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JP2014060584

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DESCRIPTION JP2014060584
Abstract: A speaker arrangement design support system, a speaker arrangement design support
apparatus, a speaker arrangement design support method, and a program that can determine an
appropriate speaker arrangement with simple processing. A speaker layout design support
system 10 according to the present invention includes a dummy head unit 200 including a
speaker 110 whose arrangement state can be changed, a microphone 220 mounted on a dummy
head 210, and a microphone 220 output from the speaker 110. An impulse response
measurement unit 311 that measures an impulse response based on the measurement signal
input from the evaluation data calculation unit 312 that calculates evaluation data for
determining the arrangement of the loudspeakers 110 based on the impulse response; And a
speaker arrangement design support apparatus 300 including a speaker arrangement
determination unit 313 that determines the arrangement of the speakers 110 in which the sound
image is localized at a desired localization position. [Selected figure] Figure 14
Speaker arrangement design support system, speaker arrangement design support apparatus,
speaker arrangement design support method, and program
[0001]
The present invention relates to a speaker layout design support apparatus, a speaker layout
design support apparatus, a speaker layout design support method, and a program for designing
a speaker layout capable of localizing a sound image at a desired position.
[0002]
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1
Patent Document 1 discloses an arrangement of on-vehicle speakers for localizing a sound image.
The loudspeakers are oriented with the tonal axis substantially parallel to the front glass and
instrument panel surfaces. Furthermore, a pair of middle high-pitched speakers are provided on
the lower front of the front door and / or on the dash side. According to this configuration, it is
stated that stereo separation can be secured and sound image localization without bias can be
formed.
[0003]
Patent 2890764
[0004]
Although the method according to Patent Document 1 is suitable for music appreciation, it is
difficult for a driver to localize a sound image at a desired position.
[0005]
The warning sound in car driving was generated by a piezoelectric speaker built in the meter box,
and localization was ambiguous.
It is very important to understand what the warning sound is to immediately in driving.
Therefore, localization of the warning sound to the target object or target direction to be a target
of warning should be a great aid for understanding.
[0006]
Therefore, the inventors have previously developed a sound field generation device of Japanese
Patent Application No. 2011-089915 (unpublished at the time of application). The sound field
generation device includes a speaker that outputs sound of two or more channels, and reflects
the sound output from the speaker and outputs an acoustic signal toward a reflection unit that
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2
transmits the sound to the listener. And an audio signal in which a sound image of an audio
signal output from the speaker section and reflected by the reflection section and reached the
listener is localized as a virtual sound source at the position of the listener is input, and the input
audio A crosstalk cancellation unit that performs arithmetic processing so that crosstalk between
each channel of the acoustic signal that is reflected by the reflection unit and reaches the listener
with respect to the signal is canceled at the position of the listener ing.
[0007]
In this sound field generation apparatus, in order to determine the speaker arrangement having
the most localization effect, the vehicle shape, the interior shape around the driver (dash boat,
meter box, etc.), the sound absorption coefficient of the interior material, etc. It is necessary to do
an acoustic simulation of Because of this, it took time and effort. In the speaker arrangement in
which the simulation is omitted and is simply reflected, there is a problem that localization is not
performed in a desired direction.
[0008]
The present invention has been made in view of the above problems, and a speaker layout design
support apparatus, a speaker layout design support apparatus, a speaker layout design support
method, and a speaker layout design support apparatus capable of determining an appropriate
speaker layout with simple processing. The purpose is to provide a program.
[0009]
A speaker layout design support system (10) according to an aspect of the present invention is a
speaker (110) whose layout state can be changed and which outputs a measurement signal, a
dummy head (210), and left and right of the dummy head (210). Dummy head device (200)
comprising microphones (220) respectively attached to ear parts, and impulse response for
measuring impulse response based on the measurement signal outputted from the speaker (110)
and inputted from the microphone (200) A measurement unit (311), an evaluation data
calculation unit (312) for calculating evaluation data for determining the arrangement of the
speaker (110) based on the impulse response measured in the impulse response measurement
unit (311); Desired based on the evaluation data calculated by the data calculation unit (312)
Speaker placement determining unit which determines the placement of the speaker sound in
localization position is localized (110) (313), a speaker layout design support apparatus
comprising a (300), those with a.
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[0010]
The speaker layout design supporting apparatus (300) according to one aspect of the present
invention is an impulse based on the measurement signal output from the speaker (100)
outputting the measurement signal and input from the microphone (220) installed at the
listening position. An impulse response measurement unit (311) for measuring a response, and
evaluation data calculation for calculating evaluation data for determining the arrangement of
the speaker (100) based on the impulse response measured in the impulse response
measurement unit (311) A speaker arrangement determination unit (313) for determining the
arrangement of the speaker (110) in which the sound image is localized at a desired localization
position based on the evaluation data calculated by the unit (312) and the evaluation data
calculation unit (312) And.
[0011]
A speaker layout design support method according to an aspect of the present invention
measures an impulse response based on the measurement signal output from a speaker (110)
that outputs a measurement signal and input from a microphone (220) installed at a listening
position. An evaluation data calculation step of calculating evaluation data for determining an
arrangement of the speaker (110) based on the impulse response measured in the impulse
response measurement step; A speaker arrangement determining step of determining the
arrangement of the speakers (110) in which the sound image is localized at a desired localization
position based on the calculated evaluation data.
