JPH03257497A - Acoustic reflecting and converging device - Google Patents

Abstract

PURPOSE:To utilize the device effectively for a conference, etc., by arranging a microphone which faces the internal surface of a 1st acoustic reflection body at or nearby a focus which is far away from the 1st acoustic reflection body and a speaker which faces a 2nd acoustic reflection body at or nearby a focus for the 2nd acoustic reflection body. CONSTITUTION:When a word is voiced at or nearby the focus F11, the voice which is reflected by the internal surface of the 1st acoustic semi-elliptic reflection body 1 is converged on the rear focus F12 without being diffused, so the microphone 5 arranged at the position collects the voice. A sound radiated by the speaker 6 is reflected by the internal surface of the 2nd acoustic reflection body 2 which is sectioned in a parabolic shape and propagated toward the 1st acoustic reflection body 1 almost in parallel to the major axis 2c of the reflection body 2, so the sound reaches both right and left ears of a person nearby the focus F11 equally, so there is no deviation in auditory feeling between the right and left ears. Further, the sound from the speaker 6 after being reflected by the internal surface of the 1st acoustic reflection body 1 is diffused more than the sound from the focus F11, so the energy reaching the microphone 5 is small and what is called howling is not caused.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is used, for example, in a conference using a television or a conference using a loudspeaker telephone, and includes a pair of acoustic reflectors and a microphone. The present invention relates to the structure of an acoustic reflection focusing device that uses a speaker and a speaker to realize efficient sound input and output.

[Problems to be solved by conventional technology and inventions] Recently, conference equipment using televisions and telephones has been used to allow people in two distant locations to exchange opinions, etc. It is being installed within the office.

In this case, if each person's voice is collected (input) with a microphone (telephone receiver) and heard through the earphone (receiver), the sound output from the earphone (receiver) can be heard through the microphone (transmitter). (speaker). However, when inputting voice using a transmitter, the transmitter must be held in the hand, making it difficult to write.

Furthermore, when people put earphones or headphones on their ears as a means of letting people hear audio, it is easy to feel uncomfortable or oppressed.

As a means to avoid such drawbacks, when the human input of audio is performed using a microphone and the audio output is performed using a speaker, the sound from this speaker enters the microphone again, is amplified, and is output from the speaker, resulting in a kind of buzzing phenomenon. Since there is a risk of so-called howling occurring, it is necessary to devise the installation positional relationship between the speaker and the microphone.

Furthermore, if you want people to hear the sound (voice, etc.) output from a speaker, the output of the speaker must be increased to a certain extent, so the sound from the speaker will reach far within a room, and the microphone If the microphone is placed away from people's mouths, the audio energy input into the microphone must be increased, and the voices emitted by the person will also be louder. get in the way.

In particular, in the case of a conference involving a large number of people, the audio energy is inevitably large, and the audio is likely to leak outside the conference area.

In order to eliminate this inconvenience, one of the inventors of the present application previously formed a pair of front and rear acoustic reflectors so that each section had a substantially semi-elliptic cylinder shape with the major axis divided into two, and The first acoustic reflector and the second acoustic reflector are arranged to face each other so that each focal point for each acoustic reflector (four focal points in total) is located in the inner diameter portion surrounded by the side acoustic reflector. death,
Of the two focal points for the first acoustic reflector, a microphone directed toward the inner surface of the first acoustic reflector is disposed at or near the focal point on the side far from the first acoustic reflector, and the second acoustic reflector It has been proposed to arrange a speaker directed toward the inner surface of the second acoustic reflector at or near the focus on the side closer to the second acoustic reflector among the two focal points for the reflector.

However, in the above invention, since the sound emitted from one of the pair of focal points and reflected on the inner surface of the acoustic reflector is concentrated at the other focal point, the microphone and speaker are placed at the focal point or There was a drawback that efficient sound collection or sound output could not be achieved unless it was placed in the vicinity.

Therefore, the inventor of the present application has completed the present invention by further developing the above-described technology. The purpose is to provide the following.

