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JP2016082443

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DESCRIPTION JP2016082443
Abstract: In a closed space, a sound field is controlled so that important sound information can be
heard independently for each area. A speaker arrangement selection apparatus 400 according to
the present invention is a speaker arrangement selection apparatus 400 for selecting a plurality
of speakers used for sound field control in a closed space, and in a predetermined area among
existing speakers. The position where the linear independence is high with respect to the
predetermined area as the installation position of the first speaker selection unit 410 for
selecting the speaker with high linear independence and the at least one additional speaker
added to the existing speaker And a second speaker selection unit 420 to be selected. [Selected
figure] Figure 3
Speaker arrangement selecting apparatus, speaker arrangement selecting method, and sound
field control system
[0001]
The present invention relates to a speaker arrangement selection apparatus, a speaker
arrangement selection method, and a sound field control system in a closed space such as a car
interior of a car.
[0002]
When multiple pieces of sound information are mixed, which sound information is important
depends on the purpose of the activity.
[0003]
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1
For example, in the case where music by an audio device and voice guidance by car navigation
coexist in a car interior of a car, it is preferable that the voice guidance by car navigation be
heard preferentially at the driver's seat.
[0004]
In order to make it easier to hear the most important sound information in an environment
where a plurality of sound information are mixed, for example, when the sound guidance and the
music are mixed, the sound guidance can be heard in preference to the music. Thus, an invention
has been proposed for adjusting the sound field characteristics and the output volume (see
Patent Document 1).
[0005]
JP, 2005-167975, A
[0006]
In the vehicle interior of a car, the sound information to be preferentially heard differs depending
on the area.
For example, as described above, in the driver's seat, it is preferable to be able to hear voice
guidance by car navigation preferentially, and in the back seat it is preferable to listen to music
preferentially.
[0007]
The invention proposed in Patent Document 1 can make it possible to preferentially hear voice
guidance by car navigation at the driver's seat.
However, if voice guidance by car navigation can be preferentially heard in the driver's seat in
order to adjust the sound field characteristics and output volume for the entire vehicle interior of
the car, voice guidance by car navigation arrives at the back seat as well. In the end, the priority
for the front seats could not be secured.
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[0008]
An object of the present invention made in view of such a point is to provide a speaker
arrangement selecting device capable of controlling a sound field so that important sound
information can be heard independently for each area in a closed space, speaker arrangement
selection Method and sound field control system
[0009]
In order to solve the above-mentioned subject, a speaker arrangement selection device
concerning the present invention is a speaker arrangement selection device which chooses a
plurality of speakers used for sound field control in closed space, and is a predetermined area
among existing speakers The position where the linear independence is high with respect to the
predetermined area is provided as the installation position of the first speaker selection unit that
selects the speaker with high linear independence with respect to and the at least one additional
speaker added to the existing speaker. And a second speaker selection unit to be selected.
[0010]
Further, in the speaker arrangement selection device according to the present invention, the
second speaker selection unit is linearly independent in the middle frequency band to the high
frequency band with respect to the predetermined area as the installation position of the at least
one additional speaker. It is preferable to select a position with high sex.
[0011]
Further, in the speaker arrangement selection device according to the present invention, the
second speaker selection unit subtracts the EfI value of the non-priority region from the EfI value
of the priority region using an EfI (Effective Independence) value as an index of linear
independence. Preferably, the installation position of the at least one additional speaker is
selected such that the difference is maximized.
[0012]
In the speaker arrangement selection device according to the present invention, preferably, the
installation position of the additional speaker is selected from the back of the front seat in the
vehicle interior of the vehicle.
[0013]
Further, in order to solve the above problems, a speaker layout selection method according to the
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present invention is a speaker layout selection method for selecting a speaker used for sound
field control in a closed space, and a predetermined area is selected from existing speakers.
Selecting a speaker having high linear independence, and selecting a position having high linear
independence with respect to the predetermined area as the installation position of at least one
additional speaker added to the existing speaker. It is included.
[0014]
Further, in order to solve the above problems, a sound field control system according to the
present invention comprises a sound field control device for controlling a sound field in a closed
space, and a plurality of speakers used in the sound field control device. In the system, the
plurality of speakers is a speaker selected by a speaker arrangement selecting device, and the
speaker arrangement selecting device is a speaker having high linear independence with respect
to a predetermined area among existing speakers. A first speaker selection unit to be selected;
and a second speaker selection unit to select a position having high linear independence with
respect to the predetermined area as an installation position of at least one additional speaker to
be added to the existing speaker. And selecting the plurality of speakers used for the sound field
control device by the first speaker selection unit and the second speaker selection unit. It is an.
[0015]
Moreover, in the sound field control system according to the present invention, it is preferable to
further include a motor drive unit that changes the angle of the additional speaker.
[0016]
Further, in the sound field control system according to the present invention, the sound field
control device includes a passenger position determination unit that determines a passenger
position pattern, and the sound according to information on the passenger position pattern
determined by the passenger position determination unit. It is preferable to automatically switch
the field control parameters to optimal values.
[0017]
According to the present invention, there are provided a speaker arrangement selection device, a
speaker arrangement selection method, and a sound field control system capable of controlling a
sound field so that important sound information can be heard independently for each area in a
closed space. Can be provided.
[0018]
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BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the
sound field control system which concerns on 1st Embodiment of this invention.
FIG. 6 is a conceptual diagram showing how a sound field focused on area A and a sound field
focused on area B are combined.
It is a figure which shows schematic structure of the speaker arrangement | positioning selection
apparatus based on 1st Embodiment of this invention.
It is a figure which shows an example of arrangement | positioning of the existing speaker
installed in the vehicle interior of a motor vehicle.
It is a figure which shows a mode that a speaker with high linear independence is selected.
