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High-energy impulsive noise assessment

1986; Acoustical Society of America; Volume: 79; Issue: 1 Linguagem: Inglês

10.1121/1.393646

1520-9024

Paul D. Schomer,

Acoustic Wave Phenomena Research

In 1977 and again in 1981, the National Research Council (NRC) concluded that the C-weighted Day–Night Level was the best available measure with which to assess community response to high-energy impulse noise. Rattles in homes were the major adverse factor indicated by sonic boom and blast noise studies and cited by the NRC reports. Studies, since 1981, by the U. S. Army further support the NRC conclusions. Despite this wide consensus, there remain advocates for using only the A-weighting for measuring noise in the community—including that from high-energy impulses. This letter covers issues not considered in the NRC reports and provides additional rationale for the use of C-weighting, based on measurability and mitigation implications. This letter shows that impulsive noise is commonly hidden in other neighborhood sources when using A-weighting, but only rarely hidden when using C-weighting. There is a 10-dB improvement in signal to noise when using C-weighting. Also, A-weighting can mislead the public since it implies large benefits (up to 15 dB) for mitigation techniques such as barriers or forests. Low-frequency impulse energy, which rattles houses, is not attenuated by barriers or forests. Thus no large benefit is gained. C-weighting predicts the correct answer—only a few decibels of attenuation.