JPH0879882A - Stereo microphone device - Google Patents

Abstract

PURPOSE: To provide a stereo microphone device in which a high frequency characteristic with respect to sensitivity is improved, a sound from the front of a microphone is easily collected and noise due to vibration of a microphone capsule is reduced. CONSTITUTION: The equipment is provided with a microphone cabinet MC, 1st ominidirectional left and right microphone capsules L1, R1 provided to the front in the microphone cabinet MC whose sound collection face is directed opposite to the front side of the microphone, 2nd ominidirectional left and right microphone capsules L2, R2 provided to a rear side in the microphone cabinet MC whose sound collection face is directed the front side of the microphone, a left adder adding sound signals from the 1st and 2nd left microphone capsules L1, L2 to obtain a left sound signal and a right adder adding sound signals from the 1st and 2nd right microphone capsules R1, R2 to obtain a right sound signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereo microphone device.

[0002]

2. Description of the Related Art A conventional example of a stereo microphone device will be described with reference to FIG. In FIG. 9, the black circled portion of the microphone capsule indicates the sound collecting surface side. The same applies to the other figures. Non-directional first and second center microphone capsules C1 and C2 whose sound collecting surfaces are close to and opposite to each other and which face the direction of 90 degrees with respect to the front of the microphone are provided in the front part of the microphone cabinet MC. With
Left and right omnidirectional microphone capsules L and R, which face each other in the direction of 90 degrees with respect to the front of the microphone, are provided in the rear portion of the microphone cabinet MC so as to be separated from each other.

Then, as shown in FIG. 10, the adder A adds the first center audio signal and the left audio signal from the first center microphone capsule C1 and the left microphone capsule L, respectively.
When 1 is added to obtain a new left audio signal Lout,
The second center audio signal and the right audio signal from the second center microphone capsule C1 and the right microphone capsule R, respectively, are added by the adder A2 to obtain a new right audio signal Rout.

In such a stereo microphone device,
The microphone capsules C1, C2, L and R are integrally fixed, and the vibration noises of the microphone capsules C1 and C2 and the vibration noises of the microphone capsules L and R are canceled by each other.

[0005]

In such a conventional stereo microphone device, the microphone capsules C1, C2,
Since the sound collecting surfaces of L and R are oriented in a direction of 90 degrees with respect to the front of the microphone, the sound coming from the front of the microphone cabinet wraps around from the side and enters the microphone cabinet. The frequency characteristics of 3 kHz to 15 kHz are deteriorated. Also, the microphone cabinet M
The left and right microphone capsules L and R in the rear part of the C are arranged in front of the first and second senna microphone capsules C1 and C1.
Since there is C2, it becomes difficult to collect sound from the front.

In view of the above point, the present invention intends to propose a stereo microphone device in which the frequency characteristic in the high frequency range of the sensitivity is good and the sound from the front of the microphone is easily collected.

Further, the present invention proposes a stereo microphone device in which the frequency characteristics in the high frequency range of sensitivity are improved, the sound from the front of the microphone can be easily collected, and the noise due to the vibration of the microphone capsule can be reduced. Is what you are trying to do.

[0008]

The first aspect of the present invention is directed to a microphone cabinet MC and an omnidirectional sound pickup surface provided in a front portion of the microphone cabinet MC, the sound collecting surface being directed in the opposite direction to the front surface of the microphone. The first left and right microphone capsules L1,
R1 and omnidirectional second left and right microphone capsules L2, R2, which are provided in the rear part of the microphone cabinet MC and whose sound collecting surface faces the same direction as the front of the microphone, and the first and second microphone capsules.
Of the left microphone capsules L1 and L2 to obtain a left audio signal Lout, and the audio signals from the first and second right microphone capsules R1 and R2 are added to the right A stereo microphone device having a right adder A2 for obtaining an audio signal Rout.

According to a second aspect of the present invention, in the stereo microphone device according to the first aspect of the present invention, the second left and right microphone capsules L2 and R2 are located outside the first left and right microphone capsules L1 and R1. It is a stereo microphone device characterized by the following.

