JPH0366296

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DESCRIPTION JPH0366296
[0001]
FIELD OF THE INVENTION The present invention relates to a loudspeaker system having
bidirectionality. 2. Related Art In recent years, with the improvement of video imaging
technology, it has become possible to perform movie screening using a large screen even at
home. Accompanied with this, acoustic devices are also required to have the power and sound
quality required for a large screen. From such a background, as shown in FIG. 8, the audio device
combined with the home video reproduction device 13 has two to three speaker systems 8 in
front of the viewer 10 and two or more in the side or back. In many cases, a so-called surround
sound field reproduction apparatus using the speaker system 11 of FIG. The front channel of this
surround sound field reproduction apparatus is a signal such as soft voice to be reproduced or a
signal of background music, and the rear channel is a signal related to indirect sound or
reverberation synthesized from the signal of the front channel using a special processing
apparatus. I am dealing with The speaker system of each channel is required to have a
performance that basically corresponds to the signal to be handled, but if the timbres of the
direct sound component coming from the front and the indirect sound and sound components
coming from the back are different, the viewer may feel discomfort. The front and rear speaker
systems are preferably of the same type as much as possible. Also, since the rear channel handles
indirect sound, it is better to install a speaker system so that the sound from the speaker system
does not directly reach the viewer and sound image localization, thereby enhancing a good
surround effect. For example, as shown in FIG. 8, there is a method of achieving decentralization
of the sound source by using a large number of rear speaker systems 11 as shown in FIG.
However, on the other hand, it is required to be effective by using as few speaker systems as
possible because of the problem of installation location and cost. From the above points, a
speaker system as shown in the sectional view of FIG. 9 has been proposed as a speaker system
for the rear. In FIG. Reference numeral 2 denotes a speaker unit having the same performance,
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and reference numeral 3 denotes a cabinet. The speaker units 1 and 2 are electrically connected
to operate in antiphase with each other. FIG. 10 shows sound pressure frequency characteristics
in front of the speaker unit 1 or the speaker unit 2 of the speaker system shown in the crosssectional view of FIG. Further, FIG. 11 is a front view of the speaker unit 1 in a band where the
equivalent distance of the sound 4-sources of the speaker units 1 and 2 in the speaker system
shown in the sectional view of FIG. Oo This is an example of polar coordinate directivity
characteristics when the front side of the speaker unit 2 is 180 ░, and the sound pressure is
maximum at the front of the speaker unit 1.2, and the sound is equidistant from the speaker unit
12, that is, the side of the cabinet It shows both directions that minimize pressure.
Problems to be solved by the invention FIG. 12 is an arrangement example of an audio apparatus
in which the speaker system shown in FIG. 9 is combined with a home video reproduction
apparatus as a rear speaker system, as shown in FIG. When installed, the directional
characteristic of the rear speaker system 12 is bi-directional as shown in FIG. 11, and the sound
pressure is minimized near the viewing position, and the sound of the rear speaker system 12 is
directly viewed by the viewer It is possible to give a good surround effect to the viewer 10 while
using a small number without reaching 10. However, in the speaker system shown in FIG. 9, as
shown in FIG. 10O, in the band equal to or less than the frequency f0 where the equivalent
distance between the sound sources of the speaker unit 1.degree. The sound pressure of 2
cancels each other out and causes a sharp drop in the sound pressure level. Therefore, if it is
intended to reproduce to the low range, the cabinet is enlarged and the distance between the
speaker units 1 ░ 2 is increased to cause cancellation. Since the frequency to be started is
lowered or the amplifier which drives the speaker system requires a significant level correction, it
causes a problem in practice. In view of the above problems, it is an object of the present
invention to provide a speaker system which can give a good surround effect to a viewer while
using a small number of speakers and which does not cause a sharp drop in sound pressure level
in a low range. It is a thing. Means for Solving the Problems In order to achieve the above object,
the present invention attaches a speaker unit having the same performance to both a baffle plate
and a baffle plate opposite to a cabinet, and divides the inside of the cabinet into two cavities.
The cabinet is operated as a bus reflex type by providing a duct having an opening on a baffle
plate to which one side of the caddy is sealed and the other has a speaker unit attached to the
cavity to operate as a bus reflex type. It is electrically connected to be in phase. In the present
invention, a speaker unit having the same performance is attached to both the baffle plate and
the opposing baffle plate of the cabinet, the interior of the cabinet is partitioned to provide two
cavities, and one side of the cavity is sealed. A baffle is provided facing the baffle plate to which
the speaker unit relating to the cavity is attached, and a baffle having a temporary opening is
provided to operate as a bus reflex type, and the two speaker units are electrically connected so
as to be in opposite phase to each other It is
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In the present invention, a speaker unit having the same performance is attached to both the
baffle plate and the opposing baffle plate of the cabinet, the cabinet is divided into two cavities
by dividing the inside of the cabinet, and one side of the cabinet is sealed. The other is operated
as an open rear type, and both speaker units are electrically connected so as to operate in
reverse phase with each other. The present invention can provide a good surround effect to the
viewer while using a small number of the above-described configuration, and does not cause a
sharp drop in sound pressure level in the low range. Embodiments Hereinafter, one embodiment
of the present invention will be described with reference to the drawings. In FIG. 1, speaker units
having the same performance 1. 2 are attached to the baffle plate 5 opposed to the baffle plate 4
of the cabinet 3 respectively. Further, the cabinet 3 has an internal cavity partitioned by the
partition plate 6, the duct 7 is provided on the baffle plate 4 so that the speaker unit 2 operates
as a closed type and the speaker unit 1 operates as a bus reflex type. Furthermore, the speaker
units 1 and 2 are electrically connected to operate in opposite phase to each other. In the above
configuration, in the band of frequency f0 or more where the equivalent distance between the
sound sources of the speaker units 1 and 2 is a half wavelength, the sound radiated from the
speaker units 1 and 2 has the same amplitude antiphase characteristic. In the front of 2, the
maximum sound pressure and the positions at equal distances from the speaker units 1 and 2,
that is, the directivity with the minimum sound pressure on the side of the cabinet 1-3 are shown.
