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JP2007256976

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
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DESCRIPTION JP2007256976
An object of the present invention is to solve the problems associated with the installation of a
sound emitting means such as a speaker, and to appropriately cope with changes in the size and
position of the listening area. An array speaker ASP is provided in the vicinity of a ceiling of a
rear wall surface WL1 of a customer seat SE. In the side wall surfaces WL2 and WL3 of the
acoustic space R, acoustic reflection devices r1 to r6 are provided. Since the acoustic beam is
scattered by the acoustic reflector and reaches the audience at the audience seat, the sound
image is localized at the position of the acoustic reflectors r1 to r6, and the position of the
acoustic reflectors r1 to r6 when viewed from the listener It feels as if there are speakers. That is,
the acoustic reflection devices r1 to r6 play a role as virtual speakers (virtual sound sources).
[Selected figure] Figure 2
Acoustic reflector
[0001]
The present invention relates to a technology for listening to voices and musical tones in an
acoustic space such as a hall or a theater.
[0002]
In an acoustic space such as a hall or a theater, generally, a plurality of speakers are dispersedly
disposed on a wall surface or a ceiling.
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It is for preventing concentration of a sound by emitting simultaneously from these several
speakers. In addition, if sound is emitted only from a specific speaker, it is also possible to
localize a sound image to a specific area. However, since it is necessary to install a number of
speakers according to the size of the acoustic space, in addition to requiring considerable cost, it
also requires complicated operations such as wiring around each speaker. .
[0003]
Patent Documents 1 and 2 disclose an acoustic system using an array speaker in which a
plurality of speaker units are arranged in a predetermined direction. Specifically, an array
speaker is installed on a ceiling or the like, and sound waves emitted from the array speaker are
reflected on a wall surface to localize a sound image (Patent Document 1), or the array speaker is
rotated to be viewed from a listener This system is to localize the sound image in all directions of
360 ° (Patent Document 2). The array speaker can emit a directional sound wave (hereinafter
referred to as an acoustic beam) in a desired direction by appropriately controlling the delay time
of the audio signal supplied to each speaker unit. Therefore, even in the system described in
Patent Document 1, the acoustic beam can be emitted in a plurality of directions only by
installing the array speaker at one place on the ceiling, and the wiring work to the speaker is
significantly reduced. Can. However, on a wall such as a hole, usually only specular reflection can
occur, so the positional relationship between the array speaker and the wall limits the size and
position of the listening area to which the acoustic beam can reach. There's a problem. JP-A-9233591 JP-A-9-233588 JP
[0004]
The present invention has been made in view of such a background, and the purpose thereof is to
eliminate the inconvenience relating to the installation of a sound emitting means such as a
speaker, and to change even if the size and position of the listening area change. To provide
technology that can be flexibly handled.
[0005]
In order to solve the problems described above, the present invention radiates an acoustic beam
towards the acoustic reflection surface according to reflecting means having a variable-diameter
acoustic reflection surface, and a directivity parameter representing the radiation direction or
width of the acoustic beam. An acoustic system comprising: a sound emitting means; and a
control means for changing a radius of curvature of the acoustic reflection surface in accordance
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with a drive parameter that determines the shape of the acoustic reflection surface.
In a preferred embodiment of the present invention, a first storage means for storing a listening
area parameter representing the position or size of a listening area, the driving parameter in
association with each other, and an input means for receiving the listening area parameter The
control means may change the radius of curvature of the acoustic reflection surface according to
the driving parameter stored in the first storage means in association with the listening area
parameter input to the input means. Good. Further, in another preferred aspect of the present
invention, a second storage unit that stores a listening area parameter representing the position
or size of a listening area and the directivity parameter in association with each other, and the
listening area parameter is input Sound emission control for changing the radiation direction or
width of the directional sound wave according to the input means and the directivity parameter
stored in the second storage means in association with the listening area parameter input to the
input means And means may be provided.
[0006]
(1) Principle of Array Speaker Before entering into the details of the embodiment of the present
invention, first, the principle of the array speaker used in this embodiment will be briefly
described. FIG. 1 is a diagram showing an electrical configuration of an array speaker ASP
configured by two speaker units SP1 and SP2. In FIG. 1, the central axes Y1 and Y2 of the
speaker units SP1 and SP2 are parallel to each other, and the cones (diaphragms) of the speaker
units SP1 and SP2 are disposed at the same position in the direction of the central axes Y1 and
Y2 It shall be done. Further, the distance between the central axis Y1 and the central axis Y2 is
"a", and the angle from the central axes Y1 and Y2 to the radiation directions Y11 and Y22
(hereinafter referred to as radiation angle) is "θ". Assuming that the listening area is sufficiently
far, the path difference between the sound wave emitted from the speaker unit SP1 in the
direction of the radiation direction Y11 and the sound wave emitted from the speaker unit SP2 in
the direction of the emission direction Y22 is “a · sin θ It becomes ".
