JPS58215194A - Speaker system - Google Patents

Abstract

PURPOSE:To prevent securely a speaker from being destroyed without causing the pause on reproduced sound for any source, by providing an inductor in dependence on temperature having a specified Curie point in its network for a speaker system which reproduces a digital signal converted from an analog audio signal. CONSTITUTION:If an excessive input signal is supplied to a tweeter 5, a corresponding current runs in an inductor 4. Therefore, a coil 4b of the inductor 4 is heated equally as a voice coil of the tweeter 5, and a core member 4a is also heated. If spontaneous magnetization is gradually reduced and comes to near a Curie point where the spontaneous magnetization becomes zero, the value of an L becomes small because its magnetic permeability mu is extremely lowered, and the frequency characteristics of a high pass filter 2 shifts to a higher frequency side. As the result, energy to be supplied to the tweeter 5 is greatly limited so that the tweeter is prevented from being destroyed due to excessive input, and better reproduced sound is obtained without the pause of sound.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker system, which is suitable for use when reproducing digital signals converted from analog audio signals.

In general, speaker systems are configured with a 2-way system in which the band is divided into two for bass and treble, or a 3-way system in which the band is divided into three for bass, midrange, and treble. The treble speaker is called a tweeter, and the mid-back speaker is called a squawkat.

By the way, in such a speaker system, the speaker may be destroyed by an excessively large input signal button, and in most cases, the tweeter is destroyed. This tweeter often breaks down due to thermal damage such as burnout of the voice coil used in it. In other words, in conventional music sources, music energy in the low and mid range occupies most of the music energy, and the power applied to the tweeter is small, so it was designed that way.However, recently, digital audio sources have been designed to As the number of sources that have a large dynamic range and a considerable amount of hidden energy increases in the field of technology, there are increasing opportunities for the tweeter of a speaker system to be exposed to excessive input signals.

A digital audio disk (hereinafter referred to as DAD 5) is known as an example of a digital audio source. This DAD has the following five features: it has the advantage that noise is less likely to be mixed into the signal than conventional analog discs, and it can also record signals on the disc with a wide dynamic range.

Comparing conventional LP discs (hereinafter referred to as LPD) and DAD, as shown in Figure 1, the maximum dynamo range of the 5kLPD is limited to the midrange around 1 kHz, and it is are reduced to about 40 dB, respectively, whereas ZuDAD can provide approximately the same dynamic range of about 90 dB over a wide range over the entire area.

If a DAD with such a wide dynamic range is reproduced and the reproduced signal is directly amplified by a conventional audio system and applied to the speaker, excessive power will be applied to the speaker and the speaker will be destroyed. Special 17
Power amplifiers receive signals with special peak levels that are higher than conventional ones, so if you use the same volume setting as before, the signal waveform will often be clipped, and this clipped waveform will have extremely high peak levels. The tweeter is destroyed because it contains frequency components.

Conventionally, a temperature relay or the like was inserted in series with the speaker system network to prevent the tweeter from being destroyed, but such measures tend to cause malfunction due to variations in the set temperature, and the operating status cannot be signaled. Since this is performed by turning on and off the sound, there are disadvantages such as interruptions in the sound and the inability to obtain satisfactory reproduced sound.

In view of this, the present invention provides a speaker system that can reliably prevent damage to the speaker without causing any interruption in the reproduced sound regardless of the source.

In this invention, an inductor with a large temperature dependence is used as a component of the network that divides the input signal into multiple bands, converts the electrical signal that causes destruction into heat, and uses this heat to create a speaker that is easily destroyed. The purpose is to control the turnover frequency of the tweeter filter to protect the speaker system from excessive input.

Hereinafter, an embodiment of the present invention will be explained in detail based on FIGS. 2 to 5, taking as an example a case in which an embodiment of the present invention is applied to a three-way speaker system.

Figure 2 shows the circuit configuration of this embodiment. In the figure, (1) is an input terminal to which the output signal from the power amplifier is supplied, although not shown, and (2) is a high-frequency bypass filter. It consists of a capacitor (3) and an inductor (4) with large temperature dependence according to the present invention. (5) is a tweeter. Reference numeral (6) is a bandpass filter for mid-range sounds, which is composed of a series-connected coil (7), a capacitor (8), a parallel-connected coil (9), and a capacitor α1. 0
υ is Skoka. Also, (12) is a low-pass filter for bass, with a coil 0 and a capacitor (14).
, and aω is Woo.

