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JP2005080079

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DESCRIPTION JP2005080079
PROBLEM TO BE SOLVED: To reproduce a target sound field in a wide band. SOLUTION: Low
frequency sound with a desired sound field is formed by a low frequency speaker system 5 to
output low frequency sound, so that low frequency sound can be generally localized in a wide
listening range. I am trying to get In addition, by delaying the high-frequency sound output from
the high-frequency speaker system 6 by a predetermined delay time, for example, the sound
image of the high-frequency sound output from the high-frequency speaker system 6 deviates
from the absolute sound image Even in this case, it is possible to make the listener perceive the
sound image of the high frequency sound at the absolute sound image position of the low
frequency sound output from the low frequency reproduction means. [Selected figure] Figure 1
Audio reproduction apparatus and audio reproduction method
[0001]
The present invention relates to an audio reproduction apparatus that reproduces an audio signal
as an audio, and an audio reproduction method.
[0002]
2. Description of the Related Art Conventionally, in a sound reproduction system using a plurality
of speakers, various sound effect techniques are known in which a target sound image
localization can be obtained at an appropriate listening position.
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1
For example, a two-channel intensity system stereo reproduction system and a multi-channel
surround system stereo reproduction system are known. Then, in the case of the stereo
reproduction system like the former, a target sound image localization can be obtained at a
predetermined listening position, that is, at a listening position where right and left speakers and
the listening position form an equilateral triangle.
[0003]
In the stereo reproduction system as described above, the reproduction sound heard by the
listener other than the appropriate listening position is largely different from the reproduction
sound heard by the listener at the predetermined listening position. That is, it is not possible to
obtain the desired sound image localization except at the proper listening position.
[0004]
Here, the points as described above will be briefly described using FIG. FIG. 5 is a diagram
showing the relationship between the arrangement position of the speaker and the binaural
response characteristic of the listener at the listening position. In FIG. 5A, two speakers (left
speaker SL and right speaker SR) are disposed on the front left and right of the listener. At this
time, the sound arriving from the two speakers SL and SR to both ears of the listener at the
listening position A, which is equidistant, can be shown as shown in FIG. 5 (b). That is, the left
sound L1 from the left speaker SL reaches the left ear of the listener at the listening position A,
and the right sound R1 from the right speaker SR reaches the right ear. In this case, the timings
of the left and right voices L1 and R1 reaching the listener's ear from the left and right speakers
become almost coincident, and the listener at the listening position A is a position near the center
of these two speakers SL and SR. It will be perceived that there is a sound image on a.
[0005]
Also, at this time, the right voice R2 from the right speaker SR reaches the left ear of the listener
at the listening position A, and the left voice L2 of the left speaker SL wraps around and reaches
the right ear. Since R2 and L2 wrap around from the left and right speakers SL and SR to reach
the listener's opposite ear, the timing to reach the listener's ear will be delayed compared to the
voice L1 and R1. .
[0006]
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2
On the other hand, the sound arriving at the listener's ears at the listening position B which is on
the right side of the listening position A shown in FIG. 5A can be shown as shown in FIG. 5C.
That is, also in this case, the left sound L1 from the left speaker SL reaches the left ear of the
listener at the listening position B, and the right sound R1 from the right speaker SR reaches the
right ear. .
[0007]
Also at this time, the right voice R2 from the right speaker SR reaches the left ear of the listener
at the listening position A, and the left voice L2 of the left speaker SL reaches the right ear. Since
these voices R2 and L2 turn around from the left and right speakers SL and SR to reach the
listener's opposite ear, the timing for reaching the listener's ear is the same as the voice L1 and
R1 as described above. It will be delayed compared to it. However, in this case, since the distance
from the left and right speakers to the listener is different, a difference occurs in the timing at
which the sounds R2 and L2 reach from the left and right speakers.
