3rd Example of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below exemplifies an acoustic space reproducing device for embodying the technical idea of the present invention, and the present invention does not specify the acoustic space reproducing device as follows. Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The acoustic space reproduction device shown in FIGS. 3 and 4 is picked up by two sets of microphone units 1 arranged at two sets of sound pickup points 4 arranged apart from each other and two sets of microphone units 1. A recorder 2 that records electrical signals and two sets of speaker units 3 that are arranged apart from each other at a plurality of positions where the signals recorded by the recorder 2 are reproduced are provided. FIG. 3 shows the microphone unit 1 and the recorder 2, and FIG. 4 shows the speaker unit 3 and the recorder 2.

  In the reproducing apparatus, the sound collection points 4 of the two sets of microphone units 1 and the two sets of speaker units 3 are disposed relatively apart from each other at the same position. In the playback apparatus of FIG. 3, since the microphone unit 1 is linearly spaced apart, the speaker unit 3 is also linearly spaced relatively at the same position. The two sets of microphone units 1 set the interval between the sound pickup points 4 to 4 mails. Therefore, the speaker unit 3 can reproduce the same sound as the sound collected by the microphone unit 1 with the center interval being 4 mails. However, the interval between the speaker units is not necessarily 4 emails. This is because the two sets of speaker units can be arranged at the same position relative to the sound collection points of the microphone units arranged in a straight line by arranging them apart in a straight line.

  The microphone unit 1 includes three or more sets of directional microphones 5 arranged in a radial direction in a horizontal plane. In the reproducing apparatus of FIG. 3, three sets of microphones 5 are arranged with their directing directions radially directed. That is, the directivity direction of the center microphone 5 is arranged forward, and the directivity directions of the left and right microphones 5 are arranged at an angle of 60 degrees with respect to the directivity direction of the center microphone 5. The playback device of FIG. 3 is arranged as a microphone unit 1 so that the directivity directions of the three sets of microphones 5 are radial, but the microphone unit has four or more sets of microphones arranged so that the directivity directions are radial. You can also. Preferably, the microphone unit arranges an odd number of microphones in a radial direction. A microphone unit that arranges an odd number of microphones in a radial direction can be set to the front of the central microphone.

  In the microphone unit 1 of FIG. 3, a shielding plate 7 is provided radially between adjacent microphones 5, the microphones 5 are arranged between the shielding plates 7, and the directivity directions of the three sets of microphones 5 are made radial. In the illustrated microphone unit 1, microphones 5 are arranged between four shielding plates 7 arranged radially at an angle of 60 degrees. The shielding plate 7 is a soft plastic foam having open cells with numerous irregularities on the surface so as not to reflect sound on the surface. A soft urethane foam is optimal for the plastic foam. The shielding plate 7 has a horizontal width and a vertical width of 50 cm to 200 cm. The shielding plate 7 can improve the directivity to a lower frequency as the horizontal width and vertical width are increased. The microphone unit 1 can control the directivity of the microphone 5 by the angle of the shielding plate 7. In the microphone unit 1 of FIG. 3, the angle of the shielding plate 7 is 60 degrees, but the angle between the two shielding plates arranged in the center can be 30 degrees to 90 degrees.

  The microphone unit 1 that improves the directional characteristics of the microphone 5 with the shielding plate 7 can control the directional characteristics by using a non-directional microphone 5 to be used. However, the directivity characteristics of each microphone 5 can be made sharper by using a microphone having directivity. The microphone unit can use a directional microphone and omit the shielding plate. Directive microphones are arranged so that the directivity direction is radial.

  The sound signal output from each microphone 5 is recorded in the recorder 2. The recorder 2 amplifies the output signal of the microphone 5 with the amplifier 8, converts it into a digital signal with the A / D converter 9, and records it in the storage unit 10. The storage unit 10 is a storage medium such as a semiconductor memory, CD, or DVD.

  The speaker unit 3 includes a plurality of speakers 6 that emit sound waves in the directivity direction of each microphone unit 1. Since the microphone unit 1 in FIG. 3 sets the angle of the directivity of the three sets of microphones 5 to 60 degrees, the speaker unit 3 in FIG. 4 also emits sound from the three sets of speakers 6 at an angle of 60 degrees. That is, the direction in which each speaker 6 emits sound is the same as the direction in which the microphone 5 is directed, and is emitted from the speaker 6 with respect to the traveling direction of the sound wave collected by the microphone 5. It arrange | positions so that the advancing direction of a sound wave may become a reverse direction.

  However, in this specification, “the direction in which each speaker emits sound is the same relative to the direction of the microphone” means that the direction of orientation of the microphone and the speaker is completely the same. It is not specified as a state, and is used to include a state in which the directivity direction of the speaker is deviated ± 30 degrees from the directivity direction of the microphone. This is because such a deviation in the direction of directivity between the microphone and the speaker does not affect the reproduction of the sound field.

  As shown in FIG. 5, the speaker unit 3 has a shape in which the front panel 12 of the cabinet 11 is inclined so that each speaker 6 emits sound at an angle of 60 degrees. That is, the front panel 12 inclines the side panel 12B at an angle of 60 degrees with respect to the center panel 12A. Further, in order to improve the directivity of the speaker 6, the speaker unit 3 of FIG. 4 is also provided between the central panel 12 </ b> A and the side panel 12 </ b> B and between the side panel 12 </ b> B and the side panel 13 of the cabinet 11. A shielding plate 14 is arranged. The shielding plates 14 at the corners of the central panel 12A and the side panel 12B are arranged at the same angle with respect to the central panel 12A and the side panel 12B, and the side panel 12B as the front panel 12 and the cabinet 11 are arranged. The shielding plate 14 disposed between the side panel 13 and the side panel 13 is arranged in a straight line with the two shielding plates 14 in a posture orthogonal to the side panel 13.