[0012]
The program according to one aspect of the present invention is output from the speaker (110)
that outputs the measurement signal to the computer (310) included in the speaker layout design
support apparatus (300) and from the microphone (220) installed at the listening position An
impulse response measurement step of measuring an impulse response based on the input
measurement signal; and evaluation data for determining the arrangement of the speaker (110)
based on the impulse response measured in the impulse response measurement step. Performing
an evaluation data calculation step and a speaker arrangement determination step of determining
an arrangement of the speakers (110) in which a sound image is localized at a desired
localization position based on the evaluation data calculated in the evaluation data calculation
step It is a thing.
[0013]
As described above, according to the present invention, it is possible to provide a speaker layout
design support system, a speaker layout design support apparatus, a speaker layout design
support method, and a program that can determine an appropriate speaker layout with simple
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processing. it can.
[0014]
It is a figure which shows the structure which has arrange | positioned the speaker in the
position of the meter box in a vehicle.
(A) is a graph which shows the binaural response which is a measurement result of the impulse
response in a laboratory, (b) is a graph which shows the binaural response in a vehicle.
It is a figure which shows the path | route of the reflected sound in, when a speaker is placed in
the position of a meter box.
It is a figure which shows the path | route of the reflected sound in, when a speaker is placed at
the back of a dashboard.
It is a figure which shows the path | route of the reflected sound in, when a speaker is shifted
from the position shown in FIG.
The figure shows the measurement result of the binaural response when the speaker is arranged
at the position of the meter box. The figure shows the measurement result of the binaural
response when the speaker is arranged at the back of the dashboard (a) It is a figure which
shows typically the state which exists to the right side of the speaker on either side, and (b) is a
figure which shows typically the state in which a listener exists in the middle of the speaker on
either side.
It is a side view showing an example of arrangement of a speaker in a car of a car. It is a figure
which shows the example of arrangement | positioning of the speaker in the in-vehicle of a motor
vehicle. It is a graph which shows the frequency characteristic of the binaural response which
measured the crosstalk cancellation effect at the time of aiming the speaker of a meter box
position to a driver. It is a graph which shows the frequency characteristic of the binaural
response which measured the crosstalk cancellation effect at the time of putting a speaker in the
back of a dashboard and reflecting it to a windshield. It is a graph which shows the frequency
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characteristic of the binaural response which measured the crosstalk cancellation effect at the
time of putting a speaker in a meter box position and reflecting it above the windshield. It is a
block diagram showing composition of a speaker arrangement design support system concerning
this embodiment. It is explanatory drawing of the speaker in a speaker arrangement design
support system. It is a flowchart figure which shows the speaker arrangement design support
method concerning this embodiment. It is a flowchart figure which shows the process of the
impulse response measurement step of an impulse response measurement part. It is a flowchart
which shows the evaluation data arithmetic processing in an evaluation data calculating part. It is
a table which shows the evaluation data obtained by the evaluation data arithmetic processing in
an evaluation data operation part. It is a table which shows the evaluation item by evaluation
data. It is a flowchart which shows the speaker arrangement | positioning determination process
in a speaker arrangement | positioning determination part. It is a flowchart which shows the
evaluation data arithmetic processing in an evaluation data calculating part.
[0015]
(Introduction) The inventors arrange a normal stereo speaker arrangement in the driver's seat in
a car, that is, a speaker arrangement where the driver is at the center of the L channel speaker
(Lsp) and the R channel speaker (Rsp) in front of the driver I experienced that I could not get the
usual stereo feeling. The interior of a car is an environment that is asymmetrical to the driver. For
example, in the case of a right-hand steering wheel, the distance from the driver to the right side
glass is shorter than the distance to the left side glass. Therefore, the influence of the reflection
by the side glass on the right side with respect to the driver's right ear is significant, and the right
and left reflections become uneven.
[0016]
The inventors developed the sound field generating device of Japanese Patent Application No.
2011-089915 in order to generate a desired sound field. In this sound field generation device,
the speaker is directed to the reflection unit, and the acoustic signal reflected by the reflection
unit and reaching the driver is reflected by the reflection unit and reaches the driver so as to be
equal to the acoustic signal from the virtual sound source. A crosstalk cancellation unit is
provided that performs arithmetic processing so that crosstalk between each channel of the
acoustic signal is canceled at the driver's position. However, it turned out that it is not something
that only reflection is good.
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[0017]
For example, as shown in FIG. 1, in the speaker arrangement in which the speaker is placed in
front of the meter box and inclined so that the sound reflected above the windshield reaches the
driver, the left side localization is felt smaller than the desired angle. In addition, comparing the
types of cars with different shapes, even with the same speaker arrangement, a stable sense of
localization was obtained with the wagon type, but with the hatchback type the sound image was
blurred and felt smaller than the desired angle. From this, it can be seen that the arrangement of
the speakers also greatly affects the localization of the sound image.
[0018]
[In-Car Sound Field] FIGS. 2A and 2B show impulse responses of both ears of the dummy head.
