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JP2009088784

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
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DESCRIPTION JP2009088784
PROBLEM TO BE SOLVED: To output a plurality of viewable audios by selecting any one of a
plurality of audios. SOLUTION: A car audio apparatus 1 comprises a first reverse phase
generation unit 13 for generating a first reverse audio signal in reverse phase to a first audio
signal, and a second reverse audio signal in reverse phase to a second audio signal. , A first mixer
16 outputting a first mixing signal obtained by mixing the first audio signal and the second
inverse audio signal, a second audio signal and a first inverse signal. And a second mixer
configured to output a second mixing signal obtained by mixing the audio signal. [Selected
figure] Figure 1
Voice playback device
[0001]
The present invention relates to an audio reproduction apparatus, and more particularly to an
audio reproduction apparatus that reproduces a plurality of audios simultaneously.
[0002]
In recent years, vehicles are often equipped with an audio reproduction device such as a car
audio.
A vehicle may be carried by a plurality of people, and each of the plurality may wish to hear
different sounds. For example, the front seat passenger may listen to the radio and the rear seat
09-05-2019
1
passenger may view the video and audio from which the DVD was played. In this case, the
speaker mounted on the vehicle outputs the audio of the radio and the audio reproduced from
the DVD. For this reason, two different sounds are mixed, and there is a problem that it is difficult
to hear. In addition, when speakers are installed at the front and rear of the vehicle, the audio of
the radio can be output from the speakers at the front, and the audio reproduced from the DVD
can be output from the speakers at the rear, Even in this case, the audio of the radio output from
the front speaker is heard by the rear seat passenger, and the audio reproduced from the DVD
output from the rear speaker is the front seat passenger It sounds like For this reason, there has
been a problem that when a plurality of sounds are reproduced in one vehicle, each of the
plurality of sounds can not be heard well.
[0003]
In Japanese Patent Laid-Open No. 5-19775, a secondary sound having a phase relationship
opposite to that of noise from an engine or the like is obtained from the frequency of mechanical
vibration and a space acoustic transfer function such as a cabin, and this secondary sound is A
noise reduction device is described that offsets the noise by radiating.
[0004]
However, although the noise reduction device described in JP-A-5-19775 can reduce one kind of
sound, it has a problem that each of plural kinds of sounds can not be reduced at plural places.
Unexamined-Japanese-Patent No. 5-19775
[0005]
The present invention has been made to solve the above-mentioned problems, and one of the
objects of the present invention is to select any one of a plurality of sounds and to output a
plurality of viewable sounds. Providing an audio playback device.
[0006]
Another object of the present invention is to provide an audio reproduction method capable of
outputting audio that can be heard only at a predetermined position.
[0007]
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2
According to an aspect of the present invention for achieving the above-mentioned object,
according to an aspect of the present invention, a voice reproduction apparatus comprises: first
reverse voice generation means for generating a first reverse voice signal reverse in phase to a
first voice signal; A second reverse sound generation means for generating a second reverse
sound signal having a phase opposite to that of the sound signal; a first mixing means for
outputting a first mixing signal obtained by mixing the first sound signal and the second reverse
sound signal; And second mixing means for outputting a second mixing signal obtained by
mixing the second sound signal and the first reverse sound signal.
[0008]
According to this aspect, a first mixing signal obtained by mixing the first audio signal and the
second reverse audio signal is output, and a second mixing signal obtained by mixing the second
audio signal and the first reverse audio signal is output. Since it outputs, at the position where
the first voice signal is attenuated by the first reverse voice signal, the first voice signal can not
be heard and the second voice signal is attenuated by the second reverse voice signal. , The
second audio signal can not be heard.
Therefore, even when different voices are output, any one of the voices can be heard.
As a result, it is possible to provide an audio reproduction device capable of selecting any one of
a plurality of audios and outputting a plurality of audios that can be viewed.
[0009]
Preferably, the apparatus further comprises first delay means for delaying the first reverse
speech signal, and second delay means for delaying the second reverse speech signal.
[0010]
According to this aspect, since the first reverse speech signal is delayed, the first voice signal is
not reversed to the first reverse voice even when the transmission distances of the first voice
signal and the first reverse voice signal are different. It can be attenuated by the signal.
