JPH0436520B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a composite type speaker suitable for a speaker in a small portable audio device such as a radio receiver, a tape recorder, a tape recorder with a radio receiver, or a speaker for a headphone. It is related to speakers.

Conventional configurations and their problems The reason why small portable audio equipment such as radio receivers, tape recorders, and tape recorders with radio receivers has been rapidly increasing in recent years is due to the way people interact with music in their daily lives. In addition to the social aspects that have changed, technologically it has become possible to make mechanical parts smaller and more precise, making them extremely compact. As these devices have become more compact, the speakers or headsets that actually produce the sound have also become smaller and lighter. but,
As speakers become smaller, it becomes difficult to reproduce bass sounds, and for this reason, bass sounds are currently reproduced by compensating with electric circuits or configuring mechanical resonant circuits.

Full-range speakers are the mainstream for speakers used in small portable audio equipment and headphones. However, when trying to reproduce bass sounds with a small-diameter speaker, the diaphragm inevitably needs to move with a large amplitude.If this is a full-range speaker, the diaphragm moves with a large amplitude at a low frequency and the high frequency signal is I will be joining. This causes the high frequency signal to be modulated by the low frequency movement of the diaphragm. This is Doppler distortion, and when the low frequency is ₁ and the high frequency is ₂ , sounds of ₂ ± ₁ , ₂ ± _{2 1} , ... are generated. Unlike high-frequency distortion, this distorted sound is dissonant, so there is a problem in that it significantly deteriorates the quality of reproduced sound.

Figure 1 shows a speaker used in conventional small portable audio equipment. In Fig. 1, 1 is an integral diaphragm made of thermoformed polymer film, 2 is a voice coil that converts an input electrical input signal into driving force,
3 is the frame, 4 is the top plate of the magnetic circuit,
5 is a magnet, and 6 is a magnetic circuit yoke.

However, in such a conventional speaker, a full-band electrical signal with low frequencies boosted is applied to the voice coil 2. Since the diaphragm 1 generates a large amplitude with low frequency signals, it modulates high frequency signal components. This is Doppler distortion, and an example of Doppler distortion is shown in FIG. Furthermore, the above-mentioned conventional speaker has a large diameter diaphragm, and split vibration appears at low frequencies, and very high frequencies are not reproduced. FIG. 3 shows the reproduction frequency characteristics of a conventional speaker. As you can see from Figure 3, frequencies below 400Hz are not reproduced. To do this, we try to boost the electrical signal and add it to the speaker for reproduction. As a result, the diaphragm had a large amplitude, resulting in split vibrations appearing at 2.5KHz and 3KHz, with the disadvantage that higher frequencies could not be reproduced.

Purpose of the Invention The present invention is intended to eliminate such conventional drawbacks, and aims to provide a composite speaker that can reduce Doppler distortion and increase the reproduction limit frequency in the high range. .

