JP2007174271A - Sound emitting and collecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound emitting and collecting apparatus capable of improving an S/N ratio by suppressing sounds sneaking from a speaker to microphones while improving sound emitting characteristic. <P>SOLUTION: A reflection plate 13 is provided oppositely to a second surface 10B of a casing 1. The reflection plate 13 is formed into a shape in which the distance between the second surface 10B and the reflection surface of the reflection plate 13 gradually becomes longer from the center of the second surface 10B to its end. The sounds emitted from the speaker 3 provided on the second surface 10B propagate through a space to be formed by the second surface 10B and the reflection plate 13, and are radiated to the outside while using a direction perpendicular to a side surface 10C as a main propagation direction. The sneaking sounds to sneak to the first surface 10A side from the speaker 3 via the side surface 10C are already remarkably attenuated when propagating to the first surface 10A, and the propagation distance of the sneaking sounds is further prolonged while the sounds are collected by a plurality of microphones 2A-2H which are circularly arranged on the first surface 10A and in which the center direction of the circle is the direction of directivity. Thus, the sneaking sounds can be collected after being further attenuated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sound emission and collection device that is integrally provided with a speaker and a microphone, and more particularly to a sound emission and collection device in which a speaker and a microphone are provided on different surfaces of a housing.

As an audio communication system for conducting an audio conference (communication conference) in a remote place, an audio conference apparatus that is integrally provided with a speaker and a microphone is widely used. The audio conference apparatus transmits a collected signal collected by the microphone to the connection destination and emits an audio signal received from the connection destination from the speaker. When a conference is held among a plurality of people, such an audio conference apparatus is often installed at the center of a conference participant (the center of a conference desk or the like). As such an audio conference apparatus, Patent Document 1 proposes an apparatus in which a speaker is disposed on the surface of a rectangular parallelepiped housing having a low height and a plurality of microphones are provided on a side surface of the housing.
JP-A-8-298696

  Usually, in an audio conference, an audio conference device is placed on a desk, and a conference is performed such that a plurality of conference members surround the audio conference device. For this reason, in the audio conference apparatus having the configuration of Patent Document 1, the sound emission direction from the speaker is upward, and it is difficult for the conference person to hear. For this reason, a voice conferencing apparatus having a structure as shown in Patent Document 1 and having a predetermined leg on the surface side where the speaker is installed and the surface where the speaker is installed facing downward is also devised. ing. In the audio conferencing apparatus having such a configuration, sound emitted from the speaker is reflected by the lower surface of the casing and the top surface of the desk and propagates in the horizontal direction to convey the audio to the conference person.

  However, in the audio conference apparatus having such a structure, a standing wave is generated between the bottom surface of the housing including the speaker and the top surface of the desk, so that a high frequency component is attenuated and a specific frequency band is set in the conference. The problem that it becomes difficult to propagate to a person occurs.

  In addition, such an audio conference apparatus wraps around the microphone installed on the side surface when the sound emitted from the speaker is reflected between the bottom surface of the housing and the top surface of the desk and propagates in the horizontal direction. There is also a problem that sound is easily collected.

  Therefore, the present invention provides such a sound emitting and collecting apparatus including the downward speaker and the microphone disposed on a surface other than the speaker installation surface, and at the same time, improves the sound emission characteristics from the speaker and at the same time from the speaker to the microphone. The purpose is to suppress wraparound speech.

  A sound emission and collection device according to the present invention includes a housing having a first surface and a second surface facing each other, a microphone installed on the first surface side of the housing, and a substantially center on the second surface side of the housing. A speaker that is installed and has a sound emitting surface parallel to the second surface, emits sound from the second surface to the outside of the housing, and a reflector disposed at a predetermined distance from the second surface to the outside; The distance between the reflective surface of the plate and the second surface is gradually increased from the speaker placement position on the second surface to the end of the second surface.

  In this configuration, the sound emitted from the speaker is propagated through the space formed by the reflecting surface of the reflecting plate and the second surface of the housing. At this time, the vertical cross section of the space formed by the reflecting surface and the second surface has a horn shape that gradually spreads from the center of the second surface toward the end. Hereinafter, a space formed by the second surface of the casing and the reflecting surface of the reflecting plate is referred to as a “quasi-horn space”. Thereby, the sound emission propagating from the center side to the end side of the second surface of the housing is guided to the quasi-horn space and propagates to the end portion of the second surface, that is, the side surface of the housing. And it propagates from the side surface of the housing to the outside with the direction substantially perpendicular to the side surface side end surface of the quasi-horn space, that is, the substantially horizontal direction as the main propagation direction. Thereby, the wraparound sound in the direction parallel to the side surface is reduced.

  In addition, since the space near the center of the second surface among the spaces formed by the reflecting surface and the second surface is narrow, a standing wave due to the emitted sound is hardly generated, and the high-frequency component is hardly attenuated. As a result, sound having a frequency component distribution substantially equal to the original sound emitted from the speaker is propagated mainly from the side of the housing in the direction of the user (conference), and the sound emission characteristics for the user are improved. Furthermore, the amount of sneak sound from the side surface to the first surface is smaller than the amount of sneak sound from the second surface to the side surface. The sneak sound produced is further reduced.

  The reflector of the sound emission and collection device of the present invention is characterized in that it has a shape that gradually rises from the side with respect to the end of the second surface to the side with respect to the speaker arrangement position of the second surface toward the second surface. .