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Further, since the second reverse speech signal is delayed, the second voice signal is attenuated
by the second reverse speech signal even when the transmission distances of the second voice
signal and the second reverse speech signal are different. be able to.
[0011]
Preferably, the first delay means includes a first speaker outputting the first mixed signal, a
distance to the first viewing position, a second speaker outputting the second mixing signal, and
a distance to the first viewing position. The first delay time is determined based on the distance
between the first speaker and the second viewing position and the distance between the second
speaker and the second viewing position. 2 Determine the delay time.
[0012]
According to this aspect, the first delay time is determined based on the distance between the
first speaker and the first viewing position and the distance between the second speaker and the
first viewing position, and the first speaker and the first delay time are determined. The second
delay time is determined based on the distance to the second viewing position and the distance
from the second speaker to the second viewing position.
Therefore, the first voice signal can be attenuated by the first reverse voice signal, and the
second voice signal can be attenuated by the second reverse voice signal.
[0013]
Preferably, the apparatus further comprises speed detection means for detecting the movement
speed, the first delay means includes first correction means for correcting the first delay time
according to the detected movement speed, and the second delay means detects the movement
speed. And second correction means for correcting the delay time according to the moving speed.
[0014]
According to this aspect, the first delay time is corrected according to the moving speed, and the
second delay time is corrected according to the moving speed.
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Therefore, even when mounted on a mobile body, the first voice signal can be attenuated by the
first reverse voice signal, and the second voice signal can be attenuated by the second reverse
voice signal. .
[0015]
Preferably, the first mixing means includes a first volume control stage for changing the volume
of the second reverse audio signal, and the second mixing means includes second volume control
means for changing the volume of the first reverse audio signal. .
[0016]
According to this aspect, since the volume of the second reverse voice signal is controlled, the
second voice signal is attenuated by the second reverse voice signal and the second reverse voice
signal is sent to the listener who listens to the first voice signal. Can be difficult to hear.
Further, since the volume of the first reverse voice signal is controlled, the first voice signal is
attenuated by the first reverse voice signal, and the listener who listens to the second voice signal
is made difficult to hear the first reverse voice signal. be able to.
[0017]
According to another aspect of the present invention, an audio reproduction apparatus comprises
an audio signal generating means for generating an audio signal, a first output means for
outputting an audio signal generated by the audio signal generating means, and an output signal
having a reverse phase to the audio signal. Reverse voice generation means for generating a
reverse voice signal; and second voice output means for outputting the generated reverse voice
signal.
[0018]
According to this aspect, since the voiced voice signal is output and the voice signal having the
phase opposite to that of the voice signal is output, the position where the voice signal is
attenuated and the position where the voice signal is not attenuated occur.
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Therefore, the audio signal can not be heard at the position where the audio signal is attenuated
by the reverse audio signal.
For this reason, the position which can hear an audio | voice and the position which can not be
heard generate | occur | produce. As a result, it is possible to provide an audio reproduction
device capable of outputting audio that can be heard only at a predetermined position.
[0019]
Preferably, the apparatus further includes delay means for delaying the audio signal generated
by the audio signal generation means and inputting the delayed signal to the first output means.
[0020]
According to this aspect, the voice signal can be efficiently attenuated because the voice signal
can be delayed and output by the time for generating the reverse voice signal.
[0021]
Hereinafter, embodiments of the present invention will be described with reference to the
drawings.
In the following description, the same components are denoted by the same reference numerals.
Their names and functions are also the same. Therefore, detailed description about them will not
be repeated.
[0022]
In the following description, a car audio apparatus will be described as an example of an audio
reproduction apparatus, but the apparatus is not limited to a car audio apparatus as long as it is
an apparatus capable of reproducing plural types of audio simultaneously. It may be an audio
device installed fixed to
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[0023]
<First Embodiment> FIG. 1 is a functional block diagram showing an example of the function of a
car audio apparatus according to one of the embodiments of the present invention.
