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JP2008147839

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DESCRIPTION JP2008147839
PROBLEM TO BE SOLVED: To provide a new and improved sound field reproducing device, an
audio signal generating device, and a sound field reproducing method capable of transmitting
enhanced bass without causing spatial interference to the entire listening area of a listener And
providing computer programs. SOLUTION: An amplification unit for amplifying low frequency
audio information which is information of a frequency domain equal to or lower than a
predetermined frequency included in audio information and generating amplified low frequency
audio information, audio information, amplified low frequency audio information, An audio signal
generation device is provided that includes an audio signal generation unit that generates an mchannel audio signal for forming a virtual sound source by wavefront synthesis using sound
source position information. [Selected figure] Figure 2
Audio signal generating device, sound field reproducing device, audio signal generating method
and computer program
[0001]
The present invention relates to an audio signal generation device, a sound field reproduction
device, an audio signal generation method, and a computer program.
[0002]
A stereo reproduction system is widely known which reproduces multi-channel audio signals
using a plurality of speakers in order to reproduce realistic sounds.
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1
For example, a 5.1 channel surround system uses five speakers and one subwoofer speaker to
play sound. Arrange the speakers according to the provisions of ITU-R BS 775 (International
Telecommunication Union Radiocommunications Sector), and different sound waves are output
from the speakers corresponding to each channel, and the listener hears the listener, making the
listener feel more realistic You can enjoy some sounds.
[0003]
A stereo reproduction system such as a 5.1 channel surround system can obtain a target sound
image localization at a predetermined listening position. However, since such a stereo
reproduction system has a narrow range in which the target sound image localization can be
obtained, the reproduction sound heard by the listener is heard at the predetermined listening
position at a place other than the predetermined listening position. Compared to the playback
sound.
[0004]
Therefore, there is a multi-channel audio system that aims to physically reproduce in space the
sound field itself in which the original sound source existed. A multi-channel audio system uses
wavefront synthesis technology, which is one of sound synthesis techniques, and reproduces a
sound field by outputting sound waves from an array speaker consisting of a plurality of
speakers. The sound wave output from the array speaker is transmitted to the listener as a wave
without interference. By hearing the sound wave, the listener can enjoy a realistic sound.
[0005]
Also, the multi-channel audio system virtually arranges sound sources and synthesizes
wavefronts so that sound is emitted from the arranged sound sources, so that the listener is as if
sounds are emitted from that location You can enjoy the realistic sound as if you were there.
[0006]
FIG. 10 is an explanatory view schematically showing a wavefront from a sound source.
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(A) of FIG. 10 schematically represents a wave front at the time of outputting a sound from one
sound source (speaker), and (b) of FIG. It represents. As shown in (b) of FIG. 10, by controlling
the timing and level of the sound emitted from each speaker, it is possible to generate a
wavefront as if sound is being emitted from one sound source. it can.
[0007]
Such a multi-channel audio system has a wider range of obtaining target sound image
localization than a stereo reproduction system. Therefore, more listeners can enjoy a realistic
sound in a large room.
[0008]
FIG. 11 is an explanatory view for explaining a case where wavefronts from two sound sources
are reproduced by wavefront synthesis. As shown in FIG. 11, the wavefront emitted from an
arbitrary position of the sound field can be reproduced by the sound emitted from the array
speaker by using the wavefront synthesis technique.
[0009]
By using the wavefront synthesis technology, as described above, the wavefront emitted from any
position of the sound field can be reproduced, so that the listener can enjoy a more realistic
sound field. FIG. 12 is an explanatory diagram for explaining the difference in the listening image
between the stereo method and the multi-channel audio system. (A) of FIG. 12 shows listening
images (sound images) of five virtual sound sources by stereo system, and (b) of FIG. 12 shows
listening images (sound images) of five virtual sound sources by multi-channel audio system
There is.
[0010]
As shown in FIG. 12 (a), according to the stereo system, a desired sound field can not be
reproduced unless the listener is positioned at the center between the left and right speakers SPL
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and SPR. The sound image could only be obtained as being disposed on the line between the left
and right speakers SPL, SPR. On the other hand, as shown in (b) of FIG. 12, according to the
multi-channel audio system, the sound field formed by the sound emitted from the m speakers
SP1, SP2,. The desired sound field can be reproduced in a wider range than in the case, and
furthermore, the sound source can be arranged at any position including the depth direction, and
the sound image can be perceived as such. Therefore, the listener can enjoy a more realistic
sound field by arranging the sound source at an arbitrary position according to the image
displayed on the monitor MO.
[0011]
When reproducing a sound using a multi-channel audio system, position information for virtually
arranging a sound source in sound source data as a basis of the reproduced sound and a
configuration of an assumed system, for example, an array speaker Information on the number of
speakers and the expected listening position of the listener is included in advance. Then, by
reproducing the sound based on the information contained in the sound source data in the multichannel audio system, it is possible to express a realistic sound (see Patent Document 1).
[0012]
JP, 2005-167612, A
[0013]
In multi-channel audio systems, small diameter speakers are generally used for array speakers.
FIG. 13 is an explanatory diagram for explaining frequency characteristics of a general smallaperture speaker. As shown in FIG. 13, the amplitude of the small-aperture speaker starts to drop
at about 150 Hz, and the level decreases by about −10 dB around 70 to 80 Hz. Thus, the small
diameter speaker can not reproduce the low range sufficiently. Therefore, the multi-channel
audio system which forms a virtual sound source by wave field synthesis has a problem that the
bass part can not be reproduced sufficiently for the entire listening area of the listener.
[0014]
Therefore, the present invention has been made in view of the above problems, and an object of
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the present invention is to provide a new and improved system capable of transmitting enhanced
bass to the entire listening area of a listener. An audio signal generation device, a sound field
reproduction device, an audio signal generation method, and a computer program are provided.
[0015]
To solve the above problems, according to one aspect of the present invention, audio data
including audio information and sound source position information is input, and audio is output
from an array speaker consisting of m speakers arranged in an array. An audio signal generation
device for generating an audio signal for reproducing a sound field consisting of a virtual sound
source arranged in a virtual space to a listening area including a supposed listening area of a real
space by performing: And an amplification unit for amplifying low frequency audio information
which is information of a frequency region lower than a predetermined frequency and generating
amplified low frequency audio information; and a wavefront using audio information, amplified
low frequency audio information and sound source position information An audio signal
generation device is provided, including: an audio signal generation unit that generates an mchannel audio signal for forming a virtual sound source by synthesis.
[0016]
According to this configuration, the amplification unit amplifies low-frequency audio information
that is information in a frequency domain below a predetermined frequency included in the
audio information to generate amplified low-frequency audio information, and the audio signal
generation unit generates the audio information The amplified low-frequency sound information
and the sound source position information are used to generate m channel sound signals for
forming a virtual sound source by wave-field synthesis.
As a result, it is possible to generate an audio signal for forming a virtual sound source by
wavefront synthesis in which the low frequency region is enhanced.
[0017]
The audio signal generation apparatus further includes a low frequency component separation
unit for separating low frequency audio information lower than a predetermined level from the
original audio information, and the amplification unit generates low frequency audio information
separated by the low frequency component separation unit. May be amplified to generate
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amplified low frequency speech information.
According to this configuration, the low frequency component separation unit separates the low
frequency audio information lower than the predetermined level from the original audio
information, and the amplification unit amplifies the low frequency audio information separated
by the low frequency component separation unit. Generate amplified low frequency speech
information. As a result, by separating the low frequency audio information from the original
audio information, it is possible to generate an amplified low frequency audio signal for forming
a virtual sound source by wavefront synthesis in which the low frequency region is amplified.
