Norms and limits for admissible noise, as specified in the law, are always stated in terms of physically measurable attributes and are often determined and applied with a precision of fractions of a decibel. Human perception and memory for sounds, however, are not so accurate to justify discussions about fractions of a dB. Differential sensitivity for sound intensity is, under ideal laboratory conditions, approximately one decibel. Under more realistic conditions differential thresholds are considerably higher. Noise intensity levels for which members of a test population indicate to be severely annoyed show a typical interquartile spread of about 20 dB. Correlation coefficients between reported annoyance and actually measured sound levels, as has been done in many professional survey studies, are typically around 0.3. This implies that only 9% of the variance in the annoyance ratings can be explained by the physical sound level. The great variance in perceptual annoyance data seems to a very large extent due to psychological, non-acoustic factors and only to a much smaller extent due to insufficient control of the acoustic measurements.
|Number of pages||8|
|Publication status||Published - 1998|