Assessment of community response to impulsive noise

The U.S. Army Construction Engineering Research Laboratory has completed community attitudinal surveys at two major Army installations. The main purpose of these surveys was to better understand community response to the impulsive noise generated by large Army weapons such as tanks, artillery, or demolition. The results show that an energy type of model such as the C-weighted day/night average sound level (CDNL) is the best available descriptor for community response for these types of impulsive sound. Growth in annoyance to all noises increases monotonically with both sound amplitude and frequency of occurrence. This descriptor should incorporate a nighttime adjustment on the order of 10 decibels (dB). The exact function for relating the percentage of a community highly annoyed to CDNL remains in question. It appears that the present National Academy of Science Committee on Hearing, Bioacoustics and Biomechanics (CHABA) recommendation may underestimate actual annoyance, and that the functional relation between annoyance and CDNL should be shifted by 3-4 dB. However, more research on the percentage of a community highly annoyed versus CDNL and the existence and value of community rise- and decay-time constants is required to clarify this issue.