[0018]
The audio signal generation device may further include a low frequency sound source position
information calculation unit that calculates low frequency sound source position information that
is information on the arrangement position of the low frequency virtual sound source including
the amplified low frequency sound information. According to this configuration, the low
frequency sound source position information calculation unit calculates low frequency sound
source position information which is information on the arrangement position of the low
frequency virtual sound source including the amplified low frequency sound information. As a
result, the low frequency virtual sound source including the amplified low frequency sound
information can be arranged separately from the other virtual sound sources.
[0019]
The low frequency sound source position information calculation unit is configured such that the
arrangement position of the low frequency virtual sound source including the amplified low
frequency sound information is the curvature radius of the wave front of the sound output from
the low frequency virtual sound source It may be calculated to be larger than the curvature
radius of the wavefront. According to this configuration, the low frequency sound source position
information calculation unit is configured such that the arrangement position of the low
frequency virtual sound source including the amplified low frequency sound information is the
curvature radius of the wave front of the sound output from the low frequency virtual sound
source It is calculated so as to be larger than the curvature radius of the wavefront of the sound
output from. As a result, the number of speakers that output the sound from the low frequency
virtual sound source increases, and a larger low-pass enhancement effect can be obtained.
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[0020]
The low frequency sound source position information calculation unit may calculate so that the
arrangement position of the low frequency virtual sound source including the amplified low
frequency sound information is on the center line of the array speaker. According to this
configuration, the low frequency sound source position information calculation unit calculates
the arrangement position of the low frequency virtual sound source including the amplified low
frequency sound information to be on the center line of the array speaker. As a result, it is
possible to reproduce a sound field in which the sound in the low frequency area is uniformly
enhanced in the listening area including the assumed listener position.
[0021]
The low frequency sound source position information calculation unit may calculate so that the
arrangement position of the low frequency virtual sound source including the amplified low
frequency sound information is in the vicinity of the virtual sound source emitting the largest low
frequency sound. According to this configuration, the low frequency sound source position
information calculation unit calculates so that the arrangement position of the low frequency
virtual sound source including the amplified low frequency sound information is in the vicinity of
the virtual sound source emitting the largest low frequency sound. As a result, it is possible to
reproduce a sound field in which the sound in the low frequency region from the virtual sound
source emitting the largest low frequency sound is enhanced.
[0022]
The audio signal generation device further includes a low frequency audio signal generation unit
for generating an m channel low frequency audio signal for forming a virtual sound source by
wavefront synthesis using amplified low frequency audio information and low frequency sound
source position information. It may be. According to such a configuration, the low frequency
audio signal generation unit generates an m-channel low frequency audio signal for forming a
virtual sound source by wavefront synthesis using the amplified low frequency audio information
and the low frequency sound source position information. As a result, each of the m speakers
outputs low frequency sound by the low frequency sound signal, and wavefront synthesis is
performed by the output low frequency sound to form a virtual sound source.
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[0023]
The predetermined frequency may be 150 Hz. As a result, even if the amplification amount in the
low frequency region of each speaker constituting the array speaker is not large, it is possible to
enhance the bass feeling in the entire array speaker.
[0024]
In order to solve the above problems, according to another aspect of the present invention, audio
data including audio information and sound source position information is input, and from an
array speaker consisting of m speakers arranged in an array. A sound field reproducing
apparatus which reproduces a sound field consisting of a virtual sound source arranged in a
virtual space to a listening area including an assumed listener position of a real space by
outputting a sound, wherein: Amplifier that amplifies low-frequency audio information that is
information in the frequency domain below the frequency of f, and generates amplified lowfrequency audio information; and virtual using wavefront synthesis using audio information,
amplified low-frequency audio information, and sound source position information An audio
signal generation unit for generating an audio signal of m channels to form a sound source; and
wave combining an audio signal of m channels and outputting an audio of m channels to perform
listening including the assumed listener position An audio output unit for reproducing the sound
field in frequency; characterized in that it comprises a sound field reproducing apparatus is
provided.
[0025]
According to this configuration, the amplification unit amplifies low-frequency audio information
that is information in a frequency domain below a predetermined frequency included in the
audio information to generate amplified low-frequency audio information, and the audio signal
generation unit generates the audio information Using the amplified low-frequency speech
information and the sound source position information, an m-channel sound signal for forming a
virtual sound source is generated by wave-field synthesis, the sound output unit wave-field
synthesizes the m-channel sound signal By outputting the sound, the sound field is reproduced in
the listening area including the assumed listener position.
As a result, by generating an audio signal in which the low frequency region is enhanced and
outputting the audio from the array speaker based on the audio signal, it is possible to reproduce
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the sound field by the virtual sound source in which the bass feeling is enhanced.
[0026]
In order to solve the above problems, according to another aspect of the present invention, audio
data including audio information and sound source position information is input, and from an
array speaker consisting of m speakers arranged in an array. A sound signal generation method
for generating a sound signal for reproducing a sound field consisting of a virtual sound source
arranged in a virtual space to a listening area including an assumed listener position of a real
space by outputting sound, Amplifying step of amplifying low frequency audio information which
is information of a frequency domain lower than a predetermined frequency and included in
audio information to generate amplified low frequency audio information; audio information,
amplified low frequency audio information and sound source position information An audio
signal generating step of generating an audio signal of m channels to form a virtual sound source
by wave field synthesis;
[0027]
According to this configuration, the amplification step amplifies low-frequency sound information
that is information in a frequency domain below a predetermined frequency included in the
sound information to generate amplified low-frequency sound information, and the sound signal
generation step The amplified low-frequency sound information and the sound source position
information are used to generate m channel sound signals for forming a virtual sound source by
wave-field synthesis.
As a result, it is possible to generate an audio signal for forming a virtual sound source by
wavefront synthesis in which the low frequency region is enhanced.
[0028]
In order to solve the above problems, according to another aspect of the present invention, audio
data including audio information and sound source position information is input, and from an
array speaker consisting of m speakers arranged in an array. A computer program for generating
an audio signal for reproducing a sound field consisting of a virtual sound source arranged in a
virtual space to a listening area including an assumed listener position of a real space by
outputting an audio: voice information And amplifying the low frequency audio information
which is information of a frequency region lower than a predetermined frequency and generating
amplified low frequency audio information; and using the audio information, the amplified low
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frequency audio information and the sound source position information Generating an audio
signal of m channels to form a virtual sound source by wavefront synthesis; generating an audio
signal; It is provided.
[0029]
According to this configuration, the amplification step amplifies low-frequency sound information
that is information in a frequency domain below a predetermined frequency included in the
sound information to generate amplified low-frequency sound information, and the sound signal
generation step The amplified low-frequency sound information and the sound source position
information are used to generate m channel sound signals for forming a virtual sound source by
wave-field synthesis.
As a result, it is possible to generate an audio signal for forming a virtual sound source by
wavefront synthesis in which the low frequency region is enhanced.
[0030]
As described above, according to the present invention, a new and improved sound field
reproduction device, an audio signal generation device, a sound field reproduction method, and a
sound field reproduction device capable of transmitting enhanced bass to the entire listening
area of a listener A computer program can be provided.
[0031]
The present invention will now be described more fully with reference to the accompanying
drawings, in which exemplary embodiments of the invention are shown.
In the present specification and the drawings, components having substantially the same
functional configuration will be assigned the same reference numerals and redundant description
will be omitted.
[0032]
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10
First Embodiment First, a sound field reproduction apparatus and an audio signal generation
apparatus according to a first embodiment of the present invention will be described. FIG. 1 is an
explanatory view for explaining the configuration of the sound field reproduction apparatus
according to the first embodiment of the present invention. The configuration of the sound field
reproduction apparatus according to the first embodiment of the present invention will be
described below using FIG.