Referring to FIG. 1, a car audio apparatus 1 includes a navigation I / F (interface) 2, a card I / F 3,
a hard disk drive (HDD) 4, a DVD (Digital Versatile Disk) drive 5, and a plurality of compressions.
First and second selectors 11 and 21 for selecting one of audio signals, first and second decoders
12 and 22 for decoding compressed audio signals, and an audio signal in reverse phase to the
input audio signal Two types of analog audio signals: first and second reverse phase generators
13 and 23 to be generated; first to fourth D / A converters 14, 15, 24 and 25 for converting
digital audio signals to analog; And a front speaker 17 and a rear speaker 27.
[0024]
The navigation I / F 2 is an interface for connecting to the navigation device, receives an audio
signal output from the navigation device, and outputs the input audio signal to the first selector
11 and the second selector 21. The voice signal output from the navigation device is, for
example, a voice signal generated by voice synthesis of text for navigating.
[0025]
The card I / F 3 has a removable memory card, accesses the mounted memory card, reads out the
compressed audio signal stored in the memory card, and reads out the compressed audio signal
read out from the first selector 11 and the second selector 11. It outputs to the selector 21. The
HDD 4 accesses a hard disk (HD) as a mass storage device, reads the compressed audio signal
stored in the HD, and outputs the read compressed audio signal to the first selector 11 and the
second selector 21. The DVD drive 5 reads the compressed audio signal recorded on the DVD,
and outputs the read compressed audio signal to the first selector 11 and the second selector 21.
[0026]
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The first selector 11 selects one of the plurality of compressed audio signals output from the
navigation I / F 2, the card I / F 3, the HDD 4 and the DVD drive 5, and outputs the selected one
to the first decoder 12. Which one of the plurality of compressed audio signals is selected by the
first selector 11 follows the operation input by the user to the operation unit. Here, the first
selector 11 selects one of the plurality of compressed audio signals in accordance with an
operation input by the user to the front operation unit provided in the front seat.
[0027]
The first decoder 12 decodes the compressed audio signal input from the first selector 11 and
outputs a digital audio signal obtained by decoding to the first reverse phase generation unit 13
and the first D / A conversion unit 14.
[0028]
The first reverse phase generation unit 13 generates a voice signal of the reverse phase to the
voice signal based on the digital voice signal input from the first decoder 12, and generates the
voice signal of the reverse phase to the second D / A. It is output to the conversion unit 15.
[0029]
The first D / A conversion unit 14 converts the digital audio signal input from the first decoder
12 into an analog audio signal, and outputs the analog audio signal to the first mixer 16.
The second D / A conversion unit 15 converts the reverse-phase digital audio signal input from
the first reverse-phase generation unit 13 into an analog audio signal, and outputs the analog
audio signal to the second mixer 26.
[0030]
The second selector 21 selects one of the plurality of compressed audio signals output from the
navigation I / F 2, the card I / F 3, the HDD 4 and the DVD drive 5, and outputs the selected one
to the second decoder 22.
Which one of the plurality of compressed audio signals is selected by the second selector 21
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8
follows the operation input by the user to the operation unit. Here, the second selector 21 selects
one of the plurality of compressed audio signals in accordance with an operation input by the
user to the rear operation unit provided in the rear seat.
[0031]
The second decoder 22 decodes the compressed audio signal input from the second selector 21
and outputs a digital audio signal obtained by decoding to the second inverse phase generator 23
and the third D / A converter 24.
[0032]
The second reverse phase generation unit 23 generates a voice signal of the reverse phase to the
voice signal based on the digital voice signal input from the second decoder 22, and generates
the fourth D / A of the generated voice signal of the reverse phase. It is output to the converter
25.
[0033]
The third D / A converter 24 converts the digital audio signal input from the second decoder 22
into an analog audio signal, and outputs the analog audio signal to the second mixer 26.
The fourth D / A conversion unit 25 converts the reverse-phase digital audio signal input from
the second reverse-phase generation unit 23 into an analog audio signal, and outputs the analog
audio signal to the first mixer 16.
[0034]
The first mixer 16 amplifies and mixes each of the two audio signals.
