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JP2017028603

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DESCRIPTION JP2017028603
Abstract: The orientation of a directional axis of a microphone provided with a plurality of
microphone units can be easily changed. A microphone (1) includes first and second bidirectional microphone units (20) in which respective directivity axes are arranged on two
straight lines radially extending at a circumferential distance of 120 degrees through one point. ,
25 and a third bi-directional microphone unit 30 in which a pointing axis is disposed on a
straight line orthogonal to a plane formed by the two straight lines, and the first, second and
third bi-directional And a nondirectional microphone unit 10 disposed within the sound
collection area of the microphone unit. [Selected figure] Figure 3
Microphone and microphone device
[0001]
The present invention relates to a microphone and a microphone device.
[0002]
In order to pick up conversations by a plurality of speakers such as a conference, there are some
which incorporate a plurality of unidirectional microphone units in a single case.
For example, by providing three unidirectional microphone units in a housing so that their
directional axes are radially positioned at an interval of 120 degrees from each other, a
microphone capable of collecting sounds in all directions of 360 degrees is known. It is done.
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[0003]
However, in such a conventional microphone, when it is desired to change the orientation of the
directional axis, for example, in a meeting, etc., three speakers sit in front of the microphone and
on the left and right sides and can not change the installation location of the microphone. The
direction of the pointing axis could not be easily changed.
[0004]
Specifically, in the above-described example, by changing the orientations of the microphone
units in the housing so that the respective directional axes are at an angle of 90 degrees, better
sound collection can be realized.
In the conventional microphone, the directional axis is changed by physically changing the
direction of the microphone unit in the housing (see Patent Document 1), which is a complicated
mechanism. In addition, such a conventional microphone requires the user to change the
orientation of the microphone unit in the housing. Furthermore, in such a conventional
configuration, when the microphone is installed in a place where it can not be easily taken out, it
is difficult to change the direction of the directional axis of the microphone, for example, when
suspended on a ceiling or embedded on a desk. And other problems.
[0005]
Patent Documents 2 and 3 disclose devices using one omnidirectional microphone unit and two
or three bi-directional microphones. The pointing axes at are orthogonal to each other.
[0006]
JP, 2011-29766, A JP, 2008-61186, A JP, 2008-67178, A
[0007]
An object of the present invention is to provide a microphone and a microphone device capable
of easily changing the direction of the directional axis by electrical processing without physically
changing the direction of the microphone unit.
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[0008]
A microphone according to the present invention comprises: first and second bi-directional
microphone units in which the directivity axes are arranged on two straight lines extending
radially with 120 degrees of circumferential spacing through one point; A third bi-directional
microphone unit in which a pointing axis is arranged on a straight line orthogonal to a plane
formed by the two straight lines, and sound collection by the first, second and third bi-directional
microphone units And an omnidirectional microphone unit disposed in the area.
[0009]
According to the present invention, it is possible to provide a microphone and a microphone
device capable of easily changing the direction of the directional axis by electrical processing
without physically changing the direction of the microphone unit.
[0010]
FIG. 1 is a circuit diagram of a microphone device according to an embodiment of the present
invention.
It is a top view which shows the example of arrangement ¦ positioning of each microphone unit
in the microphone of the said microphone apparatus.
It is a top view which shows the example of arrangement ¦ positioning of each microphone unit,
and the directional characteristic of each microphone unit.
It is the perspective view which looked at the microphone of the example of arrangement ¦
positioning of FIG. 2 from another angle.
It is the perspective view which added the directivity characteristic figure etc. of each
microphone unit to FIG.
It is the graph which represented the directivity characteristic for every microphone unit twodimensionally. It is the graph which represented the directivity characteristic for every
microphone unit in three dimensions. It is a graph which shows the measurement data of the
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output of a nondirectional microphone unit, (a) shows a directional characteristic, (b) shows the
frequency characteristic in 0 degree, 90 degree, and 180 degree direction, respectively. It is a
graph which shows the measurement data of the output of a bidirectional microphone unit, (a)
shows a directional characteristic, (b) shows the frequency characteristic in 0 degree, 90 degree,
and 180 degree direction, respectively. It is a circuit diagram showing an example of circuit
composition of a signal amplification part. It is a graph which shows the directional characteristic
which can be obtained by embodiment of the microphone apparatus shown in FIG. In the
embodiment shown in FIG. 1, it is a graph which shows the directional characteristic of the
intermediate signal before ZS signal is synthesize ¦ combined. It is a graph which shows the data
which measured the output of the "O + LS" signal as an intermediate signal, (a) shows directivity
characteristics, (b) shows the frequency characteristic in 0 degree, 90 degrees, and 180 degrees
directions, respectively. It is a graph which shows the data which measured the output of the "O +
(-LS-RS)" signal as an intermediate signal, (a) is a directional characteristic, (b) is the frequency
characteristic in 0 degree, 90 degree, and 180 degree direction Respectively. FIG. 7 is a circuit
diagram showing another embodiment of a microphone device according to the present
invention. It is a circuit diagram showing an example of an output level adjustment circuit of a
microphone unit. It is a circuit diagram showing another example of an output level adjustment
circuit of a microphone unit. It is a circuit diagram showing another example of an output level
adjustment circuit of a microphone unit. FIG. 19 is a circuit diagram showing the circuit
configuration of FIG. 18 in further detail.