[0033]
As shown in FIG. 1, the sound field reproduction device 10 according to the first embodiment of
the present invention includes an audio signal generation device 100 and m (m is an arbitrary
natural number) amplifiers 190a, 190b,. , 190 m, and m speakers 192 a, 192 b,..., 192 m.
[0034]
The audio signal generation apparatus 100 inputs audio data composed of n (n is an arbitrary
natural number) sound sources and outputs m (m is an arbitrary natural number) audio signals.
The m audio signals are for forming a virtual sound source by wave-field synthesis, and by
forming a virtual sound source, the listener is a sound with a sense of presence as if sound is
being emitted from that location. You can enjoy The audio data includes position information and
audio information of each virtual sound source, and the audio information can include
information such as the type and output level of each virtual sound source, and the duration of
sound.
[0035]
The amplifiers 190a, 190b,..., 190m amplify the audio signal generated by the audio signal
generation device 100. The speakers 192a, 192b,..., 192m are examples of the audio output unit
of the present invention, and the audio signals amplified by the amplifiers 190a, 190b,. Sound is
output by vibrating (not shown). Although the amplifier and the speaker are separately
configured in the present embodiment, a speaker with a built-in amplifier may be used. In that
case, the amplifier built-in speaker is the audio output unit of the present invention.
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[0036]
The configuration of the sound field reproduction apparatus according to the first embodiment of
the present invention has been described above. Next, the configuration of the audio signal
generation device 100 according to the first embodiment of the present invention will be
described.
[0037]
FIG. 2 is an explanatory diagram for explaining the configuration of the audio signal generation
device 100 according to the first embodiment of the present invention. The configuration of the
audio signal generation device 100 according to the first embodiment of the present invention
will be described below using FIG.
[0038]
As shown in FIG. 2, the audio signal generation device 100 according to the first embodiment of
the present invention includes low-frequency component separation units 110 a,..., 110 n, lowfrequency sound source position information calculation unit 120, and audio. A signal generation
unit 130, a low frequency sound signal generation unit 140, an amplification unit 142, and
mixers 150a, ..., 150m are included.
[0039]
The low frequency component separation units 110a,..., 110n receive the audio information of
each sound source input to the audio signal generation device 100, and separate the audio
signals of low frequency components having a predetermined frequency or less.
The low frequency component separation units 110a,..., 110n separate the sound signals from
the n sound sources into low frequency components and other components. For separation into
the low frequency component and the other components, for example, a band pass filter capable
of passing a desired frequency band may be used.
[0040]
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The reference frequency separated by the low frequency component separation units 110a, ...,
110n may be the lowest resonance frequency f0 of the speakers 192a, 192b, ..., 192m, or any
other frequency Good. Since the lowest resonance frequency f0 of the speakers 192a,..., 192 m is
generally about 150 Hz, it is preferable that the frequency to be separated by the low frequency
component separation units 110a,. .
[0041]
The low frequency sound source position information calculation unit 120 receives the sound
source position information of the sound source input to the sound signal generation device 100,
and calculates the position where the sound source of the low frequency component whose
frequency is lower than a predetermined frequency is arranged. The calculated arrangement
position information of the low frequency component sound source is sent to the low frequency
sound signal generation unit 140.
[0042]
The sound signal generation unit 130 forms a virtual sound source by synthesizing the
wavefronts of the sound output from the m speakers 192a, ..., 192m using the sound information
of the n sound sources and the sound source position information. To generate the audio signal
of m channels necessary for
[0043]
The low-frequency sound signal generation unit 140 generates sound source position
information based on the m sound sources calculated by the low-frequency sound source
position information calculation unit 120, and n of low-frequency components separated by the
low-frequency component separation units 110a,. The speech information of each sound source
is input, and m-channel sound signals for forming a virtual sound source are generated by
wavefront synthesis.
[0044]
The amplification unit 142 performs a process of amplifying a predetermined amount of n lowfrequency sound information generated by the low-frequency sound signal generation unit 140.
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Various amplification circuits may be used for amplification processing in the amplification unit
142.
The amount of amplification can be changed depending on the type of the speakers 192a,
192b,..., 192m, but it is desirable to amplify approximately 8 to 10 dB. By amplifying the low
frequency audio information by a predetermined amount, the bass feeling of the sound output
from the speakers 192a, 192b,. It can be reproduced.
[0045]
The mixers 150a,..., 150m respectively receive the m-channel audio signal output from the audio
signal generation unit 130 and the m-channel audio signal output from the amplification unit
142, and combine the two. An audio signal is output.
[0046]
The configuration of the audio signal generation device according to the first embodiment of the
present invention has been described above.
Next, an audio signal generation method according to the first embodiment of the present
invention will be described.
[0047]
Audio data of n sound sources is input to the sound field reproduction device 10. The voice data
includes, as described above, sound source position information which is information of the
arrangement location of the sound source in the virtual space, and voice information which is
information of a sound emitted from the sound source. The audio information includes
information such as the type of sound, the size of the sound, and the duration of the sound. The
sound field reproduction apparatus 10 generates an audio signal based on the information, and
the speakers 192a, 192b,..., Based on the generated audio information so as to obtain a uniform
wavefront in space by the wavefront synthesis technology. By outputting the sound from 192 m,
the listener can enjoy the sound as if the sound source is located at any place in the space.
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[0048]
The n sound source position information and the n sound information are input to the sound
signal generation device 100. The audio signal generation apparatus 100 into which the sound
source position information and the audio information are input generates an audio signal
internally, and m m are output to output audio from the m speakers 192a, 192b,. Output an
audio signal of
[0049]
The audio signal generation apparatus 100 outputs m audio signals based on the sound source
position information and audio information of n sound sources, but when outputting m audio
signals, the m audio signals are generated in a low frequency region lower than a predetermined
frequency. By amplifying the audio information and outputting the audio signal using the
amplified audio information, it is possible to give a bass feeling to the audio emitted from the
speakers 192a, 192b,. Methods of amplifying audio information in the low frequency region
include a method of amplifying the audio information as it is and a method of separating the
audio information and amplifying audio information of the separated low frequency region. In
the first embodiment of the present invention, a method of amplifying a low frequency region by
the latter will be described. In addition, when separating voice information, a method of
amplifying the voice of the low frequency region and outputting it as it is from the virtual sound
source, and newly placing the voice of the low frequency region as the low frequency sound
source There is a method of wave front synthesis including speech and outputting. In the first
embodiment of the present invention, a method of amplifying a low frequency region by the
latter will be described.
[0050]
The n pieces of audio information are input to the low frequency component separation units
110a,..., 110n. The input speech information is separated into low frequency components below
a predetermined frequency and the other components. The predetermined frequency may be the
lowest resonance frequency f0 of the speakers 192a, 192b,. In general, the minimum resonance
frequency f0 of a small speaker such as the speakers 192a, 192b,..., 192m constituting an array
speaker is about 150 Hz, so low frequency components and other components are separated at
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150 Hz. May be separated. Moreover, although the low frequency component separation unit is
provided for each sound source in the present embodiment, the present invention is not limited
to this, and only one low frequency component separation unit may be provided to perform
separation.
[0051]
In addition, the n sound source position information is input to an audio signal generation unit
130 which generates an audio signal, and a low frequency sound source position information
calculation unit 120 which calculates a position where the low frequency sound source is
arranged.
[0052]
The low frequency sound source position information calculation unit 120 calculates the position
at which the low frequency sound source is arranged.
