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JP2006229803

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DESCRIPTION JP2006229803
PROBLEM TO BE SOLVED: To inexpensively provide an outdoor speaker capable of controlling a
pointing direction. SOLUTION: A directional plate 5 having a thin plate shape is provided inside a
horn 4 having a cylindrical body, and the directional direction of an outdoor speaker is changed
by rotating the directional plate 5 around a rotation axis 6. Can. The pointing plate 5 transitions
between a first state perpendicular to the diaphragm 3 of the sound producing body 2 and a
second state in which the end portion is in contact with the inner surface of the horn 4, and the
outer peripheral shape is It corresponds to the inner surface shape of the horn 4 in contact in the
second state. [Selected figure] Figure 1
Outdoor speaker and outdoor sound system
[0001]
The present invention relates to an outdoor speaker and an outdoor sound system, and more
particularly, to a directional control of a loudspeaker system covering a relatively wide listening
area outdoors, for example, an outdoor speaker used in a disaster prevention broadcasting
system.
[0002]
The disaster prevention broadcasting system is a loud speaker system that reports voice
information using a speaker installed outdoors, and when a disaster occurs, disaster information,
evacuation information, and the like are reported, and public information information of the local
government and time newsletter melody Are notified.
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1
In such a disaster prevention broadcasting system, the listening area is determined in advance in
consideration of administrative divisions, topography, etc., and normally, a relatively large
outdoor area is used as the listening area. For example, there are cases where it covers up to
several kilometers away from an outdoor speaker.
[0003]
In a disaster prevention broadcasting system in which such a large outdoor area is used as a
listening area, the reachable area of broadcast sound fluctuates under the influence of
environmental conditions such as temperature and wind. For this reason, there is a problem that
a point where the broadcast sound does not sufficiently reach even in a predetermined listening
area occurs, or the broadcast sound reaches the outside of the listening area with a large volume.
Therefore, if the pointing direction of the outdoor speaker can be controlled according to such
environmental conditions, it is considered that the above problem can be alleviated.
[0004]
Some conventional outdoor sound systems are capable of controlling the pointing direction
according to weather conditions (for example, Patent Document 1). In the outdoor sound system
of Patent Document 1, a large number of speakers are arranged, and phase control is performed
on sound signals supplied to the speakers to control the directivity direction of the sound output
from the speaker group. An outdoor sound system using such a speaker group has a problem of
being expensive. JP 10-93514 A
[0005]
Generally, in an outdoor sound system that uses a wide range of outdoor areas as a listening
area, a large-sized speaker is adopted because an output of a large volume is required for the
speaker. For example, in the case of a disaster prevention broadcasting system, a speaker having
a horn of about 50 cm to 2 m is often used. Moreover, in order to enlarge a listening area, it is
installed in a high position in many cases using a pillar etc.
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[0006]
If such an outdoor speaker is to be subjected to attitude control to change the pointing direction,
a drive device having a large driving force is required, and the installation work becomes
difficult, resulting in an expensive system. Moreover, since it is installed outdoors, it is thought
that it is easy to be damaged by dirt, rust etc.
[0007]
The present invention has been made in view of the above-mentioned circumstances, and an
object thereof is to provide an outdoor speaker whose directional direction can be controlled at
low cost. Another object of the present invention is to inexpensively provide an outdoor sound
system that controls the pointing direction of the outdoor speaker according to the
environmental conditions.
[0008]
The outdoor speaker according to the first aspect of the present invention controls a horn made
of a cylindrical body attached to a sounding body, a directional plate made of a plate provided in
the horn, and an angle of the directional plate with respect to the horn And a plate drive unit.
With such a configuration, it is possible to change the pointing direction of the outdoor speaker
by changing the angle of the pointing plate, and therefore, changing the pointing direction with a
smaller driving force than in the case of performing attitude control of the outdoor speaker itself.
be able to. Therefore, the outdoor speaker which can control a pointing direction can be provided
inexpensively.
