JPH04172795

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DESCRIPTION JPH04172795
[0001]
TECHNICAL FIELD The present invention relates to an on-vehicle speaker system that is used for
an on-vehicle acoustic device and reproduces a diffuse sound field. 2. Related Art As a speaker
system which does not emit sound directly from a diaphragm of a speaker unit of the prior art
and emits sound from a position away from the diaphragm, there is a wide directional speaker
system which forms a horn shape using a sound absorbing material. In addition, there is a
method of mounting on a door as a method of mounting that requires less depth of the in-vehicle
speaker. Hereinafter, the conventional on-vehicle speaker system as described above will be
described with reference to the drawings. FIG. 3 shows the structure of a conventional on-vehicle
speaker. In FIG. 3, 1 is a cabinet, 2 is a speaker unit provided inside the cabinet 1, 3a and 3b are
sound absorbing materials in a horn shape provided on the opening side of the cabinet I, 4 is a
speaker unit 2 It is a diff user installed ahead. This loudspeaker system can be thought of as a
front load horn with a horn made of sound absorbing material on the front of the closed
loudspeaker. However, the horn in this case is close to a straight horn and is not for improving
sound pressure, but operates as a sound path for radiating sound from a position distant from
the diaphragm. As described above, since this horn is a straight horn, when all the horns are
made of a reflective material, resonance occurs in the horn, and sound pressure characteristics
are obtained as shown in the sound pressure characteristics of FIG. A large peak dip appears. In
order to suppress this resonance, the horn is formed of the sound absorbing members 3a and 3b.
The special user 4 works as a simple phase equalizer and also works to reduce the volume
between the speaker unit 2 and the horn. The higher the volume is, the higher the frequency is
attenuated as shown by the sound pressure characteristic B in FIG. The speaker system has a slitlike opening as shown in the external view of FIG. This is to widen the directionality of the XX
'force direction. The directivity becomes higher at high frequency as the width of the opening is
narrower, and the directivity becomes lower at low frequency as the width is wider. 7 (a) shows
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the directivity direction characteristics of xx 'force direction in FIG. 4 and the seventh turn)
shows the directivity characteristics of YY' force direction in FIG. The narrow X-X 'force direction
(hereinafter referred to as the transverse direction) has wide directivity, and the wide Y-Y' force
direction has a narrow directivity after the wide Y-Y 'force direction. When such a speaker
system is used for in-vehicle use, the diffuse sound field can be reproduced in the vehicle
compartment.
SUMMARY OF THE INVENTION However, when the speaker system having the above-described
configuration is used as a vehicle, since the depth is large, a large amount of space is required for
mounting, and the mounting becomes difficult. The conventional door installation as shown in
FIG. 8 can be easily installed with a type of speaker, but when the driver 5a is a listener, the
sound of the speaker 7a of the driver's side door 6a (R channel) There is a big difference in the
distance from the listening position between the sound of the speaker 7b of the passenger side
door 6b and the sound (L channel) of the passenger side door 6b, and the balance of L-R at the
time of stereo reproduction becomes closer to R channel. Have. SUMMARY OF THE INVENTION
In view of the above-described problems, the present invention provides an on-vehicle speaker
system which can be easily mounted and can reproduce diffused sound fields in a vehicle interior
with well-balanced left and right sounds. Means for Solving the Problem In order to achieve the
object, the on-vehicle speaker system of the present invention is configured to separate a horn
unit made of a sound absorbing material and a speaker unit unit, and to provide a movable tube
for connecting them. This speaker system is installed on the right side of the lower part of the
dash board of the car for the right channel and on the left side for the left channel with the horn
opening facing the floor. At this time, the long side of the horn opening is set so as to be
substantially parallel to the side of the car. According to the above configuration, the speaker
unit and the cabinet part having a large volume in the speaker system shown in the prior art can
be installed at any position regardless of the position according to the above configuration, so
that the horn is mounted Becomes easy. Also, as described in the conventional example, the
opening of this horn is in the form of a slit, and the listener on the right seat sits on the speaker
side for the right channel, so the distance is near the right channel However, from the positional
relationship between the listener and each of the left and right speakers, at this listening position,
the horizontal directivity of the left speaker and the vertical directivity of the right speaker are
heard. The lateral directivity is wide and the sound pressure is almost the same as the on-axis
sound pressure, but the longitudinal directivity is narrow and the sound pressure is attenuated
more than the on-axis sound pressure. The speaker attachment can adjust the angle so that the
sound pressure difference between the left and right due to the directivity becomes equal to the
sound pressure difference caused by the distance difference, so that the left and right balanced
sounds can be reproduced. The same effect can be obtained for the left seat. Embodiment An
embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a
structural sectional view of an on-vehicle speaker system according to an embodiment of the
present invention, and FIG. 2 shows a method of installing the on-vehicle speaker system
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according to an embodiment of the present invention.