  In this configuration, the distance between the reflecting surface and the second surface gradually decreases from the position with respect to the end of the second surface to the position with respect to the speaker arrangement position on the second surface, and the quasi-horn space is formed.

  Further, the microphone of the sound emission and collection device of the present invention is arranged substantially symmetrically on the first surface with point symmetry with respect to the center of the circle, and each directs a directivity axis toward the center of the circle. The center of the circle formed by the plurality of unidirectional microphones and the center of the speaker are located on the same vertical line with respect to the first surface and the second surface. It is characterized by doing.

  In this configuration, the wraparound sound that wraps around from the side surface to the first surface side is not picked up by the microphone installed at the closest position from the wraparound side surface position, but is picked up by the microphone installed at the farthest position. The Thereby, during the first surface propagation, the wraparound sound is further attenuated, and the sound collecting intensity of the wraparound sound by the microphone is further suppressed.

  The sound emission and collection device of the present invention includes a housing having a first surface and a second surface facing each other, a microphone installed on the first surface side of the housing, and an abbreviation on the second surface side of the housing. A plurality of speakers installed circumferentially with respect to the center and emitting sound from the second surface to the outside of the housing; and a reflector disposed at a predetermined distance from the second surface to the outside; The distance between the reflecting surface and the second surface is gradually increased from the speaker placement position on the second surface to the end of the second surface.

  In this configuration, sound simultaneously emitted from each speaker is propagated through a space formed by the reflecting surface of the reflecting plate and the second surface of the housing. At this time, the space formed by the reflecting surface and the second surface is the quasi-horn space described above. As a result, the sound emitted from each speaker position on the second surface of the housing to the end portion close to each speaker is guided to this quasi-horn space, that is, the end portion of the second surface, that is, the side surface of the housing. Is propagated to. And it propagates from the side surface of the housing to the outside with the direction substantially perpendicular to the side surface side end surface of the quasi-horn space, that is, the substantially horizontal direction as the main propagation direction. Thereby, the wraparound sound in the direction parallel to the side surface is reduced.

  In addition, among the spaces formed by the reflecting surface and the second surface, the space near the center of the second surface is narrow, so that standing waves due to sound emitted from each speaker hardly occur, and high-frequency components are not generated. Almost no attenuation. As a result, sound having a frequency component distribution substantially equal to the original sound emitted from the speaker is propagated mainly from the side of the housing in the direction of the user (conference), and the sound emission characteristics for the user are improved. Furthermore, the amount of sneak sound from the side surface to the first surface is smaller than the amount of sneak sound from the second surface to the side surface. The sneak sound produced is further reduced.

  The reflector of the sound emission and collection device of the present invention is characterized in that it has a shape that gradually rises toward the second surface from the side with respect to the end of the second surface to the side with respect to the center of the circle formed by the plurality of speakers. .

  In this configuration, the distance between the reflecting surface and the second surface gradually decreases from the position relative to the end of the second surface to the position relative to the center of the circle formed by the plurality of speakers on the second surface, thereby forming a quasi-horn space.

  The reflector of the sound emission and collection device of the present invention is in contact with the second surface at the center side of a circle formed by a plurality of speakers, and the distance between the reflecting surface and the second surface is from the speaker placement position on the second surface. It is characterized by being formed in a shape that becomes gradually longer toward the end of the second surface.

  In this configuration, since there is no space for sound emission to enter the center side of a circle by a plurality of speakers, the sound emission sound is effectively propagated to the end portion side of the second surface. Further, since there is no space at the center of the second surface, no standing wave is generated and the high-frequency component of the emitted sound is not attenuated. As a result, sound having the same frequency component distribution as the original sound at the time of sound emission is further propagated to the user via the side of the casing.

  Further, the microphone of the sound emission and collection device of the present invention is arranged substantially symmetrically on the first surface with point symmetry with respect to the center of the circle, and each directs a directivity axis toward the center of the circle. The center of the circle formed by the plurality of unidirectional microphones and the center of the circle formed by the plurality of speakers are relative to the first surface and the second surface. It is characterized by being located on the same vertical line.

  In this configuration, even when a plurality of speakers are arranged on the second surface side, the wraparound sound that wraps around from the side surface to the first surface side is picked up by the microphone installed at the farthest position from the wraparound side surface position. The Thereby, during the first surface propagation, the wraparound sound is further attenuated, and the sound collecting intensity of the wraparound sound by the microphone is further suppressed.

  In addition, the second surface of the sound emitting and collecting apparatus of the present invention is characterized in that the distance between the second surface and the first surface is formed so as to gradually shorten from the center to the end.

  In this configuration, the above-described quasi-horn space can be realized even if the reflecting plate has a flat plate shape.

  In the sound emission and collection device of the present invention, the support part that separates the second surface and the reflection plate by a predetermined distance is formed by a mesh-like member that is disposed along the second surface and the end of the reflection plate. It is characterized by.

  In this configuration, since the support portion that supports the reflecting plate is a mesh member, the sound emitted from the speaker is propagated in the direction perpendicular to the side surface of the casing, that is, in all horizontal directions. Is output to the outside.

  According to the present invention, the reflective surface of the reflector and the second surface of the housing are formed from the center of the second surface of the housing where the single speaker or the plurality of speakers are installed to the end of the second surface. Since the vertical space is formed in a horn shape, the sound emitted from the speaker can be propagated from the side surface of the housing to the user as the original sound. Furthermore, by installing the microphone on the second surface having the speaker and the first surface on the opposite side through the housing, the propagation path of the wraparound sound, that is, the echo path becomes longer, and the sound that wraps around the microphone from the speaker is suppressed. / N ratio can be improved.

