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JPH07222278

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DESCRIPTION JPH07222278
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
projection type image display apparatus having a sound reproducing apparatus, particularly
suitable for a set when using a more compact housing.
[0002]
2. Description of the Related Art Recently, in a projection type image display apparatus, a
projection lens having a short focal length has been developed, and the set can be made compact.
In addition, in the direct-viewing television set, the overall length of the CRT is shortened, and in
the same manner, the size can be reduced. In particular, in the case of installation on a wall
surface, the reduction in the depth direction has a great advantage in the improvement of
installation in both cases of installation in the corners of a room. However, the reduction in the
depth direction makes it difficult to secure the volume of the sound reproducing apparatus (in
particular, the enclosure) attached inside the television set, and it is difficult to reproduce the low
frequency range of the audio signal. Thus, in order to obtain a rich bass feeling in a sound
reproduction apparatus in a television apparatus having a relatively compact form, in addition to
the two left and right speaker units, an independent speaker and a dedicated drive circuit are
provided. , And a configuration for reproducing the low frequency range component of the audio
signal. As such an example, it can see in Unexamined-Japanese-Patent No. 57-33891 grade | etc.,.
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1
[0003]
Also, in order to perform sufficient bass reproduction using a relatively small volume enclosure, a
speaker unit with low Q0 and f0 will be used. In such an audio reproduction apparatus, it is
difficult to reproduce the high sound range, so a speaker dedicated to high sound reproduction
(tweeter) is added and the audio signal is reproduced over a wide frequency band from the low
sound area to the high sound area. It is common.
[0004]
However, the addition of the system exclusively for bass reproduction shown in the abovementioned prior art to the projection type image display apparatus has the following two
drawbacks.
[0005]
(1) An increase in the number of parts and an increase in cost.
[0006]
(2) Even though the heat dissipation of electrical parts and the like is severe due to the compact
housing, the power consumption is further increased.
[0007]
Moreover, in the case of a compact housing, particularly when shortening in the height direction,
adopting the conventional arrangement of speaker units, a speaker unit that reproduces a band
around 1 kHz, which is the main band of the audio band. The position is close to the floor, and
the increase of the reflected sound from the floor causes a problem that the clarity of the sound
is deteriorated.
[0008]
That is, in a television apparatus having a compact housing, when sufficient internal volume of
the enclosure can not be secured as an audio reproduction apparatus embedded in the housing,
how to reproduce rich bass and obtain high clarity At the same time, the challenge is to have
both low costs.
[0009]
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2
[Means for Solving the Problems] The internal volumes of the left and right two sets of
enclosures incorporated in the casing are usually identical, and therefore the same configuration
as the enclosure with a small internal volume is used. The product is made different on the left
and right, and a difference is given to the bass reproduction characteristic (sound pressure
output characteristic in the bass region).
In addition, in the case where there are a plurality of speaker units constituting one set of sound
reproducing apparatus, the speaker unit for reproducing the middle midrange as a basic unit is
disposed in a unit arrangement separated from the floor.
[0010]
For example, the characteristics of bass reproduced from an enclosure having a large internal
volume can be expanded to a relatively low band, but the sound pressure level in the middle bass
range is likely to be reduced.
On the other hand, although it is difficult to extend the bass reproduced from an enclosure with a
small internal volume to a lower band, it is possible to secure a high sound pressure level in the
middle bass range.
At the viewing position, the sound pressure radiated from the two speakers is synthesized, so
that rich bass can be reproduced.
In particular, the bass region does not impair the sense of stereo since the directionality of the
sound is small.
Further, by separating the speaker unit for reproducing the medium sound from the floor, it is
possible to reduce the reflected sound from the floor and to reproduce the sound with good
clarity.
[0011]
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A first embodiment of the present invention will be described below with reference to FIG. FIG. 1
is a view showing an example in which the present invention is applied to a projection type
image display apparatus.
[0012]
In the embodiment, the projection type image display apparatus comprises a television case 1, a
screen 2, speaker boxes 3 and 4, speaker units 5 and 6, and circuit board installation units 10
and 11. The speaker unit 5 and the speaker box 3 constitute a first sound reproduction device,
and the speaker unit 6 and the speaker box 4 constitute a second sound reproduction device. The
internal volume of the speaker box 3 is smaller than the internal volume of the speaker box 4.
