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JP2008270857

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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 JP2008270857
The present invention provides an acoustic reproduction system capable of reducing the
propagation of sound to the next house or the surrounding environment even when reproducing
at a large volume, and enabling each listener to obtain a good reproduction sound field.
SOLUTION: A first speaker is held by a first holding means without being attached to a baffle
plate so that sounds emitted from the front and back of a diaphragm of the speaker unit can be
added, in the vicinity of a listener. It is placed behind the head of the listener. The second and
third speakers are held and disposed by the second holding means on the left and right of the
first speaker in the vicinity of the listener. The separation means separates the low frequency
components from the input audio signal and the middle and high frequency components for the
left and right channels. The low frequency component separated by the separating means is
supplied to the first speaker, and the middle and high frequency components for the left and
right channels separated by the separating means are supplied to the second and third speakers.
[Selected figure] Figure 1
Sound reproduction system
[0001]
The present invention relates to a sound reproduction system.
[0002]
An audiovisual reproduction system called a home theater system is in widespread use.
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1
In this video and audio reproduction system, for example, video reproduction from a DVD (Digital
Versatile Disc) is performed by displaying it on a relatively large screen display, and sound
reproduction is performed using a multi-channel surround sound system, recently, 5.1. A channel
system is adopted to enable powerful video and audio reproduction.
[0003]
The 5.1-channel sound reproduction system requires four types of speakers: the front of the
listener (hereinafter referred to as the front), the front of the listener (hereinafter referred to as
the center), the back of the listener (hereinafter referred to as the rear) The subwoofer, which is a
speaker dedicated to the low frequency band, originally receives a band of 100 Hz or less in
monaural. Other speakers are responsible for 100 Hz to 20 kHz.
[0004]
In the conventional arrangement of speakers in a 5.1 channel sound reproduction system, the
front left channel speaker is on the left side, the front right channel speaker is on the right side,
and the center channel speaker is on the front side. Be placed. In addition, the rear left channel
speaker is disposed on the left side behind the listener, and the rear right channel speaker is
disposed on the right side. Furthermore, a subwoofer speaker for low frequency effect (LFE)
channel (low frequency dedicated) is disposed at an appropriate position.
[0005]
Each of the six speakers is attached to a speaker box and arranged at each position. Usually, the
front and rear six speakers are often arranged with a distance to the listener of, for example,
about 2 meters.
[0006]
In the conventional sound reproduction system, for example, speakers for the front left and right
channels in which a speaker box of about 15 liters is used are changed to small boxes of about 1
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2
liter and are also called satellite speakers. Of course there is no low frequency, so a low
frequency dedicated speaker called a subwoofer has been added to aid it. Thus, when the
speakers other than the subwoofer are small boxes, the crossover frequency of the audio signal
supplied to the subwoofer is often 150 Hz, which is slightly higher than the above 100 Hz, but
There is no change in the low frequency.
[0007]
When the 5.1 channel audio signal from the DVD is reproduced by the speaker system arranged
as described above, it is natural that a sufficient bass is reproduced. In addition, since the
reproduction side also has a special channel exclusively for the low-frequency area, it is possible
to have a powerful realism, such as in a room such as a movie or the like, where an unheard of
deep bass sounds in the room.
[0008]
However, in Japan where the house is small, there is a problem that the space for arranging the
six speakers as described above for reproducing the multi-channel surround sound can not be
secured, and the noise due to the sound leakage to the outside There's a problem.
[0009]
That is, in a normal 5.1 channel speaker configuration, a sound volume of about 90 dB or more is
required to reproduce powerful sound in DVD audiovisual appreciation.
Therefore, when the listener tries to obtain the effect of multi-channel surround well, it is
necessary to consider the problem of external noise.
[0010]
At this time, in general, high frequency sounds can be easily isolated, and considerable noise can
be attenuated with a wall or a door. However, in the case of low-frequency sounds such as 100
Hz or less, sound insulation can not be easily achieved, and in small Japanese houses, the room
can not be large enough to block the low-frequency sounds. . Especially the subwoofer's 50Hz
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3
and 40Hz bass sounds, and the sound is transmitted to a considerable range.
[0011]
For this reason, when the sound is reproduced from the subwoofer, the sound may reach the next
room as well as the upper and lower rooms and cause trouble. Sounds are particularly difficult in
low-band sounds, subwoofers are a big problem in Japanese housing situations, and there is a
current situation where it is not possible to fully use the sound reproduction system of 5.1
channels.
[0012]
In addition, even in the case of installing a sound reproduction system in a car, the abovementioned low band sound leakage often becomes a problem.
[0013]
In order to solve the above-mentioned problems, Patent Document 1 (Japanese Patent
Application Laid-Open No. 5-95591) reproduces medium to high sound with a small speaker (a
type in which a speaker unit is housed in a speaker box), and A sound reproduction system has
been proposed which reproduces sound in the vicinity of the listener's ear by headphones for
low-pitched sounds and bone conduction.
[0014]
According to the technique of Patent Document 1, since the bass is reproduced in the vicinity of
the listener's ear by headphones or bone conduction, even if a listener can hear a large volume, it
can be prevented from being transmitted to the next house. .
[0015]
The above-mentioned patent documents are as follows.
Unexamined-Japanese-Patent No. 5-95591
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4
[0016]
However, in the invention of Patent Document 1 described above, even if low-range sound is
reproduced in the vicinity of the ear, it is not a speaker but a vibrator using headphones or bone
conduction.
It is thought that obtaining a low-pass feeling equivalent to that of a speaker with a vibrating
body other than a speaker is not a sense that is generally accepted as generally accepted,
although there are individual differences.
In addition, the listener has to wear headphones and a headset for bone conduction, which is
bothersome.
[0017]
Furthermore, although the invention of Patent Document 1 alleviates the problem of noise
relating to low-range sounds, the problem of having to place a large number of speakers in a
narrow space is solved by the invention of Patent Document 1 Absent.
[0018]
Also, in the case where a large number of speakers, for example, six, are arranged, if a plurality of
listeners try to enjoy the reproduced sound at the same time, the left and right channels are
selected depending on the listening position of the multiple speakers of each listener. Etc. may
not be heard as the intended sound.
[0019]
In view of the above points, the present invention can reduce the propagation of sound to the
next house and the surrounding environment even when reproduced at a large volume, and
enables each listener to obtain a good reproduction sound field It aims at providing a sound
reproduction system.
[0020]
In order to solve the above-mentioned problems, in the sound reproduction system according to
the present invention, the speaker unit is attached to the first holding means without being
attached to the baffle plate so that sounds emitted from the front and back of the diaphragm can
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5
be added. A first speaker held in the vicinity of the listener and disposed behind the head of the
listener, and held by the second holding means on the left and right of the first speaker in the
vicinity of the listener Second and third speakers to be arranged, separating means for separating
and obtaining low-pass components from the input audio signal and middle and high-pass
components for the left and right channels, and low-pass components separated by the
separating means Means for supplying the first and second speakers, and means for supplying
the middle and high frequency components for the left and right channels separated by the
separation means to the second and third speakers. And wherein the Rukoto.
[0021]
In the present invention, since the first speaker is held in the vicinity of the listener, it is easy to
cause the listener to listen at a large volume even if the first speaker does not sound at a large
volume. .
[0022]
Then, since the speaker unit of the first speaker is not attached to the baffle plate, the sound
reproduced as sound is emitted from the front and back of the diaphragm of the speaker unit.
The sounds coming from the front and the back of the diaphragm of the speaker unit have
opposite phases (opposite phases), so the sounds propagating to the outside cancel each other
and are attenuated.
In particular, the lower range speech is significantly reduced according to the invention, since the
lower the range, the greater the attenuation.