Composition of the Invention The composite speaker of the present invention has an integral circular diaphragm whose cross section passing through the central axis has a plurality of uneven shapes, the outermost part of which is fixed to a magnetic circuit or a frame, and the middle part of which is fixed to a magnetic circuit or frame. A voice coil that is fixed and mechanically divided into two parts, an inner part and an outer part, and concentrically connected to each of the inner part and the outer part, is connected to each of the concentric magnetic gaps made up of the above magnetic circuit by a piston movement. It is supported as much as possible.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. 4 and 5 show an embodiment of the present invention. In FIGS. 4 and 5, 11
is an integral circular diaphragm made by thermoforming a polymer film whose cross section passing through the central axis is uneven, and has three concentric valley lines. 12' and 12 are first and second voice coils, the first voice coil 12' being joined to the valley line at the innermost circumferential position of the diaphragm 11, and the second voice coil 12 is joined to the valley line at the outer circumferential position of the diaphragm 11. Reference numeral 13 denotes a frame for holding a magnetic circuit, which will be described later.In this frame 13, there is provided a magnetic circuit consisting of an annular top plate 14, an annular magnet 15, and an annular yoke 16 having an E-shaped cross section. . In this magnetic circuit, a first annular magnetic gap is formed between the outer peripheral surface of a center pole 16' provided at the center of the annular yoke 16 and the inner peripheral surface of the top plate 14. A second annular magnetic gap is formed between the circumferential surface and the outer circumferential surface of the top plate 14. Then, the diaphragm 1
The outermost circumference of the diaphragm 11 is fixed to the frame 13, and the valley line at the middle position of the diaphragm 11 is fixed to the top plate 14 with an adhesive 17, so that the diaphragm 11 is mechanically connected to the inner side. A first voice coil 1 is divided into two parts so as to vibrate on the outside, and is connected to the inside diaphragm part.
2' is a first magnetic gap of the magnetic circuit, and a second voice coil 12 connected to the outer diaphragm portion is supported by the second magnetic gap of the magnetic circuit for piston movement. . Therefore, the integrated diaphragm 11 functions as a woofer with the voice coil 12 driving the outer diaphragm portion and the voice coil 1 driving the inner diaphragm portion.
2' works as a tweeter. The fixing means for mechanically dividing the diaphragm 11 into two parts, inside and outside, is a top plate 14 as shown in FIGS. 6 and 7.
It may be fixed with an adhesive 17 to an adhesive ring 18 provided in the. Further, the diaphragm 11 can be fixed to the top plate 14 or the adhesive ring 18 by mechanical bonding such as thermocompression bonding instead of using an adhesive.

FIG. 8 shows the frequency characteristics of the speaker of this example. In Fig. 8, is the sound pressure frequency characteristic of the outer woofer, and is the sound pressure frequency characteristic with boosted bass.
is the sound pressure frequency characteristic of the inner tweeter, and FIG. 9 is the total sound pressure frequency characteristic.

Effects of the Invention As detailed above, according to the present invention, the outermost periphery of a circular diaphragm whose cross section through which the central axis passes has a plurality of concave and convex shapes is fixed to a magnetic circuit or a frame, and the intermediate portion is fixed to the magnetic circuit or a frame. A voice coil fixed to the frame and mechanically divided into two parts, an inner part and an outer part, and concentrically joined to each of the inner part and the outer part, is supported by a concentric magnetic gap made up of the above magnetic circuit. Therefore, the woofer and tweeter, which move with large amplitude, can be separated, which reduces the occurrence of Topppler distortion and provides high-quality reproduced sound. Furthermore, the diaphragm diameter of the tweeter is small, and the frequency at which split vibrations occur is low, so it has the advantage of being able to reproduce up to high frequencies.
Furthermore, it is possible to provide a small, lightweight, and inexpensive coaxial speaker.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a conventional composite speaker, Fig. 2 is a schematic diagram of generation of cross-modulation distortion in the same speaker, Fig. 3 is a sound pressure frequency characteristic diagram of the same speaker, and Fig. 4 is a diagram of the composite speaker of the present invention. 5 is an enlarged sectional view of the main parts of the same speaker; FIG. 6 is a sectional view showing another embodiment of the composite speaker of the present invention; FIG.
The figures are enlarged cross-sectional views of the main parts of the same speaker, Figures 8 and 9.
The figure is a sound pressure frequency characteristic diagram of the same speaker. 11...Diaphragm, 12, 12'...Voice coil, 13...Frame, 14...Top plate, 15...Magnet, 16...Yoke, 17
... Adhesive, 18 ... Adhesive ring.

Claims (1)

[Claims] 1 The outermost periphery of an integrated circular diaphragm whose cross section passing through the central axis has a plurality of irregularities is fixed to a magnetic circuit or frame, and the middle part is fixed to the magnetic circuit or frame to mechanically connect the inner and outer parts. A composite speaker comprising a voice coil which is divided into two parts and is connected to each of the inner and outer diaphragm parts and is supported by each of the magnetic gaps formed concentrically in the magnetic circuit.