JPS639679B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to the improvement of audio equipment, and in particular aims to obtain audio equipment with high fidelity reproduction by improving the chassis, exterior panels, exterior cases of used electronic components, etc. (hereinafter referred to as exterior members in the main text) of the audio equipment. shall be. In recent years, the quality of reproduced sound in audio equipment has increased in fidelity, and various improvements have been made. Traditionally, improvements in audio equipment focused on improving the circuit configuration and active elements, but recently, various improvements have been made in addition to passive elements, connection wires, terminals, etc. as they have been found to affect sound quality. being done. Among such improvements, there is an improvement in the exterior member. Most conventional exterior members were made of iron. This is because it is easy to process, inexpensive, and has sufficient strength. However, since iron is a magnetic material, lines of magnetic force generated from electric current flowing through electronic components or wiring wires used in sound quality equipment propagate through the exterior members and leak magnetic lines of force to various places inside the equipment, and these leaked lines of magnetic force leak to other parts of the equipment. This causes current to be induced in the electronic components or wiring wires, resulting in the addition of unnecessary current other than the audio signal that is originally flowing, which prevents faithful audio signal transmission. This unnecessary addition of current is at an extremely low level, and it is currently difficult to grasp the quantitative difference using a measuring instrument, but it appears as a non-negligible difference in sound quality when compared by hearing. It is known that audio equipment in which as much of the exterior material made of magnetic material as possible is removed exhibits excellent sound quality characteristics. In order to eliminate the adverse effects of this exterior material, it has been considered that the exterior material is made of non-magnetic aluminum material. However, although audio equipment using aluminum materials exhibits superior sound quality characteristics compared to those using iron materials, the sound quality is inferior to those from which exterior members are removed. This is thought to be because the conventionally used aluminum material is relatively high-purity aluminum, which tends to generate eddy currents when lines of magnetic force penetrate through it, and the lines of magnetic force caused by eddy currents add unnecessary current. In addition, it has been considered to use plastics for exterior members, but although plastics do not generate eddy currents and have excellent sound quality characteristics, they have low mechanical strength and are difficult to apply to large exterior members, It has disadvantages such as poor conductivity and cannot be used as a heat sink or chassis for heat dissipation, and it is more expensive than metal members. The present invention focuses on the fact that an aluminum material, which is made by adding a certain substance to aluminum, suppresses the generation of eddy currents and improves acoustic characteristics, and is characterized by using the above aluminum material for the exterior member of an audio device. It is something to do. As for the aluminum material that meets the purpose of the present invention, as a result of making trial aluminum materials to which various substances were added and comparing the sound quality by using them as exterior members of audio equipment, it was found that carbon powder and silica (silicon dioxide) powder were found to be suitable for the purpose of the present invention. It was found that it was suitable as an additive substance. The reason for this is unclear, but both substances are nonconductors or have high electrical resistance, and when dispersed in powder form into molten aluminum, they are uniformly dispersed, making it difficult for eddy currents to flow, and preventing eddy currents from flowing. This is thought to be because the generation of magnetic lines of force is suppressed. FIG. 1 shows an embodiment of the present invention, in which an audio amplifier 1 includes a chassis 2, a front exterior panel 3, a top side exterior panel 4, a heat sink 5, and an exterior case for a power transformer 6.
This is an audio device using an aluminum material to which one or both of the aforementioned carbon powder and silica powder is added to exterior members such as the exterior case of the power supply capacitor 7 in addition to inevitable impurities. Furthermore, the aluminum material of the present invention is applicable not only to the audio amplifier of this embodiment, but also to arm of record players, turntables, exterior members of tape recorders, exterior materials of parts such as resistors and capacitors used in audio equipment, switches, etc. It can also be applied to mechanical parts such as terminals and connectors. Next, measurement of the effect of the present invention will be described. Judging the effectiveness is difficult because it is difficult to quantitatively understand it using measuring instruments.
A variety of musical tones were played using a sound device and a comparative listening test was conducted based on the auditory sensation. The listening method involved removing as much of the exterior material made of iron or other material as possible from the playback device, and placing plates made of various aluminum materials on both sides of the preamplifier circuit board in place of the exterior panels to examine differences in sound quality. The standard sound quality was the one without the metal plate, and the differences were expressed by relative comparison to this. The evaluation criteria were as shown in the table below, and the evaluation values were scored by the listeners.

[Table] Figure 2 is a graph of the evaluation results. In order to reduce the influence of personal habits, the evaluators were made up of five people, and the average was taken. In addition, to prevent preconceived notions, the listeners were not informed of the type of aluminum alloy in advance. Three types of musical tones were used: (A) symphony, (B) chamber music, and (C) vocal.
Then, the average value and standard deviation value range of the evaluation results are
Shown in the figure. As is clear from this result, when the iron plate mentioned as the conventional example is arranged, the sound quality is clearly inferior to that of the reference sound. Also, it can be seen that the sound quality of the device with high-purity aluminum plates is improved compared to the iron plate, but it is inferior to the device without any plate. On the other hand, those in which the aluminum material of the present invention is arranged, that is, those in which carbon powder is added in Examples (1) and (2) of the present invention, those in which silica powder is added in (3) and (4), and those in (5) are Both carbon and silica were added, and the sound quality was comparable to the standard sound quality, or in fact, depending on the type of musical sound, better sound quality characteristics were obtained. Regarding the amount of carbon and silica added,
As in the example of the present invention, there was almost no change in the sound quality characteristics due to the increase or decrease in the amount of additive, but as the amount added increases, the additive precipitates on the surface of the aluminum material, so it is necessary to remove it. Furthermore, if the amount added is extremely increased, the strength of the aluminum material will decrease, making it unsuitable for supporting heavy objects such as chassis. As described above, the audio equipment using the aluminum material of the present invention for the exterior member is hardly affected by the adverse effects of the generation of magnetic lines of force due to eddy currents, and can obtain excellent sound quality characteristics. Furthermore, it does not have the disadvantages of plastic materials such as lack of mechanical strength and difficulty in heat dissipation, and is easy to process like conventional steel materials, making it particularly suitable as an exterior material for audio equipment aiming for high fidelity. It is something that

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an audio amplifier showing an embodiment of the present invention, and FIG. 2 is a graph showing sound quality evaluation results. 1... Audio amplifier, 2... Chassis, 3,4
...Exterior panel, 5...Heat sink, 6, 7...Exterior case.

Claims (1)

[Scope of Claims] 1. An audio device characterized in that the exterior member is made of an aluminum material to which one or both of carbon powder and silica powder is added in addition to inevitable impurities. 2. The audio device according to claim 1, wherein the exterior member is a chassis of an audio amplifier. 3. The audio equipment according to claim 1, wherein the exterior member is an exterior panel of an audio amplifier. 4. The audio device according to claim 1, wherein the exterior member is an exterior case for an electronic component used in an audio amplifier. 5. The audio equipment according to claim 1, wherein the exterior member is a heat sink of an audio amplifier.