[0009]
In the outdoor speaker according to the second aspect of the present invention, in addition to the
above configuration, the horn has a shape in which the cross section is gradually enlarged in
accordance with the distance to the sounding body, and the plate drive unit A first state in which
the pointing plate is rotationally driven around a parallel rotation axis, and the plate drive unit is
parallel to a pointing direction of the horn when the pointing plate does not have the pointing
plate, and the pointing plate And a second state in which the end on the sound producing body
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side is brought into contact with the inner surface of the horn. According to such a configuration,
it is possible to switch the pointing direction while suppressing the deterioration of the acoustic
characteristics by utilizing the inner surface shape of the horn.
[0010]
In the outdoor speaker according to the third aspect of the present invention, in addition to the
above configuration, the directional plate is configured such that the outer peripheral shape
matches the shape of the inner surface of the horn in contact in the second state. With such a
configuration, it is possible to switch the pointing direction while suppressing the deterioration
of the acoustic characteristics more effectively.
[0011]
According to a fourth aspect of the present invention, there is provided an outdoor sound system
including a wind direction meter for measuring a wind direction, an outdoor speaker capable of
controlling a pointing direction, and a pointing control device for performing pointing control of
the outdoor speaker based on measurement results of the wind direction meter. An outdoor
acoustic system comprising: a horn comprising a cylindrical body attached to the sounding body;
a directional plate having a thin plate shape provided in the horn; And a plate drive for
controlling the angle of the plate. With such a configuration, it is possible to inexpensively
provide an outdoor sound system that controls the pointing direction of the outdoor speaker
according to the wind direction.
[0012]
In the outdoor acoustic system according to the fifth aspect of the present invention, in addition
to the above configuration, the anemoscope measures the wind direction in the horizontal plane,
and the outdoor speaker can control the pointing direction in the vertical direction. However, the
outdoor speaker is controlled such that the pointing direction of the outdoor speaker in the case
of a tailwind is higher than the pointing direction in the case of a headwind. With such a
configuration, the pointing direction of the outdoor speaker can be controlled in the vertical
direction based on the wind direction in the horizontal plane, and the influence of winds different
in speed according to the altitude can be suppressed to secure an appropriate listening area. Can.
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[0013]
An outdoor audio system according to a fifth aspect of the present invention is an outdoor audio
system including an outdoor speaker capable of controlling a pointing direction, and a pointing
control device for performing pointing control of the outdoor speaker with a period of 1 day
based on time. The outdoor speaker comprises a horn comprising a cylindrical body attached to a
sounding body, a directional plate having a thin plate shape provided in the horn, and a plate
drive for controlling an angle of the directional plate with respect to the horn Have a part. With
such a configuration, it is possible to control the pointing direction according to the time of day
and to secure an appropriate listening area throughout the day.
[0014]
According to a sixth aspect of the present invention, in the outdoor sound system according to
the sixth aspect of the present invention, the pointing control device changes the pointing
direction at predetermined first and second times such that the pointing direction at night is
higher than the pointing direction at daytime. , Configured to control the outdoor speaker. Such a
configuration can ensure an appropriate listening area throughout the day and night when the
temperature gradient of air with respect to altitude changes.
[0015]
According to the present invention, it is possible to inexpensively provide an outdoor speaker
that can control the pointing direction. In addition, it is possible to inexpensively provide an
outdoor sound system that controls the pointing direction of the outdoor speaker according to
the environmental conditions.
[0016]
Embodiment 1 FIG. 1 is a diagram showing an example of the configuration of the outdoor
speaker according to Embodiment 1 of the present invention. The illustrated outdoor speaker 1 is
configured by attaching a horn 4 to a sound generator 2, and a directional plate 5 is provided
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inside the horn 4. The direction in which the outdoor speaker 1 is pointed can be changed by the
plate driving units 7A and 7B rotationally driving the pointing plate 5.