A sound emission and collection device according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a main part of a sound emission and collection device 100 of the present embodiment, and (A) is a plan view. In FIG. 1A, the right side toward the paper surface is the + X direction, the left side toward the paper surface is the -X direction, the upper side toward the paper surface is the + Y direction, and the lower side toward the paper surface is the -Y direction. . 1B is a side view seen from the −Y direction, FIG. 1C is a cross-sectional view taken along the line AA ′ in FIG. 1A, and FIG. 1D is a side view seen from the + X direction.
FIG. 2 is a diagram illustrating the distance between the second surface 10 </ b> B of the housing 1 and the reflecting surface of the reflecting plate 13.

  The sound emitting and collecting apparatus 100 according to the present embodiment includes a housing 1, a plurality of microphones 2A to 2H, a speaker 3, a support member 4, a reflecting plate 13, and a signal processing function unit described later.

  The casing 1 has a substantially cylindrical outer shape, and has a first surface 10A and a second surface 10B that are substantially the same size and are flat, and are circular at the end portions of the first surface 10A and the second surface 10B. It has a circumferential side surface 10C that connects and arranges them at predetermined intervals.

  The second surface 10B of the housing 1 has a relationship in which the second surface 10B and the sound emitting surface substantially coincide with each other, and the sound emitting direction is from the second surface 10B to the external direction of the housing 1. A speaker 3 is arranged. Furthermore, the speaker 3 is disposed at a position where the center of the directivity axis of the speaker 3 coincides with the center of the second surface 10B. And as the speaker 3, it is comprised by the non-directional speaker which consists of a cone-type speaker unit etc. Thereby, the sound emitted from the speaker 3 is output with the center of the second surface 10B being the center of the sound emitting surface.

  In addition, four support members 4, each of which is disposed at an interval of approximately 90 degrees, are installed at the end of the second surface 10 </ b> B, and by this support member 4, substantially the same planar shape as the second surface 10 </ b> B. The reflecting plate 13 is installed facing the second surface 10B. Note that the number and arrangement position of the support members 4 can be appropriately set according to specifications.

As shown in FIG. 2, the reflecting plate 13 has a disk shape in which the center portion is curved with respect to the end portion and rises toward the second surface 10B, and the distance D1 between the reflecting surface and the second surface 10B at the center is set. It is the shortest, and is formed in a shape in which the distance between the reflecting surface and the second surface 10B gradually increases from the center to the end.
Specifically, in the example of FIG. 2, from the center to the end of the reflector 13 and the second surface 10B,
Distance D1 <distance D2 <distance D3 <distance D4 which is the distance at the end, which is the distance at the center,
It becomes.

  With such a structure, the space surrounded by the reflecting surface of the reflecting plate 13 and the second surface 10B is formed in a shape in which the vertical cross-sectional shape is a horn shape, that is, the quasi-horn space described above is formed. Is done. Thereby, the sound emitted from the speaker 3 is propagated through the quasi-horn space and guided to the side surface 10 </ b> C of the housing 1. At this time, the sound emission is propagated equally in the direction perpendicular to the side surface 10C, that is, in all directions in the horizontal direction.

  Since the opening on the second surface 10B side along the side surface 10C is an opening surface of the quasi-horn space, sound emission is mainly radiated in a direction perpendicular to the opening surface. Thereby, the sound emitted from the side surface 10C of the housing 1 is propagated mainly in the horizontal direction perpendicular to the side surface 10C and is heard by the user in this direction. On the other hand, since the sound emission signal propagates and radiates in this way, it is possible to reduce the wraparound sound that wraps around from the second surface 10B to the side surface 10C.

  Further, the distance between the second surface 10B and the reflecting surface of the reflecting plate 13 at the center of the second surface 10B and the reflecting plate 13 is short, and the second surface 10B and the end of the reflecting plate 13 (portion corresponding to the side surface 10C). The distance between the second surface 10B and the reflecting surface of the reflecting plate 13 is long. For this reason, since the space surrounded by the second surface 10B and the reflecting plate 13 is a direction that diverges from the center toward the end portion, a closed space is not formed near the center and no standing wave is generated. Thereby, the high frequency component of the emitted sound is not attenuated, and the sound radiated to the outside from the side surface 10 </ b> C has a frequency component that is not different from the emitted sound from the speaker 3. That is, the original sound emitted from the speaker 3 is propagated to the user.

  The cross-sectional shape of the reflecting plate 13 may be a structure in which the distance D increases nonlinearly from the center to the end as shown in FIG. 2, or a structure in which the distance D increases linearly. In the case of non-linearity, the shape can be set relatively easily by using a shape derived from a part of a simple non-linear function such as a quadratic function or a cycloid curve. Further, the shape of the reflector 13 may be set using the result of simulating the sound emission signal radiated from the side surface 10C to the outside for each of various shapes.

  A concave portion 11 having a circular planar shape is formed on the first surface 10A of the housing 1, and a circular center when the first surface 10A is viewed in plan and a circular center when the concave portion 11 is viewed in plan match. To do. This center point is hereinafter referred to as “center point O”. The center point O and the centers of the second surface 10B, the sound emitting surface, and the reflecting plate 13 are the first surface 10A and the second surface 10B. It is arranged so as to be located on the same vertical line perpendicular to

  The microphones 2 </ b> A to 2 </ b> H are unidirectional microphones and are arranged at point-symmetric positions with the center point O as a reference point. Further, each of the microphones 2A to 2H is installed at a predetermined distance or more from the center point O, and more preferably is installed at a position near the edge portion of the first surface 10A.

