JPS6314559Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a directional dynamic microphone, in which a single resistor material serves as both the acoustic resistance for the phase shift circuit and the acoustic resistance for the rear air chamber, and provides stable performance at a low price. The purpose is to obtain a directional dynamic microphone.

Figure 1 shows a side cross section of a conventional directional dynamic microphone, in which 1 is a magnetic yoke, 2 is a diaphragm attached to a part of the magnetic yoke 1, and 3 is a diaphragm 2 attached to a voice coil. , 4 is a magnet, 5 is a holding member for fixing the position of the magnet 4, 6 is a rear case, 6a is a rear air chamber formed by the rear case 6 and the magnetic yoke 1, 7 is an acoustic resistance material for the rear air chamber, 8 is a phase shift circuit acoustic terminal provided on a part of the magnetic yoke 1; 9 is an acoustic resistance material for the phase shift circuit pasted on the phase shift circuit acoustic terminal 8; In order to guide the sound waves to the back surface of the plate 2 and obtain directivity, an acoustic resistance material 9 for the phase shift circuit is placed on the phase shift circuit acoustic terminal 8 provided on a part of the magnetic yoke 1 in order to control the directivity. A pasting method is commonly used. Conventionally, the acoustic resistance material 9 for the phase shift circuit is in the form of a tape to be wrapped around the outer circumference of the magnetic yoke 1, but the winding process is time-consuming and at the same time it is very difficult to apply it uniformly, resulting in poor performance. The drawback was that it became unstable.

The present invention eliminates the above-mentioned drawbacks of the conventional technology, and an embodiment of the present invention will be described below with reference to FIG. In the figure, 10 is a magnetic yoke, 11 is a magnetic pole piece, 12 is a magnet, 13 is a synthetic resin case in which the magnetic yoke 10 is molded, 14 is a diaphragm attached to a part of the synthetic resin case 13, and 15 is attached to the diaphragm. 16 is a rear case, 16a is a rear air chamber provided in the rear case 16, 17 is a phase shift circuit acoustic terminal provided on the outer periphery of the rear case 16, and 18 is an acoustic resistance material.

In this case, the sound waves guided from the phase shift circuit acoustic terminal 17 pass through the outer peripheral part 18a of the acoustic resistance material 18 and reach the back surface of the diaphragm 14, and the central part 18b of the acoustic resistance material 18 is different from the conventional structure. It serves as the acoustic resistance material 7 for the rear air chamber, and one acoustic resistance material 18 provides a directional dynamic microphone.

The outer edge 18c of the acoustic resistance material 18 is fixed to the synthetic resin case 13 with adhesive or the like, eliminating the need for unstable work such as wrapping, and obtaining a directional dynamic microphone with stable performance at a low price. be able to.

As described above, the present invention uses both the acoustic material for the rear air chamber and the acoustic resistance material for the phase shift circuit, so that it is possible to obtain a directional dynamic microphone that has a simple structure and is easy to manufacture.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a conventional directional dynamic microphone, and FIG. 2 is a side sectional view of a directional dynamic microphone according to an embodiment of the present invention. 10...Magnetic yoke, 11...Magnetic pole piece, 12...
... Magnet, 13 ... Synthetic resin case, 14 ... Diaphragm, 15 ... Voice coil, 16 ... Rear case, 16a ... Rear air chamber, 17 ... Phase shift circuit acoustic terminal, 18 ... Acoustic resistance material .

Claims (1)

[Scope of utility model registration request] A directional dynamo characterized by having a diaphragm fixed to a voice coil supported in a magnetic field by a magnetic circuit, and incorporating a resistance material that serves as an acoustic resistance for the phase shift circuit and an acoustic resistance for the rear air chamber. Mitsuku microphone.