[0017]
The sounding body 2 has a diaphragm 3 for converting an electrical signal into a sound pressure,
and generates a desired sound wave. The sound waves generated by the sound generator 2 pass
through the horn 4 and are emitted in a pointing direction determined by the shape of the
internal space.
[0018]
The horn 4 is a cylindrical body having an open upper surface and a lower surface of the
truncated cone, and the opening on the upper surface side is attached to the sound producing
body 2 so that the central axis is perpendicular to the diaphragm 3 of the sound producing body
2 It is done. Therefore, the cross section of the horn 4 gradually expands as the distance from the
sounding body 2 increases, and the sound wave from the sounding body 2 enters from the
narrow opening (incidence port) and widens through the horn 4. It is emitted from the opening
(exit).
[0019]
The directing plate 5 is a thin plate provided inside the horn 4 and is rotatably attached to the
rotation axis 6. The rotation axis 6 is a rotation axis parallel to the main surface of the directional
plate 5, and the angle of the directional plate 5 with respect to the horn 4 can be adjusted by
rotating the directional plate 5. In the present embodiment, the end of the directional plate 5 is
made to coincide with the exit of the horn 4, and the rotation shaft 6 is also provided on the exit
of the horn 4.
[0020]
The plate driving units 7A and 7B perform rotational driving of the pointing plate 5. The plate
driving units 7A and 7B are respectively configured by a wire 70, a guide roller 72, and a motor
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73. One end of the wire 70 is fixed to the directional plate 5 and is pulled out from the small hole
71 provided on the side surface of the horn 4, and the other end is provided via a guide roller 72
provided on the outer surface of the horn 4. It is connected to the motor 73. Therefore, the motor
73 can rotate the pointing plate 5 by winding the wire 70.
[0021]
The point of action on the directional plate 5 to which the wire 70 is attached is provided closer
to the sounding body 2 than the rotating shaft 6. Therefore, the side of the sounding body 2 of
the pointing plate 5 can be moved up and down by the plate driving units 70A and 70B.
[0022]
The plate drivers 7A and 7B have the same structure and drive the pointing plates 5 in opposite
directions. That is, when the plate drive unit 7A winds up the wire 70, the plate drive unit 7B
unrolls the wire 70, and the pointing plate 5 rotates upward. On the other hand, when the plate
drive unit 7B winds up the wire 70, the plate drive unit 7A unrolls the wire 70, and the pointing
plate 5 rotates downward.
[0023]
FIG. 2 is a cross-sectional view of the outdoor speaker 1 of FIG. 1 cut along the A-A cutting line,
and in (a) to (c) in the drawing, there are three stationary states in which the pointing plate 5
transitions. It is shown. FIG. 3 is a cross-sectional view of the speaker of FIG. 1 cut along the B-B
cut surface.
[0024]
FIG. 2A shows a state in which the pointing plate 5 is disposed parallel to the original pointing
direction of the horn 4. The directional direction of the horn 4 in the case where the directional
plate 5 is not provided is the direction of the central axis, and in the case of (a), the directional
plate 5 is parallel to the central axis. It hardly affects the pointing direction of the outdoor
speaker 1. In this specification, this state is called a normal position.
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[0025]
FIG. 2B shows a state in which the pointing plate 5 is rotated upward from the state of FIG. 2A
and the pointing plate 5 is in contact with the inner surface of the horn 4. By bringing the end on
the sounding body 2 side of the pointing plate 5 into contact with the upper surface of the inner
surface of the horn 4, the sound wave from the sounding body 2 passes through the space below
the pointing plate 5 and is more than in the normal position. It is also emitted downward. This
state is called a down position. At this time, since the main surface of the directional plate 5 has
an inclination close to the lower side of the inner surface of the horn 4, it is possible to turn the
directivity direction downward while suppressing deterioration of acoustic characteristics such as
volume and sound quality. it can.
