1996 Volume 61 Issue 486 Pages 1-7
The purpose of this study is to make clear the relation between the shape of balcony and acoustical properties under the overhang, and ultimately to derive a design criteria for balcony configuration in auditoria. On the assumption that a physical change of sound field caused by building a balcony would be primarily a reduction of the reflected energy from upside, directional characteristics of early reflections afe measured in auditoria both with and without a balcony. And the subjective effectof reflections arriving from upside on auditory envelopment is psycho-acoustically examined in this paper. The conclusions are as follows : (1) The results of measurement show that the ratio of vertical component to total early reflection energy is extremely small under the overhang. (2) Auditory envelopment becomes weaker as the vertical component of reflected energy decreases when lateral energy fraction is constant. These results suggest that the lack of early reflections from ceiling above main orchestra causes the peculiarity of directional distribution of reflections, and consequently disturbs good acoustics under the balcony.