  Specifically, as shown in FIG. 1A, the microphones 2A to 2H are respectively set along the inner wall surface 12 that is the same distance from the center point O and the microphone 2A is + X with the center point O as a reference point. The microphone 2E is arranged in the −X direction. Similarly, with the center point O as a reference point, the microphone 2B is arranged in a 45 degree direction in the + X direction and the + Y direction, and the microphone 2F is arranged in a 45 degree direction in the −X direction and the −Y direction. With the center point O as a reference point, the microphone 2C is arranged in the + Y direction, and the microphone 2G is arranged in the -Y direction. Further, with the center point O as a reference point, the microphone 2D is arranged in a 45 degree direction in the −X direction and the + Y direction, and the microphone 2H is arranged in a 45 degree direction in the + X direction and the −Y direction.

  Each of the microphones 2 </ b> A to 2 </ b> H is installed such that the direction of directivity is the direction toward the center point O. Thereby, each microphone 2A-2H is set so that the sound collection sensitivity in the direction of the center point O is higher than the sound collection sensitivity in the other direction. That is, each of the microphones 2A to 2H mainly collects sound from the farthest side surface direction.

  In this way, by installing the microphones 2A to 2H on the first surface 10A on the opposite side via the second surface 10B and the housing 1, the wraparound sound to the side surface 10C as described above is further reduced to the first surface. Since the sound is not collected unless it wraps around 10A, the sneak sound collected is small. Further, by setting the directivity direction of each of the microphones 2A to 2H as the center point O as described above, the sneak sound sneak into the first surface 10A from the side surface 10C is collected by the microphone closest to the sneak position. Instead, sound is picked up by the microphone farthest from the wraparound position. As a result, each of the microphones 2A to 2H collects the wraparound sound with the longest propagation path, so that the collected wraparound sound is further attenuated, and the sound collection intensity of the wraparound sound is further suppressed. .

  Although not shown in FIG. 1, a signal processing function unit to be described later is installed in an empty space other than the arrangement positions of the microphones 2 </ b> A to 2 </ b> H and the speaker 3 in the housing 1. The input / output connector 26 is installed, for example, on the side surface 10C of the housing 1 (not shown).

  Such a sound emitting and collecting apparatus 100 is arranged and used as shown in FIG.

  FIG. 3 is a diagram illustrating a case where two users 201 and 202 use the sound emitting and collecting apparatus 100 of the present embodiment, where (A) is a plan view and (B) is a side view. 3A and 3B, the right side toward the paper surface is the + X direction, and the left side toward the paper surface is the -X direction. In FIG. 3A, the upper side toward the paper surface is the + Y direction, and the lower side toward the paper surface is the -Y direction. In FIG. 3B, the upper side toward the paper surface is the + Z direction, and the lower side toward the paper surface is the -Z direction.

  The sound emission and collection device 100 is disposed on the top surface at a substantially central position of the top surface of the desk 200. At this time, the reflector 13 is placed in contact with the top surface of the desk 200.

  Although not shown, the sound emitting and collecting apparatus 100 is connected to the LAN via the input / output connector 26 described above, and is separated from a remote location, for example, a completely different place from the room where the apparatus is installed. , Connected to another sound emitting and collecting device arranged in.

  Users 201 and 202 face each other on opposite sides of the desk 200 on which the sound emitting and collecting apparatus 100 is disposed. In the example of FIG. 3, the user 201 is in the −X direction with respect to the sound emitting and collecting apparatus 100, and the user 202 is in the + X direction with respect to the sound emitting and collecting apparatus 100.

(1) Voice from a partner in a separate room When these users 201 and 202 hear a voice from a partner user in a room of another sound emitting and collecting device, they are output from the speaker 3 of the sound emitting and collecting device 100, and the quasi-horn You will hear the sound propagated through the space and emitted to the outside.

  Specifically, when the speaker 3 emits the uttered sound of the other user, the speaker 3 is circumferentially formed in the horizontal direction by the quasi-horn space formed by the second surface 10B of the housing 1 and the reflecting surface of the reflecting plate 13. The sound is propagated while being diffused and emitted in a direction perpendicular to the side surface 10C, that is, in the horizontal direction. This sound is mainly propagated to the users 201 and 202 who are enrolled around the sound emitting and collecting apparatus 100. At this time, the sound emitted from the side surface 10C maintains the same frequency component as that of the original sound emitted by the speaker 3 as described above, and the user 201 and 202 are partially composed of high frequency components. The voice of the other user can be propagated to the users 201 and 202 without making the user feel the lack of frequency components.

  A very small part of the sound emission sound 300 is propagated to the first surface 10A side of the housing 1 through the side surface 10C of the housing 1, but as described above, it is almost stored in the microphones 2A to 2H. There is no sound.

(2) Voices from the users 201 and 202 These users 201 and 202 speak to the sound emitting and collecting apparatus 100 when talking to the other user in the room of another sound emitting and collecting apparatus.