It is a figure which shows an example of arrangement | positioning of the selected speaker and
the speaker which was not selected.
It is a figure which shows an example of a mode that condition number falls by selecting a
speaker with high linear independence and reducing the number of speakers.
It is an example of arrangement of an additional speaker for front seat sound field concentration
control.
It is a figure which shows a mode that the additional speaker for front seat sound field
concentration control is selected.
It is a figure which shows an example of the mode of the speaker arrangement | positioning in
front seat sound field concentration control.
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It is an example of arrangement of an additional speaker for backseat field concentration control.
It is a figure which shows a mode that the additional speaker for backseat sound field
concentration control is selected.
It is a figure which shows an example of the mode of the speaker arrangement in the case of
backseat sound field concentration control.
It is a figure which shows the mode of the speaker arrangement at the time of performing control
which concentrates a sound field on the left-right both sides of a backseat. It is a figure which
shows an example of the dependence to (alpha) of condition number. It is a figure which shows
the mode of sound field isolation | separation before additional speaker installation. It is a figure
which shows a mode that the sound field isolation | separation before additional speaker
installation and the sound field isolation | separation after additional speaker installation were
compared. It is a figure which shows schematic structure of the sound field control system which
concerns on 2nd Embodiment of this invention. It is a figure which shows a mode that the
speaker which has an angle rotation function was installed. It is a figure which shows schematic
structure of the sound field control system which concerns on 3rd Embodiment of this invention.
[0019]
Hereinafter, embodiments according to the present invention will be described with reference to
the drawings.
[0020]
First Embodiment FIG. 1 is a view showing a schematic configuration of a sound field control
system 10 according to a first embodiment of the present invention.
The sound field control system 10 is a system for transmitting independent sound information in
multiple regions in a closed space such as a vehicle cabin of a car, for example. Here, "multiregion" means a plurality of regions such as a driver's seat and a rear seat. Further, the "sound
information" is, for example, audio guidance of music or car navigation. The sound field control
system 10 independently controls the sound field for each area so that, for example, voice
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guidance is easy to hear in the driver's seat and music is easy to hear in the back seat.
[0021]
The sound field control system 10 includes a sound field control device 100 that controls a
sound field in a closed space, a signal reproduction device 200 that outputs various sound
information, a plurality of speakers 300, and at least one additional speaker 350. .
[0022]
The sound field control device 100 independently controls the sound field for each area of the
plurality of pieces of sound information input from the signal reproduction device 200, and
reproduces the sound information from the plurality of speakers 300 and the additional speakers
350.
Details of the sound field control device 100 will be described later.
[0023]
For example, the signal reproduction device 200 may use various types of information recorded
in a CD or HDD, voice guidance for car navigation, telephone voice, radio broadcast, sound
information distributed from a server on the Internet, etc. to the sound field control device 100.
Output in format. Although FIG. 1 shows the configuration of one signal reproduction device
200, the signal reproduction device 200 may be a plurality of devices.
[0024]
The speaker 300 is a speaker selected to be used at the time of sound field separation control
among the existing speakers installed in a closed space. Here, "at the time of sound field
separation control" means, for example, that voice guidance of car navigation has flowed so that
voice guidance of car navigation can be heard preferentially in the driver's seat, and music is
heard preferentially in other seats In this way, control is performed to separate the sound field
for each area. In a closed space, such as a car cabin, the existing speakers are usually arranged to
be suitable for all the passengers listening to music. At the time of sound field separation control,
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it is possible to improve the sound field separation accuracy by selecting and using only the
speakers with high linear independence among the existing speakers and not using other
speakers. A selection method of selecting the speaker 300 having high linear independence from
the existing speakers will be described later.
[0025]
The additional speaker 350 is a speaker additionally installed to an existing speaker so as to be
used only at the time of sound field separation control. Although one additional speaker 350 is
shown in FIG. 1, the number of additional speakers may be arbitrary. The additional speaker 350
is installed at a position where the sound field separation control can be effectively performed.
The method of selecting the installation position of the additional speaker 350 will be described
later.
[0026]
The sound field control device 100 includes a signal separation unit 101, an environmental
sound signal adjustment unit 102, an acoustic signal generation unit 103, a signal addition unit
104, a plurality of sound output units 105, a storage unit 106, and a setting unit 107. And
[0027]
The signal separation unit 101 separates the sound information input from the signal
reproduction device 200 and outputs the sound information to the environmental sound signal
adjustment unit 102 or the acoustic signal generation unit 103 according to the sound
information.
[0028]
The signal separation unit 101 does not need to control the sound field independently, and
outputs sound information to be shared in each area to the environmental sound signal
adjustment unit 102.
In addition, the signal separation unit 101 outputs sound information that needs to
independently control the sound field to the sound signal generation unit 103.
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[0029]
Further, for example, when the sound information has a 5.1 ch format, the signal separation unit
101 can also separate the audio information distributed to the center speaker.
[0030]
The environmental sound signal adjustment unit 102 outputs the sound information input from
the signal separation unit 101 to the signal addition unit 104.
[0031]
The acoustic signal generation unit 103 generates, for each of the plurality of pieces of input
sound information, a plurality of sound signals through a filter having a filter coefficient
corresponding to a region to which each piece of sound information is to be transmitted.
The sound signal generation unit 103 is, for example, the driver's seat (area A) as the area to
which voice guidance is to be transmitted by car navigation is the driver's seat (area A). In this
case, sound information of the voice guidance is passed through a filter having a filter coefficient
for the area A (filter for the area A) to generate an acoustic signal, which is output to the signal
adding unit 104.
Here, the filter for the area A is a filter that controls the sound field of the area A as a center, for
example, a filter that controls the sound field so that it is easy to hear in the area A and hardly in
the area B.
