JP2004343256A - Loudspeaker system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a loudspeaker system in which a microphone is provided on a loudspeaker and the propagation of vibration from the loudspeaker being a vibrating source to the microphone is suppressed over a broad frequency band. <P>SOLUTION: The loudspeaker system includes: a single loudspeaker 15; a loudspeaker box 20 for tightly closing behind the loudspeaker 15; a directive microphone 40 placed in front of a sound output direction A1 of the loudspeaker 15; and a plurality of filter members 50, 51, 60 provided on a path for vibration propagation from the loudspeaker 15 to the directive microphone 40 and attenuating the vibration. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a speaker device.
[0002]
[Prior art]
A technology has been disclosed in which a voice of an attendee in a conference is received by a microphone, and the voice is spread over a wide area using a single speaker and a reflector (see Patent Document 1).
In the above technique, a microphone is arranged on a speaker. The back side of the speaker is sealed by a speaker box. A microphone is arranged on this speaker box.
[0003]
[Patent Document 1]
JP-A-2003-87887
[Problems to be solved by the invention]
By the way, in the above technique, since the microphone is arranged on a speaker (speaker box) which is a vibration source, it is necessary to suppress the propagation of the vibration to the microphone. For this reason, in Patent Literature 1, measures against vibration such as providing a shielding plate between a speaker and a microphone or providing a cushion material are taken.
However, since there is vibration called so-called box noise of the speaker box due to the back pressure of the speaker, it is difficult to sufficiently suppress the propagation of the vibration to the microphone even if the above-described vibration countermeasures are taken. Was.
In addition, even if a countermeasure against vibration such as provision of a cushion material is taken, it is effective in attenuating vibration in a specific frequency band, but it is difficult to attenuate vibration over a wide band.
[0005]
The present invention has been made in view of the above-described problems, and an object of the present invention is to suppress the propagation of vibration from a speaker as a vibration source to a microphone in a wide frequency band in a speaker device including a microphone on a speaker. It is an object of the present invention to provide a loudspeaker device capable of performing the following.
[0006]
[Means for Solving the Problems]
A speaker device according to a first aspect of the present invention includes a single speaker, a speaker box that seals the back of the speaker, a directional microphone disposed in front of the speaker in a sound output direction, and a speaker. And a plurality of different filter members provided on a path for transmitting vibration reaching the directional microphone.
[0007]
A speaker device according to a second aspect of the present invention is provided on a single speaker, a speaker box that seals the back of the speaker, and a front of the speaker in an audio output direction and on the speaker box. It has a directional microphone, a wall plate of the speaker box provided with the directional microphone, and restraint means for partially restraining relative movement between a wall plate facing the wall plate.
[0008]
In the speaker device according to the first aspect of the present invention, vibration from the speaker is attenuated by a plurality of different filter members provided on a vibration transmission path from the speaker to the directional microphone. Due to different filter members, vibrations in different bands are attenuated.
[0009]
In the speaker device according to the second aspect of the present invention, the relative movement between the opposing wall plates of the speaker box is partially restricted by the restriction means. When the sound pressure fluctuates in the speaker box, movement of the portion constrained by the constraining means is constrained, and the number of nodes increases as compared with the case where the constraining means is not constrained. Vibration is greatly suppressed at or near the restraint position of the wall plate restrained by the restraint means. Further, the increase in the number of nodes increases the frequency of vibration and suppresses the amplitude.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an appearance of a speaker device according to an embodiment of the present invention.
Note that the speaker device 1 according to the present embodiment is a device in which a microphone and a speaker used in a remote conference such as a video conference are integrated, for example, the voice of a participant in the conference room is input by the microphone. This is a device for receiving and loudspeaking voice from the other party through a speaker.
As shown in FIG. 1, the speaker device 1 according to the present embodiment includes a cover member 2, a holding member 3, a speaker 15, and a speaker box 20.
The holding member 3 and the speaker box 20 are made of, for example, a resin such as ABS (acrylonitrile-butadiene-styrene).
The cover member 2 is provided on the holding member 3 and covers the upper surface side of the holding member 3. The cover member 2 is formed of a material that transmits sound, such as a resin fiber, and protects a later-described printed wiring board and a microphone held on the holding member 3. The holding member 3 is supported on the speaker box 20 via a plurality of support members 10 erected on the speaker box 20.
[0011]
FIG. 2 is a plan view of the holding member 3 with the cover member 2 provided on the holding member 3 removed.
FIG. 3 is a sectional view showing the internal structure of the speaker device according to the present embodiment. As shown in FIG. 2, the holding member 3 has a circular outer shape, and the printed wiring board 30 is held in the circle.
[0012]
The printed wiring board 30 has a disk shape, and a plurality of directional microphones 40 are provided on the printed wiring board 30.