FIG. 2 (a) shows the measurement result in a laboratory (rectangular parallelepiped), and FIG. 2
(b) shows the measurement result in a closed car. LspLe and LspRe are responses of the left ear
(Le) and the right ear (Re) when the L channel speaker Lsp is driven by a pulse signal. RspLe and
RspRe are responses of the left ear and the right ear when the R channel speaker Rsp is driven by
a pulse signal. Both speakers were installed for the dummy head. (A) The response of the ear on
the driven speaker side is large in the laboratory, while (b) there is a lot of reflected sound in the
car as a whole, and the right ear is rich in reflected sound with a large amplitude. Recognize.
[0019]
FIG. 3 is a view showing a reaching path how the sound reaches the both ears (sound receiving
points) by arranging the speakers (sound source) arranged at the position of the meter box
toward the driver. In FIG. 3, two circles located at the top of the figure indicate microphones
attached to both ears of the dummy head, and two circles located at the bottom of the figure
indicate L channel speaker and R channel speaker. Is shown. The lines other than these indicate
the shape and configuration inside the vehicle. It can be obtained by performing geometric
acoustic simulation with the vehicle shape, the interior shape around the driver (dashboard,
meter box, etc.), the sound absorption coefficient of the interior material, etc. as input data. The
straight line from the speaker to the microphone in FIG. 3 is a direct sound, and the other lines
indicate the first to fifth reflected sounds reflected on glass, a ceiling, and the like. In the car, the
reflected sound has more energy than direct sound and affects the way it is heard. The highorder reflected sound reflects many reflections, and the arrival path to the sound receiving point
is also longer, so there is sound absorption and distance attenuation at the reflections, and the
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energy is small, and it is audible compared to low-order reflections. The impact on people is
small. In a normal room, the way of arrival is symmetrical, whereas in a car, when the driver is
seated on the right, it is biased to the right of the driver.
[0020]
[Regarding Arrangement of Speakers] Therefore, the inventors searched for an arrangement of
speakers in which acoustic “way of arrival” becomes symmetrical in the same manner as in the
laboratory by acoustic simulation even in a car. (Note: the speaker "placement" is not
symmetrical.) FIGS. 3 to 5 show three patterns for comparison. 1) A speaker placed at the
position of the meter box mentioned above (Fig. 3) 2) A speaker placed at the back of the
dashboard (Fig. 4) 3) Same as 2) in placing the speaker at the back of the dashboard However,
the one slightly shifted (Fig. 5)
[0021]
3 to 5 show paths of direct sound and first to fifth reflected sounds. At the position of the meter
box, reflection of the right window as shown in FIG. 3 was observed. When the speaker was
placed at the back of the dashboard (in front of the car), the effect of the right window was not
seen as shown in FIG. Although the reaching path is not completely symmetrical, it can be said
that it is nearly symmetrical. However, similarly at the back of the dashboard, as shown in FIG. 5,
the primary and secondary reflections again come from the right window at a slight shift.
[0022]
The measured responses of both ears are shown in FIG. 6 and FIG. FIG. 6 is a measurement result
when the speaker is disposed at the position of the meter box of 1), and FIG. 7 is a measurement
result when the speaker is placed at the back of the dashboard of 2). In FIG. 6, the amplitude
level of LspRe is significantly higher than the others. This means that even if you play Lsp you
can hear from the right. In FIG. 7, when LspLe and LspRe are compared, LspLe is higher, and
when RspLe and RspRe are compared, RspRe is higher, so it can be seen that it can be heard from
the regenerated side.
[0023]
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8
[Why is the path of reflected sound good in left-right symmetry] In the following, in order to
presume the ideal condition, we consider the time delay when only direct sound such as an
anechoic chamber occurs. The listener is not at an equal distance from the left and right speakers
as shown in FIG. The sound field generation device of Japanese Patent Application No. 2011089915 reproduces the reverse phase signal for canceling the crosstalk signal (RspLe) of Rsp at
the left ear from Lsp, but since the path of LspLe is longer than RspLe, it is longer than Rsp You
also have to play in advance. Pre-playing must be played before the warning sound presentation
time. Since this is impossible, conversely, it will delay the regeneration from Rsp. However, this
may cause the danger to be avoided because the warning sound is played later than the time
when the warning is desired. Therefore, it is ideal that the path difference be as small as possible,
that is, symmetrical.
[0024]
Next, consider an example in the car. As shown in FIG. 8 (b), even if the listener is at an equal
distance from the left and right speakers, the crosstalk signal LspRe is such that the reflected
sound larger than the direct sound of LspRe is delayed via the right window. It will reach the
same situation as in the previous anechoic room. Furthermore, in order to reliably cancel this
large reflected sound, it is necessary to reproduce a reverse phase signal of the same level from
Rsp and to adjust the timing so as to be canceled at the position of Re. However, since the
reflected sound from the right window of RspRe arrives at Re again later, a disturbing signal for
localization will be heard. It can be seen that such a left-right asymmetry complicates the signal
and makes crosstalk cancellation difficult. From the above, it is understood that it is preferable to
select a speaker arrangement in which the reflected sound is as symmetrical as possible.
However, in this case, the directions of arrival do not necessarily have to be symmetrical, as long
as they arrive approximately at the same time. This is because control is made to deliver the
desired signal to the positions of the ears, that is, points.
