JPH05252583A - Protection device for electroacoustic transducer - Google Patents

Abstract

PURPOSE: To manufacture the device which has improved sound characteristics at low cost so that its appearance is inconspicuous by forming a protection body of particulate-sintered plastic. CONSTITUTION: A protection cap 14 operates to shield a microphone capsule 12 on an intermediate member insulating a solid propagated sound in a casing 11. The protection cap 14 uses a particulate starting raw material formed of a sintered particulate polyethylene material and has a smooth surface. This surface suppresses the generation of wind noise and is small in deposition area where dirt spoiling noise quality is deposited. The smooth surface is formed by selecting the specially particulate sintered material and also by a sintering process itself. Namely, particles are sintered as a result of slight melting of particle surfaces of the sintered material as the process advances, and the particle surfaces themselves become smooth. Further, reinforcement is achieved by molding press during the sintering process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective device for an electroacoustic transducer, in particular a protective body made of a sintered material, which at least partly surrounds the electroacoustic transducer. To a protection device for a microphone capsule.

[0002]

In order to protect electroacoustic transducers, in particular microphone capsules, it is known to enclose the microphone capsule with a protective cap made of a sintered metal material, for example sintered bronze. Protective caps made of sintered material, due to their high mechanical strength, provide good protection against breakage of the microphone capsule, but on the other hand have unsatisfactory acoustic properties and are very expensive to manufacture.

An unsatisfactory acoustic characteristic is that, for example, so-called pop noise is generated when a microphone is spoken very close to the mouth. Further known microphone protection caps tend to enhance wind noise due to the rough grained surface that is process constrained. These wind noises significantly degrade the recording quality achievable with this microphone. Furthermore, since the surface of known protective caps has the metallic appearance typical of microphones, in practice microphones with such protective caps often exhibit inconvenient features that can be distinguished from a distance. ..

[0004]

SUMMARY OF THE INVENTION It is an object of the invention to provide a protective device for an electroacoustic transducer which has improved acoustic properties and which can be manufactured inexpensively and inconspicuously. is there.

[0005]

The above-mentioned object is defined in claim 1.
Protection for a microphone capsule consisting of a protective body made of a sintered material (sintered material), which at least partly surrounds the electroacoustic transducer, in particular the electroacoustic transducer. In the device, a protector (14;
25, 26) is achieved by a protective device, characterized in that it consists of fine-grained sintered plastic.

[0006]

In the protective device according to the invention, the protective cap is made of fine-grained sintered plastic. Compared to metal, plastic has a much simpler sintering process and is cheaper to process. Furthermore, the fine plastic particles used as the raw material can be embedded in the outer area of the protective body sintered in a simple post-pressing process, so that the protective body has a smooth surface without flow resistance which is a prerequisite for wind noise generation. is doing.

The fine-grained sintered plastic has a porous open-cell structure. This structure allows air, and thus air sounds, to pass through, so that air sound waves can pass unimpeded through the enclosure. However, since the attenuation characteristic is far better than that of metal, solid-borne sound is considerably absorbed. Therefore, when a protective cap made by sintering fine-grained plastic is used, known pop noise does not occur.

Further, plastic is less expensive to manufacture by a sintering method than metal and is easy to mold.
It is also possible to color protective caps made from secondary processing or plastic. Therefore, the protective cap can be formed with an unobtrusive appearance in harmony with the surroundings. Since the protective cap made of plastic has no metallic appearance without any secondary processing, exposure of the protective cap is originally avoided.

As the plastic, polyethylene, which is an industrial plastic which has many uses and which can be easily processed, is used. Particularly good results with regard to improved acoustic properties compared to the use of metals are achieved by the synthesis of sintered materials consisting of polyethylene with variously tailored molecular properties. Ultra high molecular weight polyethylene, so-called UHMW
A mixture of a PE-based sintering material and a high-density polyethylene, so-called HDPE-based sintering material, is particularly suitable.

