Absorption of Adjoining Volumes in Reverberation Calculations

Abstract

Theatres with balconies present a different aspect to reverberation calculations than the single volume type. The space under a balcony may contain more absorption in square feet of equivalent open window space than the area of the face opening into the main volume. Heretofore arbitrary values ranging from .25 to 1 have been assumed for the coefficient to assign this connecting area. To obtain a more accurate idea of the absorption effective in the main volume random distribution of sound energy was assumed and equations were derived expressing the percentage absorbed of the energy incident on the area. The apparent coefficient is a function of the average coefficient behind the area and the ratio of the area to the total surface enclosing the space in question, and is different for different assumptions made as to the manner in which reflections occur. The use of the coefficient in reverberation calculations is discussed.