The second mixer 26 amplifies each of the two sounds and mixes the two sound signals. The first
mixer 16 includes a first volume control unit 16A. The first volume control unit 16A acquires,
from the second mixer 26, the amplitude after the second mixer 26 amplifies the analog audio
signal input from the third D / A conversion unit 24, and based on the acquired amplitude, The
gain at the time of amplifying the analog voice signal of the reverse phase input from the 4th D /
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9
A conversion part 25 is controlled. In other words, the first volume control unit 16A outputs the
sound signal selected by the second selector 21 as the sound volume at which the analog sound
signal of the opposite phase input from the fourth D / A conversion unit 25 is output. Control
based on the volume. The first mixer 16 mixes and mixes the analog audio signal input from the
first D / A conversion unit 14 with the anti-phase analog audio signal output from the first
volume control unit 16A (mixing Signal) to the front speaker 17. The front speaker 17 outputs an
audio signal input from the first mixer 16.
[0035]
The second mixer 26 includes a second volume control unit 26A. The second volume control unit
26A acquires from the first mixer 16 the amplitude after the first mixer 16 amplifies the analog
audio signal input from the first D / A conversion unit 14, and based on the acquired amplitude,
The gain at the time of amplifying the analog voice signal of reverse phase input from the second
D / A conversion unit 15 is controlled. In other words, the second volume control unit 26A
outputs the sound signal selected by the first selector 11 as the sound volume at which the
analog sound signal of the opposite phase input from the second D / A conversion unit 15 is
output. Control based on the volume. The second mixer 26 mixes and mixes the analog audio
signal input from the third D / A conversion unit 24 with the analog audio signal of reverse
phase output from the second volume control unit 26A (mixing Signal) to the rear speaker 27.
The rear speaker 27 outputs an audio signal input from the second mixer 26.
[0036]
For example, the case where the navigation I / F 2 is selected by the first selector 11 and the
DVD drive 5 is selected by the second selector 21 will be described. An audio signal input from
the front speaker 17 from the navigation I / F 2 and an audio signal in reverse phase to the audio
signal input from the DVD drive 5 are output. On the other hand, an audio signal in reverse phase
to an audio signal input from the rear speaker 27 from the navigation I / F 2 and an audio signal
input from the DVD drive 5 are output. In this state, the sound heard by the rear seat user will be
described with reference to FIG.
[0037]
FIG. 2 is a diagram for explaining the principle of sound attenuation. Referring to FIG. 2,
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10
assuming that the position of the user's ear in the back seat is the viewing position L, the
distance between the viewing position L and the front speaker 17 is D1, and the distance
between the viewing position L and the rear speaker 27 is Assume D2. The distance D1 and the
distance D2 are positions where the sound output from the front speaker 17 and the sound in
antiphase output from the rear speaker 27 cancel each other. Therefore, for the rear seat user,
the voice output from the front speaker 17 is attenuated by the voice of the opposite phase
output from the rear speaker 27, and therefore, for the navigation output from the front speaker
17. I do not listen to audio. On the other hand, at the viewing position L, the sound output from
the rear speaker 27 does not cancel out the voice in reverse phase output from the front speaker
17. You can listen to the sound played back. However, the audio in the reverse phase to the audio
reproduced from the DVD output from the front speaker 17 is also viewed. For this reason, in the
first volume control unit 16A, it is preferable to convert the amplitude to such an extent that the
user of the rear seat can not hear it.
[0038]
Although the sound heard by the rear seat user is described here, the same applies to the sound
heard by the front seat user. That is, since the sound output from the rear speaker 27 is
attenuated by the sound in the opposite phase output from the front speaker 17, the user of the
front seat can reproduce the audio reproduced from the DVD output from the rear speaker 27. I
do not watch. On the other hand, the front seat user can view the audio for navigating output
from the front speaker 17. However, the audio in reverse phase with the audio for navigating
output from the rear speaker 27 is also viewed. Therefore, in the second volume control unit
26A, it is preferable to convert the amplitude to such an extent that the user of the front seat can
not hear it.