[0023]
And in this invention, although the 2nd and 3rd speakers are arranged on the right and left of
the 1st speaker, since these 2nd and 3rd speakers are for middle and high frequency, it is
considered as a small speaker. And can be placed with the first speaker in the vicinity of each
listener.
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Therefore, each listener can obtain a good reproduction sound field.
[0024]
According to the sound reproduction system according to the present invention, it is possible to
reduce the reproduced sound in the low band, which causes a problem as noise to the
surroundings, and to allow each listener to obtain a good reproduction sound field.
[0025]
Hereinafter, several embodiments of a sound reproduction system according to the present
invention will be described with reference to the drawings.
[0026]
First Embodiment The sound reproduction system according to the first embodiment uses a video
signal and an audio signal reproduced by a DVD player and a digital broadcast signal received by
a television receiver to generate a video. It is an example in the case of performing surround
sound listening of surveillance and 5.1 channels.
[0027]
FIG. 1 is a diagram showing an outline of a sound reproduction system according to the first
embodiment.
[0028]
As shown in FIG. 1, the sound reproduction system according to the first embodiment includes a
television receiver 1 as a video monitor apparatus having a television tuner and two speakers
11FL and 11FR, and a DVD player 2 , The audio signal output device unit 3, the audio signal
reception distribution unit 4, and the first speaker 6, the second and third speakers 7L and 7R
provided in the vicinity of the user 5 and behind the head thereof. And is configured.
The audio signal reception and distribution unit 4 is also an embodiment of the sound
reproduction system of the present invention.
[0029]
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The first speaker 6 is a low frequency speaker, and in this embodiment, is disposed substantially
at the center rear of the head of the listener 5.
Also, the second and third speakers 7L and 7R are middle-high range speakers, and in this
example, on both sides of the low-range speaker 6, the sound emission directions are in the
directions of the left and right ears of the listener 5, respectively. It is oriented and arranged.
[0030]
In the first embodiment, two speakers 11FL and 11FR of the television receiver 1 are used for
reproducing the front left and right two channels of 5.1 channel surround sound.
The two speakers 11FL and 11FR may be incorporated in the television receiver 1, or may be
provided separately from the television receiver 1.
[0031]
In the first embodiment, the three speakers 6, 7L, 7R arranged in the rear of the vicinity of the
listener 5 are 5.1 channels in addition to the low-pass audio signal LFE as described later. An
audio signal of rear left and right two-channel audio in the surround audio is subjected to virtual
sound source processing in the audio signal output device unit 3 and supplied.
[0032]
The television receiver 1 includes a tuner capable of receiving a digital broadcast signal,
reproduces a video signal and an audio signal of a digital broadcast program from the received
digital broadcast signal, and digitally displays the display screen 1D of the television receiver 1
While displaying the reproduced video of the broadcast program, the speakers 11FL and 11FR
reproduce the reproduced sound of the digital broadcast program by sound.
[0033]
In this case, when the sound of the digital broadcast program is multi-channel surround sound,
the reproduced sound of the digital broadcast program emitted from the speakers 11FL and
11FR is the front left and right two channels, center channel, rear left and right two channels, etc.
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Voice is included.
[0034]
Then, in this embodiment, the audio signal Au 1 received and reproduced by the television
receiver 1 is supplied to the audio signal output device unit 3.
[0035]
The DVD player 2 reproduces and outputs the video signal and the audio signal recorded on the
DVD.
In this example, the video signal Vi reproduced by the DVD player 2 is supplied to the television
receiver 1, and a reproduced video by the reproduced video signal Vi is displayed on the display
screen 1D.
Further, the audio signal Au2 reproduced by the DVD player 2 is supplied to the audio signal
output unit 3 in this example.
[0036]
In this embodiment, the audio signal output device section 3 has a decoding function
corresponding to the 5.1 channel multi-channel surround audio system, and the audio of the
digital broadcast program received by the television receiver 1 is 5.1 channel surround When
reproducing by voice, an audio signal to be supplied to the first to third speakers 6, 7L and 7R
provided in the vicinity of the user's 5 ears and behind the head of the listener 5 is generated .
Then, the audio signal output device unit 3 multiplexes (multiplexes) the generated audio signals
to be supplied to the first to third speakers 6, 7L, 7R, and in this example, the audio signal
reception distribution is performed using radio waves. Wirelessly transmit to unit 4.
[0037]
The audio signal reception and distribution unit 4 receives radio waves from the audio signal
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9
output device unit 3, extracts the multiplexed audio signal from the received radio waves,
separates the audio signal by de-multiplexing and band division, and Separate from the audio
signal supplied to the speaker 6 and the audio signal supplied to the second and third speakers
7L and 7R, and supplied to the first speaker 6 and the second and third speakers 7L and 7R,
respectively. Do.
[0038]
Note that wireless transmission from the audio signal output device unit 3 to the audio signal
reception distribution unit 4 is not limited to radio waves, and ultrasonic waves or light may be
used.
[0039]
Further, the audio signal output device unit 3 is provided with three speakers 6 and 7 L provided
near the user's 5 ears and behind the head of the listener 5 when reproducing the video and
audio reproduced by the DVD player 2. , 7R, and generates audio signals to be supplied to the
two speakers 11FL and 11FR for the left and right two channels of the television receiver 1, and
supplies them to the corresponding speakers 11FL and 11FR, respectively. Do.
[0040]
In the first embodiment, the audio signal output device unit 3 transmits the audio signal L of the
front left channel and the center channel to the two speakers 11FL and 11FR for the left and
right two channels of the television receiver 1. The sum signal with the audio signal C and the
sum signal of the audio signal R of the front right channel and the audio signal C of the center
channel are supplied.
[0041]
Further, the audio signal output device unit 3 is in the vicinity of the listener 5, and for the three
speakers 6, 7L and 7R behind the head, the rear left and right channels subjected to so-called
virtual sound source processing to be described later. Low frequency component of sum signal of
voice signal RL * and low frequency voice signal LFE, middle high frequency component of sum
signal of voice signal RL * of rear left channel subjected to virtual sound source processing and
low frequency voice signal LFE, and virtual sound source processing The middle and high
frequency components of the sum signal of the rear right channel audio signal RR * and the low
frequency audio signal LFE are supplied.
[0042]
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10
[Speaker Arrangement Example of First Embodiment] Next, a speaker arrangement example in
the sound reproducing system according to the first embodiment described above will be
described with reference to FIG.
[0043]
As shown in FIG. 2, in this embodiment, a front left channel speaker 11FL is disposed on the left
side and a front right channel speaker 11FR on the right side of the listener 5 respectively.
[0044]
Since the speakers 11FL and 11FR are built in the television receiver 1 in this example, for
example, the front sides of the small-sized speaker boxes 12FL and 12FR (for example, the front
panel of the television receiver) are used as baffle plates. The speaker units 13FL and 13FR are
attached.
The speakers 11FL and 11FR are hereinafter referred to as front speakers when it is not
necessary to distinguish which channel.
[0045]
And, in this embodiment, three speakers 6, 7L, 7R are disposed in the vicinity of the left and right
ears of the listener 5 and at the back of the head.
Among them, the speaker 6 is for low frequency use, and in this embodiment, an elliptical
speaker with a relatively large aperture is used, and is disposed behind the center of the head of
the listener 5 (directly behind the head).
The speaker unit is not housed in the speaker box and is not attached to the baffle plate so that
sounds radiated from the front and back of the diaphragm of the speaker unit can be mixed. , Is a
so-called naked speaker configuration.
[0046]
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11
Further, the speakers 7L and 7R are middle to high frequency speakers, and are smaller in
diameter than the speaker 6, and the diaphragms of the listener 6 are from behind the head of
the listener 5 on the left and right sides of the speaker 6, respectively. It is arranged to face the
left and right ears of 5.
