Loudness experiment on general environmental noises considering low-frequency components down to infrasound

Abstract

Wind turbine noise has become a serious environmental noise issue. To investigate this problem, a research project has been conducted over the three years from fiscal year 2010. In this project, experimental studies on human auditory sensation of wind turbine noise have been conducted together with field measurements and social surveys. Since wind turbine noise is often argued to be a low-frequency noise issue, the experiments were conducted with emphasis on the low-frequency components of wind turbine noise. Among them, an auditory experiment was performed to investigate noise indicators suitable for the assessment of wind turbine noise. In this experiment, not only wind turbine noise but also various environmental noises that were recorded so as to include low-frequency components down to infrasound were reproduced down to 4 Hz and loudness tests were performed. The experimental results were evaluated using the A-and C-weighted sound pressure levels, Zwicker loudness level, and Moore-Glasberg loudness level. It has been found that the A-weighted sound pressure level is a simple and appropriate indicator for the loudness assessment of general environmental noises. In addition, the relationships between the noise indicators are discussed on the basis of the results of numerical investigations.

Sleep Disturbance Caused by Step Changes in Railway Noise Exposure and Earthquakes

“…The level differences between the outside and inside for road traffic noise are estimated to be around 10 dB when windows are open and 25 dB when windows are closed in typical Japanese houses [ 23 ]. Since Shinkansen noise has almost the same frequency characteristics as road traffic noise [ 24 ], the level differences for window opening and closing may be similar to those of road traffic noise. As a result, indoor noise exposure likely decreased by more than 10 dB due to the windows being closed.…”