For example, as shown in Figure 3, the inductor (4) used in the high-frequency pass filter (21K) consists of a core member (4a) and a coil (4b) wound around the core member (4a). The core member (4a) is made to react to the heat generated by the coil (4b) and reach a predetermined Curie point.For example, the core member (4a) of the
As for a), ordinary ferrite is used, but barium etc. are mixed with it, and the quintile point is set at a predetermined temperature at which the speaker will not suffer thermal damage, for example, 80°C.
The K should be set to an extremely low value such as ℃. Therefore, in the inductor (4), since the magnetic permeability μ of the core member is extremely reduced near the Curie point, the value of L can be made small. Note that since the core member (4a) has a heat capacity of 1, in order to lower the thermal time constant of μ, the coil (4a)
b) The entire inductor (4) is connected to the heat insulating member Q as shown by the broken line in Fig. 3 so that the heat generated in
6).

In a speaker system using an inductor (4) having such a structure, if an excessive input signal is now supplied to the tweeter (5), a considerable amount of current will also flow through the inductor (4). ) coil (4b)
The core member (4a) also heats up due to the heat generated by the outer coil (4b), and its spontaneous magnetization gradually decreases. And the core member (4a
) near the Curie point, where the spontaneous magnetization of Since the energy supplied to the tweeter (5) is significantly limited, the tweeter (5) is prevented from being destroyed by excessive input. The inductance of the inductor (4) at this time is the heat generation and the magnetic permeability μ of the core member (4a).
is moved to a perfectly balanced position. In FIG. 4, the solid line C shows the frequency characteristics of the low-pass filter 0 for the woofer σ noise, and the solid line d shows the frequency characteristics of the band-pass filter (6) for the squawker (IIl).

In this way, even if an excessive input signal is supplied to the tweeter (5), the cutoff frequency of the tweeter (5) is essentially shifted to the higher frequency side, so that a good signal can be produced without any interruption in the sound. You can get playback sound.

FIG. 5 shows another embodiment of the present invention, and FIG.
Although ordinary ferrite is used as the core member (4a), certain parts of it, such as the shaded part (4a1) in the same figure,
This is a case where a temperature-dependent μ member with a low cue point is used and the coil (4b) is wound intensively around this part. On the other hand, in FIG. 5B, a ring-shaped core member (4a') made of ordinary ferrite is used.
), for example, the shaded part (4ax') in the same figure.
In this case, a temperature-dependent μ member with a low Curie point is used as described above, and a coil (4b) is wound around this part. This makes it possible to obtain an inductor with even better temperature dependence.

As described above, according to the present invention, an inductor having a large temperature dependence is used as a component of the network of a speaker system, and the frequency characteristics of the filter in which the inductor is used are shifted due to excessive input heat that causes destruction. 5iCL, it is possible to protect the speaker system from excessive input signals without causing any interruptions in the reproduced sound, and there is no problem even when playing digital audio sources with a wide dynamic range. Since it uses the Curie point of the material, there is very little temperature hysteresis, and the point that changes is also very small.

In addition, in the above-mentioned embodiment, the tweet in the speaker system,
- Although we have discussed how to prevent damage due to excessive input in the evening, the present invention is not limited to this and cannot be similarly applied to other speakers that are at risk of being destroyed.

Further, in the above embodiment, the case where the filter characteristic of the tweeter is shifted to a higher frequency side when an excessive input signal is supplied has been explained, but it is also possible to continuously cut off the high frequency range of the filter characteristic of the tweeter. .

[Brief explanation of drawings]

FIG. 1 is a diagram for comparing and explaining LPD and DAD, FIG. 2 is a circuit configuration diagram showing an embodiment of the present invention, and FIG.
The figure is a perspective view for explaining the main part of this explanation.
The figure is a characteristic diagram for explaining the operation of FIG. 2, and FIG. 5 is a front view showing another embodiment of the present invention. (2) is a no-pass filter, (4) is an inductor,
(5) is a tweeter, (6) is a bandpass filter,
(11) is a squawker, θ2 is a low-pass filter, a is Uno, (1e is a heat insulating member. Figure 1 Figure 2 Figure 4 Figure 5 Factor

Claims (1)

[Claims] A speaker system characterized in that a temperature-dependent inductor having a predetermined Curie point is provided in a network of the speaker system, and filter characteristics of the network are changed when the Curie point is reached due to heat generation of the inductor.