[0008]
In this case, as shown in FIG. 5A, since the listening position B is from the right speaker SR from
the listening position A, the timing of the left voice L1 reaching the left ear of the listener at the
listening position B When the timing of the right audio R1 reaching the right ear is compared
with that of the right audio R1, the timing at which the right audio R1 reaches the listener's ear is
earlier because the listening position B is closer to the right speaker SR. In this case, for the
listener at the listening position B, the sound image is localized at the position of the right
speaker SR by the preceding sound effect in which the sound image localization is obtained in the
direction of the right sound R1 arriving first. That is, the listener at the listening position B
obtains a sound image at a sound image position b different from the sound image position a
obtained by the listener at the listening position A. However, since the levels of left and right
voices reaching the listener from the left and right speakers are different, the sound image
localization as if the sound image position perceived by the listener at the listening position B
was localized to the position from the right speaker SR You will get a feeling.
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[0009]
As described above, in the speaker arrangement shown in FIG. 5A, for example, the listener at the
listening position A at an equal distance from the left and right speakers can obtain the sound
image localization at the target position, but the listening position A A listener at a listening
position B different from the above-described one sounds as if sound image localization is
obtained at a position b different from the sound image position a at the listening position A.
That is, in the conventional stereo reproduction system, a listener at a position where the
position of the listener is different from the listening position A can not obtain the sound image
localization of the target sound image position a.
[0010]
As a comparison with the speaker arrangement example shown in FIG. 5, the relationship
between the speaker arrangement position and the listener's binaural response characteristic at
the listening position is shown in FIG. In FIG. 6A, one speaker SC is disposed in the front center of
the listener. In this case, the sound C1 coming from the speaker SC can be shown as shown in
FIG. 6 (b) to the listener at the listening position A located substantially in front of the speaker
SC. That is, in this case, the sound from the speaker SC arrives at substantially the same timing
with respect to the listener's ears at the listening position A. Further, the sound image position c
in this case coincides with the position of the speaker SC.
[0011]
On the other hand, the sound coming to the listener's ears of the listening position B, which is on
the right side of the listening position A shown in FIG. 6A, can be shown as shown in FIG. 6C.
That is, in this case, the voice C1 from the speaker SC arrives first at the left ear of the listener at
the listening position B, and the voice C1 from the speaker SC arrives at the right ear with delay,
but the listening position The sound image positions obtained by the A listener and the listener at
the listening position B will both coincide at the sound image position c. That is, in this case, even
when the listening position of the listener changes, the sound image position is fixed.
[0012]
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As can be seen from FIG. 5 and FIG. 6, when the sound is output from the speaker, if the
wavefront shape from the speaker is different, the way of hearing is also different. That is, the
way of hearing differs depending on the arrangement position of the speaker and the listening
position. This is considered to be due to the fact that the sound pressure waveform transmitted
to the tympanic membrane is different when listening to the sound output from the speaker with
a three-dimensional auditory organ such as a human head or pinna, so that the way of hearing is
different. Ru.
[0013]
And conventionally, it is indicated by patent documents 1 as a method of reproducing a target
sound field by outputting a sound from a speaker. In such a patent document, by arranging the
speakers at intervals of 1/2 wavelength or less of the maximum spatial frequency of the sound
wave, the reproduced sound is diffused to the surroundings and interferes with each other, etc.
There is disclosed a technique in which a wavefront close to the original sound field is formed.
Further, in Patent Document 1, there is also a technology for collecting a voice for reproducing a
wavefront close to the original sound field when the speakers are arranged and reproduced at an
interval of 1/2 wavelength or less of the maximum spatial frequency of the sound wave. It is
disclosed.
[0014]
As a technical document related to the present invention, Patent Document 2 and Patent
Document 3 disclose a technology for adding a delayed signal to compensate for the sense of
volume without changing the position of the sound image perceived by the listener. There is.
However, in these patent documents 2 and patent document 3, examination about reproduction
of a wave face is not carried out.
[0015]
JP-A-2-114799 JP-A-9-149500 JP-A-10-243500
[0016]
However, in the reproduction device disclosed in Patent Document 1, it is necessary to set the
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distance between the speakers to 1/2 wavelength or less of the maximum reproduction
frequency (maximum spatial frequency) of the sound field to be reproduced.
For this reason, in order to reproduce the sound field over a wide band from a low frequency
range of several tens Hz to a high frequency range of several tens kHz, it is necessary to arrange
a large number of speakers at narrow intervals. For example, in order to reproduce a sound field
by reproducing 17 kHz sound by a speaker, it is necessary to arrange the speakers at intervals of
1 cm, and it is impossible to arrange the speakers actually. Therefore, in the reproducing
apparatus as disclosed in Patent Document 1 described above, it is difficult to output a sound
wave in a wide frequency band from low to high frequencies with one wave front, and a wideband sound including high frequencies It has the problem that the field can not be reproduced.
