JPH02248196

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DESCRIPTION JPH02248196
[0001]
FIELD OF THE INVENTION The present invention relates to a speaker for Hi-Fi, and more
particularly to a dome-shaped speaker for medium and high-tone sound reproduction where it is
desired to flatten sound pressure frequency characteristics, in particular to improve sharp peaks
in high frequency reproduction limit frequencies. . Prior Art In recent years, diaphragms of domeshaped loudspeakers have also made remarkable progress with noble materials, and materials of
high E / ρ have been introduced. A dome-shaped speaker using such a hard diaphragm
generates a sharp peak at its high frequency reproduction limit frequency. Conventionally, in the
case of improving a dome-shaped speaker having such a sharp peak, as a known technique, there
has been a means such as sticking a braking piece on the back of the dome portion. The abovementioned conventional dome-shaped speaker will be described below with reference to the
drawings. FIG. 4 shows a cross section of a conventional dome-shaped speaker. In FIG. 4, 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 hold the magnet 2 to form an annular magnetic gap 4. 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 has a cylindrical portion to which the voice coil
bobbin 6 is fixed and a flat portion 8 at the outer peripheral portion, and an inner peripheral
portion of a roll elastic ') 9 formed of a cloth It is fixed to the flat portion 8. The outer peripheral
portion of the roll edge 9 is fixed on a spacer 1 o and held by a buckle plate 11. Reference
numeral 12 denotes a braking piece fixed to the top back surface of the dome diaphragm 7. 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, and when an electric signal is applied,
the voice coil 5 vibrates up and down according to Fleming's left hand rule to vibrate the dome
diaphragm 7 via the voice coil bobbin 6. At a relatively low frequency, vibration is performed in
phase with the vibration of the voice coil V5, but at a high frequency, the dome diaphragm 7
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vibrates in its own resonance mode to generate sharp peaks and dips. A viscoelastic damping
piece 12 formed of a mass and a resistor is attached in the vicinity of the top of the dome
diaphragm 7, which vibrates remarkably in the inherent resonance mode of the dome diaphragm
7, to try to suppress sharp peaks and dips. It is a thing. SUMMARY OF THE INVENTION However,
in the above-described conventional configuration, it is not possible to attach an amount that acts
as a resistor enough for the damping piece 12 to act as a vibration system mass, and
furthermore, a sharp resonance whose vibration mode is axisymmetric Therefore, it has a
problem that it is not possible to effectively damp resonance to suppress sharp peaks and dips.
An object of the present invention is to solve the above-mentioned conventional problems, and an
object of the present invention is to provide a dome-shaped speaker capable of improving sharp
peaks and dips in high frequency reproduction limit frequencies. In order to solve this problem,
in order to solve this problem, the dome-shaped speaker according to the present invention
comprises an edge formed of a rubber cloth coated thin surface and a dome diaphragm on the
inner periphery thereof, and the dome vibration described above An elliptical through hole is
provided in the center of the plate, and a diaphragm having a metal foil or non-metallic dome
diaphragm attached to the surface or the back of the peripheral part of the through hole is
configured. It is done. In this configuration, the hard dome diaphragm is attached to the rubbercoated thin film dome diaphragm and the central oval portion except the through hole, so that
the hard dome diaphragm is The stiffness is non-axisymmetric to disperse the inherent resonance
mode, and the damping action of the rubber coating dome diaphragm suppresses peaks and dips.
Embodiments Hereinafter, one embodiment of the present invention will be described with
reference to the drawings. In FIG. 1, 21 is a bottom plate, 22 is a ring-shaped magnet, 23 is a top
plate, and the bottom plate 21 and the top plate 23 sandwich the magnet 22 to form an annular
magnetic gap 24. A voice coil 25 is wound around a voice coil bobbin 26 and is suspended so as
to be able to vibrate in the magnetic gap 24. Reference numeral 2 denotes a dome diaphragm
having a cylindrical portion to which the voice coil bobbin 26 is fixed at the outer peripheral
portion, a flat portion 28 and an edge portion 29. The outer peripheral portion of the edge
portion 29 is fixed on the spacer 30 and held by the baffle plate 31. 2 and 3 show a crosssectional view and a rear view of a vibration system of a dome-shaped speaker according to an
embodiment of the present invention. In FIG. 2 and FIG. 3, reference numeral 29 is an edge
portion formed of a rubber-coated thin cloth, and has a dome portion 32 formed in a dome shape
on the inner peripheral portion thereof. Reference numeral 33 denotes an elliptical through hole
provided at the center of the dome portion 32. Reference numeral 34 denotes a metal foil or
nonmetal hard dome diaphragm attached to the surface of the dome portion 320. The operation
of the dome-shaped speaker configured as described above will be described below. The drive
acting on the voice coil 25 by the application of the electric signal is the same as that described
in the prior art. In the case of the present embodiment, even if the drive signal has a high
frequency, the bonding area between the hard dome diaphragm 34 and the dome portion 32
formed of a thin rubber-coated thin film with rigidity is circumferential. , And the natural
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resonance of the hard dome diaphragm 34 is dispersed, and the dome portion 32 acts as a
braking piece.
As described above, according to this embodiment, the edge portion 29 and the dome portion 32
are formed on the inner periphery of the edge portion 29 by a thin cloth having a rubber coating
on the surface, and the elliptical portion is transmitted to the central portion of the dome portion
32. The hard dome diaphragm 34 is made of rubber by using the dome diaphragm formed by
providing the holes 33 and pasting the node dome diaphragm 34 made of metal foil on the
surface of the periphery thereof. The rigidity of the hard dome diaphragm 34 is non-axially
symmetric due to the solid dome cloth coated with thin cloth and the part pasted at the central
part of the oval through hole 33. Intrinsic resonant modes are dispersed, and peak damping can
be suppressed by the damping action of the rubber-coated dome diaphragm. As described above,
according to the present invention, an edge is formed of a thin cloth having a rubber coating on
the surface, and a dome diaphragm is formed on the inner periphery thereof, and an elliptical
through hole is provided in the central portion of the dome diaphragm. To suppress the sharp
peak in the high-frequency reproduction limit frequency by providing a diaphragm configured by
sticking a metal foil or nonmetal node / dome diaphragm on the surface or back surface of the
peripheral portion And flat sound pressure frequency characteristics can be realized.
[0002]
Brief description of the drawings
[0003]
1 is a cross-sectional view of a dome-shaped speaker according to the present invention, FIG. 2 is
a rear view of a dome diaphragm used for the speaker, FIG. 3 is an A-O-B cross-sectional view of
FIG. Fig. 6 shows a cross-sectional view of a dome-shaped speaker of
21 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Dome diaphragm 28: Flat portion 29: Edge portion 30:
Spacer 31 Baffle plate 32: Dome portion 33: 33 ... through hole, 34 ... hard dome diaphragm.
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