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JP2013102389

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DESCRIPTION JP2013102389
Abstract: To make it possible to easily improve the sound quality of a set listening area. A division
unit (15) performs band division of an input sound signal. When the control unit 20 performs
sound output from the speakers 30-1 to 30-5 based on the input sound signal through the
plurality of speakers, the control unit 20 divides the high frequency signal component divided by
the dividing unit 15 into high By arranging multiple areas within the focal point where the signal
components below the range signal component are connected, the size of the area in focus can
be made uniform regardless of the frequency component, so an area where the high frequency
signal component decreases in the set listening area It is possible to prevent the occurrence of
the problem, and it is possible to easily improve the sound quality of the set listening area.
[Selected figure] Figure 6
Acoustic signal processing apparatus and acoustic signal processing method and program
[0001]
The present technology relates to an acoustic signal processing device, an acoustic signal
processing method, and a program.
[0002]
Conventionally, a method of controlling a viewing area using a plurality of speakers has been
proposed.
09-05-2019
1
For example, in Patent Document 1, a pair of speakers is disposed at an interval of 1/8
wavelength of the frequency component of the acoustic signal to 1 wavelength, and sound waves
output from both speakers in the listening space for both speakers Provide a filter that cancels
out by interference. Here, the area where the cancellation of the sound wave is achieved is
arbitrarily controlled according to the position of the sensor microphone by adjusting the filter
coefficient based on the detection output of the microphone provided in front of both the
speakers. .
[0003]
Further, in Japanese Patent Application Laid-Open No. 2008-101501, regarding the mid-bass
component of the acoustic signal, acoustic output is performed by mid-bass speakers juxtaposed
at an interval of 1?8 wavelength to 1 wavelength of the radiated sound wave. Also, with regard to
the high frequency range component, sound output is performed with the directional high
frequency sound array speaker. By performing sound output in this manner, it is performed to
make it difficult to listen to sounds according to the area, and to listen to sounds of different
contents.
[0004]
Furthermore, in Patent Document 3, an acoustic signal is applied to a plurality of acoustic output
elements through independent filters. Also, the filter is a filter coefficient in which the
observation signals at a plurality of control points arranged in the same space become desired
plane waves in the sound reproduction direction set in advance, and the observation signal
becomes zero in the sound cutoff region set in advance. I assume. By setting the filter coefficients
in this manner, it is performed to realize generation of a plane wave whose spread is suppressed.
[0005]
Patent No. 3422282 Patent No. 3422296 Patent No. 4027329
[0006]
By the way, when arranging a pair of speakers so that it may become an interval of 1/8
wavelength of a frequency component of an acoustic signal to 1 wavelength like patent
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document 1, the size of the crosstalk reduction area produced is a speaker interval It can not be
changed because it is fixed.
Further, since it is not intended to equalize the size of the crosstalk reduction area for each
frequency, there is a problem that, for example, the area becomes narrow in the high tone area.
[0007]
Further, in Patent Document 2, since high directivity loudspeakers and directivity control using a
speaker array are used in the high sound range, the settable listening area is limited, and the
number of arrays can be increased to increase the listening area, etc. It is necessary to take
action.
[0008]
Furthermore, in Patent Document 3, although a large number of control points are used to create
one listening area, the number of control points that can be generated in principle is one or more
less than the number of speakers in the array. A very large amount of speakers would be
required to create an area.
[0009]
Therefore, in this technology, it is an object of the present invention to provide an acoustic signal
processing device, an acoustic signal processing method, and a program that can easily improve
the sound quality of a set listening area.
[0010]
According to a first aspect of the present invention, there is provided a division unit that
performs band division of an input sound signal, and a high frequency signal component divided
by the division unit when sound output is performed based on the input sound signal through a
plurality of speakers According to another aspect of the present invention, there is provided an
acoustic signal processing apparatus including: a control unit in which a plurality of connection
points are arranged within a connection point of signal components below the high frequency
signal component divided by the division unit.
[0011]
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In this technique, band division of an input audio signal, for example, an audio signal of one or
more contents is performed.
When sound output is performed based on an input sound signal through a plurality of speakers,
control of the phase and gain of each signal component is performed using the distance from the
center of the plurality of speakers to the focal point where the signal components connect. A
plurality of focal points where frequency components higher than the frequency component set
in advance are connected are disposed within focal points where signal components below the
divided high-frequency signal component are connected.
Further, the wavelength of the frequency component set in advance is set based on, for example,
the size of the head of the listener.
[0012]
According to a second aspect of the present invention, there is provided a division unit that
performs band division of input sound signals of a plurality of contents, and the sound
generation unit performs sound output based on the input sound signals through a plurality of
speakers. According to another aspect of the present invention, there is provided an acoustic
signal processing apparatus including: a control unit in which a plurality of focal points of
divided high frequency band signal components are arranged within focal points of signal
components below the high frequency band signal component divided by the division unit.
[0013]
According to a third aspect of the present invention, there is provided a third aspect of the
present invention, which comprises the steps of performing band division of an input sound
signal, and connecting high frequency signal components divided by the division unit when
sound output is performed based on the input sound signal through a plurality of speakers. And
V. disposing a plurality of focal points within the focal point of signal components below the
high-frequency signal component divided by the division unit.
[0014]
A fourth aspect of this technology is a program that causes a computer to execute processing of
an input sound signal, and performs sound output based on the input sound signal through a
procedure for performing band division of the input sound signal and a plurality of speakers In
this case, the program causes the computer to execute a procedure of arranging a plurality of
focal points of the divided high frequency band signal components in a focal point of signal
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components below the divided high frequency band signal components.
[0015]
Note that the program of the present technology is, for example, a storage medium,
communication medium such as an optical disc, a magnetic disc, a semiconductor memory, etc.,
provided in a computer readable format to a general-purpose computer capable of executing
various program codes. It is a program that can be provided by a medium or a communication
medium such as a network.
By providing such a program in a computer readable form, processing according to the program
is realized on the computer.
