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JP2010068512

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2010068512
PROBLEM TO BE SOLVED: To provide a directional sound generator and a directional speaker
array provided with the same. A directional sound generator for concentrating and outputting
sound only in a specific area and a directional speaker array including the same are disclosed. A
directional acoustic generator according to an embodiment of the present invention includes an
acoustic transducer that outputs sound waves of opposite phase to each other in front and back,
and a reflecting plate positioned behind the acoustic transducer, and a front portion of the
acoustic transducer And the back part are separated, and it is comprised so that it may include
the shielding board which increases the interference distance of the front radiation sound and
back radiation sound from an acoustic transducer. Thereby, the directivity of sound can be
improved while having a uniform sound pressure level in the entire frequency range. 【Selection
diagram】
Directional sound generator and directional speaker array having the same
[0001]
The present invention relates to directional sound generation technology, and more particularly,
to a directional sound generator for concentrating and outputting sound only in a personal sound
zone and a directional speaker array including the same.
[0002]
Since the sound generator such as a general loudspeaker has no directivity at the sound output,
the radiation sound from the sound generator spreads uniformly over the whole area.
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1
That is, although the sound pressure level may change somewhat depending on the position of
the listener, the sound spreads widely around the sound generator. Therefore, since the sound is
transmitted unilaterally to a person who does not want to listen, it causes stuttering damage. Of
course, headphones and earphones are useful because they can transmit sound only to specific
listeners, but they are inconvenient when worn and not good for hearing health.
[0003]
As a result, techniques for transmitting sound only to a specific listener or a personal sound zone
have been studied without a separate device such as an earphone or a headset. As an example,
technology to improve directivity by arranging a large number of sound sources that output
sounds of different phases in a row to improve the directivity of the emitted sound, or by
installing a rigid wall behind the sound sources Is disclosed.
[0004]
However, in such a method, the distortion of the sound is severe due to the frequency domain,
and in order to obtain constant directivity performance over the entire frequency domain, the
signal property is additionally compensated according to the frequency property or the volume
of the sound generator Can be large.
[0005]
According to one aspect of the present invention, a directional sound generator having a simpler
structure and a directional speaker array provided with the directional sound generator are
provided.
[0006]
A directional acoustic generator according to one aspect of the present invention comprises an
acoustic transducer that outputs sound waves of opposite phase to each other forward and
backward, a reflecting plate positioned behind the acoustic transducer, and a front portion of the
acoustic transducer. And a back plate to separate the back surface from each other and to
increase the interference distance between the front emission sound and the back emission
sound from the acoustic transducer.
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[0007]
The directional sound generator is connected to the reflection plate, and is formed to cover upper
and lower sides of the acoustic transducer, and is configured to block the directivity of the sound
wave output from the acoustic transducer in the vertical direction. It may further include a board.
A sound absorbing material may be further attached to the reflection plate or the first blocking
plate.
[0008]
Further, according to another aspect of the present invention, there is provided a directional
speaker array comprising: an acoustic transducer for outputting sound waves of opposite phase
to each other forward and backward; a reflector positioned behind the acoustic transducer; A
plurality of directional acoustic generating parts including: a first blocking plate separating the
front part and the back part and increasing the interference distance between the front radiation
sound and the back radiation sound from the acoustic transducer; and the directivity A preprocessing unit that separates and compensates for the low frequency component and the high
frequency component of the sound wave output through the sound generation unit; and a control
unit that supplies the preprocessed signal to the multiple directional sound generation units
Including.
[0009]
According to one embodiment of the present invention, it is possible to improve the directivity of
sound while having a uniform sound pressure level in the entire frequency range.
In particular, high directivity can be obtained without increasing the array size in the low
frequency area where a long array size is required, and the influence on others located outside
the specific sound area can be minimized.
[0010]
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3
And while adopting a simple structure, the effective distance in front of and behind the acoustic
transducer can be increased to obtain high radiation efficiency.
In addition, by removing the directivity in the vertical direction while maintaining the directivity
in the horizontal direction, a certain directivity performance can be obtained regardless of the
height or posture of the listener or the installation position of the directional sound generator.
[0011]
In the case of additionally attaching a sound absorbing material, it is possible to improve the nonuniform directivity and frequency response that can be generated in the high frequency region,
and to use the directivity generator usable in all frequency bands in one array structure It can be
configured.
In addition, the distortion of the sound can be reduced by separating the low frequency region
and the high frequency region and performing other pre-processing separately for each band.