[0007]
The audio signal input from the input terminal Tin is branched into two paths. The audio signal
of one of the paths is supplied to the speaker unit SP1 via the delay circuit DL1, and the audio
signal of the other path is supplied to the speaker unit SP2 via the delay circuit DL2. The audio
signal is a signal indicating various sounds such as human voice and musical instrument
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performance sound. The delay circuits DL1 and DL2 respectively delay the supplied audio signal
by time D1 and D2 (D2 ≧ D1) and output the delayed signal. Therefore, a time difference (D2D1) occurs between the sound wave emitted from the speaker unit SP1 and the sound wave
emitted from the speaker unit SP2.
[0008]
Since there is a path difference between the radiation axis Y11 and the radiation axis Y22 as
described above in addition to the time difference between the two sound waves as described
above, both sound waves depend on the position (hearing point) where each sound wave reaches
in the acoustic space R The phase relationship of is different. For example, at a certain position,
both sound waves are in phase and added, and the volume is doubled. Also, at other positions,
both sound waves have an opposite phase and are offset, and the volume becomes zero.
Therefore, by appropriately controlling the delay amount in each of the delay circuits DL1 and
DL2, it is possible to make the sound waves emitted from the array speaker ASP have the desired
directivity. Of course, the principle is the same even if the number of speaker units is further
increased.
[0009]
Although the number of channels of the audio signal is one in FIG. 1, the number of channels
may be more. Also, after delay processing is performed on the audio signal of each channel with
an appropriate delay amount, the audio signal subjected to the delay processing is added and
emitted from each speaker unit, whereby an acoustic beam for each channel is separately
provided. It is possible to emit in different directions. For example, it is possible to emit different
musical tones as different acoustic beams or to emit speech of different languages and dubbed
speech of movies as different acoustic beams.
[0010]
Next, embodiments of the present invention will be described in detail. (2) Overall Configuration
of Sound System FIG. 2 is a plan view showing the configuration of the sound system according
to the embodiment. The sound space R is a hall where concerts and events are held, and a stage
ST where lectures, performances, singing and the like are performed, and a passenger seat SE
where an appreciator (listener) is located are provided. Near the ceiling of the rear wall WL1 of
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the passenger seat SE, an array speaker ASP is provided. The array speaker ASP is a sound
emitting means for emitting a directional sound wave (acoustic beam). Further, on the side wall
surfaces WL2 and WL3 of the acoustic space R, acoustic reflection devices r1 to r6 are provided.
Each of the acoustic reflectors r1 to r6 has an acoustic reflection surface, and reflects an acoustic
beam emitted from the array speaker ASP toward the inside of the acoustic space R by the
acoustic reflection surface. In FIG. 2, arrows W1 to W6 extending from the position of the array
speaker ASP in the direction of the respective acoustic reflectors r1 to r6 mean acoustic beams.
The dotted lines extending concentrically from the positions of the acoustic reflectors r1 to r6
illustrate how the reflected acoustic beam travels (scatters) while diffusing in the acoustic space
R. In the side wall surfaces WL2 and WL3, on the wall surface portions other than the portions
where the acoustic reflection devices r1 to r6 are provided, an acoustic sound absorber such as a
sound absorption panel is provided for the purpose of preventing flutter echo and the like. .