[0016]
In this technique, when the input sound signal is divided into bands and sound output is
performed based on the input sound signal through a plurality of speakers, the connection point
of the divided high band signal components is the divided high band signal. A plurality of signal
components below the component are arranged in the connecting focal point.
For this reason, it becomes possible to arrange the in-focus area regardless of the frequency
component, and it is possible to easily improve the sound quality of the set listening area.
[0017]
It is a figure for demonstrating the principle of an acoustic signal processing apparatus.
It is a figure for demonstrating the listening area at the time of putting a control point in the
same position in all the frequency bands.
It is a figure for demonstrating the listening area | region at the time of providing multiple
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5
control points of a high-pass signal component in the listening area of the signal component
below a high-pass signal component.
It is the figure which showed typically the relationship between the frequency at the time of
providing multiple control points, and a focus size. It is a figure for demonstrating the position of
the control point in the case of equalizing the outer diameter of a listening area | region. It is the
figure which illustrated the composition of the sound signal processing device. It is a schematic
diagram of an operation of each part. It is a figure which shows the example of arrangement |
positioning of a speaker and a listening area. It is a figure for demonstrating the expansion of the
area diameter in a control point. It is a figure which shows the simulation result (1 kHz) of sound
pressure distribution. It is a figure which shows the simulation result (4 kHz) of sound pressure
distribution. It is a figure which shows the simulation result (8 kHz) of sound pressure
distribution. It is a flowchart which shows arrangement | positioning processing of the control
point provided in a listening area | region. It is the figure which illustrated the other structure
(The case where one listening area | region is produced | generated by one apparatus) of an
acoustic signal processing apparatus. It is the figure which illustrated the other structure (when
producing | generating several listening area | regions with one apparatus) of an acoustic signal
processing apparatus. It is the figure which illustrated the other structure (The case where
several listening area | regions are produced | generated by several apparatus) of an acoustic
signal processing apparatus.
[0018]
Hereinafter, modes for carrying out the present technology will be described. The description will
be made in the following order. ?? Principle of the present technology Configuration of sound
signal processing device 3. Operation of acoustic signal processor 4. 5. Other configuration of
acoustic system using acoustic signal processing device (when one listening area is generated by
one device) Another configuration of an acoustic system using an acoustic signal processing
device (when a plurality of listening areas are generated by one device) Another configuration of
an audio system using an audio signal processing apparatus (when a plurality of devices generate
a plurality of listening areas)
[0019]
??? Principle of the Present Technology> In the present technology, acoustic signals from one
or more signal sources are input to an acoustic signal processing apparatus. The acoustic signal
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processing device has a division unit and a control unit. The dividing unit divides the acoustic
signal into a plurality of frequency bands. The control unit adjusts the phase and amplitude of
the sound signal divided into the plurality of frequency bands, and when performing sound
output through the plurality of speakers, the connection point of the divided high band signal
component is the high band A plurality of signal components below the signal component are
arranged in the connecting focal point.
[0020]
The principle of the acoustic signal processing apparatus will be described below. The present
principle is based on multi-channel crosstalk cancellation, and the frequency component ???
included in the acoustic signal is considered. As shown in FIG. 1, the number of acoustic signals
input to the acoustic signal processing apparatus 10 is ?L?, the number of speakers connected
to the acoustic signal processing apparatus 10 to perform acoustic output is ?M?, and
distribution in space The number of control points to be set is "N". The number N of control
points is smaller than the number M of speakers (N <M).
[0021]
The acoustic signal input to the acoustic signal processing apparatus is ?s (?)? as shown in
equation (1). Further, the input signal of each speaker is ?x (?)? as shown in the equation (2).
Further, the acoustic signal observed at the control point is ?y (?)? as shown in equation (3).
In the equation, T indicates transposition.
[0022]
Here, the function from each speaker to each control point is an N О M matrix ?G (?)?, and a
filter for generating an acoustic signal to be output from the input acoustic signal to the speaker
is an M О L matrix ? It is set as W ((omega)). When the function is defined in this manner, the
relationship between the acoustic signal y (?) observed at the control point and the input signal
x (?) of the speaker is expressed by Equation (4). Further, the relationship between the input
signal x (?) of the speaker and the acoustic signal s (?) to be input is expressed by Equation (5).
09-05-2019
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[0023]
Furthermore, a function indicating the correspondence between the target sound and the input
sound, with "y '(?)" as the acoustic signal of the sound (hereinafter referred to as "target sound")
to be presented at each control point as shown in equation (6) Let ?A (?)? be an N О L matrix.
In this case, the relationship between the acoustic signal y '(. Omega.) Of the target sound and the
acoustic signal s (.omega.) To be input is expressed by equation (7).
[0024]
Here, in order to make the observation sound equal to the target sound, that is, y (?) = y ? (?),
equation (8) should be satisfied.
[0025]
As a method of obtaining the filter W (?) satisfying the equation (8), a method using a pseudo
inverse matrix as shown in the equation (9) can be considered.
In equation (9), G (?) <*> represents a conjugate transpose matrix of G (?).
[0026]
By applying the filter W (?) designed in this way, it becomes possible to listen to the target
sound at the control point. Further, when the filter W (?) is designed in this way, the obtained
listening area has a size proportional to the wavelength, and it becomes difficult to obtain a
sufficient size particularly in a high frequency area. Therefore, if the control point is slightly away
from the control point, the high frequency band decreases to cause a change in sound quality
and a sense of discomfort in hearing.
[0027]
For example, when control points are placed at the same position in all frequency bands, as
shown in FIG. 2 (A), a size covering the entire head can be secured as a listening area in the bass
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8
region due to differences in focal spot size depending on frequency. There is. On the other hand,
since the focal point size is small in the high tone range, there is a possibility that only the low
tone range may be heard in the listening range and only the high tone range may be heard in the
listening area. FIG. 2B schematically shows the relationship between the frequency and the size
of the focal point when there is one control point.