The arrangement position of the low frequency sound source calculated by the low frequency
sound source position information calculation unit 120 may be fixed, or may be determined
according to the sound field to be reproduced. The arrangement position of the low frequency
sound source may be arranged, for example, on the center line of the array speaker, or may be
arranged near the sound source emitting the largest low frequency sound among the virtual
sound sources. For example, when the sound source reproduces a sound field consisting of three
types of violin, cello and contrabass, the low frequency sound source may be arranged near the
position of the contrabass. By arranging the low frequency sound source in the vicinity of the
sound source emitting the largest low frequency sound, the listener can obtain a more natural
bass feeling. The information on the arrangement position of the low frequency sound source
calculated by the low frequency sound source position information calculation unit 120 is input
to the low frequency sound signal generation unit 140.
[0053]
The audio information including components of a predetermined frequency or higher separated
by the low frequency component separation units 110a, ..., 110n is input to the audio signal
generation unit 130 together with n pieces of sound source position information, and is
estimated by wavefront synthesis. Generate m audio signals to form a sound source.
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[0054]
The low-frequency sound information separated by the low-frequency component separation
units 110 a,..., 110 n and including components of a predetermined frequency or less is the
arrangement of low-frequency sound sources calculated by the low-frequency sound source
position information calculation unit 120. The low frequency audio signal generator 140 is input
together with the position information.
The low frequency audio signal generation unit 140 generates low frequency audio signals
having m or less predetermined frequencies for forming a low frequency sound source by wavefield synthesis. Then, the m low frequency sound signals generated by the low frequency sound
signal generation unit 140 are amplified by the amplification unit 142.
[0055]
The m audio signals generated by the audio signal generation unit 130 and the m low frequency
audio signals generated by the low frequency audio signal generation unit 140 and amplified by
the amplification unit 142 are respectively mixer 150 a,. It is input to 150m. The mixers 150a, ...,
150m combine the m audio signals and the m low-frequency audio signals, and output sound by
wavefront synthesis from the m speakers 192a, 192b, ..., 192m. Output an audio signal of
[0056]
As described above, the audio signal generation device 100 outputs m audio signals based on
sound source position information and audio information of n sound sources.
[0057]
If the curvature radius of the wave front of the sound emitted from the virtual sound source on
the array speaker surface becomes large by the wave front synthesis, many speakers in the
speakers constituting the array speaker will output the sound.
By outputting the sound emitted from one virtual sound source from many speakers, the burden
on one speaker is reduced. Therefore, even if the audio output from the low frequency sound
09-05-2019
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source is electrically boosted by about 8 to 10 dB, the amplitude of the diaphragm of the speaker
can be kept within the possible amplitude range of the speaker.
[0058]
FIG. 3 is an explanatory view for explaining the arrangement position of the low frequency sound
source and the wave front of the sound emitted from the low frequency sound source according
to the first embodiment of the present invention. According to the example shown in FIG. 3, the
low frequency sound source is arranged on the center line of the array speaker so that the radius
of curvature on the array speaker surface is larger than the radius of curvature of the sound
wave front emitted from other virtual sources. There is. By positioning the low frequency sound
source on the center line of the array speaker, it is possible to reproduce the bass uniformly in
the space. By reproducing the bass uniformly in the space, the listener can obtain a natural bass
feeling.
[0059]
The arrangement position of the low frequency sound source for emitting the sound of the low
frequency component is not limited to the example shown in FIG. In FIG. 3, the low frequency
sound source position is arranged on the center line of the array speaker so that the radius of
curvature on the array speaker surface is larger than the radius of curvature of the wave front of
the sound emitted from other virtual sources. The low frequency sound source position may be
arranged in the vicinity of the sound source having the largest frequency component among the
n sound sources. By arranging the low-frequency sound source position near the sound source
having the largest frequency component among the n sound sources, the listener can obtain a
natural bass feeling. Even when the low frequency sound source is arranged so as to be in the
vicinity of the sound source having the largest frequency component, it is desirable to arrange so
that the radius of curvature on the array speaker surface becomes large. Further, when arranging
the low frequency sound source, it is desirable to arrange the low frequency sound source so as
to have a wavefront having a curvature radius larger than at least 1⁄4 of the total length of the
array speaker.
[0060]
FIG. 4 is an explanatory diagram for explaining changes in frequency characteristics before and
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after amplification in the low frequency region. As shown in FIG. 4, by amplifying only the low
frequency region, low-range sound can be reproduced without giving a load to the speaker even
with a relatively small diameter speaker constituting the array speaker. it can.
[0061]
The sound field reproducing method according to the first embodiment of the present invention
has been described above. In the present embodiment, the low frequency audio signal is
generated by the low frequency audio signal generation unit 140 and then amplification is
performed in the low frequency region by the amplification unit 142. After amplification in the
frequency domain, low frequency audio signals may be generated.
[0062]
As described above, according to the sound field reproduction device, the audio signal generation
device, and the audio signal generation method according to the first embodiment of the present
invention, the bass region is separated and amplified, and the sound is synthesized from the
array speaker by wavefront synthesis. By outputting, it is possible to reproduce a sound field in
which the feeling of bass is enhanced and interference does not occur.
[0063]
Second Embodiment In a second embodiment of the present invention, a sound field reproducing
apparatus and a sound field reproducing method will be described in which an audio signal
generation unit is provided for each sound source to generate an audio signal.
[0064]
FIG. 5 is an explanatory view for explaining a sound field reproduction apparatus according to
the second embodiment of the present invention.
The sound field reproduction apparatus according to the second embodiment of the present
invention will be described below with reference to FIG.
[0065]
09-05-2019
19
As shown in FIG. 5, the sound field reproduction device 20 according to the second embodiment
of the present invention includes n (n is an arbitrary natural number) audio signal generation
units 220 a,. m is any natural number) mixers 250a, 250b, ..., 250m, m amplifiers 290a, 290b, ...,
290m, m speakers 292a, 292b, ..., 292m, It is comprised including.
[0066]
The sound signal generation units 220a, ..., 220n respectively input sound source position
information and sound information of n sound sources in sound source units, and based on the
inputted sound source position information and sound information, a virtual sound source is
generated by wavefront synthesis. It generates m audio signals for reproducing audio.
The audio information includes information such as the type of sound, the size of the sound, and
the duration of the sound.
[0067]
The mixers 250a, 250b,..., 250m respectively receive the m audio signals generated by the audio
signal generators 220a,..., 220n, synthesize them, and output an audio signal.
[0068]
The amplifiers 290a, 290b,..., 290m respectively receive the audio signals output from the mixers
250a, 250b,..., 250m, and amplify and output the audio signals.
The speakers 292a, 292b,..., 292m are examples of the audio output unit of the present
invention, and constitute an array speaker, and are amplified and output from the amplifiers
290a, 290b,. The voice signals are respectively input, and a diaphragm (not shown) is vibrated
based on the input voice signals, and is output as voice.
Although the amplifier and the speaker are separately configured in this embodiment, a speaker
with a built-in amplifier may be used. In that case, the amplifier built-in speaker is the audio
output unit of the present invention.
09-05-2019
20
[0069]
The sound field reproduction apparatus according to the second embodiment of the present
invention has been described above. Next, an audio signal generation method according to the
second embodiment of the present invention will be described.
[0070]
Similar to the sound field reproduction apparatus 10 according to the first embodiment, sound
data of n sound sources is input to the sound field reproduction apparatus 20. The sound data
includes sound source position information which is information of the arrangement place of the
sound source in the virtual space, and sound information which is information of sound emitted
from the sound source. The audio information includes information such as the type of sound,
the size of the sound, and the duration of the sound. The sound field reproducing apparatus 20
generates an audio signal based on the information, and outputs the audio from the speakers
292a, 292b,..., 292m so as to obtain a uniform wavefront in space by a wavefront synthesis
technique. Thus, the listener can enjoy the sound as if the sound source is located anywhere in
the space.
