JPH08331679A - Microphone for transmission - Google Patents

Abstract

PURPOSE: To provide a microphone for transmission which is small-sized and light in weight, does not give unnatural feeling at the time of being mounted or in appearance is difficult to be affected by ambient noise in performance and has high quality in quality. CONSTITUTION: Within the body (housing 6) provided with an earphone-shaped earhole inserting body 1, at least two directional microphone units 3-1 and 3-2 arranged by being apart in the direction of a collecting voice axis and a subtracter performs subtractions between the mutual outputs of these microphone units are stored or these devices are added to this body. By storing the bone-conduction microphone unit 2 which is adhered to the earphone-shaped earhole inserting body 1 and is arranged within the body (gum cover 5) and adding the output of the bone-conduction microphone unit 2 and the output of the subtracter, a collected voice output voice is formed as a final output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microphone for transmission, which is not easily affected by ambient noise.
Therefore, the present invention relates to a microphone for transmitting which is capable of picking up clear voice and is compact and lightweight.

[0002]

2. Description of the Related Art A narrow directivity microphone is used for transmitting in a place with a large amount of ambient noise (hereinafter referred to as sound pickup because it means sound pickup by a microphone) and in a situation where adjacent sounds are easily mixed. A close-talking microphone, or a bone conduction microphone is used.

First, there are narrow-directional microphones based on some principles, but the main ones currently used are: (1) Line microphone: A slit-shaped opening is formed in the front of the microphone unit. By attaching the acoustic tube, the sound from the direction other than the sound pickup direction is attenuated by the interference of sound waves. (2) Array microphone: Arranging multiple microphone units so that the sounds to be picked up arrive in phase. , The outputs of sounds other than the sounds to be collected are attenuated by adding the arrived sounds, (3) Secondary sound pressure gradient type microphones: a plurality (for example, 2
Direct sound pressure gradient type directivity microphone units are arranged in the direction of the sound collection axis and are subtracted from each other, and the secondary sound pressure gradient type directivity is sharpened. There is one configured to get.

The next close-talking microphone has a structure in which a directional microphone is arranged close to the mouth of the speaker, and the output level of ambient noise is reduced due to the directivity of the microphone itself, and the microphone further approaches the mouth. By doing so, it is possible to clearly pick up the voice of the speaker by increasing the overall voice level and increasing the sensitivity in the low frequency range (hereinafter referred to as the proximity effect) caused by bringing the directional microphone closer to the point sound source. it can.

The last bone conduction microphone is one in which a vibration pickup is applied to the bone (a hard part of the face) to collect only the bone conduction sound without including the air conduction sound (the sound transmitted through the space). It is most effective for intercepting ambient noise, which is a sound guide, and collecting sound.

[0006]

Each of the above-mentioned microphones conventionally used for collecting the voice of the talker and making it less susceptible to the influence of ambient noise is not suitable as described below. There are many, and there is not enough.

First, in a narrow directivity microphone,
In order to narrow the directivity to the low frequency range with a line microphone or array microphone, the shape of the system becomes large, especially when the low frequency range, which is the main frequency component of ambient noise and adjacent sound, is narrowed. It cannot be used as a microphone for transmission, which is the object of the present invention, because it requires a size of 1 m or more. Further, the secondary sound pressure gradient type microphone can obtain narrow directivity even in a small range even with a small size, but in principle has a drawback that the sensitivity is largely reduced at a low frequency, so that it is flat in a low range. If a high frequency characteristic is to be obtained, the noise level will increase and the SN ratio will decrease.

On the other hand, the close-talking microphone was originally made as a transmission microphone, and as described above, the proximity effect is used to reduce the output level of ambient noise. However, it has a drawback that it changes depending on the distance from the speaker's mouth to the microphone, and the sound quality of the picked-up voice changes depending on the arrangement position of the microphone. Therefore, we usually attach a microphone to the headphones so that the distance from the mouth does not change, but if you do not bring it close to your mouth, the sound quality will be insufficient bass and the effect of making it less susceptible to noise will decrease. A slightly long metal pipe is extended from the headphone part and a microphone is attached to the tip. Therefore, the metal pipe and the microphone become large and become awkward, and the headphones for holding them are inevitably large. In addition, the close-talking microphone has a drawback in that pop noise due to breathing (noise called “pop” generated when the microphone hits the wind) is apt to occur due to the fact that the microphone is close to the mouth, and it is necessary to take measures against it. .