[0028]
Therefore, in the present technology, by changing the number and arrangement of control points
for each frequency band to compensate for the change in the size of the listening area that
differs depending on the frequency band, it is possible to change the sound quality and hearing
in the desired listening area. Reduce discomfort. Specifically, a plurality of focal points
connecting high-pass signal components are arranged in a focal point where signal components
below the high-pass signal component join, that is, control of high-pass signal components within
the focus of signal components below the high-pass signal component By providing a plurality of
points, changes in the focal point size of the high-pass signal component are compensated. For
example, when the low frequency band focal region is made to correspond to the listening
region, as shown in FIG. 3, providing three control points within the low frequency band focal
point increases the frequency and narrows the focal spot size. Also, it is possible to widen the
region where the high frequency signal component has high sound quality. Further, by changing
the position of the control point for each frequency, it is possible to make the area in which each
signal component has high sound quality the listening area.
[0029]
FIG. 4 schematically shows the relationship between the frequency and the focus size when a
plurality of control points are provided. The control point is increased if the focal spot size is
significantly smaller than the desired listening zone size. For example, when the focal spot size at
the frequency f1 is so small as to be negligible with respect to the size of the desired listening
area, the number of focal spots is three, that is, three control points at the frequency f1 or higher.
If the focal spot size at frequency f2 is so small as to be negligible with respect to the size of the
desired listening area, the number of focal spots is five, that is, five control points, at frequency
f2 or higher. The area can be expanded by increasing the control points in this manner.
Furthermore, even if the number of control points is the same in the same frequency band, the
outer diameters of the focal points in the entire control points can be made uniform by gradually
separating the positions of the control points as approaching the high frequency range. For
example, as shown in FIG. 5A, three control points are provided to set a listening area for the
09-05-2019
9
frequency fa. Here, when the positions of the three control points are fixed, the focal point size
becomes narrow if the frequency is the frequency fb higher than the frequency fa, so as shown in
(B) of FIG. Is the position Pb moved from the position Pa to the central portion. Therefore, as
shown in FIG. 5C, for example, by separating the positions of the other two control points with
reference to the position of the central control point, the outer diameter of the focal point is set
to the position Pa when the frequency is the frequency fa. Can be aligned with the listening area.
[0030]
??? Configuration of Sound Signal Processing Device> FIG. 6 illustrates the configuration of
the sound signal processing device. The acoustic signal processing device 10 includes a dividing
unit 15 and a control unit 20. In the acoustic signal processing apparatus shown in FIG. 6, each
of the three acoustic signals is divided into three frequency bands and signal processing such as
adjustment of phase and gain is performed, and five speakers are processed using the acoustic
signal after signal processing. From the case of performing sound output.
[0031]
The division unit 15 of the acoustic signal processing apparatus 10 shown in FIG. 6 is configured
using three band division filters 16-1 to 16-3. The control unit 20 includes addition units 22-1 to
22-5 for adding the signals after the phase / gain adjustment filters 21-high, 21-mid, 21-low and
the filter processing for adjusting the phase and gain of the acoustic signal. ing. Further, a
plurality of speakers 30-1 to 30-5 are connected to the acoustic signal processing apparatus 10.
Furthermore, a drive unit 35-1 that drives the speaker 30-1 based on the sound output signal
generated by the control unit 20, and a drive unit 35-2 to 35-5 that similarly drives the speakers
30-2 to 30-5. It is provided. The driving units 35-1 to 35-5 may be built in the acoustic signal
processing apparatus 10 or may be separately provided from the acoustic signal processing
apparatus 10.
[0032]
The band division filter 16-1 divides the input acoustic signal S1 into three frequency bands. The
band division filter 16-1 is configured such that the signal of the highest frequency band is the
phase / gain adjustment filter 21-high of the control unit 20, the signal of the next highest
frequency band is the phase / gain adjustment filter 21-mid, The signal is output to the phase /
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gain adjustment filter 21-low.
[0033]
The band division filter 16-2 divides the input acoustic signal S2 into three frequency bands. The
band division filter 16-2 includes the signal of the highest frequency band as the phase / gain
adjustment filter 21-high of the control unit 20, the signal of the next highest frequency band as
the phase / gain adjustment filter 21-mid, The signal is output to the phase / gain adjustment
filter 21-low.
[0034]
The band division filter 16-3 divides the input acoustic signal S3 into three frequency bands. The
band division filter 16-1 is configured such that the signal of the highest frequency band is the
phase / gain adjustment filter 21-high of the control unit 20, the signal of the next highest
frequency band is the phase / gain adjustment filter 21-mid, The signal is output to the phase /
gain adjustment filter 21-low.
[0035]
The phase / gain adjustment filter 21-high adjusts the phase and gain so that the target sound
can be obtained at the control point with respect to the signal of the highest frequency band
supplied from the band division filters 16-1 to 16-3. And generate an audio signal for each
speaker. The phase / gain adjustment filter 21-high outputs an acoustic signal generated for
acoustic output by the speaker 30-1 to the addition unit 22-1. Similarly, the phase / gain
adjustment filter 21-high outputs an acoustic signal generated to perform acoustic output by the
speakers 30-2 to 30-5 to the addition units 22-2 to 22-5.
[0036]
The phase / gain adjustment filter 21-mid has a phase or gain so that the target sound can be
obtained at the control point with respect to the signals of the second highest frequency band
supplied from the band division filters 16-1 to 16-3. Make adjustments and generate an acoustic
09-05-2019
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signal for each speaker. The phase / gain adjustment filter 21-mid outputs an acoustic signal
generated to perform acoustic output by the speaker 30-1 to the addition unit 22-1. Similarly,
the phase / gain adjustment filter 21-mid outputs an acoustic signal generated to perform
acoustic output by the speakers 30-2 to 30-5 to the addition units 22-2 to 22-5.
[0037]
The phase / gain adjustment filter 21-low adjusts the phase and gain so that the target sound can
be obtained at the control point with respect to the signal of the lowest frequency band supplied
from the band division filters 16-1 to 16-3. And generate an audio signal for each speaker. The
phase / gain adjustment filter 21-mid outputs an acoustic signal generated to perform acoustic
output by the speaker 30-1 to the addition unit 22-1. Similarly, the phase / gain adjustment filter
21-low outputs an acoustic signal generated to perform acoustic output by the speakers 30-2 to
30-5 to the addition units 22-2 to 22-5.