[0039]
<First Modification> FIG. 3 is a functional block diagram showing an example of the function of
the car audio apparatus in the first modification. Referring to FIG. 3, the difference from the
functional block diagram shown in FIG. 1 is that the first delay unit 18 is added between the
second D / A conversion unit 15 and the second mixer 26, and the fourth D The point is that the
second delay unit 28 is added between the / A conversion unit 25 and the first mixer 16. The
other configuration is the same as the configuration shown in FIG. 3, and therefore the
description will not be repeated here.
09-05-2019
11
[0040]
The first delay unit 18 receives an analog audio signal in reverse phase from the second D / A
conversion unit 15. The first delay unit 18 delays the analog audio signal and outputs the
delayed audio signal to the second mixer 26. The amount of delay by which the first delay unit
18 delays the audio signal is determined by the volume provided in the rear operation unit.
[0041]
The second delay unit 28 receives an analog audio signal in reverse phase from the fourth D / A
converter 25. The second delay unit 28 delays the analog audio signal and outputs the delayed
audio signal to the first mixer 16. The amount of delay by which the second delay unit 28 delays
the audio signal is determined by the volume provided in the front operation unit.
[0042]
Referring now to FIG. 2, the distance between the user's ear viewing position L and the front
speaker 17 is D1 (m), and the distance between the viewing position L and the rear speaker 27 is
D2 (m). is there. Assuming that the sound velocity is V (m / s), the time taken for the sound
emitted from the front speaker 17 to reach the viewing position L is D1 / V (s), and the sound
emitted from the rear speaker 27 is The time to reach the viewing position L is D2 / V (s).
Therefore, the delay amount is (D1−D2) / V (s).
[0043]
The position of the user's ear appearing in the front seat is the viewing position LL, the distance
between the viewing position LL and the front speaker 17 is DD1 (m), and the distance between
the viewing position LL and the rear speaker 27 is DD2 If it is (m), the time until the sound
emitted from the front speaker 17 reaches the viewing position LL is DD1 / V (s), and the sound
emitted from the rear speaker 27 reaches the viewing position LL The time to do this is DD2 / V
(s). Therefore, the delay amount is (DD2-DD1) / V (s).
[0044]
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12
Here, the amount of delay is adjusted by the volume possessed by the front operation unit and
the rear operation unit respectively provided to the front seat and the rear seat, but the viewing
position of the user's ear boarding the front seat LL and distances DD1 and DD2 to front and rear
speakers 17 and 27, respectively, and viewing positions L of the user's ears in the rear seat and
distances D1 and D2 to front and rear speakers 17 and 27, respectively It may be input in
advance. Furthermore, the position of the user's ear may be set in advance as the amount of
delay when the position of the user's ear on the front seat or the rear seat is known in advance.
[0045]
The car audio apparatus 1 according to the first modification delays the voice signal of the
opposite phase, so that the voice output from the rear speaker 27 is accurately attenuated by the
voice in the reverse phase output from the front speaker 17 Thus, the sound output from the
front speaker 17 can be accurately attenuated by the reverse phase sound output from the rear
speaker 27. For this reason, even when the distance transmitted by the audio signal is different
from the distance transmitted by the audio signal of the opposite phase, the audio signal can be
attenuated by the audio signal of the opposite phase.
[0046]
Second Modified Example The car audio apparatus 1 in the second modified example is
configured to change the delay amount in accordance with the speed of the vehicle. The present
invention is applicable to an open car or the like in which the air in the vehicle moves as the
vehicle moves. FIG. 4 is a functional block diagram showing an example of the function of the car
audio apparatus in the second modification. Referring to FIG. 4, the difference from the
functional block diagram shown in FIG. 3 is that the speed detection unit 31 is added and the
first delay unit 18A and the second delay unit 28A are modified. The other configuration is the
same as the configuration shown in FIG. 3, and therefore the description will not be repeated
here.
[0047]
The speed detection unit 31 detects the speed of the vehicle, and outputs the detected speed to
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the first delay unit 18 and the second delay unit 28. The first delay unit 18A includes a first
correction unit 33, and the second delay unit 28A includes a second correction unit 35.