Various electronic components (not shown) are mounted on the printed wiring board 30 in addition to the directional microphone 40. The electronic components mounted on the printed wiring board 30 constitute circuits necessary for the electrical operation of the speaker device 1, such as an echo canceller circuit, a circuit for driving a directional microphone 40, and a speaker described later.
[0013]
The plurality of directional microphones 40 have a cylindrical shape, are radially arranged from the center of the printed wiring board 30, that is, are arranged radially from the center, and are arranged at regular intervals in the circumferential direction. Have been.
The directional microphones 40 have directivity in the radial direction from the center of the printed wiring board 30.
Both ends of the directional microphone 40 are supported on the printed wiring board 30 by the filter member 60. The filter member 60 is an embodiment of the second filter member of the present invention.
The filter member 60 is obtained, for example, by molding rubber or resin into a predetermined shape.
The filter member 60 attenuates the vibration transmitted from the printed wiring board 30 side.
[0014]
Wiring is connected to the rear end of the directional microphone 40, and this wiring is connected to the printed wiring board 30 via a connector CN. As a result, the audio signal detected by the directional microphone 40 is input to an electric circuit formed on the printed wiring board 30.
[0015]
As shown in FIG. 3, the printed wiring board 30 is held on the upper surface side of the holding member 3.
More specifically, as shown in FIG. 7, a shaft 3t is formed integrally on the upper surface side of the holding member 3 so as to protrude, and a ring-shaped filter member 51 is inserted into the shaft 3t. A through hole 30h is formed in the printed wiring board 30, and the shaft 3t is inserted into the through hole 30h. The printed wiring board 30 is provided on the filter member 51. Further, the annular filter member 50 is provided on the outer periphery of the shaft portion 3t, and is disposed on the printed wiring board 30.
[0016]
A screw hole is formed in the center of the shaft portion 3t, and a bolt 56 is screwed into the screw hole via an annular holding plate 57. As a result, the holding plate 57 holds down the upper surface of the filter member 50, and the printed wiring board 30 is sandwiched between the filter member 50 and the filter member 51. That is, the printed wiring board 30 is supported by the filter members 50 and 51.
The filter members 50 and 51 are one embodiment of the first filter member of the present invention.
The filter members 50 and 51 are formed of a material such as rubber or resin, and have the same shape. The filter members 50 and 51 have a natural frequency different from that of the filter member 60.
[0017]
The speaker box 20 includes an upper side wall plate 21 and a lower side wall plate 22.
The upper side wall plate 21 and the lower side wall plate 22 have a circular outer shape. A single speaker 15 is fixed to the center of the upper side wall plate 21.
As the speaker 15, for example, a cone speaker is used. The speaker 15 outputs in the audio output direction A1 by vibrating a diaphragm (not shown) along the direction of the audio output direction A1 indicated by the arrow.
[0018]
The speaker box 20 seals the back of the speaker 15. A seal member 80 is provided between the upper side wall plate 21 and the lower side wall plate 22, and the inside of the speaker box 20 is a closed space.
[0019]
On the lower surface side of the upper side wall plate 21, a support portion 21t extending toward the lower side wall plate 22 is integrally formed.
On the upper surface side of the lower side wall plate 22, a protruding portion 22a protruding toward the upper side wall plate 21 side is formed.
The lower end surface of the support portion 21t is in contact with the upper end surface of the protruding portion 22a.
A through hole 21p is formed at the center of the support portion 21t, and a female screw portion 21h is formed at the upper end side of the through hole 21p.
A female screw portion 22h is also formed on the protruding portion 22a.
[0020]
The coupling bolt 11 is inserted into the through hole 21p of the support portion 21t from the side of the protruding portion 22a. The coupling bolt 11 is formed on the female screw portion 21h formed on the upper wall plate 21 and the lower wall plate 22. It is screwed into both of the female screw portions 22h.
The coupling bolt 11 is formed of a metal material such as steel, and has sufficiently higher rigidity than the resin material forming the speaker box 20 and the holding member 3.
The connecting bolt 11 is an embodiment of the connecting member of the present invention. The coupling bolt 11 and the female screw portions 21h, 22h constitute a restraining means of the present invention for partially restraining relative movement between the opposing wall plates 21, 22 of the speaker box 20.
[0021]
The coupling bolt 11 passes through the female screw portion 21h and is screwed into a female screw portion 3h formed on the protection member 3. Thereby, the relative positions of the female screw portion 21h of the upper wall plate 21, the lower wall plate 22h, and the female screw portion 3h of the protection member 3 are restricted.
A plurality of support members 10 are provided between the lower side surface of the protection member 3 and the upper side wall plate 21. The support member 10 has a through hole 10h formed therein, and a coupling bolt 11 is inserted into the through hole 10h.
