JPH0335695

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DESCRIPTION JPH0335695
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
Hi-Fi speaker, and more particularly to a dome-shaped speaker for improving input resistance
and improving directivity. 2. Related Art (2) In recent years, there has been a demand for a
speaker apparatus for Hi-Fi with high input resistance and improvement in directivity that can
reproduce uniform timbre regardless of where you listen. As a known technique for improving
directivity, a dome-shaped speaker that receives high-pitched sound is dealt with in a direction to
make the effective diameter of the diaphragm smaller, but the voice coil diameter becomes
smaller and the input resistance is improved. Has not improved. The above-mentioned
conventional dome-shaped speaker will be described below with reference to the drawings. FIG. 2
shows a cross section of a conventional dome-shaped speaker. In FIG. 2, 1 is a bottom plate, 2 is
a ring-shaped magnet, 3 is a top plate, and the bottom plate 1 and the top plate 3 sandwich the
magnet 2 to form a magnetic circuit to form an annular magnetic gap 4 Form. A voice coil 5 is
wound around a voice coil bobbin 6 and is suspended so as to be able to vibrate in the magnetic
gap 4. A dome diaphragm 7 is formed of a thin metal foil, and a rubber coating is applied to the
outer periphery of the dome diaphragm 7 so that a roll edge 8 formed of a non-air-permeable
cloth is fixed. The outer peripheral portion of the roll edge 8 is fixed to the spacer 9 of the spacer
9 and is held by the baffle plate 10. 11 is a screw for fixing the baffle plate. The operation of the
dome-shaped speaker configured as described above will be described below. First, the voice coil
5 is suspended in the magnetic gap 4. When an electric signal is applied, the voice coil 5 vibrates
according to Fleming's left-hand rule to vibrate the dome diaphragm 7 via the voice coil bobbin
6. Explaining from the viewpoint of the directivity of sound, according to the following equation,
at the same frequency, if the directivity angle (θ) becomes a wide angle, the sound pressure level
decreases, and it is further determined by the ratio of diaphragm diameter to wavelength
Therefore, the effective diaphragm diameter including the roll edge 8 had to be reduced. velocity
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potential a at a directivity angle (θ), effective vibration radius φ0; velocity potential δP on an
axis; sound pressure Jl, type 1 Bessel function 0 0; density k of air, wave constant problem to be
solved by the invention However, in the above-mentioned conventional configuration, the voice
coil diameter becomes small, so the dome shaped speaker (the improvement of the input
resistance against the two can not be achieved, There was a problem of the burning of the voice
coil.
SUMMARY OF THE INVENTION The present invention solves the above-described conventional
problems, and provides a dome-shaped spinono that aims to improve the input resistance to a
dome-shaped speaker and improve the directivity. Means for Solving the Problems In order to
solve the problems, the dome-shaped speaker according to the present invention comprises a
metal-based material such as titanium or a non-metallic hard dome diaphragm such as mica, and
a vent fixed on the outer periphery thereof. It is constructed by using a heat-formed thin cloth,
paper or the like or a heat-formed edge which is impregnated with a phenol resin or the like into
a relatively coarse thin cloth to secure air permeability. Operation With this configuration, the
voice coil diameter is increased to improve human resistance, and since the edge has air
permeability, the effective diaphragm diameter is reduced, and directivity can be improved.
Embodiment An embodiment of the present invention will be described with reference to the
drawings. In FIG. 1, 13 is a bottom plate, 14 is a ring-shaped magnet, 15 is a top plate, and the
bottom plate 13 and the top plate 15 sandwich the magnet 14 to form a magnetic circuit 12, and
this magnetic circuit An annular magnetic air gap 16 is formed at 12. A voice coil 17 is wound
around a voice coil bobbin 18 and is suspended so as to be able to vibrate in the magnetic gap
16. A dome diaphragm 19 is made of thin metal foil, and its outer periphery is fixed to a roll edge
20 made of city or paper. The outer peripheral portion of the roll edge 20 is fixed on the spacer
21 and sandwiched by the baffle plate 22. Reference numeral 23 denotes a screw for fixing the
baffle plate 22. Here, the roll edge 20 has a highly breathable characteristic of being thermally
molded by impregnating a relatively coarse, thin cloth with a phenol resin or the like. The other
configuration is the same as the configuration described in the conventional example. The
operation of the dome-shaped speaker configured as described above will be described below.
The driving force acting on the voice coil 17 by the electrical signal is similar to that described in
the prior art. In the case of this embodiment, even if the voice coil diameter is increased, the
effective diaphragm diameter is reduced because the roll edge 20 has air permeability, and the
directivity in the high frequency range can be improved. As described above, according to the
present embodiment, even if the voice coil diameter is increased, a relatively coarse-grained thin
cloth is formed on the outer peripheral portion of the dome diaphragm 19 formed of metal thin
foil. By fixing the roll edge 20 having the characteristic of high air permeability, which is
thermoformed by impregnating it, the effective diaphragm diameter is reduced, and the
directivity in the high frequency range can be improved.
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As described above, according to the present invention, the present invention is formed of a
metallic diaphragm such as titanium or a non-metallic dome diaphragm such as mica, and a
highly breathable thin cloth or paper fixed to the outer periphery thereof. The voice coil diameter
is increased by forming the edge using a heat-formed edge by impregnating a relatively coarse,
thin cloth with a phenolic resin or the like to ensure breathability. Since human power is
improved and the edge has air permeability, the effective diaphragm diameter can be reduced,
and a dome-shaped speaker can be realized which can improve directivity in the high frequency
range.
[0002]
Brief description of the drawings
[0003]
FIG. 1 is a cross-sectional view of a dome-shaped speaker according to an embodiment of the
present invention, and FIG. 2 is a cross-sectional view of a conventional dome-shaped speaker.
12 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · magnetic gap, 17 ...... voice coil, 18 ...... voice coil bobbin, one ...... dome diaphragm, 20
...... edge, 21 ...... spacers 22 ······ Baffle plate, 23 ········ Bis.
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