A third aspect of the present invention is the stereo microphone device according to the first or second aspect of the present invention, in which the first and second left microphone capsules L1 and L2 are integrally fixed and the first and second left microphone capsules L1 and L2 are integrally fixed. Second right microphone capsule R1, R2
Is a stereo microphone device characterized by being integrally fixed.

In the stereo microphone device of the first, second or third aspect of the present invention, the stereo microphone device is attached to a video camera.

[0012]

According to the first aspect of the present invention, the microphone cabinet M
In the front part of C, the omnidirectional first left and right microphone capsules L1 and R1 whose sound collecting surface faces in the opposite direction to the front surface of the microphone.
Is provided, and the omnidirectional second left and right microphone capsules L2, R2 whose sound collecting surface faces the same direction as the front surface of the microphone are provided in the rear portion of the microphone cabinet MC. And
The respective audio signals from the first and second left microphone capsules L1 and L2 are added by the adder A1 to obtain the left audio signal Lout.
Is obtained, and the first and second right microphone capsules R1 and R2 are obtained.
The respective audio signals are added by the adder A2 to obtain the right audio signal Rout.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment shown in FIG. 1, the MMIC cabinet M
First left and right microphone capsules L1 and R1 whose sound collecting surfaces face in the opposite direction to the front surface of the microphone are provided in the front portion of C.
In the rear part of the microphone cabinet MC, the second left and right microphone capsules L whose sound collecting surface faces the same direction as the front surface of the microphone.
2 and R2 are provided. In this case, the first and second left capsules L1 and L2 are arranged such that their sound collecting surface sides face each other, and the first and second right capsules R1 and R2 are
The respective sound collecting surfaces are arranged so as to face each other. The distance between the microphone capsules L1 and L2 and the distance between R1 and R2, and the distance between the outer ends of the microphone capsules L1 and R1 and L2 and R2
The interval between them is about several mm to several dozen mm.

In the embodiment of FIG. 2, the microphone cabinet M
The second left and right microphone capsules L2 provided in the rear part of C,
R2 is the first provided on the front part of the microphone cabinet MC.
The left and right microphone capsules L1 and R1 are positioned so as to be displaced outward by about half of their respective widths.

In the embodiment of FIG. 3, the microphone cabinet M
The second left and right microphone capsules L2 provided in the rear part of C,
R2 is the first provided on the front part of the microphone cabinet MC.
The left and right microphone capsules L1 and R1 are positioned so as to be displaced outward by about their respective widths.

As in the embodiment shown in FIGS. 2 and 3, the second microphone capsules L2 and R2 provided at the rear portion of the microphone cabinet MC are the first microphone capsule L provided at the front portion.
1 and R2, the outer portion between the microphone capsules L1 and L2 of the microphone cabinet MC and the outer portion between the microphone capsules R1 and R2 are rounded toward the outside. As a result, the frequency characteristic can be reduced.

As shown in FIG. 4, in the first, second and third embodiments shown in FIGS. 1, 2 and 3, the respective audio signals from the first and second left microphone capsules L1 and L2 are added by the adder A1. Addition is performed to obtain the left audio signal Lout. The audio signals from the first and second right microphone capsules R1 and R2 are added to the adder A2.
To obtain the right audio signal Rout. The left and right audio signals Lout and Rout are supplied to various stereo processing circuits and processed as necessary.

In the embodiment shown in FIGS. 1, 2 and 3, the first and second left microphone capsules L1 and L2 are integrally fixed, and the first and second right microphone capsules R are provided.
1, R2 are integrally fixed. Further, the first and second left microphone capsules L1 and L2 and the first and second right microphone capsules R1 and R2 may be integrally fixed.

As a result, the vibration noises of the first and second left microphone capsules L1 and L2 are canceled and reduced. Vibration noises of the first and second right microphone capsules R1 and R2 are canceled and reduced.

