JPH09271087A - Microphone supporting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microphone supporting device suitable for measuring noise at a position subjected to hard vibration, dust, air flows, rain, etc., such as a portion under car floor and capable of sampling acoustically accurate data. SOLUTION: The microphone supporting device 1 includes a frame 3 for supporting a microphone 7 in its inside. A microphone holder 5 and a string 21 for suspending and fixing the holder 5 are included in the frame 3. The outer surface of the frame 3 is covered with a net 13. Since the string 21 connecting the frame 3 to the holder 5 acts as a vibration preventing member, vibration applied to the frame 3 is not almost transmitted up to the microphone 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for supporting a microphone for noise measurement or the like. In particular, the present invention relates to a microphone support device suitable for performing noise measurement in a portion such as an underfloor of a vehicle that is subject to severe vibration, dust, air flow, rainwater, and the like.

[0002]

2. Description of the Related Art An underfloor noise in a railway vehicle will be described as an example. In recent years, the noise problem of railway vehicles has become more delicate. Especially,
When speeding up vehicles, expanding operating hours, increasing the number of trains, and introducing new vehicles, there are often complaints and requests for improvement regarding noise from residents along the line.

The typical noise emitted by railway vehicles is
Aerodynamic noise, which is the sound of the car body or pantograph cutting the wind, wheel rolling noise that is emitted when wheels roll on rails, and device noise that is emitted from in-vehicle devices (motor, drive device, brake, air conditioner, compressor, etc.). The underfloor noise includes rolling noise and equipment noise among them. Recently, as mentioned above, the noise problem has become delicate, so it is necessary to collect acoustically more rigorous data on underfloor noise. For example, there is also a demand for individually squeaking noise between wheels and rails in a curve, squeaking noise during braking, gear noise of a drive device, operation noise of a motor fan or a compressor, and the like.

In the conventional underfloor noise measurement, a microphone is held on an all-weather screen (manufactured by Rion Co.), and the microphone holder is directly fixed to a pipe or the like under the vehicle floor. In this case, the vibration of the pipe or the like (vibration of the vehicle body) is also applied to the sound sensing portion of the microphone via the microphone holder, so that the noise accompanying the vibration is mixed in the measurement signal of the microphone. When the data thus measured is reproduced, the original acoustic component is masked by noise, and it is impossible to obtain strict acoustic data. Further, since the all-weather screen has a spherical shape and a large diameter, it is difficult to mount it.

An example of such a situation will be shown as a test example. FIG. 3 is a diagram showing an outline of a test apparatus for testing the effect of noise due to vibration on a sound level meter (microphone). The sound level meter 65 to be tested is a shaker 67 of a shaker 69.
Is placed on top. The microphone diaphragm of the sound level meter 65 is in the vertical direction in the figure. The vibrating table 67 vibrates up and down. The microphone 61 of the standard sound level meter placed on the tripod 63 next to the vibrator 69 is for measuring background noise near the microphone 65 of the test sound level meter.

FIG. 4 shows the result of measurement as shown in FIG. FIG. 4 is a graph showing the power spectrum of the sound pressure level measured by the sound level meter in the test of FIG.
The solid line shows the reading of the test sound level meter, and the broken line shows the reading of the reference sound level meter. As shown in this figure, the measurement result of the sound level meter vibrating at the vibration acceleration of 9.8 m / sec ² is several tens of dB higher than that of the standard sound level meter (background noise). This is noise caused by vibration. With this, a meaningful noise measurement result cannot be obtained at all.

The present invention is to provide a microphone supporting device which is suitable for measuring noise in a portion such as an underfloor of a vehicle accompanied by severe vibration, dust, air flow, rainwater, etc., and which can collect acoustically exact data. With the goal.

[0008]

In order to solve the above-mentioned problems, a microphone supporting device of the present invention comprises a frame defining a microphone supporting region inside, a microphone holder located in the microphone supporting region, a frame and a microphone. A string for connecting the holder and suspending and fixing the microphone holder. The string connecting the frame and the microphone holder plays a role of anti-vibration, and even if the frame is vibrated, the vibration is hardly transmitted to the microphone. Therefore, it is possible to collect strict acoustic data in which noise resulting from vibration of the microphone is not mixed. Note that, here, “fixing the microphone holder by hanging it with a string” means that the string is moved in each direction in a state where there is almost no slack in the string and the microphone holder is not shaken so much.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The microphone support device of the present invention preferably comprises a net covering the outer surface of the frame. Here, it is preferable that the mesh is a metal mesh having a certain strength and a mesh having fine meshes (1100 mesh or less, 0.3 mm square or less) (such as synthetic fiber-clad nylon mesh). Reduce the velocity of the airflow hitting the microphone,
This is because the wind noise of the microphone can be reduced, and it can also be used as a waterproof / dustproof measure.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a perspective view showing a microphone support device according to an embodiment of the present invention. FIG. 2 is an enlarged perspective view showing a microphone holder of the microphone support device of FIG.

The microphone support device 1 of this embodiment is
The frame 3 has a rectangular parallelepiped outer shape. This frame 3
A mesh 13 is provided on the outer surface of the sheet except for the front side of the figure. Note that the front surface of the figure also becomes a meshed surface if the meshed opening window 31 is closed. The frame 3 with the net 13 has a shape just like a small bird cage, has a shape and size that can be easily attached to a pipe or the like, and has a hook for attachment on the outside. Have In the example of this figure, the dimensions of the frame 3 are 20 cm x 20 cm.
× 30 cm.