[0026]
Further, as shown in FIG. 3, the directional plate 5 has its outer peripheral shape matched to the
shape of the inner surface of the horn 4, and in the state of (b) of FIG. There is no gap that
significantly affects the characteristics and directional characteristics. For this reason, in the state
of (b), the sound wave from the sounding body 2 does not substantially pass through the space
above the pointing plate 5, and the pointing direction is reduced while the deterioration of the
acoustic characteristics is more effectively suppressed. I'm pointing down.
[0027]
FIG. 2C shows a state in which the pointing plate 5 is rotated downward from the state of FIG. 2A
and the end of the pointing plate 5 is in contact with the inner surface of the horn 4. If the shape
of the horn 4 is symmetrical with respect to the plane including the central axis of the horn 4 and
the rotation axis 6 of the pointing plate 5, a significant gap occurs between the pointing plate 5
and the inner surface of the horn 4 even in the state of (b). Absent. For this reason, in the state of
(c), the sound wave from the sounding body 2 can pass through the space above the pointing
plate 5 and can direct the pointing direction of the outdoor speaker 1 upward than in the normal
position. This state is called an up position.
[0028]
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8
Thus, in the down position of FIG. 2 (b) and the up position of FIG. 2 (c), a part of the internal
space of the horn 4 for transmitting the sound pressure is cut off by the pointing plate 5. The
pointing direction can be changed up and down without significantly disturbing the pressure.
That is, the pointing direction of the outdoor speaker 1 can be changed only by changing the
angle of the pointing plate 5 inside the horn 4 while the sounding body 2 and the horn 4 are
fixed. Therefore, the movable portion can be reduced in weight as compared with the case where
attitude control of the entire speaker is performed, and the pointing direction can be changed by
a small driving force.
[0029]
Here, the driving force required for the motor 73 becomes smaller as the point of action on the
directional plate 5 to which the wire 70 is attached is farther from the rotating shaft 6. For this
reason, it is desirable that the pointing plate 5 be provided with the rotation axis 6 near the end
on the exit side and the action point be provided near the end on the entrance side. In FIG.1 and
FIG.3, the rotating shaft 6 is provided in the output port, and the action point is provided in the
edge part of the directional plate 5 closest to the entrance port.
[0030]
According to the present embodiment, the directivity direction of the outdoor speaker 1 is
controlled by controlling the angle of the directivity plate 5 provided inside the horn 4. For this
reason, even in the case of a large speaker, the pointing direction can be easily changed by a
small driving force. In addition, since the directional plate 5 inside the horn 4 is driven, it is
possible to make it less susceptible to the effects of dirt and rust that easily occur when installed
outdoors.
[0031]
Moreover, according to the present embodiment, the outer peripheral shape of the pointing plate
5 matches the inner surface shape of the horn 4 that abuts in the down position and the up
position. For this reason, a part of the internal space of the horn 4 is completely cut off by the
pointing plate 5, and deterioration of the acoustic characteristics in the horn 4 can be
03-05-2019
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suppressed.
[0032]
In the above embodiment, an example in which the horn 4 has a shape of a truncated cone has
been described, but the present invention is not limited to such a case. That is, the horn 4 may
have a shape in which the cross section gradually expands in accordance with the distance from
the sounding body 2. For example, it may be shaped like a trumpet in which the cross section is
enlarged in an accelerated manner, or the cross section may be square.
[0033]
Further, in the present embodiment, the case where the directional plate 5 is transitioned
between three states has been described, but the present invention is not limited to such a case,
and the transition between the two states may be performed. Good. Specifically, transition may
be made between the normal position and the up position, transition may be made between the
normal position and the down position, or transition may be made between the up position and
the down position.