[0011]
Here, FIG. 3 is a perspective view of the acoustic space R viewed from the position of the rear
wall surface WL1. As shown in FIG. 3, the acoustic reflection devices r1 to r6 are provided at
predetermined heights of the side wall surfaces WL2 and WL3. Since the acoustic beam emitted
by the array speaker ASP is reflected by the acoustic reflectors r1 to r6 and reaches the listener
of the audience seat SE, the sound image is localized at the position of the acoustic reflectors r1
to r6. Become. That is, when viewed from the listener, it feels as if there are speakers at the
positions of the acoustic reflection devices r1 to r6. Also, the acoustic reflection surfaces of the
acoustic reflection devices r1 to r6 are configured to be variable in shape as described later, and
are adjusted to have an appropriate shape according to the change in the position and size of the
listening area Ru. The change in the position of the listening area is, for example, the difference
between the case where the listener is concentrated only in front of the passenger seat SE and
the case where the listener is concentrated only near the center of the visitor seat SE. Further, the
change in the size of the listening area is, for example, the difference between the case where the
listeners are dispersed in almost all of the audience SE and the case where the listeners are
concentrated only in front of the audience SE. Note that the acoustic reflection devices r1 to r6
have almost the same configuration, and therefore, when it is not necessary to distinguish them
from one another, they are collectively referred to as "acoustic reflection devices r". The same
applies to the acoustic beams W1 to W6.
[0012]
FIG. 4 is a block diagram showing the electrical configuration of the array speaker ASP and its
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peripheral devices. The array speaker ASP is composed of eight speaker units SP1 to SP8
arranged in a line in the horizontal direction. The main control unit CU includes a CPU and a
memory m as a storage unit. The audio signal supplied from the main control unit CU to the
input terminal Tin is supplied to the speaker units SP1 to SP8 via the delay circuits DL1 to DL8
and the level control circuits W1 to W8. The delay circuits DL1 to DL8 delay the input audio
signal. The level control circuits W1 to W8 attenuate or amplify the level of the input audio
signal. The operation parameters of the delay circuits DL1 to DL8 and the level control circuits
W1 to W8 are designated by the control signal supplied from the main control unit CU. The user
interface unit UI includes an operation unit including various switches and keys, and a display
unit such as a liquid crystal display. The operator can give various instructions to the main
control unit CU by operating the operation unit while referring to the information displayed on
the display unit.
[0013]
(3) Relationship between Acoustic Reflector and Listening Area FIG. 5 is a plan view showing how
one acoustic reflector r provided on the side wall surface WL reflects the acoustic beam W. As
shown in FIG. In FIG. 5, the acoustic beam W is expressed as a set of 17 sound fluxes, and the
central axis of the acoustic beam W is set as the radiation central axis WO. An acoustic reflection
surface rs (hereinafter simply referred to as a reflection surface rs) of the acoustic reflection
device r has a shape corresponding to a part (solid line portion) of an ellipse E indicated by a
dotted line and a solid line in the drawing. The straight line passing through the focal points F
and F1 of the ellipse coincides with the central axis WO of the acoustic beam W. That is, the
shape (ellipse E) of the reflecting surface rs is symmetrical with respect to the radiation central
axis WO of the acoustic beam W. Of the 17 sound fluxes shown in FIG. 5, the sound flux closer to
the radiation center axis WO is reflected in the direction approaching the array speaker ASP, and
the sound flux further from the radiation center axis WO is reflected in the direction away from
the array speaker ASP Do. In the case of the reflecting surface rs shown in FIG. 5, as described
above, since the reflecting surface rs is symmetrical with respect to the radiation center axis WO,
the acoustic beam reflected by the reflecting surface rs is offset in a specific direction. Instead, it
travels in all directions in the acoustic space R. That is, the acoustic beam W is uniformly diffused
to the acoustic space R by the acoustic reflector r. On the other hand, when the shape of the
reflecting surface rs is not symmetrical with respect to the radiation center axis WO of the
acoustic beam W, the reflected acoustic beam W does not diffuse uniformly in the acoustic space
R, but a specific direction Will be somewhat biased. As described above, there are two types of
shapes of the reflecting surface rs: one that is symmetrical about the radiation central axis WO of
the acoustic beam W, and the other that is not symmetrical. In the case where the acoustic beam
W is desired to be uniformly diffused to the acoustic space R by the acoustic reflector r, it is
desirable to use the reflective surface rs of the former, and if such uniform diffusion is not
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desired, the latter The reflecting surface rs may be used.
[0014]
The acoustic system according to the present embodiment can cause the acoustic beam W
reflected by the acoustic reflection device r to reach the listening area even if the position or size
of the listening area changes. Specifically, (i) the method of coping with the change of the
listening area by changing the width and the radiation direction of the acoustic beam W, and (ii)
changing the shape of the reflecting surface rs of the sound reflecting device r. There is a method
to respond to changes in the listening area.