  When the user 201 utters, the uttered sound 301 reaches the microphones 2A to 2H of the sound emitting and collecting apparatus 100 while diffusing and attenuating. Here, as described above, the microphone 2A has a directivity having high sound collection sensitivity in the direction of the center point O of the housing 1, that is, in the −X direction where the user 201 exists, with respect to the microphone 2A. . Therefore, the microphone 2A is present at a position farthest from the user 201 as compared with the other microphones 2B to 2H, but can utter the uttered sound 301 with high sensitivity. On the other hand, the microphone 2E that is point-symmetric with the microphone 2A is present at a position closest to the user 201 as compared to the other microphones 2A to 2D and 2F to 2H. However, since the microphone 2E has high sound collection sensitivity in the + X direction and directivity having almost no sound collection sensitivity is set in the -X direction, the utterance sound 301 is hardly collected.

  When the user 202 utters, the uttered sound 302 reaches the microphones 2 </ b> A to 2 </ b> H of the sound emitting and collecting apparatus 100 while being diffused and attenuated. Here, as described above, the microphone 2E is set to have directivity having high sound collection sensitivity in the direction of the center point O of the housing 1, that is, in the + X direction where the user 202 exists, with respect to the microphone 2E. Therefore, the microphone 2E is present at a position farthest from the user 202 as compared with the other microphones 2A to 2D and 2F to 2H, but can utter the uttered sound 302 with high sensitivity. On the other hand, the microphone 2A that is point-symmetric with the microphone 2E is located closest to the user 202 as compared to the other microphones 2B to 2H. However, since the microphone 2A has high sound collection sensitivity in the −X direction and directivity having almost no sound collection sensitivity is set in the + X direction, the microphone 2A hardly collects the uttered sound 302.

  Thus, the user's uttered sound is mainly collected by the microphone disposed at the opposite position extending from the side surface where the user is located through the center point O.

  As described above, by using the configuration of the present embodiment, the uttered sound from the other user can be propagated to the user while maintaining the original sound, and the sneak sound from the speaker to the microphone can be suppressed. it can.

  In addition, by using the configuration of the present embodiment, a voice utterance from the user, which is a necessary voice, is collected with high sensitivity, and a voice that wraps around from the speaker to the microphone is greatly attenuated while keeping the housing small. be able to.

  As a result, high sound reproducibility and high S / N ratio can be realized simultaneously.

  In the above description, the second surface 10B is formed in a flat shape, and the example in which the shape of the reflecting plate 13 is formed in a disk shape whose center rises toward the second surface 10B is shown. ) And (B).

  FIG. 4 is a side view showing another configuration of the sound emission and collection device of the present embodiment. In addition, the same code | symbol is attached | subjected to the same part as the sound emission and collection apparatus 100 shown in FIG.

  In the sound emission and collection device 101 shown in FIG. 4A, the reflecting plate 14 is formed in a flat plate shape, and the second surface 10B of the housing 1B is formed from the center of the second surface 10B and the first surface 10A. The second surface 10 </ b> B and the first surface 10 </ b> A are formed in a shape having a curved surface 15 such that the distance gradually decreases toward the end portion in contact with the side surface 10 </ b> C. The curved surface 15 gradually increases the distance between the second surface 10B and the reflecting surface of the reflecting plate 14 from the center to the end of the second surface 10B and the reflecting surface 14, thereby forming the quasi-horn space as described above. The Even with such a configuration, the above-described actions and effects can be achieved.

  Further, in the sound emission and collection device 102 shown in FIG. 4B, the above-described curved reflecting plate 13 and the second surface 10B including the curved surface 15 shown in FIG. 4A are combined. In such a configuration, as compared with FIG. 1 and FIG. 4A, if the outer dimensions of the sound emitting and collecting apparatus are constant, the second surface 10B and the reflecting plate 13 between the center and the end. Further, a more ideal horn shape can be formed, and further, free shape design can be performed on the two opposing surfaces, and the design freedom of the horn shape is improved. Note that the design for the shape of the curved portion in the sound emission and collection devices 101 and 102 shown in FIGS. 4A and 4B can also be set as appropriate as described above.

  Next, a sound emission and collection device according to the second embodiment will be described with reference to FIG.

5A and 5B are diagrams showing a configuration of a main part of the sound emitting and collecting apparatus 103 including a plurality of speakers, where FIG. 5A is a plan view, FIG. 5B is a side view seen from the −Y direction, and FIG. AA 'sectional drawing in A), (D) is the side view seen from + X direction. 5A, the right side toward the paper surface is the + X direction, the left side toward the paper surface is the -X direction, the upper side toward the paper surface is the + Y direction, and the lower side toward the paper surface is the -Y direction. . The same parts as those of the sound emitting and collecting apparatus 100 shown in FIG.
The sound emitting and collecting apparatus 103 shown in FIG. 5 has a plurality of speakers 3A to 3D installed on the second surface 10B, and each speaker 3A to 3D is spaced 90 degrees from the center of the second surface 10B. It is arranged in point symmetry. The reference points for the arrangement of the speakers 3A to 3D are located on the same vertical line with respect to the first surface 10A and the second surface 10B together with the center point O for the arrangement of the microphones 2A to 2H.

  Specifically, as shown in FIG. 5A, the speakers 3A to 3D are arranged at the same distance from the reference point, the speaker 3A is arranged in the + X direction, and the speaker 3C is arranged in the −X direction. By doing so, it becomes point-symmetric with respect to the reference point. Similarly, the speaker 3B is arranged in the + Y direction and the speaker 3D is arranged in the −Y direction, so that the speaker 3B is point-symmetric with respect to the reference point.

