close

Вход

Забыли?

вход по аккаунту

JP2010171513

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2010171513
An object of the present invention is to make it easy to distinguish the difference between
speakers reproduced by a sound reproduction apparatus used in an audio conference or the like.
According to one embodiment of the present invention, there is provided an audio reproduction
apparatus including a first speaker including a plurality of speaker units, and a plurality of filters
for setting filter coefficients in the speaker units, and a second speaker. The directional
characteristics of the sound pressure of the first and second speakers are such that a target
direction with a large sound pressure is formed in one of the directions in which the speaker
units are arranged, and a dead angle with a small sound pressure is formed in a direction
different from the target direction. The target direction of the second speaker is directed in the
blind spot direction of the first speaker. Therefore, even if reproduced sound signals of the same
amplitude are simultaneously input to the first speaker and the second speaker, the listener can
easily know the difference in the sound from the difference in the sound pressure. [Selected
figure] Figure 1
Sound reproduction device
[0001]
The present invention relates to an audio reproduction apparatus used for an audio conference
and the like connecting different points by communication.
[0002]
For example, stereo reproduction has been used as a sound reproduction apparatus used for
04-05-2019
1
conventional audio conferences and the like.
An example is shown in Non-Patent Document 1 as an image-linked sound image localization
apparatus. The configuration of the image-linked sound image localization apparatus is shown in
FIG. 11 and its operation will be briefly described. The image-linked sound image localization
apparatus includes a display 110 and a pair of speakers 120L and 120R. The listener 130 is
located approximately at the center of the speakers 120L and 120R, and localizes the voice of
the preceding speaker between the two speakers by the difference in sound pressure between
the speakers 120L and 120R. When the preceding speaker A located in the left direction in the
display 110 speaks, the sound pressure of the speaker 120L is large, and the sound pressure of
the speaker 120R is small. In the figure, the magnitude of the sound pressure is represented by
the magnitude of an arc wave. Since the sound pressure of the speaker 120R at this time is small,
it is omitted in FIG. As described above, it is possible to grasp who is speaking on the other side
by the sound pressure difference between the left and right and the display of the display 110.
[0003]
Kitawaki Nobuhiko ed. "Communication engineering of sound-Speech and sound technology in
the multimedia age-" Corona, Inc., August 30, 1996, first edition, p. 209
[0004]
However, in the conventional stereo reproduction method, when two speakers are
simultaneously uttered and reproduced from both channels, it is not easy to distinguish and
distinguish the two persons.
That is, when speech is simultaneously reproduced from the left and right speakers at the same
volume, it is difficult to distinguish two speakers because the sounds of the left and right
speakers overlap. The present invention has been made in view of this point, and it is an object of
the present invention to provide a sound reproduction device which makes it easy to distinguish
the difference between speakers even if the reproduction sound is reproduced simultaneously.
[0005]
The sound reproduction device of the present invention comprises a first speaker and a second
04-05-2019
2
speaker. The first speaker is composed of a plurality of speaker units and a plurality of filters for
setting filter coefficients in the speaker units, and a target direction in a predetermined direction
and a dead angle direction in a direction different from the target direction. is there. The second
speaker includes a plurality of speaker units and a plurality of filters for setting filter coefficients
in the speaker units, and the target direction is directed to any one of the blind spots of the first
speaker.
[0006]
According to the present invention, since the target direction of the second speaker is directed in
the direction of the dead angle direction of the first speaker, the sound pressure is obtained even
if the reproduced sound signal of the same amplitude is simultaneously input to the first speaker
and the second speaker. It is played with big and small of. That is, the sound from the first
speaker sounds from a distance, and the sound from the second speaker sounds from a nearby
one. Therefore, the listener can easily distinguish the difference between the speakers.
[0007]
The figure which shows the function structural example of the sound reproduction apparatus
100 of this invention. The figure which shows the precondition of how to obtain ¦ require the
filter factor h. The figure which shows the specific example of the directivity characteristic of the
1st speaker 10. FIG. The figure which shows an example of the directional characteristic of the
speaker comprised with three speaker units. The figure which shows an example of the
directional characteristic obtained by the filter factor calculated by incorporating background
noise into restraint conditions. The figure which shows an example of the directivity
characteristic which made 0 degree of the speaker using three speaker units the objective
direction, and made 180 degrees a dead angle direction. The figure which shows an example of
the directivity characteristic formed of the filter factor calculated using Formula (10). FIG. 18 is a
view showing an example of the directivity characteristic of the speaker of the modification 2;
The figure which shows an example of the speaker 80 which arranged the speaker unit in the
perpendicular direction. The figure which shows the function structural example of Example 2 of
this invention which made the speaker 80 the 1st speaker. FIG. 1 is a diagram showing the
configuration of a video-linked sound image localization apparatus disclosed in Non-Patent
Document 1.