[0011]
Hereinafter, a microphone and a microphone device according to an embodiment of the present
invention will be described in detail with reference to the drawings.
[0012]
The microphone device shown in FIG. 1 has a microphone main body (hereinafter simply referred
to as a microphone) in which four microphone units are fixedly installed in a housing.
And an output signal processing unit that processes an output signal of each microphone unit.
[0013]
The four microphone units fixedly installed in the microphone 1 include one non-directional
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microphone unit 10 and first to third bi-directional microphone units 20, 25 and 30. The
physical arrangement (positional relationship) of each of the microphone units 10, 20, 25 and 30
will be described later with reference to FIGS.
[0014]
Also, in FIG. 1, in order to clarify the characteristics of the output signal of each microphone unit
and the processed signal, the direction of the directional axis, and the like, each of the threedimensional coordinates of three axes of X, Y and Z orthogonal to each other A characteristic
diagram of the signal is added, and the description thereof will be described later.
[0015]
The output signal processing unit amplifies the output signals of the respective microphone units
10, 20, 25 and 30 individually, and the signal processing units 40, 45, 50 and 55, and the
subsequent stages of the respective signal processing units 40, 45, 50 and 55. And a combining
circuit 70 as a signal combining unit provided in
[0016]
A signal amplification unit 45 as a first signal processing unit performs non-inversion
amplification and inversion amplification on the output signal of the bidirectional microphone
unit 20, and generates a non-inversion signal of positive phase (+) and an inversion signal of
negative phase (−) Are generated and output to the synthesis circuit 70.
Similarly, a signal amplification unit 50 as a second signal processing unit performs noninversion amplification and inversion amplification of the output signal of the bidirectional
microphone unit 25 to generate a non-inversion signal of positive phase (+) and an anti-phase
(−). The inverted signal of is generated and output to the synthesis circuit 70.
Hereinafter, the signal amplification units 45 and 50 are also referred to as non-inversion /
inversion amplification circuit . The signal amplification unit 40 as a third signal processing
unit amplifies the output signal of the nondirectional microphone unit 10 and outputs the
amplified signal to the combining circuit 70. The signal amplification unit 55 as a fourth signal
processing unit amplifies (non-inverting amplification) the output signal of the bidirectional
microphone unit 30 and outputs the amplified signal to the combining circuit 70. Hereinafter, the
signal amplification units 40 and 55 are also referred to as signal amplification circuits .
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[0017]
The synthesis circuit 70 synthesizes the six amplified signals supplied from the signal processing
units 40, 45, 50, 55, and outputs the synthesized signals from the three terminals A, B, C. The
output signal is supplied to an external device such as a mixer for further signal processing and
recording. The synthesis circuit 70 will be described in detail later.
[0018]
Next, the configuration of the microphone 1 will be described with reference to FIGS. 2 to 9.
[0019]
The microphone 1 shown in FIG. 2 has a casing having a substantially circular planar shape, and
the microphone units 10, 20, 25 and 30 are fixedly installed on a substrate 21 provided in the
lower case 15 of the casing. It is done.
Each of the microphone units 10, 20, 25 and 30 is of the capacitor type in this example. The
perspective view which represented the microphone 1 shown in FIG. 2 from another angle is
shown in FIG.
[0020]
2 and 4 show a state in which the upper lid of the housing is removed, and the upper lid is
screwed into a plurality of screw holes 16 formed on the side edge side of the lower case 15, It is
attached to the lower case 15.
[0021]
FIG. 3 is a diagram in which a pattern representing the directivity characteristic of each of the
microphone units 10, 20, 25, 30 and a reference line representing the positional relationship of
each of the microphone units 10, 20, 25, 30 are added to the configuration of FIG. It is.
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FIG. 5 is a perspective view corresponding to FIG. 4 to which the pattern of the directivity
characteristic, a reference line, and the like are added. As shown in FIGS. 3 and 5, nondirectional
microphone unit 10 and bidirectional microphone units 20, 25 are respectively formed on
straight lines extending radially from the center point of lower case 15 and substrate 21 at
intervals of 120 degrees. The center of the unit is located. Further, in this example, these three
microphone units 10, 20, 25 are on one plane so that the central portion of each unit is located
on the circumference centered on the central point (point 1) of the substrate 21. Is located in
[0022]
Furthermore, the bi-directional microphone units 20 and 25 have respective directivity axes on
straight lines extending radially at an angle of 120 degrees with respect to a reference line
passing from the center point of the substrate 21 to the center of the omnidirectional
microphone unit 10. Are arranged so as to be located. Therefore, the bidirectional microphone
units 20 and 25 are positioned such that their directivity axes are located on two straight lines
extending radially at 120 degrees with a circumferential distance of 120 degrees through the
center point (point 1) of the substrate 21. It is fixed on the substrate 21.
