JP3504135B2 - Microphone device - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microphone device effective for preventing howling and waterproofing, and more particularly to a microphone device effective for use in a megaphone.

2. Description of the Related Art In an electronic device in which a speaker and a microphone are integrally assembled, the microphone is attached via a cushioning material or the like so that vibration of the device body is not input as noise or howling. However, in the case of an electronic device in which the speaker is integrally attached to the device body, air vibration from the speaker goes around the external space and is input to the microphone, or the vibration of the device body due to the speaker is input to the microphone. So-called howling may occur due to the combination of the input acoustic vibration and the output acoustic vibration. In particular, when the electronic device is a waterproof device, since the inside of the electronic device has a substantially sealed structure, a change in internal air pressure due to the vibration of the speaker is input to the microphone, and howling is likely to occur. Further, since the speaker and the microphone are integrally assembled, the howling may occur because the vibration of the main body of the device is input directly or into the microphone as air vibration inside the device. As a means for solving such a problem, it is known to use a unidirectional microphone that utilizes the phase difference of air vibrations due to the difference in the transmission distance from the sound source that is applied before and after the diaphragm of the microphone. In addition, a close-talking microphone is known in which two microphones are used, the inputs of the respective microphones are applied in opposite phases to the amplifier, and noise and howling are reduced by the time difference of air vibrations transmitted by the distance difference from the sound source. There is.

As described above, in the conventional electronic equipment which uses the unidirectional microphone, the waterproof structure and the acoustic structure are simultaneously provided in order to make the unidirectional microphone waterproof. It had to be configured, and the structure of the equipment was complicated and large, so it could not be used. If the close-talking microphone using two microphones is waterproof, it is necessary to apply a waterproof structure to each microphone, and the distance between the two microphones cannot be reduced. The acoustic phase difference and the acoustic phase difference outside the equipment were different, and sufficient performance was not obtained. The present invention solves the above problems and provides a microphone device capable of simultaneously satisfying howling prevention and waterproofing.

The microphone device according to claim 1 of the present invention is a microphone device in which a first microphone for voice input and a second microphone for preventing howling are arranged adjacent to the main body of the device. The first microphone has a structure in which external air vibration is input to the diaphragm, and the second microphone has a structure in which the diaphragm is shielded from external air vibration.
According to the invention of claim 1, since the second microphone for preventing howling has a structure in which the diaphragm is shielded from external air vibration, it may be built in the device body.
Therefore, the waterproof structure can be eliminated. The microphone device according to claim 2 of the present invention is a microphone device of a megaphone, wherein a speaker is provided in a front portion of the megaphone, and a first microphone and a second microphone are arranged in a rear portion side by side on an inner wall of the megaphone body. The front of the first microphone is open and the front of the second microphone is closed. According to the second aspect of the invention, since the front side of the second microphone is sealed, it can be attached inside the megaphone body, and the waterproof structure can be eliminated.