The acoustic characteristics reproduced from the speaker box having such non-control volume
will be described with reference to FIG. FIG. 2 shows sound pressure frequency characteristics
emitted from the first sound reproducing device and the second sound reproducing device. A
sound pressure frequency characteristic by the first sound reproducing device is shown as a
characteristic 7. When the influence of the stiffness of the volume of the speaker box 3 with
respect to the vibration system of the speaker unit 5 becomes large, the characteristic is slightly
raised in the low band (peak frequency: fP1). On the other hand, a sound pressure frequency
characteristic by the second sound reproducing device is indicated by a characteristic 8. When a
monaural signal (signal with the same phase and the same amplitude) is simultaneously input to
the speaker units 5 and 6, in the front of the housing 1 and at an equal distance from the speaker
units 5 and 6, Frequency characteristics (characteristic 9). In general, the bass component has
less sense of direction in human hearing, and no sense of incongruity is felt even if the sound is
emitted from either of the speaker units 5 and 6. On the other hand, when the internal volume of
the speaker box 4 is set equal to the internal volume of the speaker box 3 as in the prior art, the
frequency characteristic becomes the characteristic 7, and the sound pressure level of the low
frequency region is the low frequency region in the present embodiment. It falls below the sound
pressure level. With the configuration as in this embodiment, it is possible to obtain sound
pressure frequency characteristics in which the bass is extended, and at this time, material cost,
production cost increase and the like are completely eliminated.
[0013]
Next, a second embodiment of the present invention will be described with reference to FIG. FIG.
3 is a view showing an example in which the present invention is applied to a projection type
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image reproducing apparatus.
[0014]
In the present embodiment, the projection type image reproducing apparatus comprises a
television casing 1, a screen 2, speaker boxes 13 and 14, speaker units 15 and 16, and a port 17.
The members common to FIG. 1 are given the same numbers. Moreover, in order to demonstrate
the difference with FIG. 1, the circuit board installation parts 10 and 11 were abbreviate |
omitted. The speaker unit 15 and the speaker box 13 constitute a first sound reproduction
device, and the speaker unit 16, the speaker box 14 and the port 17 constitute a second sound
reproduction device. In this embodiment, the small volume speaker box has an enclosed
structure, and the large volume speaker box has a bass reflex system. The acoustic characteristics
reproduced from the speaker box having the non-control volume in FIG. 3 will be described with
reference to FIG. FIG. 4 shows sound pressure frequency characteristics emitted from the first
sound reproducing device and the second sound reproducing device. A sound pressure frequency
characteristic by the first sound reproducing device is indicated by a characteristic 20. When the
influence of the stiffness by the volume of the speaker box 13 with respect to the vibration
system of the speaker unit 15 becomes large, the characteristic is slightly raised (peak frequency:
fP2) in the low band. On the other hand, a sound pressure frequency characteristic by the second
sound reproducing device is indicated by a characteristic 18. With respect to various
characteristics of the speaker unit 16, the frequency characteristic 18 can be changed variously
depending on the volume of the speaker box 14 and the setting condition of the resonance
frequency of the port 17. For example, setting the port's resonant frequency low (eg, lengthening
the port length) causes a peak fp3 and a dip fd1. However, when a monaural signal (in-phase,
same-amplitude signal) is simultaneously input to the speaker units 15 and 16, a substantially
middle frequency characteristic (characteristic 19) of the characteristic 18 and the characteristic
20 can be obtained. In the present embodiment, since the first sound reproducing device and the
second sound reproducing device compensate for each other's frequency characteristics, the
material cost, the production cost increase, etc. are the same as in the first embodiment of the
present invention. Is completely eliminated, and flatter sound pressure frequency characteristics
can be realized more easily than in the first embodiment.
[0015]
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 5
is a view showing an example in which the present invention is applied to a projection type
image display apparatus.
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[0016]
In the present embodiment, the projection type image display apparatus comprises a television
case 1, a screen 2, speaker boxes 33 and 34, speaker units 35 and 36, and ports 37 and 38. The
members common to FIG. 1 are given the same numbers. Moreover, in order to demonstrate the
difference with FIG. 1, the circuit board installation parts 10 and 11 were abbreviate | omitted.
The speaker unit 35, the speaker box 33, and the port 18 constitute a first sound reproduction
device, and the speaker unit 36, the speaker box 34, and the port 37 constitute a second sound
reproduction device. In this embodiment, both the small volume speaker box and the large
volume speaker box have a bass reflex structure. The acoustic characteristics reproduced from
the speaker box having the non-control volume in FIG. 5 will be described with reference to FIG.
