Those who know me know that I tend to take an academic
viewpoint on these things. I did a quick check of
what has been published in the Journal of the Audio
Engineering Society, and found a couple of helpful
papers:
"Microphones and Wind", Wuttke, Jorg; JAES, vol. 40,
No. 10, 1992 October
"Windnoise Meausrement using Real Wind"; Woolf, C,
Prudden, O., AES preprint 5269, 109th Convention of
the AES
Jorg Wuttke is chief engineer of Schoeps. I'll try to
give a brief synopsis of his paper here:
Pressure microphones and pressure gradient microphones
have different sensitivity to wind noise.
Measurements presented at a wind speed of 18 kph for
the Schoeps MK-2 (omni) and MK-41 (cardioid) show
about 20 dB greater noise at low frequencies for the
cardioid. The difference diminishes to about 10 dB at
500 Hz. There is still significant wind noise at 1
kHz.
Both basket-type and foam windscreens can be
effective. Foam windscreens tend to merely attenuate
the highest frequencies (about 2 dB in the top octave
for the one evaluated in this paper) whereas the
basket type has less overall attenuation but
introduces narrow-band peaks and dips amounting to
about 10 dB peak-peak.
The basket type windscreen is more effective at low
frequencies, but less effective at mid and high
frequencies than the foam windscreen.
Quote "
Conclusions
Foam windscreens should be used wherever the
protection they offer is sufficient, for their
negative effect on the sound is relatively small and
easily correctible. On pressure transducers they are
almost always the best choice.
Basket-style windscreens must be used on directional
microphones if foam types are inadequate to reduce the
levels of wind interference. They do detract from the
sound and directivity of a pressure-gradient
transducer to the degree that they are small and
efficient. A good compromise between the two types is
a hollow foam windscreen. In all cases care must be
taken to avoid overloading the microphone channel's
input electronics due to the excessive very low and
even infrasonic frequencies produced by the action of
wind on the microphone diaphragm. Attenuating the
system's low-end response at the earliest opportunity
is always a good idea to ensure a clean transmission.
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end quote
Now, if you don't happen to agree with this, don't
shoot me. I'm only the messenger.
eric
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