[0017]
Then, this invention is made in view of such a subject, and an object of this invention is to
provide the audio | voice reproduction apparatus and the audio | voice reproduction method
which can reproduce the sound field of the target wideband | broadband.
[0018]
In order to achieve the above object, the audio reproducing apparatus of the present invention is
configured to reproduce and output low-pass audio that is audio having a predetermined
maximum frequency or less by forming an acoustic wave surface that reproduces a target sound
field. Low-pass audio reproduction means, high-pass audio reproduction means included in a
sound source having low-pass speech as a band component, and reproducing and outputting
high-pass speech including frequency components higher than the maximum frequency of lowpass speech; The reproduction output timing control means is provided to reproduce and output
the high frequency sound reproduced and outputted from the low frequency sound reproduction
means at a timing delayed for a predetermined time with respect to the low frequency sound
reproduced and outputted.
[0019]
Further, according to the audio reproduction method of the present invention, a low-pass audio
reproduction procedure for reproducing and outputting low-pass audio that is audio below a
predetermined maximum frequency so as to form a sound wave surface that reproduces a target
sound field. A high frequency sound reproduction procedure for reproducing and outputting high
frequency sound including low frequency sound as a band component and including high
frequency components including frequency components higher than the maximum frequency of
low frequency sound, and high sound reproduced and output from high frequency sound
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reproduction means The reproduction output timing control procedure is performed to
reproduce and output the low-frequency sound to the low-frequency sound reproduced and
output from the low-frequency sound reproduction means at a timing delayed by a
predetermined time.
[0020]
According to the above-described configuration, the desired sound field is reproduced in a wide
listening range for the low frequency sound by reproducing the low frequency sound lower than
the predetermined frequency so that the sound wave surface reproducing the intended sound
field is formed. At the same time, the high frequency sound from the same sound source as the
low frequency sound is delayed by the delay means and reproduced by the delay means, and the
low frequency sound is heard for the listener within the range where the low frequency sound
can be heard. It becomes possible to cause the sound image position of the sound field to be
reproduced to perceive the sound image of high-pass sound.
[0021]
According to the present invention as described above, a desired sound field is reproduced in a
wide listening range for low-pass speech, and high-pass speech from the same sound source as
this low-pass speech is delayed and reproduced from low-pass speech. Thus, for a listener in the
range where low-pass speech can be heard, the sound image position of the high-pass speech can
be perceived at the sound image position of the sound field reproduced by the low-pass speech. A
broadband sound field can be reproduced.
[0022]
Hereinafter, embodiments of the present invention will be described.
In the present embodiment, an AV system having a function as an audio reproduction apparatus
of the present invention will be described as an example.
FIG. 1 is a view showing an arrangement example of speakers in the AV system of the present
embodiment.
FIG. 1 is a view of the AV system 1 of the present embodiment as viewed from the top side.
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7
[0023]
In the AV system 1 shown in FIG. 1, a screen 2 and a front projection type projector 3 for
displaying an image on the screen 2 are provided.
In this case, the low frequency speaker system 5 and the high frequency speaker system 6 are
provided on the back side of the screen 2, and the ultra low frequency speaker (subwoofer) 8 is
disposed at the center of the front surface of the screen 2. There is.
Further, in such an AV system 1, the broadband speaker system 7 is disposed on the back side of
the viewer U (U 1, U 2, U 3).
[0024]
The low frequency speaker system 5 constituting the low frequency sound reproducing means is,
for example, a plurality of low frequency speakers 5-1, 5-2 ... that can reproduce low to midrange sound of several tens Hz to 3 kHz. Configured by an array. The plurality of low frequency
range speakers 5-1, 5-2... Are arranged at intervals L (L indicates a distance (length)). The
interval L between the low-range speakers 5-1, 5-2, ... is determined by the maximum
reproduction frequency (maximum spatial frequency) of the reproduced sound reproduced by
the low-range speakers 5-1, 5-2, ... The length may be half or less of the wavelength λ. Also, the
interval L does not have to be constant. For example, in the case where the low to high frequency
range is reproduced with the maximum reproduction frequency of the low range speakers 5-1, 52... As 3 kHz, the low range speakers 5-1, 5-2. It may be arranged at intervals of 6 cm or less. In
practice, the arrangement interval of the speakers, that is, the maximum reproduction frequency
of the speakers may be determined in consideration of the size and the like of the low-range
speakers 5-1, 5-2, and so on.