In FIG. 1, 8 is a horn outer frame, 9a and 9b are horn-shaped sound absorbing materials provided
inside the horn outer frame 8, 10 is a speaker unit, 11 is a cabinet surrounding the back of the
speaker unit 10, I2 is a speaker An equalizer 13 provided on the front surface of the diaphragm
of the unit 10 is a movable tube connecting the horn outer frame 8 and the equalizer 12. Further,
in FIG. 2, 14 is a dash board of a car, 15a is a horn portion of the speaker system when viewed
from the side, 15b and 15c are horn portions of the speaker system when viewed from above,
16a, 16b and 16c are received. I am a listener. First of all, the cabinet 11 provided for processing
the back sound of the speaker unit lO is of the closed type here, but the closed type 1 phase
inversion type and the open type are depending on how much the frequency of the bass
reproduction limit of the speaker system is made. , Etc. to an optimal shape. Next, a movable tube
13 is used to guide the front sound of the speaker unit 10 to the horn portion. This means that
the tube can be moved flexibly to allow the speaker unit portion to be installed at a free position.
It is necessary to make the diameter as thin as possible so that it does not become an obstacle at
the time of installation. However, if it is too thin, the high sound range is attenuated. Therefore,
in the present embodiment, a tube having a cross-sectional area of, for example, 0.3 times the
effective vibration area of the speaker unit 10 is used. In addition, in order to avoid disturbing
the wave front of the sound passing through the tube 13, when the tube is bent, one having a
small change in cross section is used. The front sound of the speaker unit 10 needs to be phaseequalized by the equalizer 12 before entering the tube 13 to be as perfect a plane wave as
possible. If the phase is disturbed, a peak dip occurs in the high range of the sound pressure
characteristic when the sound wave reaches the horn and is emitted from the horn opening. This
peak dip can not be suppressed by the sound absorbing material in the horn. The equalizer 12
also serves to reduce the volume of the front of the speaker unit. As described in the
conventional example, when the volume in front of the speaker unit is large, the high range of
the sound pressure characteristic is attenuated. For this reason, the distance between the
diaphragm of the speaker unit 10 and the equalizer 12 is set so as not to contact the equalizer
12 when the diaphragm is at the maximum amplitude, so as not to make an extra volume.
Thereby, the sound pressure characteristic A of FIG. 6 can be obtained, and the attenuation of the
high range becomes small. The sound from the equalizer 12 passes through the movable tube 13
and enters the horn.