[0023]
On the other hand, a bi-directional microphone unit 30 as a third bi-directional microphone unit
is disposed on the center point of the substrate 21. In addition, the bi-directional microphone
unit 30 is disposed such that its pointing axis is orthogonal to the pointing axes of the bidirectional microphone units 20 and 25. Specifically, the directivity axes of the bidirectional
microphone units 20 and 25 are parallel to the substrate 21, while the directivity axis of the
bidirectional microphone unit 30 is directed downward of the substrate 21. It is arranged as.
[0024]
In the following, the directivity axes of the bidirectional microphone units 20 and 25 are
positioned on the XY plane using the three-dimensional coordinates of the X, Y, and Z axes
described above as appropriate, and the directivity axes of the bidirectional microphone unit 30
Will be described on the assumption that Z is on the Z axis.
[0025]
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As can be seen from FIGS. 1, 3 to 7 and FIGS. 8A and 8B showing measured data, the
nondirectional microphone unit 10 has a property of uniformly capturing an omnidirectional
sound source.
On the other hand, as can be seen from FIG. 1, FIGS. 3 to 7 and FIGS. 8A and 8B showing the
measured data, the bidirectional microphone units 20, 25 and 30 have fronts (0 deg) in the
respective units. And the other side (180 deg) has the property of strongly capturing the sound
source in two directions. In addition, the bidirectional microphone units 20, 25 and 30 have the
property that the sound source from the lateral direction (90 deg) is difficult to catch.
[0026]
In the following, in the bidirectional microphone units 20, 25 and 30, the directivity for
capturing the sound source from the front side (front, 0 deg) of each unit is a positive (+) phase,
and from the opposite side (rear, 180 deg) The directivity for capturing a sound source will be
described as a negative (-) phase. In the following, the case where the microphone 1 is installed
so as to hang from the ceiling such as a concert hall with the side on which the nondirectional
microphone unit 10 is installed facing forward will be described.
[0027]
6 and 7, the directivity pattern of the nondirectional microphone unit 10 is represented by "O",
and the directivity pattern of the left bidirectional microphone unit 20 is represented by "LS".
Also, the directivity pattern of the rightward bi-directional microphone unit 25 is represented by
RS , and the directivity pattern of the central bi-directional microphone unit 30 is represented
by ZS . Furthermore, for the bidirectional microphone units 20, 25 and 30, the positive
directivity patterns are respectively "LS +", "RS +" and "ZS +", and the negative directivity patterns
are respectively "LS-" and "RS-" And ZS- . In this example, the bidirectional microphone units
20, 25 and 30 have the same sensitivity, that is, the same output signal level when receiving a
constant sound pressure, and are also equal to the sensitivity of the nondirectional microphone
unit 10. It has become.
[0028]
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Next, with reference to FIG. 10 and the like, the signal amplification unit connected to the
microphone 1 and the synthesis circuit 70 in the rear stage of the signal amplification unit will
be described. In the following example, the signal amplification unit is configured separately from
the microphone 1, but it is also possible to incorporate the signal amplification unit or the
combining circuit 70 into the housing of the microphone 1.
[0029]
FIG. 10 shows an example of the circuit configuration of the signal amplification units 40, 45, 50,
55. As shown in FIG. 10, the signal amplification units to which the microphone units 10, 20, 25
and 30 are connected are non-inversion / inversion amplification circuits. The non-inverted /
inverted amplifier circuit shown in FIG. 10 is a balanced output circuit in which the bias resistors
R1 and R2, the emitter resistor Re, and the collector resistor Rc are connected to the transistor
51. In the non-inverted / inverted amplification circuit, the microphone unit is connected to the
base of the transistor 51, and the bias resistors R1 and R2 are connected to the base. The base
resistor R1 and the emitter resistor Re are grounded, and the voltage Vcc is applied to the
resistor R2 and the collector resistor Rc.
[0030]
The non-inverted / inverted amplification circuit amplifies the output signal of the microphone
unit by the transistor 51, and outputs a positive phase (+) signal from the emitter and a negative
phase (-) signal from the collector.
[0031]
Each signal amplification unit 40, 45, 50, 55 shown in FIG. 1 can have the circuit configuration
shown in FIG.
However, the signal amplification circuit 40 connected to the nondirectional microphone unit 10
and the signal amplification circuit 55 connected to the bidirectional microphone unit 30
combine only the non-inverted amplified signals output from the Vout + terminal shown in FIG. It
may be output to the circuit 70.
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[0032]
In this example, when the voltage levels of the input signals from the corresponding microphone
units are equal to one another, each of the signal amplification units 40, 45, 50, and 55 outputs
an amplification signal of the same level to the combination circuit 70. It is set to.
[0033]
The synthesis circuit 70 in the embodiment shown in FIG. 1 synthesizes the six amplified signals
supplied from the signal amplification units 40, 45, 50, and 55 to generate three synthesized
signals, and outputs the generated synthesized signals. Output from terminals A, B and C.
