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DESCRIPTION JP2013251660

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DESCRIPTION JP2013251660
Abstract: The present invention provides a headphone unit and a headphone which can obtain a
well-balanced frequency characteristic while securing a sense of bass in the low frequency range.
A magnetic circuit (5) having a magnetic gap, a flange member (7) for supporting the magnetic
circuit at the center, a diaphragm (8) attached to the front side of the flange member, and a voice
coil (4) The headphone unit is configured to be mounted and a voice coil is disposed in the
magnetic gap. The flange member 7 is formed with a large number of through holes 11 for
communicating the space on the back side of the diaphragm 8 with the back side of the flange
member, and a first acoustic resistance member 13 for selectively closing the through holes. And
the second acoustic resistive material 15 is disposed at a predetermined distance H with respect
to the back surface of the flange member, and the width W between the second acoustic resistive
material and the flange member 7. A slit-like sound path gap 16a is formed. [Selected figure]
Figure 3
ヘッドホンユニットおよびヘッドホン
[0001]
The present invention relates to a headphone unit capable of improving frequency characteristics
in a low frequency range and realizing balanced frequency characteristics, and a headphone
using the headphone unit.
[0002]
In general, a headphone unit, in particular a dynamic headphone unit, is well known as a
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magnetic circuit having a magnetic gap, a flange member for supporting the magnetic circuit in
the center, a diaphragm attached to the front side of the flange member, and the vibration. A
voice coil is attached to a part of the plate, and the voice coil is arranged in the magnetic gap of
the magnetic circuit.
Then, by causing a voice current to flow through the voice coil, the diaphragm is made to
oscillate, and a voice is reproduced based on the amplitude of the diaphragm.
[0003]
By the way, in the headphone unit having the above-described configuration, a configuration is
employed in which a plurality of through holes are formed in the flange member, and an acoustic
resistance material such as non-woven fabric is attached to the back surface side of the flange
member, for example. That is, the frequency characteristic and the low frequency characteristic
of the headphone unit are adjusted by selectively closing the through hole with the acoustic
resistance material.
[0004]
16 and 17 show an example of a conventional headphone unit. FIG. 16 is a perspective view, and
FIG. 17 is a central cross-sectional view and a rear view. In the cross-sectional view shown in FIG.
17, reference numeral 1 denotes a yoke formed in a bottomed cylindrical shape, in which the
magnet 2 and the pole piece 3 are disposed, and the opening edge of the yoke 1 and the pole
piece 3 A magnetic gap 4 is formed between the outer peripheral edge and the magnetic circuit
5. An annular flange member 7 is attached to the outer peripheral surface of the yoke 1
constituting the magnetic circuit 5, and the magnetic circuit 5 is supported at the center by the
flange member 7, and the front surface of the flange member 7 is A diaphragm 8 is attached to
the side.
[0005]
The diaphragm 8 is composed of a center dome 8a constituting a central portion side and a sub
dome 8b whose periphery is attached to the flange member 7, and a voice coil is formed at the
boundary between the center dome 8a and the sub dome 8b. (Indicated by 4 with the same
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reference numeral as the magnetic gap. The voice coil 4 is disposed in the magnetic gap of the
magnetic circuit 5 described above. In addition, the code | symbol 9 has shown the protector
which covers the front surface of the said diaphragm 8. As shown in FIG.
[0006]
Fig. 16 is a perspective view of the headphone unit as viewed from the back side, and Fig. 16 (a)
is a state in which the acoustic resistance material 13 formed of a non-woven fabric or the like is
separated; The state in which the acoustic resistance material 13 is attached to the back surface
of the flange member 7 is shown. As shown in FIG. 16, a large number of circular through holes
11 are formed in the annular flange member 7 along the circumferential direction. The through
hole 11 is formed to communicate with the back side of the diaphragm 8, that is, the back side of
the sub dome 8b of the diaphragm 8.