In this case, as in the case of the speaker 6, the configuration of a naked speaker not attached to
the baffle plate is adopted.
However, the speakers 7L and 7R for middle-high range reproduction may be attached to the
baffle plate and may be stored in the speaker box.
[0047]
In this embodiment, the speaker 6 disposed at the center of the back of the head near the listener
5 is the sum of the voice signal RL * of the rear left and right channels subjected to virtual sound
source processing and the low-pass audio signal LFE. The low frequency component of the signal
is supplied so that the low frequency sound is emitted from the speaker 6.
Therefore, in this embodiment, the speaker 6 functions as a subwoofer.
[0048]
As a result of this configuration, the low-frequency sound of the LFE channel is emitted near the
listener's ear by the speaker 6 behind the head of the listener 5, so that the listener 5 is heard at
a high volume.
However, at positions away from the listener 5, the sounds coming out from the front and the
back of the diaphragm of the speaker unit of the speaker 6 are 180 degrees out of phase with
each other, and cancel each other out, so they are hardly heard.
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As a result, it is possible to prevent the situation where the low-range sound propagates to the
surroundings of the next house and the like, as in the prior art, causing inconvenience.
[0049]
In order to confirm the attenuation of the low-range sound, in the anechoic chamber, as shown in
FIG. 3, the sound from the speaker unit 11SW with a diameter of, for example, 17 centimeters for
subwoofers is separated by a distance d from the speaker unit 11SW The sound was collected by
the microphone 14 at a distant position, and the frequency characteristic of the sound pressure
level was measured. As a result, it became as shown in FIG.
In this case, the speaker unit 11SW is not housed in a box or attached to a baffle plate.
[0050]
The four frequency characteristic curves in FIG. 4 are, as shown in FIG. 4, that the distance d
between the speaker unit 11SW and the microphone 14 is d = 10 centimeters, d = 20
centimeters, d = 40 centimeters, respectively. It is the one at d = 80 cm.
[0051]
From this FIG. 4, it was found that when the configuration of a naked speaker in which the
speaker unit was not put in the box, the sound of 1 kHz or less was considerably attenuated, and
the amount of attenuation was particularly large as the low frequency sound was obtained.
[0052]
And in the case of this embodiment, each distance dsw between the speaker 6 and the left ear
and the right ear of the listener 5 is a distance at which the low frequency sound is transmitted
to the listener 5's ear without much attenuation. In this example, dsw = about 20 centimeters.
[0053]
For example, while the distance between the speaker 6 and the ear of the listener 5 is 2 meters in
general, in this embodiment, the distance between the speaker 6 and each of the two ears of the
listener 5 is 20 cm. In the case of this embodiment, the distance is 1/10 compared to the
conventional one.
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[0054]
For this reason, in this embodiment, the energy required for the listener 5 to feel the same sound
pressure may be 1/100 of that in the general case described above.
That is, if an amplifier of 100 W (watt) is temporarily required in the above-mentioned general
example, in the case of this embodiment, the same sound pressure is felt even with the 1 W
amplifier.
[0055]
In this embodiment, the diffusion of the sound is small only by the difference of the audio signal
output supplied to the speaker, and the low sound, for example, 20 Hz, 30 Hz, 40 Hz, cancels in
phase and plays the role of subwoofer Almost no sound can be heard except in the immediate
vicinity of the speaker unit of the speaker 6.
On the other hand, the powerful sound effects included in DVD software are obtained by
recording a large amount of energy in this bass band, so the soundproofing effect becomes
greater.
[0056]
According to the above configuration, when focusing only on the low band sound and
considering that only the low band sound is to be attenuated, sufficient effects can be obtained.
[0057]
In the case of 5.1 channel surround sound, there are also center channel audio and rear left and
right two channel audio.
Conventionally, as shown by a dotted line in front of the listener 5 in FIG. 2, the center channel
audio speaker 11C is attached with the speaker unit 13C with the front side of the speaker box
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14
12C as a baffle plate, as shown in FIG. Thus, it is arranged on the front side of the listener 5.
[0058]
However, in this embodiment, the sound of the center channel is acoustically reproduced by
equally distributing and supplying the two speakers 11FL and 11FR of the television receiver
without providing the dedicated speaker 11C. Let's do it.
That is, the audio signal C of the center channel is added to the audio signals L and R of the front
left and right 2 channels, respectively, supplied to the speakers 11FL and 11FR, and the speakers
11FL and 11FR reproduce the sound. Conventionally, as shown by the dotted lines at the rear of
the listener 5 in FIG. 2, the rear left and right two-channel audio speakers 11RL and 11RR are
disposed on the front side of the small speaker box 12RL and RR respectively. The rear speaker
units 13RL and 13RR, which are attached as baffle plates, are disposed.
[0059]
However, in this embodiment, the sound in the rear left and right two channels is reproduced by
the two speakers 7L and 7R in the vicinity of both ears of the listener 5.
That is, the audio signal RL on the rear left channel is made into an audio signal RL * subjected to
virtual sound source processing, and is supplied to the speaker 7L facing the left ear behind the
listener 5 to reproduce the sound.
Further, the sound signal RR on the rear right channel is set as the sound signal RR * subjected to
virtual sound source processing, and is supplied to the speaker 7R facing the right ear behind the
listener 5 to reproduce sound.
[0060]
The speakers 7L and 7R, like the speaker 6, have a small distance to the ears of the listener 5, so
the rear left and right two-channel audio signals RL and RR also reduce the radiation energy in
that range to contribute to soundproofing. be able to.
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[0061]
Then, sound reproduction of the rear left and right two channels of voices subjected to virtual
sound source processing is performed by the speakers 7L and 7R arranged near the ears at the
rear of the listener 5. Since reverberation and the like are the main sound sources, the
localization position is not so important, so there is an effect that good surround sound can be
obtained while realizing low sound and low noise.
[0062]
As an example of the speaker arrangement in consideration of the above, there can be considered
a method of installing the speakers on a chair having a structure like a massage chair, for
example.
[0063]
FIG. 5 is a diagram for explaining an example in that case, and the speaker 6 to be disposed at
the center of the head rear of the listener 5 described above and the two speakers 7L and 7R on
both sides thereof are chairs. It is a figure which shows what was set as the structure attached to
the top part 21a of the backrest part 21 of 20. FIG.
[0064]
In this example, for example, the chair 20 is a business class seat-like structure of an airplane,
and the speaker holder 22 is attached to the top 21 a of the backrest 21 of the chair 20. The
speakers 6, 7L, 7R are attached and held.
That is, in this example, the first holding means for holding the first speaker 6 and the second
holding means for holding the second and third speakers are constituted by one speaker holding
tool 22. .
[0065]
6A and 6B illustrate an example of the speaker holder 22. FIG.
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16
The speaker holder 22 is made of, for example, a pipe 221 made of metal such as aluminum.
As shown in FIG. 6B, the pipe 221 is formed in a flat ring shape, and the speaker 6 and the
speakers 7L and 7R are fixedly held in the space formed by the ring.
[0066]
The pipe 221 is formed in a flat ring shape, and the ring portion is formed in a substantially U
shape behind the head of the listener 5 as shown in FIG. 6A. There is.
In this example, the U-shaped pipe 221 is attached to the left and right ends of the speakers 7L
and 7R such that the diaphragms of the speakers 7L and 7R face the left and right ears of the
listener 5, respectively. It has a structure that is slightly bent to the head side.
[0067]
Further, attachment legs 222a and 222b for attaching the ring-shaped pipe 221 to the backrest
21 of the chair 20 are provided in a connected manner, and the attachment legs 222a and 222b
allow the backrest 21 of the chair 20 to be attached. , For example, to be removably attachable.