[0012]
FIG. 1 is a side view of a directional sound generator according to an embodiment of the present
invention. It is a side view at the time of equipping the directional sound generator of FIG. 1 with
a sound absorbing material further. FIG. 1 is a front view and a perspective view of a directional
sound generator according to an embodiment of the present invention. FIG. 1 is a front view and
a perspective view of a directional sound generator according to an embodiment of the present
invention. FIG. 7 is a side view of a directional sound generator according to another embodiment
of the present invention. It is a side view of a directional sound generator in the case of further
equiping a directional sound generator with a baffle and a loop with a sound absorbing material.
5 is an example showing a sound zone in a directional sound generator according to an
embodiment of the present invention. FIG. 6 shows various forms of an enclosure of the
directional sound generator of the present invention. FIG. 6 shows various forms of an enclosure
of the directional sound generator of the present invention. FIG. 6 shows various forms of an
enclosure of the directional sound generator of the present invention. It is the graph which
showed the frequency response characteristic of the low frequency domain at the time of using a
baffle plate and a loop, and the frequency response characteristic at the time of using a sound
absorbing material in a high frequency domain. It is the graph which showed the frequency
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response characteristic of the directional sound generator further provided with the preprocessing part. FIG. 5 is a block diagram of a directional speaker array according to an
embodiment of the present invention. FIG. 11 is a detailed block diagram of the directional
speaker array of FIG. 10; FIG. 1 is a perspective view of a directional speaker array according to
an embodiment of the present invention.
[0013]
The present invention will now be described more fully with reference to the accompanying
drawings, in which exemplary embodiments of the invention are shown.
[0014]
FIG. 1 is a side view of a directional sound generator according to an embodiment of the present
invention.
The acoustic transducer 110 is a device that generates sound like a loudspeaker. The sound
output from the acoustic transducer 110 can be emitted forward or backward. That is, the
acoustic transducer 110 outputs sounds in antiphase with each other in the forward and
backward directions.
[0015]
Behind the acoustic transducer 110, a reflector 130 is present to reflect the sound emitted to the
rear of the acoustic transducer 110.
[0016]
As a first blocking plate, the baffle 120 separates the front and back of the acoustic transducer
110 and increases the interference distance between the front and back radiation from the
acoustic transducer 110.
In other words, the sound pressure level of the radiated sound depends on the wavelength of the
sound and the distance d1 between the acoustic transducer 110 and the reflector 130 and the
interference length between the front and back radiation of the acoustic transducer 110 Affected
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by d2. That is, although d1 and d2 must maintain a constant distance, particularly in the low
frequency region, the wavelength of sound becomes long, so d1 and d2 must also be large. Thus,
if the acoustic transducer 110 is used in an open state without the baffle 120 installed, d1 must
be increased, and the acoustic generator, i.e., the directional speaker enclosure, becomes large. At
this time, the baffle 120 generates destructive interference between the front radiation sound
and the back radiation sound at the acoustic transducer 110, and virtually assumes the distance
d2 that the sound wave must travel to have directivity of the sound. In the low frequency region,
high radiation efficiency can be obtained.
[0017]
FIG. 2 is a side view of the directional sound generator of FIG. 1 further provided with a sound
absorbing material. Referring to FIG. 2, a sound absorbing material 210 is attached to the front
surface of the reflecting plate 130 or the back surface of the baffle 120 to absorb high frequency
components of the sound output from the acoustic transducer 110. When a simple rigid body is
used as the reflector 130 in the high frequency region or a rigid baffle surface is used as it is,
interference phenomena occur in a complicated form in the high frequency region of sound.
Complex forms of interference in the high frequency region are described below with reference
to FIG.
[0018]
On the other hand, in the high frequency region, sufficient directivity can be obtained without a
separate component such as the reflector 130 for obtaining directivity. Therefore, it is desirable
to reduce the interference effect in the reflecting plate 130 and the baffle 120 by attaching the
sound absorbing material 210 and absorbing the components in the high frequency region.
[0019]
3A and 3B are a front view and a perspective view of a directional sound generator according to
an embodiment of the present invention. Referring to FIGS. 1, 3A and 3B, the baffle 120 is
formed in a plate shape, and is formed in a direction parallel to the traveling direction of the
sound wave output from the acoustic transducer 110. It can be seen that it is formed narrower
than the top and bottom and left and right widths to separate the front and back of the acoustic
transducer 110. The size of the baffle 120 may vary depending on the enclosure size and
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frequency characteristics of the directional sound generator. More specifically, if the size of the
baffle 120 is similar to or larger than the wavelength of the sound, a complex interference
pattern is generated, so the width of the baffle 120 is the wavelength at the highest frequency of
the low frequency region of the sound. It is desirable to be designed smaller than that.
[0020]
FIG. 4 is a side view of a directional sound generator according to another embodiment of the
present invention. Referring to FIG. 4, it can be seen that the directional sound generator of FIG.
1 further comprises a loop 410 as a second blocking plate. The reflector 130 should ideally have
an infinite size to maximize the reflection effect or be very large compared to the wavelength.