[0071]
The n pieces of sound source position information and the n pieces of sound information are
respectively input to the sound signal generation units 220a, ..., 220n. The audio signal
generation units 220a, ..., 220n internally generate an audio signal, and output m audio signals to
output audio from m speakers 292a, 292b, ..., 292m. Output.
[0072]
Here, in order to enhance the bass of the sound output from the m speakers 292a, 292b,...,
292m, a low frequency equal to or less than a predetermined frequency is generated inside the
audio signal generation units 220a,. Perform processing to amplify the information of the area.
The process of amplifying may be performed before generating the audio signal or may be
performed after generating the audio signal. The amount of amplification can be changed
09-05-2019
21
according to the type of the speakers 292a, 292b,..., 292m, but it is desirable to amplify about 8
to 10 dB as in the first embodiment of the present invention. By amplifying the low frequency
audio information by a predetermined amount, the bass feeling of the sound output from the
speakers 292a, 292b,..., 292m can be enhanced, and the sound field reproducing apparatus 20
has a real feeling of enhanced bass feeling. A sound field can be reproduced.
[0073]
The m audio signals generated by the audio signal generators 220a, ..., 220n are input to the
mixers 250a, 250b, ..., 250m, respectively. The mixers 250a, 250b,..., 250m synthesize and
output the input audio signals. The audio signals output from the mixers 250a, 250b,..., 250m
pass through the amplifiers 290a, 290b,. A sound field consisting of a sound source is
reproduced.
[0074]
The audio signal generation method according to the second embodiment of the present
invention has been described above.
[0075]
As described above, according to the sound field reproduction apparatus and the sound signal
generation method of the second embodiment of the present invention, the bass region is
amplified, and sound is output from the array speaker by wavefront synthesis, so that a feeling of
bass is realized. The sound field can be reproduced without any interference.
[0076]
Third Embodiment In the second embodiment of the present invention, the low frequency region
is amplified inside the audio signal generation unit, but before the audio information is input to
the audio signal generation unit, the low frequency region is amplified. Amplification may be
performed.
[0077]
FIG. 6 is an explanatory diagram for explaining the configuration of the sound field reproduction
apparatus according to the third embodiment of the present invention.
09-05-2019
22
The configuration of the sound field reproduction apparatus according to the third embodiment
of the present invention will be described below using FIG.
[0078]
As shown in FIG. 6, the sound field reproduction device 30 according to the third embodiment of
the present invention includes n (n is an arbitrary natural number) amplification units 310 a,. ,
320 m, m (where m is an arbitrary natural number) mixers 350 a, 350 b,..., 350 m, m amplifiers
390 a, 390 b,. .., 392 m and each speaker 392 a, 392 b,.
[0079]
In the configuration of the sound field reproducing apparatus 30 shown in FIG. 6, mixers 350a,...,
350m, amplifiers 390a,..., 390m and speakers 392a,. , 250 m, amplifiers 290 a,..., 290 m and
speakers 292 a,..., 292 m of the sound field reproduction apparatus 20 according to the second
embodiment of the present invention.
Accordingly, here, amplification units 310a, ..., 310n and audio signal generation units 320a, ...,
320n having functions different from those of the sound field reproduction apparatus 20
according to the second embodiment of the present invention shown in Fig. 5. Will be explained.
[0080]
The amplification units 310a,..., 310n receive voice information of the sound sources 1,..., Sound
source n, respectively, and amplify and output voice information of a low frequency region lower
than a predetermined frequency.
The audio information in the low frequency region below the predetermined frequency that has
been output is input to the audio signal generation units 320a, ..., 320n.
[0081]
09-05-2019
23
The sound signal generating units 320a, ..., 320n receive sound source position information of n
sound sources and sound information of n sound sources passing through the amplifying units
310a, ..., 310n, and the sound source positions thus input Based on the information and voice
information, m voice signals for reproducing a virtual source voice by wavefront synthesis are
generated.
The audio information includes information such as the type of sound, the size of the sound, and
the duration of the sound.
[0082]
The configuration of the sound field reproduction apparatus according to the third embodiment
of the present invention has been described above. Next, an audio signal generation method
according to a third embodiment of the present invention will be described.
[0083]
Similar to the sound field reproduction apparatus 10 according to the first embodiment, the
sound field reproduction apparatus 30 receives audio data of n sound sources. The sound data
includes sound source position information which is information of the arrangement place of the
sound source in the virtual space, and sound information which is information of sound emitted
from the sound source. The audio information includes information such as the type of sound,
the size of the sound, and the duration of the sound. The sound field reproduction apparatus 20
generates an audio signal based on the information, and outputs audio from the speakers 392a,...,
392m so as to obtain a uniform wavefront in space by a wavefront synthesis technique. The
listener can enjoy the sound as if the sound source is located anywhere in space.
[0084]
The n pieces of sound source position information are input to the audio signal generation units
320a, ..., 320n. On the other hand, the n pieces of audio information are input to the
amplification units 310a,. The amplification units 310a,..., 310n amplify and output audio
information in a low frequency region equal to or lower than a predetermined frequency
09-05-2019
24
included in the n pieces of audio information. The amount of amplification can be changed
according to the type of the speakers 392a, ..., 392m, but it is desirable to amplify about 8 to 10
dB as in the first embodiment of the present invention. By amplifying the low frequency audio
information by a predetermined amount, the bass feeling of the sound output from the speakers
392a, ..., 392m can be enhanced, and the sound field reproduction device 30 reproduces a more
realistic sound field be able to.
[0085]
Audio signal generation units 320a,..., 320n to which n pieces of sound source position
information and n pieces of audio information obtained by amplifying low frequencies below a
predetermined frequency by the amplification units 310a,. , Generates an audio signal internally,
and outputs m audio signals in order to output audio from m speakers 392 a,..., 392 m.
[0086]
The m audio signals generated by the audio signal generators 320a, ..., 320n are input to the
mixers 350a, ..., 350m, respectively.
The mixers 350a,..., 350m synthesize and output the input audio signals. The sound signal output
from the mixer 350a,..., 350m passes through the amplifier 390a,..., 390m and the speakers
392a,. Is played.
[0087]
The audio signal generation method according to the third embodiment of the present invention
has been described above.
[0088]
As described above, according to the sound field reproduction apparatus and the sound signal
generation method of the third embodiment of the present invention, the bass region is
amplified, and sound is output from the array speaker by wavefront synthesis, so that a feeling of
bass is realized. The sound field can be reproduced without any interference.
[0089]
Fourth Embodiment In the fourth embodiment of the present invention, an audio signal
09-05-2019
25
calculated in advance so as to form a virtual sound source by wavefront synthesis is read, and a
sound field is generated by wavefront synthesis using the read audio signal. A sound field
reproducing apparatus and an audio signal generating method for reproducing
[0090]
FIG. 7 is an explanatory view for explaining a sound field reproduction apparatus according to
the fourth embodiment of the present invention.
The sound field reproduction apparatus according to the fourth embodiment of the present
invention will be described below with reference to FIG.
[0091]
As shown in FIG. 7, the sound field reproducing apparatus 40 according to the fourth
embodiment of the present invention includes an audio signal reading device 420 and m (m is an
arbitrary natural number) amplification units 410a, 410b,. , 410 m, m amplifiers 490 a, 490 b,...,
490 m, and m speakers 492 a, 492 b,.