That is, for example, the top 21a of the backrest 21 of the chair 20 is provided with an elongated
hole (not shown) into which the mounting legs 222a and 222b are inserted and fitted, and the
mounting legs 222a and 222b By being inserted into and fitted to the long hole 21, the mounting
and fixing is configured.
[0068]
Then, when the listener 5 of this U-shaped ring-shaped pipe 221 sits in the chair, the speaker 6 is
located at the center rear position of the head of the listener 5 and the speakers 7 L, 7R is fixed
to the pipe 221 and held.
[0069]
In the case of this example, when the listener 5 sits on the chair 20, the distance between the
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17
speakers 6, 7L and 7R and the head (especially the ear) of the listener 5 is about 20 cm in this
example, It is configured.
[0070]
The audio signal of the corresponding channel to each of the speakers 6, 7L and 7R is configured
to be supplied from the audio signal reception and distribution unit 3 through the signal line
(speaker cable) in this example.
[0071]
[Configuration Example of Audio Signal Output Device Unit 3 According to First Embodiment]
FIG. 7 is a block diagram showing a configuration example of the audio signal output device unit
3 according to the first embodiment.
The audio signal output device unit 3 in the first embodiment includes an audio signal processing
unit 300 and a control unit 100 formed of a microcomputer.
[0072]
The control unit 100 has a ROM (Read Only Memory) 103 in which a software program and the
like are stored through a system bus 102 and a RAM (Random Access Memory) 104 for a work
area with respect to a central processing unit (CPU) 101. A plurality of input / output ports 105
to 108, a user operation interface unit 110, a head rear transfer function storage unit 111, and
the like are connected.
The user operation interface unit 110 includes one configured by a remote commander and a
remote control reception unit, in addition to a key operation unit provided directly to the audio
signal output device unit 3 and the like.
[0073]
As described above, in this embodiment, the audio signal output device unit 3 can receive the
audio signal Au1 from the television receiver 1 and the audio signal Au2 from the DVD player 2.
The received audio signals Au 1 and Au 2 are supplied to the input selection switch circuit 301.
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[0074]
The input selection switch circuit 301 is switched by a switching signal through the input /
output port 105 of the control unit 100 in response to a user's selection operation through the
user operation interface unit 110.
That is, when the user selects audio from the television receiver 1, the switch circuit 301 is
switched to select the audio signal Au1, and when audio from the DVD player 2 is selected. The
switch circuit 301 is switched to select the audio signal Au2.
[0075]
Then, the audio signal selected by the switch circuit 301 is supplied to the 5.1 channel decoding
unit 302.
The 5.1 channel decoding unit 302 receives the audio signal Au1 or Au2 from the switch circuit
301, performs channel decoding processing, and outputs the audio signals L and R for the front
left and right channels, the audio signal C for the center channel, and the rear The audio signals
RL and RR of the left and right channels and the low-pass audio signal LFE are output.
[0076]
The audio signal L of the front left channel from the 5.1 channel decoding unit 302 and the
audio signal C of the center channel are supplied to the synthesizing unit 303 and synthesized,
and the synthesized output audio signal (L + C) is transmitted through the amplifier 305. It is
derived to the audio output terminal 307. The audio signal obtained at the output terminal 307 is
supplied to one speaker 11FL of the television receiver 1.
[0077]
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Also, the audio signal R on the front right channel from the 5.1 channel decoding unit 302 and
the audio signal C on the center channel are supplied to the synthesizing unit 304 and
synthesized, and the synthesized output audio signal (R + C) is amplified by the amplifier It is
derived to the audio output terminal 308 through 306. The audio signal obtained at the output
terminal 308 is supplied to the other speaker 11FR of the television receiver 1.
[0078]
The amplifiers 305 and 306 have a muting function to shut off the audio signal output, and are
configured to be muted by the muting signal through the input / output port 107 of the control
unit 100.
[0079]
Then, in this embodiment, when the audio signal Au1 from the television receiver 1 is received,
the audio signals reproduced by the television receiver 1 are acoustically reproduced from the
speakers 11FL and 11FR of the television receiver 1. The amplifiers 305 and 306 are muted and
cut off so that the audio signal from the audio signal processing unit 3 is not supplied to the
speakers 11FL and 11FR of the television receiver 1.
[0080]
On the other hand, when the audio signal Au2 from the DVD player 2 is received, the amplifiers
305 and 306 are not muted and the audio signal from the audio signal device unit 3 is supplied
to the speakers 11FL and 11FR of the television receiver 1. Ru.
[0081]
It should be noted that, in place of the configuration for muting control of amplifiers 305 and
306, when decoding an audio signal from television receiver 1 in 5.1 channel decoding section
302, audio signals L and R for the front left and right channels and The audio signal C may be
configured not to be decoded and output.
In that case, a control signal for that purpose may be supplied through the input / output port
106.
[0082]
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20
Next, the audio signals RL and RR of the rear left and right two channels obtained by being
decoded by the 5.1 channel decoding unit 302 are supplied to a rear transfer function
convolution circuit 310 as a virtual sound source processing unit.
[0083]
The rear transfer function convolution circuit 310 uses a digital filter, for example, to transfer the
head rear transfer function prepared in the head rear transfer function storage unit 111 in
advance to the left and right two channels from the 5.1 channel decoding unit 302. The voice
signals RL and RR of R are folded.
[0084]
Therefore, in the rear transfer function convolution circuit 310, when the input voice signal is
not a digital signal, it is converted into a digital signal, and after the head rear transfer function is
convoluted, it is converted back into an analog signal and output.
[0085]
In this example, the head rear transfer function is measured and determined as follows, and
stored in the head rear transfer function storage unit 111.
FIG. 8 is a diagram for explaining a method of measuring the head rear transfer function.
[0086]
That is, as shown in FIG. 8A, the left channel measurement microphone ML and the right channel
measurement microphone MR are installed in the vicinity of the left and right ears of the listener
5.
Next, the rear left channel speaker 11RL is arranged at a position where the rear left channel
speaker is usually arranged behind the listener 5.
Then, for example, the emitted sound when the impulse is acoustically reproduced by the rear
10-05-2019
21
left channel speaker 11RL is collected by the respective microphones ML and MR, and from the
collected sound signal, the left and right from the rear speaker 11RL are collected. Measure the
transfer function to the ear (head rear transfer function for the rear left channel).
[0087]
Similarly, for the rear right channel speaker 11RR, for example, the emitted sound when the
impulse is acoustically reproduced is picked up by the respective microphones ML and MR, and
from the picked up sound signal, left and right from the rear speaker 11RR Measure the transfer
function to the ear (head rear transfer function for the rear right channel).
[0088]
The head rear transfer function is a transfer function from each speaker to the ear when the rear
speakers 11RL and 11RR are placed at a position of 2 m, for example, at 30 degrees from the
rear center of the listener 5 to the left and right. It is good to measure and obtain the transfer
function obtained.
[0089]
Further supplement to the transfer function.
For example, in FIG. 8A, a transfer function coming from the left rear to the left ear is referred to
as a transfer function A.
Next, as shown in FIG. 8B, the transfer function obtained by measuring the transfer function from
the speaker 7L in the vicinity of the ear to the microphone ML is taken as a transfer function B.
Then, when a transfer function B is multiplied by a certain transfer function X, a transfer function
X which becomes a transfer function A is obtained, and the obtained transfer function X is
convoluted with the signal sound sent to the nearby speaker 7L. The sound emitted from the
speaker 7L is as if it came from the left rear 2 m.
The transfer function can be determined similarly for the right channel.
10-05-2019
22
[0090]
The transfer function X may not necessarily be determined, and in some cases, only the transfer
function A may be used. Although the above description has been described on behalf of one of
the transfer functions, it is needless to say that there are actually a plurality of transfer functions,
as also shown in FIG.