The reflecting plate 15 has a disk shape with its center portion curved toward the second surface 10B while being curved with respect to the end portion, and at the center side of the position where the speakers 3A to 3D are arranged on the second surface 10B. It is in contact with the surface 10B. In this configuration, the distance between the reflecting surface and the second surface 10B at the center is “0”, and the distance between the reflecting surface and the second surface 10B at the positions where the speakers 3A to 3D are arranged is the shortest, and the end portion from here The distance between the reflection surface and the second surface 10B is gradually increased.
With such a configuration, there is no space in the center and no standing wave of sound emission is generated. Thereby, the high frequency component of the emitted sound is not attenuated, and the emitted sound from the speakers 3A to 3D can be propagated to the user with the frequency component distribution as it is.

In the present embodiment, the example in which the reflecting plate 15 is brought into contact with the second surface 10B has been described. However, as shown in FIG. Further, the number of speakers is not limited to four and may be set as appropriate.
Further, the configuration of the curved surface 15 of the second surface 10B shown in FIG. 4 may be applied to the configuration of FIG.

  By the way, in each above-mentioned embodiment, although the supporting member 4 was made into the cylinder, as shown in FIG. 6, you may make it the curved plate 41 by which mesh-like punching was performed. The curved plate 41 may be formed integrally with the reflecting plate 13 or may be formed separately.

  FIG. 6 is a diagram showing a main configuration of the sound emission and collection device 104 using the mesh curved plate 41 as a support member, and the same parts as those in FIG.

  By adopting such a configuration, the sound emitted from the speaker 3 and propagated through the quasi-horn space is not partially disturbed by the support member at the position of the side surface 10C, and is equivalent to all directions. It is possible to propagate sound emission.

  Further, in the present embodiment, the short cylindrical housing 1 has been described as an example, but may be an elliptic cylinder shape with a planar cross section being an ellipse, and may be a rectangular parallelepiped shape.

  Moreover, in this embodiment, although the example which arrange | positions the 2nd surface 10B side which has the speaker 3 facing the 1st surface of the desk 200 was shown, the 2nd surface 10B side which has the speaker 3 is a room where a user exists. You may arrange | position so that the reflectors 13, 14, and 15 may be connected to a ceiling surface toward the ceiling.

  Further, in this embodiment, the case where there are eight microphones and one speaker is shown. However, as described above, the microphone and the speaker are arranged on the opposite surfaces of the housing, and the microphone directivity as described above. Is set, the number of microphones and the number of speakers can be set as appropriate.

  Next, a signal processing function unit that processes the collected sound signal collected as described above will be described.

FIG. 7 is a block diagram showing the configuration of the sound emission and collection device of the present embodiment.
The sound emission and collection device of the present embodiment includes the input / output connector 26 in addition to the microphones 2A to 2H and the speaker 3 described above, and further includes input amplifiers 21A to 21H and an A / D converter as signal processing function units. 22A to 22H, a microphone signal processing circuit 23, an echo canceller 24, an input / output interface 25, a D / A converter 31, and an output amplifier 32.

  The input / output interface 25 gives the input audio signal input from the input / output connector 26 to the D / A converter 31 via the echo canceller 24. The D / A converter 31 converts the input audio signal into an analog signal and supplies it to the output amplifier 32, and the output amplifier 32 amplifies the input audio signal and outputs it to the speaker 3. The speaker 3 converts the input sound signal into sound and emits the sound.

  Each of the microphones 2A to 2H collects sound from the outside, converts it into a sound collection signal, and outputs it to the input amplifiers 21A to 21H. Each of the input amplifiers 21A to 21H amplifies the collected sound signal and outputs it to the A / D converters 22A to 22H. The A / D converters 22 </ b> A to 22 </ b> H digitally convert each collected sound signal and output it to the microphone signal processing circuit 23. Hereinafter, the collected sound signals collected by the microphones 2A to 2H and output from the A / D converters 22A to 22H are simply referred to as signals A to H, respectively.

FIG. 8 is a detailed block diagram of the microphone signal processing circuit 23.
The microphone signal processing circuit 23 includes adders (subtractors) 231A to 231H, a select / mixing circuit 232, and a maximum signal strength detection circuit 233.

  The adder 231A receives the signal A output from the A / D converter 22A and the signal E output from the A / D converter 22E. The adder 231A subtracts the signal E from the signal A and outputs a correction signal A. Here, the signal A is a sound collected signal by the microphone 2A, and the signal E is a sound collected signal by the microphone 2E. As described above, since the microphone 2A and the microphone 2E are arranged at point-symmetric positions with respect to the center point O, the wraparound sound collected by each is substantially the same. Thus, by subtracting the signal E from the signal A, this wraparound audio component can be reduced.

  Similarly, the correction signal B is generated by subtracting the signal F from the signal B by the adder 231B, the correction signal C is generated by subtracting the signal G from the signal C by the adder 231C, and the correction signal D is added. The signal 231D is generated by subtracting the signal H from the signal D.

  The adder 231E receives the signal E output from the A / D converter 22E and the signal A output from the A / D converter 22A. The adder 231E subtracts the signal A from the signal E and outputs a correction signal E. Similarly, the correction signal F is generated by subtracting the signal B from the signal F by the adder 231F, the correction signal G is generated by subtracting the signal C from the signal G by the adder 231G, and the correction signal H is added. The signal 231H is generated by subtracting the signal D from the signal H.

  As a result, the correction signal A to the correction signal H can each reduce the wraparound sound component.

