Listening laboratory study of low height roadside noise barrier performance compared against in-situ field data

A listening laboratory study conducted using simulated soundfields with and without a low (1 m) height roadside noise barrier suggested that small but significant improvements in the perceived or subjective soundscape could be achieved. The laboratory study closely replicated the acoustic conditions observed in an earlier in-situ field study (Rådsten-Ekman et al. [18]) which had also found similar improvements in subjective impressions. Comparing the two sets of data suggested that the modest acoustical performance of the low height road traffic noise barrier was sufficient to explain the observed subjective differences. In the laboratory study, reported loudness and annoyance were reduced by up to 25% and reported calmness was increased by up to 43%. In the laboratory study, there was no indication that the increased relative importance of low frequency content within the overall frequency spectrum behind the noise barrier had any material effect on the results.