[Means to solve the problem]

In order to achieve this object, the invention as set forth in claim 1 provides a second acoustic reflector having a semi-cylindrical shape and having a substantially parabolic cross section, behind a first acoustic reflector having a substantially semi-elliptic cylindrical cross section with its major axis divided into two. The bodies are arranged so that their inner surfaces face each other and each focal point for each acoustic reflector is located at an inner diameter portion surrounded by the side acoustic reflector, and two
Of the two focal points, a microphone directed toward the inner surface of the first acoustic reflector is disposed at or near the focal point far from the first acoustic reflector, and a microphone directed toward the inner surface of the first acoustic reflector is disposed at or near the focus on the second acoustic reflector. is a device in which a speaker is disposed facing the inner surface of the second acoustic reflector, and the invention according to the second claim includes a speaker disposed at the rear of the first acoustic reflector having a semi-cylindrical shape with a substantially parabolic cross section, The second acoustic reflectors each having a substantially semi-elliptical cylindrical cross section with the major axis bisected are arranged with their inner surfaces facing each other, and each focal point of each acoustic reflector is located at an inner diameter portion surrounded by the side acoustic reflector. A microphone directed toward the inner surface of the first acoustic reflector is disposed at a position rearward of the focal point for the first acoustic reflector, and the microphone facing the inner surface of the first acoustic reflector is positioned behind the focal point for the second acoustic reflector. A speaker facing the inner surface of the second acoustic reflector is disposed at or near the focal point on the side closer to the second acoustic reflector.

[Action/effect of the invention]

In a first acoustic reflector having a substantially semi-elliptical cross section, the sound (human voice) emitted from the focal point closer to the inner surface of the first acoustic reflector or its vicinity among the two focal points for the acoustic reflector. is reflected from the inner surface of the acoustic reflector and converges at the focal point on the far side (closer to the inner surface of the other acoustic reflector),
Sound can be efficiently collected using a microphone placed at or near the focal point.

On the other hand, in the case of a second acoustic reflector having a parabolic cross section, if a speaker is placed at or near its focal point so as to face the inner surface of the second acoustic reflector, the sound emitted from the speaker will be transmitted to the second acoustic reflector.
After being reflected on the inner surface of the acoustic reflector, the sound propagates approximately parallel to the main axis of the parabola and becomes difficult to diffuse. The sound from the speakers can be heard evenly and well, and even if the position of the person is slightly shifted, the sense of hearing will not be disturbed.

Similarly, in the first acoustic reflector having a parabolic cross section in the second claim, if a person's mouth is placed at or near its focal point and sound is emitted toward the inner surface of the first acoustic reflector, the first acoustic The sound reflected from the inner surface of the reflector reaches the rear substantially parallel to the main axis and is difficult to diffuse.

Therefore, even if the position of the microphone arranged behind the first acoustic reflector so as to face the first acoustic reflector is deviated from the main axis of the parabola, the sound collection performance of the microphone will not deteriorate. .

On the other hand, of the two focal points for the second acoustic reflector having a substantially semi-elliptical cross section, the second acoustic reflector is arranged at or near the focal point closer to the inner surface of the second acoustic reflector; The sound from the speaker that outputs sound towards the
It is reflected from this inner surface and converges at a focal point on the side far from the second acoustic reflector, so even if the output of the speaker is small, it will not be heard by the ears of people who are located at or near the focal point.
The sound from the speaker can be heard clearly.

In this way, by arranging a person, a microphone, and a speaker in the above-mentioned arrangement on the inner diameter of a pair of acoustic reflectors, it is possible to efficiently collect sound by the microphone and to reduce the output of the speaker. You can hear it well even if it is made small.

Furthermore, since the first acoustic reflector and the second acoustic reflector are disposed so as to face each other front and back, it is difficult for the sound generated on the inner diameter side of the pair of acoustic reflectors to leak to the outside. This also eliminates the possibility that the contents of the meeting will leak outside or that noise will be spread outside the device of the present invention.