[0048]
The first correction unit 33 included in the first delay unit 18A calculates the first delay
adjustment amount according to the speed input from the speed detection unit 31, and calculates
the first delay adjustment amount calculated in advance. The delay amount is corrected by
adding to. The first delay unit 18A delays the voice signal in reverse phase input from the second
D / A conversion unit 15 by the corrected delay amount, and outputs the delayed voice signal to
the second mixer 26.
[0049]
The second correction unit 35 included in the second delay unit 28A calculates the second delay
adjustment amount according to the speed input from the speed detection unit 31, and the delay
amount for which the calculated second delay adjustment amount is previously obtained. The
delay amount is corrected by adding to. The second delay unit 28A delays the audio signal in
reverse phase input from the fourth D / A converter 25 by the corrected delay amount, and
outputs the delayed audio signal to the first mixer 16.
[0050]
Here, referring to FIG. 2 further, assuming that the sound velocity is V (m / s) and the velocity of
the vehicle is v (m / s), the relative velocity at the viewing position L of the sound output from
the front speaker 17 is , (V + v) (m / s), and the relative velocity at the viewing position L of the
sound output from the rear speaker 27 is (V cos α−v) (m / s). Here, α is an angle between a
line segment connecting the viewing position L and the front speaker 17 and the traveling
direction. The time for the sound emitted from the front speaker 17 to reach the viewing position
L is D1 / (V cos α + v) (s), and the time for the sound emitted from the rear speaker 27 to reach
the viewing position L is It is D2 / (Vcos beta-v) (s). Here, β is an angle between a line segment
connecting the viewing position L and the rear speaker 27 and the traveling direction. Therefore,
the second delay adjustment amount is (D1 / (Vcosα + v) −D2 / (Vcosβ−v)) (s). In this case,
the delay amount is (D1−D2) / V (s) + (D1 / (Vcosα + v) −D2 / (Vcosβ−v)). The delay
adjustment amount may take a negative value.
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[0051]
The position of the user's ear appearing in the front seat is LL, the distance between the viewing
position LL and the front speaker 17 is DD1 (m), and the distance between the viewing position
LL and the rear speaker 27 is DD2 (m) If the sound emitted from the front speaker 17 reaches
the viewing position LL is DD1 / (V cos γ + v) (s), the sound emitted from the rear speaker 27
reaches the viewing position LL The time to do so is DD2 / (Vcosδ-v) (s). Here, γ is an angle
between a line connecting the viewing position LL and the front speaker 17 to the traveling
direction, and δ is a line connecting the viewing position LL to the rear speaker 27 and the
traveling direction. It is an angle. Therefore, the first delay adjustment amount is (DD2 / (Vcosγv) -DD1 / (Vcosδ + v)). In this case, the delay amount is (DD2−DD1) / V + (DD2 / (Vcosγ−v)
−DD1 / (Vcosδ + v)).
[0052]
Here, although the first and second delay adjustment amounts are calculated using the speed as a
parameter, a table in which the speed and the delay adjustment amount are associated is stored,
and the delay adjustment amount is calculated from the table. You may
[0053]
In the car audio apparatus 1 in the second modified example, the delay amount is adjusted
according to the speed of the vehicle, so that the sound output from the rear speaker 27 is of the
opposite phase output from the front speaker 17. The sound can be attenuated, and the sound
output from the front speaker 17 can be attenuated with the antiphase sound output from the
rear speaker 27.
[0054]
The second modification can also be applied to audio equipment installed outdoors.
In this case, the wind speed is detected instead of detecting the vehicle speed.
By replacing the speed in the second modification with the detected wind speed, the second
09-05-2019
15
modification can be applied to acoustic equipment installed outdoors.
[0055]
In the present embodiment, an example in which the speakers are mounted on the front and rear
of the vehicle is shown, but the speakers may be mounted on the left and right of the vehicle. In
this case, two passengers on the left and right of the vehicle can hear different sounds.
Furthermore, if speakers are mounted at four locations in the front, rear, left, and right of the
vehicle, four passengers on board can hear different voices. In this case, one voice signal and one
voice signal of the opposite phase of the other three voice signals are output from one speaker.
In this way, the same number of sounds as the number of speakers to be installed can be heard at
different positions.