[0034]
(Output of Output Terminal A) Specifically, the synthesis circuit 70 refers to an amplified signal
(hereinafter referred to as O signal ) input from the signal amplification unit 40.
) Is referred to as a positive phase (+) amplified signal (hereinafter referred to as
input from the signal amplification unit 45.
LS signal
)
To generate an O + LS signal. Furthermore, the synthesis circuit 70 calls the signal of O +
LS as an amplified signal (hereinafter ZS signal ) input from the signal amplification unit
55. And the synthesized signal is output from the output terminal A. By this combining process,
amplified signals based on the output signals of the nondirectional microphone unit 10 and the
bidirectional microphone units 20 and 30 are combined to generate an output signal of O + LS
+ ZS .
[0035]
As shown in FIG. 1 and FIG. 11, the output signal of this O + LS + ZS intensifies the sound of the
sound source from the direction of the lower side 45 degrees of the installed microphone 1 and
the direction rotated 120 degrees left from the front side (front). It is understood that it is done.
Therefore, from the output terminal A, a unidirectional output signal having a cardioid-like
characteristic whose directivity axis is rotated 45 degrees downward and 120 degrees leftward is
obtained.
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[0036]
In order to facilitate understanding, FIGS. 1 and 12 additionally show characteristic diagrams of
the signal of O + LS as an intermediate signal. Moreover, the measurement data which
measured the intermediate signal of "O + LS" are shown in FIG. 13 (a), (b). Referring to FIG. 13A,
in the specification of the measuring device used, the direction with the highest sensitivity is 0
°, which is output based on this, but when the installation direction of the microphone 1 is the
reference, the actual direction (Angle) is a numerical value added in parentheses in FIG. 13 (a).
[0037]
In this O + LS signal, it can be seen that the directivity axis is a signal of unidirectivity by the
cardioid curve that is directed 120 degrees left with respect to the Y axis on the horizontal plane
in the XYZ three-dimensional coordinates, ie, the XY plane. Combining this O + LS signal with a
ZS signal whose directional axis points in the longitudinal direction, that is, in the Z-axis
direction, generates a unidirectional signal with a cardioid curve whose directional axis faces
downward 45 degrees and left 120 degrees as an O + LS + ZS signal. , Output terminal A.
[0038]
(Output of Output Terminal B) The synthesis circuit 70 calls the O signal input from the signal
processing unit 40 an amplified signal of positive phase (+) input from the signal processing unit
50 (hereinafter referred to as RS signal ). To generate an O + RS signal. Furthermore, the
combining circuit 70 combines the signal of O + RS with the signal ZS input from the signal
amplification unit 55, and outputs the combined signal from the output terminal B. By this
combining process, amplified signals based on the output signals of each of the nondirectional
microphone unit 10 and the bidirectional microphone units 25 and 30 are combined to generate
an "O + RS + ZS" output signal.
[0039]
As shown in FIG. 1 and FIG. 11, the output signal of this O + RS + ZS is such that the sound of the
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sound source from the direction 45 degrees below the installed microphone 1 and the direction
rotated 120 degrees to the right It is understood that it is done. In other words, the output signal
of O + RS + ZS is a unidirectional signal with a cardioid curve whose directivity axis is directed 45
degrees downward and 120 degrees right. Therefore, from the output terminal B, a unidirectional
output signal having a cardioid-like characteristic whose directivity axis is rotated 45 degrees
downward and 120 degrees rightward is obtained.
[0040]
In order to facilitate understanding, FIGS. 1 and 12 additionally show characteristic diagrams of
the signal of O + RS as an intermediate signal. In this "O + RS" signal, it can be seen that the
directivity axis is a signal of unidirectivity by the cardioid curve directed to the right by 120
degrees with reference to the Y axis on the above-mentioned XY plane. By combining this O + RS
signal with the ZS signal, a unidirectional signal with a cardioid curve pointing 45 degrees
downward and 120 degrees right is generated as the O + RS + ZS signal, and is output from the
output terminal B .
[0041]
(Output of Output Terminal C) The synthesis circuit 70 refers to the O signal input from the
signal processing unit 40 as the negative phase (−) amplified signal (hereinafter −LS signal )
input from the signal processing unit 45. To generate an O + (− LS) signal. In addition, the
synthesis circuit 70 refers to the signal of O + (− LS) as an amplified signal of negative
phase (−) input from the signal processing unit 50 (hereinafter, −RS signal ). And generate a
signal of "O + (-LS-RS)". Furthermore, the combining circuit 70 combines the signal of O + (−
LS−RS) with the signal ZS input from the signal amplification unit 55, and outputs the
combined signal from the output terminal C. By this combining process, amplified signals based
on the output signals of the nondirectional microphone unit 10 and the bidirectional microphone
units 20, 25 and 30 are combined, and the output signal of "O + (-LS-RS) + ZS" is It is generated.