The horn comprises a horn outer frame 8 and sound absorbing members 9a and 9b. The sound
before entering the horn passes through a tube that can be regarded as an acoustic tube with a
constant cross-sectional area, so when entering the horn, the acoustic cross section of the sound
path changes rapidly, resulting in an acoustic impedance mismatch. As a result, a reflected wave
to the incident wave is generated, which causes a resonance phenomenon and a peak dip as
shown in the sound pressure characteristic B of FIG. For this reason, in order to reduce reflection
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as much as possible, by providing a horn-shaped sound absorbing material in which the cross
section changes gradually in the horn outer frame 8, the acoustic impedance is gradually
changed to suppress the reflection and prevent the resonance. Can. The sound pressure
characteristic in this case is shown by the solid line A in FIG. In addition, since the horn in this
case is not a perfect horn for miniaturization, a sound absorbing material is used for the horn
wall to absorb the energy of sound. Since this horn has a slit-like opening as in the conventional
example, directivity characteristics as described in the conventional example can be obtained. If
the speaker system that operates as described above is installed with the horn openings facing
the floor on both lower sides of the dash board 14 of the car as shown in FIG. 2, the listener 16b
is close to the speaker system 15b and the speaker system The distance from 15c is long, and it
is not possible to listen at the same distance from each speaker system. However, from the
positional relationship between the listener 16b and each of the speaker systems 15b and 15c,
the horizontal directivity of the speaker system 15c and the vertical directivity of the speaker
system 15b are determined at this listening position as shown by the broken line in FIG. You will
be listening. Since the horizontal directivity is wide and the vertical directivity is narrow, when
considered as the same distance, the mid-high range is attenuated with respect to the speaker
system 15c because the speaker system 15b is vertical. By adjusting the mounting angle of the
speaker system so that the sound pressure difference due to the directivity is equal to the sound
pressure difference caused by the distance difference, the listener 16b may listen with the same
sound pressure from the speaker systems 15b and 15c. it can. In addition, since the horn
opening is installed on the floor, the listener hears the diffuse sound, and there is no influence on
some deviations in the listening position. The above effects are also obtained for the listener 16c.
As described above, in the speaker system of the present embodiment, after the installation
position of the horn portion is determined, the speaker unit portion is put in another open space,
so it is difficult to be limited to the installation position of the system.
Although the horn opening is directed to the floor surface, it may be directed to a direction other
than the floor surface by adjusting the directivity. Also, the speaker unit may be provided in the
cabin door. According to the present invention, by providing a movable tube which is freely
movable between the speaker unit and the horn, the speaker system of the vehicle interior can be
mounted at an optimum position in the vehicle easily and easily. Furthermore, by placing the
horn openings of the above speaker system on the floor at the lower right and left bottom of the
dash board in the vehicle compartment, sitting in either the driver's seat or the passenger's seat,
the left and right balanced diffused sound fields can be obtained. It is possible to realize an
excellent in-vehicle speaker system that can obtain the effect of being able to hear and listen.
[0002]
Brief description of the drawings
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[0003]
FIG. 1 is a structural cross-sectional view of an on-vehicle speaker system according to an
embodiment of the present invention, FIG. 2 is a view showing an on-vehicle system of the onvehicle speaker system according to an embodiment of the present invention, and FIG. 4 is a
perspective view of a conventional speaker system, FIG. 5 is a sound pressure frequency
characteristic view by the material of the horn wall of the horn opening slit type speaker system,
and FIG. 6 is a speaker Sound pressure frequency characteristics when changing the volume
between the horn of the system and the speaker unit 凪, Fig. 7 is a directivity characteristic
diagram of the speaker system, and Fig. 8 is a diagram showing an on-vehicle example of the
conventional on-vehicle speaker system. .
8 · · · · · · Horn outer frame, 9a, 9b · · · · · · · · · · · · · · · · · · · · · · Speaker unit, 11 · · · Cabinet 512 · · · · ·
· · · · 13 ······ Movable tube. Name of the agent Attorney Attorney Osamu Kojima Two people Figure
1 Figure 2 Wen 2171 (L ン n ≧ Cb) 131 s4 Figure 5 Figure! r6 jet) ξ Km number J (Hg streak 6
figures! Ｄ！ Number of terms between rH and fK f tHl [7 fig f] 11? 敏 (Hz) + b) 50. 9) IFI frozen
LHL), 6; b- received jJa, Δb-door γ straight, 7b-sleeker Fig. 8
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