A microphone holder 5 is provided at the center of the frame 3.
And the microphone 7 is suspended. In other words, the microphone holder 5 is located at the top, bottom, back,
It is hung by the four straps 21 in the front, and is also hung by the four straps 21 from the right hand direction. This string 2
1 is a wire tape for electrical insulation (width 25 mm, thickness 0.2
5 mm). I tried various straps, but this tape was the best. It seems that a tape with a flat cross section and elasticity of the same level is suitable. The frame side end of the string 21 is tied to the hook 15 provided at the center of the left side 11 and the center side 17 of the frame 3.

Details of the microphone holder 5 will be described with reference to FIG. The holder main body 41 of the microphone holder 5 has an upper and lower split structure. Upper and lower holder body 41a
And 41b have a shape in which blade-shaped flange portions 43 are projected to both sides (back and front) of the central half-split cylindrical portion 42. Such an upper holder body 41a and a lower holder body 41
b and the two half-cylindrical portions 42 face each other so as to form one pipe. A plate of foamed rubber 55 is fitted into a central hole 54 formed by both half-cylindrical portions 42.
The foam rubber 55 is also divided into upper and lower parts.

In order to connect the upper and lower holder bodies 41, a screw 51 and a wing nut 53 are provided at the center of the flange portion 43.
, But two sets are provided on the back side and the front side. The microphone 7 (FIG. 1) can be attached by sandwiching the handle of the microphone between the foamed rubber 55 of the hole 54 and tightening the wing nut 53. At this time, the foamed rubber adjusts the size according to the size of the microphone, and plays a role of some vibration isolation.

Ring-shaped hooks 45 are attached to the four corners of the lower holder body 41b. In addition, the upper and lower holder main body 41 has a half-cylindrical portion 42 above and below which extends in the left-right
A model-shaped large hook 47 is attached. The above-mentioned string 21 (FIG. 1) is tied to these hooks.
In order to fix the microphone holder 5 in a predetermined position and posture, it is necessary to tie the left and right ends of the microphone holder 5 in a state of being stretched in three directions with at least three strings.

Referring back to FIG. Microphone 7
A wind screen 9 is attached to the tip (right end) of the. The windscreen 9 is made of open cell urethane foam (attached to the end of a karaoke microphone). The wind screen 9 plays a role of reducing wind noise. Rear end of microphone 7 (left end)
A cable 29 comes out from. The cable 29 is led out from the hole of the cable passage 27 provided on the upper surface of the frame 3.

The mesh attached to the frame 3 comprises a stainless wire mesh with a hole (hexagonal hole) size of about 1 cm and a double synthetic nylon cloth (mesh size about 1100, mesh size 0.3 mm square). It is a stack. With wire mesh to provide strength and protection against flying objects such as pebbles,
Nylon mesh reduces wind noise, drip-proof, and stain-proof.

When the underfloor noise of a railway vehicle at a maximum speed of 425 km / hr was measured with the microphone supporting device of this embodiment, good noise data, which was judged to be almost unaffected by vehicle body vibration, could be obtained. .

[0019]

As is apparent from the above description, in the microphone supporting device of the present invention, the string connecting the frame and the microphone holder plays the role of vibration proof, so that even if the frame is vibrated The vibration is hardly transmitted. Therefore, it is possible to collect strict acoustic data in which noise resulting from vibration of the microphone is not mixed. Furthermore, when a net for covering the outer surface of the frame is provided, the velocity of the air current impinging on the microphone can be reduced, wind noise of the microphone can be reduced, and waterproof and dustproof effects can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a microphone support device according to an embodiment of the present invention.

2 is an enlarged perspective view showing a microphone holder of the microphone support device of FIG. 1. FIG.

FIG. 3 is a diagram showing an outline of a test apparatus for testing the influence of vibration noise on a sound level meter (microphone).

FIG. 4 is a graph showing a power spectrum of a sound pressure level measured by a sound level meter in the test of FIG. The solid line shows the reading of the test sound level meter, and the broken line shows the reading of the reference sound level meter.

[Explanation of symbols]

 1 Microphone Support Device 3 Frame 5 Microphone Holder 7 Microphone 9 Windscreen 11 Left Side 13 Mesh 15 Hook 16 Long Side 17 Center Side 19 Right Side 21 String 27 Cable Thread 29 Cable 31 Open Window 41 Holder Body 42 Half Cylindrical Section 43 Flange 45 Hook 47 Large hook 51 Screw 53 Wing nut 54 Hole 55 Foam rubber 61 Standard sound level microphone 63 Tripod 65 Test sound level microphone 67 Excitation stand 69 Exciter

Front Page Continuation (72) Inventor Akira Sagawa 38-8 Mitsumachi, Kokubunji, Tokyo 38 Inside the Railway Technical Research Institute

Claims (2)

[Claims] 1. A microphone comprising: a frame defining a microphone supporting region inside; a microphone holder located in the microphone supporting region; and a string for connecting the frame and the microphone holder and suspending and fixing the microphone holder. Support device. 2. A microphone supporting device further comprising a net covering the outer surface of the frame.