[0007]
Further, on the back surface of the flange member 7, an acoustic resistance material 13 formed
in an annular shape by non-woven fabric or the like is attached. The acoustic resistance material
13 is formed with a hole 13 a at a portion corresponding to the through hole 11 which is not
closed by the acoustic resistance material 13. That is, in the example shown in FIG. 16 and FIG.
17, the other through holes are covered with the acoustic resistance material 13 except for one
through hole 11 which is not covered with the acoustic resistance material 13. In the following,
for convenience of explanation, the through holes not covered by the acoustic resistance material
13 are indicated by the reference numeral 11, and the through holes covered by the acoustic
resistance material 13 are indicated by the reference numeral 12.
[0008]
In the headphone unit having the above-described configuration, the air flow rate is adjusted by
adjusting the density of, for example, a non-woven fabric as the acoustic resistance material 13 in
the plurality of holes 12 covered by the acoustic resistance material 13. It can be flattened. In
addition, the size and number of the holes 11 not covered by the acoustic resistance material 13
function to adjust the amplitude amount of the lowest resonance frequency f0 of the diaphragm
8, and also greatly affect the sound pressure and the braking force of the bass region. Have an
important role. Furthermore, the size and position of the holes 11 not covered by the acoustic
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resistance material 13 greatly affect the rolling action of the diaphragm 8.
[0009]
FIG. 18 shows an acoustic equivalent circuit diagram of the conventional headphone unit shown
in FIGS. In FIG. 18, r0 is the equivalent resistance of the diaphragm 8, m0 is the equivalent mass
of the diaphragm 8, s0 is the equivalent stiffness of the diaphragm 8, mu is the equivalent mass
of the hole 11 not covered by the acoustic resistance material 13, and ru is The equivalent
resistance of the hole 12 covered by the acoustic resistance material 13 is shown, and P shows
the sound wave (sound pressure) reaching the ear. In the equivalent circuit diagram shown in
FIG. 18, mu functions as a low pass filter on frequency characteristics, and ru functions as a high
pass filter.
[0010]
As described above, a headphone unit in which a plurality of through holes are formed in the
flange member, and by selectively closing the through holes with an acoustic resistance material,
the balance between the low frequency characteristics and the overall frequency characteristics
is adjusted Many proposals have been made conventionally, and are disclosed, for example, in
Patent Documents 1 and 2.
[0011]
Japanese Utility Model Laid-Open Publication No. 2-88395 Japanese Laid-Open Patent
Publication No. 2005-86220
[0012]
By the way, in the above-described configuration of the headphone unit, in order to obtain a large
sound pressure (a feeling of volume) in the bass range, the amplitude of the diaphragm 8 can be
secured by reducing the load applied to the diaphragm 8 to facilitate movement. Ru.
As the means, it adjusts in the direction to which the number of the holes 11 which are not
covered by the above-mentioned acoustic resistance material 13 is increased.
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[0013]
When the number of holes 11 not covered by the acoustic resistance material 13 is increased,
the amplitude near the lowest resonance frequency f0 of the diaphragm 8 increases and the
sound pressure also increases, but the peak near the f0 in the frequency characteristic increases
The problem of
The appearance of a mountain near this f0 is caused by the increase of the peak value Q of the
resonance, which is due to the reduction of the damping force of the diaphragm 8, and the socalled "popped" sound Is not desirable in terms of sound quality.
[0014]
In addition, when the number and area of the holes 11 not covered by the acoustic resistance
material 13 are increased, a problem also occurs that the mechanical impedance balance is lost,
and the load applied to the diaphragm 8 is reduced as described above. As a result, a rolling
phenomenon occurs in the diaphragm 8, and the appearance of defective products that cause
abnormal noise is also increased. Furthermore, as the load applied to the diaphragm 8 is reduced,
the amount of amplitude of the diaphragm in the vicinity of the f0 becomes excessive. As a result,
various problems occur such that the input resistance characteristic of the headphone unit also
decreases.