[0025]
[Speaker Orientation] Geometrical acoustic simulation is calculated using a nondirectional sound
source, but the actual speaker has directivity, and the in-vehicle sound field is a very narrow
space. It is natural to consider that many reflected sounds other than those seen in the simulation
figure have arrived, considering the wave-like behavior. Then, just like in the anechoic room
dealing with direct sound, it produces the most powerful, ie, high-energy main reflected sound in
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the car, and handles all the information of the transfer characteristics in that reflected sound. To
make other reflections weaker. In this way, I thought that an effect similar to an anechoic
chamber could be obtained.
[0026]
Therefore, in FIG. 4 of the simulation result, the reflected sound reflected at the low position of
the windshield is mainly used. For this reason, the axis of the speaker is directed 52 degrees
upward, and it is set so as to hit the reflection point of the windshield (FIG. 9, FIG. 10). FIG. 7
shows the response of both ears of the driver's seat dummy head measured in such a state. When
Lsp is driven, the amplitude of Le (LspLe) is larger than the amplitude of Re (LspRe), and when
Rsp is driven, the amplitude of Re (RspRe) is larger than the amplitude of Le (RspLe) and there
are many reflected sounds. The shape is similar to the response of the anechoic chamber.
[0027]
[Regarding the Effect of Sound Image Localization] Whether or not the sound image can be
localized at a desired position can be determined by examining whether or not the effect of
crosstalk cancellation is obtained. That is, in the second embodiment of the Japanese Patent
Application No. 2011-089915, the Lch signal (Ls in Embodiment 2) is presented only to the left
ear, and the Rch signal (Rch in Embodiment 2) is presented only to the right ear Check if it is
done.
[0028]
In each of FIGS. 11 to 13, the left figure shows the frequency characteristics of binaural response
when Lch signal is driven as a pulse signal and Rch signal as silence, and the right figure shows
Lch signal as silence and Rch signal. The frequency characteristics of the binaural response when
driven as a pulse signal are shown. In FIG. 11 to FIG. 13, LchLe is the measurement result of the
left ear when the Lch signal from the left channel speaker is driven as a pulse signal and the Rch
signal from the right channel speaker is driven as silence. LchRe is the measurement result of the
right ear when the Lch signal from the left channel speaker is driven as a pulse signal and the
Rch signal from the right channel speaker is driven as silence. RchLe is a measurement result of
the left ear when the Lch signal from the left channel speaker is driven as silence and the Rch
signal from the right channel speaker is driven as a pulse signal. RchRe is a measurement result
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10
of the right ear when the Lch signal from the left channel speaker is silenced and the Rch signal
from the right channel speaker is driven as a pulse signal. In each of the drawings, the horizontal
axis represents frequency (Hz), and the vertical axis represents sound pressure level (dB).
[0029]
It can be determined that the crosstalk cancellation effect is produced as the difference between
the two levels is larger. FIG. 11 shows measurement results when the speaker at the meter box
position is directed to the driver. FIG. 12 shows the measurement results when the speaker is
placed at the back of the dashboard and reflected by the windshield. FIG. 13 shows the
measurement results when the speaker is placed at the meter box position and reflected above
the windshield.
[0030]
In the measurement result of FIG. 11, the crosstalk cancellation effect is not obtained at 1 kHz to
3 kHz. However, in the measurement results of FIG. 12, the effect of crosstalk cancellation is
improved. In the measurement result of FIG. 13, compared with FIG. 11, the band in which the
effect is not obtained is moved to a lower band.
[0031]
When actually auditioning, the localization effect was good in the order of the windshield
reflection at the back of the dashboard in FIG. 12, the windshield reflection at the meter box in
FIG. 13, and the front of the meter box in FIG.
[0032]
[End of Introduction] As mentioned above, in order to obtain the optimum sound image
localization effect, the arrangement including the direction of the speaker is very important.
However, since the sound field in the car becomes a different sound field depending on the shape
of the vehicle and the shape of the interior, it is necessary to consider the arrangement for each
target vehicle. That is, a plurality of speaker sound sources are placed as input data using the
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11
shape and interior shape of the vehicle, the sound absorption coefficient of the interior material,
etc., and geometric sound simulation over several days is performed to obtain the speaker
position and inclination taking symmetrical reflected sound paths. I need to find out. However,
this is a very time-consuming and time-consuming task. For this reason, there has been a demand
for a design support apparatus capable of easily obtaining an optimal speaker arrangement. A
speaker arrangement design support apparatus will be described which determines an optimum
speaker arrangement by measurement of several minutes to several tens of minutes.
[0033]
Embodiment FIG. 14 is a diagram showing the configuration of the present speaker layout design
support system 10. As shown in FIG. The speaker arrangement design support system 10
includes a speaker unit 100 including the speaker arrangement drive unit 120 and the speaker
110, a dummy head unit 200 including the dummy head 210 and the microphones 220 mounted
on both ears, and a speaker arrangement design support It comprises the device 300. The
loudspeaker layout design supporting apparatus 300 in the present embodiment is realized by a
configuration including a part of software using a personal computer or the like.
[0034]
In FIG. 14, the speaker layout design supporting apparatus 300 includes a control unit 310
configured of a central processing unit (CPU), a digital signal processor (DSP) memory, and the
like, a display unit 350, an operation unit 360, an amplification unit 370, and a storage unit 380.
Configured Further, the control unit 310 includes an impulse response measurement unit 311,
an evaluation data calculation unit 312, a speaker arrangement determination unit 313, and a
speaker arrangement control unit 314, which are realized by execution of a program.
