Evaluations of the Annoyance Effects of Noise

Abstract

Noise is defined as audible sound that disrupts silence and causes annoyance. Such annoyance is traditionally assessed by the A-weighted sound pressure level of noise, roughly corresponding to the level of perceived loudness. However, the A-weighted scale is inapplicable for analyzing tonal, pulsed, and predominantly low-frequency noise; therefore, methods have been developed for calculating noise loudness in linear units, sones, which take into account not only auditory sensitivity, but also masking properties and auditory temporal effects. The existence of noise reduction limits and their informational significance have led to other methods for assessing noise annoyance. Annoyance, in addition to loudness, is caused by such subjective noise qualities as sharpness, roughness, fluctuation strength, tonality, etc. Units of measurements have been defined for these and calculation methods developed. Taking such qualities into account, a metric of short-term psychoacoustic annoyance (PAA) has been proposed, which is valid for many types of noise. Another method for evaluating PAA includes conducting an auditory examination and constructing a mathematical model that relates the rank of auditory annoyance to the measured subjective qualities of the noise. The resulting model helps to identify the causes of annoyance (subjective annoying qualities); develop work plans aimed at noise suppression, the formation of pleasant noise by machines and mechanisms; and control changes in the rank of annoyance in the implementation of such plans. This paper compares different methods for assessing the annoyance caused by noise recorded in Moscow subway cars.