[0032]
The acoustic signal generation unit 103 can change the filter characteristic according to the
setting by the setting unit 107.
The acoustic signal generation unit 103 reads out from the storage unit 106 the filter coefficient
necessary to change the filter characteristic in accordance with the setting by the setting unit
107.
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[0033]
The signal addition unit 104 adds the plurality of acoustic signals input from the environmental
sound signal adjustment unit 102 and the acoustic signal generation unit 103, and outputs the
result to the plurality of acoustic output units 105.
[0034]
The sound output unit 105 supplies the sound signal added by the signal addition unit 104 to the
speaker 300 and the additional speaker 350.
The number of sound output units 105 corresponds to the total number of speakers 300 and
additional speakers 350.
[0035]
The storage unit 106 stores filter coefficients of the filter used by the acoustic signal generation
unit 103. The storage unit 106 stores filter coefficients for each area. In addition, the storage
unit 106 stores a plurality of filter coefficients with different settings for each area.
[0036]
The setting unit 107 receives various settings from the user, and outputs the received settings to
the acoustic signal generation unit 103.
[0037]
Subsequently, the filter coefficients stored in the storage unit 106 will be described.
Although the filter coefficient is stored in advance in the storage unit 106, it is calculated by the
following method.
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[0038]
For example, in the cabin of a car, a plurality of microphones are installed so as to surround the
area A and the area B, with the area A as the driver's seat, the area B as the rear seat left side.
Note that this way of enclosing is an example, and the installation location of the microphone is
not limited to this. By outputting the sound from each speaker installed in the passenger
compartment and measuring the sound with each microphone, it is possible to measure the
transfer function for the combination of each speaker and each microphone. There are a plurality
of speakers and a plurality of microphones, and the relationship between the sound source and
the sound field can be defined as a transfer matrix G.
[0039]
A sound pressure response H by a sound source array configured of a plurality of sound sources
(speakers) is obtained by the following equation (1).
[0040]
Here, A F is a vector representing the relative difference between the sound source intensity and
the phase between the sound sources.
If the target sound field is given by H target, the necessary sound source conditions can be
obtained by the following equation (2).
[0041]
Here, (G) <+> is a pseudo inverse matrix of G.
[0042]
In order to optimize the input power input to the sound source, the error J between the target
sound field H target and the real sound field (sound pressure response) H (= GA F) in the
optimization problem as shown in the following equation (3) Find a solution A F that minimizes.
[0043]
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Here, H at the upper right means that it is a transposed matrix.
If Equation (3) is solved for A F with J = 0, then it can be transformed as Equation (4) below.
[0044]
Here, the regularization coefficient β is a weighted value of diagonal components, and I is an
identity matrix.
The storage unit 106 stores filter coefficients corresponding to A F thus obtained.
[0045]
Also, equation (3) has the same form as Tikhonov regularization, which reduces the condition
number of simultaneous equations to reduce the influence of noise, and the condition number
can be obtained by weighting the diagonal elements of the matrix. It is a method to lower it.
[0046]
Here, the "condition number" is an index for evaluating the sensitivity of the system to an error.
By configuring the system to reduce the number of conditions, the robustness of the system can
be enhanced. In a closed space with a small volume, such as the interior of a car, errors in the
transfer function are likely to occur. Therefore, it is effective to reduce the number of conditions
to improve robustness.
[0047]
FIG. 2 is a conceptual diagram showing how the solution of the sound pressure concentration
obtained for each control area by the multi-area sound field control is synthesized based on the
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principle of superposition. As for the sound pressure concentration problem, various methods
other than the inverse problem method have been proposed, but the inverse problem method is
applied to reflect the characteristics of the narrow internal space. First, a filter that transmits
sound to one area A and does not transmit sound to another area B is introduced. This filter is a
filter that makes sound waves from a plurality of speakers intensify in area A and the sound
pressure becomes high, and in area B, sound waves from a plurality of speakers weaken each
other and the sound pressure becomes low. The reflection in the closed space is also taken into
consideration. Next, the area A and the area B are interchanged to transmit a sound to the area B,
and a filter that does not transmit a sound to another area A is introduced. By overlapping and
using these two filters, the sound field of each region can be controlled independently. Assuming
that the target sound fields in the region A and the region B are H target, A and H target, B,
respectively, the target sound fields can be expressed by the following equations (5) and (6),
respectively.
[0048]
Here, A T is the sound source intensity of the sound source constituting the virtual sound field to
be created, and W is the transfer matrix of the free sound field.
[0049]
[Speaker Selection] At the time of sound field separation control, there are cases where the sound
field can not be separated effectively if the existing speakers normally used are used as they are.
Here, the "normal time" is a state in which the sound field separation control is not performed,
such as when all the passengers are listening to music. In order to effectively separate the sound
field, a plurality of speakers with high linear independence is selected from the existing speakers,
and an additional speaker separately installed from the existing speakers is used to control the
sound field separation. Sometimes it is useful to use these speakers as sound sources.
Hereinafter, a method of selecting a speaker to be selected and used from existing speakers at
the time of sound field separation control and a method of selecting a position of an additional
speaker used at the time of sound field separation control will be described.
[0050]
FIG. 3 is a view showing a schematic configuration of the speaker layout selection device 400
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according to the first embodiment of the present invention. The speaker arrangement selection
device 400 includes an acoustic signal transmission unit 401, an acoustic signal reception unit
402, an acoustic transfer function calculation unit 403, and a core area speaker selection unit
("first speaker selection unit" in claims) 410 And an additional speaker selection unit ("second
speaker selection unit" in claims) 420. The core area speaker selection unit 410 includes an EfI
value calculation unit 411, a number-of-speakers setting unit 412, and a speaker arrangement
selection unit 413. The additional speaker selection unit 420 includes an additional speaker E f I
value calculation unit 421, an additional speaker number setting unit 422, and an additional
speaker arrangement selection unit 423.
