JPH0583795

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DESCRIPTION JPH0583795
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
cone type speaker.
[0002]
2. Description of the Related Art In a so-called multi-way speaker system combining, for example,
each speaker for bass and treble for each band of a sound source, it is considered ideal that each
sound source position is on the same plane . In order to realize this, conventionally, for example,
as shown in FIG. 2A, a method of disposing the high-tone speaker 2 behind the mounting
position of the bass speaker 1 or, conversely, as shown in FIG. 2B. As such, a method is adopted
in which the bass speaker 1 is disposed forward with respect to the mounting position of the
treble speaker 2.
[0003]
The reason why the positional relationship between the bass speaker 1 and the treble speaker 2
is relatively moved and arranged as a method of aligning the positions of the respective sound
sources in this way is that the sound source position of the cone type speaker is apparent as
shown in FIG. Thus, this is based on the hypothesis that it is in the vicinity of the junction point 5
between the cone 3 and the voice coil 4 as a diaphragm. Certainly, the speed at which the sound
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propagates through the corn paper 3 is not so fast, and it is more practical to use the junction
point 5 as a sound source in terms of hearing.
[0004]
However, although the speed of sound propagating through the corn paper 3 is slow, the corn
paper 3 is usually solid and therefore faster than the speed of propagation in the air, and
therefore, FIG. In such a conventional speaker, a clear temporal deviation occurs between the
sound pressure P1 of the sound generated from the junction point 5 and the sound pressure P2
of the sound generated from any point 6 on the outer periphery of the cone paper 3 As a result,
the waveform transmission is not faithful, and the reproduced sound becomes indistinct.
[0005]
SUMMARY OF THE INVENTION The present invention has been made in view of the above
circumstances, and provides a cone-shaped speaker capable of obtaining clear reproduced sound
faithful to waveform transmission and excellent in directivity.
[0006]
SUMMARY OF THE INVENTION The cone type loudspeaker of the present invention has a
peripheral portion fixed to a frame 8 as shown in FIG. 1, for example, and the cone type
diaphragm 3 mounted on the frame 8 has this cone. A cone type speaker having a covering
member 7 disposed along the mold diaphragm 3 from the outer peripheral part to the central
part of the conical diaphragm 3, and an opening 7a is provided in the central part of the covering
member 7. And the path from the outer peripheral portion 3a of the cone-shaped diaphragm 3 to
a predetermined observation position 3a 'of the sound generated through the opening 7a, and
the central portion 3b of the cone-shaped diaphragm 3 Formed so that the path to another
observation position 3b 'on the plane opposite to this cone-shaped speaker and on the same
plane as this observation position has approximately the same length A.
[0007]
According to the cone type speaker of the present invention, the covering member having the
opening at the center portion is disposed on the front of the diaphragm and along the diaphragm,
so that the waveform transmission is faithful and the reproduced sound is clear. In addition,
directivity is also improved without any deterioration in frequency characteristics.
[0008]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present
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invention will be described in detail with reference to FIG.
[0009]
In the present embodiment, for example, a rigid covering member 4 is disposed on the front
surface of the cone paper 3 as a diaphragm and along the cone paper 3 from its outer periphery
toward the center, and the peripheral portion of the covering member 4 is Securely attach to part
8.
Further, an opening 7 a of a predetermined shape is provided in the central portion of the
covering member 4.
The shape of the opening 7a may be arbitrary.
For example, a circle, an ellipse, a square, etc. can be considered.
When the opening 7a is formed, the paths of the sound generated from the outer peripheral
portion 3a of the cone paper 3 and the sound generated from the central portion 3b have the
same length, that is, from the outer peripheral portion 3a to the front of the speaker The length
up to the observation position 3a 'and the length of the observation position 3b' which is on the
same plane as the position 3a 'from the central portion 3b to the front surface of the speaker are
substantially the same.
As a result, the sound path difference d1 between the inner and outer peripheries of the cone
paper 3 is substantially shortened to the sound path difference d2 as shown in FIG.
[0010]
Therefore, there is no temporal shift between the sound pressure of the sound generated from
the outer peripheral portion 3a of the cone 3 and the sound pressure of the sound generated
from the central portion 3b, and the waveform transmission becomes faithful, and the
reproduced sound Becomes clear.
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[0011]
For example, considering a frequency that decreases 3 dB in the direction of 30 ° and 10 dB in
the direction of 60 ° as the limit of directivity on hi-fi reproduction, this frequency fr is
expressed by the following equation, where the effective radius of the opening 7a of the covering
member 7 is a Is represented by
[0013]
Where C is the velocity of sound.
As the effective radius a of the opening 7a is smaller than the number 1, the frequency fr
becomes larger, and the directivity is improved.
[0014]
Further, assuming that the volume of the portion surrounded by the plane of the opening 7a and
the cone paper 3 shown by oblique lines in FIG. 1 is V, the resonance frequency fH at that time is
expressed by the following equation.
[0016]
As the volume V is smaller than the equation (2), the resonance frequency fH becomes larger,
and the directivity is improved.
That is, it can be understood from the above Equations 1 and 2 that the radiation area is
substantially reduced, and the directivity is improved.
[0017]
Therefore, by setting the position of the covering member 7 with respect to the cone paper 3 and
the shape of the opening 7a in consideration of the above-described sound path, the phases of
the sound sources from the outer periphery and the center of the cone paper 3 are matched. In
other words, faithful waveform transmission is possible, and directivity is also improved.
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In addition, the loudspeaker according to the present invention as described above may be used
alone or in combination of a plurality of bands.
[0018]
As described above, according to the present invention, the covering member having an opening
at the central portion is disposed on the front surface of the diaphragm and along the diaphragm,
so waveform transmission is faithful and reproduction sound is generated. The directivity is also
improved without any deterioration in the frequency characteristics.
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