[0015]
First, the method (i) will be described. In the array speaker ASP, the radiation direction of the
acoustic beam W can be changed or the width of the acoustic beam W can be changed by
controlling the delay amount in each of the speaker units SP1 to SP8. Here, the width of the
acoustic beam means the thickness of the acoustic beam in the direction orthogonal to the
traveling direction (radial direction) of the acoustic beam. That is, reducing the width of the
acoustic beam W corresponds to enhancing the directivity, and increasing the width of the
acoustic beam W corresponds to reducing the directivity. FIGS. 6-8 are diagrams showing that
the radiation direction of the acoustic beam W is changed to correspond to the change in the
position of the listening area. As shown in FIG. 6, when the acoustic beam W is emitted toward
the reflecting surface rp1 relatively close to the array speaker ASP side among the reflecting
surfaces rs, the acoustic beam W is reflected in the direction approaching the array speaker ASP
It will be done. Therefore, the acoustic beam W can be made to reach the listening area LA
located behind the acoustic reflector r. In FIG. 6, “forward” is a direction approaching the stage
ST, and “backward” means a direction away from the stage ST (direction approaching the rear
wall surface WL1) (the same applies in the following description).
[0016]
On the other hand, as shown in FIG. 7, when the acoustic beam W is emitted toward the
reflecting surface rp2 relatively far from the array speaker ASP among the reflecting surfaces rs,
the acoustic beam W is directed in the direction away from the array speaker ASP. It will be
reflected. Therefore, the acoustic beam W can reach the listening area LA located in front of the
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acoustic reflection device r. Then, as shown in FIG. 8, when the acoustic beam W is emitted
toward the reflection surface rp3 located in the middle of the reflection surface rp1 of FIG. 6 and
the reflection surface rp2 of FIG. The position of is also near the middle of the listening area of
FIG. 6 and the listening area of FIG. That is, the acoustic beam W can be made to reach the
listening area LA located approximately to the side of the acoustic reflection device r.
[0017]
Furthermore, as can be understood by comparing FIGS. 5 and 6 described above, if the width wd
of the acoustic beam W is increased even if the positions on the reflective surface rs of the
radiation center axis WO are substantially the same (FIG. In the case, the reflected acoustic beam
W will travel in a wider direction. That is, the diffusion effect of the acoustic beam W due to
reflection is increased, and the listening area LA can be enlarged. Conversely, when the width wd
of the acoustic beam W is reduced (in the case of FIG. 6), the direction in which the acoustic
beam W is reflected is limited to a certain direction, so the listening area LA becomes smaller.
[0018]
In order to realize the above method (i), the main control unit CU corresponds in advance to a
listening area parameter indicating the position and size of the listening area LA and a directivity
parameter indicating the radiation direction or width of the acoustic beam. And stored in the
memory m. The listening area parameter is, for example, an xy coordinate value or the like
representing the outer edge of the listening area when the acoustic space R is viewed from above
as an XY plane. The directivity parameter is, for example, the delay amount in each of the
speaker units SP1 to SP8 such that the acoustic beam W has a desired radiation direction or
width. When the listening area parameter is input, the main control unit CU controls the array
speaker ASP according to the directivity parameter stored in association with the listening area
parameter, and changes the radiation direction or the width of the acoustic beam W.
[0019]
Next, the method of (ii), that is, the method of changing the shape of the reflecting surface rs to
cope with the change of the listening area will be described. As shown in FIG. 9, when the curved
diameter of the reflecting surface rs is relatively large, most of the acoustic beam W is reflected
in the direction away from the array speaker ASP. That is, a reflection phenomenon similar to
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specular reflection that occurs on a planar wall surface is occurring. In this case, as shown in FIG.
9, the acoustic beam W can be made to reach the listening area LA located in front of the
acoustic reflection device r. In FIG. 9 and FIGS. 10 and 11 described later, it is assumed that the
shape of the reflecting surface rs is not symmetrical with respect to the radiation central axis WO
of the acoustic beam W. Next, as shown in FIG. 10, when the radius of curvature of the reflecting
surface rs is smaller than in the case of FIG. 9, the direction of the acoustic beam W to be
reflected is less biased. That is, as viewed from the position of the acoustic reflection device r, the
acoustic beam can reach a relatively wide listening area LA from the front to the rear. Further, as
shown in FIG. 11, when the curved diameter of the reflecting surface rs is further reduced, the
acoustic beam W is reflected in the direction approaching the array speaker ASP. Therefore, the
acoustic beam W can reach the listening area LA located behind the acoustic reflection device r.
