Psychological evaluation of temporally varying sounds with L_Aeq and noise criteria in Japan

Abstract

The authors started the study of the impression of temporally varying sounds in 1960’s by developing the equipment to generated tempoally varying sounds.Since then many psychological experiments have been conducted and it was found that L_Aeq shows good correspondence with subjective impressions.In Japan in September 1998, Environmental Quality Standard for Noise was revised adopting L_Aeq as a noise measure.It is true that L_Aeq has many advantages and is a good measure of various noises.However, when it is adopted to determine a criteria of various kinds of noise and to predict subjective impressions of noises, there are some problems to be considered.They are, for example, (1)validity of A-weighting when sounds have prominent frequency components, (2)effect of qualitative aspects of sounds, and(3)effect of cognitive aspects of sound sources.These topics are discussed on the basis of the experimental data.