[0015]
In order to eliminate the above-mentioned problems and to obtain a headphone unit of stable
quality, it is necessary to suppress the number and the area of the holes 11 not covered by the
acoustic resistance material 13. However, since reducing the number of holes 11 not covered by
the acoustic resistance material 13 acts in the direction of applying a load to the diaphragm to
reduce the amplitude, the sound pressure drop near the f0 can not be avoided, and Not only the
lack of feeling of mass occurs, but also the balance of the frequency characteristics is broken.
[0016]
This invention is made based on the above-mentioned technical viewpoint, and even if it
increases the number of the holes which are not covered by acoustic resistance material,
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generation | occurrence | production of the above-mentioned fault can be prevented and it is low.
An object of the present invention is to provide a headphone unit and headphones capable of
securing a sense of volume in a sound range and obtaining well-balanced frequency
characteristics.
[0017]
The headphone unit according to the present invention, which was made to solve the abovementioned problems, comprises a magnetic circuit provided with a magnetic gap, a flange
member supporting the magnetic circuit in the center, and a vibration attached to the front side
of the flange member. A headphone unit having a voice coil attached to a plate and a part of the
diaphragm and the voice coil disposed in a magnetic gap of the magnetic circuit, wherein the
flange member has a back surface of the diaphragm. A plurality of through holes for
communicating the space on the side to the back surface of the flange member are formed, and a
first acoustic resistance material for selectively closing the through holes is disposed, and further,
predetermined to the back surface of the flange member Slit having a width W between the
second acoustic resistive material and the flange member, and a second acoustic resistive
material disposed at a distance H of Wherein the sound path gap is formed.
[0018]
In this case, in one preferable form, the second acoustic resistance material is formed in a ring
shape, and the inner peripheral edge thereof is attached to an outward curved surface formed in
a part of the flange member; A configuration in which a slit-like sound path gap having the width
W is formed between the outer peripheral edge of the acoustic resistance material 2 and the
inward curved surface formed in a part of the flange member is employed.
[0019]
Further, in another preferable embodiment, the second acoustic resistance material is formed in a
ring shape, and the outer peripheral edge thereof is attached to an inward curved surface formed
in a part of the flange member; A configuration in which a slit-like sound path gap having the
width W is formed between the inner peripheral edge of the second acoustic resistance material
and the outward curved surface formed on a part of the flange member is employed. .
[0020]
Further, in another preferable embodiment, the second acoustic resistance material is formed in a
ring shape, and the outer peripheral edge thereof is attached to a unit fixing holder disposed so
as to surround the flange member, A configuration in which a slit-like sound path gap having the
width W is formed between the inner peripheral edge of the acoustic resistance material and the
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outward curved surface formed on a part of the flange member is employed.
[0021]
In still another preferred embodiment, a convex rib is formed on the back surface of the flange
member so as to surround each of the through holes formed in the flange member, and the
second acoustic resistance material is the one described above. A slit-like sound path having the
width W between a part of the flange member and a notch formed in the second acoustic
resistance member while being attached to the flange member via a convex rib A configuration in
which a void is formed is employed.
[0022]
The headphone according to the present invention is configured by including the headphone unit
described in any of the above.
[0023]
According to the headphone unit and the headphone using the same according to the present
invention, the second acoustic resistance material is disposed at a predetermined distance H from
the back surface of the flange member, and the second acoustic resistance material is provided. A
slit-like sound path gap having a width W is formed between the above and the flange member.
According to this configuration, sound waves before and after f0 formed in the flange member
and entering and exiting the through hole not covered by the first acoustic resistance material
are radiated to the back surface of the unit through the slit-like sound path gap At the same time,
it is emitted to the back of the unit through the second acoustically resistive material formed in a
ring shape.
[0024]
Therefore, an appropriate load is applied to the diaphragm by increasing the number of holes not
covered by the first acoustic resistance material and adjusting the slit-like sound path gap width
by the second acoustic resistance material, for example. Therefore, it is possible to provide a
headphone unit capable of suppressing the occurrence of mechanical impedance imbalance and
significant rolling (air movement) phenomenon, and as a result, flattening of sound pressure and
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input resistance. it can.