FIG. 6 shows sound pressure frequency characteristics emitted from the first sound reproducing
device and the second sound reproducing device. A sound pressure frequency characteristic by
the first sound reproducing apparatus is indicated by a characteristic 41, and a sound pressure
frequency characteristic by the second sound reproducing apparatus is indicated by a
characteristic 40. With respect to the various characteristics of the speaker unit 35 (36), the
frequency characteristic 41 (40) can be changed variously depending on the volume of the
speaker box 33 (34) and the setting condition of the resonance frequency of the port 38 (37).
Although there is no limitation to these design conditions, for example, when the port sizes
(opening area, port length, etc.) are the same and (volume of box 33) <(volume of box 34).
Produces a peak fp4 and a peak fp5 in the respective sound pressure frequency characteristics,
and fp4> fp5. At this time, when a monaural signal (signal having the same phase and same
amplitude) is simultaneously input to the speaker units 35 and 36, the characteristic 39 can be
obtained. Since the first acoustic reproduction device and the second acoustic reproduction
device compensate each other's frequency characteristics, the peak is fp6, but the dip that is
likely to occur in the characteristic 40 can be suppressed, and at the same time, the bass range
from the characteristic 41 Can expand the playback range of In this embodiment, as in the first
and second embodiments, the material cost and the cost increase in production are completely
eliminated, and the sound reproducing apparatus has a port as compared with the first and
second embodiments. Therefore, there is freedom in design, and it becomes easy to realize
desired sound pressure frequency characteristics regardless of the volumes of the boxes 33 and
34.
[0017]
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7
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is a view showing an example in which the present invention is applied to a projection type
image display apparatus.
[0018]
In the present embodiment, the projection type image display apparatus comprises a television
case 1, a screen 2, speaker boxes 33 and 34, speaker units 35 and 36, and ports 37 and 48. The
members common to FIG. 5 are assigned the same reference numerals. The speaker unit 35, the
speaker box 33, and the port 48 constitute a first sound reproduction device, and the speaker
unit 36, the speaker box 34, and the port 37 constitute a second sound reproduction device. The
present embodiment is the same as the third embodiment of the present invention in that both
the small volume speaker box and the large volume speaker box have a bass reflex structure, but
the port 48 attached to the small volume speaker box 33 The length is different from the length
of the port 37 attached to the speaker box 34 on the large volume side. The difference with
respect to the third embodiment of the present invention will be described with reference to
FIGS. 7 and 8. The characteristics 40 are identical. On the other hand, although the sound
pressure frequency characteristics by the speaker unit 35, the speaker box 33, and the port 38
are shown by the characteristic 49, for example, the attenuation characteristics at the frequency
of fp5 or less (region shown by circle 51) It can be approached. As a result, in the overall
characteristics, fp6 in FIG. 6 and fp8 in FIG. 8 become substantially equal, but the falling
characteristics of the bass range can be made gentle, and richer bass can be reproduced. In this
embodiment, since the port length is changed between the first sound reproducing device and
the second sound reproducing device, it has more design freedom than the third embodiment of
the present invention. And, as in the first to third embodiments, the material cost and the cost
increase in production are completely eliminated.
[0019]
Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 9
is a view showing an example in which the present invention is applied to a projection type
image display apparatus.
[0020]
In the present embodiment, the projection type image display apparatus comprises a television
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case 1, a screen 2, speaker boxes 33 and 42, speaker units 35 and 36, and ports 37 and 48. The
members common to FIG. 7 are given the same numbers. The speaker unit 35, the speaker box
33, and the port 48 constitute a first sound reproduction device, and the speaker unit 36, the
speaker box 42, and the port 37 constitute a second sound reproduction device. The present
embodiment differs from FIG. 7 in that, as a means for changing the volume, an example is
shown in which the speaker box 42 is changed in the lateral direction, not in the depth direction.
It is completely the same as the embodiment.
[0021]
Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 10
is a view showing an example in which the present invention is applied to a projection type
image display apparatus.