[0051]
The acoustic signal transmission unit 401 causes the speaker to output a sound according to a
predetermined initial signal. For example, when selecting a speaker to be used at the time of
sound field separation control from existing speakers, a predetermined initial signal is output
from the existing speakers. FIG. 4 shows an example in which fourteen speakers are disposed as
existing speakers in the cabin of a car.
[0052]
In the example shown in FIG. 4, for example, Sp1 to Sp4 are low frequency band (low frequency
band) woofers installed at the door, and Sp5 to Sp6 are mid range squawkers installed at the rear
tray. Sp10 is a mid-range squawker called a seat speaker installed in the front seat, and Sp11 to
Sp12 are two types of mid-range squawker and high-range tweeter enclosed by dotted lines
installed on the front pillar (dotted line Sp13 is a mid-range squawker located at the center of the
upper surface of the instrument panel (dashboard), and Sp14 is a heavy low-frequency
subwoofer installed in the rear tray.
[0053]
The acoustic signal reception unit 402 receives, from the microphones, acoustic signals received
by the microphones installed around, for example, the area A (driver's seat) and the area B (rear
seat left side).
The acoustic signal reception unit 402 receives an acoustic signal received by the microphone
installed around the area A from the microphone, when calculating an EfI (Effective
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Independence) value with respect to the area A. Further, when calculating the EfI value for the
area B, the acoustic signal reception unit 402 receives an acoustic signal received by the
microphone installed around the area B from the microphone. Here, the “EfI value” can be
used as an index of linear independence, and the higher the EfI value, the higher the linear
independence, and the lower the EfI value, the lower the linear independence. The method of
calculating the EfI value will be described later.
[0054]
The acoustic transfer function calculation unit 403 calculates the transfer matrix G based on the
signal input from the acoustic signal transmission unit 401 and the signal input from the
acoustic signal reception unit 402, and the EfI value calculation unit 411 or the additional
speaker EfI. The transfer matrix G is output to the value calculator 421. The acoustic transfer
function calculation unit 403 outputs the transfer matrix G to the EfI value calculation unit 411
when selecting a speaker to be used for sound field separation control from existing speakers.
Further, when selecting the position of the additional speaker used in the sound field separation
control, the acoustic transfer function calculation unit 403 outputs the transfer matrix G to the
additional speaker E f I value calculation unit 421.
[0055]
The core area speaker selection unit 410 selects a speaker to be used at the time of sound field
separation control from among existing speakers. Here, the core area indicates an area to be
controlled by multi-area sound field control. The core area speaker selection unit 410 selects a
plurality of speakers having high linear independence from a predetermined area from existing
speakers. For example, when priority control is performed to concentrate sound pressure with
the driver's seat as a priority area, a speaker having high linear independence with respect to the
driver's seat and low linear independence with respect to non-priority areas such as rear seats is
selected.
[0056]
The EfI value calculation unit 411 represents EfI representing linear independence with respect
to each of the speaker areas A and B based on the transfer matrix G input from the acoustic
transfer function calculation unit 403 and the number of speakers acquired from the number-of-
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speakers setting unit 412. Calculate the value. Here, when calculating the EfI value for the area A,
the EfI value calculation unit 411 calculates the EfI value based on the acoustic signal received
by the acoustic signal reception unit 402 from the microphone installed in the area A. Further,
when calculating the EfI value for the area B, the EfI value calculation unit 411 calculates the EfI
value based on the acoustic signal received by the acoustic signal reception unit 402 from the
microphone installed in the area B.
[0057]
The number-of-speakers setting unit 412 receives the number of speakers selected from the
existing speakers at the time of sound field separation control by input from the user, or sets it
based on, for example, a target sound field set by the user, and calculates EfI value. It outputs to
the part 411 and the speaker arrangement | positioning selection part 413.
[0058]
Based on the EfI values for the areas A and B of the speakers acquired from the EfI value
calculation unit 411, the speaker arrangement selection unit 413 selects the speakers in order
from the one with the highest EfI value.
The number of speakers selected by the speaker arrangement selection unit 413 is the number
acquired from the number-of-speakers setting unit 412. The speaker arrangement selection unit
413 sets the number of speakers with higher EfI values in the number-of-speakers setting unit
412 Select only the minutes.
[0059]
Here, a method of calculating the EfI value will be described.
[0060]
The EfI value calculation unit 411 calculates an EfI value by an EfI method (Effective
Independence Method).
The EfI method is a method of evaluating the linear independence of rows and columns
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constituting a matrix and evaluating the degree of duplication of its components. The speaker
with high linear independence means that the efficiency of transmitting the sound pressure to
the target area is high, and the necessity for performing the control to concentrate the sound
pressure is high. In addition, a speaker with low linear independence means that it is an extra
component that is less necessary. By selecting components with high linear independence, the
condition number can be lowered by eliminating surplus components with low linear
independence.
[0061]
The EfI value calculation unit 411 acquires the transfer matrix G from the acoustic transfer
function calculation unit 403, and performs singular value decomposition as in the following
equation (7).
[0062]
Here, assuming that the number of microphones is m and the number of speakers is n, the
transfer matrix G is an m × n matrix.
U is an m × m orthogonal matrix, Λ is an m × n diagonal matrix, and W is an n × n orthogonal
matrix. H at the upper right of W means that it is a transposed matrix.