〔Example〕

Next, an example will be described. The first acoustic reflector 1 shown in FIGS. A second acoustic reflector 2 arranged as
are semi-cylindrical with a parabolic cross-sectional shape, and each cylinder axis extends in the vertical direction perpendicular to the floor surface 3 of the chamber.

The first acoustic reflector 1 and the second acoustic reflector 2 are made of metal plate members such as aluminum or iron plates, synthetic resin members, glass fibers, etc., each of which has a smooth surface that can reflect sound well on its inner side. It is molded from fiber-reinforced synthetic resin (FRP) containing carbon fiber, etc.

Moreover, these first and second acoustic reflectors 1. 2, vertically long and narrow plate-like members may be arranged with substantially no gaps so that the cross section becomes a semi-ellipse or a parabola.

The two focal points for the first acoustic reflector l having a substantially semielliptical cross section are F ll + F 12, and the second focal point having a substantially parabolic cross section is F ll + F 12.
One focal point for the acoustic reflector 2 is F. In this case, these three focal points are located at the inner diameter portion surrounded by the two acoustic reflectors 1.2.

Furthermore, the first acoustic reflectors 1 disposed opposite to each other
and the second acoustic reflector 2, so that a person can enter and exit from between the left and right sides or one side of both the acoustic reflectors, and a person is located in the inner diameter part with the person sitting on the seat part 4 such as a chair. Place them so that they are spaced apart from each other.

Of the two focal points for the first acoustic reflector 1, the focal point E''1 is closer to the inner surface of the first acoustic reflector 1.
At or near the first acoustic reflector 1, there is a mouth (voice part) of a person sitting or standing facing the inner surface of the first acoustic reflector 1.
2 relative to this first acoustic reflector 1.
A microphone 5 is placed at or near the far side of the two focal points F12 so as to face the inner surface of the first acoustic reflector l, so that the sound coming out of the person's mouth is transmitted to the first acoustic reflector l. The sound is reflected on the inner surface of the microphone 5 so that the sound can be efficiently collected by the microphone 5.

Also, a focal point F for the second acoustic reflector 2.

Alternatively, a speaker 6 is arranged near the second acoustic reflector so as to face the inner surface of the second acoustic reflector.

With this configuration, when a voice is uttered at or near the focal point F11, the sound reflected on the inner surface of the first acoustic reflector 1 will not be diffused and will be concentrated at the rear focal point F1□. Sound can be collected using microphone 5.

Further, the sound emitted from the speaker 6 is reflected by the inner surface of the second acoustic reflector 2, and the first acoustic reflector 1 is arranged approximately parallel to the upper axis 2C.
Since the sound is propagated in the direction, the sound evenly reaches both the left and right ears of a person located near the focal point 1''+1, and there is no difference in hearing between the left and right ears.

Furthermore, since the sound from the speaker 6 is reflected by the inner surface of the first acoustic reflector l, it is diffused compared to the sound from the focal point F, so less energy reaches the microphone 5, which prevents so-called howling. It never happens.

Note that even if the width between the left and right edges 2a and 2b of the second acoustic reflector 2 is made smaller than the width between the left and right edges 1a and 16 of the first acoustic reflector l, the second acoustic reflector 2 The amount of sound reflected from the speaker 6 on the inner surface does not decrease significantly.

FIG. 4 shows that among a pair of acoustic reflectors erected opposite each other from the floor surface 3, the first acoustic reflector 1' that faces a person is formed to have a substantially parabolic cross section and a linear semi-cylindrical shape. , is an embodiment in which the cross section of the second acoustic reflector 2' is formed into a substantially semielliptical cylinder shape, and in this case, the F 2 l of the two focal points with respect to the second acoustic reflector 2' is
+ F 2 The speaker 6 disposed at or near the focal point F21 on the side closer to the inner surface of the second acoustic reflector 2'
is disposed toward the inner surface of the second acoustic reflector 2', while the microphone 5 is disposed toward the inner surface of the first acoustic reflector 1' and at the focal point F of the first acoustic reflector 1'. It can be placed at any position further back.