BEST MODE FOR CARRYING OUT THE INVENTION A microphone device of the present invention is a microphone device in which a first microphone for voice input and a second microphone for preventing howling are arranged adjacent to a device body, and the first microphone is a diaphragm. The structure is such that external air vibrations are input. On the other hand, the second microphone has a structure in which the diaphragm is shielded from external air vibrations. As described above, in the microphone device of the present invention, a close-talking microphone can be configured by disposing the first microphone and the second microphone adjacent to the device body, and the air pressure inside the device due to the vibration of the speaker can be increased. The change and the vibration of the device itself are directly or become air vibrations inside the device and are simultaneously input to the first and second microphones, which are input to the amplifier in opposite phases to cancel each other out. It can prevent and reduce noise. The first microphone has a structure to which external air vibrations are input, while the second microphone has a structure to block external air vibrations. Therefore, by making the megaphone body a waterproof structure, It can be installed and stored inside the device body without requiring a waterproof structure.
Therefore, only the first microphone needs to have a waterproof structure, and the waterproof structure of the microphone device can be facilitated. (Embodiment 1) The megaphone of the present invention is configured by combining a horn mouth 1, a megaphone body 2 and a handle 3 as shown in FIG. 1, and a battery case 4 is provided at a rear portion of the megaphone body 2. As shown in FIG. 2, the horn mouth 1 has a ring-shaped permanent magnet 11 and a yoke 1 inside.
2. A magnetic circuit composed of a plate 13 and a yoke 1
The voice coil is inserted into the magnetic gap formed between the plate 2 and the plate 13. The upper end of the voice coil is coupled to the dome-shaped diaphragm 14, and the voice signal input to the voice coil acts together with the magnetic circuit to be converted into vibration of the diaphragm 14. An equalizer 15 and a throat 16 are provided in front of the diaphragm, and reflectors 17 and 18 are attached to an opening portion of the throat 16 so that sound is emitted from a tip opening portion of the horn mouse 1. The reflector 18 is fixed to the horn mouse 1 with a screw 19, and the horn mouse 1 and the megaphone body 2 are joined by tightening the screw 19 into the boss 20 of the megaphone body 2. When connecting the horn mouse and the megaphone body, as shown in FIG. 4, the throat packing 6 is fitted inside the horn mouse, and is attached via the waterproof packing 7 made of rubber and flexible resin to the outside, and the horn mouse 1 and the megaphone are attached. The gap between the body 2 is filled so that the space between the horn mouth 1 and the megaphone body 2 is airtight and waterproof. As shown in FIG. 4, a microphone unit 21 is arranged in the upper rear part inside the megaphone body 2. The microphone unit 21 is the main microphone 2 serving as the first microphone.
2 and a sub microphone 23 serving as a second microphone. The main microphone and the sub microphone are housed in the microphone retainer 24 via thin films 22a and 23a made of, for example, rubber having a cushioning function and a waterproof function, and a rib 25 at the rear of the megaphone body. Install it by inserting it into. Main microphone 2
2 has a small opening 26 formed in the front of the megaphone body to input external sound. The main microphone 22 is covered with a thin film 22a made of rubber or the like to obtain a waterproof effect, but an opening 22b is formed corresponding to the opening 26, and sound is sufficiently input. Furthermore, since a thin film such as rubber has a buffering effect, it prevents vibration of the megaphone body, for example, noise such as contact noise when operating the megaphone and noise of rubbing against clothes, and it has a high S / N input signal. Can be obtained. The sub microphone 23 is used for preventing howling of the megaphone. Therefore, an opening is not formed in the megaphone body in front of the sub microphone, and external sound is not input. For this reason, there is no opening in front of the sub microphone, water from the outside is not directly applied to the sub microphone, and waterproofing is completely performed. The megaphone is a sound vibration that the sound from the megaphone body circulates around the outside of the megaphone and inputs to the microphone, and a sound pressure that the back pressure of the diaphragm propagates through the thin space inside the megaphone and inputs to the microphone. Howling is caused by the vibration of its own mechanical vibration input to the microphone. Among them, the sub microphone receives the vibration input by the back pressure of the diaphragm through the thin gap inside the megaphone and the vibration input by the megaphone itself into the microphone in phase with the main microphone,
Howling is prevented by converting this into an electric signal and inputting it in a phase opposite to that of the electric signal from the main microphone for mixing. Thus, since the sub microphone 23 is simply attached to the inner wall of the megaphone body, the main microphone 22 and the sub microphone 23 can be arranged extremely close to each other. A printed wiring board 28 on which a circuit 27 made up of electrical parts such as LSI, IC, resistors, capacitors, etc. which constitute a 10 W class amplifier is mounted on the upper rear part of the megaphone body.
Attach. The printed wiring board 28 is attached so as to be sandwiched between the rib on the rear of the megaphone body and the board retainer 29. The substrate retainer 29 is provided with a positive side connection terminal 30 and a negative side connection terminal 31 made of a conductive and springy material, for example, a phosphor bronze plate, and is screwed to the battery case housing rear wall 35b. At the bottom of the megaphone body, a power switch attached to the handle and a hole 32 through which a connecting wire for connecting to the volume are inserted are formed and a rubber bush is fitted therein. A battery case accommodating portion 35 is formed at the center of the megaphone body 2 in the axial direction of the megaphone. The battery case storage portion 35 is continuously formed integrally with the megaphone body, and has a battery storage side wall 35a and a battery storage rear wall 35b.
Consists of. A small opening is formed in the battery rear wall 35b, and the tips of the positive side connecting terminal 30 and the negative side connecting terminal 31 are projected from the opening. The plus-side connection terminal 30 is arranged in the center of the battery case housing, and the minus-side connection terminal 31 is arranged in parallel apart from the center position. A female screw 36 is formed in the front opening portion of the battery housing portion 35 to form one of the fitting structures. The battery case 4 is, as shown in FIG. 5, a lid 4 that serves as a lid for the battery housing portion 35.
1 has a male screw 42 in the peripheral portion thereof and is fitted with a female screw 36 formed in the opening portion of the battery case storage portion. The battery case 4 is housed in the battery case housing portion, and the female screw 36 and the male screw 42 are fitted to each other to seal the opening of the battery case housing portion 35 and to make the megaphone waterproof. As shown in A view, a finger hole 41a divided into three directions from the center is formed on the surface side of the lid. The battery case is composed of a lid 41, a battery case upper portion 43, and a battery case lower portion 44. The battery case upper portion 43 is composed of a central tubular portion 43a and a battery terminal portion 43b formed at one end of the central tubular portion. The battery terminal portion 43b is provided with one battery terminal.
