A proposed acoustical renovation for The Great Hall at The Cooper Union.

Abstract

The Great Hall is an 1100-seat auditorium with historical landmark status built in 1859. It has been the site of many historic speeches by figures ranging from President Abraham Lincoln to Sioux Chief Red Cloud. Throughout its history, however, The Great Hall has been described as a less than adequate acoustical environment, suffering from low speech intelligibility and excessive reverberance. Building upon the previous work of Raichel and Dragan who modeled the auditorium in its current configuration, the authors undertook a study of the feasibility of renovating and improving The Great Hall while maintaining the architectonic integrity of the space, as necessitated by historical landmark protection. It was found that a simple replastering of the walls and ceiling of the auditorium will lower the reverberation time at 250 Hz from over 3 s to under 1 s and should significantly reduce the effect of late (after 50 ms) reflections. The new plaster will have lower density and higher porosity than the old plaster, significantly improving its sound-absorbing characteristics. The proposed renovations are currently under consideration for implementation.