[0038]
The addition unit 22-1 adds the acoustic signals supplied from the phase / gain adjustment filters
21-higt, 21-mid, 21-low, and outputs the result to the drive unit 35-1. Similarly, the adding units
22-2 to 22-5 add the acoustic signals supplied from the phase / gain adjustment filters 21-higt,
21-mid, 21-low to the driving units 35-2 to 35-5. Output.
[0039]
The driving unit 35-1 converts the digital sound signal output from the adding unit 22-1 of the
sound signal processing device 10 into an analog sound signal. Further, the acoustic signal is
amplified by the gain set by the user or the gain set in advance and supplied to the speaker 30-1
to perform acoustic output. Similarly, the drive units 35-2 to 35-5 convert the digital sound
signal output from the addition units 22-2 to 22-5 of the sound signal processing apparatus 10
into an analog sound signal or amplify the signal. To the speakers 30-2 to 30-5 to perform sound
output.
[0040]
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??? Operation of Sound Signal Processing Device> The control unit 20 of the sound signal
processing device 10 performs filter processing so that the target sound can be heard at the
control point.
[0041]
As described above, for the design of the filter W (?) that makes it possible to listen to the target
sound at the control point, it is most convenient to use a pseudo-inverse matrix as in equation
(9). There is no need to use a matrix. Here, it is assumed that the environment to be used is ideal,
there is no reflection from the floor surface, walls, etc., and the transfer function between the
control point and the speaker can be described only by the phase delay due to the distance as
well as the attenuation due to the distance. At this time, the component of the n-th row and the
m-th column of the transfer function G (?), that is, the transfer function Gn, m (?) between the
n-th control point and the m-th speaker is between the sound speed c and the control point and
the speaker Can be expressed as equation (10) using the distance rn, m of and the imaginary unit
j.
[0042]
At this time, the conjugate transpose matrix G (?) <*> compensates for the phase delay due to
the distance from each speaker to each control point, and forms a focal point where the signals
from each speaker intensify at the control point. Act as an adaptive beamforming filter. The
remaining term (G (?) G (?) <*>) <-1> is another control of the directional beam signal emitted
toward each control point by G (?) <*> Acts as a crosstalk canceller to cancel out the leaked
component to the point.
[0043]
Therefore, the filter W (?) is calculated based on the equation (11) using the function B (?)
which is an M О N matrix.
[0044]
In addition, the schematic diagram of the effect | action of each site | part of Formula (11) is
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shown in FIG.
In order to consider the design method of the beam forming filter B (?), the sound pressure
distribution in the vicinity of the control point when B (?) = G (?) <*> is considered. Here, in the
example of the arrangement of the speakers and the listening area as shown in FIG. 8, it is
assumed that there is a control point at a distance r from the center of the array speaker. At this
time, when the distance r is sufficiently larger than the diameter of the speaker array, the sound
pressure distribution around the control point is a space based on the principle of Fraunhofer
diffraction and the sound pressure distribution on the surface including the control points It is
known that the relationship is as follows. Therefore, the area diameter at the control point is
enlarged by suppressing the spatial high frequency component of the control point surface by
processing such as weakening the speaker outside the array and strengthening the inner speaker.
For example, as shown in FIG. 9, when processing is performed to weaken the speakers outside
the array and strengthen the speakers inside, the sound pressure distribution around the control
point is broken lines (when processing is not performed) to solid lines (processing And the region
where the sound pressure level is high can be broadened. When processing is performed to
weaken the speakers outside the array and strengthen the inside speakers, B (?) is set using a
diagonal matrix D in which diagonal components are set to weaken the outside speakers and
strengthen the inside speakers. The filter design may be performed as:) = DG (?) <*>. By
applying this processing as high frequency as high frequency and low frequency as low
frequency, it is possible to reduce the difference in area diameter for each frequency.
[0045]
If a matrix A (?) indicating a correspondence relationship is set in, for example, equation (12), it
becomes a condition that sounds of the same strength are simultaneously presented at two
control points existing at different positions in s1 (?). . Similarly, at two control points existing at
different positions even in s2 (?), it is a condition that sounds of the same strength are
simultaneously presented. Under such conditions, the solution of W (?) tends to be unstable
when the number of control points is increased. Therefore, such an influence can be reduced by
setting the following component of the matrix A (?) using the distance (rn) from the center of
the array to the control point using the equation (13).
[0046]
For obtaining the transfer function G (?), in addition to using the ideal transfer function
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assuming that it is shown in the above equation (10), it is also possible to measure and use the
transfer function using a direct microphone Conceivable. As the microphone used at that time, it
is conceivable to use an omnidirectional microphone. However, in cases where a precise transfer
function is required, the difference between the transfer function when the microphone is in
place and the transfer function when the human body is there, or due to the human head transfer
function. The impact must also be taken into account. Therefore, separation performance can be
improved by acquiring a transfer function that takes into account the effect by measuring with a
dummy head or superimposing a head-related transfer function by direction on the transfer
function measured by a microphone become.
[0047]
In addition, the intervals of the speakers constituting the speaker array do not necessarily have
to be constant. As shown in Japanese Patent Application Publication No. 9-512159, the speaker
spacing is arranged to follow a logarithmic distribution, and the speaker spacing is made uneven,
thereby reducing the side lobes of the directional characteristics produced by the filter B (?). It
is possible.
[0048]
Here, in the arrangement example shown in FIG. 8, simulation results of sound pressure
distribution in the case where control points are provided in the listening area are illustrated in
FIGS. 10 to 12. In addition, the distance in FIG. 8 makes a unit "mm". Also, in FIGS. 10 to 12, a
listening area Ua indicated by a black dotted line is an area set to allow sound to be heard, and a
listening area Ub indicated by a white dotted line is an area set to prevent sound from being
heard. There is.