[0092]
The audio signal reading device 420 reads an audio signal calculated in advance so as to form a
virtual sound source by wavefront synthesis.
The audio signal reader 420 includes a network transmitter / receiver 430, a digital broadcast
receiver 440, an optical disc reader 450, and a demultiplexer 460.
[0093]
The network transmission / reception device 430 receives an audio signal calculated in advance
so as to form a virtual sound source by wavefront synthesis from a network such as the Internet.
09-05-2019
26
The digital broadcast receiver 440 receives a digital broadcast signal.
It is assumed that the digital broadcast signal includes an audio signal calculated in advance to
form a virtual sound source by wavefront synthesis. The optical disk reader 450 reads an optical
disk. It is assumed that the optical disk read by the optical disk reader 450 contains an audio
signal calculated in advance so as to form a virtual sound source by wavefront synthesis.
[0094]
The demultiplexing unit 460 demultiplexes audio signals read by the network transmission /
reception device 430, the digital broadcast reception device 440, and the optical disk reader 450,
and extracts m audio signals. The m audio signals extracted by the demultiplexing are
respectively input to the amplifiers 410a,..., 410m.
[0095]
The amplification units 410a, 410b,..., 410m respectively receive the m audio signals
demultiplexed by the demultiplexing unit 460, and amplify the audio signals in the low frequency
region of a region below a predetermined frequency. Output. The audio signal in the low
frequency region amplified and output is input to the amplifiers 490a, 490b,.
[0096]
The amplifiers 490a, 490b,..., 490m respectively receive the m audio signals output from the
amplifiers 410a, 410b,. The speakers 492a, 492b,..., 492m constitute an array speaker, and the
amplified audio signals output from the amplifiers 490a, 490b,. The diaphragm (not shown) is
vibrated based on the signal and output as sound.
[0097]
The sound field reproduction apparatus according to the fourth embodiment of the present
invention has been described above. Next, the operation of the sound field reproduction
09-05-2019
27
apparatus according to the fourth embodiment of the present invention will be described.
[0098]
The sound field reproduction device 40 reads an audio signal calculated in advance so as to form
a virtual sound source by wavefront synthesis from a network, digital broadcast or an optical
disc, and based on the read audio signal, the speakers 492a, 492b,. , 492 m, the listener can
enjoy the sound as if the sound is emitted from the virtual sound source arranged in the space.
[0099]
When multiplexed voice signals are transmitted from a network such as the Internet, the network
transceiver 430 receives the multiplexed voice signals.
The received voice signal is sent to the demultiplexer 460 and demultiplexed to be m voice
signals.
[0100]
When the audio signal multiplexed by digital broadcasting has been transmitted, the audio signal
multiplexed by the digital broadcast receiver 440 is received. The received voice signal is sent to
the demultiplexer 460 and demultiplexed to be m voice signals.
[0101]
When the optical disk includes a multiplexed audio signal, the optical disk reader 450 reads the
multiplexed audio signal. The read audio signal is sent to the demultiplexer 460 and
demultiplexed to be m audio signals.
[0102]
The m audio signals demultiplexed by the demultiplexing unit 460 are input to the amplification
09-05-2019
28
units 410a, 410b,. The amount of amplification can be changed according to the type of the
speakers 492a, 492b,... 492m, but it is desirable to amplify about 8 to 10 dB as in the first to
third embodiments of the present invention. By amplifying the low frequency audio information
by a predetermined amount, the bass feeling of the sound output from the speakers 492a,
492b,... 492m can be enhanced, and the sound field reproduction device 40 can make the sound
field more realistic. It can be reproduced.
[0103]
The m audio signals output from the amplification units 410a, 410b, ..., 410m are input to the
amplifiers 490a, 490b, ..., 490m and amplified, and the m audio signals amplified are: By passing
the speakers 492a, 492b,..., 492m, sound is output, and a sound field composed of a virtual
sound source is reproduced in space.
[0104]
The operation of the sound field reproduction apparatus according to the fourth embodiment of
the present invention has been described above.
[0105]
Although the audio signal reading apparatus according to the present embodiment includes the
network transmitting / receiving apparatus, the digital broadcast receiving apparatus, and the
optical disc reading apparatus, the present invention is not limited to this, and the network
transmitting / receiving apparatus, digital broadcast receiving Any one or two of the device and
the optical disk reader may be included.
[0106]
As described above, according to the sound field reproducing apparatus according to the fourth
embodiment of the present invention, the low frequency region of the audio signal read from the
network, digital broadcast, optical disc or the like is amplified to enhance the bass feeling. Sound
field can be reproduced without interference.
[0107]
Fifth Embodiment In a fifth embodiment of the present invention, a sound field reproducing
apparatus for amplifying low frequency components after extracting low frequency component
audio information in advance and generating low frequency component audio signals explain.
09-05-2019
29
[0108]
FIG. 8 is an explanatory view for explaining a sound field reproduction apparatus according to a
fifth embodiment of the present invention.
The configuration of the sound field reproduction apparatus according to the fifth embodiment
of the present invention will be described below using FIG.
[0109]
As shown in FIG. 8, the sound field reproduction device 50 according to the fifth embodiment of
the present invention includes an audio signal reading device 520, low frequency audio signal
generation units 570, and m (m is an arbitrary natural number) Mixers 580a, 580b, ..., 580m, m
amplification units 510a, 510b, ..., 510m, m amplifiers 590a, 590b, ..., 590m, m speakers 592a,
592 b,..., 592 m.
[0110]
The audio signal reading device 520 is for reading an audio signal calculated in advance so that a
virtual sound source is formed by wavefront synthesis.
The audio signal reading device 520 includes a network transmission / reception device 530, a
digital broadcast receiving device 540, an optical disk reading device 550, and a demultiplexing
unit 560.
Among components of the audio signal reading device 520, the network transmission / reception
device 530, the digital broadcast receiving device 540, and the optical disk reading device 550
are components of the audio signal reading device 420 described in the fourth embodiment of
the present invention. Therefore, the detailed description is omitted here.
[0111]
The demultiplexing unit 560 demultiplexes audio signals read by the network transmission /
09-05-2019
30
reception device 530, the digital broadcast reception device 540, and the optical disk reading
device 550, and extracts m audio signals and low-frequency audio information of a
predetermined frequency or less. It is a thing.
The m audio signals extracted by the demultiplexing are input to the mixers 580a, 580b,...,
580m, and low frequency audio information lower than a predetermined frequency is input to
the low frequency audio signal generation unit 570.
[0112]
The low frequency audio signal generation unit 570 receives low frequency audio information of
a predetermined frequency or less extracted by the demultiplexer unit 560, and generates m low
frequency audio signals for forming a virtual sound source by wavefront synthesis. It is
The generated m low frequency sound signals are input to the mixers 580a, 580b,.
[0113]
The mixers 580a, 580b, ..., 580m combine the m audio signals extracted by the demultiplexing
unit 560 with the m low-frequency audio signals generated by the low-frequency audio signal
generation unit 570, and output the result. It is
The m audio signals output from the mixers 580a, 580b, ..., 580m are input to the amplification
units 510a, 510b, ..., 510m.
[0114]
Amplifiers 510a, 510b,..., 510m respectively receive the m audio signals synthesized by mixers
580a, 580b,..., 580m and amplify audio signals in a low frequency region lower than a
predetermined frequency. Output. The audio signals in the low frequency region below the
predetermined frequency amplified by the amplifiers 510a, 510b,..., 510m are input to the
amplifiers 590a, 590b,.