[0056]
Second Embodiment FIG. 5 is a functional block diagram showing an example of functions of a
car audio apparatus according to a second embodiment. 5, car audio apparatus 1A includes
navigation I / F 2, card I / F 3, HDD 4, DVD drive 5, and selector 41 for selecting one of a
plurality of compressed audio signals. A decoder 42 for decoding a compressed audio signal, an
antiphase generator 43 for generating an audio signal in reverse phase to the input audio signal,
and a first to a second D / A converter 44 for converting a digital audio signal into an analog
signal 45, a first amplifier 47, a second amplifier 48, a front speaker 17, and a rear speaker 27.
[0057]
The car audio apparatus 1A generates an audio signal and the navigation I / F 2, the card I / F 3,
the HDD 4 and the DVD drive 5 output the generated audio signal to the selector 41. The selector
41 selects one of the plurality of compressed audio signals output from the navigation I / F 2, the
card I / F 3, the HDD 4 and the DVD drive 5 and outputs the selected one to the decoder 42.
Which one of the plurality of compressed audio signals is to be selected by the selector 41
follows the operation input by the user to the operation unit.
[0058]
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16
The decoder 42 decodes the compressed audio signal input from the selector 41 and outputs a
digital audio signal obtained by decoding to the antiphase generator 43 and the first D / A
converter 44. The antiphase generator 43 generates an audio signal in antiphase to the audio
signal based on the digital audio signal input from the decoder 42, and outputs the generated
antiphase audio signal to the second D / A converter 45. Output.
[0059]
The first D / A conversion unit 44 converts the digital audio signal input from the decoder 42
into an analog audio signal and outputs the analog audio signal to the delay unit 46. The delay
unit 46 delays the input audio signal, and outputs the delayed audio signal to the first amplifier
47. The delay amount for delaying the audio signal by the delay unit 46 is the time required for
the antiphase generator 43 to generate an audio signal of antiphase from the audio signal. The
delay unit 46 may delay the voice signal by a predetermined delay amount, or may obtain the
voice signal of the reverse phase from the reverse phase generation unit 43 and synchronize the
voice signal with the voice signal of the reverse phase. You may make it output. Alternatively, the
delay amount may be determined by the volume provided in the operation unit.
[0060]
The second D / A conversion unit 45 converts the digital audio signal of reverse phase input
from the reverse phase generation unit 43 into an analog audio signal, and outputs the analog
audio signal to the second amplifier 48.
[0061]
The first amplifier 47 amplifies the opposite phase audio signal input from the delay unit 46 and
outputs the amplified audio signal to the front speaker 17.
The second amplifier 48 amplifies the audio signal input from the second D / A converter 45 and
outputs the amplified audio signal to the rear speaker 27. The second amplifier 48 acquires from
the first amplifier 47 the amplitude after the first amplifier 47 amplifies the voice signal in
reverse phase, and the inverse input from the second D / A conversion unit 45 based on the
acquired amplitude. It controls the gain when amplifying the analog voice signal of phase. In
other words, based on the volume at which the audio signal selected by the selector 41 is output,
09-05-2019
17
the second amplifier 48 outputs the volume at which the analog audio signal in antiphase input
from the second D / A converter 45 is output. ,Control.
[0062]
For example, the case where the navigation I / F 2 is selected by the selector 41 will be
described. While an audio signal input from the front speaker 17 from the navigation I / F 2 is
output, an audio signal in reverse phase to the audio signal input from the rear speaker 27 from
the navigation I / F 2 is output.
[0063]
In this state, the user of the rear seat is for navigating the sound output from the front speaker
17 because the sound output from the front speaker 17 is attenuated by the reverse phase sound
output from the rear speaker 27. Never listen to the voice of On the other hand, the front seat
user can view the audio for navigating output from the front speaker 17. However, the audio in
reverse phase with the audio for navigating output from the rear speaker 27 is also viewed. For
this reason, in the second amplifier 48, it is preferable to convert it to an amplitude that can not
be heard by the front seat user.