The lid 41 and the battery case top 43 are integrally assembled with six screws 43c. The screw 43c is assembled by inserting a driver into the driver hole 44c formed in the lower battery case 44 and tightening the screw 43c.
Since the driver hole 44c is formed in the lower battery case 44, the screw 43c can be easily tightened or removed even if the screw 43c is inside the radius of the lower battery case 44. The battery case bottom 44 is provided with a battery storage wall 44a having a length of about 1/5 of the battery length for preventing the battery from falling when storing the battery.
As shown in F view, the other end of the central tubular portion 43a is screwed with six screws 49, and the other battery terminal is provided. The battery terminal plate 45 is made of a highly conductive metal material, and is twisted at a midpoint to connect the positive electrode of one battery to the negative electrode of the next battery, and is arranged so as to pass through the hollow of the central cylindrical portion 43a. To be done. Battery terminal board 45
One of them is fixed by being wound around the battery terminal portion 43b, and the other is fixed by being sandwiched between the central cylindrical portion 43a and the central protruding portion 44b of the lower battery case 44, and its tip is in contact with the negative electrode of the battery. It is bent to form a battery terminal. When the battery terminal plate 45 connects the plus and minus electrodes of the adjacent batteries, all six batteries inserted in the battery case are inserted in the same direction and connected in series. The negative terminal connected in series has a cord hole 44d
A lead wire (not shown) is connected to the ring-shaped power supply terminal 46 made of a metal material by soldering. The battery terminal plate 45 with one terminal tooth on the plus side is extended to near the center through a part of the central protrusion 44b, and the terminal screw 4
Connect to 8. The power supply terminal 45 and the terminal screw 48 are insulated by inserting a ring-shaped insulating bush 47 therebetween. The terminal screw 48 is press-fitted and fixed in the lower battery case 44. Therefore, as shown in F view, the power supply terminal 46 and the terminal screw 48 are concentrically arranged with a distance equal to the distance between the positive side connection terminal 30 and the negative side connection terminal 31. As shown in FIG. 6, a drawbar 51 is attached to the front of the handle 3. The power switch is composed of the micro switch 52, and the rib 5 on the VRSW case 53
It is attached so that it fits into 3s. The volume 54 is attached by a VR nut 55 so as to sandwich the VRSW case upper portion 53. After attaching the micro switch and volume in this way, the rubber cover 5
It is screwed to the step portion of the handle together with the VRSW lower case 57 with 6 in between. A knob 58 is attached to the shaft of the volume, and a part of the periphery of the knob is projected from a hole at the rear of the handle so that the knob can be operated. Draw 51
Is attached to the handle 3, the micro switch 52 and the volume 54 are attached to the VRSW case 53, and the knob 58 is attached.
After attaching, part of the knob 58 is made to protrude from the hole at the rear of the handle, and the rubber cover 56 and VRSW case bottom 57 are attached.
Along with that, it is screwed to the step of the handle, but V
Of the four screw holes 53a to 53d on the RSW case 53, the two screw holes 53c and 53d are inside the radius of the knob 58, so that the knob 58 is notched or partially at the position corresponding to the screw hole. A hole (not shown) is formed, and a screwdriver is inserted into this notch and screwed. The wiring of the micro switch and the volume is connected to the circuit 27 through the hole 32 of the megaphone body. As shown in FIG. 3, slide grooves 59 are formed on both upper sides of the handle, and a projection 33 (shown on the upper right side in FIG. 4) formed in the lower portion of the megaphone body 2 is fitted into the slide grooves 59,
Slide the handle to the rear of the megaphone body to integrate the megaphone body with the handle. After that, the horn mouse 1 is fixed to the front of the megaphone body with screws 19 to prevent the handle from coming off, and at the same time, the whole body is integrated and the inside of the megaphone body is assembled into a waterproof structure. Since the megaphone of the present invention is constructed as described above, when replacing the battery, first the lid 41 is used.
Put the thumb, forefinger, and middle finger into the three finger holes 41a, and rotate the battery case 4 to remove the battery case 4 from the megaphone body 2. Then, the old batteries are removed, and six new batteries 60 are inserted side by side in the same direction around the battery case. Next, the battery case 4 is inserted into the battery case storage portion 35 of the megaphone, a finger is put in the finger hole, and the battery case is rotated, so that the male screw and the female screw are fitted to each other for replacement. As a result, the terminal screw 48 to which the positive side battery terminal of the battery case is connected and the power source terminal 46 to which the negative side battery terminal is connected are protruded from the opening of the battery housing rear wall of the battery case housing portion 35. 30 and the negative side connection terminal 31 are brought into contact with each other. As shown in FIG. 7, the electric circuit of the megaphone of the present invention includes a microphone circuit 110, a microphone amplifier 111, a preamplifier 112, a main amplifier 113, a whistle oscillator circuit 115, and a megaphone power control circuit 11.
6, a whistle power supply control circuit 117, a battery and a switch circuit 118. The microphone circuit 110 is configured by connecting the main microphone 22 and the sub microphone 23 shown in FIG. 4 so as to input to the microphone amplifier 111 in opposite phases. That is, the main microphone 22 is connected to the variable resistor 121 by connecting the resistor 22e to the power line side. The sub microphone 23 is connected to the variable resistor 121 by connecting the resistor 23e to the ground side. Therefore, the main microphone 22 and the sub microphone 23
Signals input in phase with each other cancel each other out, and only the difference signal between the main and sub microphones is amplified. In-phase signals include vibration input by the back pressure of the diaphragm through a narrow gap inside the megaphone and vibration of the megaphone itself.These signals are input to the microphone amplifier in the opposite phase and mixed to cancel out. Ai, eliminate noise and prevent howling. (Embodiment 2) In this embodiment, a step is formed at the rear of the megaphone body as shown in FIG.
And the sub microphone 23 are attached in different steps. The main microphone is a thin film 2 made of rubber or the like that has a cushioning function and a waterproof function.
The entire circumference is covered with 2a, stored in the microphone holder 24s from the rear of the main microphone, and fitted into the rib 25s of the megaphone body to be attached. The thin film has an opening 22b in front of the microphone.
The opening 2a is also formed in the megaphone body.
The sub microphone 23 is covered with a thin film 23a of rubber or the like having a cushioning effect and a waterproof effect, and is housed in a microphone retainer 24t from the rear of the main microphone and fitted into a rib 24t of a megaphone body. The thin film covered by the sub microphone does not have an opening in front of the microphone.
No opening is formed in the megaphone body. Other configurations are the same as those in the first embodiment.

