A note on the importance of room cross-section in concert halls

Abstract Spatial responsiveness (SR) is identified as a desirable property of concert halls usually associated only with classical rectangular concert halls. Two halls, of classical and modern shape, are compared, and their echograms are subjected to a masking analysis based on the work of Seraphim. From masking consideration it is concluded that SR occurs in halls in which masking of one or more major reflections by others is a minimum because (a) no two reflections of the same direction in the first 100 msec after the direct sound are temporally adjacent, (reflection here includes the direct sound); (b) the major reflections (skeletal reflections) are not bunched but tend toward even spacing after the direct sound. Some architectural conclusions are drawn relating room cross-section to orchestral width, and these are compared with experience in existing halls.