[0008]
04-05-2019
3
Hereinafter, embodiments of the present invention will be described with reference to the
drawings.
[0009]
FIG. 1 shows an example of the functional configuration of a sound reproduction apparatus 100
according to the present invention.
The sound reproduction device 100 includes a first speaker 10 and a second speaker 20. The
first speaker 10 includes a speaker unit 11, a filter 1 connected to the speaker unit 11, and a
speaker unit 12 and a filter 2 connected to the speaker unit 12. For example, the reproduction
sound signal L of one channel of the stereo signal transmitted in communication from the other
side is input to the filter 1 and the filter 2. Different filter coefficients h1 and h2 are set to the
filters 1 and 2, respectively. The directivity characteristic of the first speaker 10 is set by the
filter coefficients h1 and h2. In this example, a dead angle direction with a small sound pressure
is set on the speaker unit 12 side in the arrangement direction of the speaker units 11 and 12.
The directivity characteristics of the first speaker 10 and the second speaker 20 are
schematically shown by broken lines.
[0010]
Similar to the first speaker 10, the second speaker 20 includes the speaker unit 21 and the
speaker unit 22, and the filters 3 and 4 connected to them. For example, the reproduction sound
signal R of the other channel is input to the filters 3 and 4. The filter 3 has the same filter
coefficient h 1 as the filter 1, and the filter 4 has the same filter coefficient h 2 as the filter 2.
That is, the filter coefficients h1 and h2 are set in an inverse relationship with respect to the dead
angle direction of the first speaker 10. As a result, the large target direction of the sound
pressure of the second speaker 20 is directed to the blind spot direction of the first speaker 10.
In this example, three listeners 33a, 33b, and 33c are located ahead of the dead angle direction
of the first speaker 10 and the extension direction of the target direction of the second speaker
20.
[0011]
04-05-2019
4
When signals having the same amplitude are simultaneously input to the reproduction sound
signals L and R of the sound reproduction apparatus 100 configured as described above, the
listeners 33a to 33c make the reproduction sound L of the reproduction sound signal L smaller
and make the reproduction sound smaller. The reproduction sound R of the signal R is to be
heard loudly. That is, the sound from the first speaker whose blind spot is directed to the
listeners 33a to 33c sounds from a distance, and the sound from the second speaker whose
target direction is directed sounds from a short distance. Therefore, even if a signal of the same
amplitude is simultaneously input to both channels, the sound can be easily distinguished.
[0012]
Also, the first speaker 10 and the second speaker 20 may be arranged in a line in the direction of
the listener, or as shown in FIG. 1, the lines may be changed to arrange the lines in parallel. good.
Alternatively, the first speaker 10 and the second speaker 20 may be arranged in parallel with
the same distance between the first speaker 10 and the listeners 33a to 33c and the distance
between the second speaker 20 and the listeners 33a to 33c. . In FIG. 1, although the interval d
between the rows of the speaker units 11 and 12 and the rows of the speaker units 21 and 22 is
small, it is possible to further easily distinguish the sounds of both channels by increasing the
distance d. It is possible.
[0013]
The first speaker 10 and the second speaker 20 are generally disposed on a table 31 such as a
conference desk. Further, the display 30 may be disposed at a position where the listeners 33a to
33c face each other with the table 31 interposed therebetween.
[0014]
[Method of Setting Directional Characteristics of Speakers] A method of determining the filter
coefficient h for setting the directional characteristics of the first speaker 10 and the second
speaker 20 will be described. The idea of the precondition is shown in FIG. FIG. 2 schematically
shows how a plane wave of white noise is input to the first speaker 10 from the target direction
and the dead angle direction. Here, it is assumed that white noise is input to the speaker based
on an idea based on reciprocity theorem that the same result can be obtained even if the sound
source and the sound receiving point are reversed. According to this reciprocity theorem, even if
04-05-2019
5
it is assumed that a sound is inputted to the speaker, it is possible to obtain a filter coefficient for
outputting the sound.
[0015]
The target signal vector US shown in Equation (1) and the noise signal vector UN shown in
Equation (2) are set assuming that white noise of plane waves is input to the speaker units 11
and 12 constituting the first speaker 10 respectively. .
[0016]
Here, T represents transposition, L represents the number of samplings, and k represents
sampling time.
