JPS6130800B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microphone equipped with a shock noise canceller.

For example, moving coil microphones are widely used because they are small, sensitive, relatively durable, easy to handle, and inexpensive; however, the inertial mass of the voice coil is large. , the disadvantage is that it picks up a large amount of vibration transmitted to the microphone case, resulting in large disturbance noise.

As a means to eliminate these drawbacks, (a) the mass of the vibration system, especially the mass of the voice coil, should be made as small as possible;

(b) Support the micro unit by suspending it from the case with flexible rubber, etc.

(c) A method to cancel unnecessary force applied to the diaphragm due to pressure changes due to vibration in the rear air chamber of the unit.

However, the above method (a) has problems with the microphone sensitivity and the strength of the voice coil material, and the method (b) has problems with damping the mechanical resonance between the compliance of the support rubber and the mass of the unit. Furthermore, in method (c), the acoustic function and the cancel function of the unit are integrated, so the mechanism is limited and complicated, which are mutually exclusive disadvantages of each method. It was hot.

This invention was developed to eliminate all of the various problems and drawbacks mentioned above, and includes a vibration detection device that electrically detects external vibrations applied to the microphone body. The output is used to remove noise generated in the microphone unit due to external vibrations.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 shows a first embodiment according to the present invention.
is a cylindrical microphone case, inside which a microphone unit 2 is elastically supported coaxially via elastic support members 3, 3 made of rubber or the like.

Further, in the front part of the unit 2, a well-known electrodynamic microphone assembly A consisting of a magnet 4, a yoke 5, a diaphragm 7 with a voice coil 6, etc. is arranged. Next, a cancel coil 8 for canceling external vibrations is wound around the base of the structure A, and a magnet 9 is fixed to the inner surface of the case 1 facing the coil 8, so that the above-mentioned vibration detection device can be installed. Configure.

Then, the voice coil 6 and the cancel coil 8 are wired so as to be connected in opposite phases to each other with respect to external vibration, and the lead wire 1 from this wire connection portion 10 is connected.
1 to the primary side of the microphone transformer 12,
The secondary side of the transformer 12 is connected to terminal pins 14, 14 implanted in a shadow seat 13 provided at the bottom of the case 1. Note that 15 in the figure is a sound-permeable cap.

Since the microphone of the present invention has the above configuration, the sound waves reaching the diaphragm 7 cause the diaphragm 7 to
The voice coil 6 of the microphone vibrates and can be used normally as a microphone. That is, in this case, the cancel coil 8 does not vibrate due to the above-mentioned sound waves, and the microphone output can be extracted without any problem.

However, when unnecessary vibration is applied to the microphone case 1 from the outside, the microphone unit 2
Because of its inertia, it vibrates relative to the case 1 against the elasticity of the elastic support members 3, 3, so an electromotive force is generated in the coil 8 due to the disturbance vibration of the cancel coil 8 in the magnetic field of the magnet 9. .

On the other hand, since an electromotive force is also generated in the voice coil 6 of the diaphragm 7 due to external vibration, each coil is adjusted so that the phase of the electromotive force caused by the coil 8 and the phase of the electromotive force caused by the voice coil 6 are opposite to each other as described above. 6
and 8 are connected, it is possible to cancel out and eliminate only the noise component due to unnecessary external vibrations without impairing the acoustic characteristics of the microphone.

FIG. 2 shows a second embodiment of the present invention, in which a cancel coil is provided separately from the microphone unit. The cancel coil 8 is wound around a coil winding frame 16, and the coil winding frame 16 is elastically supported within the microphone case via an elastic support member 17. A magnet 9 is fixed to the inner surface of the case 1 facing the coil 8. has been done. Then, by connecting each coil to each other so that the electromotive force generated in the voice coil of the microphone unit and the electromotive force generated in the cancel coil due to external vibration are added with opposite phases to each other. The same functions and effects as in the first embodiment described above can be obtained.

It should be noted that the above-mentioned cancel coil 8 can also have a canceling effect on induced noise at the same time, and is therefore effective in removing hum.

Furthermore, although a moving coil type vibration detection device is used in the first and second embodiments, a moving magnet type vibration detection device may also be used.

In addition, since the relative speed of the microphone unit 2 to the case 1 is sufficiently larger than the speed of the diaphragm 7, the magnetic flux density required for the electromotive force of the cancel coil 8 is small, so it is possible to use an inexpensive ferrite magnet or a specially designed magnet. The magnetic field due to the leakage magnetic flux of the magnet 4 of the microphone unit 2 may be used without providing the magnet 4 of the microphone unit 2.

As described above, the present invention provides a vibration detection device within the microphone case that detects external vibrations applied to the microphone case, and converts the detection signal from the detection device into a noise signal output from the microphone unit due to the external vibration. Since the signal is added to the output signal of the microphone unit so that it is in the opposite phase to It is possible to collect clear sound.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram showing a first embodiment of the present invention, and FIG. 2 is a cross-sectional configuration diagram showing a second embodiment of the invention. Explanation of symbols, 1...Microphone case, 2...
...Microphone unit, 3...Elastic support member,
4...Magnet, 6...Voice coil, A...
Microphone component, 8... cancel coil.

Claims (1)

[Claims] 1. A vibration detection device that detects external vibrations applied to the microphone case is provided inside the microphone case, and the detection signal from the detection device is set to have a phase opposite to the noise signal output from the microphone unit due to external vibration. A microphone characterized in that the noise signal is added to an output signal of a microphone unit to remove the noise signal.