Further, as described in the prior art, the bone conduction microphone is the most effective in blocking ambient noise, but the sensitivity and frequency characteristics of the microphone in collecting bone conduction sound are as follows. Since it varies depending on the contact pressure between the hard part and the microphone unit and the change in the contact area, it is necessary to select a place and method that can obtain them relatively stably. It is also important that the microphone itself does not cause discomfort to the person who wears it, and that the wearing state does not cause discomfort when viewed from the surroundings. Therefore, a method of incorporating a bone conduction microphone unit in an earphone or an earphone-shaped case is generally adopted.

However, the biggest drawback of this type of microphone in which the bone conduction microphone unit is incorporated in an earphone or an earphone-shaped case (earpiece insertion body) is that bone conduction sound reaches the middle and high range by the time it reaches the earpiece insertion body. Are attenuated and the frequency characteristics are significantly different from the air-conducted sound picked up by a normal microphone, and the quality of sound is lower than that of a normal air-conducted microphone due to the lack of nasal sounds. Therefore, this bone conduction microphone is rarely used for broadcasting or the like that requires high quality sound.

In view of these circumstances, the present invention relates to the above-mentioned various conventional microphones, which are capable of collecting high-quality sound without being affected by ambient noise even if the ambient noise is large. To realize a microphone,
An object of the present invention is to provide a microphone for transmitting, which has a small size and a light weight, does not feel uncomfortable when mounted, is less affected by ambient noise in terms of performance, and has good sound quality.

[0012]

In order to achieve the above object, the microphone for transmission of the present invention is arranged in a housing provided with an earphone or an earphone-shaped ear canal insert, spaced apart in the sound collecting axis direction. It comprises at least two directional microphone units and a subtractor for performing subtraction between the outputs of these microphone units.

Further, the microphone for transmission according to the present invention further comprises, in the housing, a bone conduction microphone unit disposed in close contact with the earphone or earphone-shaped ear canal insert, an output of the microphone unit and the output. And an adder for performing addition with the output of the subtractor.

The microphone for transmission according to the present invention is a high-pass filter for attenuating a super low frequency component contained in the output of the bone conduction microphone unit between the bone conduction microphone unit and the adder. Is inserted.

Further, in the microphone for transmission according to the present invention, a portion where the bone conduction microphone unit is arranged is separated from the other portion of the casing by a cover.

Further, in the microphone for transmission according to the present invention, the cover is made of a rubber material or an elastic polymer resin.

Further, in the microphone for transmission according to the present invention, at least one of the subtractor, the adder, and the high-pass filter is housed in the housing instead of being housed in the housing. It is arranged in.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. First, as the name of the invention indicates, the microphone to which the present invention is directed is a microphone for transmission, and the microphone has a structure in which the speaker wears it like a conventional close-talking microphone. Is preferred.

In the present invention, the microphone itself is further reduced in size and weight, and the microphone of the present invention is inserted into an earphone or an earphone-shaped ear canal so that the microphone does not feel uncomfortable both when it is attached and when it is externally seen. A microphone that has a structure integrated with the body (hereinafter, also referred to as an ear microphone).

As described above, by using the earphone as the microphone, the position of the microphone is naturally far from the mouth as compared with the conventional close-talking microphone. Therefore, the effect of making it less susceptible to noise is also deteriorated accordingly. Therefore, in the microphone for transmission of the present invention, a method is adopted in which the sound pressure gradient is increased from the primary to the secondary to make the directivity sharper and the proximity effect also appears strongly. . Further, the sensitivity in the low frequency range is lowered by making the sound pressure gradient quadratic, but as described in the following specific examples, bone conduction that is built in the same or independent housing is arranged in the same. By synthesizing the outputs of the microphone units, the sensitivity in the low frequency range is compensated, and it becomes possible to realize almost the target frequency characteristic.

FIG. 1 shows a specific embodiment of a microphone for transmission (ear microphone) of the present invention in (a) rear view and (b) cross-sectional view, respectively. In FIG. 1, 1 is an earphone-shaped ear canal insert, 2 is a bone-conduction microphone unit, 3-1, 3-2 are directional microphone units spaced apart in the sound collecting direction, and 4 is a semiconductor chip or the like. A printed circuit board 5 to which electronic parts are attached is a cover made of a rubber material or a polymer resin having elasticity for covering a space where the bone conduction microphone unit is arranged (hereinafter, a typical material name is referred to as a rubber cover), Reference numeral 6 is a housing, and 7 is an output cable for taking out the sound output of the microphone for transmission.
In the present specification, the box bodies that are isolated from the external space, such as the rubber cover 5 and the housing 6, are collectively referred to as a housing.

