Desirable Road Traffic Noise for Human Hearing

This paper describes the desirable condition of road traffic noise for human hearing in terms of sound quality. In general, the reduction of the envelope fluctuation of the sound and the reduction of high frequency contents of the sound under consideration beyond 1 kHz are effective for realizing the desirable sound perception for machinery noise. This approach is also true for the environmental sound such as road traffic noise according to the result of our laboratory experiment from the view point of sound quality. At present, desirable sound environment is determined by the prescribed Laeq value, i.e., equivalent A-weighted sound pressure level. But from our experience, Even under the same Laeq values, our perception from various road traffic noise differ significantly because of the fact that their sound qualities are different within each other. This fact is examined in detail by laboratory experiment by utilizing the recorded real road traffic noise.