As a result, it is possible to suppress the mountain (peak value Q of resonance) which tends to be
generated near the above-mentioned f0, and to obtain a headphone unit having frequency
characteristics well balanced with the sense of volume in the bass range.
[0025]
They are a center sectional view and a rear view showing a semi-finished state of a headphone
unit according to the present invention.
It is the center sectional view and the back view which showed the 1st form of the headphone
unit concerning this invention.
It is sectional drawing which expanded and showed the principal part in the 1st form shown in
FIG.
It is a center sectional view and a back view showing the 2nd form of a headphone unit.
It is an equivalent circuit schematic of the headphone unit which concerns on a 1st and 2nd
form.
It is sectional drawing which shows the example which comprised the headphone using the
headphone unit which concerns on a 1st form. It is an exploded view in the case of attaching the
headphone unit concerning the 3rd form to a baffle board. It is sectional drawing and a partial
rear view which show the state attached to the baffle board similarly. It is sectional drawing
which expanded and showed the principal part in the 3rd form shown in FIG. It is sectional
drawing which shows the example which comprised the headphone using the headphone unit
which concerns on a 3rd form. It is an external view and sectional drawing of a flange member in
the headphone unit concerning the 4th form mainly. It is the external view and sectional drawing
which showed the structure of the 2nd acoustic resistance material attached to the flange
member shown in FIG. It is an external view and sectional drawing which show the state which
attached the 2nd acoustic resistance material shown in FIG. 12 to the flange member shown in
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FIG. It is the figure which showed the frequency characteristic and the 2nd harmonic distortion
characteristic in the headphone unit concerning this invention. It is the figure which showed the
frequency characteristic and the 2nd harmonic distortion characteristic in the conventional
headphone unit. It is the external appearance block diagram which showed an example of the
conventional headphone unit. It is a center sectional view and a rear view similarly. It is an
equivalent circuit schematic of the conventional headphone unit.
[0026]
Hereinafter, a headphone unit according to the present invention and a headphone using the
same will be described based on an embodiment shown in the drawings. In the respective
drawings described below, the same reference numerals are given to the parts performing the
same functions as the parts shown in FIG. 16 and FIG. 17 described above, and therefore the
detailed description thereof will be appropriately omitted. In each of the drawings described
below, reference numerals may be attached to representative portions, and other reference
numerals may be omitted.
[0027]
FIGS. 1 to 3 show a first embodiment of a headphone unit according to the present invention.
The basic configuration of the first embodiment is the same as the configuration of the
conventional headphone unit shown in FIGS. 16 to 17 described above. However, the number of
through holes 11 not covered with the acoustic resistance material 13 is increased as compared
with the configuration of the conventional headphone unit. That is, in the embodiment shown in
FIG. 1, the through holes 11 which are not covered by the acoustic resistance material 13 are
disposed at three places at equal intervals in the circumferential direction.
[0028]
According to the configuration shown in FIG. 1, the number of the through holes 11 not covered
by the acoustic resistance material 13 increases, so the load applied to the diaphragm 8 is
reduced and the diaphragm 8 is easily oscillated. Technical problems will also arise. . Therefore,
in the first embodiment, as shown in FIG. 2, the acoustic resistance material 15 is further
disposed on the back surface side of the flange member 7. In the following, the above-described
acoustic resistance material 13 made of non-woven fabric or the like for selectively closing
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through holes formed in the flange member 7 is referred to as a first acoustic resistance material,
and is further disposed on the back surface side of the flange member 7 The acoustic resistance
material 15 is referred to as a second acoustic resistance material.
[0029]
As the second acoustic resistance material 15, for example, a felt material formed in a ring shape
is used. In the embodiment shown in FIG. 2, the inner peripheral edge of the second acoustic
resistance material 15 formed in a ring shape is used. Is attached to a part of the flange member
7. And as the principal part was expanded and shown in FIG. 3, while the said flange member 7 is
formed in cyclic | annular form whole, the cross section of the peripheral part is formed in a Ushape, and the outward curved surface 7a and The inward curved surfaces 7b are formed to face
each other.