[0091]
The head rear transfer function measured as described above is stored in the head rear transfer
function storage unit 111, supplied to the rear transfer function convolution circuit 310 through
the input / output port 108, and the rear transfer function convolution circuit 310 It is folded.
Thus, when the sound signals RL * and RR * from the rear transfer function convolution circuit
310 are supplied to the speakers 7L and 7R arranged in the vicinity of both ears and sound is
reproduced, the listener 5 is as if it were the rear left and right As the audio is emitted from the
rear speakers 11RL and 11RR, the user listens to the reproduced audio.
[0092]
The levels of the sound signals RL * and RR * of the rear left and right channels subjected to
virtual sound source processing at this time may be lower than the signal levels when supplied to
the speakers 11RL and 11RR. This is because the speakers 7L and 7R are near the ears of the
listener 5.
[0093]
In this specification, the above processing is called virtual sound source processing because
sound is heard so as to be emitted from a virtual speaker position by the above-described HRTF
convolution.
[0094]
As described above, the audio signals RL * and RR * subjected to the virtual sound source
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23
processing from the rear transfer function convolution circuit 310 are supplied to the synthesis
units 311 and 312.
The low band audio signal LFE from the 5.1 channel decoding unit 302 is supplied to the
synthesis units 311 and 312.
[0095]
The output sound signals of the synthesis units 311 and 312 are signals to be supplied to the
speakers 7L and 7R, respectively. The output voice signals of the combining units 311 and 312
are supplied to a multiplexing unit 313 and multiplexed (multiplexed), and wirelessly transmitted
from the wireless transmission unit 314 to the audio signal reception distribution unit 4.
[0096]
[Configuration Example of Audio Signal Reception and Distribution Unit] The audio signal
reception unit 4 is configured as shown in FIG. 9 in this embodiment. A signal wirelessly
transmitted from the audio signal output device unit 3 is received by the wireless reception unit
41 and supplied to the multiplex decoding unit 42. The multiplex decoding unit 42 demultiplexes
the audio signal multiplexed to the received signal to decode the two channels of signals RL * and
RR *.
[0097]
The two-channel signals RL * and RR * from the multiplex decoding unit 42 are supplied to the
band dividing circuits 43L and 43R, respectively. In each of these band dividing circuits 43L and
43R, input signals RL * and RR * are separated into low band components SLL and SLR and
middle high band components SHL and SHR. For example, frequency components lower than
200 Hz are low frequency components, and frequency components higher than 200 Hz are
middle high frequency components. The separation frequency is not limited to 200 Hz, and may
be, for example, 100 Hz.
[0098]
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24
The left high-frequency component SHL of the left channel from the band division circuit 43L is
supplied to the speaker 7L through the amplifier 44L. Further, the right high-frequency
component SHR of the right channel from the band division circuit 43R is supplied to the speaker
7R through the amplifier 44R.
[0099]
Further, the low frequency components SLL and SLR from the band division circuit 43L and the
band division circuit 43R are supplied to the synthesizer 45 and synthesized, and the synthesized
output signal SL is supplied to the speaker 6 through the amplifier 46.
[0100]
Therefore, while the speaker 6 mainly reproduces the sound of the low frequency audio signal
LFE as a subwoofer, the speakers 7L and 7R reproduce the sound signals RL * and RR * of the
middle high region of the rear left and right channels subjected to virtual sound source
processing. .
[0101]
The audio signal output unit 3 is configured to supply corresponding audio signals to the first to
third speakers 6, 7L, and 7R through the speaker cable without providing the audio signal
reception distribution unit 4. Of course also good.
[0102]
As described above, according to the sound reproduction system of the first embodiment in
which the multi-channel speaker is attached to the chair 20 shown in FIG. 5, the number of
listeners 5 sitting on the chair 20 is smaller than the number of channels. In addition to being
able to enjoy high-volume, realistic multi-channel sound using the speaker of the present
invention, leakage of sound to the surroundings can be significantly reduced.
[0103]
In particular, in this embodiment, by placing the speaker 6 for bass reproduction near the
listener 5 and at the back of the head near the ear without storing the speaker 6 in the box, the
deep bass leaks to the adjacent room. Can be significantly attenuated.
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25
Further, as described above, since the voices of the rear left and right channels are also emitted
as virtual sound source processed by the speakers 7L and 7R in the vicinity of the ears of the
listener 5, the voice signal level can be lowered. it can.
Therefore, not only the bass but also the level of sound leakage to the surroundings can be
further lowered.
Therefore, for example, even when watching a DVD at midnight, it can be enjoyed at a sufficient
volume without worrying about others.
[0104]
In addition, since the speakers 6, 7L, 7R are disposed near the listener's ear, the audio signal
output power can be made about 1/100 of that in the conventional case in the extreme case,
energy saving can be achieved, and The cost of hardware (output amplifier) can be significantly
reduced.
Furthermore, since the audio output power can be small, there is an advantage that the speaker
can use a thin, light, inexpensive speaker which does not require a large stroke. In addition, since
the audio output power is reduced, the heat generation is reduced and the size of the device such
as a power source can be reduced, so that the battery can be driven and can be embedded in the
design of a chair or the like.
[0105]
Therefore, the energy saving of the sound reproduction system can be realized in total, and there
is an advantage that the sound reproduction system can be provided which reduces the noise to
the surroundings without reducing the satisfaction of the viewer.
[0106]
Even with a normal soundproof window, even if there is a performance that can attenuate 45 dB
10-05-2019
26
at 5 kHz, it drops to 36 dB at 1 kHz and 20 dB at 100 Hz.
Especially at 50 Hz or less, the amount of attenuation is further reduced, so the soundproofing
effect of the subwoofer according to this embodiment is remarkable, and the cost-effectiveness
that can be saved is very high considering that the sound reproduction of the room is enjoyed.
There is a big one.
[0107]
In the above description of the first embodiment, the audio signal Au2 is supplied to the speakers
11FL and 11FR of the television receiver 1 through the audio signal output device unit 3 when
the DVD player 2 is reproducing. The audio signal Au2 from the DVD player 2 is supplied to the
television receiver 1, and the audio mixed with the 5.1 channel audio from the speakers 11FL
and 11FR as in the reception of the digital broadcast program. May be emitted. In that case, the
audio signal system path supplied from the audio signal output device unit 3 to the speakers
11FL and 11FR of the television receiver 1 becomes unnecessary.
[0108]
The audio signal receiving and distributing unit can be provided at a predetermined position
such as under the seat surface of the chair 20.
[0109]
Also, the audio signal output device unit 3 may be configured to receive the multi-channel audio
signal supply source and the audio signal Au2 from the television receiver 1 or the DVD player 2
through the signal cable. It is necessary to connect the device 1 or the DVD player 2 to the chair
with a signal cable.
[0110]
Therefore, a DVD player or the like is provided with means for wirelessly transmitting multichannel audio signals using radio waves and light, and the audio signal output device section 3
receives the multi-channel audio signals transmitted wirelessly. By providing the receiving unit,
the signal cable between the DVD player 2 and the like can be eliminated.
[0111]
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27
As described above, when audio signal output from a multi-channel audio signal supply source
such as a DVD player is transmitted by radio waves or light, it becomes cordless between the
DVD player etc. and the sound reproduction system, for example The chair 20 equipped with the
sound reproduction system has the advantage of being able to move freely.
[0112]
In the above description, the speaker of the television receiver is used as the front speaker, but it
is of course possible to separately provide a dedicated front speaker.
In that case, a speaker for the center channel may be provided.
[0113]
In the above embodiment, the left and right front channels and the center channel are
acoustically reproduced using the speakers 11FL and 11FR of the television receiver, but the
audio signals of these left and right front channels and the center channel are also virtual sound
sources. Processing may be performed to supply the middle high frequency component to the
speakers 7L and 7R.