[0025]
Furthermore, FIG. 1 shows that the low band speakers 5-1, 5-2... Of the low band speaker system
5 are arranged in the left and right direction of the screen 2 at a constant interval L, When the
low frequency range speakers are arranged in the vertical direction of the screen 2 as well, the
speakers may be arranged at an interval L or less.
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[0026]
The high-frequency speaker system 6 constituting the high-frequency sound reproducing means
is constituted by three high-frequency speakers 6-1, 6-2, 6-3 capable of reproducing highfrequency sound of, for example, 3 kHz or more. Region speakers 6-1, 6-2, and 6-3 are disposed
on the rear left side, rear center, and rear right side of the screen 2, respectively.
In the example shown in FIG. 1, the high frequency speaker system 6 is configured by the three
high frequency speakers 6-1, 6-2, 6-3, but this is merely an example, and the high frequency
speaker system 6 The speaker system 6 is preferably configured using more speakers.
[0027]
The wide-band speaker system 7 includes, for example, two wide-band speakers 7-1 and 7-2
capable of reproducing wide-band sound of several tens Hz to several tens kHz. In order to
realize surround reproduction in the AV system 1 shown in FIG. 1, the broadband speaker system
7 is disposed on the broadband speakers 7-1 and 7-2 on the rear right and left sides of the
viewer U, respectively, to surround sound in the rear direction. It is made to output.
[0028]
The ultra low range speaker 8 is configured of a speaker capable of reproducing ultra low range
audio of, for example, 200 Hz or less, and is disposed, for example, in the front direction of the
viewer U. Such an ultra low frequency range speaker 8 is also provided to realize surround
reproduction in the AV system 1 shown in FIG. For example, it is arranged in the front direction
of the viewer U.
[0029]
As described above, in the AV system 1 of the present embodiment, as described above, the
arrangement interval L of the low-range speakers 5-1, 5-2,. The speakers 5-1, 5-2, and so on are
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9
set to 1/2 or less of the wavelength determined by the maximum reproduction frequency
(maximum spatial frequency) that can be reproduced. Then, low-frequency sounds corresponding
to the sound field to be reproduced are output from the low-frequency speakers 5-1, 5-2, and so
on.
[0030]
In this case, the low frequency sound outputted from the low frequency speakers 5-1, 5-2 ... of
the low frequency speaker system 5 is surrounded by the low frequency speakers 5-1, 5-2 ... ,
And interfere with each other to be combined to form one wavefront in total. And, by forming
one sound wave surface in this way, it is possible to reproduce the intended sound field. When
the sound field is reproduced in this manner, it is possible to expand the listening range in which
the sound image position is heard at the same position.
[0031]
The low frequency sound outputted from the low frequency speakers 5-1, 5-2, ... of the low
frequency speaker system 5 reproduces a target sound field when the low frequency sounds are
synthesized. It can be any low-frequency voice that can be played. For example, the sound
collected by the technique disclosed in the above-mentioned Patent Document 1, that is, the
microphones are disposed at the same interval L as the low-range speakers 5-1, 5-2, ... of the lowrange speaker system 5 and collected. It is conceivable to use low-pass sound that is obtained by
sounding. Alternatively, Takeda et al., "Study on wave-field synthesis using multi-channel speaker
reproduction", Proceedings of the Acoustical Society of Japan, Sept. 2000, p. 407-408. It is
conceivable to create a signal and use low-pass speech created using this low-pass speech signal.
[0032]
On the other hand, the high-frequency speaker system 6 outputs high-frequency sound whose
sound image position is controlled by, for example, operating the ratio of the output level of each
high-frequency speaker 6-1 to 6-3. However, as in the low band speakers 5-1, 5-2, and so on, the
speakers are not arranged at a distance interval within a half wavelength of the maximum
frequency. For this reason, in the case of high-pass speech, unlike the low-pass speech, it is not
possible to form a wavefront for reproducing a target sound field.