[0064]
As described above, the car audio apparatus 1A according to the second embodiment is a front
speaker that generates an audio signal generated by any one of the navigation I / F 2, the card I /
F 3, the HDD 4 and the DVD drive 5. 17 and an audio signal in reverse phase to the audio signal
is output from the rear speaker 27. For this reason, it is possible that only the user boarding the
front seat hears an audio based on an audio signal generated by one selected from the navigation
I / F 2, the card I / F 3, the HDD 4 and the DVD drive 5. it can.
[0065]
Further, since the audio based on the audio signal generated by one selected from the navigation
I / F 2, the card I / F 3, the HDD 4 and the DVD drive 5 is delayed by the time for generating the
audio signal of the opposite phase. , Voice can be attenuated efficiently.
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[0066]
In the second embodiment, an example in which an audio signal is output from the front speaker
17 and an audio signal in reverse phase is output from the rear speaker 27 has been described. It
is also possible to provide a switch on the front side speaker 17 so that an audio signal is output
from the rear speaker 27 and an audio signal in reverse phase is output from the front speaker
17.
In this case, the user based on the audio signal generated by one selected from the navigation I /
F 2, the card I / F 3, the HDD 4, and the DVD drive 5 can only be heard by the user who is in the
back seat. Can.
[0067]
It should be understood that the embodiments disclosed herein are illustrative and nonrestrictive in every respect. The scope of the present invention is indicated not by the above
description but by the claims, and is intended to include all the modifications within the meaning
and scope equivalent to the claims.
[0068]
<Additional remarks> (1) A step of generating a first reverse voice signal reverse in phase to the
first voice signal, a step of creating a second reverse voice signal reverse in phase to the second
voice signal, and the first step A first mixing step of outputting a first mixing signal obtained by
mixing an audio signal and the second reverse audio signal, and a second mixing signal obtained
by mixing the second audio signal and the first reverse audio signal And a second mixing step. (2)
The audio reproduction method according to (1), further including the steps of: delaying the first
reverse audio signal; and delaying the second reverse audio signal. (3) Based on the first speaker
outputting the first mixing signal, the distance to the first viewing position, and the second
speaker outputting the second mixing signal to the first viewing position Determining the first
delay time, the second delay time based on the distance between the first speaker and the second
viewing position, and the distance between the second speaker and the second viewing position
The audio reproduction apparatus according to (2), further including: determining. (4) detecting
the moving speed, and delaying the first reverse speech signal includes correcting the first delay
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time according to the detected moving speed, the second reverse sound The audio reproduction
device according to (3), wherein the step of delaying the signal includes the step of correcting the
second delay time according to the detected moving speed. (5) The first mixing step includes
changing the volume of the second reverse audio signal, and the second mixing step includes
changing the volume of the first reverse audio signal. The audio reproduction device described
in. (6) generating an audio signal, outputting the audio signal, generating an inverse audio signal
in reverse phase to the audio signal, and outputting the generated inverse audio signal How to
play sound including. (7) The audio reproduction device according to (6), further including the
step of delaying the generated audio signal.
[0069]
It is a functional block diagram showing an example of a function of a car audio system in one of
the embodiments of the present invention. It is a figure explaining the principle which attenuates
a sound. It is a functional block diagram which shows an example of the function of the car audio
apparatus in a 1st modification. It is a functional block diagram which shows an example of the
function of the car audio apparatus in a 2nd modification. It is a functional block diagram
showing an example of a function of a car audio system in a 2nd embodiment.
Explanation of sign
[0070]
1 Car Audio Device, 2 Navigation I / F, 3 Card I / F, 4 HDD, 5 DVD Drive, 11 First Selector, 12
First Decoder, 13 First Anti-Phase Generator, 14 First D / A Converter, 15 second D / A
conversion unit, 16 first mixer, 16A volume control unit, 17 front speaker, 18, 18A first delay
unit, 21 second selector, 22 second decoder, 23 second reverse phase generation unit, 24 Third
D / A conversion unit, 25 fourth D / A conversion unit, 26 second mixer, 26A second volume
control unit, 27 rear speaker, 28, 28A delay unit, 31 speed detection unit, 33 first correction
unit, 35 first 2 correction unit.
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