[0034]
In the above embodiment, an example of the outdoor speaker in which one sounding body 2 is
attached to the horn 4 has been described. However, the present invention is applied to an
outdoor speaker in which two or more sounding bodies are attached to the same horn. It can also
be applied. FIG. 4 is a diagram showing another configuration example of the outdoor speaker
according to the first embodiment. This outdoor speaker is configured by attaching two sounding
members 2a and 2b to the same horn 4 using a Y-shaped connecting tube 8, and the sound
pressure from these sounding members 2a and 2b is a connecting tube. 8 are synthesized and
are incident on the entrance of the horn 4. The propagation path of the sound pressure after
incidence to the horn 4 is the same as in the case of FIG. 1 (Embodiment 1), and the pointing
direction can be switched and controlled by rotationally driving the pointing plate 5. When the
sound pressure from the sounding bodies 2 a and 2 b is not sufficiently mixed in the connecting
pipe 8, the sound pressure bodies 2 a and 2 b should be arranged parallel to the directional plate
5. Is more desirable.
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[0035]
Second Embodiment In Embodiment 1, an example of the outdoor speaker having one directional
plate 5 has been described, but in the present embodiment, an outdoor speaker having two
directional plates 5 will be described.
[0036]
FIG. 5 is a cross-sectional view showing an example of the outdoor speaker according to
Embodiment 2 of the present invention. The outdoor speaker has two directional plates 5A and
5B inside the horn 4. These directional plates 5A, 5B are arranged in parallel, and angle control is
performed by a plate drive unit (not shown).
[0037]
In (a) of the drawing, a normal position in which the directional plates 5A and 5B are disposed in
parallel to the central axis of the horn is shown. In (b), the state (down position) in which the
pointing plates 5A and 5B are rotated upward and the end of the pointing plate 5A is in contact
with the inner surface of the horn 4 is shown. (C) shows a state (up position) in which the
pointing plates 5A and 5B are rotated downward and the end of the pointing plate 5B is in
contact with the inner surface of the horn 4.
[0038]
The pointing plate 5A has the same outer peripheral shape as the inner surface of the horn 4 in
contact in the state of (b), and in the state of (b), a gap having a significant influence is generated
between the inner surface and the horn 4 I will not let you. For this reason, the sound wave from
the sounding body 2 can pass through the space below the pointing plate 5A, and can direct the
pointing direction of the outdoor speaker 1 lower than in the case of the normal position.
[0039]
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11
In addition, pointing plate 5B has the same outer peripheral shape as the inner surface shape of
horn 4 in contact in the state of (c), and in the state of (b), a gap that significantly affects the
inner surface of horn 4 Not cause For this reason, the sound wave from the sounding body 2 can
pass through the space above the pointing plate 5B, and can direct the pointing direction of the
outdoor speaker 1 upward than in the case of the normal position.
[0040]
Third Embodiment In the first embodiment, the case where the directional plate 5 is a thin plate
having a uniform thickness has been described. On the other hand, in the present embodiment,
an example in the case where the thickness of the plate-like member constituting the directional
plate is not uniform will be described.
[0041]
FIG. 6 is a view showing an example of the outdoor speaker according to the third embodiment
of the present invention, and is a cross-sectional view taken along the line A-A in FIG. In (a) to (c)
of the drawing, three stationary states in which the pointing plate 5C transitions are shown.
[0042]
The outdoor speaker has a directional plate 5C inside the horn 4. The pointing plate 5C is formed
of a plate-like body whose thickness is not uniform. The thickness of the pointing plate 5C is
preferably continuously changing, and more preferably smoothly.
[0043]
The pointing plate 5 has the smallest thickness at the end on the entrance side and the exit side,
and the thickness increases from the both ends toward the center. In addition, the thickest
portion is provided on the incident side more than the center of the line connecting the both
ends. For this reason, the space formed by the pointing plate 5C has a shape which is expanded
toward the emission port of the horn 4. That is, the propagation path of the sound pressure
03-05-2019
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adjacent to the main surface of the directional plate 5C can be shaped to be spread toward the
emission port of the horn 4, and the acoustic characteristics are improved compared to the case
where the thickness of the directional plate is uniform. It can be done.
[0044]
In (a) of FIG. 6, the space formed on the upper and lower sides of the directional plate 5C is
shaped so as to expand toward the exit. Further, the space formed below the directional plate 5C
in (b) and the space formed on the upper side of the directional plate 5C in (c) are respectively
shaped so as to expand toward the exit.