[0063]
Subsequently, the EfI value calculation unit 411 generates a matrix Wa using the number of
speakers acquired from the number-of-speakers setting unit 412. Wa is an n × a matrix, where
“a” is the number of speakers acquired from the number-of-speakers setting unit 412. The EfI
value calculation unit 411 generates the matrix Wa by selecting the first to a-th column vectors
of the matrix W. For example, in the case of selecting eight speakers from fourteen speakers, n =
14 and a = 8.
[0064]
Subsequently, the EfI value calculation unit 411 calculates a vector E W of EfI values as shown in
the following equation (8).
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[0065]
Here, the function diag is a function that performs operations to extract diagonal components
and generate a column vector.
[0066]
The components of the vector E W correspond to the EfI values of each speaker and have
numerical values between 0 and 1.
The higher the EfI value, the higher the linear independence.
By selecting a speaker with a high EfI value, the condition number can be reduced, and the sound
field can be efficiently controlled.
[0067]
FIG. 5 shows an example of the EfI values of the 14 speakers calculated by the EfI value
calculation unit 411. The EfI value shown in FIG. 5 indicates the EfI value averaged in the range
of 200 Hz to 2 kHz.
[0068]
FIG. 5 (a) shows the EfI value for the region A, and FIG. 5 (b) shows the EfI value for the region B.
FIG. In the example shown in FIGS. 5A and 5B, eight speakers with high EfI values are selected
from the fourteen existing speakers. The speaker to be selected is slightly different between the
case of FIG. 5 (a) and the case of FIG. 5 (b).
[0069]
FIG. 6A shows an example of how eight speakers with high EfI values for the region A are
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selected. FIG. 6 (a) is an example of the case where the EfI value is calculated from the
measurement result by the microphone installed in the region A (the front seat right side), and
the measurement position of the microphone is a square surrounded by double lines. It is
indicated by. Black circles indicate the positions where the selected speakers are installed. Also,
the white circles indicate the positions where the unselected speakers are installed.
[0070]
FIG. 6B shows an example of how eight speakers with high EfI values for the region B are
selected. FIG. 6 (b) is an example of the case where the EfI value is calculated from the
measurement results by the microphone installed in the region B (left side of the rear seat), and
the measurement position of the microphone is a square surrounded by double lines. It is shown.
Black circles indicate the positions where the selected speakers are installed. Also, the white
circles indicate the positions where the unselected speakers are installed.
[0071]
Referring to FIGS. 6A and 6B, the sheet speakers Sp7 to Sp10 have low EfI values for the area A
and EfI values for the area B, and in all cases, they are not selected speakers (in FIG. See FIG. 4
for the positions of the seat speakers Sp7 to Sp10).
[0072]
FIG. 7 shows the result of comparison of the condition number in the case where 14 existing
speakers are installed and in the case where eight speakers having high linear independence
(that is, high EfI value) are selected.
As shown in FIG. 4, by selecting eight speakers having a high EfI value and not using six speakers
having a low EfI value, the condition number can be significantly reduced.
[0073]
In the above description, the case of selecting the number of speakers set by the number-ofspeakers setting unit 412 from the existing speakers has been described, but instead of setting
the number of speakers, the predetermined absolute value of the EfI value And a speaker having
an EfI value higher than a predetermined absolute value may be selected.
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[0074]
In the above description, the EfI value is averaged over the low frequency band to the high
frequency band (200 Hz to 2 kHz), and the speaker is selected from the one with the highest
average value of EfI. EfI values are averaged in the medium frequency band to the high frequency
band (500 Hz to 2 kHz), which is a difficult frequency band, and speakers are selected from the
higher average value of EfI in the medium frequency band to the high frequency band. Good.
In the middle to high frequency bands, in addition to the distance attenuation, the sound field
separation tends to be difficult because, for example, they are affected by reflections and
attenuations by obstacles such as a seat and an interior panel of a car cabin. However, the sound
field separation accuracy in the medium frequency band to the high frequency band can be
improved by selecting the speaker focusing on the medium frequency band to the high frequency
band. In addition, as a value of 500 Hz-2 kHz as a value of a medium frequency band to a high
frequency band is an example, you may change a frequency range suitably according to the
characteristic of a vehicle interior, and the frequency band of sound information.
[0075]
Referring back to FIG. 3 again, the function of the additional speaker selection unit 420 will be
described.
[0076]
The additional speaker selection unit 420 is, in sound field separation control, sound field
separation performance (difference in EfI value) between a priority area (space in which sound
pressure is concentrated) and a non-priority area (space in which sound pressure is suppressed).
In order to further maximize the sound pressure separation between the front and rear seats,
additional speakers in the room area near the rear passenger space where the blockage and
reflection attenuation are less affected and where car layout can be made Choose a position.
Specifically, the additional speaker selection unit 420 selects the position of the additional
speaker having high linear independence with respect to the priority area and low linear
independence with respect to the non-priority area. The functions of each block will be described
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below.
[0077]
The additional speaker EfI value calculation unit 421 calculates an EfI value based on the
transfer matrix G for the additional speakers input from the acoustic transfer function calculation
unit 403 and the number of additional speakers acquired from the additional speaker number
setting unit 422.
[0078]
The additional speaker number setting unit 422 receives an input from the user of the area
desired to be subjected to sound pressure control and the number of speakers used, and outputs
the input to the additional speaker E f I value calculation unit 421 and the additional speaker
arrangement selection unit 423.
[0079]
The additional speaker arrangement selection unit 423 determines the optimum installation
position of the additional speaker based on the EfI value acquired from the additional speaker EfI
value calculation unit 421.
The number of additional speakers selected by the additional speaker arrangement selection unit
423 is the number acquired from the additional speaker number setting unit 422, and the
additional speaker arrangement selection unit 423 has a higher difference in EfI value among the
regions for which sound pressure control is desired. The speakers are selected for the designated
number set in the additional speaker number setting unit 422.