In this way, the sound emitted from the mouth of a person at or near the focal point Fo of the first acoustic reflector 1' will be reflected on the inner surface of the first acoustic reflector 1', and will be aligned approximately parallel to its main axis IC. Since the signal is propagated backward, the microphone 5 does not need to be installed in a position that coincides with the main axis IC location.

Furthermore, since the sound from the speaker 6 is focused on the ears of the person at the other focal point F22, the content of the meeting can be easily heard even with a speaker with a low output.

In these embodiments, as shown in FIG. 3, a table 7 is provided on the inner surface of the first acoustic reflector 1, 1', and a microphone 5 is provided on the inner surface of the second acoustic reflector 2, 2'. It is preferable to provide a shelf board 8 that partitions the installation location of the speaker 6, and it is preferable that a sound absorbing material is provided on the surface of the shelf board 8 and the like on the side closer to the microphone 5. Also, microphone 5
It is preferable that the directivity characteristic is large in direction toward the inner surface of the first acoustic reflector and not directed toward the inner surface of the second acoustic reflector.

In addition, the acoustic reflectors that people face are equipped with TV CRs.
T (display device) 9 may also be provided.

Furthermore, an eaves portion may be provided at the upper end portion of the vertically elongated first acoustic reflector and/or second acoustic reflector to prevent sound from leaking from the inner diameter side to the outside.

In the embodiments shown in FIGS. 5 to 7, a pair of acoustic reflectors are arranged facing each other and are formed so that their cylindrical axes extend longitudinally from side to side in a manner substantially parallel to the floor surface 3. The first acoustic reflector 1 is a substantially semi-elliptic cylindrical body with a cross section divided into two, and the second acoustic reflector 2 is a semi-cylindrical body with a parabolic cross section. The length (Ll) is such that people can stand side by side at appropriate intervals.

In the embodiment shown in FIG. 6, the first acoustic reflector 1 is attached to and supported by a plurality of vertically adjustable stands 10 on the left and right that stand up from the floor surface 3, and the second acoustic reflector 2 is attached to the base 3. 1 unit
It is supported by a support 12 erected from 1.

The height between the upper and lower edges of the first acoustic reflector 1 may be approximately the same as that of the second acoustic reflector 2, or the height between the upper and lower edges of the second acoustic reflector 2 may be approximately the same as that of the second acoustic reflector 2. It may also be formed to be larger than the length.

Then, the first acoustic reflector 1 and the second acoustic reflector 2 are arranged to face each other, and the two focal points with respect to the first acoustic reflector 1 are F I l + F l 2, and the second acoustic reflector F focus on 2. In this case, these three focal points are arranged so as to enter the inner diameter portion surrounded by the two acoustic reflectors 1.2.

Furthermore, the first acoustic reflectors 1 disposed opposite to each other
and the second acoustic reflector 2, so that a person can enter and exit from between the left and right sides or one side of both the acoustic reflectors, and the person is located in the inner diameter part with the person sitting on the seat part 13 such as a chair. Place them so that they are spaced apart from each other.

Of the two focal points for the first acoustic reflector 1, the focal point F 1 is closer to the inner surface of the first acoustic reflector 1.
The mouth (speech part) of a person sitting or standing facing the inner surface of the first acoustic reflector 1 is located near the first acoustic reflector 1, and one of the two focal points for the first acoustic reflector 1 is At or near the far side focal point F2, a microphone 5 is arranged so as to face the inner surface of the first acoustic reflector l, so that the sound emitted from the opening of the hole is reflected on the inner surface of the first acoustic reflector l. so that the microphone 5 can collect the sound.

Also, a focal point F for the second acoustic reflector 2.

Alternatively, a speaker 6 is arranged near the second acoustic reflector so as to face the inner surface of the second acoustic reflector.

In this case, the microphone 5 and speaker 6 are connected to the base 1
The column 14.15 is attached to a column 14.15 erected from 1, but the column 14.15 is adjustable in front and back position and height (not shown) so that it can be easily aligned at or near each focal point F12+FQ position. It has a structure that can be moved or expanded.

