acoustical engineering

…centred on the problem of acoustics in the ancient theatre. The difficulty in achieving audibility to an audience of thousands, disposed around three-fifths to two-thirds of a full circular orchestra in the open air, seems to have been insoluble so long as the performer remained in the orchestra. A more…

…of the structure, by elaborate acoustical filters in the ventilating ducts, and by thick masonry walls. Interior surfaces are covered with absorptive material, such as glass fibre or mineral wool in blankets or in horizontal and vertical wedges. Ceiling and floor are similarly padded; a thin steel mesh just above…