JPH04137897

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DESCRIPTION JPH04137897
[0001]
[Object of the Invention] (Industrial field of application) The present invention relates to an onvehicle acoustic device adapted to perform sound field correction of sound in a vehicle.
(Conventional art) Conventionally, as an on-vehicle acoustic device mounted on a vehicle such as
a car, for example, there is one as shown in FIG. The vehicle-mounted acoustic device 103 shown
in FIG. 4 includes a sound source device 105 including an amplifying device provided at the
center of the instrument of the vehicle 101, and a right speaker 37R1 left speaker 37L installed
at both left and right sides of the instrument or in a door. (E.g., June 1987 Nissan Motor Co., Ltd.,
Service Bulletin No. 578). In the in-vehicle acoustic device 103, part of the sound reproduced
from the left speaker 107L directly reaches the listener's right ear through the path C, and part
of the sound reproduced from the left speaker 107L is the right side glass It reaches the
listener's right ear via a path reflected by 111R, and a sound pressure characteristic as shown in
FIG. 5 (a) is obtained. Here, the sound pressure characteristic by the path C is indicated by D, and
the sound pressure characteristic by the C1 path is indicated by D (the same applies hereinafter).
In addition, a part of the sound reproduced from the left speaker 107L passes through the path
directly to the listener's left ear, and -m of the sound reproduced from the left speaker 107L
reflects the path B reflected by the right side glass 111R. The pressure reaches the listener's left
ear and a sound pressure characteristic as shown in FIG. 5 (b) is obtained. Similarly, a part of the
sound reproduced from the right speaker 107R directly reaches the listener's right ear through
the path E, and a part of the sound reproduced from the right speaker 107R is reflected by the
left side glass 111 To reach the listener's right ear, and a sound pressure characteristic as shown
in FIG. 5 (c) is obtained. In addition, a part of the sound reproduced from the right speaker 107R
directly reaches the listener's left ear through the path H, and a part of the sound reproduced
from the right speaker 107R reflects the path G reflected by the left side glass 111L. After
reaching the listener's left ear, sound pressure characteristics as shown in FIG. 5 (d) are obtained.
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That is, in the on-vehicle acoustic device, the sound that is reflected or turned around and
reaches the listener with respect to the sound AX (hereinafter referred to as the original sound)
that reaches the ear directly from the speaker reaches the listener slightly later. As indicated by
X in (e), the sound quality is degraded by the above-mentioned reflected sound. Therefore, in the
conventional on-vehicle acoustic device, the deterioration of the sound quality due to the
reflected sound described above is corrected with the frequency-sound pressure characteristic so
as to become the characteristic Y of FIG. 5 (e). (Problems to be Solved by the Invention) However,
in the above-described conventional on-vehicle acoustic device, the sound quality is improved by
the frequency-sound pressure characteristic as described above, but the basic sound quality
improvement is In addition, there is a problem that so-called frequency noise remains, such as
the noise of a specific frequency and the like of hearing loudly.
As shown in the area 2 of FIG. 5 (e), this "fault of frequency" causes the reflected sound to reach
the ear in a very short time (2 to 5 rrzec) with respect to the original sound, so the human ear It
is generated because it can be perceived as a peak dip of a specific frequency without being
distinguishable from the reflection sound. The present invention has been made in view of such
conventional problems, and an object of the present invention is to provide an on-vehicle
acoustic device in which harmful reflected sound and the like are canceled. [Configuration of the
Invention] (Means for Solving the Problems) In order to achieve the above object, the present
invention provides an on-vehicle acoustic device for outputting an original signal supplied from a
sound source device as sound from a main speaker, wherein the main speaker Correction signal
generation means for generating a correction signal for canceling a harmful sound which is
output from the voice and directly affects the sound reaching the listener's ear, and the
correction signal generation means provided in the vicinity of the listener's ear And a secondary
speaker for outputting a correction voice from the correction signal generated in (Operation) In
the vehicle-mounted acoustic device according to the present invention, sub-speakers are
disposed in the vicinity of both ears, for example, on the left and right of the headrest, separately
from the main speakers reproducing the original signal supplied from the sound source device.
Then, the correction signal generated by the correction signal generation means is supplied to
the sub-speaker, and the correction sound is output from the sub-speaker to affect the sound
output from the main speaker and reaching the listener's ear directly. Gives you the ability to
offset harmful sounds. The present invention will be described below based on the drawings. FIG.