Furthermore, as shown in FIG. 7, the number of seats is 13,
Further, the microphone 5 and speaker 6 are arranged behind each seat section 13, respectively.

With this configuration, the sound that comes out from one focal point of an ellipse and is reflected on the inner surface of the ellipse will gather at the other focal point, making it possible to utilize the property of the ellipse that the sound energy is difficult to diffuse. On the other hand, sound emitted from the focal point of an acoustic reflector with a parabolic cross section and reflected on its inner surface propagates outward (forward in the example) parallel to its principal axis, and is difficult to diffuse in other directions. properties can be used.

In other words, the focal point F II on the side closer to the inner surface of the first acoustic reflector
Sounds emitted from the vicinity can be efficiently collected by the microphone 5 located near the focal point F1° and facing in the direction of the first acoustic reflector. The sound emitted from the speaker 6 can be efficiently transmitted forward within a section of appropriate vertical width.

In this case, since the first acoustic reflector 1 has a horizontally elongated substantially semi-elliptical cylinder shape, the focal point for the first acoustic reflector 1 is an infinite number of points parallel to the cylindrical axis of the acoustic reflector], c. Therefore, the voice spoken toward the horizontally long first acoustic reflector 1 can be efficiently picked up by a microphone located at a focal position diagonally behind the person, other than the microphone 5 directly behind the person. Similarly, since the sound from the speaker 6 output toward the inner surface of the second horizontally long acoustic reflector 2 also reaches the ears of the person diagonally in front of the horizontal side, the number of microphones 5 and/or speakers 6 to be installed is as follows. Adjacent seat section 13
The number of seats may be smaller than the number of seats in question, and even if the person sitting on the seat part 13 moves slightly in the direction of the cylindrical axis of the first acoustic reflector 1, the sound will not be collected. There are no problems with sound or hearing.

Note that, as shown by the dashed line in FIG. It is desirable to provide only

By forming the first acoustic reflector 1 and the second acoustic reflector 2 in a horizontally long manner, a plurality of people can sit side by side in a conference device using this pair of acoustic reflectors, gather in one place, and have an efficient meeting. can proceed.

In addition, by increasing the height dimension (Hl) of the first acoustic reflector 1, the voice coming out of a person's mouth and the sound from the speaker can go around the edge of the first acoustic reflector 1 due to the sound diffraction effect. The phenomenon of forward leakage can be reduced.

In the embodiments shown in FIGS. 8 and 9, a second acoustic reflector 2 having an approximately parabolic cross section and a semi-cylindrical shape is disposed opposite to a first acoustic reflector l having a horizontally long approximately semi-elliptic cylinder shape. height dimension (H2) and length dimension (L2)), and a plurality of them are arranged, and the number corresponds to the number of seats for people located facing the first acoustic reflector 1. The second acoustic reflectors 2 are arranged at appropriate intervals (L3).

In this case, as shown by the solid line in FIG. 8, if each of the second acoustic reflectors 2 is arranged so that its cylindrical axis 2c is directed substantially horizontally, substantially the same effect as in the embodiment shown in FIG. 5 can be obtained. It can be effective.

Furthermore, each of the small second acoustic reflectors 2 is placed in a posture in which the cylinder axis 2c thereof is vertical (as shown by the dashed line in FIG. 8) and in a horizontal posture (as shown in the solid line in FIG. 8). It can also be configured so that its posture can be changed. In this case, each of the second acoustic reflectors 2 is attached to a rotating part 17 such as a drive motor provided on a support 12 erected from a base 11 as described above, so that the second acoustic reflector 2 can be rotated around the rotating part 17. You can also configure
The mounting may be configured to be detachable so that the posture can be changed.

In these embodiments as well, the microphone 5 and speaker 6 are installed at or near the focal point F l 21 FO, as in the embodiment shown in FIG. The number of acoustic reflectors 2 is equal to the number of acoustic reflectors 2, and they are provided at each location in front of the second acoustic reflector 2.