[0114]
In that case, the audio signals to the speakers 11FL and 11F1R of the television receiver 1 are
muted.
That is, for example, when the audio signal output device unit 3 and the audio signal receiving
and distributing unit 4 are powered on by the remote controller, the television receiver 1 may
control the audio signals to the speakers 11FL and 11FR to be muted. .
[0115]
Second Embodiment The above-described first embodiment is a case where the user sits in a
chair indoors and is configured to enjoy 5.1 channel surround sound while viewing the display
10-05-2019
28
screen.
On the other hand, the second embodiment is an example of the case where music is reproduced
by sound reproduction and enjoyed in a car.
[0116]
Also in this second embodiment, 5.1-channel surround sound can be reproduced. In this second
embodiment, all 5.1-channel surround sound channels are in the vicinity of the listener 5. In this
case, the three speakers 6, 7L, 7R are provided so as to emit sound so that the effects of noise
reduction and energy saving can be maximally exhibited.
[0117]
Further, in the second embodiment, the listener as the driver and the listener on the passenger
seat, for example, can enjoy 5.1 channel surround sound in an optimal environment. Do.
[0118]
FIG. 10 is a diagram showing an outline of the sound reproduction system according to the
second embodiment.
In FIG. 10, the same parts as those of the first embodiment described above are denoted by the
same reference numerals, and the detailed description thereof will be omitted.
[0119]
In the second embodiment, as shown in FIG. 10, the three speakers described above are disposed
in the driver's seat 91 and the passenger seat 92, respectively.
That is, for the listener 51 sitting in the driver's seat 91, in this example, the low-range speaker
61 is located at the head center rear of the head of the listener's head in the headrest portion
911 of the seat of the driver's seat 91 The speakers 71L and 72R for middle and high
frequencies are arranged.
10-05-2019
29
[0120]
In addition, for the listener 52 who sits in the passenger seat 92, in this example, the low-range
speaker 62 is located at the center rear of the head of the listener 52 in the headrest portion 921
of the seat of the passenger seat 92 Speakers 72L and 72R for middle and high frequencies are
arranged.
[0121]
The low frequency speakers 61 and 62 are naked speakers having the same configuration as the
speaker 6 of the first embodiment.
In addition, the speakers 71L and 71R for middle and high frequencies and the speakers 71L and
72R are configured in the same manner as the speakers 7L and 7R in the first embodiment,
respectively, and in this example, are configured as naked speakers.
The mid-high range speakers 71L and 71R and the speakers 71L and 72R may be attached to a
baffle plate instead of a bare speaker configuration and may be housed in a speaker box, as in
the first embodiment. .
[0122]
As shown in FIG. 10, in the second embodiment, an audio signal output device unit 30 is
provided instead of the audio signal output device unit 3 in the first embodiment.
The audio signal output device unit 30 performs virtual sound source processing on the audio
signals of the front left and right channels with the audio signal output device unit 3 in the first
embodiment, as described later, It differs in that two channels of signals to be transmitted are
generated.
[0123]
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30
In the second embodiment, the audio signal output device unit 30 is supplied with an audio
signal Au2 from the DVD player 2 and an audio signal Au3 from a CD (Compact Disc) player 8.
The audio signal Au2 from the DVD player 2 includes the case of 5.1 channel surround audio, but
the audio signal Au3 from the CD player 8 is an audio signal of left and right two channels.
[0124]
Then, in the audio signal output device unit 30 of the second embodiment, when audio signals of
the left and right two channels from the DVD player 2 and the CD player are input, as described
later, regarding the audio signals of the front left and right two channels The virtual sound
source processing is performed to generate audio signals of two channels to be transmitted to
the audio signal reception distribution unit 4 and transmit the audio signals to the audio signal
reception distribution unit 4.
[0125]
The audio signal reception and distribution unit 4 decodes the audio signal of two channels from
the received signal as described in the first embodiment, and the low frequency component and
the left and right sides of the audio signal of the two channels are The middle and high frequency
components of the channel are separated to generate signals to be supplied to the three speakers
61, 71L, 71R and 62, 72L, 72R, respectively.
[0126]
Then, the low frequency component SL generated by combining the low frequency components
SLL and SLR from the audio signal reception distribution unit 4 is supplied to the low frequency
speaker 61 of the driver's seat 91 and the low frequency of the passenger seat 92. The speaker
62 is supplied.
[0127]
The left-channel mid-high-frequency component SHL from the audio signal reception distribution
unit 4 is supplied to the mid-high-range speaker 71 L for the left channel of the driver's seat 91
and the mid-high-range speaker for the left channel of the passenger seat 92 72L, and the rightchannel middle-high range component SHR is supplied to the middle-high-range speaker 71R of
the driver seat 91 for the right channel and to the middle-high-range speaker 72R for the right
channel of the passenger seat 92. Ru.
[0128]
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31
Two audio signal reception distribution units 4 are provided for the driver's seat 91 and the front
passenger seat 92, and each audio signal reception distribution unit 4 receives a signal from the
audio signal output device unit 30. Thus, audio signals to be supplied to the respective speakers
61, 71L, 71R and the speakers 62, 72L, 72R may be generated.
[0129]
Of course, the audio signal output device unit 30 and the audio signal reception distribution unit
4 may be connected by wire (cable) as a wire harness instead of wireless transmission and
reception.
[0130]
[Speaker Arrangement Example of Second Embodiment] In this second embodiment, the three
speakers described above are attached to a seat of a car.
Several examples of the attachment method will be described.
[0131]
FIG. 11 is a first example of the mounting arrangement of the speakers.
FIG. 11 shows an example of mounting arrangement of speakers in the driver's seat 91, but the
same applies to the passenger's seat.
[0132]
In this example, since the headrest 911 is usually attached to the seat 91 of the car, the lowrange speaker 61 is attached in the headrest 911 without being attached to the baffle plate.
Then, in the example of FIG. 11, the left and right end portions of the headrest 911 are attached
to the left and right two-channel middle high frequency speakers 71L and 71R without being
10-05-2019
32
attached to the baffle plate.
[0133]
However, in the case of this example shown in FIG. 11, there is no problem in the passenger seat
92, but in the case of the driver's seat 91, the driver turns his head when the vehicle is to be
backed When confirming the rear, the positions of the left and right two-channel middle high
frequency speakers 71L and 71R may be in the way.
[0134]
The example of FIG. 12 is an example which improved this.
In the example of FIG. 12, the mid-high frequency speakers 71 </ b> L and 71 </ b> R are housed
in an empty space in the headrest 911.
Since the speakers 71L and 71R for the middle and high frequencies can use relatively small
speaker units, the configuration of FIG. 12 can be relatively easily realized.
[0135]
The example of FIG. 13 is also an example in which the problems of the example of FIG. 11 are
improved.
In the example of FIG. 13, the low frequency speaker 61 is mounted in the headrest 911 without
being attached to the baffle plate, but the middle high frequency speakers 71 L and 71 R are the
top of the backrest portion 912 of the seat. On both left and right shoulders, without attaching to
the baffle plate.
In this case, as shown in FIG. 13B, the mid-high range speakers 71L and 71R are attached such
that the direction of the ear of the listener 51 is the sound wave radiation direction.
10-05-2019
33
[0136]
[Configuration Example of Audio Signal Output Device Unit 3 According to Second Embodiment]
FIG. 14 is a block diagram showing a configuration example of the audio signal output device
unit 3 according to the second embodiment. The audio signal output device unit 3 in the second
embodiment also includes an audio signal processing unit 300 and a control unit 100 formed of
a microcomputer, as in the audio signal output device unit 3 in the above-described embodiment.