[0030]
An inner peripheral edge of the second acoustic resistance member 15 formed in a ring shape is
attached to the outward curved surface 7a using, for example, an adhesive. Thereby, a slit-like
sound path gap 16a having a width W is annularly formed between the outer peripheral edge of
the second acoustic resistance member 15 and the inward curved surface 7b of the flange
member 7. Further, the second acoustic resistance material 15 is disposed at a predetermined
distance H with respect to the back surface of the flange member 7. In FIG. 3, the thickness of the
second acoustic resistance material 15 is indicated by T, and the area of the through hole 11 is
indicated by Aφ.
[0031]
In the first embodiment shown in FIGS. 1 to 3, the equivalent resistance value (flow resistance) by
the second acoustic resistance material 15 is the above-mentioned Aφ (hole 11 not blocked by
the first acoustic resistance material 13). Area (number and position), H (distance between the
flange member 7 and the second acoustic resistance material 15), T (thickness of the second
acoustic resistance material 15), W (slit width of the slit-like sound path gap 16a) The equivalent
resistance value can be adjusted by a combination of these factors. In FIG. 3, reference numeral
21 denotes a part of the baffle plate that supports the flange member 7 of the headphone unit.
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[0032]
FIG. 4 shows a second embodiment of the headphone unit according to the present invention.
The second embodiment is basically the same as the first embodiment described based on FIGS. 1
to 3 described above. In the second embodiment, the ring-shaped second acoustic resistance
member 15 has an outer peripheral edge formed in a part of the flange member 7 and an inward
curved surface (reference numeral 7b shown in FIG. 3). Slit-like member having a width W
between the inner peripheral edge of the second acoustic resistance member 15 and the outward
curved surface (reference numeral 7a shown in FIG. 3) formed on a part of the flange member
The sound passage gap 16b is formed.
[0033]
Also in the second embodiment of the headphone unit shown in FIG. 4, the equivalent resistance
value (flow resistance) by the second acoustic resistance material 15 is determined by the
respective elements shown in FIG. 3, that is, the A.phi., H, T and W. It is possible to adjust the
equivalent resistance value by a combination of these.
[0034]
FIG. 5 shows an acoustic equivalent circuit diagram of the headphone unit of the first
embodiment shown in FIGS. 1 to 3 or the headphone unit of the second embodiment shown in
FIG.
According to the equivalent circuit diagram shown in FIG. 5, r1 (the equivalent resistance of the
second acoustic resistance material 15), s1 (the flange member 7 and the second acoustic
resistance material 15) are further added to the equivalent circuit diagram shown in FIG.
Between H and H) and m1 (equivalent mass of slit-like sound path gaps 16a and 16b) are added.
[0035]
This is due to the second acoustic resistance material 15 described above, and an appropriate
load can be applied to the diaphragm 8 by adjusting r1 functioning as a high pass filter and m1
functioning as a low pass filter in terms of frequency characteristics. Thus, it is possible to
provide a headphone unit capable of obtaining a well-balanced frequency characteristic while
securing a feeling of low-pitched tone.
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[0036]
FIG. 6 is a cross-sectional view showing an example in which a headphone is configured using the
headphone unit of the first embodiment shown in FIGS. 1 to 3.
That is, the headphone unit is attached to the opening 21a formed at the center of the baffle
plate 21 as shown in FIG. 6 (a). The peripheral edge of the baffle plate 21 is U-shaped in cross
section to form an annular groove 21b, and the ear pad 22 is attached to the front side of the
headphone unit using the groove 21b. In addition, a housing 23 that covers the back surface of
the headphone unit is attached to the back surface side of the baffle plate 21, and a headphone is
thus configured.
[0037]
7 to 9 show a third embodiment of the headphone unit. The ring-shaped second acoustic
resistance material 15 used in the third embodiment is attached to the unit fixing holder 25 as
shown in FIG. The unit fixing holder 25 is formed in an annular shape, and a locking step 25a is
formed on the inner peripheral surface of the unit fixing holder 25 so as to surround the flange
member 7 of the headphone unit.