If each second acoustic reflector 2 is arranged so that the cylinder axis 2C is in the vertical direction as described above, the sound from the speaker 6 output toward the second acoustic reflector 2 will be The sound energy is focused parallel to the ears of the person in the front position, and the sound energy can be heard clearly at the ear points of the person in that position, but the amount of sound energy that reaches positions shifted laterally (left and right) is small. This makes it difficult for people sitting next to the person to hear the sound, so for example, at international conferences, multiple seats are set up on the left and right.
If you want each person to hear the content of the meeting with simultaneous interpretation in different languages, use the speakers 6 for each of the two second acoustic reflectors.
It is possible to output separate voices from each other, and in that case, they will not be confused with each other.

When the posture of the second acoustic reflector 2 is made horizontally long as described above, the sound from one speaker 6 can be heard almost simultaneously by multiple people located in front of it, and the second acoustic reflector 2 2 to the vertical orientation, the sound can be heard individually from each speaker 6. Therefore, if you switch any of the plurality of second acoustic reflectors 2 to the vertical orientation, and the others to the horizontal orientation. It is also possible to adopt a mode of use in which this is the case.

In the embodiment shown in FIG. 10, the horizontally long first acoustic reflector 1 shown in FIGS. 1
It is convenient for the person sitting in number 3 to take notes during the meeting. Also,
Since the top plate 19 of the table 18 blocks the lower part of the first acoustic reflector 1 from the floor surface 3, it is possible to reduce the sound that goes around the lower edge of the first acoustic reflector 1 and leaks to the outside. can.

Furthermore, if the small second acoustic reflector 2 shown in FIG. 8 is attached to the bookshelf-shaped cabinet 20 shown in FIG. At 21 locations on the panel (the upper and lower portions and left and right sides of the location where the second acoustic reflector 2 is arranged), the first
Acoustic reflector can block sound coming from the ground so that it does not leak backwards. In this case, if a sound-absorbing material is provided on the vertical panel 21, it is possible to prevent sound echoes and improve performance such as sound audibility (sound clarity, etc.).

Further, the second acoustic reflector 2 may be provided on one side of the cabinet 20 with the partitioning vertical panel 21 interposed therebetween, and a shelf section 22 for storing documents may be provided on the other side.

In addition, the second acoustic reflector 2 provided in the cabinet 20 may be configured to be able to rotate around the 17 rotating parts between a posture in which its cylinder axis is horizontal and a posture in which it is vertical (up and down). However, it goes without saying that the second acoustic reflector 2 may be repositioned on the upper and lower shelves so as to be detachable so that the height can be adjusted.

In the embodiment shown in FIG. 11, the first acoustic reflector l' located at the front facing the person is formed into a horizontally elongated semi-cylindrical body with a parabolic cross section, and the second acoustic reflector 2' located behind the person is formed. The focal point F of the first acoustic reflector l' when the cross section is formed into a substantially semi-elliptical cylindrical body. While placing the person's mouth at or near the position,
This focus F.

A microphone 5 is disposed further rearward toward the inner surface of the first acoustic reflector, and one of the two focal points of the second acoustic reflector 2' is
Focal point F21 on the side closer to the inner surface of the second acoustic reflector 2'
The speaker 6 is disposed facing the inner surface of the second acoustic reflector, and the length and height relationship and number combination of the first acoustic reflector and the second acoustic reflector are as follows: Said fifth
This embodiment is substantially the same as the embodiments shown in FIGS.

Also in the embodiment shown in FIG. 1, the first acoustic reflector 1
' can be provided on the table 18, and the second acoustic reflector 2' can be provided in the cabinet 20.
The effects are also substantially the same as in each of the above embodiments.

If the second acoustic reflectors are provided back to back on both the front and back sides of the vertical panels 21 of these cabinets 20, and the first acoustic reflectors with two tables are arranged facing each other on both the front and back sides of this cabinet 20, two pairs of acoustic reflectors can be provided. conference equipment can be configured all at once.

If a plurality of cabinets 20 each having a first acoustic reflector and a second acoustic reflector placed back to back are arranged at appropriate intervals,
This also allows a plurality of conference facilities to be formed.