[0049]
FIG. 10 illustrates the distribution of sound pressure levels when one control point is provided at
the center of the listening area for a 1 kHz signal component. In the listening area Ua, a change
in sound pressure level is small and a high sound pressure level is obtained. In the listening area
Ub, the change in sound pressure level is small and the sound pressure level is low. That is, it is
possible to control so that the sound of the 1 kHz signal component can be heard in the listening
area Ua and the sound of the 1 kHz signal component can not be heard in the listening area Ub.
09-05-2019
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[0050]
FIG. 11 illustrates the distribution of sound pressure levels for signal components of 4 kHz. 11A
shows a case where one control point is provided at the center of the listening area, and FIG. 11B
shows a case where control points are provided on both sides of the control point at the center of
the listening area. There is. As shown in FIG. 11A, when there is one control point, a change in
sound pressure level occurs in the listening area Ua, resulting in an area with a low sound
pressure level. Similarly, a change in sound pressure level occurs in the listening area Ub,
resulting in an area with a high sound pressure level. That is, an area where the sound of the 4
kHz signal component is difficult to hear in the listening area Ua and an area where the sound of
the 4 kHz signal component is audible in the listening area Ub are generated.
[0051]
Here, as shown in FIG. 11B, when there are three control points, a change in the sound pressure
level is small and a high sound pressure level is obtained in the listening area Ua. Similarly, in the
listening area Ub, a change in sound pressure level is small and a low sound pressure level can be
obtained. That is, it is possible to control so that the sound of the 4 kHz signal component can be
heard in the listening area Ua and the sound of the 4 kHz signal component can not be heard in
the listening area Ub.
[0052]
FIG. 12 illustrates the distribution of sound pressure levels for 8 kHz signal components. 12A
shows the case where one control point is provided at the center of the listening area, and FIG.
12B shows the case where control points are provided on both sides of the control point at the
center of the listening area. (C) shows the case where control points are further provided on both
sides. As shown in FIG. 12A, when there is one control point, a change in sound pressure level
occurs in the listening area Ua, resulting in an area with a low sound pressure level. Similarly, a
change in sound pressure level occurs in the listening area Ub, resulting in an area with a high
sound pressure level. That is, an area where it is difficult to hear the sound of the 8 kHz signal
component in the listening area Ua and an area where the sound of the 8 kHz signal component
is heard in the listening area Ub are generated.
09-05-2019
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[0053]
Also, as shown in FIG. 12B, when there are three control points, the sound pressure level is
smaller in the listening area Ua than in the case where there are one control point, but the sound
pressure level is small. An area of decreasing Similarly, in the listening area Ub, there are few
areas where the sound pressure level is high compared to the case where one control point is
present, but areas where the sound pressure level is high are generated. That is, it is possible to
reduce an area where it is difficult to hear the sound of the 8 kHz signal component in the
listening area Ua and an area where the sound of the 8 kHz signal component is heard in the
listening area Ub. However, it is impossible to eliminate the area where it is difficult to hear the
sound of the 8 kHz signal component in the listening area Ua, and the area where the sound of
the 8 kHz signal component is heard in the listening area Ub.
[0054]
Here, as shown in FIG. 12C, when there are five control points, a change in sound pressure level
is small within the listening area Ua, and a high sound pressure level can be obtained. Similarly,
in the listening area Ub, a change in sound pressure level is small and a low sound pressure level
can be obtained. That is, it is possible to control so that the sound of the 8 kHz signal component
can be heard in the listening area Ua and the sound of the 8 kHz signal component can not be
heard in the listening area Ub.
[0055]
As described above, by increasing the control point for the high frequency signal, the listening
area for the high frequency signal can be expanded. Therefore, it is possible to suppress variation
in the size of the generated listening area for each frequency band and to generate a desired
listening area in a wider frequency band, so that high sound quality of the presented audio signal
is realized. In addition, by expanding the listening area, it is possible to realize the convenience
that a sufficient effect can be obtained even if the listener moves from a position where he or she
listens to some extent.
[0056]
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17
The process of arranging the control points provided in the listening area may be the process
shown in the flowchart shown in FIG. Further, in changing the control point, a plurality of
frequency components higher than the frequency components set in advance are arranged
within the focal point where signal components below the high frequency signal component are
connected. For example, if the size of the listening area is determined on the basis of the size of
the human head, whether the number of control points for each listening area should be 1 or
more at a value around 1 kHz frequency where the wavelength is about 34 cm Decide.
[0057]
The frequency band that can be presented by the present technology is limited by the conditions
of the speaker array, the positional relationship of the listening area, and the like. For example,
the upper limit frequency is determined by the maximum number of control points (ie, the
number of speakers in the array) and the size of the listening area. It is preferable to limit
reproduction by a low-pass filter or the like for frequency components whose range that can be
covered by the control point becomes unignorably small compared to the listening region.
Further, the lower limit frequency is determined by the distance between the listening areas. For
example, in the case where three listening areas are arranged with a center-to-center distance of
1 m, and different sounds are presented for each, separation is difficult in principle for frequency
components whose wavelength greatly exceeds 1 m. As a result, the filter becomes unstable such
that the inverse matrix (G (?) B (?)) <-1> does not exist. Therefore, it is preferable to limit
reproduction by a high pass filter or the like.
[0058]
In step ST1, the acoustic signal processing device 10 performs initial setting. The acoustic signal
processing apparatus 10 sets, for example, the frequency component ??? to the lower limit
frequency ??L? as an initial value of the filter design. Also, the number "N" of control points is
set to the number "Ns" of target listening areas, and the process proceeds to step ST2.
[0059]
In step ST2, the acoustic signal processing device 10 evenly arranges N control points in the
target listening area. The acoustic signal processing apparatus 10 is disposed at the center in the
09-05-2019
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target listening area, for example, when there is one control point. In addition, when there are
three control points, the inside of the target listening area is equally divided into three, the
control points are arranged at the centers of the respective areas, and the process proceeds to
step ST3.
