JP2009194669

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DESCRIPTION JP2009194669
A ribbon-type microphone ribbon capable of suppressing partial resonance, a method of
manufacturing the same, and a ribbon-type microphone in which a defect based on partial
resonance does not appear in frequency response characteristics by using the ribbon. A magnet
for forming a magnetic gap, a ribbon diaphragm arranged in a magnetic gap and vibrated by
sound waves, and an output of an electric signal generated by the ribbon diaphragm vibrating in
the magnetic gap A ribbon diaphragm 60 for use in a ribbon microphone provided with an
electrode and a frame for holding a magnet and the electrode. A large corrugated pattern 62
formed with ridges 66 directed in a direction perpendicular to the longitudinal direction of the
ribbon diaphragm 60 in a longitudinally advancing form, and a smaller length than the
corrugated pattern 62, the longitudinal length of the ribbon diaphragm 60 And a pattern 64
formed along the direction. [Selected figure] Figure 1
Ribbon-type microphone ribbon, method of manufacturing the same, and ribbon-type
microphone
[0001]
The present invention relates to a ribbon for a ribbon microphone capable of suppressing
deterioration in frequency response due to partial resonance of the ribbon, a method of
manufacturing the same, and a ribbon microphone.
[0002]
The ribbon microphone mainly comprises a magnet for forming a magnetic field and a ribbon
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diaphragm.
The magnets are disposed on both sides of the ribbon diaphragm, and a magnetic field is formed
between the magnets on both sides. The ribbon diaphragm is provided with an appropriate
tension to hold both end portions in the length direction and disposed in the magnetic field. The
ribbon diaphragm receives a sound wave and vibrates in a magnetic field, whereby a current
corresponding to the sound wave flows through the ribbon diaphragm and the sound wave is
converted into an electric signal. Conventionally, an aluminum foil is widely used as a material of
the ribbon diaphragm. Aluminum is suitable as a ribbon diaphragm of a ribbon microphone
because it has better conductivity and lighter specific gravity than other metal materials.
[0003]
FIG. 5 shows an example of a common ribbon microphone. 6 and 7 show a ribbon microphone
unit incorporated in the ribbon microphone. In FIG. 5, in the ribbon microphone 1, a housing of a
microphone is configured by a tubular base 6 and a microphone case 2 connected to an upper
end of the base 6. In the housing, the ribbon microphone unit 3 is attached to an appropriate
support member fixed to the base 6, and the microphone unit 3 is covered by the microphone
case 2. The lower end portion of the base 6 is a connector portion 16 for connecting a
microphone cable for guiding an output signal of the microphone to an external circuit.
[0004]
As also shown in FIGS. 6 and 7, the ribbon microphone unit 3 includes a frame 7 formed in a
rectangular frame shape long in the vertical direction. On the inner surface of the frame 7, a pair
of permanent magnets 4, 4 is fixed on both sides along the long side direction with a
predetermined distance between both permanent magnets 4, 4. The permanent magnets 4 and 4
are magnetized in the width direction (left and right direction in FIGS. 5 and 6). The
magnetization directions of the pair of permanent magnets 4 and 4 are the same, and a parallel
magnetic field is formed between the permanent magnets 4 and 4.
[0005]
In the above-mentioned parallel magnetic field, a ribbon type diaphragm (hereinafter sometimes
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referred to simply as "ribbon") 5 which also serves as a diaphragm and a conductor is disposed.
The ribbon 5 is an elongated strip-shaped member, and both ends in the lengthwise direction are
fixed to electrode lead portions 18 and 18 provided at both ends in the lengthwise direction of
the frame 7. The electrode lead portions 18 and 18 are insulated from the frame 7, and the
ribbon 5 is conducted in a conductive state by sandwiching both ends of the ribbon 5 with the
holding member 8 and the ribbon 5 in a state where the ribbon 5 is given a suitable tension.