[0022]
Next, with reference to FIG. 4, the configuration and operation of the reflection surface 3f on the holding member 3 side and the reflection surface 21f on the speaker box side will be described.
[0023]
The reflecting surface 3f and the reflecting surface 21f reflect the sound from the speaker 15, and diffuse the sound radially around the speaker 15 in a direction substantially orthogonal to the sound output direction A1 of the speaker 15.
[0024]
As shown in FIG. 4, the reflection surface 3f is formed of a curved surface that protrudes smoothly toward the speaker 15 side. The reflection surface 3f is substantially constituted by, for example, a rotating curved surface formed when a hyperbola is rotated around the central axis Ct of the speaker 15 as a rotation axis.
Similarly, the reflection surface 21f is also substantially constituted by a rotating curved surface having the center axis Ct of the speaker 15 as a rotation axis.
[0025]
The radii of the speaker 15 from the center axis Ct are R1, R2, and R3, and the distances between the reflecting surface 3f and the reflecting surface 21f at the radii R1, R2, and R3 are L1, L2, and L3. As can be seen from FIG. 4, as the distance from the center axis Ct of the speaker 15 increases, the distance between the reflection surface 3f and the reflection surface 21f continuously increases.
[0026]
For example, if the distance between the reflection surface 3f and the reflection surface 21f is constant, resonance occurs at a resonance frequency corresponding to the constant distance.
When resonance occurs, the sound becomes very difficult to hear, and the voice of the attendees of the conference cannot be faithfully reproduced.
[0027]
On the other hand, according to the present embodiment, the distance between the reflecting surface 3f and the reflecting surface 21f continuously increases as the distance from the central axis Ct of the speaker 15 increases, so that the sound output from the speaker 15 has a specific frequency. There is no resonance.
For this reason, it is possible to faithfully reproduce the voice uttered by the attendees of the conference.
According to the present embodiment, the sound output from the speaker 15 is substantially orthogonal to the center axis Ct about the center axis Ct of the speaker 15 in a direction different from the sound output direction A1 of the speaker 15 without resonance. In all directions (360 ° radial). Particularly, since the single speaker 15 is used, the sound does not interfere around the central axis Ct, and the sound is spread evenly.
Furthermore, since there is no resonance between the reflection surface 3f and the reflection surface 21f, it is possible to diffuse sound more efficiently and far.
[0028]
Next, the operation and effect of the coupling bolt 11 will be described.
FIGS. 6A and 6B are schematic diagrams illustrating an example of vibration of the speaker box when the coupling bolt 11 does not exist. FIG. 6A illustrates a case where the sound pressure in the speaker box is low, and FIG.
As shown in FIG. 6, when the sound pressure in the speaker box fluctuates, the upper side wall plate 21 and the lower side wall plate 22 vibrate in opposite directions.
At this time, assuming that the connection position of the support member 10 to the upper side wall plate 21 is Cp, the connection position Cp vibrates due to the sound pressure fluctuation in the speaker box.
[0029]
FIG. 5 is a schematic diagram illustrating an example of vibration of the speaker box 20 according to the present embodiment.
As shown in FIG. 5, the upper side wall plate 21 and the lower side wall plate 22 are connected by connecting bolts 11.
When the sound pressure in the speaker box 20 fluctuates, the upper side wall plate 21 and the lower side wall plate 22 vibrate in opposite directions, but do not vibrate because the connection position Cp is restricted by the coupling bolt 11.
[0030]
In the present embodiment, since the connection position Cp is restrained by the coupling bolt 11 and hardly vibrates, the vibration does not easily propagate to the holding member 3 connected by the coupling bolt 11 and the support member 10 at this position. That is, the vibration directly transmitted from the speaker box 20 to the holding member 3 on which the microphone 40 is mounted is suppressed.
[0031]
The position restrained by the connecting bolt 11 is a new node of vibration. That is, the vibration frequency of the speaker box 20 also increases due to the formation of a new node.
By actively using the change in the frequency of the vibration, the vibration of the speaker box 20 can be changed to a vibration frequency that does not substantially affect the microphone 40.
Further, by changing the vibration frequency of the speaker box 20 to a frequency that can be easily attenuated by the above-described filter members 50, 51, 60, etc., the vibration suppression by the filter members 50, 51, 60 can be performed efficiently.
[0032]
Next, the operation and effect of the filter members 50, 51, 60 will be described with reference to FIG.
As shown in FIG. 7, vibrations from the speakers 15 and the speaker box 20 that are vibration sources propagate from the reflection surface 3f of the holding member 3 to the printed wiring board 30 through the filter members 50 and 51, for example. Further, the vibration propagated to the printed wiring board 30 propagates through a wire connecting the microphone 40 with the filter member 60 or the connector CN.