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[0033]
However, in the AV system 1 of the present embodiment, the reproduction timing of the highfrequency sound reproduced from the high-frequency speaker system 6 is several millimeters
from the reproduction timing of the low-frequency sound reproduced from the low-frequency
speaker system 5 The output is delayed by several seconds to several tens of milliseconds.
However, the delay time at this time is set within a time when the high frequency sound to be
reproduced later is not audible to the viewer U as echo sound of the low frequency sound (echo
sound). .
[0034]
As described above, in the AV system 1 of the present embodiment, the low-range speakers 5-1,
5-2... Of the low-range speaker system 5 are replaced with the low-range speakers 5-1, 5-2. The
low frequency range to be reproduced from each of the low frequency range speakers 5-1, 5-2,
etc. after being set to 1/2 or less of the wavelength λ determined by the maximum spatial
frequency that can be reproduced. By reproducing the sound, the low-frequency sound
reproduces the target sound field in a wide listening range. In addition, the reproduction timing
of the high frequency sound reproduced from the high frequency speaker system 6 is delayed by
a predetermined delay time from the reproduction timing of the low frequency sound reproduced
from the low frequency speaker system 5. As a result, in the AV system 1 of the present
embodiment, it is possible to reproduce the target sound field over the wide band from the low
band to the high band, for the reason described below.
[0035]
As a result of investigations by the inventors of the present invention, when sounds originating
from the same sound source are divided into bands, and sounds divided into these bands are
output from different positions, the divided bands It has been found that the sound source is
located at the position where the voice of the band component that has come to the ear first is
output as the human auditory sense when the time difference is given to the sound and the
sound is outputted. That is, it has been found that the sound of the delayed frequency component
output from another position can also be heard as being localized at the output position of the
audio of the band component that has come to the ear first. . That is, for example, when the
sound originating from the same sound source is divided into the low frequency component and
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the high frequency component and output, if the low frequency component is output earlier in
time, this low frequency component The sound of 決定 determines the sound field as its sound
source.
[0036]
Then, in the description with reference to FIG. 1, the wave front is formed so that the target
sound source is reproduced by the low frequency component, and the high frequency component
is delayed with respect to the low frequency component. By outputting, the high frequency
components reach the viewer's ear later than the low frequency components. As a result, for the
human sense of hearing, high frequency components can be heard at the same low position as
low frequency components. That is, in the human sense of hearing, the high-frequency sound
output from the high-frequency speaker can be heard as if the sound field is being reproduced
similarly to the low-frequency sound output from the low-frequency speaker. As a result, it is
possible to obtain the same way of sound generation as in the wavefront formation for
reproducing the target sound field over the low band to the high band.
[0037]
Therefore, even if the target sound field is not reproduced by the high band sound reproduced
from the high band speaker system 6, the sound field is reproduced by the low band sound
reproduced from the low band speaker system 5, The target sound field can be reproduced by
delaying and outputting the high band voice to the low band voice within a range in which the
viewer U can not hear the echo sound.
[0038]
Hereinafter, a configuration example for realizing the AV system 1 as described above will be
described.
First, an example data structure of a recording medium used as a sound source in the AV system
1 as described above will be described. Note that video data, subtitle data, and audio data are
multiplexed and recorded on the recording medium. In this case, as the audio data to be recorded
in the recording medium, the low-range speakers 5-1, 5-2, ... of the low-range speaker system 5
described above, and the high-range speaker system 6 Sound data of so-called wavefront
reproduction system corresponding to the speakers 6-1 to 6-3, and surround corresponding to
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the wide band speakers 7-1 and 7-2 and the ultra low band speaker 8 of the wide band speaker
system 1, respectively. It is assumed that audio data of the reproduction system is multiplexed
and recorded.
[0039]
FIG. 2 is a diagram schematically showing the data structure. As shown in FIG. 2A, in the
recording medium, for example, a pack consisting of a video packet, a subtitle packet, a plurality
of audio packets 1, an audio packet 2,. Pack header is added. The pack header is given, for
example, additional information serving as a reference at the time of synchronous reproduction.