[0137]
The control unit 100 according to the second embodiment has the head front transfer function
storage unit 112 in addition to the head rear transfer function storage unit 111 as compared
with the control unit 100 according to the first embodiment. In addition to the provision, an
input / output port 109 is added. The other configuration of the control unit 100 is substantially
the same as that of the first embodiment.
[0138]
Further, in the audio signal processing unit 300 in the second embodiment, a switch circuit 301
for input selection is provided as in the first embodiment. However, in the second embodiment,
the input selection switch circuit 301 is supplied with the audio signal Au2 from the DVD player
2 and the audio signal Au3 from the CD player 8, and is used through the user operation
interface 110. One of the audio signals is obtained from the switch circuit 301 according to the
selection operation by the user.
[0139]
In the audio signal processing unit 300 according to the second embodiment, the 5.1 channel
decoding unit 302 is provided, and in addition to the rear transfer function convolution circuit
310 in the case of the first embodiment, the front is also provided. A transfer function
convolution circuit 320 is provided.
[0140]
Then, in the 5.1 channel decoding unit 302, when the switch circuit 301 outputs the audio signal
10-05-2019
34
Au2 from the DVD player 2 and the 5.1 channel is selected in the user operation interface 110,
Channel decoding processing is performed to output audio signals L and R for the front left and
right channels, audio signals C for the center channel, audio signals RL and RR for the rear left
and right channels, and a low frequency audio signal LFE.
[0141]
The audio signal L of the front left channel from the 5.1 channel decoding unit 302 and the
audio signal C of the center channel are synthesized by the synthesizing unit 303, and the
synthesized output audio signal (L + C) constitutes a virtual sound source processing unit. Is
supplied to a front transfer function convolution circuit 320.
Further, the sound signal R of the front right channel from the 5.1 channel decoding unit 302
and the sound signal C of the center channel are synthesized by the synthesizing unit 304, and
the synthesized output sound signal (R + C) has a front transfer function convolution. It is
supplied to the circuit 320.
[0142]
The front transfer function convolution circuit 320 has the same configuration as the rear
transfer function convolution circuit 310. For example, the head front transfer function prepared
in advance in the head front transfer function storage unit 115 using a digital filter Are
convoluted to the audio signals from the synthesis units 303 and 304.
[0143]
Therefore, in the front transfer function convolution circuit 320, when the input audio signal is
not a digital signal, it is converted into a digital signal, and the head front transfer function is
convoluted and then converted back into an analog signal and output.
[0144]
In this example, the head front transfer function is measured and determined as follows, and
stored in the head front transfer function storage unit 112.
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35
FIG. 15 is a diagram for explaining a method of measuring the head front transfer function.
[0145]
That is, as shown in FIG. 15, the left channel measurement microphone ML and the right channel
measurement microphone MR are placed in the vicinity of the left and right ears of the listener 5.
Next, the front left channel speaker 110FL is arranged in front of the listener 5 where the front
left channel speaker is usually arranged.
Then, by using the front left channel speaker 110FL, for example, the emitted sound when the
impulse is acoustically reproduced is collected by the microphones ML and MR, and from the
collected sound signal, the left and right from the front speaker 110FL are collected. Measure the
transfer function to the ear (head-to-front transfer function for the front left channel).
[0146]
Similarly, for the front right channel speaker 110FR, for example, emitted sound when the
impulse is acoustically reproduced is picked up by the respective microphones ML and MR, and
from the picked up sound signal, left and right from the front speaker 110FR Measure the
transfer function to the ear (head front transfer function for the front right channel).
[0147]
The head front transfer function is a transfer function from each speaker to the ear when the
speakers are placed at a position of 2 m, for example, at 30 degrees from the front center of the
listener 5 to the left and right of the front speakers 110FL and 110FR. It is good to measure and
obtain the transfer function obtained.
[0148]
Further supplement to the transfer function.
10-05-2019
36
For example, a transfer function coming from the left front to the left ear in FIG.
Next, a transfer function B obtained by measuring the transfer function from the speakers 71L
and 71R to the microphone ML in the vicinity of the ear is referred to as a transfer function B.
Furthermore, if a transfer function B is multiplied by a certain transfer function X, a transfer
function X which becomes a transfer function A is obtained, and the obtained transfer function X
is convoluted with the signal sound sent to the nearby speaker 71L. The sound emitted from the
speaker 71L is as if it came from the left front 2 m.
[0149]
However, the transfer function X may not necessarily be determined, and in some cases only the
transfer function A may be used. Although the above description is described on behalf of one of
the transfer functions, it is needless to say that there are actually a plurality of transfer functions,
as also shown in FIG.
[0150]
The head front transfer function measured and obtained as described above is stored in the head
front transfer function storage unit 112, and is supplied to the front transfer function
convolution circuit 320 through the input / output port 109, and the front transfer function
convolution is performed. Folded in circuit 320.
[0151]
From the front transfer function convolution circuit 320, the voice signal C of the center channel
is synthesized with the voice signal FL * of the front left channel subjected to virtual sound
source processing, and the voice signal FR * of the front right channel subjected to virtual sound
source processing Are obtained by combining the audio signal C of the center channel.
[0152]
The audio signals (FL * + C) and (FR * + C) from the front transfer function convolution circuit
320 are supplied to speakers 71, 71R or 72L, 72R disposed near both ears of the listener 51 or
52 for acoustic reproduction. Sometimes, the listener 5 listens to the reproduced audio as if the
audio was emitted from the front left and right front speakers 11FL and 11FR, and the center
channel audio is emitted from the central speaker. Listen to
10-05-2019
37
[0153]
The levels of the audio signals (FL * + C) and (FR * + C) at this time may be lower than the signal
levels supplied to the speakers 110FL and 110FR.
This is because the speakers 71L, 71R or 72L, 72R are in the vicinity of the ear of the listener 5.
[0154]
As described above, the audio signals (FL * + C) and (FR * + C) from the front transfer function
convolution circuit 320 subjected to virtual sound source processing are supplied to the
synthesis units 321 and 322.
The low-pass audio signal LFE from the 5.1 channel decoding unit 302 is supplied to the
combining units 321 and 322.
Then, the output voice signals of the synthesis units 321 and 322 are supplied to the synthesis
unit 331 and the synthesis unit 332 through the amplifiers 323 and 324.
[0155]
In addition, the audio signals RL and RR of the rear left and right 2 channels from the 5.1
channel decoding unit 302 are supplied to the rear transfer function convolution circuit 310
constituting the virtual sound source processing unit as in the first embodiment described above.
Be done.
[0156]
The head rear transfer function storage unit 111 stores the head rear transfer function measured
as described with reference to FIG. 8 in the first embodiment.
10-05-2019
38
The head rear transfer function is read out from the head rear transfer function storage unit 111
and supplied to the rear transfer function convolution circuit 310 through the input / output
port 108. The audio signals of the rear left and right two channels from the decoding unit 302
are convoluted.
[0157]
Then, the voice signal of the front left channel on which the voice signal of the center channel
has been synthesized, which has been subjected to virtual sound source processing from the
front transfer function convolution circuit 320, is low frequency band from the 5.1 channel
decoding unit 302 in the synthesis unit 321. After being synthesized with the speech signal LFE,
the speech signal LFE is supplied to the synthesis circuit 331 and synthesized with the speech
signal of the rear left channel subjected to virtual sound source processing from the rear transfer
function convolution circuit 310.
[0158]
Similarly, the voice signal of the front right channel on which the voice signal of the center
channel, which has been subjected to virtual sound source processing from the front transfer
function convolution circuit 320, is synthesized is synthesized by the synthesizing unit 322 from
the 5.1 channel decoding unit 302. After being synthesized with the low-pass speech signal LFE,
the low-pass speech signal LFE is supplied to the synthesizing circuit 332 and synthesized with
the speech signal of the rear right channel subjected to virtual sound source processing from the
rear transfer function convolution circuit 310.