  The generated correction signals A to H are input to the select / mixing circuit 232 and the maximum signal strength detection circuit 233. The maximum signal strength detection circuit 233 compares the signal strengths of the correction signals A to H, that is, the sound pressure level, selects the correction signal with the highest signal strength, and selects the correction signal with the highest signal strength. Is supplied to the select / mixing circuit 232. The select / mixing circuit 232 selects a corresponding correction signal from the input correction signals A to H based on the selection information given from the maximum signal intensity detection circuit 233 and outputs the selected correction signal to the echo canceller 24. The maximum signal strength detection circuit 233 detects the correction signal with the highest signal strength, selects the correction signal with the maximum signal strength and a plurality of correction signals adjacent to the correction signal, and selects / mixes the selection signal. 232 may be given. Furthermore, in view of the case where there are a plurality of sound sources in different directions, a plurality of correction signals may be selected in order from the correction signal with the highest signal intensity and provided to the select / mixing circuit 232. In these cases, the select / mixing circuit 232 selects a plurality of corresponding correction signals based on the selection information, mixes them, and outputs them to the echo canceller 24.

  By performing such a selection process, a correction signal having a low signal strength, which is unlikely to be a voice uttered by the user, is deleted, so that the S / N ratio can be further improved.

FIG. 9 is a detailed block diagram of the echo canceller 24.
The echo canceller 24 includes an adaptive filter 241 and an adder 242. The adaptive filter 241 includes a digital filter such as an FIR filter, estimates the transfer function of the acoustic propagation path from the speaker 3 to the microphones 2A to 2H, and filters the filter coefficient of the FIR filter so as to simulate the estimated transfer function. Is calculated. The adaptive filter 241 generates a pseudo regression sound signal using the estimated filter coefficient and outputs the pseudo regression sound signal to the adder 242. The adder 242 subtracts the pseudo regression sound signal from the output signal of the microphone signal processing circuit 23 and outputs the result to the input / output interface 25 as an output audio signal. Here, the estimation of the transfer function and the calculation of the filter coefficient are performed based on the input audio signal supplied to the speaker 3 by feeding back the residual signal, which is the signal output from the adder 242, as a reference signal to the adaptive filter 241. Iteratively using an adaptive algorithm. Thereby, the estimation of the transfer function and the setting of the filter coefficient are optimized.

  By performing such processing, the wraparound audio component is further suppressed, and the S / N ratio of the audio signal output to the input / output interface 25 is further improved.

  As described above, in the sound emission and collection device of the present embodiment, the wraparound sound can be mechanically reduced by making the positional relationship between the speaker and the microphone as described above. In addition, by setting the microphone installation pattern as described above, it is possible to effectively suppress the sneak sound component included in the collected sound signal of each microphone, and further, by performing echo canceling, the sneak sound component Can be further suppressed. Thereby, a very excellent S / N ratio can be realized for the output audio signal.

Further, the configuration of the microphone signal processing circuit 23 is not limited to the above example.
FIG. 10 is a block diagram showing another configuration of the microphone signal processing circuit 23. The microphone signal processing circuit 23 shown in FIG. 10 differs from the microphone signal processing circuit 23 shown in FIG. 8 only in the signal synthesis portion.
The adder 231A receives the signal A output from the A / D converter 22A and the signal B output from the A / D converter 22B. The adder 231A adds the signal A and the signal B and outputs the result. Similarly, the adder 231B adds and outputs the signal B and the signal C, the adder 231C adds and outputs the signal C and the signal D, and the adder 231D adds the signal D and the signal E. Output. The adder 231E adds and outputs the signal E and the signal F, the adder 231F adds and outputs the signal F and the signal G, and the adder 231G adds the signal G and the signal H. The adder 231H adds the signal H and the signal A and outputs the result. As described above, the microphone signal processing circuit 23 shown in FIG. 8 adds and outputs the collected sound signals obtained from two adjacent microphones. In this way, by adding the collected sound signals of adjacent microphones, the collected sound signal component from the front direction of the microphone, that is, the direction in which high sound collection sensitivity is set, is strengthened, and the collected sound signal from other directions Ingredients are weakened. Thereby, a signal with higher directivity can be obtained.

Further, the configuration of the microphone signal processing circuit 23 may be as follows.
FIG. 11 is a block diagram of a signal synthesis unit in another microphone signal processing circuit 23.
The microphone signal processing circuit 23 shown in FIG. 11 is also different from the microphone signal processing circuit 23 shown in FIG.
The microphone signal processing circuit 23 shown in FIG. 11 includes adders 237A to 237H, delay circuits 234A to 234H, 235A to 235H, and 236A to 236H. Signals A to H are input to delay circuits 234A to 234H, 235A to 235H, and 236A to 236H, respectively. For example, the signal A is input to the delay circuits 234A, 235A, and 236A, and the other signals B to H are similarly processed.

  Each of the delay circuits 234A to 234H, 235A to 235H, 236A to 236H delays the input signals so that the three signals input to the adders 237A to 237H are in phase.

  The adder 237A adds the output signal (signal A) of the delay 234A, the output signal (signal B) of the delay 235B, and the output signal (signal C) of the delay 236C, and outputs the result. Similarly, the adder 237B adds and outputs the delayed signals B, C, and D, and the adder 237C adds the delayed signals C, D, and E, respectively. The adder 237D adds the signal D, the signal E, and the signal F that have been subjected to the delay processing, and outputs the result. Further, the adder 237E adds and outputs the delayed signals E, F, and G, and the adder 237F adds the delayed signals F, G, and H to the output. The adder 237G adds and outputs the delayed signals G, H, and A, and the adder 237H adds the delayed signals H, A, and B, respectively, and outputs the result. To do. As a result, the collected sound signals from the three adjacent microphones are added in phase. As a result, the signal intensity in the specific direction is further increased, the S / N ratio is improved, and the directivity in the specific direction is further enhanced. The number of signals to be added is not limited to three, and the S / N ratio in a specific direction can be improved by adding or subtracting more signals.