[0035]
Under the control of the speaker arrangement control unit 314, the speaker arrangement drive
unit 120 mounted on the speaker 110 can freely control the rotation of the inclination of the
speaker unit 100 using the driving force of a motor or the like (see FIG. 15). That is, the
installation angle of the speaker 110 is controlled by driving the speaker arrangement drive unit
120. The control of the speaker arrangement drive unit 120 may be controlled automatically
based on a program, or the speaker arrangement control unit 314 may be controlled based on an
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operation input from the operation unit 360.
[0036]
The amplification unit 370 amplifies the measurement signal output from the impulse response
measurement unit 311, and outputs the measurement signal to the speaker 110. The
microphone 220 is attached to both ears of the dummy head 210 installed at the driver's seat,
and the measurement signal input to the microphone 220 is amplified by a microphone amplifier
(not shown) and input to the impulse response measurement unit 311 . The microphone
amplifier may be included in the dummy head unit 200 or may be included in the speaker layout
design support apparatus 300.
[0037]
FIG. 16 is a flowchart showing a rough flow of processing executed by the speaker layout design
supporting apparatus 300. The impulse response measurement (step S1) performed by the
impulse response measurement unit 311 measures the binaural response of any speaker position
(including a change in inclination). In the evaluation data calculation (step S2) performed by the
evaluation data calculation unit 312, the evaluation data is calculated from the binaural response
of all the speaker positions. The speaker arrangement determination (step S3) performed by the
speaker arrangement determination unit 313 compares the evaluation data obtained by the
evaluation data calculation to determine the optimum speaker arrangement for sound image
localization.
[0038]
Details will be described. First, the user installs the dummy head unit 200 and the speaker unit
100 in the car. Here, the space in which the dummy head unit 200 and the speaker unit 100 are
installed may be the same space as the inside of a car of a car for which the speaker arrangement
is actually designed, or a space equivalent thereto. The user installs the dummy head unit 200
incorporating the microphone 220 in both ears at the driver's seat. The speaker 110 mounted
with the speaker arrangement drive unit 120 is placed on the dashboard. The interior of the car
is asymmetrical to the driver who is the listener.
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[0039]
At this time, for the reason described above (see the introduction), it is preferable to place the
speaker unit 100 on the back side of the dashboard. Moreover, since the initial angle of the
speaker 110 is measured by changing the angle later, it is easy to understand if it is horizontal to
the ground. If the speaker unit 100 is replaced with another place and measurement is
performed again, the best speaker position can be determined from all the measured data. The
position may be controlled by a computer by placing the speaker unit 100 on a rail or the like.
[0040]
Since the sound field generation device of Japanese Patent Application No. 2011-089915 uses at
least two or more speakers, it is necessary to measure at at least two or more positions. Further,
in the present speaker layout design support apparatus, outputs of two or more channels may be
provided to perform measurement in order.
[0041]
After installing the speaker unit 100 and the dummy head unit 200, impulse response
measurement is performed (step S1). The detailed operation of the impulse response
measurement unit 311 is shown in FIG. FIG. 17 is a flowchart showing processing in the impulse
response measurement unit 311.
[0042]
When the impulse response measurement is started, first, the current angle of the speaker 110 is
set to 0 degrees, and the angle α is set to 0 (step S11). In this state, the speaker arrangement
drive unit 120 is driven, and impulse responses are measured by the microphones 220 of both
ears (step S12). In this embodiment, the measured responses are respectively denoted as sp, the
left ear as Le, and the right ear Re, and are referred to as spLe and spRe.
[0043]
The impulse response is measured by driving a narrow pulse (15-20 μs, 50-100 V) signal and
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performing synchronous averaging using multiple averaging, driving an M-sequence noise or
pink noise signal, and the microphone 220. Cross-spectrum method to measure frequency
transfer characteristics by inverse Fourier transform by obtaining frequency transfer
characteristic from power spectrum of sound source and cross power spectrum between sound
source and receiving point using both received signal and drive signal, time-stretched pulse
signal There is a time-stretched pulse method or the like which obtains the transfer function by
convoluting the response with a drive signal whose time axis is inverted.
[0044]
The measured binaural responses spLe and spRe are stored in the storage unit 380 under such
file names that the position and inclination of the speaker 110 can be determined (step S13).
For example, save spLe and spRe in a folder called A position 0 degree.
[0045]
Next, the angle α is updated to 10 degrees (step S14). In the present embodiment, the angle of
the speaker 110 changed by the speaker arrangement driving unit 120 is set to be every 10
degrees, but before the measurement, the speaker arrangement control unit 314 can also set the
change angle of the speaker 110. Here, when the measurement is ended because the speaker
110 can not be tilted any more (NO in step S15), the process proceeds to evaluation data
calculation in step S2 of FIG.
[0046]
If the measurement is to be continued (YES in step S15), the speaker arrangement control unit
314 controls the speaker arrangement driving unit 120 to rotate the speaker 110 upward by 10
degrees (step S16). The range of the angle to be measured may be designated in advance by the
operation unit 360, and the speaker arrangement control unit 314 may automatically control the
measurement until the measurement is completed.
[0047]
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With the angle of the speaker 110 changed, the impulse response is measured again (step S12).
Save the measurement data in the folder at A position 10 degrees so that the rotation angle can
be known as before. Thus, steps S12 to S16 are repeated, and the binaural response is measured
and stored sequentially while rotating the angle of the speaker 110.