[0159]
The synthesized speech signals from the synthesis circuits 331 and 332 are supplied to the
multiplexing unit 313 and multiplexed (multiplexed), and are wirelessly transmitted from the
wireless transmission unit 314 to the audio signal reception distribution unit 4.
[0160]
The audio signal reception distribution unit 4 receives radio waves from the audio signal output
device unit 3, extracts multiplexed audio signals from the received radio waves, and
demultiplexes the audio signals for the left and right two channels. Separate.
Then, from the audio signals for the left and right two channels, a signal SL supplied to the low
10-05-2019
39
band speakers 61 and 62 and signals SHL and SHR supplied to the middle high band speakers
71L and 71R and 72L and 72R are generated. , Supply to the corresponding speaker.
[0161]
Therefore, the speakers 61 and 62 mainly reproduce sound of the low-pass audio signal LFE, and
the speakers 71L, 71R and 72L, 72R are front sound signals (FL * + C) and (FR * + C) subjected to
virtual sound source processing, Also, the rear sound signals RL * and RR * subjected to virtual
sound source processing are acoustically reproduced.
[0162]
Further, when the audio signal of the left and right two channels from the CD player 8 is output
from the switch circuit 301 or when the audio signal from the DVD player 2 is an audio signal of
the left and right two channels, 5.1 channel From the decoding unit 302, only the left and right
two-channel audio signals L and R are output and supplied to the front transfer function
convolution circuit 320, where the front transfer function is convoluted and virtual sound source
processing is performed.
At this time, power is not supplied to the rear transfer function convolution circuit 310, and this
circuit 310 is inactivated.
[0163]
Then, the signals of the two channels from the front transfer function convolution circuit 320 are
supplied to the audio signal reception distribution unit 4 by the multiplexing unit 313 and the
wireless transmission unit 314 through the synthesis circuits 321, 322, 331, and 332.
[0164]
Therefore, at this time, with the speaker 61, 71L and 71R or the speaker 62, and 72L and 72R,
the audio signal obtained by performing virtual sound source processing on the audio signal of
the left and right front channels is acoustically reproduced. Sound reproduction is performed
such that sound is emitted from the front speaker placed.
[0165]
As described above, in the second embodiment, the multi-channel having a large volume and
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presence by the three speakers behind the listeners 51 and 52 near the ears of the listeners 51
and 52. While being able to enjoy sound, leakage of sound to the surroundings can be
significantly reduced, and energy saving of the sound reproduction system can be realized.
[0166]
And since each reproduction sound field is provided to each of listeners 51 and 52, in the case of
the reproduction sound field provided by the speaker fixedly installed in the dashboard of a car, a
door, etc. As described above, there is an effect that it is possible to always provide each listener
with an optimum reproduction sound field without changing the sound image localization
depending on the position of the listener.
[0167]
In addition, as described in the first embodiment, the acoustic power of the three speakers
behind the head of the listener is significantly reduced as compared to the case where the
speakers are disposed at the door or the like in the case of the conventional car audio system.
There is also an advantage that the load on the battery can be reduced because it can be done.
[0168]
In the second embodiment described above, virtual sound source processing is performed on
audio signals of all channels of multi-surround audio, and are supplied to three speakers behind
the head near the listener 5. Also in this second embodiment, for example, the voices of the left
and right front channels are reproduced by the dashboard of the car and the speakers attached
to the door, and the three speakers behind the head are the voice signals of the rear channel The
sound source processing may be performed with virtual sound source processing.
[0169]
In addition, virtual sound source processing of audio signals of all 5.1 channels, sound
reproduction with three speakers behind the head, and a center channel, which is relatively
difficult to be localized, is a dashboard of a car, A speaker provided fixedly on a door or the like
may be used to provide auxiliary information.
[0170]
[Other Embodiments or Modifications] Note that the arrangement positions of the low-range
speaker and the two middle-high range speakers are not limited to the arrangement positions in
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the above-described embodiment, and, for example, FIG. As shown in the figure, at the rear of the
listener 5, for example, if the radius is (dsw + the radius of the head of the listener 5) on the
spherical surface centering on the head of the listener 5, regardless of the position good.
However, as the arrangement position of this speaker, as shown in FIG. 16, it is desirable to be in
a section on the rear side of the face of the listener 5.
[0171]
In addition, as a method of attaching the speaker unit of the low-range speaker so that sounds
emitted from the front and back of the diaphragm can be added, it is not limited to the structure
attached to the pipe as in the above embodiment. The speaker unit for the low band is attached
to a plate having a relatively large number of holes, so that sounds emitted from the front and
back of the diaphragm can be added through the plurality of holes. It is also good.
[0172]
Moreover, in the above-mentioned embodiment, although the speaker for low-pass and the
speaker for middle-high range were fixed and attached to a chair, it is not restricted to this as a
retention form of these speakers.
For example, each of these speakers may be configured to be held one by one in the form of a
floor stand, or may be configured to be hung from a ceiling.
[0173]
Further, in the first embodiment, the target to be subjected to virtual sound source processing is
audio signals of rear left and right two channels, and in the second embodiment, audio signals of
rear left and right 2 channels and front left and right 2 channels and center channel However,
the rear left and right two channels may be acoustically reproduced by real speakers, and the
front left and right two channels and the center channel may be subjected to virtual sound source
processing.
[0174]
Further, although the above embodiment has been described for the case of a system for
reproducing 5.1 channel multi-channel audio signals, the present invention is not limited to 5.1
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42
channels, and a plurality of channels of 2 or more channels. The present invention is applicable
to all sound reproduction systems that reproduce sound signals.
[0175]
Further, it is also possible to supply an audio signal which is not subjected to the virtual sound
source processing as described above as the audio signal supplied to the low frequency range
speaker and the middle high frequency range speaker.
That is, stereo audio signals of the left and right channels may be input to the audio signal
reception and distribution unit.
[0176]
It is a figure for demonstrating the structural example of the outline | summary of 1st
Embodiment of the sound reproduction system by this invention.
It is a figure for demonstrating the speaker arrangement example in the sound reproduction
system of 1st Embodiment.
It is a figure for demonstrating the speaker arrangement example in the sound reproduction
system of 1st Embodiment.
It is a figure used for operation | movement description of embodiment of the sound
reproduction system by this invention.
It is a figure for demonstrating the speaker arrangement example in the sound reproduction
system of 1st Embodiment.
It is a figure for demonstrating the speaker arrangement example in the sound reproduction
system of 1st Embodiment.
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It is a block diagram which shows the structural example of the audio | voice signal output
apparatus part in the sound reproduction system of 1st Embodiment.
It is a figure for demonstrating the head rear transmission characteristic used for virtual sound
source processing.
It is a figure which shows the structural example of the audio | voice signal reception distribution
part of FIG.
It is a figure for demonstrating the structural example of the outline | summary of 2nd
Embodiment of the sound reproduction system by this invention. It is a figure for demonstrating
the example of a speaker arrangement | positioning in the sound reproduction system of 2nd
Embodiment. It is a figure for demonstrating the example of a speaker arrangement | positioning
in the sound reproduction system of 2nd Embodiment. It is a figure for demonstrating the
example of a speaker arrangement | positioning in the sound reproduction system of 2nd
Embodiment. It is a block diagram which shows the structural example of the audio | voice signal
output device part in the sound reproduction system of 2nd Embodiment. It is a figure for
demonstrating the head front transfer characteristic used for virtual sound source processing. It
is a figure for demonstrating the other speaker arrangement in one Embodiment of the sound
reproduction system by this invention.
Explanation of sign
[0177]
3 audio signal output device unit 4 audio signal reception distribution unit 5 listener 6 low range
speaker (first speaker) 7L, 7R middle high range speaker (second and third speakers)
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