[0020]
In order to realize the method (ii) as described above, the main control unit CU stores the abovementioned listening area parameter and the drive parameter for determining the shape of the
reflecting surface rs in advance in the memory m. The contents of the drive parameters will be
specifically described later, but may be parameters given to various drive means in order to
change the shape of the reflecting surface rs. When the listening area parameter is input, the
main control unit CU changes the shape of the reflecting surface rs in accordance with the
driving parameter stored in association with the listening area parameter.
[0021]
The above is the contents of methods (i) and (ii). 6 to 11 used in the description represent an
example of the state of reflection. Actually, while changing the radiation direction or width of the
acoustic beam W in accordance with the position and size of the listening area LA, the radiation
direction or width and the shape of the reflection surface are changed, for example, the shape of
the reflection surface rs is changed. It may be changed simultaneously to cope with the change of
the listening area LA.
[0022]
(4) Configuration of Acoustic Reflection Device Next, the configuration of the acoustic reflection
device r will be described by giving some specific examples. The acoustic reflector r shown in
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FIG. 12 incorporates a plurality of bag-like members inside the reflective surface rs, and adjusts
the amount of gas injected into each bag-like member to change the shape of the reflective
surface rs It is something that The reflecting surface rs is formed of an elastic material, and its
end is fixed to the side wall surface WL by bonding or a predetermined fixture. Inside the
reflective surface rs, a plurality of elastic bag members 22a to 22e are provided. Valves 23a-23e
are provided at the open ends of the bag-like members 22a-22e, respectively, and are connected
to the pipe 24 via these valves 23a-23e. The pipe 24 is connected to the pump 25, and a gas
such as air is supplied from the pump 25 to the bag-like members 22 a to 22 e through the pipe
24. The pipe 24 and the pump 25 are injection mechanisms for injecting a gas into each of the
sac-like members 22a to 22e. Further, the main control unit CU and the valves 23a to 23e play a
role of adjusting the amount of gas injected into each of the bag-like members 22a to 22e.
[0023]
More specifically, the main control unit CU calculates the optimum shape of the reflection
surface rs from the relationship between the position of the acoustic reflection device r and the
position and size of the listening area LA, and the gas has such a shape. Determine the injection
volume. Then, the main control unit CU outputs drive parameters specifying the drive time of the
pump 25 and the opening / closing timing of each of the valves 23a to 23e to the pump 25 and
the valves 23a to 23e. Thus, the shape of the reflective surface rs can be changed to a desired
shape by adjusting the amount of gas injected into each of the bag-like members 22a to 22e. For
example, as shown in FIG. 12, when the reflecting surface rs is formed to lie generally in the
direction to the left in the figure, a relatively large amount of gas is injected into the bag-like
members 22a and 22b on the right in the figure. A relatively small amount of gas may be injected
into the left bag-like members 22d and 22e. In this way, since the bag-like members 22d and 22e
are shaped so as to be crushed by pressure from the bag-like members 22a and 22b, it is
possible to make the entire reflecting surface rs lie on the left side It becomes.
[0024]
Next, an acoustic reflection device r shown in FIG. 13 changes the shape of the reflection surface
rs by injection of a gas as in FIG. 12, but has a simpler structure than that of FIG. The reflecting
surface rs is formed of an elastic material, and its end is fixed to the side wall surface WL by
adhesion or by a predetermined fixture. A hole 31 opened in the side wall surface WL is provided
with a valve 31 and is connected to the pipe 32 via the valve 31. The pipe 32 is connected to the
pump 33, and a gas such as air is supplied from the pump 33 to the inside of the reflective
surface rs through the pipe 32. The pipe 32 and the pump 33 are injection mechanisms for
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injecting a gas into the reflective surface rs. Further, the main control unit CU and the valve 31
play a role of adjusting the amount of gas to be injected. More specifically, the main control unit
CU calculates the optimum shape of the reflection surface rs from the relationship between the
position of the acoustic reflection device r and the position and size of the listening area LA, and
the gas has such a shape. Determine the injection volume. Then, the main control unit CU outputs
drive parameters specifying the drive time of the pump 33 and the opening / closing timing of
the valve 31 to the pump 33 and the valve 31. For example, if the injection amount of gas is
reduced, the shape of the reflecting surface rs becomes a curved shape having a relatively large
curved diameter as shown by the solid line in FIG. On the other hand, if the injection amount of
gas is increased, the shape of the reflecting surface rs becomes a curved shape having a relatively
small curved diameter, as shown by the dotted line in FIG.