1 is a block diagram showing an embodiment of the acoustic device of the present invention. In
FIG. 1, an on-vehicle acoustic device 3 is mounted on a vehicle 1 such as a car. The on-vehicle
acoustic device 3 includes an amplifying device 5, left and right speakers 7R and 7L, and left and
right sub-speakers 9R19L. Specifically, the amplification device 5 is provided in front of the
vehicle 1 in the room. The amplification device 5 is configured to include a sound field correction
control circuit α, which is a correction signal generation unit that amplifies the original signal
from the sound source device and forms a correction signal capable of eliminating unnecessary
indirect sound. The left and right speakers 7R and 7L are installed on both front sides of the
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vehicle 1, and convert signals from the amplification device 5 into sound. The left and right subspeakers 9R and 9L are disposed on both sides of the headrest 8 in the vicinity of the listener's
ear, and convert the correction signal from the sound field correction control circuit α of the
amplification device 5 into sound. FIG. 2 is a block diagram showing the configuration of the
amplification device 5. As shown in FIG.
The amplification device 5 shown in FIG. 2 includes a sound field correction control circuit α,
and is configured as follows. That is, the amplification device 5 is composed of a left channel
amplification circuit 11L, a right channel amplification circuit 11R, and a sound field correction
control circuit α. Here, the left channel amplifier circuit 11L amplifies an original signal of the
left channel (L Ch) from a sound source device (not shown) and supplies the amplified signal to
the left main speaker 7L. Further, the right channel amplifier circuit 11R amplifies an original
signal of the right channel (RCh) from a sound source device (not shown) and supplies the
amplified signal to the left main speaker 7R. The sound field correction control circuit α is
configured as follows. That is, the phase shift circuit 13L can change the phase of the original
signal of the left channel by 180 degrees. The signal from the phase shift circuit 13 L has a delay
time DT. The delay circuit 15L1 is supplied to the delay circuit 17L of the delay time DT2 and the
delay circuit 19L of the delay time DT3. The phase shift circuit 13R can change the phase of the
original signal of the right channel by 180 degrees. The signal from the phase shift circuit 13R is
supplied to the delay circuit 19R1 of delay time DT4 and the delay circuit 15R of delay time DT5,
respectively, to the delay circuit 17H of delay time DT5. The delay circuit 15L delays the signal
from the phase shift circuit 13L by the delay time (DT +) in order to eliminate the harmful sound
reaching the right ear from the left main speaker 7L via the path C. The delay circuit 17L delays
the signal from the phase shift circuit 13L by the delay time (DT2) in order to cancel harmful
sound that reaches the right ear through the path from the left main speaker 7L. In addition, the
delay circuit 19R delays the signal from the phase shift circuit 13R by the delay time (DT4) in
order to eliminate the harmful sound arriving from the right main speaker 7R via the path F and
reaching the right ear. On the other hand, the delay circuit 15R delays the signal from the phase
shift circuit 13R by the delay time (DT5) in order to eliminate the harmful sound arriving from
the right main speaker 7R via the path H and reaching the left ear. The delay circuit 17R delays
the signal from the phase shift circuit 13R by the delay time (DTe) in order to eliminate the
harmful sound reaching the left ear from the right main speaker 7R through the path G. Further,
the delay circuit 19L delays the signal from the phase shift circuit 13L by the delay time (DT3) in
order to cancel harmful sound reaching the left ear from the left main speaker 7L through the
path B. The outputs of the delay circuits 15L, 17L, and 19R are added by the adder 27L via level
adjusters 21L, 23L, and 25R that adjust the levels, amplified by the amplifier circuit 29L, and
then supplied to the right auxiliary speaker 9R.