  The speaker unit 3 described above is provided with a shielding plate 14 to improve the directivity characteristics of each speaker 6. However, since the speaker has a directional characteristic that emits sound more strongly in the front surface without the shielding plate, it is not always necessary to provide the shielding plate.

  3 and 4, the sound collected by each microphone 5 of the microphone unit 1 arranged at the sound collection point 4 is arranged at a position corresponding to the sound collection point 4 of the microphone 5. By radiating from each speaker 6 of the speaker unit 3, the localization of the sound source is made clearer and a realistic sound field is reproduced.

  Further, in the playback device of FIGS. 6 and 7, four sets of microphone units 1 and speaker units 3 are arranged in two rows. One row of microphone units 1 and speaker units 3 arranged in a straight line are arranged in the same manner as the reproducing apparatus shown in FIGS. The two rows of the microphone units 1 and the speaker units 3 are arranged so as to face each other. Since this reproducing apparatus reproduces sound by the four sets of the microphone unit 1 and the speaker unit 3, the sound field can be reproduced realistically in a wider area.

  The reproduction apparatus shown in FIGS. 3 to 7 is most suitable for an evaluation experiment of an acoustic signal device at an intersection provided for a hearing impaired person. These reproducing apparatuses can accurately reproduce the environmental noise around the intersection in the area of the pedestrian crossing by arranging the microphone unit 1 and the speaker unit 3 on the side of the road. In other words, with the acoustic space reproduction device shown in these figures, a noise is generated in the same state as when a pedestrian passes an actual pedestrian crossing, and reproduction provided indoors without using the actual pedestrian crossing. Using the device, it is possible to conduct an evaluation experiment on an acoustic signal device for a hearing impaired person that simulates the sound environment of an actual intersection. In particular, this reproduction apparatus has a feature that a hearing-impaired person can hear noise in the same state as an actual intersection at any position on a pedestrian crossing.

  FIGS. 8 and 9 are suitable for reproducing a performance of an orchestra recorded in the music hall 15 at home or in the hall. In this playback apparatus, the microphone unit 1, the speaker unit 3, and the recorder 2 have the structure shown in FIGS. 3 and 4. However, since the home to be played is narrower than the music hall to be recorded, the microphone unit 1 and the speaker are used. The units 3 are arranged in a straight line and are arranged at the same position relative to each other, but the intervals of the speaker units 3 are arranged to be narrower than the intervals of the sound collecting points 4 of the microphone unit 1. That is, the interval between the speaker units 3 is adjusted to an optimum interval for the size of the area for reproducing the sound.

  The above reproducing apparatus can reproduce the sound field recorded in the wide music hall 15 realistically at home.

  The acoustic space reproduction apparatus of the present invention is used to conduct an evaluation experiment of an acoustic signal device at an intersection provided for a hearing impaired person, and accurately corrects environmental noise around the intersection in the pedestrian crossing area in the laboratory. Can be reproduced.

DESCRIPTION OF SYMBOLS 1 ... Microphone unit 2 ... Recorder 3 ... Speaker unit 4 ... Sound pick-up point 5 ... Microphone 6 ... Speaker 7 ... Shield plate 8 ... Amplifier 9 ... A / D converter 10 ... Memory | storage part 11 ... Cabinet 12 ... Front panel 12A ... Center panel
12B ... side panel 13 ... side panel 14 ... shielding plate 15 ... music hall 20 ... directional microphone 21 ... speaker 22 ... listener 23 ... sound pickup point 30 ... microphone 31 ... speaker

Claims (5)

A plurality of microphone units (1) arranged at a plurality of sound collection points (4) arranged apart from each other, and a recorder (2) that records the electrical signals collected by the plurality of microphone units (1) ) And a plurality of sets of speaker units (3) arranged separately from each other at a plurality of positions for reproducing the signals recorded by the recorder (2),
The plurality of sets of speaker units (3) are arranged at the same position relative to the sound collection points (4) of the plurality of sets of microphone units (1),
The microphone unit (1) includes three or more sets of directional microphones (5) formed by directing the directivity directions radially in a horizontal plane,
The speaker unit (3) includes a plurality of speakers (6) that emit sound waves in the directivity direction of each microphone unit (1), and the direction in which each speaker (6) emits sound is the microphone (5 ) And the direction of the sound wave emitted from the speaker (6) is opposite to the direction of the sound wave picked up by the microphone (5). ,
The sound collected by each microphone (5) of the microphone unit (1) arranged at the plurality of sound collection points (4) is arranged at a position corresponding to the sound collection point (4) of the microphone (5). An acoustic space reproduction device configured to radiate from the speaker (6) of each speaker unit (3). It is equipped with two sets of microphone units (1) and two sets of speaker units (3) that are arranged apart from each other.
The acoustic space according to claim 1, wherein the two microphone units (1) are arranged so that the directivity direction is directed to one of the line segments connecting the sound pickup points (4) of the respective microphone units (1). Playback device.   The sound space reproducing device according to claim 1 or 2, wherein the microphone unit (1) includes three sets of directional microphones (5), and the speaker unit (3) includes three sets of speakers (6). .   The microphone unit (1) has a shielding plate (7) provided radially between adjacent microphones (5), and the microphone (5) is disposed between the shielding plates (7). An acoustic space reproduction device described in any of the above.   The acoustic space reproducing device according to any one of claims 1 to 4, wherein a listener who hears sound reproduced from the speaker unit (3) is a moving subject.

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