[0045]
In the present embodiment, an example of the case where the propagation path of the sound
pressure formed by the pointing plate 5C has a shape having a spread toward the emission port
of the horn 4 has been described. The case is not limited. That is, if the ratio of the crosssectional area on the exit side to the cross-sectional area on the entrance side of the propagation
space adjacent to the pointing plate 5C is increased, the acoustic characteristics and the
directivity characteristic can be improved. The cross-sectional area ratio is desirably 1 or more,
but if the thickness of the directional plate is uniform (the cross-sectional area ratio) in the case
where the thickness is uniform (the first embodiment), the characteristic improvement is An
effect is obtained.
[0046]
Fourth Embodiment FIG. 7 is a schematic view showing an example of the outdoor sound system
according to the fourth embodiment of the present invention, in which an example of a disaster
prevention broadcasting system is shown.
[0047]
The outdoor speakers 11 to 14 are attached to the support 20 and installed at a high position in
order to secure a wide listening area. These outdoor speakers 11 to 14 are attached to the
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support 20 in a desired direction in consideration of the listening area. Here, in order to cover all
directions, it is assumed that four outdoor speakers 11 to 14 are installed at every central angle
of 90 °. In addition, a wind direction meter 21 for measuring the wind direction is also installed
on the support 20.
[0048]
The controller 22 is connected to the disaster prevention center 23 and the broadcast facility 24.
The broadcast facility 24 transmits a regular broadcast signal such as public information and a
time signal melody, and the disaster prevention center 23 transmits an emergency broadcast
signal such as disaster information and evacuation information at the time of occurrence of a
disaster. The controller 22 switches between the normal broadcast signal and the emergency
broadcast signal and outputs the signals to the speakers 11 to 14. This switching operation is
performed based on the switching signal transmitted from the disaster prevention center 23
together with the emergency broadcast signal so as to give priority to the emergency broadcast
signal over the normal broadcast signal.
[0049]
Further, the controller 22 controls the pointing direction of the outdoor speakers 11 to 14 based
on the output of the anemoscope 21. The outdoor speakers 11 to 14 are the outdoor speakers 1
shown in FIG. 1 and control the angle of the directional plate 5 on which the rotation shaft 6 is
disposed horizontally to switch the directional direction in the vertical direction. That is, based on
the wind direction, the pointing direction of the outdoor speakers 11 to 14 is controlled.
[0050]
FIG. 8 is an explanatory view schematically showing the relationship between the wind direction
and the sound propagation direction. Generally, when comparing the wind near the surface of the
ground and the wind at the same point, it goes without saying that the wind direction matches,
but the wind speed is faster in the latter. If there is a difference in sound propagation speed in a
plane perpendicular to the sound propagation direction, the sound propagation direction has the
property of bending toward the slower propagation speed. For this reason, the sound
propagation direction is bent in the vertical direction by the influence of the wind.
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[0051]
The case of tail wind is shown in (a) of the figure. In the case of tailwind, the higher the altitude,
the faster the sound propagation speed, and the propagation direction of the sound emitted from
the outdoor speaker 1 is bent downward. On the other hand, (b) shows the case of headwind. In
the case of a headwind, the higher the altitude, the slower the sound propagation speed, and the
propagation direction of the sound emitted from the outdoor speaker 1 is bent upward.
[0052]
For this reason, the controller 22 controls the pointing direction of each of the outdoor speakers
11 to 14 based on the wind direction, and causes the reach area of the broadcast sound to
coincide with a predetermined listening area. That is, for the outdoor speakers 11 to 14 receiving
a tailwind, the pointing direction is upward, and for the outdoor speakers 11 to 14 receiving the
opposite wind, the pointing direction is downward.