[0040]
As shown in FIG. 2 (b), the voice packet is composed of a plurality of voice channels 1, voice
channel 2 ... voice channel n, and a packet header is added at the head. For example, various
control data used for voice control are recorded in the packet header. For example, a sampling
frequency, the number of multiplexed channels, a crossover frequency, a data coding system
code representing a data coding system, and an audio signal specification code representing a
specification (format) of an audio signal reproduction system are recorded. Further, in the audio
signal specification code, information such as a format of audio data, for example, a reproduction
method (wavefront reproduction method / intensity control method), a speaker interval, and a
speaker arrangement are recorded.
[0041]
In each audio channel, as shown in FIG. 2 (c), a channel header is added to the head of data. In
the channel header, for example, data indicating a channel number, a frequency band, a gain, and
a phase amount are recorded as additional information.
[0042]
FIG. 3 is a block diagram showing the configuration of the AV system 1 described above. In FIG.
3, the optical disc drive unit 10 reads out multiplexed data recorded on the optical disc. The
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demultiplexing circuit 11 is configured to detect and separate a header, video data, subtitle data,
and audio data of a plurality of channels from the read multiplexed data.
[0043]
The audio data decoding circuit 12 decodes audio data transmitted from the demultiplexing
circuit 11. Further, the audio data decoding circuit 12 adjusts the phase and amplitude level of
the decoded audio data and outputs the result to the audio reproduction unit 20. At this time, the
audio data decoding circuit 12 outputs wideband frequency data of the decoded audio data to the
wideband frequency reproducing circuit 21 and outputs ultra-low frequency data to the ultra-low
frequency reproducing circuit 23. . The low frequency data is output to the low frequency
recovery circuit 25 and the high frequency data is output to the high frequency recovery circuit
27.
[0044]
The subtitle data decoding circuit 13 decodes subtitle data from a subtitle packet in accordance
with timing information included in header information transmitted from the demultiplexing
circuit 11 and outputs the subtitle data. Further, the video data decoding circuit 14 decodes and
outputs the video data in accordance with the frame rate included in the header information
transmitted from the demultiplexing circuit 11 as described above.
[0045]
The subtitle reproduction circuit 15 performs required reproduction processing on the subtitle
data decoded by the subtitle data decoding circuit 13 and outputs the subtitle data as a subtitle
signal. The video reproduction circuit 16 performs predetermined reproduction processing on
the video data decoded by the video data decode circuit 14 and outputs the video data as a video
signal.
[0046]
The subtitle / superimpose circuit 17 superimposes a subtitle signal on a video signal based on
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timing information such as subtitle control information recorded as header information in a
packet header added to a subtitle packet. A pause process is performed to convert into a video
signal format according to the video display unit 18 and output. The video display unit 18 is
configured to display a video based on the video signal supplied from the subtitle / superimpose
circuit 17.
[0047]
The wide band frequency reproduction circuit 21 performs signal processing such as gain
adjustment on a plurality of wide band frequency data supplied from the audio data decoding
circuit 12 based on the control of the control unit 31 and converts the signal into an analog
signal. It is output to the wide band frequency amplification circuit 22 as a wide band frequency
signal.
[0048]
The wide band frequency amplification circuit 22 amplifies the wide band frequency signal from
the wide band frequency recovery circuit 21 to a predetermined level, and outputs the amplified
wide band frequency signal to the wide band speaker system 7. The wide band speakers 7-1 and
7-2 of the wide band speaker system 7 Will be output from
[0049]
The ultra low frequency reproduction circuit 23 performs signal processing such as gain
adjustment on the ultra low frequency data supplied from the audio data decoding circuit 12
based on the control of the control unit 31, and then performs an ultra low frequency operation.
The signal is output to the very low frequency frequency amplification circuit 24 as a signal.
The ultra low frequency frequency amplification circuit 24 amplifies the ultra low frequency
signal to a predetermined level and outputs the amplified signal from the ultra low frequency
speaker 8.
[0050]
The low frequency reproduction circuit 25 subjects each of the plurality of low frequency data
supplied from the audio data decoding circuit 12 to signal processing such as gain adjustment
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based on the control of the control unit 31, and then an analog signal. And output to the low
frequency amplification circuit 26 as a low frequency signal.