Hold Both ends of the ribbon 5 are formed in a triangular wave shape by alternately bending the
other portions 51 except for the electrode lead portions 18 and 18 at constant intervals. The
direction of the line formed by the bending, that is, the direction of the line drawn by the crests
and valleys of the triangular wave is the width direction of the ribbon 5, and the lines are formed
at regular intervals. Hereinafter, the corrugated end portions 51 of the ribbon 5 will be referred
to as corrugated end portions 51. A terminal plate 9 is overlapped on the holding members 8 at
the both ends. The terminal plates 9 are electrically connected to the ends of the ribbon 5
through the holding members 8 so that signals from the ribbon microphone unit 3 are output
from the terminal plates 9. . The middle portion of the ribbon 5 sandwiched by the corrugated
end 51 of the ribbon 5 is a direction perpendicular to the direction of the line drawn by the
crests and valleys of the triangular wave of the corrugated end 51, ie, a line in the lengthwise
direction of the ribbon 5. The top and bottom of the triangular wave are formed along the waveshaped middle portion 52.
[0006]
The ribbon 5 receives the sound wave and vibrates in accordance with the sound wave. The
vibration direction is a direction crossing the magnetic flux between the permanent magnets 4
and 4, and the ribbon 5 made of a conductor generates electric power by crossing the magnetic
flux, and between the longitudinal ends of the ribbon 5 and hence the electrode lead portions 9
and 9. An electrical signal is generated between them. Since this electrical signal becomes a
signal of frequency and amplitude corresponding to the frequency and amplitude of the ribbon 5,
the sound wave striking the ribbon 5 will be converted into an electrical signal corresponding to
this sound wave. Since the ribbon microphone is an inertial control system, the resonance
frequency of the ribbon 5 needs to be lower than the lower frequency of the sound wave to be
collected, in other words, lower than the lowest frequency of the frequency range in which the
sound can be collected. is there. For this reason, the tension of the ribbon 5 is set extremely low.
As described above, the ribbon 5 achieves low tension by being bent into a corrugated shape.
[0007]
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In the example of the ribbon microphone described above, the middle portion in the length
direction of the ribbon 5 is a waveform middle portion 52 in which the top and the valley bottom
of the triangular wave are formed along the line in the length direction of the ribbon 5. The
ribbons of many conventional ribbon microphones are formed such that the direction of the line
drawn by the crests and troughs of the triangular wave is the width direction of the ribbon over
the entire length. In other words, the triangular wave is formed to travel in the entire length
direction. In order to produce such a ribbon, conventionally, a pair of spur gears in which teeth
consisting of triangular peaks and valleys are formed at regular intervals on the outer periphery
have been used. The pair of spur gears use not only the tooth pitch and radius but also the same
specifications. The worker places a pair of spur gears on a smooth substrate, for example, a glass
substrate, sandwiches the aluminum foil which is the material of the ribbon 5 with the pair of
spur gears, and presses the pair of spur gears against each other. Rotate and feed out the above
material. By doing this, the shape of the teeth of the pair of spur gears is transferred to the
material, and the corrugated ribbon as described above is formed.
[0008]
According to the ribbon manufactured as mentioned above, since the raw material is metal foil
which consists of aluminum etc., the resonance sharpness of mechanical resonance is high. That
is, a peak due to resonance appears sharply. For this reason, there is a problem that resonance
appears in the frequency response, and the sound wave can not be faithfully converted to the
electric signal. FIG. 8 shows the appearance of occurrence of partial resonance in the ribbon
formed such that the direction of the line drawn by the crest and trough of the triangular wave is
the width direction over the entire length direction. As shown by two dotted ovals in FIG. 8,
partial resonance occurs in a portion corresponding to one period and half period of the
triangular wave. Focusing on the part corresponding to the half cycle, this part has a flat surface
and is therefore low in rigidity and easily resonates. FIG. 9 shows frequency response
characteristics of a microphone using such a ribbon. The horizontal axis is frequency, and the
vertical axis is output signal level (unit: dBV). The upper two lines of this graph are measured at
the front and the back, and the lower two lines are measured at the left and right sides. Since the
front and back characteristics are important in a ribbon microphone, focusing on the front and
back characteristics, periodic sharp peaks appear. This is due to the above-mentioned partial
resonance.
[0009]
The partial resonance as described above appears prominently in the ribbon formed so that the
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direction of the line drawn by the crests and troughs of the triangular wave is the width direction
over the entire length. However, partial resonance is also observed in the ribbon in which the
waveform intermediate portion 52 in which the top and the bottom of the triangular wave are
formed along the longitudinal line of the ribbon as shown in FIGS. 5 to 7. The portion
corresponding to the half cycle of the triangular wave is also a flat surface and has low rigidity.