[0042]
The output signal of this O + (-LS-RS) + ZS is such that the sound of the sound source from the
direction rotated 45 degrees in the front direction and downward of the installed microphone 1
is strengthened as shown in FIGS. I understand that In other words, the output signal of O + (-LS-
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RS) + ZS is a unidirectional signal with a cardioid curve whose directivity axis is downward 45
degrees and directed frontward. Therefore, from the output terminal C, a unidirectional output
signal having a cardioid-like characteristic with the directivity axis directed to the front (forward)
direction and the lower side 45 degrees can be obtained.
[0043]
In order to facilitate understanding, FIGS. 1 and 12 additionally show characteristic diagrams of
O + (− LS−RS) signal as an intermediate signal. The measurement data which measured the
output signal of O + (-LS-RS) in FIG. 14 (a), (b) are shown. Furthermore, in FIG. 1, the
characteristic diagram of the (-LS-RS) signal is also added. Here, it can be seen that the (-LS-RS)
signal is a bi-directional signal in which the directivity axis is directed to the front on the XY
plane, that is, the Y-axis direction. The O + (-LS-RS) signal in which the O signal is combined with
this (-LS-RS) signal is a signal of unidirectionality by the cardioid curve, but the direction of the
pointing axis is the same, that is, the Y-axis direction It turns out that it is facing. Then, by
combining the ZS signal with the O + (-LS-RS) signal, the output signal of the O + (-LS-RS) + ZS is a
single with a cardioid curve with the directivity axis pointing downward 45 degrees and the front
direction. A unidirectional signal is generated and output from the output terminal C.
[0044]
Thus, in the embodiment shown in FIG. 1, an output signal with a cardioid-like characteristic is
obtained from the terminal A with a 45 ° downward pointing axis and 120 ° left, and a 45 °
downward pointing axis from the terminal B. The output signal is obtained with the same
characteristic facing the right 120 degrees. Further, from the terminal C, an output signal having
a cardioid-like characteristic with the directivity axis pointing downward at 45 degrees and
facing forward is obtained.
[0045]
That is, in the microphone device shown in FIG. 1, outputs with three single directivity in which
the directional axes are all oriented 45 degrees downward and the directions in the lateral
direction of the directional axes, ie, in the XY plane are mutually shifted by 120 degrees The
signals are output from mutually different output terminals. Here, by selecting one of the output
terminals A, B, and C, the directional axis of the unidirectional microphone can be easily switched
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by electrical switching operation. Note that the number of output terminals to be selected is not
limited to one, and a plurality of output terminals may be selected.
[0046]
Next, another embodiment of the microphone device having a different configuration of the
synthesis circuit will be described with reference to FIG.
[0047]
(Output of Output Terminal A) In FIG. 15, the synthesis circuit 70 includes the O signal input
from the signal amplification unit 40, the LS signal input from the signal amplification unit 45,
and the -RS signal input from the signal amplification unit 50. A ZS signal input from the signal
amplification unit 55 is synthesized.
The combined signal is output from the output terminal A as a signal of O + (LS-RS) + ZS.
[0048]
The output signal of this O + (LS-RS) + ZS is 90 ° left of the installed microphone 1 and the
sound of the sound source from the 45 ° downward direction is intensified, and the opposite
side, that is, the 45 ° rightward direction from the 45 ° upward Has the characteristic that the
sound of the sound source of Accordingly, the signal of O + (LS-RS) + ZS is a directional axis
rotated 30 degrees to the right as compared with the signal of O + LS + ZS output from the
output terminal A of the combining circuit of FIG.
[0049]
In order to facilitate understanding, FIG. 15 additionally shows characteristic diagrams of the (LSRS) signal and the O + (LS-RS) signal as intermediate signals. First, it can be seen that the (LS-RS)
signal is a bi-directional signal in which the directivity axis is directed to the left by 90 degrees.
By combining the O signal with the (LS-RS) signal, the O + (LS-RS) signal becomes a unidirectional
signal based on the cardioid curve whose directivity axis is directed to the left by 90 degrees.
Furthermore, by combining the ZS signal with the O + (LS-RS) signal, the pointing axis of the O +
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(LS-RS) signal located on the XY plane is rotationally moved downward 45 degrees. Therefore,
from the output terminal A, a unidirectional output signal having a cardioid-like characteristic
with the directivity axis directed to the left 90 degrees and the lower 45 degrees can be obtained.
[0050]
(Output of output terminal B) The synthesis circuit 70 includes the O signal input from the signal
amplification unit 40, the −LS signal input from the signal amplification unit 45, the RS signal
input from the signal amplification unit 50, and the signal amplification unit 55. And the ZS
signal input from. The combined signal is output from the output terminal B as a signal of O + (LS + RS) + ZS.
[0051]
The output signal of this O + (-LS + RS) + ZS is 90 degrees right of the installed microphone 1 and
the sound of the sound source from the lower 45 direction is intensified, and this opposite side,
that is, from the upper 45 direction It has the characteristic that the sound of the sound source
can be weakened. Therefore, the signal of O + (-LS + RS) + ZS is the one whose directional axis is
rotated 30 degrees to the left as compared with the signal of O + RS + ZS output from the output
terminal B of the combining circuit of FIG.