On the other hand, in the low frequency range, since the speaker unit 2 is sealed and the speaker
unit 2 is bus reflex, in the front of the speaker unit 1 when only the speaker unit 1 is driven, only
the speaker unit 2 is driven. The sound pressure frequency characteristic shown in FIG.
Therefore, although the speaker units 1 and 2 are in opposite phase, since the amplitude levels
are different, the cancellation of the sound pressure is alleviated, and a sharp drop in the sound
pressure level as in the speaker system shown in the cross sectional view of FIG. it can. FIG. 2C
shows a speaker unit 1 in the speaker system according to the present configuration. It is a
sound pressure frequency characteristic in the speaker unit 1 front when both 2 are driven. In
FIG. 3, speaker units 1 and 2 having the same performance are attached to the baffle plate 5
opposed to the baffle plate 4 of the cabinet 3 respectively.
Further, the cabinet 3 is divided into internal cavities by the partition plate 6, and the duct 7 is
provided on the baffle plate 5 so that the speaker unit 2 operates as a closed type and the
speaker unit 1 operates as a bus reflex type. Furthermore, the speaker units 1 and 2 are
electrically connected to operate in opposite phase to each other. In the above configuration, the
sound radiated from the speaker unit 1.2 has the same amplitude antiphase characteristic in the
band of the frequency f0 or more where the equivalent distance between the sound sources of
the speaker units 1 and 2 is a half wavelength. , And 2 show the directivity with the maximum
sound pressure and the position equidistant from the speaker units 1 and 2, that is, the sound
pressure minimum at the side of the cabinet 3. On the other hand, since the speaker unit 2 is
closed and the speaker unit 1 is bass reflex in the low frequency range, only the speaker unit 2 is
driven at the front of the speaker unit 1 when only the speaker unit 1 is driven. The sound
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pressure frequency characteristic shown in FIG. Accordingly, since the speaker units 1 and 2 are
in opposite phase but have different amplitude levels, the cancellation of the sound pressure is
alleviated, and a sharp drop in the sound pressure level as in the speaker system shown in the
cross sectional view of FIG. . FIG. 4C shows sound pressure frequency characteristics on the front
of the speaker unit 1 when both of the speaker units 1 and 2 are driven in the speaker system
according to the present configuration. In FIG. 5, speaker units having the same performance 1. 2
are attached to the baffle plate 5 opposed to the baffle plate 4 of the cabinet 3 respectively. In
addition, the cabinet 3 has a sealed portion formed by the baffle plate 4, the baffle plate 5, the
partition 6, and the side plates 7 b + c, d, and a rear surface formed by the baffle plate 5, the
partition 6, and the side plates 7 a, b, d It is divided 11-11 into the open part. Furthermore, the
speaker units 1 and 2 are electrically connected to operate in opposite phase to each other. In
the above configuration, the sound radiated from the speaker unit 1.2 has the same amplitude
antiphase characteristic in the band above the frequency where the equivalent distance between
the sound sources of the speaker units 1 and 2 is a half wavelength, so the speaker units 1 and 2
In the front of the figure, the maximum sound pressure and the positions equidistant from the
speaker unit 1.degree. On the other hand, in the low frequency range, the speaker unit 1 is in the
closed type operation, and the speaker unit 2 is in the open rear type operation. The sound
pressure frequency characteristics at the front of the speaker unit 2 when only the speaker unit
2 is driven show different low range reproduction limits as shown in FIG.
Therefore, since the speaker units 1 and 2 are in opposite phase but have different amplitude
levels, the cancellation of the sound pressure is mitigated, and the sound pressure level drops
sharply as in the speaker system 12-shown in the sectional view of FIG. Can be prevented. FIG.
6C shows sound pressure frequency characteristics on the front of the speaker unit 1 when both
of the speaker units 1 and 2 are driven in the speaker system according to the present
configuration. Although the speaker units 1 and 2 having the same performance are used in the
embodiment, it is also effective to use a multi-way speaker system configured of the speaker unit
having the same performance and the dividing network. Needless to say. FIG. 7 is a layout
diagram of a sound W device in which the speaker system according to the present invention is
combined with the home video reproduction device 13 as the rear speaker system, and the
speakers use the rear speaker system 9 one on each side A good surround effect can be provided
to the viewer 10 while using a small number of systems. As described in detail in the invention,
according to the present invention, it is possible to realize a speaker system which can give a
good surround effect to the viewer while using a small number of speakers and which does not
cause a sharp drop in sound pressure level in the low range. .
[0002]
Brief description of the drawings
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[0003]
1 is a layout view of an audio apparatus in which the speaker system of the present invention is
combined with a home video reproduction apparatus as a rear speaker system according to the
first embodiment of the present invention, and FIG. 8 is a conventional speaker 14 is a layout
diagram of an audio apparatus in which the system is combined with a home video reproduction
apparatus as a rear speaker system, 14-- 2. Speaker units 3. cabinets 4.
5 иии baffle plate, 6 иии middle partition plate, 7 иии duct, 8 иии front speaker system, 9 иии rear speaker
system, 1 o иии viewer, 1471 ииии Speaker system for the rear, 12: speaker system for the rear, 13:
video equipment, I4: input terminal, 15: internal wiring material.
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