## ACOUSTICAL CORRECTION OF UNDER BALCONY CAVITIES IN THEATHER HALLS ON A HORSESHOE-SHAPED PLAN

TADEUSZ KAMISIŃSKI, JERZY WICIAK

Department of Mechanics and Vibroacoustics, University of Science and Technology

AGH al. Mickiewicza 30, 30-095 Kraków, Poland. kamisins@agh.edu.pl

In theaters where audience halls are built on horseshoe-shaped plan the ceiling of the area under balcony at the back of the hall is relatively low. Most people seated there experience poor reception. Efforts have been made to formulate general guidelines addressing that problem. Acoustical measurements of several halls have been performed together with computer simulations of sound field. In the computer model, acoustical data of finishing materials and acoustical structures obtained from laboratory tests have been used. In particular, QRD sound diffusing structures have been examined. Those structures were designed specifically for the halls. In all cases the simulations showed improvement of acoustical parameters.