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".