[0022]
In the present embodiment, the projection type image display apparatus comprises a television
case 1, a screen 2, speaker boxes 33 and 43, speaker units 35 and 36, and ports 37 and 48. The
members common to FIG. 7 are given the same numbers. The speaker unit 35, the speaker box
33, and the port 48 constitute a first sound reproduction device, and the speaker unit 36, the
speaker box 43, and the port 37 constitute a second sound reproduction device. The present
embodiment differs from FIGS. 7 and 8 in that, as means for changing the volume, an example
where the speaker box 43 is changed not in the depth direction but in the height direction is
shown. This is exactly the same as the embodiment of FIGS. 7 and 9.
[0023]
In addition to the configurations shown in FIGS. 9 and 10, the shape of the speaker box on the
large volume side and the small volume side does not have to be a rectangular parallelepiped,
and for example, even if it is a triangular cross section, it does not matter.
[0024]
Next, a seventh embodiment of the present invention will be described with reference to FIG.
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FIG. 11 is a view showing an example in which the present invention is applied to a projection
type image display apparatus.
[0025]
In FIG. 11, parts that are the same as in FIG. 1 are given the same numbers. In this embodiment,
the projection type image display device includes a television case 1, a screen 2, speaker boxes 3,
4, speaker units 5, 6, an audio signal input terminal 25, a band pass filter (BPF 4) 26 addition
circuit 27, It is constituted by the output circuit 28. The band pass filter 26 and the adder circuit
27 constitute a peaking circuit for emphasizing the low band of the audio signal. The operation
will be described below with reference to FIG. FIG. 12 shows the sound pressure reproduced
from the speaker units 5 and 6 and the frequency characteristic of the pass band of the band
pass filter 26. As shown in FIG. A sound pressure frequency characteristic reproduced from the
speaker unit 6 is assumed to be a characteristic 22. Since the speaker box 3 has a smaller volume
than the speaker box 4, it has the form shown by the characteristic 21. However, setting the
characteristic of the peaking circuit as shown by the characteristic 23 can realize the frequency
characteristic shown by the characteristic 24. By setting the characteristics 24 to be substantially
the same as the characteristics 22, the synthetic sound pressure characteristics can also be made
to be substantially the same. Further, in the embodiments shown in FIG. 5, FIG. 7, FIG. 9, and FIG.
10, when the speaker box on the small volume side has a bass reflex type structure, the low band
peaking circuit of FIG. In this case, it is possible to align the phases of both the left and right
sound reproduction devices, including the sound pressure characteristics from the bass reflex
port, and improve the synthetic sound pressure characteristics shown in FIG. 6, FIG. Sound
pressure level can be increased.
[0026]
Next, an eighth embodiment of the present invention will be described with reference to FIG. FIG.
13 is a diagram showing an example in which the present invention is applied to an audio signal
processing circuit.
[0027]
In this embodiment, the projection type image display apparatus comprises audio signal input
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terminals 70 and 75, a first band pass filter (BPF1) 71, a second band pass filter (BPF2) 76,
adder circuits 72 and 77, and an output circuit 73. And 78, and speaker units 74 and 79. In the
present embodiment, sufficient bass reproduction is realized by the audio signal processing
circuit, which is a significant difference from the first to sixth embodiments.
[0028]
In the present embodiment, for example, the terminal 70 is an audio input terminal on the left
side, the terminal 75 is an audio input terminal on the right side, the speaker unit 74 is an
acoustic reproduction device on the left side, and the speaker unit 79 is an acoustic reproduction
device on the right side. Hereinafter, the operation will be described using FIG. 14 and FIG. 15
together. FIG. 14 is a diagram showing the frequency characteristic of the band pass filter, and
FIG. 15 is a diagram showing the acoustic characteristic reproduced from the speaker unit. The
frequency characteristic of the first band pass filter 71 is set to the characteristic 80, and the
frequency characteristic of the second band pass filter 76 is set to 81. In the characteristics 80
and 81, the center frequencies fc1 and fc2 of the passband are different from each other. The
audio signal input from the terminal 70 detects the audio band indicated by the characteristic 80,
and is added to the input audio signal using the addition circuit 72, and the output circuit 73
drives the speaker unit 74 to be input from the terminal 75 The audio signal detects the audio
band indicated by the characteristic 81, and is added to the input audio signal using the addition
circuit 77, and the output circuit 78 drives the speaker unit 79. Assuming that the frequency
characteristics of the speaker units 74 and 79 are represented by the characteristic 82, the audio
signal input from the terminal 70 has the characteristic 84 emphasized around the center
frequency fc1, and is input from the terminal 75. For an audio signal, the characteristic 83 is
emphasized with the center frequency fc2 as the center. As a result, the frequency characteristic
synthesized by the speaker units 74 and 79 becomes the characteristic 85, and the reproduction
range of the bass can be expanded with respect to the characteristic 82. In addition, by
appropriately setting the settings of fc1 and fc2 according to the sound pressure frequency
characteristics of the speaker units 74 and 79, emphasis is performed in a frequency range
different from that of the tone control circuit generally used conventionally. be able to. Further,
since this embodiment is based on means different from the first to sixth embodiments of the
present invention, it can be used together with the first to sixth embodiments of the present
invention.