[0052]
In order to facilitate understanding, FIG. 15 additionally shows characteristic diagrams of the (-LS
+ RS) signal and the O + (-LS + RS) signal as intermediate signals. First, it can be seen that the (-LS
+ RS) signal is a bi-directional signal in which the directional axis is directed to the right by 90
degrees. By combining the (-LS + RS) signal with the O signal, the signal becomes an O + (-LS +
RS) signal that is a unidirectional signal with a cardioid curve with the pointing axis directed to
the right by 90 degrees. Furthermore, by combining the ZS signal with the O + (−LS + RS) signal,
the pointing axis of the O + (−LS + RS) signal located on the XY plane is rotationally moved
downward 45 degrees. Therefore, from the output terminal B, a unidirectional output signal
having a cardioid-like characteristic with the directivity axis directed to the right 90 degrees and
the lower 45 degrees can be obtained.
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[0053]
(Output of Output Terminal C) For the negative phase (-) amplified signal (-RS signal) input from
the signal amplifying unit 50, the -LS signal from the signal amplifying unit 45, and the signal are
the same as in FIG. The O signal from the amplification unit 40 and the ZS signal from the signal
amplification unit 55 are combined. Therefore, the same O + (-LS-RS) + ZS signal as in FIG. 1 is
output from the output terminal C.
[0054]
Thus, in the embodiment shown in FIG. 15, from the output terminal A, an output signal having a
cardioid-like characteristic in which the directivity axis is rotated 90 degrees to the left and 45
degrees downward is obtained. Further, from the output terminal B, an output signal having a
cardioid-like characteristic in which the directivity axis is rotated 90 degrees to the right and 45
degrees downward is obtained. Further, from the output terminal C, an output signal having a
cardioid characteristic in which the directivity axis is turned forward by 45 degrees is obtained.
[0055]
That is, in the microphone device shown in FIG. 15, the outputs with three single directivity in
which the directional axes are all 45 degrees downward and the directions in the lateral direction
of the directional axes, that is, in the XY plane are mutually offset by 90 degrees The signals are
output from mutually different output terminals. Also in the embodiment shown in FIG. 15, the
directional axis of the unidirectional microphone can be easily switched by selecting one of the
output terminals A, B and C by the electrical switching operation. The number of output
terminals to be selected may be more than one as described above.
[0056]
As described above, in the microphone 1 according to the present embodiment, the directional
axes of the pair of left and right bi-directional microphone units 20 and 25 pass through one
point and extend on two straight lines radially extending at circumferential intervals of 120
degrees. Is located in In addition, in the microphone 1, the directivity axis of the directional
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microphone unit 30 is disposed on a straight line orthogonal to the XY plane formed by the two
straight lines, that is, on the Z axis. Furthermore, in the microphone 1, the directional
microphone unit 10 is disposed within the sound collection area of each bi-directional
microphone unit 20, 25, 30. According to the microphone 1 having such a basic configuration,
the direction of the directional axis can be easily changed by electrical processing.
[0057]
That is, in this embodiment, as in the conventional configuration using three unidirectional
microphone units, there is no need to change the physical position of the microphone unit in the
housing in order to change the orientation of the directional axis. There is no need to touch the
microphone 1. Therefore, according to the present embodiment, it is not necessary to provide a
complicated mechanism for changing the position of the microphone unit as in the prior art, and
furthermore, the restriction on the installation place of the microphone is also eliminated.
[0058]
The circuits shown in FIGS. 1 and 15 have been described as separate embodiments. However,
the configuration of the combining circuit 70 shown in FIG. 1 and the configuration of the
combining circuit 70 shown in FIG. 15 may be switched by a changeover switch.
[0059]
When a changeover switch is used, the connection switching of FIGS. 1 and 15 for changing the
direction of directivity, that is, the on / off state can be switched at one time by a physical
interlock switch.
[0060]
As another example, switching of connection of FIG. 1 and FIG. 15 may be separately switched by
a plurality of switches.
In this case, obtain an output signal with a cardioid-shaped characteristic in which one rotates in
the horizontal direction 90 degrees and the lower 45 degrees and the other rotates in the
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horizontal direction 120 degrees and the lower 45 degrees about the pointing axis. Can.
[0061]
Further, as another example, the switching of the above-described switch can be softwarecontrolled by using a personal computer (PC) or the like.
[0062]
(Level Adjustment Unit) Further, in order to continuously change the directivity characteristics of
the signals output from the respective output terminals A, B and C, the microphone units (10 to
30) are connected to the signal amplification unit (40 to 55). And a level adjustment unit that
adjusts the level of the output signal of
[0063]
FIG. 16 shows a circuit configuration example in which a level adjustment unit is provided on
each output line of the signal amplification units 40, 45, 50, 55.
The level adjustment unit 80 is a circuit in which an input resistance Ri is connected to the
negative side input terminal of the operational amplifier 81 and a feedback resistance is
connected between the output side of the operational amplifier 81 and the negative side input
terminal, A variable resistor VRf is used as a feedback resistor.