The low frequency frequency amplification circuit 26 amplifies the low frequency signal from the
low frequency reproduction circuit 25 to a predetermined level and outputs the amplified low
frequency signal to the low frequency speaker system 5 for each low frequency of the low
frequency speaker system 5. .. Are output.
[0051]
The high frequency reproduction circuit 27 performs signal processing such as gain adjustment
on each of the plurality of high frequency data supplied from the audio data decoding circuit 12,
and then converts it into an analog high frequency signal and performs timing. It is output to the
delay circuit 28 which is control means.
[0052]
The delay circuit 28 delays the high frequency signal from the high frequency reproduction
circuit 27 by the set delay time and outputs the delayed high frequency signal to the high
frequency amplification circuit 29.
The high frequency amplification circuit 29 amplifies the high frequency signal from the high
frequency reproduction circuit 27 delayed by the predetermined delay time by the delay circuit
28 to a predetermined level and outputs the amplified signal to the high frequency speaker
system 6. The high frequency speakers 6-1, 6-2, and 6-3 of the high frequency speaker system 6
output the signal.
[0053]
The control unit 31 controls the entire AV system 1 and performs various types of control using
header information and the like separated from multiplexed data by the demultiplexing circuit
11. For example, switching control for switching the operation of the audio data decoding circuit
12 is performed based on the sampling frequency added to the packet header shown in FIG. 2
and the data encoding method code. Further, from the audio signal specification (format) code
similarly added to the packet header, only the audio packet that matches the specification of the
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audio reproduction unit 20 is selected. If the voice packet 1 is a wavefront playback voice packet,
the voice packet 2 is an intensity control voice packet, and the voice packet 3 is a surround
playback voice packet, the corresponding voice packet 1 and voice packet 3 are selected. To be
[0054]
Further, when the number of audio channels included in the audio packet does not match the
number of arranged speakers depending on the size of the screen 2 and the size of the listening
room, the control unit 31 determines the packet header or the channel. From the header
information of the header, the necessary audio channel is selected according to the number of
loudspeakers actually arranged, that is, to suit the playback environment. Then, the audio data of
each audio channel is transmitted to the corresponding reproduction circuit, that is, the wide
band frequency reproduction circuit 21, the very low frequency reproduction circuit 23, the low
frequency reproduction circuit 25, and the high frequency reproduction circuit 27 according to
the channel number of the channel header. In order to control.
[0055]
Also, the control unit 31 causes the audio data decoding circuit 12 to execute phase control
based on data indicating gain and phase amount among data recorded in the channel header, and
each reproduction circuit, wideband frequency reproduction In the circuit 21, the very low
frequency reproduction circuit 23, the low frequency reproduction circuit 25, and the high
frequency reproduction circuit 27, gain adjustment and the like are performed. The phase control
can also be performed in each reproduction circuit.
[0056]
Therefore, if the AV system 1 is configured in this manner, high-frequency sound output from the
high-frequency speaker system 6 can be output from the low-frequency speaker system 5 based
on the audio data recorded on the recording medium such as an optical disk. Since it is possible
to delay and output the low-frequency sound output from the low-frequency speaker system 5, it
is possible to reproduce a target wide-band sound field over a wide band from low to high
frequencies.
[0057]
In the AV system 1 of the present embodiment shown in FIG. 3, the high frequency signal is
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delayed using the delay circuit 28 as the timing control means, but this is merely an example, for
example, a packet header Even if the high frequency sound output from the high frequency
speaker system 6 is delayed more than the low frequency sound output from the low frequency
speaker system 5 due to the decoding time stamp of the audio data added to the good.
[0058]
Further, in the low frequency reproduction circuit 25 and the high frequency reproduction
circuit 27, the reproduction timing of the low frequency signal and the high frequency signal is
determined according to the positional relationship between the low frequency speaker system 5
and the high frequency speaker system 6. The high frequency sound may be delayed more than
the low frequency sound by adjustment or the like.
[0059]
By the way, in the AV system 1 shown in FIG. 3 above, low-pass frequency data corresponding to
the low-pass speaker system 5 as sound data of the wavefront reproduction system at least on
recording media such as an optical disc Although the high frequency data corresponding to 6 is
described as being multiplexed, this is merely an example.
