Perceptual assessment of indoor water sounds over environmental noise through windows

Indoor water sounds were examined in terms of perceptual enhancement of environmental noise through openings for natural ventilation. An experiment was conducted using a simple indoor water fountain system with forty participants (18 women and 22 men) aged between 19 and 27 in an environmental chamber. The indoor water sound levels were varied from 35.8 dBA to 59.8 dBA. Environmental noises transmitted through windows in the living rooms of actual residences were measured and classified into traffic and railway noises and their levels were between 43.0 dBA and 62.1 dBA. The subjective judgment obtained from laboratory experiments showed that the introduction of water sounds resulted in an improvement of environmental noise entering through windows according to water sound level in four psychoacoustical characteristics, where the perception of annoyance reduced and that of pleasantness, calmness and naturalness increased. Pleasantness was the most sensitive characteristic, and noisiness and loudness were the least sensitive characteristics describing the indoor water effects among the six psychoacoustical characteristics used. In terms of gender difference, it was found that women were more perceptive to the introduction of water sounds than men in the parameters of noisiness, loudness and annoyance.