  The microphone signal processing circuit 23 shown in FIGS. 10 and 11 has a configuration in which the output signals A to H of the A / D converters 22A to 22H are directly processed. However, the microphone signal processing circuit 23 is generated using the circuit shown in FIG. The corrected signals A to H may be input. Thereby, the S / N ratio is further improved.

It is a figure which shows the structure of the principal part of the sound emission and collection apparatus which concerns on 1st Embodiment. 4 is a diagram illustrating a distance between a second surface 10B of the housing 1 and a reflecting surface of the reflecting plate 13. FIG. It is the figure which showed the case where the two users 201 and 202 use the sound emission and collection apparatus 100 of 1st Embodiment. It is a side view which shows the other structure of the sound emission and collection apparatus of 1st Embodiment. It is a figure which shows the structure of the principal part of the sound emission and collection apparatus 103 provided with the several speaker which concerns on 2nd Embodiment. It is a figure which shows the main structures of the sound emission and collection apparatus 104 which used the mesh curved board 41 for the supporting member. It is a block diagram which shows the structure of the sound emission and collection apparatus of embodiment of this invention. 3 is a detailed block diagram of a microphone signal processing circuit 23. FIG. This is a detailed block of the echo canceller 24. 6 is a block diagram showing another configuration of the microphone signal processing circuit 23. FIG. 7 is a block diagram of a signal synthesis unit in another microphone signal processing circuit 23. FIG.

Explanation of symbols

100-Sound emitting and collecting device, 200-Desk, 201, 202-User, 300-Sound emitted, 301, 302-Speech sound,
1-housing, 10A-first surface of housing 1, 10B-second surface of housing 1, 10C-side surface of housing 1, 2A-2H-microphone, 3-speaker, 4-support member, 14,15-reflecting plate, 41-curved plate 21A-21H-input amplifier, 22A-22H-A / D converter, 23-microphone signal processing circuit, 231A-231H, 237A-237H-adder, 232-select / mixing Circuit, 233-maximum signal strength detection circuit, 234A to 234H, 235A to 235H, 236A to 236H-delay, 24-echo canceller, 241-adaptive filter, 242-adder, 25-input / output interface, 26-input / output Connector, 31-D / A converter, 32-output amplifier

Claims (9)

A housing having a first surface and a second surface facing each other;
A microphone installed on the first surface side of the housing;
A speaker that is installed at substantially the center of the second surface side of the housing, has a sound emitting surface parallel to the second surface, and emits sound from the second surface to the outside of the housing;
A reflector disposed at a predetermined distance from the second surface to the outside,
A sound emitting and collecting apparatus, wherein a distance between a reflecting surface of the reflecting plate and the second surface is gradually increased from a speaker arrangement position on the second surface to an end portion of the second surface.   2. The sound emission and collection device according to claim 1, wherein the reflection plate has a shape that gradually protrudes toward the second surface side from a side with respect to an end portion of the second surface to a side with respect to a speaker arrangement position of the second surface. . The microphone is a plurality of single units arranged substantially symmetrically on the first surface and arranged symmetrically with respect to the center of the circle, and each having a directivity axis toward the center of the circle. It consists of a unidirectional microphone
The center of the circle formed by the plurality of unidirectional microphones and the center of the speaker are located on the same vertical line with respect to the first surface and the second surface. Sound emitting and collecting device. A housing having a first surface and a second surface facing each other;
A microphone installed on the first surface side of the housing;
A plurality of speakers that are arranged circumferentially with respect to the approximate center on the second surface side of the housing and emit sound from the second surface to the outside of the housing;
A reflector disposed at a predetermined distance from the second surface to the outside,
A sound emitting and collecting apparatus, wherein a distance between a reflecting surface of the reflecting plate and the second surface is gradually increased from a speaker arrangement position on the second surface to an end portion of the second surface.   5. The sound emission and collection device according to claim 4, wherein the reflecting plate has a shape that gradually protrudes toward the second surface from a side with respect to an end of the second surface toward a center of a circle formed by the plurality of speakers.   The reflector touches the second surface on the center side of a circle formed by a plurality of speakers, and the distance between the reflecting surface and the second surface extends from the speaker placement position on the second surface to the end of the second surface. 6. The sound emission and collection device according to claim 5, wherein the sound emission and collection device is formed in a gradually increasing shape. The microphone is a plurality of single units arranged substantially symmetrically on the first surface and arranged symmetrically with respect to the center of the circle, and each having a directivity axis toward the center of the circle. It consists of a unidirectional microphone
The center of a circle formed by the plurality of unidirectional microphones and a center of a circle formed by the plurality of speakers are located on the same vertical line with respect to the first surface and the second surface. The sound emission and collection device according to claim 6.   The said 2nd surface is formed in the shape from which the distance of this 2nd surface and the said 1st surface becomes short gradually from the center of this 2nd surface to the edge part of this 2nd surface. Item 8. The sound emission and collection device according to any one of Items 7 to 9.   The support portion that separates the second surface and the reflection plate by a predetermined distance is formed by a mesh-like member disposed along the second surface and an end portion of the reflection plate. The sound emission and collection device according to any one of the above.

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