In the above, the bone conduction microphone unit 2 and the two directional microphone units 3-1,
3-2 is used as the sound collecting means of the microphone for transmission of the present embodiment, the bone conduction microphone unit 2 is used.
Is closely attached to the earphone-shaped ear canal insert 1 as shown in the drawing, and mainly collects low-pitched sound. In addition, two directional microphone units 3-1 and 3-2
Are arranged apart from each other in the sound collection axis direction, and the sound collection output sound of one microphone unit (for example, 3-1) is subtracted from the sound collection output sound of the other microphone unit (for example, 3-2). While the directivity of each microphone unit (3-1 and 3-2) is a primary sound pressure gradient type, by combining these into one and making it a secondary sound pressure gradient type, ambient noise It has a sharper directivity so that it is less susceptible to the effects.

FIG. 2 shows two directional microphone units 3-1 and 3-2 which are spaced apart from the bone conduction microphone unit 2 in the sound collecting axis direction in the above-described ear microphone embodiment (FIG. 1). 2 is a block diagram showing the signal processing for each of the collected sound output voices, and as described above, the collected sound outputs of the microphone units 3-1 and 3-2 are used to make the sound pressure gradient quadratic. In the subtractor 8, the signals are subtracted from each other. By making the sound pressure gradient quadratic, the directivity becomes sharp, but the sensitivity in the low frequency range decreases.

The bone conduction microphone unit 2 is used in the embodiment shown in FIG. 1 with the intention of compensating for this sensitivity drop in the low frequency range. The bone conduction microphone unit 2 is covered with a rubber cover 5 so as not to come into contact with a portion other than the ear canal insert 1 such as the housing 6 and pick up vibrations from the portion. Therefore, it is preferable to configure the housing 6 and the rubber cover 5 as independent housings, but as another configuration, the rubber cover 5 is provided in the housing (in this case, the entire housing becomes one housing). Of these, the bone conduction microphone unit 2 may be arranged in close contact with the ear canal insert 1.

Further, since the output of the bone conduction microphone unit 2 is mainly composed of noise and contains an ultra-low frequency range component which is unsuitable for picked-up voice, the high-pass filter (HPF) 9 shown in FIG. After removing this through
The adder 10 adds the output of the subtracter 8 to form a collected output sound as the final output of this embodiment on the output side of the adder, and through the output cable 7 (FIG. 1), the housing (housing 6) Taken out.

The above is the configuration of the specific example of the microphone for transmitting according to the present invention. Here, the earphone-shaped ear canal insert 1 shown in FIG. 1 to the lowermost end of the housing 6 (the leftmost end in FIG. 1). ) May be small, and thus the microphone according to the present invention will be small and lightweight.

That is, the proximity effect usually becomes more remarkable as the directivity becomes sharper. Therefore, the secondary sound pressure gradient type has a stronger proximity effect than the primary sound pressure gradient type, and the effect of making the secondary sound pressure gradient type less susceptible to the ambient noise is greater. However, on the other hand, since a new problem that the sound quality changes due to the change in the distance from the mouth to the microphone occurs, the microphone according to the present invention takes the form of an ear microphone, and the distance from the mouth to the microphone seems to be almost constant and does not change. I have to. Further, in the microphone of the present invention, the distance from the mouth to the microphone is larger than that of the conventional close-talking microphone (2 to 3 times more than the close-talking microphone).
Sound quality changes less. Here, the size of the microphone for transmission shown in FIG. 1 is (a) as an example.
In the rear view, the length is about 70 mm and the width is about 15 mm (extremely small).

In the above-described example, the ear microphone is realized by using three microphone units (two directional microphone units and bone conduction microphone unit), but this is manufactured even if the performance is slightly deteriorated. For the purpose of keeping the price low, it is possible to use two microphone units (that is, only two directional microphone units) to produce a product having similar performance. In this case, the sound collection of the two directional microphone units formed in the secondary sound pressure gradient type is also made to play the role of sound collection by the bone conduction microphone unit, and the number of parts is small and the configuration is simple, but the sensitivity is low. However, it is unavoidable that it is inferior to the one using three microphone units due to variations in the performance of each product and the degree of being less susceptible to the influence of directivity and ambient noise.