09-05-2019
31
[0115]
The amplifiers 590a, 590b,..., 590m respectively receive the m audio signals output from the
amplifiers 510a, 510b,..., 510m, and amplify and output the audio signals. The speakers 592a,
592b,..., 592m constitute an array speaker, and receive amplified voice signals output from the
amplifiers 590a, 590b,. The diaphragm (not shown) is vibrated based on the signal and output as
sound.
[0116]
The configuration of the sound field reproduction apparatus according to the fifth embodiment
of the present invention has been described above. Next, the operation of the sound field
reproduction apparatus according to the fifth embodiment of the present invention will be
described.
[0117]
The sound field reproduction device 50 reads an audio signal calculated in advance so as to form
a virtual sound source by wavefront synthesis from a network, digital broadcast or an optical
disk, and based on the read audio signal, the speakers 592a, 592, ... , Output sound from 592 m.
By this, the listener can enjoy the sound as if the sound is emitted from the virtual sound source
arranged in the space.
[0118]
When multiplexed voice signals are transmitted from a network such as the Internet, the network
transceiver 530 receives the multiplexed voice signals. The received speech signal is sent to the
demultiplexing unit 560, and demultiplexing is performed to form m speech signals.
[0119]
09-05-2019
32
When the audio signal multiplexed by digital broadcasting is transmitted, the digital broadcast
receiver 540 receives the multiplexed audio signal. The received speech signal is sent to the
demultiplexing unit 560, and demultiplexing is performed to form m speech signals.
[0120]
When the optical disk includes a multiplexed audio signal, the optical disk reader 550 reads the
multiplexed audio signal. The read voice signal is sent to the demultiplexing unit 560, and
demultiplexing is performed to form m voice signals.
[0121]
Here, in the present embodiment, the information read from the network, the digital broadcast or
the optical disc includes low-frequency audio information of a predetermined frequency or less in
advance. Therefore, if demultiplexing processing is performed by the demultiplexing unit 560,
low-frequency sound information having a predetermined frequency or less can be extracted in
addition to the m pieces of sound information.
[0122]
Low frequency audio information equal to or lower than the predetermined frequency extracted
by the demultiplexing unit 560 is input to the low frequency audio signal generation unit 570.
The low frequency audio signal generation unit 570 receives low frequency audio information,
generates an audio signal for forming a virtual sound source by wavefront synthesis, and outputs
the audio signal. In order to output sound from m speakers 592a, 592b,... 592m, m low
frequency sound signals are generated.
[0123]
The m low-frequency audio signals generated by the low-frequency audio signal generation unit
570 are input to the mixers 580a, 580b,..., 580m, together with the m audio signals extracted by
the demultiplexer unit 560. , The audio signal and the low frequency audio signal are
09-05-2019
33
synthesized. Then, the synthesized voice signal is input to the amplification units 510a, 510b,...,
510m, and a low frequency region below a predetermined frequency is amplified. The amount of
amplification can be changed according to the type of the speakers 592a, 592b,... 592m, but it is
desirable to amplify about 8 to 10 dB as in the first to fourth embodiments of the present
invention. By amplifying the low frequency audio information by a predetermined amount, the
bass feeling of the sound output from the speakers 592a, 592b,. It can be reproduced.
[0124]
The audio signals whose low frequency regions are amplified by the amplification units 510a,
510b, ..., 510m are amplified by the amplifiers 590a, 590b, ..., 590m, and are input to the
speakers 592a, 592b, ..., 592m. Thus, sound is output from the speakers 592a, 592b, ..., 592m. A
virtual sound source is formed in the space by the output of sound from the speakers 592a,
592b,..., 592m, and a sound field in which sound is output from the virtual sound source can be
reproduced.
[0125]
The operation of the sound field reproduction apparatus according to the fifth embodiment of
the present invention has been described above.
[0126]
Although the audio signal reading device according to the present embodiment also includes the
network transmitting / receiving device, the digital broadcast receiving device, and the optical
disk reading device, the present invention is not limited thereto, and the network transmitting /
receiving device, digital broadcast receiving Any one or two of the device and the optical disk
reader may be included.
Also in the present embodiment, as in the first embodiment of the present invention, audio
information in a frequency range lower than a predetermined frequency may be separately
formed as a low frequency virtual sound source.
[0127]
As described above, according to the sound field reproducing apparatus according to the fifth
09-05-2019
34
embodiment of the present invention, audio information in a low frequency region lower than a
predetermined frequency is prepared in advance and read from a network, digital broadcast,
optical disc, etc. By amplifying the audio information in the low frequency region, it is possible to
reproduce a sound field in which the feeling of bass is enhanced and interference does not occur.
[0128]
Sixth Embodiment In the fifth embodiment of the present invention, the sound field reproduction
apparatus has been described in which the low frequency region amplification is performed by
the amplification unit after the sound signal and the low frequency sound signal are synthesized
by the mixer. However, the present invention is not limited to this, and amplification in a low
frequency region may be performed before synthesis in a mixer.
In the sixth embodiment of the present invention, a sound field reproduction apparatus will be
described in which an amplification unit is provided before the mixing in the mixer to amplify the
low frequency region of the low frequency sound signal.
[0129]
FIG. 9 is an explanatory diagram for explaining a sound field reproduction apparatus according
to a sixth embodiment of the present invention. The configuration of the sound field reproduction
apparatus according to the sixth embodiment of the present invention will be described below
using FIG.
[0130]
As shown in FIG. 9, the sound field reproducing apparatus 60 according to the sixth embodiment
of the present invention includes an audio signal reader 620, a low frequency audio signal
generator 670, mixers 680a,. , Amplification units 610a, ..., 510m, amplifiers 690a, ..., 690m, and
speakers 692a, ..., 692m.
[0131]
09-05-2019
35
The audio signal reading device 620 is for reading an audio signal calculated in advance so as to
form a virtual sound source by wavefront synthesis.
The audio signal reader 620 includes a network transmitter / receiver 630, a digital broadcast
receiver 640, an optical disc reader 650, and a demultiplexer 660. The configuration of each part
of the audio signal reading device 520 is the same as each part of the audio signal reading device
520 described in the fifth embodiment of the present invention, so the detailed description is
omitted here.
[0132]
The demultiplexing unit 660 demultiplexes audio signals read by the network transmission /
reception device 630, the digital broadcast reception device 640, and the optical disk reading
device 650, and extracts m audio signals and low-frequency audio information of a
predetermined frequency or less. It is a thing. The m audio signals extracted by the
demultiplexing are input to the mixers 680 a, 680 b,..., 680 m, and low frequency audio
information below a predetermined frequency is input to the low frequency audio signal
generation unit 670.
[0133]
The low frequency audio signal generation unit 670 receives low frequency audio information of
a predetermined frequency or less extracted by the demultiplexing unit 660, and generates m
low frequency audio signals for forming a virtual sound source by wavefront synthesis. It is The
generated m low frequency speech signals are input to the amplification units 610a, 610b,...,
610m.
[0134]
The amplification units 610a, 610b,..., 610m respectively receive the m low-frequency audio
signals generated by the low-frequency audio signal generation unit 670, and amplify and output
low-frequency regions below a predetermined frequency. It is a thing. The amplified low
frequency audio signals are input to the mixers 680a, 680b,.
09-05-2019
36
[0135]
The mixers 680a, ..., 680m are m audio signals extracted by the demultiplexing unit 660 and the
low-frequency audio signal generation unit 670, and m amplified by the amplification units 610a,
..., 610m. It synthesizes and outputs this low frequency speech signal. The m audio signals output
from the mixers 680a, 680b, ..., 680m are input to the amplifiers 690a, 690b, ..., 690m.
