The authors conducted various studies, considering the importance of sound absorption design in realizing a comfortable sound environment in a living space. In this study, as a basic study in a real house, we measured the reverberation time, average sound absorption coefficient, and background noise level for three types of rooms: a bedroom, living/dining room, and child’s room in three model houses. In addition, we recorded the sounds in these rooms via binaural recording and conducted subjective experiments using Scheffe’s paired comparison method to analyze the impression of the sound environment in each room. The results obtained were as follows:
1) The reverberation time of the houses surveyed was 0.34–0.51 s in the bedroom, 0.52–0.84 s in the living/dining room, and 0.36–0.67 s in the child’s room. The average sound absorption coefficient was 0.16–0.24 in the bedroom, 0.13–0.18 in the living/dining room, and 0.12–0.21 in the child’s room.
2) As a general tendency of the average sound absorption coefficient, the sound absorption coefficient tended to be low in the band above 500 Hz regardless of the type of room.
3) The test subject was able to evaluate the difference in the sound environment of the room by listening to the sound reproduced from the binaural recording through headphones. Therefore, with regard to the evaluation items used, the sound environment of the actual living space can be evaluated through a subjective experiment using binaural recording.
4) The “sense of silence” and “feeling of serenity” of the sound environment of the room could not be evaluated only by the background noise level, and the effect of the average sound absorption coefficient of the room was significant.
5) Even in an actual house, the impressions of the sound environment due to the difference in the sound absorption coefficient differed significantly. Specifically, bedrooms with higher sound absorption coefficients resulted in a higher “sense of silence,” “feeling of serenity,” and “sense of quality” compared with the living/dining and child’s rooms with lower absorption coefficients.
The results show that a design that enhances the sound absorption coefficient may be able to create a “sense of silence,” “feeling of serenity,” and “sense of quality” in the sound environment of a real house. The experimental results from binaural recordings, including footsteps, suggest that people may evaluate the sound environment of a living space by the indoor sound generated by actions in daily life. This indicates that to realize a comfortable sound environment in a living space, it is important to consider not only a sound insulation that controls the sound from the outside, but also a sound absorption that controls the sound generated indoors.
