Everyone has heard the loud sound wind makes on a cellphone used outdoors. Even when measuring sound indoors, if near an open window or door, air blows in because of the "chimney effect" in buildings. Use of a windscreen is standard professional practice to prevent this wind noise, which can dramatically affect the reading at all frequencies.
In this consultant's testimony, he excuses his failure to use a windscreen by claiming to have used a "setting" on his meter instead. But the "windscreen" setting is merely intended to compensate for the slight reduction in high frequencies when a windscreen is used, as he himself alludes to. The "no windscreen" setting simply removes this compensation. Neither setting has anything to do with compensating for potential errors caused by air movement around the microphone without a windscreen. And in any case, low frequencies were the only issue here, frequencies which by his own testimony would not be affected by the "setting".
(W 1 [opposing consultant] — by Defendant — Direct (Rebuttal)/J. Mallin
QDid you use a wind screen when you did the testing on all --
A I did not use a wind screen.
QWhy didn't you?
AWe were inside. It was not windy out. I didn't have it on the meter that day.
QAre you able to do anything with your equipment to adjust for that?
AThe meters we use have wind screen adjustment on them. Meaning, you put it on and you turn the wind screen adjustment on.
QHow does that work?
AYou go in the meter and you turn it - that setting on. So you say yes there is a wind screen or no there is no wind screen on the meter.
QAnd what, if any, result does that have on the data?
AIt changes the high-frequency response of the meter. In this case, though, we were inside. It was not windy. And even if I didn't have a wind screen on and it was windy, the level would have been louder, it would have been blowing over the microphone.
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