FIGS. 5 and 6 are curve diagrams showing the frequency characteristics of the sensitivity of Examples 1 and 2 of FIGS. 1 and 2, respectively. The horizontal axis represents frequency (Hz) and the vertical axis represents sensitivity (dB). The graphs of FIG. 5 and FIG. 6 are
The midpoint between the first and second left microphone capsules L1 and L2, and the first and second right microphone capsules R1 and R2, respectively.
On a straight line (reference line) connecting the middle point between the first and second left microphone capsules L1 and L2, the first and second left microphone capsules L1 and L2 in the direction of 90 degrees with respect to the reference line. In front of and on the reference line, the first and second right microphone capsules R
The relative position between the sound source and the stereo microphone device is set so that the sound of a constant level from the sound source (for example, a speaker) from the 1 and R2 sides is directed to the stereo microphone device, and the sound at each relative position is set. Frequency 2
The sensitivity (dB) of the left audio signal Lout when varied between 0 Hz and 20,000 Hz is measured by a data recorder and is shown by curves L, C and R, respectively.

According to the sensitivity curve C in FIG. 5, the stereo microphone device of the first embodiment shown in FIG. 1 has a frequency of 3 kHz as compared with the stereo microphone device of the conventional example shown in FIG.
Approximately 4d sensitivity in front of microphone at z ~ 15kHz
It was found that the value can be increased by about B to 6 dB.
This is because the sound pickup surface of each microphone capsule faces the front side of the microphone or faces the side opposite to the microphone front, so that the sound coming straight from the front of the microphone is efficiently collected by each microphone capsule. .

According to the sensitivity curve C in FIG. 6, the stereo microphone device of the second embodiment shown in FIG. 2 has a frequency of 3 kHz compared with the stereo microphone device of the conventional example shown in FIG.
Approximately 5d sensitivity in front of the microphone at z ~ 15 kHz
It can be seen that it can be increased by about B to 7 dB. This is because the sound pickup surface of each microphone capsule faces the front side of the microphone or faces the opposite side of the microphone front, so that the sound coming straight from the front of the microphone is efficiently collected by each microphone capsule, and This is because the sound volume picked up by the microphone capsules L2, R2 behind the cabinet MC becomes large. Although the description of the characteristics in the case of the third embodiment is omitted, the characteristics similar to those of the second embodiment are exhibited.

FIG. 7 shows an embodiment in which the stereo microphone device 1 of Embodiment 1, 2 or 3 is attached to the upper surface of the casing of the VTR integrated video camera 3. in this case,
In the stereo microphone device 1, the front surface of the microphone is parallel to the optical axis in the same direction as the imaging lens, and the camera 3
The microphone capsules L1, R1, L2, R2 in the plan view are attached to the upper surface of the box of the camera 3 so as to be the same as in FIG. 1, FIG. 2 or FIG. Reference numeral 2 is a windshield net of the stereo microphone device 1.

FIG. 8 shows an embodiment in which the stereo microphone device 1 according to the first, second or third embodiment is attached to the arm of the VTR integrated video camera 3 with its entire shape being substantially cylindrical. Also in this case, in the stereo microphone device 1, the front surface of the microphone is parallel to the optical axis in the same direction as the imaging lens, and the arrangement of the microphone capsules L1, R1, L2, and R2 in the plan view of the camera 3 is as shown in FIG. , Is attached to the arm of the camera 3 in the same manner as in FIG. 2 or FIG. Reference numeral 2 is a windshield net of the stereo microphone device 1.

According to the first stereo microphone device of the embodiment, the microphone cabinet MC and the omnidirectional sound collecting surface provided in the front portion of the microphone cabinet MC are directed in the opposite direction to the front surface of the microphone. The first left and right microphone capsules L1 and R1 and the omnidirectional second left and right microphone capsules L2 and R, which are provided in the rear portion of the microphone cabinet MC and whose sound collecting surface faces the same direction as the front surface of the microphone.
2 and a left adder A1 for adding the audio signals from the first and second left microphone capsules L1 and L2 to obtain a left audio signal Lout, and first and second right microphone capsules R1 and R2
And a right adder A2 that obtains a right audio signal Rout by adding each audio signal from the microphone, the frequency characteristic of the high frequency range of the sensitivity is good, and the sound from the front of the microphone is easily collected. Can be obtained.