[0017]
The target signal vectors US1 (k) to US1 (kL) of the speaker unit 11 and the target signal vectors
US2 (k) to US2 (kL) of the speaker unit 12 are random by being white noise. The value is set to
be shifted in time by the distance between the speaker unit 11 and the speaker unit 12.
For example, the speaker units 11 and 12 are disposed at intervals of 8 cm along the target
direction, and the sampling frequency is 8 kHz.
In that condition, the vector set to US2 (k) is set delayed by 250 μs with respect to US1 (k),
assuming that the sound velocity is 340 m / s. The noise signal vector is also set with the same
idea.
[0018]
The autocorrelation matrices RS and RN of the target signal vector and the noise signal vector
are calculated by equations (3) and (4). E [•] represents an expected value / time average.
[0019]
04-05-2019
6
[0020]
Then, the target signal vector US is multiplied by the vector component at a specific time in the
target signal vector to obtain the average value S shown in the equation (5).
The filter coefficient h1 of the filter 1 connected to the speaker unit 11 and the filter coefficient
h2 of the filter 2 connected to the speaker unit 12 are calculated by Equation (6).
[0021]
[0022]
Thus, the filter coefficients h1 and h2 are the inverse matrix (RS + RN) <-1> of the sum of the
autocorrelation matrix respectively corresponding to the target signal vector US and the noise
signal vector UN arriving at a plurality of speaker units, It is a value obtained by multiplying an
average value S = E [USi (n) · US] obtained by multiplying the signal vector US by a vector
component at a specific time in the target signal vector.
[0023]
The above calculation was performed by a computer to obtain filter coefficients h1 and h2.
FIG. 3 shows the directional characteristic of the sound pressure of the first speaker 10 obtained
by the filter coefficients h1 and h2.
Concentric circles represent sound pressure and indicate 15, 10 and 5 dB from the outside. In
this example, the target direction is 180 ° and the sound pressure is about 10 dB. The 0 °
direction in the opposite direction is the dead angle direction, and the sound pressure is
approximately 0 dB. In the drawing, ● indicates a schematic position of the speaker unit. The
directivity characteristic is that whose frequency is 500 Hz. The frequency is 500 Hz for all
directional characteristics shown later.
04-05-2019
7
[0024]
[Modification 1] Although an example in which the first speaker 10 and the second speaker 20
are respectively configured by two speaker units and the respective speaker units are arranged in
a line has been described, each speaker according to the present invention Is not limited to this
configuration. The speaker unit may be a plurality of two or more, and the speakers may not be
arranged linearly.
[0025]
FIG. 4 shows an example of the directivity characteristic of a speaker configured by three speaker
units. In this example, three speaker units are arranged in a row, and the row direction is set to 0
° as the target direction, and the 90 ° direction is calculated as the dead angle direction.
Concentric circles represent true values of amplitude, which are 25, 20, 15, 10, 5 from the
outside.
[0026]
In FIG. 4, only constraint conditions of the target direction 0 ° and the dead angle direction 90
° are given. As a result, since the constraint condition of the target direction is 1, a steep valley
appears in the amplitude of the target direction. In order to improve this directivity, background
noise is incorporated into the constraint. Background noise is diffusive noise that exists in the
real environment. For example, it is an air conditioning sound that is multiply reflected indoors.
In the method of incorporating this background noise, the noise components Un (k) as shown in
equations (7), (8), and (9) as noise vectors Un of the respective speaker units as noise vectors
uncorrelated with each other. It is assumed that Un (k−L) (n = 1, 2, 3) and 2 (L + 1) zero
components are added.
[0027]
[0028]
The noise vector Un of each speaker unit is added to the noise signal vector UN shown in
04-05-2019
8
equation (2) to form an autocorrelation matrix RN, and filter coefficients are calculated.
That is, the autocorrelation matrix RN of the noise signal vector UN is set as a condition in which
uncorrelated noise is added to each of the plurality of speaker units. Using the filter coefficients
obtained in this manner, the directivity characteristic shown in FIG. 4 is improved as shown in
FIG. The concentric circles in FIG. 5 indicate values normalized with the maximum amplitude
being 1. The amplitude in the target direction 0 ° is 0.8, and the amplitude in the dead angle
direction 90 ° is 0.1 or less. When the plurality of n speaker units are provided, the dead angle
direction can be n−1.
[0029]
Although the dead angle direction is 90 degrees in FIG. 5, it is also possible to form directivity
characteristics similar to FIG. 3 even if three speaker units are used. FIG. 6 shows directivity
characteristics obtained with filter coefficients calculated by incorporating background noise into
constraint conditions, with 0 ° as the target direction and 180 ° as the blind angle direction.