[0029]
Next, a ninth embodiment of the present invention will be described with reference to FIG. FIG.
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16 is a diagram showing an example in which the present invention is applied to an audio signal
processing circuit.
[0030]
In the present embodiment, the projection type image display apparatus includes audio signal
input terminals 70 and 75, high pass filter (HPF) 91, band pass filter (BPF 3) 92, low pass filter
(LPF) 93, addition circuits 94, 95, 100 and 101. , And output circuits 73 and 78, and speaker
units 74 and 79. In this embodiment, the bass expansion with higher efficiency is performed as
compared with the embodiment of FIG. The same reference numerals as in the embodiment of
FIG. 13 denote the same functional parts. In the embodiment, for example, the terminal 70 is an
audio input terminal on the left side, the speaker unit 74 is an audio reproduction device on the
left side, the terminal 75 is an audio input terminal on the right side, and the speaker unit 79 is
an acoustic reproduction terminal on the right side. It is an apparatus. Hereinafter, the operation
will be described using FIG. 17 and FIG. 18 together. FIG. 17 shows the frequency characteristics
of the filters 91, 92 and 93, and FIG. 18 shows the acoustic characteristics reproduced from the
speaker unit. The frequency characteristic of the high pass filter 91 is a characteristic 106, the
frequency characteristic of the band pass filter 92 is a characteristic 105, and the frequency
characteristic of the low pass filter 93 is a characteristic 104. Assuming that the center
frequency of the characteristic 105 is fc3, the characteristics 104 and the characteristic 106 are
set to have substantially symmetrical pass band characteristics with respect to fc3. The operation
will be described for each frequency band of the audio signal. First, audio signals are input from
the terminals 70 and 75, respectively. The middle and high frequency components of the input
audio signal pass through the high pass filter 91 and are added to the speaker units 74 and 79
through the addition circuits 95 and 101 output circuits 73 and 78, respectively. Next, the bass
component near the midrange is selected by the band pass filter 92, and the left and right signals
are added in the adder circuits 94 and 95 and added to the output circuit 73. Further, the bass
components selected by the low pass filter 93 add the left and right signals in the adder circuits
100 and 101 and add the result to the output circuit 78. That is, in the frequency characteristics
shown in FIG. 16, the characteristic reproduced from the speaker unit 74 is the characteristic
111, and the characteristic reproduced from the speaker unit 79 is the characteristic 113. At this
time, since the comprehensive characteristic to be synthesized does not include mutually
interfering components in the low frequency range signal reproduced by the speaker units 74
and 79, it is possible to obtain the characteristic 110 by adding the characteristic 111 and the
characteristic 113. it can. In addition, since the present embodiment is based on means different
from the first to sixth embodiments of the first invention, it can be used in combination with the
first embodiment. By setting the frequencies of fc3 and fp4 and fp7 close to each other, for
example, in combination with the third and fourth embodiments, it becomes possible to perform
more efficient bass enhancement, and the burden of the output circuit (heat generation, There
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are also merits such as being able to reduce the load (such as power loss) of the power supply
circuit, such as the dynamic range).
[0031]
Further, in FIG. 16, the circuit block indicated by a dotted line frame 98 is a combination of a
high pass filter and a band pass filter, but if it is a high pass filter that can realize the frequency
characteristic of the characteristic 107 shown in FIG. The same operation can be obtained.
[0032]
As described above, although the present embodiment has been described focusing on an
example applied to a projection type image display apparatus, the same effect can be obtained
even if applied to a direct view type television.
[0033]
Next, a tenth embodiment of the present invention will be described with reference to FIG.
FIG. 19 is a view showing an example in which the present invention is applied to a projection
type image display apparatus.
[0034]
In FIG. 19, parts that are the same as in FIG. 1 are given the same numbers.