[0080]
[Front Sound Field Centralized Control] An example of selecting an additional speaker to perform
sound field central control with the front right side as a priority area will be described below with
reference to FIGS.
Although the following description is an example in which the number of additional speakers is
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two, this is an example, and the number of additional speakers is not limited to two.
[0081]
As shown in FIG. 8, a frame is installed on the back of the driver's seat and the passenger's seat,
and 15 positions are set on the frame at 0.1 m intervals from point A to point O. Speakers are
installed at two positions selected from point A to point O, and the acoustic signal transmission
unit 401 causes the two speakers installed at the selected two positions to output sound.
[0082]
The acoustic signal reception unit 402 receives, from the microphones, acoustic signals received
by the microphones installed around the area A (driver's seat) and the area B (rear seat left side).
[0083]
The acoustic transfer function calculation unit 403 calculates the transfer matrix G based on the
signal input from the acoustic signal transmission unit 401 and the signal input from the
acoustic signal reception unit 402, and transmits the transfer matrix G to the additional speaker
E f I value calculation unit 421. Output the matrix G.
[0084]
The additional speaker E f I value calculation unit 421 is a speaker based on the transfer matrix
G input from the sound transfer function calculation unit 403 and the number of speakers (two
in this example) acquired from the additional speaker number setting unit 422. EfI values
representing linear independence with respect to regions A and B are calculated.
The additional speaker EfI value calculation unit 421 calculates an EfI value by the same method
as the EfI value calculation unit 411.
[0085]
The above procedure is performed for all two positions that can be selected from point A to point
O, and the additional speaker layout selection unit 423 determines that the average value of EfI
(for example, the average value of 200 Hz to 2 kHz) Select the combination of the two speakers
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that is high for region B and low for region B.
[0086]
FIG. 9A shows a table in which the EfI values for the front seat right side area are arranged in
descending order.
FIG. 9A shows the thirteenth to seventeenth positions in the order.
Further, FIG. 9B shows a table in which the EfI values with respect to the rear seat left side area
are arranged in ascending order. FIG. 9B shows the seventh to eleventh positions.
[0087]
Although not all combinations are shown in FIGS. 9A and 9B, the EfI value is high for area A (the
priority area, the front seat right area), and the area B (the non-priority area) , The combination
of two speakers lower for the rear seat left side area), that is, the combination of the speaker
where the difference obtained by subtracting the EfI value of the area B from the EfI value of the
area A becomes maximum at two places of A and G It is the arrangement which installed the
speaker. Position A and position G are positions separated by 60 cm, and are positions indicated
by black circles in FIG.
[0088]
FIG. 10 shows a speaker arrangement at the time of sound field separation control by front seat
sound field concentration control. Black circles are positions where the EfI value is selected to be
high among the existing speakers. A white circle is a position where the EfI value is not selected
low among the existing speakers. A shaded circle is a position selected as a position for installing
the additional speaker.
[0089]
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23
[Back Seat Sound Field Centralized Control] An example of selecting an additional speaker to
perform sound field central control with the back seat left side as a priority area will be described
below with reference to FIGS. Although the following description is an example in which the
number of additional speakers is two, this is an example, and the number of additional speakers
is not limited to two.
[0090]
As shown in FIG. 11, a frame is installed on the back of the driver's seat and the passenger's seat,
and 15 positions are set in the frame from point A to point O at intervals of 0.1 m. Speakers are
installed at two positions selected from point A to point O, and the acoustic signal transmission
unit 401 causes the two speakers installed at the selected two positions to output sound.
[0091]
The acoustic signal reception unit 402 receives, from the microphones, acoustic signals received
by the microphones installed around the area A (driver's seat) and the area B (rear seat left side).
[0092]
The acoustic transfer function calculation unit 403 calculates the transfer matrix G based on the
signal input from the acoustic signal transmission unit 401 and the signal input from the
acoustic signal reception unit 402, and transmits the transfer matrix G to the additional speaker
E f I value calculation unit 421. Output the matrix G.
[0093]
The additional speaker E f I value calculation unit 421 is a speaker based on the transfer matrix
G input from the sound transfer function calculation unit 403 and the number of speakers (two
in this example) acquired from the additional speaker number setting unit 422. EfI values
representing linear independence with respect to regions A and B are calculated.
The additional speaker EfI value calculation unit 421 calculates an EfI value by the same method
as the EfI value calculation unit 411.
10-05-2019
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[0094]
The above procedure is performed for all two positions that can be selected from point A to point
O, and the additional speaker arrangement selection unit 423 determines that the average value
of EfI (for example, the average value of 200 Hz to 2 kHz) And the combination of the lower two
speakers for the region A is selected.
[0095]
FIG. 12A shows a table in which the EfI values for the front seat right side area are arranged in
ascending order.
FIG. 12A shows the first to fifth positions.
Further, FIG. 12B shows a table in which the EfI values with respect to the rear seat left side area
are arranged in the descending order. FIG. 12B shows the first to fifth positions.
[0096]
Although not all combinations are shown in FIGS. 12 (a) and 12 (b), the EfI value is high for the
region B (priority region, rear seat left region) and the region A (non-priority region) , The
combination of the lower two speakers for the front seat right side area), that is, the combination
of the speakers where the difference obtained by subtracting the EfI value of the area A from the
EfI value of the area B becomes maximum at two points of C and D It is the arrangement which
installed the speaker. Position C and position D are positions separated by 10 cm, and are
positions shown by black circles in FIG.
[0097]
FIG. 13 shows the speaker arrangement at the time of sound field separation control by rear seat
sound field concentration control. Black circles are positions where the EfI value is selected to be
high among the existing speakers. A white circle is a position where the EfI value is not selected
low among the existing speakers. A shaded circle is a position selected as a position for installing
10-05-2019
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the additional speaker.