[0136]
The amplifiers 690a, 690b,..., 690m respectively receive the m audio signals output from the
mixers 680a, 680b,..., 680m, and amplify and output the audio signals. The speakers 692a,
692b,..., 692m constitute an array speaker, and the amplified audio signals output from the
amplifiers 690a, 692b,. The diaphragm (not shown) is vibrated based on the signal and output as
sound.
[0137]
The configuration of the sound field reproduction apparatus according to the sixth embodiment
of the present invention has been described above. Next, the operation of the sound field
reproduction apparatus according to the sixth embodiment of the present invention will be
described.
[0138]
Similar to the sound field reproducing apparatus according to the fifth embodiment of the
present invention, the sound field reproducing apparatus 60 is an audio signal calculated in
advance such that a virtual sound source is formed by wave field synthesis from a network,
digital broadcast or an optical disc. , And outputs a sound from the speakers 692a,..., 692m based
on the read audio signal. By this, the listener can enjoy the sound as if the sound is emitted from
the virtual sound source arranged in the space.
[0139]
09-05-2019
37
When multiplexed voice signals are transmitted from a network such as the Internet, the network
transceiver 630 receives the multiplexed voice signals. The received speech signal is sent to the
demultiplexing unit 660, and demultiplexing is performed to form m speech signals.
[0140]
When the audio signal multiplexed by digital broadcasting has been transmitted, the audio signal
multiplexed by the digital broadcast receiver 640 is received. The received speech signal is sent
to the demultiplexing unit 660, and demultiplexing is performed to form m speech signals.
[0141]
When the optical disk includes a multiplexed audio signal, the optical disk reader 650 reads the
multiplexed audio signal. The read voice signal is sent to the demultiplexing unit 660, and
demultiplexing is performed to form m voice signals.
[0142]
Here, in the present embodiment, the information read from the network, the digital broadcast or
the optical disc includes low-frequency audio information of a predetermined frequency or less in
advance. Therefore, if demultiplexing processing is performed by the demultiplexing unit 660,
low-frequency sound information having a predetermined frequency or less can be extracted in
addition to the m pieces of sound information.
[0143]
Low frequency speech information equal to or lower than a predetermined frequency extracted
by the demultiplexing unit 660 is input to the low frequency speech signal generation unit 670.
The low frequency audio signal generation unit 670 inputs low frequency audio information,
generates and outputs an audio signal for forming a virtual sound source by wavefront synthesis.
The low frequency audio signal generation unit 670 generates m low frequency audio signals in
09-05-2019
38
order to output audio from the m speakers 692a, 692b,..., 692m.
[0144]
The m low frequency sound signals generated by the low frequency sound signal generation unit
670 are input to the amplification units 610a, 610b,..., 610m, and a low frequency region equal
to or lower than a predetermined frequency is amplified. The amount of amplification can be
changed depending on the type of the speakers 692a, 692b,... 692m, but it is desirable to amplify
about 8 to 10 dB as in the first to fourth embodiments of the present invention. By amplifying
the low frequency audio information by a predetermined amount, the bass feeling of the sound
output from the speakers 692a, 692b,... 692m can be enhanced, and the sound field
reproduction device 60 can make the sound field more realistic. It can be reproduced.
[0145]
The m low-frequency audio signals whose low-frequency regions are amplified are input to
mixers 680a, 680b,..., 680m, respectively, together with the m audio signals extracted by the
demultiplexing unit 660, A low frequency speech signal is synthesized. The synthesized audio
signals are amplified by the amplifiers 690a, 690b,..., 690m and input to the speakers 692a,
692b,. Is output. A virtual sound source is formed in the space by the output of sound from the
speakers 692a, 692b,..., 692m, and a sound field in which sound is output from the virtual sound
source can be reproduced.
[0146]
The operation of the sound field reproduction apparatus according to the sixth embodiment of
the present invention has been described above.
[0147]
In the present embodiment, after the m low-frequency sound signals are generated by the lowfrequency sound signal generation unit 670, low-frequency regions lower than a predetermined
frequency of each low-frequency sound signal are amplified by the amplification units 610a and
610b, Although amplification is performed at 610 m, the present invention is not limited to this,
and before the low frequency audio signal generation unit 670 generates m low frequency audio
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signals, an amplification unit is provided to set audio information The low frequency region
below the frequency of may be amplified.
Providing the amplification before the low frequency audio signal generation unit 670 generates
m low frequency audio signals has an effect of requiring only one amplification unit.
[0148]
Also, the audio signal reading apparatus according to the present embodiment also includes a
network transmitting / receiving apparatus, a digital broadcast receiving apparatus, and an
optical disc reading apparatus, but the present invention is not limited to this. Any one or two of
the device and the optical disk reader may be included. Also in the present embodiment, as in the
first embodiment of the present invention, audio information in a frequency range lower than a
predetermined frequency may be separately formed as a low frequency virtual sound source.
[0149]
The above-described audio signal generation method may be implemented by providing a storage
unit inside the sound field reproduction device or the audio signal generation device, and
sequentially calling out computer programs stored in the storage unit. As the storage unit,
various types of ROM (Read Only Memory) may be used.
[0150]
Although the preferred embodiments of the present invention have been described above with
reference to the accompanying drawings, it goes without saying that the present invention is not
limited to such examples. It will be apparent to those skilled in the art that various changes or
modifications can be conceived within the scope of the appended claims, and of course these also
fall within the technical scope of the present invention. It is understood.
[0151]
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40
It is an explanatory view explaining composition of a sound field reproduction device concerning
a 1st embodiment of the present invention. It is an explanatory view explaining composition of
an audio signal generation device concerning a 1st embodiment of the present invention. It is an
explanatory view explaining an arrangement position of a low frequency sound source
concerning a 1st embodiment of the present invention, and a wave front of a sound emitted from
a low frequency sound source. It is an explanatory view explaining change of frequency
characteristics before and behind amplification of a low frequency domain. It is an explanatory
view explaining a sound field reproduction device concerning a 2nd embodiment of the present
invention. It is an explanatory view explaining composition of a sound field reproduction device
concerning a 3rd embodiment of the present invention. It is an explanatory view explaining a
sound field reproduction device concerning a 4th embodiment of the present invention. It is an
explanatory view explaining a sound field reproduction device concerning a 5th embodiment of
the present invention. It is an explanatory view explaining a sound field reproduction device
concerning a 6th embodiment of the present invention. It is explanatory drawing which
represents the wave face from a sound source typically. It is an explanatory view explaining a
case where a wave front from two sound sources is reproduced by wave field synthesis. It is
explanatory drawing explaining the difference in the listening image by a stereo system and a
multi-channel audio system. It is an explanatory view explaining a frequency characteristic of a
general small caliber speaker.
Explanation of sign
[0152]
10, 20, 30, 40, 50, 60 Sound field reproduction device 100 Audio signal generation device 110a,
..., 110n Low frequency component separation unit 120 Low frequency sound source position
information calculation unit 130, 220a, ..., 220 m, 320a, ..., 320m, audio signal generation unit
140, 570, 670 low frequency audio signal generation unit 150a, ..., 150m, 250a, ..., 250m, 350a,
..., 350m, 580a, ... ... 580 m, 680 a, ..., 680 m Mixer 190 a, ..., 190 m, 290 a, ..., 290 m, 390 a, ...,
390 m, 490 a, ..., 490 m, 590 a, ... , 590 m, 690 a, ..., 690 m Amps 192 a, ..., 192 m, 292 a, ..., 292
m, 392 a, ..., 392 m, 492a, ..., 492 m, 592 a, ..., 592 m, 692 a, ..., 692 m Speakers 310a, ..., 310 n,
410 a, ..., 410 m, 510 a, ..., 510 m, 610a, ..., 610m amplification unit
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