[0048]
For example, when the angle α is measured from 0 degrees to 180 degrees, 19 (A0, A1,..., A170,
A180) folders can be made for the A position. If it is desired to change the position of the speaker
unit 100 and measure it, place the speaker unit 100 at a different B position, start measurement
from the angle α = 0, change the folder name to B0,. I will save. Thus, the impulse response
measurement unit 311 measures the impulse response while changing the position of the
speaker 110 or the angle of the speaker 110.
[0049]
When all N measurements of the examination position and inclination are completed, next, the
evaluation data calculation unit 312 calculates evaluation data for determining the speaker
arrangement (step S2 in FIG. 16).
[0050]
As shown in FIG. 14, the evaluation data calculation unit 312 includes a delay time calculation
unit 3121 and an energy ratio calculation unit 3122.
Since the evaluation data calculation unit 312 calculates evaluation data for each target position,
that is, for each folder, the operation of the flowchart shown in FIG. 18 is repeated for each
folder. In addition, in the process mentioned later, each symbol has shown the following values.
Vmax_s: Maximum amplitude value of the response on the driven speaker side among the
binaural responses Vmax_a: Maximum amplitude value of the response on the opposite side to
the driven speaker among the two-ear responses Tmax_s: Time taken for Vmax_s Tmax_a: Takes
Vmax_a Time Cv = Vmax_s / Vmax_a Dt = Tmax_s−Tmax_a E0: Total energy up to the maximum
amplitude E1: Total energy after the maximum amplitude Re = E0 / E1
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[0051]
When the processing of the delay time calculation unit 3121 is started, first the direct sound
which is the first amplitude of each binaural response is searched for, and the direct sound
arrival time Tdl of spLe and the direct sound arrival time Tdr of spRe are respectively It
calculates (step S21). When the speaker unit 100 is installed on the left side, Tdl <Tdr, and for
the right side, Tdl> Tdr. Therefore, Tdl and Tdr are compared and a flag sp_flag is set. For
example, if Tdl <Tdr, sp_flag = 0, and if Tdl> Tdr, sp_flag = 1. Tdl = Tdr is set as sp_flag = 2, and is
stored in the storage unit 380 in association with the folder name (step S22).
[0052]
The responses spLe and spRe of both ears can be determined as LspLe and LspRe because they
are left speakers when sp_flag = 0, and they can be determined as RspLe and RspRe because
sp_flag = 1 because they are right speakers. In the subsequent steps, evaluation data is calculated
as LspLe and RspRe for the ear response on the speaker side and LspRe for the opposite side
response and RspLe.
[0053]
Next, the maximum amplitude is searched, and the maximum amplitude value Vmax_s and the
maximum amplitude arrival time Tmax_s of the speaker side ear response, the maximum
amplitude value Vmax_a of the opposite ear response and the maximum amplitude arrival time
Tmax_a are determined to be a value Save (step S23). Further, the ratio of the maximum
amplitude Cv = Vmax_s / Vmax_a and the time difference Dt = Tmax_s−Tmax_a are calculated
from the above values, and the values are stored in the storage unit 380 (step S24).
[0054]
Next, the energy ratio calculation unit 3122 calculates the total energy E0 before the maximum
amplitude of each response and the total energy E1 after that including the maximum amplitude,
calculates the ratio Re = E0 / E1, and stores the value It stores in 380 (step S25). It is good to
make evaluation data into a table and save like FIG. That is, evaluation data is stored in the folder
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having the above folder name.
[0055]
The speaker placement determining unit 313 determines an optimal speaker placement using the
calculated evaluation data (step S3 in FIG. 3). The speaker arrangement determining unit 313
evaluates the evaluation items shown in FIG. 20, and determines the optimum speaker
arrangement for sound image localization in the in-vehicle sound field. FIG. 20 shows the
conditions for determining the optimum speaker arrangement. The binaural response at each
position is evaluated in order from evaluation item 1. As described above (refer to the
introduction), in the in-car sound field where there are many reflections, the localization effect is
high when the speaker arrangement in which the reflected sounds arrive symmetrically in the
left-right direction. Furthermore, it is ideal to approach the response in the laboratory shown in
FIG. 2 (a). That is, an arrangement having the following features 1) to 3) must be determined. 1)
The response of the ear driving the speaker has a larger maximum amplitude. 2) The main
reflections (reflections with maximum amplitude) reach the ear immediately, and the level of
extra reflections (including direct sounds) reaching the main reflection is small and the number is
small. 3) Sound arrives symmetrically.
[0056]
The speaker placement determination unit 313 first determines whether or not to select the
optimal placement for each binaural response, and thereafter evaluates and determines the
combination of Lsp and Rsp. The flowchart of the process of the speaker arrangement |
positioning determination part 313 is shown to FIG. 21, FIG.
[0057]
When the process of the speaker placement determination unit 313 is started, the index is first
initialized to 0 (step S31). Then, using the evaluation data at A0 (A position 0 degree), it is judged
whether the maximum amplitude of the response on the speaker side is larger than the maximum
amplitude of the response on the opposite side (evaluation item 1), that is, Cv> 1. (Step S32).