[0053]
FIG. 9 is an explanatory view showing an example of the operation of the controller 22, and
shows a state where the support 20 of FIG. 8 is viewed from above. The controller 22 equally
divides the omnidirectional (360 °) into eight azimuthal ranges D1 to D8 in the horizontal plane,
and determines to which of the azimuthal ranges D1 to D8 the wind direction measured by the
wind direction meter 21 belongs. ing.
[0054]
The azimuth ranges D1, D3, D5, and D7 are azimuth ranges including the directivity directions of
the outdoor speakers 11 to 14 at their centers, and the azimuth ranges D2, D4, D6, and D8 are
sandwiched by the directivity directions of the outdoor speakers 11 to 14. Azimuth range.
[0055]
The case where the wind direction is the azimuth | direction range D3 to which the outdoor
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speaker 11 belongs is shown by (a) in the figure.
In this case, the outdoor speaker 11 is a headwind, and the outdoor speaker 13 is a tailwind.
Therefore, the controller 22 lowers the directivity direction by setting the directivity plate 5 of
the speaker 11 in the down position, and raises the directivity direction by setting the directivity
plate 5 of the outdoor speaker 13 in the up position. At this time, the directional plates of the
outdoor speakers 12 and 14 are in the normal position.
[0056]
The case where the wind direction is the azimuth | direction range D2 to which the outdoor
speakers 11-14 do not belong is shown by (b) in the figure. In this case, the outdoor speakers 11
and 14 belonging to the adjacent azimuth ranges D1 and D3 face each other, and the remaining
outdoor speakers 12 and 13 serve as a tailwind. Therefore, the controller 22 lowers the
directivity direction by setting the directivity plate 5 of the speakers 11 and 14 to the down
position, and raises the directivity direction by setting the directivity plate 5 of the outdoor
speakers 12 and 13 to the up position.
[0057]
According to the present embodiment, the controller 22 controls the pointing direction of the
outdoor speaker in the vertical direction based on the wind direction in the horizontal plane
measured by the wind direction meter 21. For this reason, the propagation direction of the sound
is bent in the vertical direction by the influence of the wind, and it is possible to compensate for
the fluctuation of the listening area, and a desired listening area can be secured.
[0058]
Embodiment 5 In the fourth embodiment, an example of the disaster prevention broadcasting
system in which the pointing direction of the outdoor speakers 11 to 14 is controlled based on
the wind direction has been described. On the other hand, in the present embodiment, a disaster
prevention broadcasting system that controls the pointing direction of the outdoor speakers 11
to 14 based on the time will be described.
03-05-2019
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[0059]
FIG. 10 is an explanatory view schematically showing the relationship between time and the
propagation direction of sound. In general, when the temperature near the surface of the ground
and the temperature at the same point are compared, the former is higher during the day and the
latter is higher during the night. In other words, the magnitude relationship between the two
temperatures is switched on a daily basis. The speed of sound propagation increases as the
temperature of air increases. Therefore, the direction of sound propagation is bent in the vertical
direction if the temperature is different depending on the altitude.
[0060]
The state of daytime is shown in (a) in the figure. During the daytime when the ground surface is
warmed by solar heat, the lower the altitude, the higher the sound propagation speed, and the
propagation direction of the sound emitted from the outdoor speaker 1 is bent upward. On the
other hand, (b) shows the situation at night. Conversely, the higher the altitude, the faster the
sound propagation speed, and the propagation direction of the sound emitted from the outdoor
speaker 1 is bent downward.
[0061]
For this reason, the controller 22 controls the pointing direction of each of the outdoor speakers
11 to 14 based on the time, and matches the reach area of the broadcast sound to a
predetermined listening area. That is, the directivity direction of the outdoor speakers 11 to 14 is
directed downward at a predetermined time t1 in the morning, and the directivity direction of the
outdoor speakers 11 to 14 is upward at a predetermined time t2 in the evening. Such an
operation is performed on all the outdoor speakers 11 to 14 and is repeated on a daily cycle.
