Half of the complaints against low frequency sound are structural one, such as rattling doors or windows. This paper describes about the laboratory experiments concerning rattling of doors or windows generated by infra and low frequency sound. The results are shown as follows. (1) The threshold sound pressure levels of rattling doors and windows (hereinafter called TSR) are varying widely, (2) TSR are determined by many factors; frequency of infra and low frequency sound, mass of the door or the window, type or variety of them, clearance between the door and the frame, and so on. But, the most important factor is the shutting condition of the door or the window, (3) The “average-S.D.” of TSR on each frequency for all data; (Lrat, ave-S.D.) were calculated, Lrat, ave-S.D. showed a good correlation with “rattling threshold”, proposed in 1977, between 10 to 30Hz, (4) By comparing the results of field measurements and the experimental level (Lrat, ave-S.D.), it became clear that the most of all sound pressure levels where structural complaints occurred, distributed above Lrat, ave-S.D..
A type of highway noise barrier is designed to possess both acoustical and non acoustical benefits such as amenity for residents and drivers. One idea for the non acoustical benefit is to apply apertures to barriers. In the design, absorptive louver blades are applied to barriers so that the acoustical performance of the barrier can be improved. The barrier, i.e., horizontal louver, looks like sun shading blinds. The acoustical performance of this type is examined by scale model experiments and calculated by two-dimensional BEM. Trial products of horizontal louver are made in full scale and the efficiency of barriers against the highway noise is investigated at a place where an elevated road is simulated. Test results show that noise reduction of 2dB over conventional barrier is obtained.