ROOM ACOUSTICAL PARAMETERS AS INDICATORS OF SHORT-TERM ACOUSTIC COMFORT IN INNER YARDS

摘要

Urban living in areas with a high population density is affected by classic noise sources, such as road traffic, railways, and aircraft noise, as well as by surrounding everyday life sounds. Noise assessment and noise control are usually dealt with by methods of environmental and construction acoustics, whereby the goal is to reduce the noise immission at the living space of the residents. However, beyond the noise immission, there has been an increasing interest in soundscape design with the aim to improve the soundscape and acoustic comfort or pleasantness. Whereas residents of housing complexes (with shared inner yards) in urban areas might benefit from an improvement of the soundscape, the question is to what extent classic room acoustical parameters would describe/predict such possible improvements. Three laboratory experiments are presented here, in which the individual and combined effects of a series of independent variables (such as facade absorption, sound source, observer position and etc.) on short-term acoustic comfort were investigated. Virtual inner yards were designed with the software ODEON. Single-channel recordings were fed into the inner yard ODEON room acoustic simulation, whereby a 2D spatialization was carried out for a playback over five loudspeakers in the laboratory. Moderate facade absorption was found to increase acoustic comfort. Pleasant and unpleasant sounds were associated with comfort and discomfort, respectively. Acoustic comfort differed for distinct observer positions, whereby positions with high sound pressure levels and/or those exhibiting strong flutter echoes were found to be associated with lower comfort ratings. A post hoc analysis was carried out (beyond the experimental design), by which classic room acoustical parameters were analyzed in their ability to function as indicators for acoustic comfort/discomfort.