[0058]
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If Cv> 1 (YES in step S32), select_flag data indicating that the selection is an optimum
arrangement is set to 1 (step S33). Cv≦1であれば(ステップS32のNO)、
select_flag=0とする(ステップS35)。 The response for which select_flag = 0
is out of the selection target of the optimal speaker arrangement. Then, the index is incremented
(step S36), and the process proceeds to the evaluation of the response of the next position
(folder).
[0059]
If select_flag = 1 is set in step S33, is the difference between the time at which the response of
the speaker side reaches the maximum amplitude and the time at which the opposite side
response reaches the maximum amplitude is negative (evaluation item 2), that is, Dt ≦ 0 Is
determined (step S34). If Dt ≦ 0 (YES in step S34), the process proceeds to step S36. On the
other hand, if Dt> 0 (NO in step S34), rewrite as select_flag = 0 (step S35). As a result, they are
not targeted for optimal speaker placement. Thereafter, the index is incremented (step S36).
[0060]
The index incremented at step S36 is compared with N (N is an integer of 2 or more) (step S37).
N is a number corresponding to the number of measurements of impulse response measurement.
If index <N (YES in step S37), the process returns to step S32 and proceeds to evaluation of the
response of the next position. Then, the processing of the above-described steps S32 to S36 is
executed for all the N responses to obtain select_flag.
[0061]
If select_flag is determined for all N responses (NO in step S37), Tmax_s + Tmax_a, the sum of
maximum amplitude arrival times of binaural responses, is sorted in ascending order only for
responses with select_flag = 1, and the storage unit 380 takes the result as sortT. (Step S38,
evaluation item 3).
[0062]
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Similarly, Re = sorting only in response to select_flag = 1, sorting in ascending order of total
energy E0 up to before the maximum amplitude / total energy E1 after the maximum amplitude,
and storing the result as sort E (step S39, evaluation item) 4).
When Re has a large value, many reflected sounds exist before the main reflected sound, which is
not preferable as a speaker arrangement for sound image localization.
[0063]
The responses ranked high in the evaluation item 3 and the evaluation item 4 are candidates for
selection of the optimal arrangement. Further, in order to obtain superiority or inferiority of each
response, the order is scored as it is, sorted in ascending order of total points P, and the result is
stored as sort P (step S40). In the present embodiment, the order is directly used as the score,
but weighting may be performed.
[0064]
Further, at this time, it may be set by the operation unit 360 as to which upper speaker position
is to be selected. For example, looking at sp_flag, 0 (Lsp) and 1 (Rsp) may be selected by the
same number, or when the number of selection targets is too large, the upper half may be set as
the target range. At this time, the response out of the selection target is updated to select_flag =
0. In the present embodiment, sortPh is stored with the upper half of sp_flag = 0 and the upper
half of sp_flag = 1 as the selection targets of the optimal arrangement (step S41).
[0065]
Next, the combination of Lsp and Rsp is evaluated. From the response to be selected, the time
Tmax_s which is the maximum amplitude of the response of the ear on the speaker side is almost
equal on the Lsp side and the Rsp side, and the values are small. . A candidate is selected one by
one from sp_flag = 1 and sp_flag = 0, and the optimal arrangement of the left and right speakers
is obtained.
[0066]
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Therefore, Tmax_s of sp_flag = 0 and Tmax_s of sp_flag = 1 are compared. It should be noted
that it is better to sort in ascending order of values at sp_flag = 0 and 1 respectively (step S42),
and keep the minimum Tmax_s as Tmax_smin and leave responses that are within Tmax_smin +
0.2 msec as selection targets (evaluation item 5). The inside of the car is very narrow, and it is
difficult to control the sound field if the left-right symmetry deviates even a little, so 0.2 msec or
less is desirable. Therefore, responses having Tmax_s <Tmax_smin + 0.2 msec are left as
selection targets (step S43).
[0067]
In the next step, the time difference Dt between the time for taking the maximum amplitude of
the speaker side and the time for taking the maximum amplitude of the opposite ear is selected
to be approximately equal on the Lsp side and the Rsp side (evaluation item 6). If the evaluation
items 5 and 6 are satisfied, it can be said that the reflected sound of Lsp and Rsp arrives
symmetrically in the left-right direction, so that it can be determined as the optimal speaker
arrangement. That is, Dt of sp_flag = 0 and Dt of sp_flag = 1 are compared. Then, the absolute
values of the differences between Dt may be sorted in ascending order (step S44), and responses
having an absolute value of the difference of Dt within 0.1 msec may be left as selection targets.
Therefore, a combination of sp_flag = 0 and 1 in which the absolute value of the difference of Dt
is within 0.1 msec is left as a selection target (step S45).
[0068]
The next step is to prioritize pairing. The combinations of sp_flag = 0 and 1 remaining in step
S45 are sorted in ascending order of the absolute value of the difference in Dt, so the optimal
arrangement is arranged from the top. That is, the speaker arrangement is determined by
prioritizing the arrival of the reflected sound in both ears from those which are symmetrical (step
S46). The first combination is displayed on the display unit 350 as, for example, folder names
“A50, C30”. That is, a pair of the left speaker 220L at the A position of 50 degrees and the
right speaker 220R at the C position of 30 degrees is the optimum arrangement. Thereby, the
optimal positions and angles of the left and right speakers are determined.