[0025]
Next, an acoustic reflection device r shown in FIG. 14 changes the shape of the reflection surface
rs by applying a force to the reflection surface rs formed of a flexible material to bend the
reflection surface rs. In FIG. 14, one end of the reflective surface rs is fixed to the side wall
surface WL. Further, the other end is fixed to a movable member 42 movable in the arrow X
direction along the guide rail 41. The moving member 42 is fixed at an arbitrary position on the
guide rail 41 by the drive of the motor 43. The guide rail 41, the moving member 42, and the
motor 43 are drive mechanisms that cause the reflecting surface rs to bend. Then, the main
control unit CU plays a role of adjusting the deflection amount. More specifically, the main
control unit CU calculates the optimal shape of the reflective surface rs from the relationship
between the position of the acoustic reflector r and the position and size of the listening area LA,
and moves so as to be that shape The position of the member 42 is determined. Then, the main
control unit CU outputs a drive parameter for specifying a drive time to the motor 43. For
example, when the moving member 42 is moved to the left in the drawing, the shape of the
reflecting surface rs becomes a curved shape having a relatively small curved diameter, as shown
by the solid line in FIG. On the other hand, when the moving member 42 is moved to the right in
the figure, the shape of the reflecting surface rs becomes a curved shape having a relatively large
curved diameter as shown by the dotted line in FIG.
[0026]
(5) Operation Example Next, a specific operation example will be described. FIG. 15 and FIG. 16
are diagrams showing an example of the screen displayed on the display unit of the user
interface unit UI. In the case of the designated seat system, the operator can grasp in advance
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information (in other words, information corresponding to the above-described listening area
parameter) as to which seat the listener is present. The listening area parameter may be input.
That is, the user interface unit UI functions as an input unit to which a listening area parameter is
input. The main control unit CU causes the display unit to display the status of the seated /
vacant seat according to the content of the input listening area parameter. In FIGS. 15 and 16,
when “o” is described in each square (seat), it means that there is a listener in that seat, and
nothing is described Means that there are no listeners in that seat (that is, it is an empty seat).
For example, FIG. 15 shows a state in which a listener is present in almost the entire area of the
passenger seat SE. Therefore, the listening area LA in this case is a hatched area. When the
listening area LA has a position and a size as shown in FIG. 15, it is preferable that the acoustic
beam W is reflected from each of the acoustic reflectors r1 to r6 as shown in FIG. In addition, in
order to avoid that a drawing becomes complicated, illustration of the acoustic beam reflected by
acoustic reflection apparatus r1-r3 is abbreviate | omitted.
[0027]
Therefore, for example, as shown in FIG. 7 or 9 described above, the acoustic reflection device r4
reflects the acoustic beam W in a direction away from the array speaker ASP and toward a
relatively wide area. In this case, the above-mentioned reflection phenomenon may be realized by
changing the radiation direction or width of the acoustic beam W, or the above-mentioned
reflection phenomenon may be realized by changing the shape of the reflecting surface rs. . Also,
as shown in FIG. 8 or 10 described above, the acoustic reflection device r5 reflects the acoustic
beam W to the side of the self and toward a relatively wide area. Also in this case, the radiation
direction or width of the acoustic beam W may be changed, or the shape of the reflecting surface
rs may be changed. Then, as shown in FIG. 6 or 11 described above, the acoustic reflection device
r6 reflects the acoustic beam toward the relatively wide area in the direction approaching the
array speaker ASP. Of course, also in this case, the radiation direction or width of the acoustic
beam W may be changed, or the shape of the reflecting surface rs may be changed.
[0028]
With respect to the example of FIG. 15, FIG. 16 shows the case where a listener is present only in
the front part of the passenger seat SE. When the listening area LA has a position and a size as
shown in FIG. 16, it is preferable that the acoustic beam W is reflected from each of the acoustic
reflectors r1 to r6 as shown in FIG. Also in FIG. 18, for the same reason as in FIG. 17, illustration
of the acoustic beam reflected by the acoustic reflectors r1 to r3 is omitted.
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[0029]
Therefore, for example, as shown in FIG. 7 or 9 described above, the acoustic reflectors r4 and r5
reflect the acoustic beam W in a direction away from the array speaker ASP and toward a
relatively narrow area. Further, as shown in FIG. 8 or 10 described above, the acoustic reflection
device r6 reflects the acoustic beam in a direction approaching the array speaker ASP and
toward a relatively narrow area. Any of the acoustic reflectors r4 to r6 may realize the above
reflection phenomenon by changing the radiation direction or the width of the acoustic beam W,
or may change the shape of the reflecting surface rs as described above. A reflection
phenomenon may be realized.