[0010]
As a solution to such problems of the prior art, it is conceivable to adopt the invention described
in Patent Document 1 proposed by the present inventor. In the invention described in Patent
Document 1, the material of the ribbon is placed on the surface of the transfer type formed in the
same shape as the ribbon to be formed and temporarily fixed, and a roller having an elastic
member on the outer peripheral surface The present invention relates to a method of
manufacturing a ribbon microphone ribbon in which the transfer mold surface shape is
transferred to the ribbon material by rolling the elastic member while pressing the elastic
member against the ribbon material. In Patent Document 1, the surface of the transfer type
intermediate portion in the longitudinal direction is subjected to emboss or matte processing,
whereby the emboss or satin is transferred to the intermediate portion in the longitudinal
direction of the ribbon. To some extent it will be higher. Patent Document 1 also describes that
the elastic member of the roller may be formed by electrostatic flocking.
[0011]
According to the invention described in Patent Document 1, the rigidity of the middle portion in
the lengthwise direction of the ribbon can be increased to some extent. However, to the extent
that the texture or texture is formed, the rigidity of the ribbon can not be sufficiently increased,
and the problem of partial resonance can not be solved.
[0012]
JP 2007-49324 A
[0013]
The present invention has been made in view of the problems of the prior art as described above,
and it is an object of the present invention to provide a ribbon microphone ribbon capable of
suppressing partial resonance and a method of manufacturing the same. Accordingly, it is an
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object of the present invention to provide a ribbon microphone in which a failure based on
partial resonance does not appear in frequency response characteristics.
[0014]
A ribbon for a ribbon microphone according to the present invention comprises a magnet
forming a magnetic gap, a ribbon diaphragm arranged in the magnetic gap and vibrating by
sound waves, and the ribbon diaphragm vibrating in the magnetic gap. The ribbon diaphragm
used in a ribbon microphone provided with an electrode for outputting an electric signal
generated by the frame, and the magnet and a frame for holding the electrode, wherein the
ribbon diaphragm travels in the longitudinal direction of the ribbon diaphragm In the form of a
corrugation formed with the ridge line oriented in a direction perpendicular to the longitudinal
direction of the ribbon diaphragm, and smaller than the corrugation pattern formed along the
longitudinal direction of the ribbon diaphragm The most important feature is to have a pattern.
[0015]
A method of manufacturing a ribbon for a ribbon microphone according to the present invention
is a method of manufacturing a ribbon for a ribbon microphone having the above characteristics,
which includes a process of manufacturing a transfer mold for forming a ribbon diaphragm and
the transfer mold. And a transfer step of pressing the material of the ribbon diaphragm against
the formed corrugated surface to transfer the transfer type waveform, and the process of
manufacturing the transfer type is a pattern of the waveform advancing in the longitudinal
direction of the transfer type. A cutting process for forming a pattern in which the ridges of the
waves are oriented in a direction orthogonal to the longitudinal direction of the transfer mold,
and a pattern smaller than the waveform pattern of the transfer mold, the longitudinal direction
of the transfer mold And E) and an etching process for forming a pattern arranged along the Y
direction.
[0016]
If it is only a large pattern of corrugations formed by directing ridges in a direction perpendicular
to the longitudinal direction of the ribbon diaphragm in the longitudinal direction of the ribbon
diaphragm, partial resonance as described above Will occur.
However, by forming a pattern smaller than the pattern of the above-mentioned waveform along
the longitudinal direction of the ribbon diaphragm together with the above-mentioned large
pattern, unevenness with the above-mentioned small pattern is also formed in a portion
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corresponding to a half cycle of the waveform Therefore, the rigidity is enhanced and the
occurrence of partial resonance is suppressed.
Therefore, if the ribbon diaphragm is incorporated into a ribbon microphone unit and then
incorporated into a microphone case to constitute a ribbon microphone, the appearance of sharp
resonance in the frequency response characteristic is suppressed and good frequency response
characteristic is obtained. You can get it.