[0069]
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If the selection object becomes 0 in step S45, the display unit 350 displays a message to prompt
measurement at another position. The combination of L and R is very important, and if the
evaluation item is not satisfied, the localization effect can not be expected.
[0070]
As described above (see the introduction), when the speaker is placed in front of the dashboard
(driver's side), the direct sound is also received louder to some extent. Then, since a large
reflected sound arrives behind the direct sound, Re = E0 / E1 becomes a large value, and it is
unlikely to be a target as an optimum position. Although the windshield is curved, it does not go
as calculated on the desk, but if the main reflected sound reflected from the windshield is to be
delivered horizontally to the ground with both ears, the speaker should be as far back as possible
in the dashboard (forward Put in).
[0071]
Furthermore, from the relationship between the windshield and the binaural position, the angle
between the windshield and the horizontal surface is 45 degrees, and if it is larger than 45
degrees, the back of the speaker is directed to the driver and the speaker unit is directed to the
windshield . If the angle between the windshield and the horizontal plane is 45 degrees, then the
loudspeaker is pointed directly upwards (vertical to the horizontal plane). As the angle between
the windshield and the horizontal surface decreases from 45 degrees, the speaker should be
directed from directly above to the driver. The measurement time can be further shortened by
selecting the examination position in reference to the above. Note that the present embodiment is
an example, and is not limited to the evaluation items and the numerical values shown in FIG.
[0072]
In general, acoustic simulation is performed using a vehicle shape and an interior shape as input
data. In the present embodiment, an impulse response is automatically measured, and an optimal
arrangement is determined from actual measurement data. With regard to sound localization in a
car with a lot of reflected sound, automatic placement and optimum placement are determined
simply by placing the speakers. Usually, the input operation of geometric acoustic simulation
which took several days to several tens of days per vehicle type, and the calculation time can be
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significantly reduced. Since the optimal arrangement may be determined for each type of vehicle,
the optimal arrangement can be determined easily.
[0073]
Further, in the present embodiment, the optimal arrangement is determined only from the
binaural response without measuring whether there is a localization effect. As a result, it is
possible to determine a speaker arrangement with a high sound image localization effect without
requiring time for verifying the localization effect. Furthermore, the optimal arrangement is
conditioned and used for determining the speaker arrangement. Therefore, a sound image
position with high localization effect can be obtained by outputting a signal subjected to acoustic
signal processing so that sound can be heard from a desired position in a car.
[0074]
The above-described speaker layout design support method can optimize the speaker layout in
an asymmetric vehicle in a short time. Of course, it is also possible to determine the speaker
arrangement for vehicles and spaces other than cars. The speaker position in the vehicle is
determined based on the optimal speaker arrangement determined by the above calculation. As a
result, it is possible to obtain a speaker system capable of reliably localizing a sound image even
in an asymmetrical space with respect to the listener.
[0075]
This speaker system has left and right speakers in which signals processed to localize a sound
image at a desired position are reflected from at least one speaker to a reflection unit and
delivered to a listener. And, the difference between (the maximum amplitude arrival time of the
response of the ear on the speaker side) and (the maximum amplitude response of the response
on the opposite side of the ear on the speaker side) is substantially equal in the left and right
speakers. The maximum amplitude time of the response of the ear on the speaker side is
substantially equal in the left and right speakers, and the maximum amplitude value of the ear
response on the speaker side is larger than the maximum amplitude value of the response on the
opposite ear in each speaker In each of the speakers, the speakers are arranged such that the
difference between (the maximum amplitude arrival time of the response on the speaker side)
and (the maximum amplitude arrival time of the response on the opposite side) is negative. In
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this way, it is possible to reliably localize the sound image even in an asymmetric space.
[0076]
The above-described operation may be executed by a computer program. The above-described
computer program can be stored using various types of non-transitory computer readable media
and supplied to a computer. Non-transitory computer readable media include tangible storage
media of various types. Examples of non-transitory computer readable media are magnetic
recording media (eg flexible disk, magnetic tape, hard disk drive), magneto-optical recording
media (eg magneto-optical disk), CD-ROM (Read Only Memory), CD-R, CD-R / W, semiconductor
memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash
ROM, RAM (Random Access Memory)) are included. Also, the programs may be supplied to the
computer by various types of transitory computer readable media. Examples of temporary
computer readable media include electrical signals, light signals, and electromagnetic waves. The
temporary computer readable medium can provide the program to the computer via a wired
communication path such as electric wire and optical fiber, or a wireless communication path.
[0077]
In addition to the case where the functions of the above-described embodiment are realized by
the computer executing the program for realizing the functions of the above-described
embodiments, an OS (a program running on the computer) Implementation of the functions of
the above-described embodiments in cooperation with Operating System or application software
is also included in the embodiments of the present invention.
[0078]
As mentioned above, although this invention was demonstrated with reference to embodiment,
this invention is not limited by the above.
The configuration and details of the present invention can be modified in various ways that can
be understood by those skilled in the art within the scope of the invention.
[0079]
100: speaker unit 110: speaker 120: speaker arrangement drive unit 200: dummy head unit 210:
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dummy head 220: microphone 300: speaker arrangement design support apparatus 310: control
unit 311: impulse response measurement unit , 312: evaluation data calculation unit, 313:
speaker arrangement determination unit, 314: speaker arrangement control unit, 350: display
unit, 360: operation unit, 370: amplification unit, 380: storage unit
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