[0030]
According to the embodiment described above, since the listener hears the sound reflected from
the acoustic reflection devices r1 to r6, the listener feels as if there are speakers at the positions
of the acoustic reflection devices r1 to r6. It will be. That is, the acoustic reflectors r1 to r6 play a
role as a so-called virtual speaker (virtual sound source). In this way, since it is not necessary to
distribute a plurality of speakers on the ceiling or wall of the acoustic space, it is possible to omit
the wiring operation to the conventional speakers. Further, by changing the width and the
radiation direction of the acoustic beam W and the shape of the reflecting surface rs, it is
possible to flexibly cope with changes in the position and size of the listening area. Also, since the
acoustic beam after reaching the listener is absorbed by the acoustic absorbers of the side walls
WL2, WL3, there is no need to be concerned about the problems caused by further re-reflections.
[0031]
The embodiment described above can be modified as follows. The acoustic space to which the
acoustic system according to the embodiment is applied can be applied to any facility indoors or
outdoors, for example, a church, an opera house, a conference room, or a competition venue such
as synchronized swimming or figure skating. is there. In the case of outdoor application, an array
speaker or acoustic reflection device may be installed on a dedicated pole or column. Also, it may
be hung on the ceiling or installed on balloons floating in the air. In the embodiment, an array
speaker having a single-row configuration has been described. However, the present invention is
not limited to this. For example, an array speaker may be configured by a total of m × n speaker
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units, with m speaker units having an n-row configuration. Good. When only the reflection
surface of the acoustic reflection device is changed to cope with the change in the listening area,
it is not necessary to use the array speaker, and it is directed to emit a directional sound wave
toward the acoustic reflection surface. If it is a sex speaker, it can be substituted.
[0032]
The acoustic reflection device is not limited to the one described in the embodiment, as long as
the shape of the acoustic reflection surface is variable. FIGS. 19 to 21 show an apparatus of a
type in which the overall shape as an acoustic reflection surface is changed by changing the
orientations of a plurality of members each having a reflection surface. The acoustic reflection
device r includes a plurality of curved plate members (four plate members f1 to f4 in FIGS. 19 to
21) and a motor 51. One end of each of the plate members f1 to f4 is rotatably attached to the
wall surface WL. When the main control unit CU gives a drive parameter to the motor 51 and
drives it, the plate members f1 to f4 rotate around one end near the wall surface WL. That is, the
motor 51 is a drive mechanism for bending the plate member, and the main control unit CU has a
role of adjusting the amount of bending. As shown in FIG. 19, when the plate members f1 to f4
rise from the wall surface WL, most of the acoustic beam W is reflected in the direction
approaching the array speaker ASP. Therefore, the acoustic beam W can be made to reach the
listening area LA located behind the acoustic reflector r. On the other hand, as shown in FIG. 20,
when the plate members f1 to f4 lie in the direction of the wall surface WL (when the plate
members f1 to f4 are approaching the wall surface WL), most of the acoustic beam W is an array
Reflect in the direction away from the speaker ASP. That is, a reflection phenomenon similar to
specular reflection that occurs on a planar wall surface is occurring. In this case, the acoustic
beam W can reach the listening area LA located in front of the acoustic reflector r. Then, as
shown in FIG. 21, when the direction of the plate members f1 to f4 is about halfway between FIG.
19 and FIG. 20, the direction of the acoustic beam W to be reflected does not have much
deviation. That is, the acoustic beam can reach the listening area LA located to the side of the
acoustic reflection device r. When the change in the listening area is dealt with by changing only
the radiation direction or the width of the acoustic beam, it is not necessary to make the shape of
the acoustic reflection surface variable.
[0033]
The acoustic reflection surface of the acoustic reflection device is not limited to the convex
surface described in the embodiment, and may be a concave surface. The convex acoustic
reflection surface is a shape in which the central part of the reflection surface is projected to the
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array speaker than the end of the reflection surface, and the concave acoustic reflection surface
is the center part of the reflection surface is an end of the reflection surface The shape is more
indented to the array speaker than the part. When the acoustic beam W is reflected by the
convex acoustic reflection surface, the reflected acoustic beam W travels while diffusing in the
acoustic space. Conversely, when the acoustic beam W is reflected by a concave acoustic
reflection surface, the acoustic beam W travels in the acoustic space while converging. A concave
acoustical reflective surface is useful when the listening area is very narrow.