[0038]
Further, in the unit fixing holder 25, through holes 25 b of mounting screws are formed at four
places around the unit fixing holder 25, and the unit fixing holder 25 is a baffle using the
mounting screws 26 inserted through the through holes 25 b. It is attached to the plate 21. At
this time, the flange member 7 of the headphone unit is locked to the locking step 25a formed on
the unit fixing holder 25, and the headphone unit is fixed to the baffle plate 21 as shown in FIG.
8A. . With this configuration, a slit-like sound path gap 16 b is formed between the inner
peripheral edge of the second acoustic resistance member 15 and the flange member 7.
[0039]
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FIG. 9 is an enlarged view of the main part of the third embodiment, which shows a part
corresponding to the main part of the first embodiment shown in FIG. 3 described above. That is,
a slit-like sound path gap 16b having a width W is annularly formed between the inner
peripheral edge of the second acoustic resistance member 15 and the outward curved surface 7a
of the flange member 7. Further, the second acoustic resistance member 15 is disposed at a
predetermined distance H with respect to the back surface of the flange member 7 as in the
example shown in FIG. 3 described above. Also in FIG. 9, the thickness of the second acoustic
resistance material 15 is indicated by T, and the area of the through hole 11 is indicated by Aφ.
[0040]
Similarly, in the headphone unit of the third embodiment, the equivalent resistance value (flow
resistance) by the second acoustic resistance member 15 is Aφ (a hole 11 not blocked by the
first acoustic resistance member 13) shown in FIG. Area (number and position), H (distance
between the flange member 7 and the second acoustic resistance material 15), T (thickness of
the second acoustic resistance material 15), W (slit width of the slit-like sound path gap 16b) The
equivalent resistance value can be adjusted by a combination of these factors. That is, also in the
headphone unit of the third embodiment shown in FIGS. 7 to 9, it can be expressed in the same
manner as the acoustic equivalent circuit diagram shown in FIG. 5 already described, and the
same function and effect can be obtained. .
[0041]
FIG. 10 is a cross-sectional view showing an example in which a headphone is configured using
the headphone unit of the third embodiment shown in FIGS. The configuration example of the
headphones shown in FIG. 10 is the same as the example shown in FIG. 6 (b) described above,
and the corresponding parts are indicated by the same reference numerals. Therefore, the
detailed description is omitted.
[0042]
FIGS. 11 to 13 show a fourth embodiment of the headphone unit, which describes one preferable
example in the case of attaching the above-mentioned second acoustic resistance material 15 to
the flange member 7. In the headphone unit shown in FIGS. 11 to 13, the magnetic circuit
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portion described above is not shown, and in this figure, the configuration of the flange member
7 and the second acoustic resistance member attached thereto are mainly provided. It shows
about 15 composition.
[0043]
As shown in FIG. 11 (a), the flange member 7 has a central portion formed with a recess 7d seen
from the front side for housing a magnetic circuit (not shown), and the front surface of the flange
member 7 is a protector 9 is attached. FIGS. 11 (b) and 11 (c) are cross-sectional views of the
flange member 7 as viewed from the back and from the line A-A in the direction of the arrow.
Also in this embodiment, the first embodiment Similarly, the through holes 11 not covered with
the first acoustic resistance material 13 are arranged in the flange member 7 at three positions at
equal intervals in the circumferential direction.
[0044]
Further, on the back surface of the flange member 7, convex ribs are provided so as to surround
the through holes 11 not covered by the first acoustic resistance material 13 and the through
holes 12 covered with the first acoustic resistance material 13. 7e are radially further projected
in a concentric manner. Reference numeral 7f shown in FIG. 11 (b) indicates a terminal area in
which a connection terminal for supplying a voice current to the voice coil is disposed.
