Scale model experiments on noise reduction by acoustic barrier of a straight line source

Noise reduction by an acoustic barrier of a straight line source is examined with the aid of scale model experiments. The line source used in these experiments is an incoherent line source mechanically radiating broad band noise. From the experimental results a curve can be deduced which shows a relation between sound attenuation and Fresnel number N. This curve shows values lower than those of Maekawa's data by 3 ～ 5 dB, which are presented for a point source. On the other hand, it agrees fairly well with Rathe's experimental results, measured near the tracks of a railway line, and also shows a similar tendency to the curve calculated by Kurze and Anderson for an incoherent line source.