[0017]
According to the method of manufacturing a ribbon for a ribbon microphone according to the
present invention, the shape of the ribbon diaphragm is smaller than the large pattern of the
waveform advancing in the longitudinal direction and the pattern of the waveform, and the
longitudinal direction of the ribbon diaphragm Even though the shape is complicated, the ribbon
for the ribbon microphone can be easily manufactured only by transferring the transfer type
surface shape to the ribbon diaphragm material.
Moreover, since the said transfer type ¦ mold forms a big pattern of a waveform by cutting and
forms a small pattern by an etching process, manufacture of a transfer type ¦ mold is also easy.
[0018]
Hereinafter, an embodiment of a ribbon for a ribbon microphone, a method of manufacturing the
ribbon and a ribbon microphone according to the present invention will be described with
reference to the drawings.
FIG. 1 (a) shows an embodiment of a ribbon for a ribbon microphone according to the present
invention (hereinafter referred to as "ribbon-shaped diaphragm"), and FIG. 1 (b) carries out one
process of manufacturing the ribbon-shaped diaphragm. The example of the transcription type
for doing is shown. In FIG. 1 (a), the ribbon diaphragm 60 is made of a metal foil having a
thickness of several micrometers, for example, aluminum foil, and the ribbon diaphragm 60 has a
large corrugated pattern 62 and a corrugated pattern 62. Also, a pattern (hereinafter referred to
as a small pattern ) 64 formed along the longitudinal direction of the ribbon diaphragm 60 is
formed. The large corrugated pattern 62 has a triangular cross-sectional shape and travels in the
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longitudinal direction of the ribbon diaphragm 60 and is formed with the ridge 66 directed in the
direction orthogonal to the longitudinal direction of the ribbon diaphragm 60 ing.
[0019]
As shown in FIG. 1A, a large number of the small patterns 64 are arranged in the longitudinal
direction of the ribbon diaphragm 60, and a plurality of rows are also arranged in the direction
perpendicular to the width direction of the ribbon diaphragm 60, ie, the longitudinal direction. It
is arranged. The small pattern 64 is a rectangular pattern, and the long side of the small pattern
64 is disposed in the longitudinal direction of the ribbon diaphragm 60. Further, a plurality of
small rectangular patterns 64 are arranged in the width direction of the ribbon diaphragm 60 by
shifting the positions in the long side direction alternately in the longitudinal direction of the
ribbon diaphragm 60. Therefore, the small patterns 64 are formed in a zigzag shape.
[0020]
Next, an embodiment of a manufacturing process of the ribbon diaphragm 60 will be described.
The manufacturing process of the ribbon diaphragm 60 in which the waveform pattern 62 and
the small pattern 64 are formed is roughly divided into a manufacturing process of a transfer
mold for forming the ribbon diaphragm, and the above-mentioned transfer mold. It consists of a
transfer step of pressing the material of the ribbon diaphragm against the corrugated surface to
transfer the waveform of the transfer type.
[0021]
1 (b), 2 (b) and 3 show the transfer for producing the ribbon diaphragm 60 by forming the
pattern 62 and the small pattern 64 on, for example, aluminum foil which is a material of the
ribbon diaphragm. An example of a mold 70 is shown. The transfer mold 70 has a corrugated
surface 72 of triangular cross-sectional shape for transferring the corrugated pattern 62 of the
ribbon diaphragm 60, and is arranged on the corrugated surface 72 along the longitudinal
direction of the transfer mold 70. And a small pattern transfer surface consisting of small
patterns arranged in a plurality of rows in the width direction of the transfer mold 70. The small
pattern transfer surface is a surface for transferring the small pattern 64. The corrugated surface
72 is formed to advance in the longitudinal direction of the transfer mold 70 and to have the
ridge line 76 in a direction orthogonal to the longitudinal direction of the transfer mold 70. The
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small pattern transfer surface is composed of an infinite number of rectangular patterns, and
these patterns alternate the long side direction with the longitudinal direction of the transfer
mold and the long side direction with the longitudinal direction of the transfer mold 70. A
plurality of rows are arranged in the width direction of the transfer mold 70 in a staggered
manner.