[0098]
FIG. 14 shows an example in which independent sound field central control is performed not
only on the left side of the rear seat but also on both sides of the rear seat. In the example shown
in FIG. 14, the number of additional speakers is four. Black circles are positions where the EfI
value is selected to be high among the existing speakers. A white circle is a position where the EfI
value is not selected low among the existing speakers. A shaded circle is a position selected as a
position for installing the additional speaker.
[0099]
In the above description of the front sound field concentration control and the rear sound field
concentration control, the EfI value is averaged over the low frequency band to the high
frequency band (200 Hz to 2 kHz), and the speaker is based on the average value of this EfI. The
EfI value is averaged in the medium frequency band to the high frequency band (500 Hz to 2
kHz), which is a frequency band in which sound field separation is difficult, and the EfI average of
the medium frequency band to the high frequency band is selected. The speaker may be selected
based on the value. In addition, it is an example to set it as 500 Hz-2 kHz as a value of a medium
frequency band to a high frequency band, and you may change a frequency range suitably
according to the characteristic of a vehicle interior.
[0100]
Moreover, in the above description of the front seat sound field concentration control and the
rear seat sound field concentration control, two speakers are installed to measure the EfI value,
and then the positions are changed to install two speakers. The procedure of measuring the EfI
value was carried out for all combinations to measure the EfI value, but the measuring procedure
is not limited to this. For example, the measurement may be performed according to the
procedure of installing 15 speakers at positions A to O and measuring the EfI values of all the
positions at one time. In addition, it is an example that it was set as 15 speakers, and another
number may be sufficient.
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[0101]
Further, in the description of the front seat sound field central control and the rear seat sound
field central control described above, the case where the position where the additional speaker is
installed is selected on the back of the driver seat and the passenger seat is described as an
example. However, this is an example, and the additional speaker may be installed at another
position. As a position where the additional speaker is installed, it is preferable to be in the
vicinity of the rear seat passenger space where the influence of the attenuation due to the
blocking object and the reflection attenuation is small.
[0102]
[Condition number regularization coefficient β dependency] The regularization coefficient β in
the equations (3) and (4) is not uniquely determined, but can take various forms. For example,
the regularization coefficient β can be in the form as shown in the following equation (9).
[0103]
Here, f is a frequency. Also, α is a constant such that α> 0.
[0104]
In FIG. 15, the condition number in the case where 14 existing speakers are installed, and 8
speakers having high linear independence (ie, high EfI value) are selected, and in the above
equation (9), α is selected. The result of the condition number in the case of 10 to 80 is shown.
As shown in FIG. 15, the condition number can be reduced by properly selecting the value of the
regularization coefficient β.
[0105]
FIG. 16 shows sound pressure levels in the range of 200 Hz to 2 kHz in the region A and the
region B. The graph shown in FIG. 16 is a graph in the case where 8 speakers are selected from
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the existing speakers, and β is adjusted in Expression (9) to select β that is the most effective
before installing the additional speakers. The black bar graph indicates the sound pressure level
of the sound source subjected to the sound field concentration control in the area A, and the
hatched bar graph indicates the sound pressure level of the sound source subjected to the sound
field concentration control in the area B.
[0106]
16 (a) shows the measurement result in the region A, and FIG. 16 (b) shows the measurement
result in the region B. FIG. In a wide range of the area A and the area B, it is possible to confirm
that the sound pressure level of the desired sound source tends to be high. However, in the
region A shown in FIG. 16A, there is a frequency band in which a sufficient effect can not be
obtained at 750 Hz to 2 kHz.
[0107]
FIG. 17 shows sound pressure levels in the range of 200 Hz to 2 kHz in area A and area B when
the above-described speaker C and speaker D (hereinafter referred to as “speaker CD”) are
installed as rear sound field concentration control. Show the added graph. The black bar graph
indicates the sound pressure level of the sound source subjected to the sound field concentration
control in the area A, and the hatched bar graph indicates the sound pressure level of the sound
source subjected to the sound field concentration control in the area B. The white bar graph
indicates the sound pressure level of the sound source subjected to the sound field concentration
control in the area B when the speaker CD is added.
[0108]
FIG. 17A shows the measurement result in the region A, and FIG. 17B shows the measurement
result in the region B. Referring to FIG. 17A, in the range of 750 Hz to 2 kHz, the influence of the
addition of the speaker CD is hardly observed. On the other hand, referring to FIG. 17B, the
addition of the speaker CD in the range of 750 Hz to 2 kHz shows an improvement in the sound
pressure level of the sound source whose sound field concentration control is performed in the
region B. This means that the sound field separation accuracy in the range of 750 Hz to 2 kH can
be improved by lowering the volume of the sound source subjected to the sound field
concentration control in the region B when the speaker CD is added.
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[0109]
As described above, according to the present embodiment, a speaker with high linear
independence is selected from the existing speakers, and a position with high linear
independence is selected and an additional speaker is installed, so that the area in the closed
space can be increased. Each sound field can be controlled so that important sound information
can be heard independently.
[0110]
In addition, the sound field separation accuracy in the middle frequency band to the high
frequency band where the sound field separation tends to be difficult by selecting the position
with high linear independence in the middle frequency band to the high frequency band and
installing the additional speaker Can be improved.
[0111]
In addition, by using the EfI value as an index of linear independence, by selecting the installation
position of the additional speaker, the difference between the EfI value in the priority area and
the EfI value in the non-priority area is maximized. Sound fields between non-priority areas can
be effectively separated.
[0112]
In addition, the sound field separation accuracy can be improved by installing the additional
speaker on the back of the seat that is less affected by the blocker and the reflection attenuation
in the cabin of the car.