Further, in the above-mentioned example, the microphone for transmission according to the present invention is constructed integrally with the earphone-shaped ear canal insert, but instead of the earphone-shaped ear canal insert, a conventional one having an original sound receiving function is used. By using the earphone of, it is possible to provide a bidirectional function as in the case of a conventional close-talking microphone. However, in this case, by configuring the transmitter with the microphone for transmission of the present invention,
The degree to which the intelligibility of the transmitted voice is improved with respect to ambient noise is no less than that of the conventional close-talking microphone. Needless to say, by incorporating an earphone in the microphone for transmission of the present invention, an input cable for supplying voice to the earphone is added in addition to the output cable 7 shown in FIG.

FIG. 3 shows the characteristics of the microphone for transmission according to the present invention, in particular, the output frequency characteristic (voltage) of the transmission voice, and 90 ° and 1 for a microphone that sounds similar to this.
The output frequency characteristic (voltage) for long-distance sound from the 80 ° direction, that is, ambient noise is shown. As can be seen in the figure, even when the loudness of the sound reaching the microphone is the same as the transmitted voice and the ambient noise, the ambient noise is smaller than the transmitted voice by about 25 dB or more in the output of the microphone. From this, it can be seen how the microphone for transmitting of the present invention is excellent in that it is hardly affected by ambient noise.

[0031]

As described above, according to the microphone for transmission of the present invention, at least two microphones are arranged in the housing provided with the earphone or the ear canal insert of the earphone type so as to be separated in the sound collecting axis direction. Since a directional microphone unit is housed and the outputs of these microphone units are subtracted from each other to realize a secondary sound pressure gradient type narrow directional microphone, the obtained microphone is a conventional close-talking microphone. It is a compact and lightweight microphone that does not feel uncomfortable to wear and has a good appearance, and is not easily affected by ambient noise.

Further, according to the microphone of the present invention, the low sensitivity in the low range due to the use of the secondary sound pressure gradient type narrow directional microphone is compensated by the sound collection by the bone conduction microphone arranged in the housing. By
Compared to the sound output of a single bone conduction microphone, which is a microphone that is not easily affected by ambient noise, the same purpose (making it less susceptible to ambient noise) in sound quality and SN ratio is achieved. It is possible to realize a microphone for transmission to achieve this.

As described above, the microphone for transmission of the present invention is not easily affected by ambient noise. Therefore, by using this microphone instead of the transmitter of the current telephone, hands-free (transmission in a noisy place) (You do not need to hold the handset)
It becomes possible to make a call. Further, in device control by voice input in a factory or the like, there is a problem of interference noise such as ambient noise and reverberation sound, but these problems are solved by using the microphone according to the present invention.

In television and radio broadcasting,
Conventionally, close-talking microphones have been mainly used for sound pickup in places with high ambient noise such as sports broadcasts and helicopters, but the television screen is not very smart. On the other hand, by using the transmission microphone of the present invention, it becomes possible to transmit a smarter image with a good screen image.

[Brief description of drawings]

FIG. 1 shows a specific example of a microphone for transmission according to the present invention.

FIG. 2 shows signal processing for each sound output sound of the bone conduction microphone unit and the two directional microphone units in the embodiment shown in FIG.

FIG. 3 shows the output frequency characteristic of the transmitted voice and the output frequency characteristic of the ambient noise of the microphone for transmission of the present invention.

[Explanation of symbols]

 1 Earphone-shaped ear canal insert 2 Bone conduction microphone unit 3-1, 3-2 Directional microphone unit 4 Printed circuit board 5 Rubber cover 6 Housing 7 Output cable 8 Subtractor 9 High-pass filter (HPF) 10 Adder

Claims (6)

[Claims] 1. A subtraction is performed between at least two directional microphone units and a microphone unit output, which are arranged in a housing provided with an earphone or an earphone-shaped ear canal insert, and are separated from each other in a sound collecting axis direction. A microphone for transmission that contains a subtractor. 2. The microphone for transmission according to claim 1, further comprising a bone conduction microphone unit disposed in the housing in close contact with the earphone or earphone-shaped ear canal insert body, and the microphone unit. A microphone for transmission, comprising an adder for adding the output and the output of the subtractor. 3. The microphone for transmission according to claim 2, wherein a high-frequency component included in the output of the bone-conduction microphone unit is attenuated between the bone-conduction microphone unit and the adder. A microphone for transmission with a bandpass filter inserted. 4. The microphone for transmission according to claim 2, wherein a portion where the bone conduction microphone unit is arranged is separated from another portion of the housing by a cover. 5. The microphone for transmission according to claim 4, wherein the cover is made of a rubber material or a polymer resin having elasticity. 6. The microphone for transmission according to claim 1, wherein at least one of the subtractor, the adder, and the high-pass filter is provided in the housing. A microphone for transmission which is arranged outside the housing instead of being housed.