[0022]
The corrugated surface 72 of the transfer mold 70 is formed by mechanical cutting of, for
example, a metal block as a material of the transfer mold. After the corrugated surface 72 is
formed on the transfer mold 70, the corrugated surface 72 is etched to form the small pattern
transfer surface. The etching method may be a known method. For example, a photoresist is
applied to the entire surface of the corrugated surface 72, exposed to light in accordance with
the target pattern, a pattern consisting of exposed and unexposed portions is formed, and then
the small pattern transfer surface is etched Form As shown in FIGS. 3A and 3B, the small pattern
transfer surface is composed of a concave portion 74 and a convex portion 75 formed by
removing the surface by etching. The concave portion 74 is surrounded by the convex portion
75, and the concave portion 74 and the convex portion 75 forming the small pattern transfer
surface have the long side direction of the rectangle directed to the longitudinal direction of the
transfer mold 70 and the above long side direction. A plurality of rows are arranged in the width
direction of the transfer mold 70 by alternately shifting positions in the longitudinal direction of
the transfer mold 70.
[0023]
Incidentally, one pitch of the small pattern 64 in the longitudinal direction of the ribbon
diaphragm 60 is, for example, 2.48 mm, and the pitch of the corrugated pattern 62 may be the
same as or different from this. The depth of the recess 74 in the transfer mold 70 for forming the
small pattern 64 may be about 0.05 mm. It is desirable that the corners of the convex portion 75
be finished to have a shape which is chamfered in an arc shape so as not to be sharp. If the
corner of the convex portion 75 is sharp, the ribbon material may be easily hit by the sharp
corner in the transfer step described below.
[0024]
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Next, it is subjected to a transfer process using the transfer mold 70 formed as described above,
and the surface shape of the transfer mold 70 is transferred to the ribbon material. This transfer
step is carried out as follows. A ribbon material made of an elongated metal foil is placed on the
corrugated surface 72 of the transfer mold 70, and the ribbon material is pressed onto the
corrugated surface with a soft brush-like member. As the brush-like member, it is possible to use,
for example, a flocked roller in which fibrous hairs are uniformly formed on the surface. The
fibrous hair is made of short fibers, and the length and thickness of the fibers are determined in
accordance with the size and depth of the unevenness of the corrugated surface 72 of the
transfer mold 70. In order to obtain such a flocked surface 14, it is preferable to use electrostatic
flocking technology. The flocking roller is rolled in the longitudinal direction of the material
while pressing the flocking roller hair against the material of the ribbon diaphragm. The hair of
the flocked roller is pressed lightly against the material, and the shape of the corrugated surface
72 of the transfer form 70, ie, the aforementioned large pattern 62 and small pattern 64 of the
corrugated shape are formed on the material by transfer. Ru. The transfer process using such a
flocked roller can adopt the same one as that described in Patent Document 1.
[0025]
FIG. 2 (a) shows only the state where the large pattern 62 of the above-mentioned waveform is
formed on the material of the ribbon diaphragm 60, and FIG. 1 (a) shows the state where the
small pattern 64 is formed together with the pattern 62. Is shown. In FIG. 2A, reference numeral
66 denotes a ridge line generated in the above-mentioned pattern 62 of the waveform, and this
ridge line 6 is directed in a direction orthogonal to the longitudinal direction of the ribbon, that
is, in the width direction of the ribbon.
[0026]
The material of the transfer mold 70 may be metal or plastic. In order to temporarily fix the
ribbon material placed on the surface of the transfer mold 70, an appropriate number of exhaust
holes may be formed in the transfer mold 70 so as to extend from the back surface (bottom
surface) of the transfer mold 70 to the surface. The ribbon material is placed on the corrugated
surface 72 of the transfer mold 70, exhausted from the exhaust hole, and a negative pressure is
applied between the corrugated surface 72 of the transfer mold 70 and the ribbon material to
form a ribbon material on the surface of the transfer mold 70. It can be temporarily fixed. The
exhaust pressure at this time may be a weak negative pressure that does not cause misalignment
of the ribbon material.
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[0027]
As the brush-like member, a flat-shaped flocked brush may be used instead of the flocked roller.
In addition, as a flocked brush having a flat shape, a brush may be used in which fibrous hairs
are uniformly flocked on substantially the entire lower surface of a weight on a flat plate having
an appropriate weight.