However, since infinite size reflectors are not possible, in order to obtain the desired
performance regardless of the installation position of the directional sound generator, the
reflector 130 can obtain directivity while having a finite size. There must be.
[0021]
However, generally in the formation of a specific sound area by directivity, it is necessary to
generate a change in sound pressure due to horizontal movement. In other words, there is no
change in sound pressure level depending on the change in distance in the vertical direction, for
example, height or posture such as the height or posture of the listener, and the change in sound
pressure level is generated by the change in distance in the lateral direction. A region must be
formed.
[0022]
For this purpose, the upper and lower portions are closed so that the destructive interference
does not occur in the upper and lower directions, and the open loop 410 is further provided in
the left and right directions. That is, the loop 410 is connected to the reflector 130 and formed to
cover the upper and lower sides of the acoustic transducer 110 to reduce the directivity of the
sound wave output from the acoustic transducer 110 in the vertical direction. Through this, the
size of the back reflector 130 and the volume of the acoustic transducer 110 can be reduced.
Also, the radiation sound pressure level is increased by preventing the destructive interference in
the vertical direction.
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[0023]
On the other hand, the loop 410 can be designed to block or partially block the whole between
the reflector 130 and the acoustic transducer 110. Various forms of loop 410 are described
below with reference to FIGS. 7A-7C.
[0024]
FIG. 5 is a side view of the directional sound generator when the directional sound generator
having the baffle and the loop is further provided with the sound absorbing material 210.
Referring to FIG. 5, as described above with reference to FIG. 2, by further including the sound
absorbing material 210 to absorb the high frequency component, it is possible to prevent the
complicated form interference phenomenon occurring in the high frequency section. I
understand.
[0025]
FIG. 6 is an example showing a sound zone in a directional sound generator according to an
embodiment of the present invention.
[0026]
By using the directional sound generator 600 having the baffle 120, the reflector 130 and the
loop 410, the directivity in the left and right direction can be added and the directivity in the
vertical direction can be decreased, and the specific sound area as shown in FIG. 610 can be
formed.
As a result, regardless of the installation height of the directional sound generator 600 or the
height and posture of the listener, it is possible to form a sound area of a certain area.
[0027]
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8
7A to 7C show various forms of the enclosure of the directional sound generator of the present
invention. Referring to FIGS. 7A to 7C, it can be appreciated that the configurations of the baffles
120 and the loops 410 can be variously embodied. FIG. 7A is an example of a directional sound
generator enclosure when only the baffle 120 is provided without the loop 410, and FIGS. 7B and
7C are examples of the acoustic generator enclosure when the loop 410 is further provided. It is
an example.
[0028]
Meanwhile, the loop 410 may be embodied to block a part between the reflector 130 and the
acoustic transducer 110 as shown in FIG. 7B, and as shown in FIG. It may be embodied to shut
off.
[0029]
FIG. 8 is a graph showing the frequency response characteristic in the low frequency region
when the baffle plate and the loop are used and the frequency response characteristic when the
sound absorbing material is used in the high frequency region.
Referring to FIG. 8, it can be understood that the complex interference phenomenon in the high
frequency region can be eliminated by absorbing the component in the high frequency region
through the sound absorbing material 210. That is, as described above, in the high frequency
region, sufficient directivity can be obtained even without the additional component for obtaining
directivity, and the sound absorbing material 210 is attached to attach the reflection plate 130 or
the baffle 120. It is desirable to reduce the interference effects.
[0030]
More specifically, in the low frequency region, the sound pressure is increased by providing the
baffle 120 and the loop 410, and in the high frequency region, the fluctuation of the sound
pressure is reduced due to the influence of the sound absorbing material 210. That is, the
increase in sound pressure in the low frequency region is not the effect of the attachment of the
sound absorbing material 210 but the effect of attachment of the baffle 120 and the loop 410,
and the sound pressure characteristic equalization in the high frequency region is the sound
absorbing material 210. Is the effect of adhesion.
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[0031]
FIG. 9 is a graph showing the frequency response characteristic of the directional sound
generator further including a preprocessing unit.
[0032]
The directional sound generator according to an embodiment of the present invention exhibits
different response characteristics between the low frequency region and the high frequency
region.
More specifically, in the low frequency region, the response characteristic is uniform, but the
sound pressure level linearly changes in the form that the lower the frequency is, the higher the
sound pressure level is in the high frequency region. , Frequency response characteristics are
uneven.
[0033]
Therefore, the system further comprises a pre-processing unit that separates the low frequency
component and the high frequency component of the sound output from the acoustic transducer
with reference to the frequency response characteristic of the acoustic transducer and linearly
corrects or compensates. Can.