In the present embodiment, the projection type image display apparatus is constituted by a
television case 1, a screen 2 and speaker units 5 and 6. Numerals 201 to 205 indicate lengths,
and numerals 207 and 208 indicate paths of sound. In a compact television set it is necessary to
reduce the depth (201) as well as the height (202). However, since the height (203) of the screen
2 is constant, the distance (204) from the lower end of the screen 2 to the floor decreases. The
mounting position of the speaker 5 is often around half of the distance 204 or slightly below half
of the distance 204 in terms of appearance design, appearance stability and the like. As a result,
the distance (205) between the center of the speaker 5 (for example, the voice coil position of the
speaker) which is the sound generation position and the floor becomes short, and the direct
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sound path 207 radiated from the original speaker 5 is reduced. The path 208 of the reflected
sound from the floor is increased, and the intelligibility of the sound tends to be reduced. In the
present embodiment, by setting at least (distance 205)> (distance 204) / 2, indirect sound
components due to the path 208 are reduced, and the clarity of sound is improved.
[0035]
Next, an eleventh embodiment of the present invention will be described with reference to FIG.
FIG. 20 is a view showing an example in which the present invention is applied to a projection
type image display apparatus.
[0036]
In FIG. 20, parts that are the same as in FIG. 19 are given the same numbers. The projection type
image display apparatus of this embodiment is constituted by a television case 1, a screen 2, and
speaker units 65, 66, 67 and 68. For example, in the case of expanding the reproduction band of
the audio signal, a method of adding a speaker (tweeter) dedicated to high sound is used.
Reference numerals 67 and 68 indicate tweeters. Generally, the mounting position of the unit
(woofer) 65, 66 with a large aperture of the speaker is on the lower side than the mounting
position of the tweeters 67, 68 in terms of appearance design, appearance stability, etc. As
described in the seventh embodiment, the center position of the speaker for reproducing the
middle range of the audio signal should be (distance 205)> (distance 204) / 2. Therefore, the
mounting position of the woofer 65, 66 is disposed on the upper side of the tweeter 67, 68. This
reduces the indirect sound component due to the path 208 and improves the sound clarity. On
the other hand, although the attachment positions of the tweeters 67 and 68 approach the floor
surface, the influence of the reflection from the floor surface on the reproduced sound does not
cause much problems because the wavelength of the audio signal to be reproduced is short.
Further, the advantage of attaching the tweeters 67, 68 below the woofer 65, 66 will be
described with reference to FIG. Generally, when viewing an image, it is a non-fatigue visual
posture that the central position of the screen surface 2 is lower than the height of the eyes of
the viewer. At this time, the distance L2 from the woofer 65 to the viewer and the distance L2
from the tweeter 67 to the viewer are strictly considered. The sound generation positions of the
woofer 65 and the tweeter 67 are approximately the voice coils 69w and 69t. The voice coil 69w
is farther from the viewer than the voice coil 69t. Therefore, by mounting the woofer 65 upward,
the distance L1 and the distance L2 become substantially equal. As a result, the arrival time
difference between the sound waves emitted from the woofer 65 and the tweeter 67 is
eliminated, and there is an advantage that the time alignment is corrected.
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[0037]
The effect of time alignment correction is that the connection of the sound near the crossover
frequency of the tweeter 67 and the woofer 65 becomes smooth, and together with the reduction
of the reflected sound of the woofer 65, the high clarity sound is reproduced. be able to.
[0038]
Finally, a twelfth embodiment of the present invention will be described with reference to FIG.
FIG. 22 is a view showing an example in which the present invention is applied to a projection
type image processing apparatus.
[0039]
In FIG. 22, the same parts as in FIGS. 20 and 5 are denoted by the same reference numerals. In
the present embodiment, the projection type image processing apparatus is constituted by a
television case 1, a screen 2, woofer 65, 66, tweeters 67, 68, and ports 37, 38. A difference from
the eighth embodiment is that ports 37 and 38 for bass reflex are added. The mounting position
of the woofer 65, 66 is disposed at the bottom of the screen 2, the tweeters 67, 68 are disposed
below the woofer 65, 66, and the ports 37, 38 for bass reflex are disposed below the tweeters
67, 68. As a result, the bass component radiated from the port has an advantage that high sound
pressure can be obtained due to the influence of reflection by the floor, and the efficiency of bass
reflex can be improved.
[0040]
As described above, by using the present invention, it is possible to reproduce a sound with high
clarity and well-expanded low-pitched range, although it is in a compact form.
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