Jaffe Holden Acarbrough Acoustics, Inc., 114 A Washington St., Norwalk, CT 06854
In the early sixties, the American Symphony Orchestra League conducted a survey of American orchestras to determine their preference of material for demountable symphonic enclosures. Oddly enough, Fiberglass reinforced polyester shells manufactured by Stagecraft Corporation received the number one rating in the country. The Stagecraft shells, constructed of 0.0625- to 0.125-in. Fiberglass sheet, and edge framed in aluminum, were coupled to stage house volumes through openings between the ceiling sections. In the low frequencies some coupling was achieved through the panels themselves, in view of their low transmission loss at the bottom end of the spectrum. This paper will document the success of these enclosures, and explain why these shells worked so well for orchestras performing in the sixties and seventies. Basic changes in multi-use theater design in the eighties reduced the effectiveness of these designs. However, several practitioners have developed new design solutions that have returned stage house coupled shells to the forefront once again.