According to the second stereo microphone device of the embodiment, in the first stereo microphone device of the embodiment, the second left and right microphone capsules L2 and R2 are provided.
Are located outside the first left and right microphone capsules L1 and R1, so that the frequency characteristics in the high frequency range of sensitivity are further improved, and a stereo microphone device that easily collects sound from the front of the microphone is provided. Obtainable.

According to the third stereo microphone device of the embodiment, in the first or second stereo microphone device of the embodiment, the first and second left microphone capsules L are provided.
Since 1 and L2 are integrally fixed and the first and second right microphone capsules R1 and R2 are integrally fixed, in addition to the effect of the first or second stereo microphone device of the embodiment, , First and second left microphone capsule L
The vibrations of 1 and L2 are offset, and the vibrations of the first and second right microphone capsules R1 and R2 are offset, so that the microphone noise due to the vibration of the microphone capsule can be reduced.

[0028]

According to the first aspect of the present invention, the microphone cabinet and the first omnidirectional left and right sound collecting surface provided in the front portion of the microphone cabinet, the sound collecting surface facing in the opposite direction to the front surface of the microphone. The mic capsule, the omnidirectional second left and right mic capsules provided in the rear part of the mic cabinet with the sound collecting surface facing the same direction as the front of the mic, and the first and second left mic capsules. Since it has a left adder for adding each audio signal of 1 to obtain a left audio signal and a right adder for adding each audio signal from the first and second right microphone capsules to obtain a right audio signal, It is possible to obtain a stereo microphone device in which the frequency characteristics of the high frequency range are improved and the sound from the front of the microphone is easily collected.

According to the second aspect of the present invention, in the stereo microphone device of the first aspect of the present invention, the second left and right microphone capsules are located outside the first left and right microphone capsules. In addition to the effect of the present invention of No. 1, the frequency characteristic in the high frequency range of sensitivity is further improved.

According to the third aspect of the present invention, in the stereo microphone device according to the first or second aspect of the present invention, the first and second left microphone capsules are integrally fixed, and
Since the first and second right microphone capsules are integrally fixed, in addition to the effect of the first or second invention, noise due to vibration of the microphone capsule can be reduced.

[Brief description of drawings]

FIG. 1 is a layout diagram showing a first embodiment of the present invention.

FIG. 2 is a layout diagram showing a second embodiment of the present invention.

FIG. 3 is a layout diagram showing a third embodiment of the present invention.

FIG. 4 is a block diagram showing a circuit of an embodiment of the present invention.

FIG. 5 is a frequency characteristic curve diagram of sensitivity according to the first embodiment.

FIG. 6 is a frequency characteristic curve diagram of sensitivity according to the second embodiment.

FIG. 7 is a perspective view of an example in which the stereo microphone device of the example is attached to a video camera.

FIG. 8 is a perspective view of another embodiment in which the stereo microphone device of the embodiment is attached to a video camera.

FIG. 9 is a layout diagram showing a conventional example.

FIG. 10 is a block diagram showing a conventional circuit.

[Explanation of symbols]

 L1 1st left microphone L2 2nd left microphone R1 1st right microphone R2 2nd right microphone MC Microphone cabinet 1 Stereo microphone device 2 Windshield 3 Video camera (VTR integrated video camera)

Claims (4)

[Claims] 1. A microphone cabinet, a non-directional first left and right microphone capsule provided in a front portion of the microphone cabinet, the sound collecting surface facing in a direction opposite to a front surface of the microphone, and the inside of the microphone cabinet. The sound signals from the first and second left microphone capsules are added to the omnidirectional second left and right microphone capsules, which are provided in the rear part of the microphone and have the sound collecting surface facing the same direction as the front surface of the microphone. A stereo adder for obtaining a left audio signal and a right adder for adding the respective audio signals from the first and second right microphone capsules to obtain a right audio signal. . 2. The stereo microphone device according to claim 1, wherein the second left and right microphone capsules are located outside the first left and right microphone capsules. . 3. The stereo microphone device according to claim 1, wherein the first and second left microphone capsules are integrally fixed, and the first and second right microphone capsules are integrally formed. A stereo microphone device characterized by being fixed to. 4. The stereo microphone device according to claim 1, 2 or 3, wherein the stereo microphone device is attached to a video camera.