[0113]
Second Embodiment FIG. 18 is a diagram showing a schematic configuration of a sound field
control system 20 according to a second embodiment of the present invention.
The sound field control system 20 includes a sound field control device 100 for controlling a
sound field in a closed space, a signal reproduction device 200 for outputting various sound
information, a plurality of speakers 300, at least one additional speaker 350, and a motor. And a
drive unit 500.
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[0114]
The sound field control system 20 according to the second embodiment is different from the
sound field control system 10 according to the first embodiment in that the motor drive unit 500
is included.
In the description of the second embodiment, points different from the first embodiment will be
mainly described, and the common contents will not be described.
[0115]
The motor drive unit 500 can change the angle (orientation angle) of the speaker 300 and / or
the additional speaker 350.
The motor drive unit 500 is installed according to the number of speakers having the function of
changing the angle.
Therefore, one or a plurality of motor driving units 500 may be provided.
[0116]
The setting unit 107 receives an input of angle setting of the speaker 300 from the user, and
outputs the received angle setting information to the motor driving unit 500.
[0117]
FIG. 19 shows that the angle of the additional speaker installed at the back of the driver's seat of
the car is rotated.
FIG. 19 (a) is a top view, and FIG. 19 (b) is a rear view. In the example shown in FIG. 19, the
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additional speaker installed at the back of the driver's seat is rotated by the motor drive unit 500
so as to turn to the left of the rear seat.
[0118]
Thus, according to the present embodiment, the sound field separation accuracy can be further
improved by making the angle of the additional speaker changeable.
[0119]
Third Embodiment FIG. 20 is a diagram showing a schematic configuration of a sound field
control system 30 according to a third embodiment of the present invention.
The sound field control system 30 includes a sound field control device 150 that controls the
sound field in a closed space, a signal reproduction device 200 that outputs various sound
information, a plurality of speakers 300, and at least one additional speaker 350. .
[0120]
The sound field control device 150 according to the third embodiment is different from the
sound field control device 100 according to the first embodiment in that a passenger position
determination unit 108 and a seat position determination unit 109 are provided. In the
description of the third embodiment, points different from the first embodiment will be mainly
described, and the common contents will not be described.
[0121]
The passenger position determination unit 108 determines a passenger position pattern, and
outputs information on the determined passenger position pattern to the setting unit 107.
[0122]
The passenger position determination unit 108 can determine a passenger position pattern by,
for example, an on / off switch by attaching and detaching a seat belt.
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The passenger position determination unit 108 can represent a passenger position pattern with
5 bits, for example, in the case of a 5-ride car. Assuming that the driver's seat is the first bit and
the passenger position of each seat is represented by bits counterclockwise, for example, 00001
(1) when there is only one driver's seat, and 00001 when there are two drivers and a passenger
seat. (3) In the case of two persons of a driver's seat and a rear seat on either side, it can
represent as 10101 (21) (the number in a parenthesis is a decimal number).
[0123]
The passenger position determination unit 108 may also determine the passenger position
pattern using an image signal of a camera attached to a rearview mirror, a pillar, a ceiling, or the
like. The passenger position determination unit 108 determines, for example, whether or not
there is a passenger for each boarding area based on an image difference amount which is a
difference between the background image and the image at the time of boarding, with the state
not boarding be able to. The threshold of the image difference amount can be arbitrarily set in
advance. Also in this case, the passenger position pattern can be represented by 5 bits.
[0124]
The seat position determination unit 109 determines the front and back position of the front seat
seated occupant, and outputs information on the front and back position of the seat to the setting
unit 107.
[0125]
The setting unit 107 outputs the information on the passenger position pattern input from the
passenger position determination unit 108 and the information on the front and back position of
the seat input from the seat position determination unit 109 to the acoustic signal generation
unit 103.
[0126]
The acoustic signal generation unit 103 stores the filter coefficient corresponding to the
passenger position pattern and the information on the front and back positions of the seat based
on the information on the passenger position pattern input from the setting unit 107 and the
information on the front and back positions of the seat. Reading from the unit 106, the
parameters of the sound field control are automatically switched to the optimum values.
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[0127]
The sound field control device 150 may be configured to include only one of the passenger
position determination unit 108 and the seat position determination unit 109 instead of both.
[0128]
As described above, according to the present embodiment, the control can be made robust by
determining the passenger position pattern and automatically switching the sound field control
parameter to the optimal value according to the passenger position pattern. .
[0129]
Further, according to the present embodiment, the control can be made robust by determining
the front and back position of the seat and automatically switching the sound field control
parameter to the optimum value according to the front and back position of the seat.
[0130]
Although the present invention has been described based on the drawings and examples, it
should be noted that those skilled in the art can easily make various changes and modifications
based on the present disclosure.
Therefore, it should be noted that these variations and modifications are included in the scope of
the present invention.
For example, the components included in each component, each step, and the like can be
rearranged so as not to be logically inconsistent, and a plurality of components or steps can be
combined or divided into one. It is.
[0131]
10, 20, 30 sound field control system 100, 150 sound field control device 101 signal separation
unit 102 environmental sound signal adjustment unit 103 acoustic signal generation unit 104
signal addition unit 105 acoustic output unit 106 storage unit 107 setting unit 108 passenger
position determination unit 109 sheet position determination unit 200 signal reproduction
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device 300 speaker 350 additional speaker 400 speaker arrangement selection device 401
acoustic signal transmission unit 402 acoustic signal reception unit 403 acoustic transfer
function calculation unit 410 core area speaker selection unit 411 EfI value calculation unit 412
speaker number setting Unit 413 Speaker arrangement selection unit 420 Additional speaker
selection unit 421 Additional speaker EfI value calculation unit 422 Additional speaker number
setting unit 423 Additional speaker arrangement selection unit 500 Motor drive unit
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