[0045]
On the other hand, FIG. 12 shows the configuration of the second acoustic resistance material 15
made of a felt material or the like attached to the flange member 7 shown in FIG. 11, and FIG. 12
(a) is a front view and FIG. Is shown in a rear view, and FIG. 12 (c) is shown in a cross-sectional
view as viewed in the direction of the arrow from line B-B in FIG.
[0046]
In the second acoustic resistance material 15, the arrangement positions of the through holes 11
not covered with the first acoustic resistance material 13 and the through holes 12 covered with
the first acoustic resistance material 13 are on the back surface of the flange member 7. It is
formed so that each can be covered.
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That is, except for a portion corresponding to the terminal area 7f formed in the flange member
7, the whole is formed in a C shape so as to cover the arrangement positions of the through holes
11 and 12.
[0047]
In addition, on the surface of the second acoustic resistance member 15 to be attached to the
back surface of the flange member 7, a glued portion 15b shown in wide black is applied. The
glued portion 15 b is provided at a position corresponding to the convex rib 7 e formed on the
flange member 7. Further, notches 15a are formed at three positions corresponding to the
positions of the through holes 11 not covered by the first acoustic resistance material 13 in the
flange member 7. That is, at the position of the through hole 11 which is not covered with the
first acoustic resistance material 13 in the second acoustic resistance material 15 formed in a Cshape as a whole, the notch portion 15a has an outer peripheral edge in an arc shape. It is
formed to be cut out.
[0048]
FIG. 13 shows a headphone unit formed by attaching the second acoustic resistance material 15
shown in FIG. 12 to the back surface of the flange member 7 shown in FIG. 11. FIG. 13 (a) is a
side view FIGS. 13 (b) and 13 (c) are cross-sectional views of the headphone unit as viewed from
the back and from the line C-C in the arrow direction.
[0049]
In the fourth embodiment according to the present invention, as shown in FIG. 13, the gluing
portion 15b applied to the acoustic resistance material 15 is put together and attached to the
convex rib 7e formed on the flange member 7. .
Thus, slit-like sound path gaps 16c are formed by the notches 15a at three locations
corresponding to the positions of the through holes 11 not covered by the first acoustic
resistance material 13 in the flange member 7.
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[0050]
According to the fourth embodiment shown in FIGS. 11 to 13, the portion corresponding to the
through hole 12 covered with the first acoustic resistance material 13 is formed by the convex
rib 7 e formed on the flange member 7. The second acoustic resistance material 15 is in the
opposite state through the space portion. Further, in a portion corresponding to the through hole
11 which is not covered by the first acoustic resistance material 13, a second acoustic resistance
is formed through a space portion formed by the convex rib 7e formed in the flange member 7.
The material 15 is brought into a state of facing each other, and a slit-like sound path gap 16c is
formed by the notch 15a applied to the second acoustic resistance material 15.
[0051]
With this configuration, the second acoustic resistance member 15 is disposed with a
predetermined distance H to the back surface of the flange member 7, and the second acoustic
resistance member 15 and a part of the flange member 7 A slit-like sound path gap 16c having a
width W is formed between the two. Therefore, by adjusting the thickness of the second acoustic
resistance material 15, the slit width of the sound path gap 16c, and the like, it is possible to
control the volume feeling and the frequency characteristic of the low tone range of the
headphone unit. The same effects as those of the first to third embodiments can be obtained.
[0052]
FIGS. 14 and 15 respectively show the frequency characteristics and the second harmonic
distortion characteristics in the headphone unit according to the present invention and the
headphone unit shown as the conventional example, and the diagrams shown in the upper side of
each drawing. Shows the frequency characteristics, and the diagram shown at the bottom of each
figure shows the second harmonic distortion characteristics.
[0053]
First, FIG. 15 shows the characteristics of the headphone unit shown as a conventional example
in which the second acoustic resistance member 15 is not provided, and a1 and b1 shown by
solid lines are shown in FIGS. 16 and 17 already described. In the conventional example shown,
the frequency characteristic and the second harmonic distortion characteristic in the case where
the number of the through holes 11 not blocked by the first acoustic resistance material 13 is
one are shown.