[0060]
The acoustic signal processing device 10 obtains the filter W in step ST3. The acoustic signal
processing device 10 calculates the filter W (?) based on the equation (11), and proceeds to step
ST4.
[0061]
In step ST4, the acoustic signal processing device 10 performs a simulation. The acoustic signal
processing apparatus 10 performs numerical simulation of the sound pressure level in the
listening area when the acoustic output is performed by the filter W (?) calculated in step ST3,
and proceeds to step ST5.
[0062]
In step ST5, the acoustic signal processing device 10 determines whether the target listening
area is satisfied more than a predetermined amount. The acoustic signal processing apparatus 10
determines how much the acceptable sound pressure level range is in the target listening area,
and if it is less than or equal to the predetermined ratio, the process proceeds to step ST6. To
step ST8.
[0063]
In step ST6, the acoustic signal processing apparatus 10 determines whether the number N of
control points is smaller than the value "M-1" obtained by subtracting 1 from the number "M" of
speakers. The acoustic signal processing device 10 proceeds to step ST7 when the condition of
?N <M?1? is satisfied, and proceeds to step ST11 when the condition is not satisfied.
09-05-2019
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[0064]
In step ST7, the acoustic signal processing device 10 increments the number N of control points
by one and returns to step ST2.
[0065]
In step ST8, the acoustic signal processing apparatus 10 determines whether the generated area
is too large for the target listening area.
The sound signal processing apparatus 10 compares the size of the target listening area with the
listening area generated when the number of control points in the frequency component ???
is ?N?. The acoustic signal processing device 10 proceeds to step ST9 when the generated
listening area is larger than the target listening area, for example, when the generated listening
area is larger than the target listening area and exceeds the predetermined ratio. Further, when
the generated listening area is not too large, the acoustic signal processing device 10 proceeds to
step ST11.
[0066]
In step ST9, the acoustic signal processing apparatus 10 determines whether the number "N" of
control points is larger than the number "Ns" of target listening areas. When the number "N" of
control points is larger than the number "Ns" of target listening areas, the acoustic signal
processing device 10 proceeds to step ST10, and proceeds to step ST11 when the number is not
larger.
[0067]
In step ST10, the acoustic signal processing device 10 arranges the control points at narrow
intervals. In the acoustic signal processing apparatus 10, the listening area generated when the
number of control points is ?N? is wide, and the number of control points is larger than the
number of listening areas, so the generated listening area is narrowed. The interval between
control points is narrowed and the process returns to step ST3.
09-05-2019
20
[0068]
In step ST11, the acoustic signal processing apparatus 10 determines whether the frequency
component "?" exceeds the upper limit frequency "?H". The acoustic signal processing device
10 proceeds to step ST12 when the frequency component "?" does not exceed the upper limit
frequency "?H", and ends the process when the frequency component "?" exceeds the upper
limit frequency "?H".
[0069]
In step ST12, the acoustic signal processing device 10 updates the frequency component "?".
The sound signal processing apparatus 10 can determine the number and arrangement of
control points at which the target listening area can be generated for the frequency component
??? by performing the processes of step ST2 to step ST9. Therefore, the frequency component
"?" is changed to a frequency higher by a predetermined frequency, and the process returns to
step ST2 to determine the number and arrangement of control points that can generate the
target listening area for the new frequency component.
[0070]
When such processing is performed, for example, as shown in FIG. 11A, the ratio of the area
where the sound pressure level is not lowered in the listening area Ua or the area where the
sound pressure level is not high in the listening area Ub is If the ratio is equal to or less than the
predetermined ratio, the number of control points can be increased to generate a target listening
area as shown in FIG. Further, when the processing for the frequency in FIG. 11 is completed, the
processing for the frequency shown in FIG. 12 is subsequently performed, and a target listening
area can be generated as shown in FIG.
[0071]
??? Another Configuration of Acoustic System Using Acoustic Signal Processing Device (When
Presenting Single Content to a Single Listening Area Created by a Single Acoustic Signal
Processing Device)> FIG. 14 shows an acoustic signal processing device As another configuration
09-05-2019
21
of the sound system using the above, the case where one piece of equipment presents single
content to one listening area is illustrated. The acoustic signal processing apparatus 10 is
configured to use one band division filter 16 because one acoustic signal is input. The control
unit 20 adds the signals after filter processing to the phase / gain adjustment filters 21-high, 21mid, 21-low that adjust the phase and gain of the acoustic signal as described above. It has -5.
Further, a plurality of speakers 30-1 to 30-5 are connected to the acoustic signal processing
apparatus 10. Furthermore, a drive unit 35-1 that drives the speaker 30-5 based on the sound
output signal generated by the control unit 20, and a drive unit 35-2 to 35-5 that similarly drives
the speakers 30-2 to 30-5. It is provided.
[0072]
The band division filter 16 divides the input acoustic signal S1 into three frequency bands. The
band division filter 16 uses the signal of the highest frequency band as the phase / gain
adjustment filter 21-high of the control unit 20, the signal of the next highest frequency band as
the phase / gain adjustment filter 21-mid, and the signal of the lowest frequency band. Output to
the phase / gain adjustment filter 21-low.
[0073]
The phase / gain adjustment filter 21-high adjusts the phase and gain of the signal of the highest
frequency band supplied from the band division filter 16 so that the target sound can be
obtained at the control point, and the sound of each speaker Generate a signal. The phase / gain
adjustment filter 21-high outputs an acoustic signal generated for acoustic output by the speaker
30-1 to the addition unit 22-1. Similarly, the phase / gain adjustment filter 21-high outputs an
acoustic signal generated to perform acoustic output by the speakers 30-2 to 30-5 to the
addition units 22-2 to 22-5.