The outputs of the delay circuits 15R17R and 19L are added by the adder 27R through the level
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adjusters 21R, 23R and 25L that adjust the level, amplified by the amplifier circuit 29R, and then
supplied to the left auxiliary speaker 9L. Next, the operation of the above-described embodiment
will be described with reference to FIG. Essentially, only the sound E as shown in FIG. 3 (b) (R),
which has passed through the route E, should arrive at the right ear of the listener. However, in
reality, as shown in FIG. 3 (a) (R), the sound coming from the left main speaker 7L as a harmful
indirect sound and passing through the route C to the right ear of the listener and the left main
The sound of the path coming out of the speaker 7L and reflected by the right side glass etc. and
the sound coming out of the right main speaker 7R and reflected by the left side glass etc. as
shown in FIG. 3 (b) (R) And will be reached. Similarly, only the sound A as shown in FIG. 3 (c) (L),
which has originally exited from the left main speaker and passed through the path A, may be
directly reached to the left ear of the listener. However, as shown in FIG. 3 (d) (L), the sound
coming from the right main speaker 7R as a harmful indirect sound and passing through the
path H and from the right main speaker 7R are emitted to the left ear of the listener. The sound
of the path G reflected by the left side glass etc. and the sound coming out of the left main
speaker 7L and reflected by the right side glass etc. as shown in FIG. 3 (c) (L) reach the path B It
will be. First, the correction operation of the right ear will be described. The phase shift circuit 13
inverts the phase of the original signal of the left channel by 180 degrees. The output signal of
the phase shift circuit 13L is supplied to the delay circuit 15L, the delay circuit 17L, and the
delay circuit 19L. Similarly, the phase shift circuit 13R reverses the phase of the original signal of
the right channel by 180 degrees. The output signal of this phase shift circuit 13R is supplied to
the delay circuit 19R. As shown in FIG. 3 (a) (RH), the delay circuit 15L adjusts the delay time
(DT1) of the harmful sound of the path C from the left main speaker 7L reaching the right ear
and outputs the level adjuster 21L. Supply to As shown in measure 3 (a) (RH), the delay circuit
17L adjusts the delay time (DT2) of the harmful sound of the route from the left main speaker 7L
reaching the right ear, as a level adjuster 23L. Supply to As shown in FIG. 3 (b) (RH), the delay
circuit 19R adjusts the delay time (DT4) of the harmful sound of the path F from the right main
speaker 7R reaching the right ear and outputs the level adjuster 25R. Supply to
The level adjusters 21L, 23L, and 25R adjust the level of each output signal to a level at which
the harmful sound can be canceled. The signals adjusted in this way are added by the adder 27L,
amplified by the amplifier circuit 29L, and output as sound from the right auxiliary speaker 9R.
As a result, since the sound from the right auxiliary speaker 9R is opposite in phase to each
harmful sound and each level or the same, the harmful sound of the listener's right ear is
canceled. Next, the correction operation of the left ear will be described. The output signal that is
180 degrees out of phase by the phase shift circuit 13R is supplied to the delay circuit 15R1 and
the delay circuit 17R. Similarly, the output signal of the phase shift circuit 13L is supplied to the
delay circuit 19L. As shown in FIG. 3 (d) (LH), the delay circuit 15R adjusts the delay time (DT5)
of the harmful sound of the path H from the right main speaker 7R reaching the left ear as a level
adjuster 21H. Supply to As shown in FIG. 3 (d) (LH), the delay circuit 17R adjusts the delay time
(DTs) of the harmful sound of the path G from the right main speaker 7R reaching the left ear as
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a level adjuster 23H. Supply to As shown in FIG. 3 (c) (LH), the delay circuit 19L adjusts the delay
time (DTs) of the harmful sound of the path B from the left main speaker 7L reaching the left ear
as a level adjuster 25H. Supply to Each level adjuster 21R, 23R, 25L adjusts the level of each
output signal to a level at which the harmful sound can be canceled. The signals adjusted in this
way are added by the adder 27R, amplified by the amplifier circuit 29R, and output as sound
from the left auxiliary speaker 9L. As a result, since the sound from the left auxiliary speaker 9L
is in phase with or opposite to each harmful sound and each level is the same, each harmful
sound is canceled by the listener's left ear. Since it operates in this way, it is possible to hear the
original sound and to prevent the sound from being broken. As described above, according to the
present embodiment, the left and right sub-speakers for canceling harmful reflections are set
near the listener's left and right ears, and signals for canceling harmful sounds are formed for
each path. Since output from the secondary speaker is possible, it is possible to completely
eliminate the frequency characteristics due to reflected sound with a short time delay and
entangled sound, and the separation characteristic is greatly improved, and an improvement in
sound image localization is obtained. Is there? [Effects of the Invention] As described above,
according to the present invention, since the correction signal generating means and the subspeaker are provided in the vicinity of the listener's ear, the main speaker outputs the signal
directly to the listener's ear. It is possible to cancel out the harmful sound that affects the voice to
be reached, so that it is possible to completely eliminate the frequency response due to the
reflected sound and the surrounding sound.
[0002]
Brief description of the drawings
[0003]
1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a block diagram
showing the configuration of a sound field correction control circuit used in the embodiment.
FIG. 3 is a diagram for explaining the operation of the embodiment. Fig. 4 is a block diagram
showing a conventional on-vehicle acoustic device. Fig. 5 is a characteristic diagram for
explaining the operation of the conventional device. 1 ... vehicle 3, 3 ... acoustic device 5, 5 ...
amplification device, α · · Sound field correction control circuit 7R right main speaker 7L left
main speaker 9R right auxiliary speaker 9L left auxiliary speaker.
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