Thus, a characteristic having one dead angle direction of 180 ° can also be formed.
[0030]
In addition to the method of incorporating the background noise into the constraint condition,
the product of the small positive number λ and the unit matrix I of n (L + 1) rows and n (L + 1)
columns is added to the equation (6) The calculation method shown in) can also be considered.
Here, n is the number of speaker units.
[0031]
[0032]
The directivity characteristic formed by the filter coefficients calculated and obtained by equation
(10) is shown in FIG.
04-05-2019
9
The directional characteristics shown in FIG. 7 are slightly different from the directional
characteristics shown in FIG. 5 in that the directivity in the target direction is flat. The cause of
this is that the characteristic shown in FIG. 7 is a simple method in which only the diagonal
component is added in equation (10), while the characteristics shown in FIG. 5 add equations (7)
to (9) And by the difference of the calculation method which calculates the average value of the
autocorrelation matrix. By adding Equation (7) to Equation (9), a smaller component exists
around the diagonal component.
[0033]
[Modification 2] The arrangement of the speaker units is not limited to the linear shape. For
example, it is good also as a speaker which arrange ¦ positioned five speaker units like the dice
5's. The filter coefficients were determined with the + 15 ° and -15 ° (315 °) of the speaker as
the dead angle direction and the 0 ° as the target direction. FIG. 8 shows directivity
characteristics formed by the filter coefficients. A dead angle direction in which the sound
pressure is small is formed at ± 15 °, and a large target direction of the sound pressure is
formed in the 0 ° direction. When the listener is positioned in the extension direction of the
target direction of the speaker having such directional characteristics, the sound from the
speaker is recognized as the sound heard from the listener's own shoulder. The sound
reproduction apparatus 100 may be configured using a speaker having such directional
characteristics in place of the first speaker 10.
[0034]
The speaker unit may be arranged in the vertical direction. FIG. 9 shows a speaker 80 configured
by arranging two speaker units 81 and 82 in the vertical direction. Thus, when the speaker unit
is arranged in the vertical direction and the filter coefficients h3 and h4 of the filter 83
connected to the speaker unit 81 and the filter 84 connected to the speaker unit 82 are
appropriately set by the above method, It is possible to form a blind spot in a predetermined
elevation direction. For example, assuming that the speaker 80 forms a dead angle in the
elevation direction which is in the direction of the ear of the listener 90 when the speaker 80 is
placed on a conference desk, as described in the example using the five speaker units described
above. The auditory characteristic heard from the listener's own shoulder can be obtained.
[0035]
04-05-2019
10
This speaker 80 may be used instead of the first speaker 10 of the first embodiment. A
configuration example of the sound reproduction device 200 is shown in FIG. In FIG. 10, filters
and the like are omitted. It is possible to obtain the effect of the present invention even if the first
speakers are arranged in a row in the direction orthogonal to the row with respect to the second
speaker 20 in which the speaker units are arranged in a row as described above.
[0036]
As described above, the target direction is directed to the first speaker in which the target
direction is formed in a predetermined direction and the dead angle direction is formed in the
direction different from the target direction, and to any blind spot of the first speaker. According
to the sound reproduction apparatus of the present invention provided with the second speaker,
even if reproduction sound signals of the same amplitude are simultaneously input to both
speakers, those reproduction sounds can be easily heard.
[0037]
Although the arrangement of the speaker units has been described in the five examples of the
linear shape and the size, the present invention is not limited to the arrangement of the speaker
units.
For example, the speaker unit may be arranged at the apex of a triangle, and the speaker unit can
be arranged arbitrarily. In short, it is possible to form the directivity according to the conditions
of the target signal vector and the noise signal vector set for the arrangement of the speaker
units.
[0038]
Moreover, although the row ¦ line ¦ column of the speaker unit of a 1st speaker and the row ¦
line ¦ column of the speaker unit of a 2nd speaker demonstrated the parallel and orthogonal
example, this parallel and orthogonal do not mean the exact relationship in mathematics . As
apparent from the directivity characteristics shown in FIG. 8, the variation of about ± 15 ° is
acceptable. That is, when the speaker having the directivity shown in FIG. 8 is used as the first
speaker, the target direction of the second speaker to be combined may be, for example, the + 15
° direction or the −15 ° direction. Even if there is a difference in the degree of directionality
04-05-2019
11
between the first and second speakers, it is possible to obtain the effect of the present invention.
04-05-2019
12
1/--страниц
Пожаловаться на содержимое документа