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[0054]
Further, a2 and b2 indicated by broken lines indicate frequency characteristics and second
harmonic distortion characteristics in the case where the number of through holes 11 not
similarly blocked by the first acoustic resistance material 13 is two. The illustrated a3 and b3
indicate frequency characteristics and second harmonic distortion characteristics in the case
where the number of the through holes 11 not blocked by the first acoustic resistance material
13 is three.
[0055]
In general, in this type of headphone unit, the region of 50 Hz to 1.5 kHz is called a piston
motion region, and second harmonic distortion (non-linear distortion) is small in inverse linear
proportion to frequency and small Have the following characteristics.
In the headphone unit shown as the conventional example, as can be understood from the
characteristics shown in FIG. 15, it can be understood that second harmonic distortion (nonlinear distortion) is easily generated if the low frequency characteristics around f0 are
suppressed .
[0056]
That is, when the number of the through holes 11 not blocked by the first acoustic resistance
material 13 is reduced to three (characteristic b3) → two (characteristic b2) → one
(characteristic b1), the vicinity of 91.4 Hz and 317 Hz An abrupt change (disturbance) occurs in
the second harmonic distortion.
This indicates the deterioration of phase characteristics and transient characteristics.
Therefore, in the headphone unit having the configuration shown in FIGS. 16 and 17 shown as
the conventional example, the adjustment to reduce the number of through holes 11 not blocked
by the first acoustic resistance material 13 in order to obtain good bass characteristics is It can
be understood that the second harmonic distortion characteristic is deteriorated, which is not
preferable.
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[0057]
Next, FIG. 14 shows the characteristics of the headphone unit according to the present invention,
and c1 and d1 shown by solid lines and c2 and d2 shown by broken lines are according to the
present invention shown in FIG. 3 already described. The characteristics of the headphone unit
are shown, and c1 and d1 show the characteristics when the distance between the flange
member 7 and the second acoustic resistance member 15 shown in FIG. 3 is 1 / 2H, and c2 and
d2 Indicates the characteristic when the distance is doubled, that is, H. In FIG. 14, the
characteristics of a3 and b3 shown in FIG. 15 are added and shown for comparison.
[0058]
As can be understood from the characteristics shown in FIG. 14, according to the headphone unit
according to the present invention, the addition of the second acoustic resistance material 15
makes it possible to suppress the amplitude amount of the diaphragm 8 before and after f0. , And
c1 and c2, well-balanced low-pass characteristics can be obtained. Further, as indicated by d1
and d2, a large disturbance is not generated in the second harmonic distortion, and a wellbalanced low frequency characteristic can be obtained. Furthermore, since a suitable acoustic
load is added to the diaphragm 8 by the second acoustic resistance member 15, the acoustic
impedance rises, and as a result, as indicated by c1 and c2, the sound in the range of 1 to 5 kHz
It also contributes to raising the pressure.
[0059]
As can be understood from the comparison of the characteristic diagrams shown in FIG. 14 and
FIG. 15 described above, the headphone unit according to the present invention and the
headphones using the same have the unique effects and advantages described in the column of
the above-described effects of the invention. You can get
[0060]
Reference Signs List 1 yoke 2 magnet 3 pole piece 4 magnetic gap (voice coil) 5 magnetic circuit
7 flange member 7 a outward curved surface 7 b inward curved surface 7 d concave portion 7 e
convex rib 7 f terminal area 8 diaphragm 8 a center dome 8 b sub dome 9 Protector 11 Through
hole (not closed by the first acoustic resistance material) 12 Through hole (closed by the first
acoustic resistance material) 13 first acoustic resistance material 13a Penetration hole 15 second
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acoustic resistance material 15a Notched part 15b Glued part 16a to 16c Slit-shaped sound
passage gap 21 baffle plate 21a opening 21b groove 22 ear pad 23 housing 25 unit fixing holder
25a locking step 25b through hole 26 mounting screw
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