In the level adjustment unit 80, the gain of the operational amplifier is determined by the ratio
between the resistance value set by the variable resistor VRf and the resistance value of the input
resistance Ri. Therefore, by providing the level adjustment unit 80 in each output line of the
signal amplification units 40, 45, 50, 55, the output signal level of each microphone unit can be
adjusted by adjusting the variable resistor VRf of the level adjustment unit 80. .
[0064]
FIG. 17 shows a circuit configuration example in which a level adjustment unit is provided in the
signal amplification unit (non-inversion / inversion amplification circuit) 40, 45, 50, 55 to which
the microphone units 10, 20, 25, 30 are connected. This non-inverted / inverted amplifier circuit
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is such that the collector resistance connected to the transistor 51 in the non-inverted / inverted
amplifier circuit shown in FIG. 10 is a variable resistor VRc. According to the non-inverted /
inverted amplification circuit shown in FIG. 17, by adjusting the resistance value of the variable
resistor VRc, the output signal level of the negative phase (−) signal of the microphone unit, and
further the positive phase (+) The ratio of output signal levels can be adjusted.
[0065]
Furthermore, a circuit equivalent to the level adjustment unit shown in FIG. 16 can be provided
at each subsequent stage of the output terminals A to C of the synthesis circuit 70. With this
configuration, the output levels of the three-phase signals supplied to the external device can be
adjusted individually.
[0066]
(Microphone sensitivity adjustment unit) Furthermore, in order to continuously change the
directivity characteristics of the signals output from the respective output terminals A, B and C,
the microphone units (10 to 30) and the signal amplification units (40 to 55) And a sensitivity
adjustment unit of the microphone unit. FIG. 18 illustrates an example of a circuit configuration
of a sensitivity adjustment unit using a condenser microphone as the microphone unit 100.
[0067]
The sensitivity adjustment unit shown in FIG. 18 has an impedance conversion unit 90 using an
FET 91, resistors R3 and R4, and a capacitor 92, and has a configuration in which the output
voltage of the phantom power supply 93 for supplying polarized voltage to the capacitor
microphone is variable. It has become.
[0068]
The phantom power supply 93 is supplied from the mixer side, but is drawn in a simplified
manner as if it is near the microphone unit 100 in FIG.
Voltage adjustment of the phantom power supply 93 can be performed on the mixer side.
03-05-2019
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[0069]
Further, although the phantom power source itself is drawn as a variable voltage power source in
FIG. 18, actually, the voltage of the phantom power source is converted via a DC-DC converter or
a regulator. A specific circuit configuration for changing the voltage of the phantom power
supply is shown in FIG. In the circuit shown in FIG. 19, the phantom power supply 93 and the
variable resistor R5 are connected in parallel, and one terminal of the microphone unit 100 is
connected to the variable terminal of the variable resistor R5, whereby the voltage value applied
to the microphone unit 100 is Adjusted. By adjusting the output voltage value of the phantom
power source 93 in this manner, the sensitivity of the microphone unit is adjusted, and the signal
level output from the microphone unit to the signal amplification unit is adjusted.
[0070]
By providing the sensitivity adjustment units shown in FIGS. 18 and 19 to the microphone units
10, 20, 25 and 30 shown in FIGS. 1 and 15, the microphone units 10, 20 and 25 in the signal
synthesized by the synthesis circuit 70. , 30's influence changes. As a result, the direction of the
unidirectional directivity axis outputted from each of the terminals A, B and C changes
continuously, and at the same time, the directivity pattern also changes.
[0071]
For example, in the nondirectional microphone unit 10, by setting the output voltage value of the
phantom power supply 93 large, the pattern characteristics of the signals output from the output
terminals A to C become more omnidirectional. Conversely, by setting the output voltage value of
the phantom power supply 93 small, the degree of reflection of the nondirectional pattern
characteristics in the signals output from the output terminals A to C becomes small.
[0072]
As described above, by arbitrarily adding the sensitivity adjustment unit and the level adjustment
unit, it is possible to adjust the directivity characteristics of the output signal supplied to the
external device individually and continuously.
03-05-2019
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[0073]
Specifically, by adjusting the combining ratio of the outputs of the bidirectional microphone units
20 and 25, the pointing axis can be continuously changed in any direction on the XY plane.
For example, when the composite ratio of the bidirectional microphone unit 25 with respect to
the bidirectional microphone unit 20 is continuously increased, the direction of the directional
axis of the signal to be synthesized is continuous toward the directional axis of the bidirectional
microphone unit 25. Can be inclined.
[0074]
Also, by adjusting the combining ratio of the outputs of the bidirectional microphone units 20, 25
or 30 with respect to the nondirectional microphone unit 10, the pattern shape of the directional
characteristics can be freely changed from the cardioid to the hypercardioid etc it can.
[0075]
Furthermore, by adjusting the combining ratio of the outputs of the bidirectional microphone
unit 20 or 25 with respect to the bidirectional microphone unit 30, it is possible to continuously
change the inclination of the directional axis in the Z-axis direction.