For example, it is possible to record audio data which has not been divided into bands on a
recording medium.
[0060]
The block configuration of the AV system in that case can be shown in FIG.
The same blocks as in FIG. 3 are assigned the same reference numerals and detailed explanations
thereof will be omitted.
In the AV system shown in FIG. 4, as shown in the figure, the frequency between the audio data
decoding circuit 12 and the very low frequency reproduction circuit 23, the low frequency
reproduction circuit 25, and the high frequency reproduction circuit 27 is It differs from the AV
system 1 shown in FIG. 3 in that the band separation circuit 41 is provided.
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[0061]
In such a frequency band separation circuit 41, the wide band frequency data read from the
optical disc and decoded by the audio data decoding circuit 12 is separated into high frequency
data and low frequency data. Then, the high frequency data and low frequency data separated by
the frequency band separation circuit 41 in this manner are supplied to the ultra low frequency
reproduction circuit 23, the low frequency reproduction circuit 25, and the high frequency
reproduction circuit 27. . At this time, the low frequency reproduction circuit 25 controls the
phase and level of the low frequency data separated from the wide band frequency data, and low
frequency sound for reproducing the target sound field from the low frequency speaker system 5
Low frequency data can be generated by signal processing.
[0062]
In the AV system of the present embodiment, various data to be reproduced are described as
video data, subtitle data, and audio data of a plurality of audio channels being multiplexed and
recorded in a recording medium such as an optical disc. However, for example, it is possible to be
configured to be able to receive data to be reproduced, such as video data, subtitle data, audio
data of a plurality of audio channels, etc., via a network line. Further, the recording medium is not
limited to the optical disc, and it is needless to say that a Blu-ray disc, for example, may be used.
[0063]
Further, in the present embodiment, the AV system including the audio reproduction device of
the present invention has been described as an example, but the audio reproduction device of the
present invention reproduces at least low frequency signals to obtain low frequency sound. It is
equipped with low band audio reproduction means to output, high band audio reproduction
means to reproduce high band frequency signal and outputs high band speech, and delay means
capable of delaying high band speech from low band speech and outputting It is considered good
if it
[0064]
Further, in the present embodiment, although the low frequency speaker system has been
described as being configured by a speaker array combining a plurality of low frequency
speakers, this is merely an example, and the low frequency speaker system is reproduced The
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configuration may be any configuration as long as it can combine the wave fronts of sound waves
from which absolute sound image localization can be obtained. For example, it is possible to
configure using nondirectional spherical speakers or single speakers. .
[0065]
It is a figure showing an example of arrangement of a speaker in an AV system of this
embodiment.
It is the figure which showed an example of the data structure multiplexed from the sound
source.
FIG. 1 is a block diagram showing a configuration of an AV system according to an embodiment
of the present invention. It is a block diagram showing other composition of AV system of this
embodiment. It is the figure which showed the relationship between the arrangement |
positioning position of a speaker, and the binaural response characteristic of the listener in the
listening position. It is the figure which showed the relationship between the arrangement |
positioning position of a speaker, and the binaural response characteristic of the listener in the
listening position.
Explanation of sign
[0066]
1 AV system, 2 screens, 3 projection type projectors, 4 listeners, 5-15-25-3 ..... low frequency
speakers, 5 low frequency speaker systems, 6-1 to 6-3, high frequency Speaker, 6 high frequency
speaker system, 7-1 7-2 wide band speaker, 7 wide band speaker system, 8 ultra low frequency
speaker, 10 optical disk drive unit, 11 inverse multiplexing circuit, 12 audio data decoding
circuit, 13 subtitle data decoding circuit 14 video data decoding circuit 15 subtitle reproduction
circuit 16 video reproduction circuit 17 subtitle / superimpose circuit 18 video display unit 20
audio reproduction unit 21 wideband frequency reproduction circuit 22 wideband frequency
Amplifier circuit, 23 ultra low frequency frequency recovery circuit, 24 ultra low frequency
frequency amplification circuit, 25 low frequency frequency recovery circuit, 26 low frequency
frequency amplification circuit, 7 high-frequency reproducing circuit, 28 delay circuit, 29 highfrequency amplifier circuit, 31 control unit, 41 a frequency band separation circuit
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