Handbook for Sound Engineers

576 Chapter 16

16.12.2 Windscreens and Pop Filters

A windscreen is a device placed over the exterior of a
microphone for the purpose of reducing the effects of
breath noise and wind noise when recording out of
doors or when panning or gunning a microphone. A
windscreen’s effectiveness increases with its surface
area and the surface characteristics. By creating innu-
merable miniature turbulences and averaging them over
a large area, the sum approaches zero disturbance. It
follows that no gain is derived from placing a small
foam screen inside a larger blimp type, Fig. 16-161A,
whereas a furry cover can bring 20 dB improvement,
Fig. 16-161B. Most microphones made today have an
integral windscreen/pop filter built in. In very windy
conditions, these may not be enough; therefore, an
external windscreen must be used.

With a properly designed windscreen, a reduction of
20–30 dB in wind noise can be expected, depending on
the SPL at the time, wind velocity, and the frequency of
the sound pickup. Windscreens may be used with any
type microphone because they vary in their size and
shape. Fig. 16-162 shows a windscreen produced by
Shure employing a special type polyurethane foam. This
material has little effect on the high-frequency response
of the microphone because of its porous nature. Stan-
dard styrofoam is not satisfactory for windscreen
construction because of its homogeneous nature.
A cross-sectional view of a windscreen employing a
wire frame covered with nylon crepe for mounting on a
1 inch diameter microphone is shown in Fig. 16-163.
The effectiveness of this screen as measured by Dr. V.
Brüel of Brüel and Kjaer is given in Fig. 16-164.

16.12.2.1 Wind Noise Reduction Figures for Rycote

Windshielding Devices

Rycote has developed its own technique for measuring

wind noise that uses real wind and a real time differen-

tial comparison. The technique compares the behavior

of two microphones under identical conditions, one

with a particular wind noise reduction device fitted and

the other without, and produces a statistical curve of the

result corrected for response and gain variations.

Fig. 16-165 is a Sennheiser MKH60 microphone—a

representative short rifle microphone—without any low-

frequency attenuation in a wideband (20 Hz–20 kHz)

test rig.

When a wind noise reduction device is fitted, its

effect on the audio response is a constant factor—if it

causes some loss of high frequency, it will do it at all

times. However, the amount it reduces wind noise

depends on how hard the wind is blowing. If there is a

flat calm it will have no beneficial effect and the result

will be a degradation of the audio performance of the

Figure 16-161. Blimp-type windscreen for an interference
tube microphone. Courtesy Sennheiser Electronic
Corporation.

A. Blimp-type windscreen.

B. Furry cover to surround the windscreen in A.

Figure 16-162. Shure A81G polyurethane windscreen.

Courtesy Shure Incorporated.

Figure 16-163. Typical silk-covered windscreen and micro-

phone. Courtesy B and K Technical Review.

Two layers nylon crepe

2/60.25 meshes PSI

Spherical wire

frame 120-mm

radius B&K UA 0082

B&K model

4131 microphone

(1 inch diameter)