[0062]
According to the present embodiment, the directivity direction of the outdoor speakers 11 to 14
is changed in the vertical direction at a predetermined time. Therefore, it is possible to
compensate for the variation of the listening area based on the temperature change by a simple
03-05-2019
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configuration.
[0063]
In the present embodiment, an example in the case where the pointing direction of the outdoor
speakers 11 to 14 is changed twice a day (time t1, t2) has been described, but the present
invention is not limited to such a case. If it is a one-day cycle, it may be changed three or more
times a day.
[0064]
In the embodiment, although an example in which the temperature near the surface is higher
during the daytime and the temperature higher during the nighttime is described, the present
invention is not limited to such an environment.
That is, even if the temperature does not reverse, the temperature difference near the surface
and the sky can be applied to an environment where daytime and nighttime change.
[0065]
Sixth Embodiment In still another embodiment, in the case of an emergency broadcast signal, the
directivity direction of the outdoor speakers 11 to 14 is directed upward to extend the sound
reachable distance so that the emergency broadcast can surely reach the listening area. You can
also.
[0066]
For example, when the switching signal is transmitted together with the emergency broadcast
signal from the disaster prevention center 23, the controller 22 may change the pointing
directions of all the outdoor speakers 11 to 14 based on the switching signal.
[0067]
As another example, the controller 22 monitors a broadcast signal and determines that it is an
emergency broadcast signal when it includes a predetermined frequency sound or when the
volume is equal to or higher than a predetermined level. The pointing direction of the outdoor
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speakers 11 to 14 may be changed upward.
[0068]
In each of the above embodiments, an example in which the pointing direction of the outdoor
speaker 1 is changed in the vertical direction has been described, but the present invention is not
limited to such a case.
For example, the rotation axis 6 may be disposed vertically, and the pointing direction of the
outdoor speaker 1 may be changed horizontally.
[0069]
Further, in the above embodiment, when the controller 22 instructs the outdoor speakers 11 to
14 to indicate the pointing direction, one of the directions corresponding to each stationary state
of the pointing plate 5 is selected and indicated. The middle of each stationary state can also be
selected as the pointing direction.
For example, if the same message is broadcast repeatedly, the pointing plate 5 is reciprocated
between two stationary states, and if the stationary states are different for each message, the
middle of each stationary state is designated as the pointing direction. Becomes possible.
[0070]
Specifically, if three of the up position, the normal position, and the down position can be
selected as the stationary state of the pointing plate 5, five, including two intermediate directions
realized by switching adjacent positions. The pointing direction can be indicated. That is, in
addition to the "upward" corresponding to the up position, the "front direction" corresponding to
the normal position, and the "downward" corresponding to the down position, the "slightly
upward direction switching the up position and the normal position alternately" Or “a little
downward” which alternately switches between the normal position and the down position
adjacent to each other.
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[0071]
It is the figure which showed one structural example of the outdoor speaker by Embodiment 1 of
this invention. It is sectional drawing at the time of cut | disconnecting the outdoor speaker 1 of
FIG. 1 by AA cutting line. It is sectional drawing at the time of cut | disconnecting the speaker of
FIG. 1 by BB cut surface. 5 is a diagram showing another configuration example of the outdoor
speaker according to Embodiment 1. FIG. It is sectional drawing which showed an example of the
outdoor speaker by Embodiment 2 of this invention. It is a figure showing an example of the
outdoor speaker by Embodiment 3 of the present invention. It is the schematic which showed an
example of the outdoor sound system by Embodiment 4 of this invention. It is explanatory
drawing which showed typically the relationship between a wind direction and the propagation
direction of a sound. FIG. 8 is an explanatory view showing an example of the operation of the
controller 22. It is explanatory drawing which showed typically the relationship between time
and the propagation direction of a sound.
Explanation of sign
[0072]
1, 11 to 14 Speaker 2 Sounding body 3 Diaphragm 4 Horn 5, 5A to 5C Directional plate 6
Rotating shaft 7A, 7B Plate driver 21 Wind direction meter
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