The improved protective properties of the protective cap are achieved by a hydrophobic treatment of the plastic material. This hydrophobic treatment is possible by adding graphite to the plastic before carrying out the sintering process. By this hydrophobic treatment, water impermeability is realized in polyethylene which is originally permeable to at least part of water vapor. Hydrophobic treatment is permanent because graphite chemically bonds with polyethylene when hydrophobically treating polyethylene. The sintered metal can also be subjected to a hydrophobic treatment, which is done by impregnating the sintered material with oil. This only results in an outer water repellent coating. It is not permanent and adversely affects the acoustic properties of the sintered material.

According to a first embodiment of the protective device according to the invention, the protective body is formed as a microphone capsule sleeve of a microphone. According to another embodiment, it is possible just as well to jointly make the entire casing for accommodating the microphone capsule from sintered plastic material, so that the protective body and the cable form the same member. Based on the good processing characteristics of sintered plastic materials,
With the exception of the microphone casing, as well as the microphone capsule, it is possible to make all the parts that are connected to the casing for assembling the microphone from a sintered plastic material.

[0012]

Embodiments of the protective device according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a handheld microphone 10 having a casing 11 for housing a microphone capsule 12. The casing 11 is formed of two parts, and includes a basic casing 13 and a protective cap 14 connected to the basic casing 13. The protective cap 14 functions to shield the microphone capsule 12 provided inside the casing 11 on the intermediate member 15 that insulates the solid propagation sound inside the casing 11. In order to mechanically and reliably connect the microphone capsule 12 to the basic casing 13, the plug portion 16 of the microphone capsule 12 is inserted into the holding portion 17 of the intermediate member 15. The intermediate member 15 itself is inserted into the holding portion 18 of the basic casing 13. In order to connect the protective cap 14 to the basic casing 13, the protective cap 14 is inserted in the step portion 19 of the basic casing 13.

The connection between the microphone capsule 12 and the amplifier, which is not shown in detail here, consists of conductors 20,2.
Through 1. The conductors 20, 21 are led out of the basic casing 13 as an insulated connection cable 22. The transition from the conductors 20, 21 to the connecting cable 22 takes place by means of a plug connection, not shown here in detail. This plug connection is secured by the cap nut 23 by means of a threaded portion of the basic casing 13, which is also not shown.

In accordance with the present invention, the protective cap 14 uses a very finely divided starting material of sintered finely divided polyethylene material so that the protective cap 14 has a generally smooth surface. This surface suppresses the generation of disturbing wind noise, as described above. Furthermore, since the surface is smooth, the deposition area where dirt that may impair the recording quality of the microphone capsule is deposited is small.

The smooth surface of the protective cap 14 is achieved, on the one hand, by selecting an extra-fine-grained sintering material as described above, and on the other hand, also promoted by the sintering process itself. As a result of light melting of the particle surface of the sintered material during the process, the particles are sintered and the particle surface itself becomes smooth. The surface smoothing is further enhanced by the molding press during the sintering process. Therefore, the protective cap 14 produced by the sintering method has a porous open cell structure that allows the passage of air acoustic waves and a smooth outer surface.

The smooth outer surface and properties of the protective cap 14 made of plastic contribute to the fact that the microphone provided with the protective cap of the present invention is significantly different in appearance from the known microphone provided with a protective cap made of sintered metal. To do. This allows the microphone to be camouflaged. Such a microphone can be mounted invisibly and thus prevent the microphone from being discovered and thus the possible vandalism.

FIG. 2 shows a microphone 24 as another embodiment of the present invention. The entire casing 25 is designed as a protective device according to the invention and consists of sintered polyethylene. Outside the casing 25, the casing insertion member 2
There is 6. The casing insertion member 26 is screwed into the screw hole 28 of the casing 25 by the casing step 27 and is made of sintered polyethylene.