[0033]
Here, the filter members 50 and 51 support a relatively heavy weight on the printed wiring board 30, the plurality of microphones 40, and the like. For this reason, the filter members 50 and 51 have an effect of attenuating vibration at a relatively low frequency. However, it is difficult to simultaneously attenuate even relatively high frequency vibrations.
Therefore, the relatively high frequency vibration is attenuated by the filter member 60 provided between the microphone 40 and the printed wiring board 30. The weight supported by the filter member 60 is relatively small, and relatively high frequency vibration can be attenuated relatively easily.
[0034]
As described above, when the sound from the speaker 15 is reflected and amplified by the reflection surfaces 3f and 21f, resonance is not positively generated, so that vibration in a very wide frequency band is transmitted from the speaker 15 to the microphone 40. Attempt to propagate.
According to the present embodiment, it is possible to attenuate the vibration in a wide band by combining filter members having different natural frequencies with the vibration in the wide frequency band.
[0035]
The invention is not limited to the embodiments described above.
In the above-described embodiment, the case where the connecting bolt 11 is used as the restraining means of the present invention has been described. However, any means other than the connecting bolt 11 may be used as long as it can connect the upper wall plate 21 and the lower wall plate 22. It is possible.
Further, the connecting position between the holding member 23 and the upper side wall plate of the speaker box 20 is set to a position restrained by the connecting bolt 11, but the holding member 23 and the upper side wall plate of the speaker box 20 are connected near this position. The connection may be made by a connection member different from the bolt 11.
Also, the first and second filter members of the present invention have been described by taking the filter members 50, 51, and 60 as examples, but other filter members can be used, The location can also be changed as appropriate.
[0036]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, propagation of the vibration from the speaker which is a vibration source to a microphone can be suppressed in a wide frequency band.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an appearance of a speaker device according to an embodiment of the present invention.
FIG. 2 is a plan view showing a structure of a printed wiring board held by a holding member.
FIG. 3 is a sectional view showing the internal structure of the speaker device according to one embodiment of the present invention.
FIG. 4 is a diagram for explaining a positional relationship between a reflection surface on a holding member side and a reflection surface on a speaker box side;
FIG. 5 is a schematic diagram illustrating an example of vibration of a speaker box.
FIG. 6 is a schematic diagram illustrating an example of vibration of a speaker box when a coupling bolt does not exist.
FIG. 7 is a cross-sectional view for explaining the operation of the filter member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Speaker apparatus, 2 ... Cover member, 3 ... Holding member, 3f ... Reflection surface, 3h ... Female screw part, 10 ... Support member, 11 ... Coupling bolt, 15 ... Speaker, 20 ... Speaker box, 21 ... Upper wall plate, Reference numeral 21f: reflection surface, 21h: female screw portion, 22: lower side wall plate, 22h: female screw portion, 30: printed wiring board, 40: microphone, 50, 51: filter member, 60: filter member, 80: seal member, CN ... connector.

Claims (9)

A single speaker,
A speaker box for sealing the back of the speaker,
A directional microphone disposed in front of the audio output direction of the speaker,
A speaker device comprising: a plurality of different filter members provided on a path for transmitting vibration from the speaker to the directional microphone; The speaker device according to claim 1, wherein the filter members have different natural frequencies. A printed wiring board having a circuit for driving the speaker and the directional microphone,
And a holding member provided on the speaker box, for holding the printed wiring board,
A first filter member configured to support the printed wiring board with respect to the holding member,
The speaker device according to claim 1, further comprising a second filter member that supports the directional microphone on the printed wiring board. The directional microphone has a cylindrical shape,
The speaker device according to claim 3, wherein the second filter member supports both ends of the directional microphone. A single speaker,
A speaker box for sealing the back of the speaker,
A directional microphone provided on the speaker box in front of the audio output direction of the speaker,
A speaker device comprising: a wall plate of the speaker box provided with the directional microphone; and a restraining unit that partially restrains relative movement between a wall plate facing the wall plate. A printed wiring board having a circuit for driving the speaker and the directional microphone,
And a holding member provided on the speaker box, for holding the printed wiring board,
The speaker device according to claim 5, wherein the holding member is connected to a position of the wall plate of the speaker box restrained by the restraining means or near this position by a connecting member. The constraining means includes a female screw portion formed on each of the opposed wall plates of the speaker box,
The speaker device according to claim 5, further comprising: a coupling member screwed to the female screw portion. The speaker box is made of resin,
The speaker device according to claim 7, wherein the coupling member is made of metal. The holding member has a female screw portion with which the coupling member is screwed,
The speaker device according to claim 7, wherein the coupling member partially restricts relative movement between the wall plates and between the wall plate and the holding member.

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