For example, when the composite ratio of the bi-directional microphone unit 30 to the bidirectional microphone unit 20 is continuously increased, the direction of the directional axis of
the signal to be synthesized is the directional axis (Z-axis) of the bidirectional microphone unit 30
Are continuously inclined toward the
[0076]
The microphone and the microphone device according to the present invention are expected to
be microphones installed in concert halls and outdoor venues for sound collection such as music
performance, table mounted microphones suitable for sound collection for meetings, and many
other applications. .
03-05-2019
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[0077]
The connection mode in the combining circuit 70 shown and described in FIGS. 1 and 15, that is,
the combining mode of each signal is an example.
The synthesis circuit 70 synthesizes at least one of the non-inverted signal and the inverted
signal output from the bidirectional microphone units 20 and 25 with the output signals of the
omnidirectional microphone unit 10 and the bidirectional microphone unit 30. What is
necessary. With this configuration, two or more output signals having pointing axes in different
directions can be generated.
[0078]
The number of output terminals of the combining circuit 70 may be plural, and the combination
of signals to be combined is arbitrary. In the combining circuit 70, a terminal for outputting the
output signals of the microphone units 10, 20, 25 and 30 as they are without being combined
and a pattern of the direction of the directional axis and the directional pattern mentioned above
are continuously changed and output. Terminals may be additionally provided. As described
above, by increasing the number of signals output from the synthesis circuit 70, it is possible to
perform multi-channel sound collection.
[0079]
The switching of the direction of the directional axis according to the output characteristics in
the output signal processing unit, that is, the synthesis mode of the input signal, the adjustment
of the microphone sensitivity, etc. may be performed manually or manually. . For example, as for
sound field collection, the direction of the sound source may be detected, and switching or
adjustment may be automatically performed so as to be the direction of the directional axis
corresponding to the detected sound source direction. In this case, the output wiring of each
microphone unit 10, 20, 25, 30 is branched and connected to a control device such as a PC, and
based on the output of each microphone unit 10, 20, 25, 30 detected by the control device.
Control can be performed. This control includes switching of the above-described switch of the
combining circuit 70, combining of the signals in the combining circuit 70, and adjustment of the
resistance value of the various variable resistors described above.
03-05-2019
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[0080]
In the present embodiment, an example in which each of the microphone units 10, 20, 25 and 30
has a capacitor type has been described, but the present invention is not limited to this. For
example, any one or more of the three bi-directional microphone units 20, 25, 30 may be a
ribbon microphone unit.
[0081]
In the present embodiment, the microphone units 10, 20, 25 are positioned on three straight
lines which radially extend at 120 degrees with respect to each other at 120 degrees through the
one point (the center point of the substrate 21). The position of the microphone unit 10 is not
limited to this. The position of the omnidirectional microphone unit 10 may be disposed within
the sound collection area of the other microphone units 20, 25, 30. Therefore, the
omnidirectional microphone unit 10 can be provided at any position, for example, at the center
of the substrate 21, at a position near the center, or near any one of the bi-directional
microphone units 20, 25, 30. The orientation of the nondirectional microphone unit 10 is
arbitrary.
[0082]
Although bi-directional microphone unit 30 is located on the center point of substrate 21 in the
present embodiment, the position of bi-directional microphone unit 30 is not limited to this. The
position of the bi-directional microphone unit 30 may be disposed at any position as in the
nondirectional microphone unit 10 as long as it is disposed within the sound collecting area of
the other microphone units 10, 20, 25. .
[0083]
On the other hand, at least the diaphragms of the bidirectional microphone units 20 and 25 are
disposed on the same plane from the viewpoint of matching the phases of the output signals
among the microphone units 10, 20, 25 and 30 as much as possible. It is preferable to do.
[0084]
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In the present embodiment, an example has been described in which the microphone 1 is
suspended from a ceiling such as a concert hall so that the directional axis of the bidirectional
microphone unit 30 points downward, but the present invention is not limited thereto.
The microphone 1 may be installed such that the directional axis of the bidirectional microphone
unit 30 is directed upward, for example, by embedding it on a floor or a desktop depending on
the application of sound collection and the like. Besides, the microphone 1 can be installed at
various arbitrary angles, such as setting the directional axis of the bi-directional microphone unit
30 in an oblique direction or a lateral direction, depending on the application of sound collection.
[0085]
The microphone and the microphone device according to the present invention can be designed
and changed without departing from the technical concept described in the claims.
[0086]
Reference Signs List 1 microphone 21 substrate 10 omnidirectional microphone unit 20, 25
bidirectional microphone unit (first and second bidirectional microphone unit) 30 bidirectional
microphone unit (third bidirectional microphone unit) 40 signal amplification Circuit (third signal
processing unit) 45 non-inverted / inverted amplification circuit (first signal processing unit) 50
non-inverted / inverted amplification circuit (second signal processing unit) 55 signal
amplification circuit (fourth signal processing section) ) 70 synthesis circuit (signal synthesis
unit) A, B, C output terminal 80 level adjustment unit
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