Further, the first acoustic reflector 1 in each of the embodiments described above may be provided with a television CRT (display device) 9 that can be viewed by a person located on the inner surface thereof.

Furthermore, it goes without saying that it is equipped with a comprehensive amplifier associated with the microphone 5 and speaker 6, as well as transmitting and receiving equipment for television and audio. DDX network, 15DN network, etc. can be used.

Note that when the first acoustic reflector and the second acoustic reflector are viewed in side cross section, the major axis of the approximately semi-elliptical cylindrical acoustic reflector and the principal axis of the approximately parabolic cross-sectional acoustic reflector are defined by the height. They do not need to match in direction, and may be arranged in parallel with different heights, or may be arranged at an angle so as to intersect with each other at an appropriate angle when viewed from the side.
If the inclination angles of the acoustic reflector and the second acoustic reflector are configured to be adjustable, the speaker 6 can be adjusted according to the sitting height of the person sitting on the seat without changing the installation height of each acoustic reflector. Sound can be reflected efficiently and human voices can be efficiently picked up by the microphone 5.

Alternatively, the installation height of the second acoustic reflector placed behind the person may be lowered, and its major axis or main axis may be tilted upward in the direction of the first acoustic reflector 1. It is.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIG. 1 is a perspective view of a first acoustic reflector and a second acoustic reflector arranged vertically, and FIG. 2 is a cross section taken along the line II of FIG. 1. The cross-sectional view in Figure 3 is the In of Figure 2.
4 is a sectional view of an embodiment in which the first acoustic reflector is formed into a substantially parabolic cross section and the second acoustic reflector is formed into a substantially semielliptical cylindrical cross section; FIG. 6 is a side sectional view of the second embodiment, FIG. 7 is a cross-sectional view taken along the line ■-■ of FIG. 6, FIG. 8 is a perspective view of the third embodiment, and FIG. 9 is a plan sectional view. FIG. 10 is a sectional view of the fourth embodiment, and FIG. 11 is a sectional view of an embodiment in which the first acoustic reflector is formed to have a substantially parabolic cross section, and the second acoustic reflector is formed to have a substantially semi-elliptical cylindrical cross section. It is. 1.1'...First acoustic reflector, 2,2'...Second acoustic reflector, 3...Floor surface, 4,13...Seating section, 5...・Microphone, 6...Speaker, 7
...Table, 8...Shelf board, 9...CRT
, 10...stand, 11...base, 12,1
4.15... Support, 16... Partition plate, 17...
... Rotating part, 18 ... Table, 19 ... Top plate, 20 ... Cabinet, 21 ... Vertical panel,
22...Shelf section.

Claims (2)

[Claims] (1) Behind the first acoustic reflector, which has a substantially semi-elliptical cylindrical cross section with its major axis divided into two, a second semi-cylindrical acoustic reflector whose cross section is substantially parabolic, with their inner surfaces facing each other; and arranged so that each focal point for each acoustic reflector is located in an inner diameter portion surrounded by both of the acoustic reflectors, and of the two focal points for the first acoustic reflector, the one that is farthest from the first acoustic reflector. A microphone directed toward the inner surface of the first acoustic reflector is disposed at or near the focal point of the side, and a speaker directed toward the inner surface of the second acoustic reflector is disposed at or near the focal point of the second acoustic reflector. An acoustic reflection focusing device characterized by having: (2), behind the first semi-cylindrical acoustic reflector having a substantially parabolic cross section, a second acoustic reflector having a substantially semi-elliptic cylindrical cross section with its major axis divided into two, with their inner surfaces facing each other; The microphone is arranged so that each focal point for each of the acoustic reflectors is located at an inner diameter portion surrounded by both of the acoustic reflectors, and a microphone directed toward the inner surface of the first acoustic reflector is positioned at a focal point for each of the first acoustic reflectors. A speaker is disposed at a more rearward position, and at or near the focal point on the side closer to the second acoustic reflector among the two focal points for the second acoustic reflector, the speaker faces toward the inner surface of the second acoustic reflector. An acoustic reflection focusing device characterized by the following: