JPH08331679

Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH08331679
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
transmitting microphone, which is not particularly susceptible to ambient noise, and is therefore
able to pick up clear speech and is compact and lightweight It relates to a transmitting
microphone.
[0002]
2. Description of the Related Art Narrow directional microphones are used for voice transmission
in a location where ambient noise is large (in the following, referred to as sound collection to
mean sound collection by a microphone) or sound collection in a situation where adjacent sounds
are likely to be mixed. A close talk microphone or a bone conduction microphone is used.
[0003]
First, although there are narrow directional microphones based on several principles, the main
ones currently used are: (1) Line microphone: an acoustic tube having a slit-like opening in front
of the microphone unit Attenuates sound from directions other than the target direction of sound
collection by interference of sound waves, (2) Array microphone: Arranges plural microphone
units so that sounds to be collected arrive in phase and reach them Attenuated sounds are added
to attenuate the output of sounds other than the sound to be collected. (3) Secondary sound
pressure gradient microphone: Multiple (for example, two) primary sound pressure gradient
directivity Microphone units are arranged separately in the sound collection axis direction, and
sharp directivity of secondary sound pressure gradient is obtained by performing subtraction
between sound collection outputs of these microphone units. There is a thing, which is
03-05-2019
1
configured as.
[0004]
The next close talk microphone has a structure in which a directional microphone is placed close
to the mouth of the talker, and the directivity of the microphone itself reduces the output level of
the ambient noise, and further brings it close to the mouth. It is possible to clearly pick up the
voice of the transmitter by increasing the overall sound level and increasing the sensitivity of the
low frequency range (hereinafter referred to as proximity effect) caused by bringing the
directional microphone closer to the point sound source.
[0005]
The last bone conduction microphone is the one that applies the vibration pickup to the bone
(hard part of the face) and picks up only the bone conduction sound without including the air
conduction sound (sound transmitted through the space). It is most effective in intercepting and
collecting certain ambient noise.
[0006]
The above-mentioned respective microphones conventionally used to pick up the voice of the
transmitter and to be less susceptible to ambient noise are not suitable as described below. There
are many, yet not enough.
[0007]
First of all, in a narrow directional microphone, in order to make the low directivity down to the
low frequency range by a line microphone or an array microphone, the shape as a system
becomes large, especially the low frequency range which is the main frequency component of
ambient noise and adjacent sound. In the case of narrow directivity including the above, it can
not be used as a transmitting microphone intended by the present invention because the size of 1
m or more is required.
In addition, secondary sound pressure gradient microphones can achieve narrow directivity even
in the low frequency range with small dimensions, but have the disadvantage that the sensitivity
drops significantly at low frequencies in principle, and they are flat in the low frequency range. In
order to obtain a proper frequency characteristic, the noise level increases and the SN ratio
decreases.
03-05-2019
2
[0008]
On the other hand, close-talking microphones were originally made as transmission microphones,
and as described above, use the proximity effect to reduce the output level of ambient noise, but
this proximity effect It varies with the distance from the mouth of the person to the microphone,
and has the disadvantage that the sound quality of the collected voice changes with the
arrangement position of the microphone.
Therefore, a microphone is usually attached to the headphones so that the distance from the
mouth does not change. However, the sound quality of the low-pitched sound becomes poor if it
is not made to approach the mouth. A slightly long metal pipe is extended from the headphone
part, and a microphone is attached to the tip of the metal pipe.
Therefore, the metal pipe and the microphone become large and somewhat disappointing, and
the headphones holding the same are inevitably large.
In addition, close-talking microphones are prone to pop noise due to breath when the
microphones are brought close to the mouth ("Pos" noise generated by the wind hitting the
microphones), and they also have the disadvantage of requiring measures for this .
[0009]
Also, although the bone conduction microphone is most effective in blocking ambient noise as
described in the prior art, the sensitivity and frequency characteristics of the microphone in bone
conduction sound collection are that with the hard part of the face Since it changes with the
contact pressure with a microphone unit, and the change of a contact area, it becomes necessary
to select the place and method from which they can be obtained comparatively stably.
In addition, it is also important that the microphone itself is not uncomfortable for the person
wearing it and that the wearing condition is not uncomfortable when viewed from the
surroundings. Therefore, generally, a method is adopted in which the bone conduction
microphone unit is incorporated in an earphone or earphone-shaped case.
03-05-2019
3
[0010]
However, the main drawback of this type of microphone in which the bone conduction
microphone unit is incorporated in an earphone or earphone-shaped case (ear-hole insert) is that
the bone-conduction sound attenuates its mid-high range until it reaches the ear-hole insert. That
is, the frequency characteristics are significantly different compared to the air conduction sound
picked up by the ordinary microphone, and the quality is lower in sound quality than the
ordinary air conduction sound microphone due to the lack of the nasal noise. Therefore, this
bone conduction microphone is seldom used for broadcasting or the like which requires high
quality voice.
[0011]
In view of these circumstances, the present invention realizes transmitting microphones capable
of high-quality sound collection with respect to the various microphones of the prior art
described above, even if the ambient noise is high. It is an object of the present invention to
provide a transmitting microphone which is small in size, light in weight, incongruent at the time
of wearing, and hardly affected by ambient noise in terms of performance and good in sound
quality.
[0012]
SUMMARY OF THE INVENTION In order to achieve the above object, the transmitting
microphone according to the present invention is disposed at a distance in the sound collecting
axis direction in a housing provided with an earphone or an ear-hole insert of the earphone type.
It accommodates at least two directional microphone units and a subtractor for performing
subtraction between these microphone unit outputs.
[0013]
Further, according to the present invention, the transmitting microphone further comprises a
bone conduction microphone unit disposed in close contact with the earphone or the ear-hole
insert of the earphone shape in the housing, an output of the microphone unit and the subtractor.
And an adder for performing addition with the output.
[0014]
Further, according to the transmission microphone of the present invention, a high pass filter is
03-05-2019
4
interposed between the bone conduction microphone unit and the adder for attenuating the ultra
bass component included in the output of the bone conduction microphone unit. It will be done.
[0015]
Further, in the microphone for transmitting speech according to the present invention, the
portion where the bone conduction microphone unit is disposed is separated from the other
portion of the housing by a cover.
[0016]
In the microphone for transmitting speech according to the present invention, the cover is made
of a rubber material or a polymer resin having elasticity.
[0017]
Further, in the microphone according to the present invention, at least one of the subtractor, the
adder, and the high pass filter is disposed outside the casing, instead of all of them being
accommodated in the casing. It is
[0018]
The invention will now be described in detail by way of example with reference to the
accompanying drawings in which: FIG.
First, the microphone targeted by the present invention is, as the title of the invention indicates, a
microphone for transmitting speech, and the microphone is constructed so that the speaker
wears it like a conventional close-talking microphone. Is preferred.
[0019]
In the present invention, in order to further reduce the size and weight of the microphone itself
and to prevent the user from feeling uncomfortable when wearing or wearing the microphone
itself, the microphone of the present invention is integrated with the earphone or earphone type
earhole insert The microphone of the structure (hereinafter, also referred to as an ear
microphone).
03-05-2019
5
[0020]
Thus, by making the microphone into an ear microphone, the position of the microphone
naturally becomes far from the mouth compared to a conventional close talk microphone.
Therefore, the effect of making noise less susceptible is also deteriorated accordingly, and in the
transmitting microphone according to the present invention, the sound pressure gradient is
increased from the first to the second, the directivity is sharpened, and the proximity effect is
strongly displayed. .
Also, although the sound pressure gradient lowers the sensitivity of the low range by making the
sound pressure gradient quadratic, as described in the following specific embodiments, the bone
conduction incorporated and arranged in the same or independent housing. By combining the
outputs of the microphone units, the sensitivity of the bass region is compensated, and it is
possible to realize almost the target frequency characteristics.
[0021]
FIG. 1 shows a specific embodiment of the transmitting microphone (ear microphone) of the
present invention in (a) rear view and (b) cross sectional view, respectively.
In FIG. 1, 1 is an earphone-shaped earhole insert, 2 is a bone conduction microphone unit, 3-1
and 3-2 are directional microphone units arranged separately in the sound collecting direction,
and 4 is a semiconductor chip etc. A printed circuit board to which electronic components are
attached, a cover 5 made of a rubber material or an elastic polymer resin covering a space where
a bone conduction microphone unit is disposed (hereinafter referred to as a rubber cover with a
typical material name) Reference numeral 6 is a housing, and 7 is an output cable for extracting
the sound output of the transmitting microphone.
In the present specification, boxes separated from the external space, such as the rubber cover 5
and the housing 6, are collectively referred to as a housing.
[0022]
03-05-2019
6
In the above, the bone conduction microphone unit 2 and the two directional microphone units
3-1 and 3-2 are used as the sound collection means of the transmitting microphone of this
embodiment, but the bone conduction microphone unit 2 is As shown in the drawing, it is closely
attached to the earphone type ear canal insertion body 1 and mainly picks up sound in the low
frequency range.
Further, the two directional microphone units 3-1 and 3-2 are disposed apart from each other in
the sound collecting axis direction, and one microphone unit (for example, 3-1) collects sound
output sound of the other microphone to the other microphone While subtracting the collected
sound output sound of the unit (eg 3-2), the directivity of the individual microphone units (3-1
and 3-2) is originally in the primary sound pressure gradient form, whereas these are one by one
In the secondary sound pressure gradient form, the directivity is further sharpened so as to exert
an excellent effect in that it is less susceptible to ambient noise.
[0023]
FIG. 2 shows the respective configurations of the bone conduction microphone unit 2 and the
two directional microphone units 3-1 and 3-2 disposed apart from each other in the sound
collecting axis direction according to the above-described embodiment of the ear microphone
(FIG. 1). Signal processing for sound output sound is shown in a block diagram, and as described
above, each sound output of the microphone units 3-1 and 3-2 is a subtractor 8 in order to make
the sound pressure gradient secondary. Are subtracted between the signals at.
The directivity is sharpened by making the sound pressure gradient quadratic, but the sensitivity
of the bass region is lowered.
[0024]
The bone conduction microphone unit 2 is used in the embodiment shown in FIG.
The bone conduction microphone unit 2 is covered by a rubber cover 5 so as not to contact with
parts other than the earphone type ear canal insert 1, for example, the housing 6, etc. to pick up
03-05-2019
7
vibration from that part. Therefore, the housing 6 and the rubber cover 5 are preferably
configured 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). Among them, the bone
conduction microphone unit 2 may be disposed in close contact with the ear canal insertion body
1.
[0025]
In addition, since the output of the bone conduction microphone unit 2 mainly includes noise and
an inappropriate super-bass component is included as the collected voice, the high-pass filter
(HPF) 9 shown in FIG. Are added to the output of the subtracter 8 in the adder 10, and the
collected sound output voice as the final output of the present embodiment is formed on the
output side of the adder, and is passed through the output cable 7 (FIG. 1) It is taken out of a
housing (housing 6).
[0026]
The above is the configuration in a specific embodiment of the microphone for transmitting
speech according to the present invention, but here, from the earlobe insert 1 of the earphone
type shown in FIG. 1 to the lowermost end (the left end in FIG. 1) of the housing 6 The length
may be small, and therefore, the compactness and lightness of the microphone according to the
present invention will be described.
[0027]
That is, the proximity effect usually becomes more pronounced as the directivity becomes
sharper.
Therefore, the proximity effect appears more strongly in the secondary sound pressure gradient
type than in the primary sound pressure gradient type, and the effect of making it less
susceptible to ambient noise also becomes greater.
However, on the other hand, since the sound quality changes due to fluctuations in the distance
from the mouth to the microphone, 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
substantially constant 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
03-05-2019
8
microphone (the distance from the close-talk microphone is 2 to 3 times), and the change in
sound quality is reduced. Here, the size of the transmitting microphone shown in FIG. 1 is, for
example, about 70 mm in length and about 15 mm in width (very small size) in the rear view of
(a).
[0028]
In the above example, three microphone units (two directional microphone units and a bone
conduction microphone unit) are used to realize the ear microphone, but this lowers the
manufacturing cost even if the performance is slightly reduced. For the purpose of suppressing, it
is also possible to use two microphone units (ie, with only two directional microphone units) to
produce a product having similar performance. In this case, the sound pickup of the two
directional microphone units formed in the secondary sound pressure gradient type also has a
role of sound collection by the bone conduction microphone unit, and the number of parts is
small and the configuration is simplified, but the sensitivity is It is inevitable that the directivity,
the degree of making it less susceptible to ambient noise, and the variation in performance of
each product are inferior to those using three microphone units.
[0029]
Further, in the above-described example, the transmitting microphone according to the present
invention is integrally formed with the earphone-shaped earhole insert, but instead of the
earphone-shaped earhole insert, a conventional earphone having a sound receiving function in
nature By using it, it is possible to provide the function of both transmission and reception like
the conventional close talk microphone. However, in this case, by configuring the transmitter
with the transmitting microphone of the present invention, the degree to which the clarity of the
voice to be transmitted is improved relative to the ambient noise is not inferior to the
conventional close-talking microphone. Needless to say, by incorporating the earphone in the
transmitting microphone of the present invention, an input cable for supplying sound to the
earphone is added in addition to the output cable 7 shown in FIG.
[0030]
FIG. 3 shows the characteristics of the transmitting microphone according to the present
invention, in particular, the output frequency characteristics (voltage) of the transmitting voice
03-05-2019
9
and the far-distance sound from the directions of 90 ° and 180 ° with respect to the
microphone that can be heard equally The output frequency characteristic (voltage) to noise is
shown. As can be seen in the figure, even if the sound reaching the microphone is the same as
the transmitted voice and the ambient noise, the ambient noise at the output of the microphone
is about 25 dB smaller than that of the transmitted voice. From this, it can be seen how excellent
the transmitting microphone according to the present invention is insusceptible to ambient noise.
[0031]
As described above, according to the microphone for transmitting speech of the present
invention, at least two microphones arranged at intervals in the sound collecting axis direction
are provided in the housing provided with the earphone or the ear-hole insert of the earphone
type. Is realized by incorporating a directional microphone unit of the second embodiment and
performing subtraction between the outputs of the microphone units to obtain a narrow
directional microphone of the secondary sound pressure gradient type, so that the obtained
microphone is a conventional close-talking microphone. It is smaller and lighter, has no sense of
discomfort when worn, and has a good appearance image, making it a transmitting microphone
that is less susceptible to ambient noise.
[0032]
Further, according to the microphone of the present invention, it is possible to compensate for
the decrease in sensitivity of the bass region due to the narrow directional microphone of the
secondary sound pressure gradient type by the sound collection by the bone conduction
microphone disposed in the housing. With the same purpose of dramatically improved sound
quality and S / N ratio as compared to the sound output output sound of a single bone
conduction microphone as a microphone that is less susceptible to ambient noise, Can be realized
as a transmitting microphone for achieving.
[0033]
Thus, since the transmitting microphone according to the present invention is not susceptible to
ambient noise, using it in place of the transmitter of the current telephone enables hand-free
operation in a noisy place (handset the handset You do not have to hold the
Further, in the device control by voice input in a factory or the like, there is a problem of jumping
in disturbance noise such as ambient noise and reverberation, but these problems are solved by
03-05-2019
10
using the microphone according to the present invention.
[0034]
Also, in television and radio broadcasting, close-talking microphones have been mainly used in
the past to collect sound in places with high ambient noise such as sports broadcasts and
helicopters, but the screen shot of television is not very smart. .
On the other hand, by using the microphone for transmitting speech according to the present
invention, it is possible to transmit a smarter image with better image quality.
[0035]
Brief description of the drawings
[0036]
1 shows a specific embodiment of the transmitting microphone of the present invention.
[0037]
In the embodiment shown in FIG. 1, the signal processing for the sound collection output sound
of each of the bone conduction microphone unit and the two directional microphone units is
shown.
[0038]
FIG. 3 shows the output frequency characteristics of the transmission voice of the transmission
microphone of the present invention and the output frequency characteristics of the ambient
noise.
[0039]
Explanation of sign
[0040]
DESCRIPTION OF SYMBOLS 1 Earpiece type ear canal insertion body 2 Bone conduction
03-05-2019
11
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
03-05-2019
12