[0074]
The phase / gain adjustment filter 21-mid adjusts the phase and gain of the signal of the second
highest frequency band supplied from the band division filter 16 so that the target sound can be
obtained at the control point. Generates an acoustic signal of The phase / gain adjustment filter
21-mid outputs an acoustic signal generated to perform acoustic output by the speaker 30-1 to
the addition unit 22-1. Similarly, the phase / gain adjustment filter 21-mid outputs an acoustic
09-05-2019
22
signal generated to perform acoustic output by the speakers 30-2 to 30-5 to the addition units
22-2 to 22-5.
[0075]
The phase / gain adjustment filter 21-low adjusts the phase and gain of the lowest frequency
band signal supplied from the band division filter 16 so that the target sound can be obtained at
the control point, and the sound of each speaker Generate a signal. The phase / gain adjustment
filter 21-mid outputs an acoustic signal generated to perform acoustic output by the speaker 301 to the addition unit 22-1. Similarly, the phase / gain adjustment filter 21-low outputs an
acoustic signal generated to perform acoustic output by the speakers 30-2 to 30-5 to the
addition units 22-2 to 22-5.
[0076]
The addition unit 22-1 adds the acoustic signals supplied from the phase / gain adjustment filters
21-higt, 21-mid, 21-low, and outputs the result to the drive unit 35-1. Similarly, the adding units
22-2 to 22-5 add the acoustic signals supplied from the phase / gain adjustment filters 21-higt,
21-mid, 21-low to the driving units 35-2 to 35-5. Output.
[0077]
The driving unit 35-1 converts the digital sound signal output from the adding unit 22-1 of the
sound signal processing device 10 into an analog sound signal. Further, the acoustic signal is
amplified by the gain set by the user or the gain set in advance and supplied to the speaker 30-1
to perform acoustic output. Similarly, the drive units 35-2 to 35-5 convert the digital sound
signal output from the addition units 22-2 to 22-5 of the sound signal processing apparatus 10
into an analog sound signal or amplify the signal. To the speakers 30-2 to 30-5 to perform sound
output.
[0078]
By controlling the number and arrangement of control points for each frequency band, the
acoustic signal processing apparatus 10 configured in this way can listen to high-quality sound
only in one listening area.
09-05-2019
23
[0079]
???
Another Configuration of Acoustic System Using Acoustic Signal Processing Device (When
Presenting Multiple Content to Multiple Listening Areas Created by a Single Acoustic Signal
Processing Device)> FIG. 15 shows an audio signal processing device As another configuration of
the audio system, the case where different contents are presented in, for example, two listening
areas by one audio signal processing apparatus is illustrated. The division unit 15 of the acoustic
signal processing apparatus 10 is configured using two band division filters 16-1 and 16-2. The
control unit 20 includes addition units 22-1 to 22-5 for adding the signals after the phase / gain
adjustment filters 21-high, 21-mid, 21-low and the filter processing for adjusting the phase and
gain of the acoustic signal. ing. Further, a plurality of speakers 30-1 to 30-5 are connected to the
acoustic signal processing apparatus 10. Furthermore, a drive unit 35-1 that drives the speaker
30-1 based on the sound output signal generated by the control unit 20, and a drive unit 35-2 to
35-5 that similarly drives the speakers 30-2 to 30-5. It is provided.
[0080]
The band division filter 16-1 divides the input acoustic signal S1 into three frequency bands. The
band division filter 16-1 is configured such that the signal of the highest frequency band is the
phase / gain adjustment filter 21-high of the control unit 20, the signal of the next highest
frequency band is the phase / gain adjustment filter 21-mid, The signal is output to the phase /
gain adjustment filter 21-low.
[0081]
The band division filter 16-2 divides the input acoustic signal S2 into three frequency bands. The
band division filter 16-2 includes the signal of the highest frequency band as the phase / gain
adjustment filter 21-high of the control unit 20, the signal of the next highest frequency band as
the phase / gain adjustment filter 21-mid, The signal is output to the phase / gain adjustment
filter 21-low.
09-05-2019
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[0082]
The phase / gain adjustment filter 21-high adjusts the phase and gain so that the target sound
can be obtained at the control point with respect to the signal of the highest frequency band
supplied from the band division filters 16-1 and 16-2. And generate an audio signal for each
speaker. The phase / gain adjustment filter 21-high outputs an acoustic signal generated for
acoustic output by the speaker 30-1 to the addition unit 22-1. Similarly, the phase / gain
adjustment filter 21-high outputs an acoustic signal generated to perform acoustic output by the
speakers 30-2 to 30-5 to the addition units 22-2 to 22-5.
[0083]
The phase / gain adjustment filter 21-mid has the phase and gain so that the target sound can be
obtained at the control point with respect to the signal of the second highest frequency band
supplied from the band division filters 16-1 and 16-2. Make adjustments and generate an
acoustic signal for each speaker. The phase / gain adjustment filter 21-mid outputs an acoustic
signal generated to perform acoustic output by the speaker 30-1 to the addition unit 22-1.
Similarly, the phase / gain adjustment filter 21-mid outputs an acoustic signal generated to
perform acoustic output by the speakers 30-2 to 30-5 to the addition units 22-2 to 22-5.
[0084]
The phase / gain adjustment filter 21-low adjusts the phase and gain so that the target sound can
be obtained at the control point with respect to the signal of the lowest frequency band supplied
from the band division filters 16-1 and 16-2. And generate an audio signal for each speaker. The
phase / gain adjustment filter 21-mid outputs an acoustic signal generated to perform acoustic
output by the speaker 30-1 to the addition unit 22-1. Similarly, the phase / gain adjustment filter
21-low outputs an acoustic signal generated to perform acoustic output by the speakers 30-2 to
30-5 to the addition units 22-2 to 22-5.
[0085]
The addition unit 22-1 adds the acoustic signals supplied from the phase / gain adjustment filters
09-05-2019
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21-higt, 21-mid, 21-low, and outputs the result to the drive unit 35-1. Similarly, the adding units
22-2 to 22-5 add the acoustic signals supplied from the phase / gain adjustment filters 21-higt,
21-mid, 21-low to the driving units 35-2 to 35-5. Output.