As described above, according to the present invention, the second microphone for preventing howling has a structure in which the diaphragm is shielded from external air vibrations. Therefore, the second microphone may be built in the device body. The waterproof structure can be eliminated. Further, according to the present invention, since the front of the second microphone is hermetically sealed, it is possible to eliminate the waterproof structure of the second microphone simply by mounting the megaphone housing inside the housing. it can. Therefore, the first microphone and the second microphone can make the acoustic phase difference inside the device equal to the acoustic phase difference outside the device, and howling can be prevented and noise can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a megaphone equipped with a microphone device of the present invention.

FIG. 2 is a sectional view of the megaphone according to the embodiment of the present invention.

FIG. 3 shows a rear view of the megaphone.

FIG. 4 shows an exploded cross-sectional view of a horn mouse and a megaphone body.

FIG. 5 shows an exploded cross-sectional view of a battery case.

FIG. 6 shows an exploded sectional view of a handle portion.

FIG. 7 shows an electrical circuit diagram of the megaphone of the present invention.

FIG. 8 shows a sectional view of a microphone portion of a second embodiment according to the present invention.

[Explanation of symbols]

1 horn mouse 2 megaphone body 3 handles 4 battery case 21 microphone unit 22 Main microphone 23 sub microphone 36 female screw 41 Lid 59 slide groove

Claims (2)

(57) [Claims] 1. A microphone device in which a first microphone for voice input and a second microphone for preventing howling are arranged adjacent to a device body, wherein the first microphone is used.
The microphone device has a structure in which external air vibration is input to the diaphragm, and the second microphone has a structure in which the diaphragm is shielded from external air vibration. 2. A microphone device of a megaphone in which a speaker is provided in a front portion of the megaphone, and a first microphone and a second microphone are arranged side by side on an inner wall of the megaphone body in a rear portion of the megaphone. The front of the first microphone is open. The microphone device is characterized in that the front of the second microphone is sealed.