[0034]
The pre-processing unit linearly corrects the response characteristic in the low frequency region
and corrects the non-uniform response characteristic in the high frequency region.
For this purpose, low frequency pass filters (LPFs) and high frequency pass filters (HPFs) are
used to separate the frequency regions, and amplification filters and inverse filters (frequency
filters). Separately process the acoustic signal separately.
[0035]
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10
Referring to FIG. 9, it can be seen that after the low frequency pass filter is used to separate the
low frequency range acoustic signal, the linear variation is corrected to improve the response
characteristic. At this time, the correction in the low frequency region is not a collective simple
amplification, but the amplification level is corrected differently for each frequency. Then, after
separating the high frequency components using the high frequency pass filter, it can be seen
that the response characteristics of the high frequency components are improved using the
inverse filter having the characteristic opposite to the non-uniform response characteristic. On
the other hand, in order to measure in advance the response characteristics of the low frequency
region and the high frequency region, it is possible to select a filter with reference to the
response characteristics.
[0036]
FIG. 10 is a block diagram of a directional speaker array according to an embodiment of the
present invention.
[0037]
An array can be implemented using a plurality of directional sound generators as described
above.
That is, if several directional sound generators are used, directivity can be improved and
radiation efficiency can be improved.
[0038]
Referring to FIG. 10, the directional speaker array includes a pre-processing unit 1010, a control
unit 1020, and a sound generation unit 1030. The sound generator 1030 is a directional sound
generator as described above with reference to FIGS. 1 to 9. The preprocessing unit 1010
corrects the response characteristics for each frequency band in the low frequency region and
compensates for the non-uniform response characteristics in the high frequency region. For this
purpose, low frequency pass filters and inverse filters are used to separate and process acoustic
signals according to frequency domain. The control unit 1020 controls supply of the acoustic
signal processed by the preprocessing unit 1010 to the acoustic generation unit 1030. That is,
the acoustic signals separated and corrected or compensated for each frequency domain are
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processed and supplied to the respective sound generation units 1030.
[0039]
11 is a detailed block diagram of the directional speaker array of FIG. The preprocessing unit
1110 includes a low frequency pass filter (LPF) 1111, a high frequency pass filter (HPF) 1112, a
compensation unit 1113, and an inverse filter 1114. The acoustic signal input to the preprocessing unit 1110 is separated in the low frequency region by the low frequency pass filter
1111 and amplified separately for each frequency band by the compensation unit 1113. The
signals in the high frequency region are separated by a high frequency pass filter 1112 and
compensated by an inverse filter 1114. The inverse filter 1114 is a filter having a response
characteristic that is opposite to the high frequency response characteristic of the directional
sound generator 1130. Thereby, high frequency response characteristics can be compensated
uniformly.
[0040]
The control unit 1120 includes a low frequency region processing unit 1121, a high frequency
region processing unit 1122, and a summing unit 1123. The low frequency region processing
unit 1121 and the high frequency region processing unit 1122 generate and output the acoustic
signal supplied to each sound generation unit 1130 according to the number of the sound
generation units 1130, and the summing unit 1123 is divided into frequency regions. The
combined acoustic signals are supplied to the respective acoustic generators 1130.
[0041]
FIG. 12 is a perspective view of a directional speaker array according to an embodiment of the
present invention. Respective reflectors provided in a large number of directional sound
generation units can be shared with each other, and as shown in FIG. 12, may be configured in
one dimension or may be embodied in two dimensions. is there. In addition, the intervals of the
directional sound generators may be equal to or different from each other. The baffles may be
integrally formed, and then may be embodied in a form in which slits are formed between the
baffles. The width of the slits may also vary depending on the spacing of the directional sound
generators.
08-05-2019
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[0042]
The above description has focused on the preferred embodiments of the present invention. Those
skilled in the art will appreciate that the present invention can be embodied as a modified form
without departing from the essential characteristics of the present invention. Thus, the disclosed
embodiments are to be considered in an illustrative rather than a restrictive sense. The scope of
the present invention is expressed in the claims, and any difference that falls within the
equivalent scope should be analyzed as included in the present invention.
[0043]
The present invention is applicable to the technical field of a directional sound generator and a
directional speaker array including the same.
[0044]
DESCRIPTION OF SYMBOLS 110 acoustic transducer 130 reflector 120 baffle 210 sound
absorbing material 410 loop 600 directional acoustic generator 610 specific sound area 1010,
1110 pre-processing part 1020, 1120 control part 1030, 1130 sound generation part 1111 low
frequency pass filter (LPF) 1112 High frequency pass filter (HPF) 1113 Compensator 1114
Inverse filter 1130 Sound generator 1121 Low frequency domain processor 1122 High
frequency domain processor 1123 Combiner
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