[0086]
The driving unit 35-1 converts the digital sound signal output from the adding unit 22-1 of the
sound signal processing device 10 into an analog sound signal. Further, the acoustic signal is
amplified by the gain set by the user or the gain set in advance and supplied to the speaker 30-1
to perform acoustic output. Similarly, the drive units 35-2 to 35-5 convert the digital sound
signal output from the addition units 22-2 to 22-5 of the sound signal processing apparatus 10
into an analog sound signal or amplify the signal. To the speakers 30-2 to 30-5 to perform sound
output.
[0087]
The sound signal processing apparatus 10 configured as described above can listen to highquality sound of different contents in two listening areas by controlling the number and
arrangement of control points for each frequency band. Therefore, for example, stereo
reproduction by presenting separate sounds to the right ear and the left ear of one person can be
realized with high sound quality. In addition, when playing back content such as a movie, the
video can be displayed as a single screen, and the voice of the original language can be presented
in the first listening area, and the dubbed voice can be presented with high sound quality in the
second listening area. become. In addition, it is possible to present the voice of a movie in the
first listening area and the voice of another content such as an explanation of the movie in high
quality in the second listening area. That is, it is possible to separate the content to be presented
according to the place where the sound is presented and the listener.
[0088]
??? Another Configuration of Acoustic System Using Acoustic Signal Processing Device (When
Reproducing Multiple Contents by Plural Acoustic Signal Processing Devices)> FIG. 16 shows two
acoustic systems as another configuration of the acoustic system using the acoustic signal
processing device. For example, the case of presenting different content in two listening areas
using an audio signal processing device is illustrated.
09-05-2019
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[0089]
The first acoustic signal processing device 10a and the second acoustic signal processing device
10b are configured in the same manner as the acoustic signal processing device 10 shown in FIG.
15, respectively. The first acoustic signal processing device 10a and the second acoustic signal
processing device 10b set a first listening area and a second listening area for the acoustic
signals S1 and S2, respectively.
[0090]
The audio signal processing devices 10a and 10b configured in this way can listen to high-quality
sound of different contents in two listening areas by controlling the number and arrangement of
control points for each frequency band. . Therefore, it is possible to separate and present, for
each content, a plurality of pieces of content to be presented according to the place where the
sound is presented and the listener. For example, in the case where a plurality of pictures are
displayed side by side in an art museum, or in a case where a plurality of advertisements, digital
signage, etc. are lined up, the listening area is set so that only each commentary voice or
guidance can be heard in each place. It is possible to
[0091]
Furthermore, when presenting the sound of a plurality of contents, the content can be more
reliably separated by controlling the number and arrangement of control points so that the
sound of the other content can not be heard in the listening area of one content. .
[0092]
The series of processes described in the specification can be performed by hardware, software, or
a combination of both.
In the case of executing processing by software, a program recording the processing sequence is
installed and executed in a memory in a computer incorporated in dedicated hardware.
Alternatively, the program can be installed and executed on a general-purpose computer that can
09-05-2019
27
execute various processes.
[0093]
For example, the program can be recorded in advance on a hard disk or ROM (Read Only
Memory) as a recording medium. Alternatively, the program may be temporarily or permanently
stored in a removable recording medium such as a flexible disk, a compact disc read only
memory (CD-ROM), a magneto optical disc (MO), a digital versatile disc (DVD), a magnetic disc or
a semiconductor memory card. Can be stored (recorded). Such removable recording media can be
provided as so-called package software.
[0094]
The program may be installed from the removable recording medium to the computer, or may be
transferred from the download site to the computer wirelessly or by wire via a network such as a
LAN (Local Area Network) or the Internet. The computer can receive the program transferred in
such a manner, and install the program on a recording medium such as a built-in hard disk.
[0095]
Note that the present technology should not be construed as being limited to the embodiments of
the technology described above. The embodiments of this technology disclose the present
technology in the form of exemplification, and it is obvious that those skilled in the art can
modify or substitute the embodiments within the scope of the present technology. That is, in
order to determine the gist of the present technology, the claims should be taken into
consideration.
[0096]
Further, the acoustic signal processing device of the present technology can also be configured
as follows. (1) A division unit that performs band division of an input sound signal, and, when
sound output is performed based on the input sound signal through a plurality of speakers, the
high frequency signal component divided by the division unit is connected by the division An
09-05-2019
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acoustic signal processing apparatus comprising: a plurality of control units disposed within a
focal point of signal components below the high-frequency signal component divided by the
division unit; (2) The control unit controls the phase and the gain of the divided signal
component using the distance from the center of a plurality of speakers to the focal point, and
the divided high frequency signal component is divided by the division The acoustic signal
processing device according to (1), wherein a plurality of the signal components below the highfrequency signal component divided by the unit are arranged in the connecting point of the
signal components. (3) The sound signal processing according to (1) or (2), wherein the control
unit arranges a plurality of frequency components higher than a preset frequency component in
a focal point where signal components smaller than the high frequency signal component are
connected. apparatus. (4) The acoustic signal processing device according to (3), wherein the
wavelength of the preset frequency component is set based on the size of the head of the listener.
(5) The acoustic signal processing device according to any one of (1) to (4), wherein the input
acoustic signal is an acoustic signal of one or more contents.
[0097]
According to the acoustic signal processing device and the acoustic signal processing method
and program of this technology, the input acoustic signal is divided into bands, and when
performing acoustic output based on the input acoustic signal through the plurality of speakers,
the divided high band A plurality of focal points connecting signal components are arranged
within focal points of signal components below the divided high-frequency signal component. For
this reason, it becomes possible to arrange the in-focus area regardless of the frequency
component, and it is possible to easily improve the sound quality of the set listening area.
Therefore, it is suitable for the sound presentation system which controls a viewing-and-listening
area | region using several speakers.
[0098]
10, 10a, 10b ииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииии 21 и High
control unit, 21 ? high , 21-mid, 21-low ... phase / gain adjustment filter, 22-1 to 22-5 ... addition
unit, 30-1 to 30-5 ... speaker, 35-1 to 35-5 ииDrive part
09-05-2019
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