This is the oral paper of a plenary lecture presented at the opening ceremony of the Joint meeting of the Acoustical Societies of Japan and America. The paper has briefly reviewed the update of both public and personal aspects of “Environmental acoustics.” Although it has interdisciplinary or multidisciplinary nature, it is limited arbitrarily to those aspect related to people's daily lives, particularly those in which the author has an interest. The environment can be defined as the interface between human beings and everything surround-ing them, i.e. the human Psycho-physiological factors and surrounding Physical factors. Therefore it seems to be imperative to promote Psycho-physiological research for developing environmental acoustics.

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The authors have proposed a technical prediction model of auditory source width (ASW). In this model, ASW for any stimulus can be estimated by summing up the 1/3 octave band ASW multiplied by the weighting factor W. In the previous paper, the validity of the model was confirmed for the condition that the number of adjacent bands was two and each band had equal band levels. In this paper, the validity of the model is examined when the number of adjacent bands is two and each band has different band levels. The results of the psychological experiments show that the model is valid even when the level of each band is different. It is also shown that W depends on the combination of the band levels of the stimuli. Both W for the higher band and W for the lower band change monotonously with the level difference between the bands. The average change of W is about 0.3/10 dB.

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Transmission of correct speech in underground is essential to keep people safe in case of emergency. On the other hand, sound propagation characteristics is influenced by acoustical conditions of the sound field. From the viewpoints, sound propagation experiments, hearing tests of speech by subjects and measurements of RASTI are conducted in a reverberant curved tunnel. From measurements of pink noise propagation, relative attenuations less than 315Hz are much small, and those at higher frequencies rapidly increase with distance. The attenuations may be influenced by not only absorption characteristics but also the curved feature of the tunnel. While hearing scores of speech decrease with distance, differences between the scores are observed and may depend on the kinds of speech. From analyzing the hearing results, mistakes are occurred by influences of both reverberant condition near the sound source and degradation of signal-to-noise ratio of speech signal due to many times of reflection at further points. Positive correlation is observed between RASTI and scores of the articulation syllables. Relationships between RASTI and scores of the other speech are indicated through the results of articulation tests. Possibility on prediction of speech transmission by the objective physical measurements is suggested.

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