In this embodiment, the cable insertion member 26
Is simultaneously formed as an intermediate member that insulates solid-borne sound. By doing so, the number of individual components required to form the microphone casing can be reduced overall. Similar to the embodiment shown in FIG. 1, the plug portion 16 of the microphone capsule 12 is inserted into the holding portion 29 of the casing insertion member 26 formed as an intermediate member. In the embodiment shown in FIG. 2, the plug connection of the connection cable 22 is made in the area of the plug 16 by the plug connection of the conductors 20, 21 not shown here in detail.

The embodiment of the protective device according to the invention shown in FIG. 2 is possible due to the high mechanical strength and the good processability of the sintered polyethylene. In this example, it is noted that the specific gravity of the sintered material is particularly small. As a result, the microphone 24 can be formed to be extremely lightweight, thus improving the ease of handling. Furthermore, since it can be formed in various ways by using polyethylene, the microphone 2
4 can be given an arbitrary appearance, thus allowing camouflage and especially aesthetic formation.

[0021]

According to the present invention, the protective cap is made of sintered finely divided polyethylene material and has a generally smooth surface. Therefore, as described above, it has the effects of suppressing the generation of disturbing wind noise and of reducing the area of sedimentation of dirt that may impair the recording quality of the microphone capsule.

Further, according to the present invention, there is an effect that it has a protective cap manufactured by a sintering method and a porous continuous foaming structure that allows the passage of air sound waves.

Still further in accordance with the invention, the appearance of the microphone with the protective cap of the invention made of plastic is significantly different from the microphone with a protective cap made of known sintered metal, thereby camouflaging the microphone. Since it can be installed, it can be installed invisibly, and it has the effect of preventing the discovery of the microphone and thus possible vandalism.

Furthermore, according to the present invention, a sintered material having a particularly low specific gravity is used, and as a result, the microphone can be formed to be extremely lightweight, and thus the handleability is improved. Furthermore, the use of polyethylene allows it to be formed in various ways, giving the microphone an arbitrary appearance and thus camouflage and especially aesthetic formation.

[Brief description of drawings]

1 is a cross-sectional view of a microphone having a protective device formed as a protective cap according to the present invention.

FIG. 2 is a sectional view of a microphone having a casing formed entirely as a protective device.

[Explanation of symbols]

 10 Hand Microphone 11 Casing 12 Microphone Capsule 13 Basic Casing 14 Protective Cap 15 Intermediate Member 16 Stopper 17 Holding Part 18 Holding Part 19 Steps 20, 21 Conductor 23 Cap Nut 24 Microphone 25 Casing 26 Casing Insertion Member 27 Casing Step 28 28 Screw Hole 29 plug

Claims (6)

[Claims] 1. A protective device for a microphone capsule comprising an electroacoustic transducer, in particular a protective body made of a sintered material (sintered material), which at least partly surrounds the electroacoustic transducer, Protective body (14; 25, 26)
Is a fine-grained sintered plastic protective device. 2. The protective device for an electroacoustic transducer according to claim 1, wherein the plastic of the fine-grained crystalline plastic is polyurethane (PE). 3. The polyurethane used in the fine-grained sintered plastic is at least two polyethylene components, preferably UHMWP, with variously adjusted molecular properties.
The protective device protection device for an electroacoustic transducer according to claim 2, characterized in that it is synthesized from E, ie ultra-high molecular weight polyethylene, and HDPE, ie high-density polyethylene. 4. Protection for an electroacoustic transducer according to claim 1, characterized in that an additive, preferably graphite, is added to the polyethylene used for the fine grain sintering. apparatus. 5. The electroacoustic transducer according to claim 1, wherein the protective body is formed as a microphone capsule sleeve (protective cap 14) of the microphone (10). Protective device for. 6. A plurality of protective bodies (2) which jointly form a casing for housing the microphone capsule (12).
5. 26) Protective device for an electroacoustic transducer according to any one of claims 1 to 5, characterized in that it is formed by