[0028]
When transferring using a brush implanted on the lower surface of the flat weight, the transfer
mold 70 may be mounted on a vibrator (not shown). Attach the transfer mold 70 on the vibrator,
place the ribbon material on the transfer mold 70 and temporarily fix it if necessary, and place
the flat flocked brush on the ribbon material in the direction in which its hair contacts the ribbon
material. Load and activate the shaker. Vibration is applied to the transfer type 70, the ribbon
material, and the flocked brush by the vibrator, and the flocked brush moves relative to the
ribbon material. The weight of the entire flocked brush is dispersed through the soft bristles of
the flocked brush and added to the ribbon material, and the ribbon material is pressed against
the corrugated surface 72 of the transfer mold 70 to transfer the corrugated surface of the
corrugated surface 72 to the ribbon material Be done.
[0029]
The technique of transferring to a ribbon using a brush and an exciter implanted on the lower
surface of the flat weight as described above may be the technique described in Japanese Patent
Application No. 2007-273127 according to the application of the present applicant. .
[0030]
The corrugated surface 72 is composed of a large triangular wave pattern and a small pattern
consisting of the concave portion 74 and the convex portion 75. The large pattern and the small
pattern are transferred to the ribbon material to complete the ribbon diaphragm 60.
[0031]
The ribbon diaphragm 60 manufactured in this manner is attached to a frame and disposed in a
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magnetic field as shown in FIGS. 6 and 7 to complete a microphone unit of a ribbon microphone.
The ribbon diaphragm 60 bends and vibrates a portion of the corrugated pattern 62 by receiving
the sound wave.
Since this vibration is performed in the magnetic gap as described above, an electrical signal
corresponding to the vibration is generated at both ends of the diaphragm 60, and
electroacoustic conversion is performed. The microphone unit can be made into a ribbon type
microphone by incorporating it in a microphone case as shown in FIG. 5, and a signal can be
output from a connector incorporated in the microphone case.
[0032]
FIG. 4 shows the frequency response characteristics of the ribbon microphone according to the
embodiment of the present invention under the same conditions as the characteristics of the
conventional example shown in FIG. In the measurement of characteristics, in order to compare
with the frequency response characteristic of the conventional ribbon microphone shown in FIG.
9, only the configuration of the ribbon diaphragm was changed, and the other specifications were
measured with the same. Comparing the frequency response characteristics shown in FIG. 4 with
the frequency response characteristics shown in FIG. 9, in the upper two characteristic diagrams
showing the front and back characteristics, the level of the periodic peak is low and the peak
sharpness is It is getting smaller. The reason is that, in addition to the pattern 62 of the
triangular waveform, the small pattern 64 smaller than the pattern 62 is formed on the ribbon
diaphragm 60, thereby forming the portion of the pattern 62 of the triangular waveform. Of the
ribbon-type diaphragm 60 and the partial resonance of the ribbon diaphragm 60 is suppressed.
[0033]
The ribbon microphone ribbon concerning this invention and the Example of the transcription ¦
transfer type used for manufacture of this ribbon are shown, (a) is a front view of the said ribbon,
(b) is sectional drawing of the said transcription ¦ transfer type. Similarly, a ribbon for a ribbon
microphone according to the above embodiment and a transfer type used for manufacturing the
ribbon are shown. (A) is a front view of the ribbon, (b) is a bottom view of the transfer type. The
said transfer type is shown, (a) is an enlarged front view which cuts off and shows a part of
length direction, (b) is side surface sectional drawing. It is a characteristic line which shows the
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frequency response characteristic in the Example of the ribbon type microphone concerning this
invention. It is a partially sectioned front view showing an example of an internal configuration of
a conventionally known ribbon microphone. It is a front view which shows the example of the
conventionally known ribbon type microphone unit. It is side surface sectional drawing of the
conventional example of the said ribbon type microphone unit. It is a schematic diagram for
demonstrating the partial resonance which arises in the ribbon-type diaphragm used for the said
conventional bon-type microphone unit. FIG. 7 is a characteristic diagram showing frequency
response characteristics in an example of a conventional ribbon microphone.
Explanation of sign
[0034]
DESCRIPTION OF SYMBOLS 1 ribbon type microphone 2 microphone case 3 ribbon type
microphone unit 4 magnet 5 ribbon type diaphragm 7 frame 60 ribbon type diaphragm 62
waveform pattern 64 small pattern 66 ridge 70 transfer type 72 corrugated surface 74 concave
75 convex
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