[0034]
Further, one acoustic reflection surface may be configured by a concave surface and a convex
surface. For example, as shown in FIG. 22, on a curved surface (convex surface) having a
relatively large radius of curvature rm, a convex portion or a recess having a diameter smaller
than the radius of curvature is formed. Generally, as the radius of curvature of the curved surface
is larger, sound waves in the low frequency range are reflected, and as the radius of curvature of
the curved surface is smaller, sound waves in the high frequency range are reflected.
Accordingly, the sound wave in the low to mid range is mainly reflected on the entire curved
surface of the curved diameter rm, and the sound wave in the high range is mainly reflected on
the small convex or concave portion. Further, as shown in FIG. 22, assuming that the crosssectional shape of the acoustic reflection surface is a third-order circle in which the radius of
curvature rm changes gradually, sound waves in the low frequency range are reflected on the
curved surface with a larger radius of curvature rm. In a curved surface with a smaller radius of
curvature rm, the sound wave in the midrange will be reflected. Therefore, the shape of the
acoustic reflection surface may be designed in accordance with the principle as described above,
depending on which band of the sound wave is desired to be mainly reflected. In addition, the
shape of the acoustic reflection surface is not limited to an ellipse, and may be a hyperbola or a
parabola. Furthermore, the acoustic reflection surface is not limited to the vertically extending
columnar shape illustrated in FIG. 3, and may be, for example, a hemispherical shape. The use of
a hemispherical acoustic reflection surface makes it easy to reflect the acoustic beam W
downward of the acoustic reflection device.
[0035]
In the embodiment described above, when the listening area is input to the user interface unit UI,
the radiation direction or width of the acoustic beam, or the acoustic, according to the directivity
parameter or driving parameter stored in association with the listening area parameter. The
shape of the reflective surface was changed. However, the present invention is not limited to this,
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and the operator may directly input the directivity parameter or the drive parameter to the user
interface unit UI. In this case, it is desirable to determine appropriate directivity or drive
parameters while actually listening to the reflected acoustic beam in the acoustic space.
[0036]
It is a figure explaining the principle for an array speaker to emit a directional sound wave. It is a
schematic diagram which shows the whole structure of the sound system which concerns on one
Embodiment of this invention. It is a perspective view which shows the acoustic space to which
the acoustic system which concerns on the embodiment is applied. It is a block diagram which
shows the electrical configuration of the array speaker and its peripheral device in the same
system. It is a figure which shows a mode that an acoustic beam is reflected by the acoustic
reflective surface. It is a figure which shows the relationship between an acoustic reflection
apparatus and a listening area. It is a figure which shows the relationship between an acoustic
reflection apparatus and a listening area. It is a figure which shows the relationship between an
acoustic reflection apparatus and a listening area. It is a figure which shows the relationship
between an acoustic reflection apparatus and a listening area. It is a figure which shows the
relationship between an acoustic reflection apparatus and a listening area. It is a figure which
shows the relationship between an acoustic reflection apparatus and a listening area. It is a figure
which shows the structure of an acoustic reflection apparatus. It is a figure which shows the
structure of an acoustic reflection apparatus. It is a figure which shows the structure of an
acoustic reflection apparatus. It is a figure which illustrates the screen displayed on the display
part of a user interface part. It is a figure which illustrates the screen displayed on the display
part of a user interface part. It is a figure which shows the range which the acoustic beam
reflected by each acoustic reflector reaches. It is a figure which shows the range which the
acoustic beam reflected by each acoustic reflector reaches. It is a figure which shows the
relationship between the acoustic reflection apparatus in a modification, and a listening area. It is
a figure which shows the relationship between the acoustic reflection apparatus in a
modification, and a listening area. It is a figure which shows the relationship between the
acoustic reflection apparatus in a modification, and a listening area. It is a figure which shows the
cross-sectional shape of the reflective surface of the acoustic reflection apparatus in a
modification.
Explanation of sign
[0037]
R: acoustic space, ASP: array speaker, SP1 to SP8: speaker unit, W1 to W8: level control circuit,
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DL1 to DL8: delay circuit, CU: main control unit, UI: user interface unit, r1 to r6: acoustic
reflection device, W1 to W6: acoustic beam, rs: acoustic reflection surface, LA: listening area.
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