The seismic upgrade renovation of the University of British Columbia's aging 500 seat Hebb Theatre provided the opportunity to upgrade the nearly five decade old room acoustics. Built in the late 1940's, the all plaster construction provided a uniform 2.0 second reverberation time that made the room virtually unusable with less than 300 students in the room. The sound system was a pair of very old column speakers augmented by re-entrant horns. The speech intelligibility measurements of the original construction came up as a Speech Transmission Index (STI) of 0.41-0.45 (equal to %ALCONS of 18%, a very Poor rating) with or without the sound system.

The acoustical renovations involved the addition of absorption to bring the reverberation time down to 1.0 second (unoccupied), bringing the unaided STI up to 0.61-0.64 (equal to %ALCONS of 6%, which is a Fair rating) and the reinforced STI up to 0.65-0.71 (equal to %ALCONS of 3.8%, a Good rating). The addition of students will improve the acoustical environment even further. The drop in reverb time also improved the noise control in the space. Absorption was carefully applied to surfaces near the lecturer's position at the front of the room. Reduction of reverb time and the control of reflections near the open microphones improved gain before feedback, especially with a wireless lavalier system.

The sound system was upgraded using a small centre cluster for the front 2/3 of the room, with delayed infill speakers provided for the rear 1/3 of the seats. Using the computer model we found that it was not possible to get uniform frequency response in the rear of the room from the centre cluster since the theatre is quite deep and steeply raked. We also specified a new video presentation system that included an 1100 ANSI lumen output light valve video projector to provide the image size and brightness needed. The light valve projector is used for computer graphics and video presentations, and it augments two existing high output overhead projectors. We designed a vandal and theft resistant video copystand that has been constructed to replace or augment one of the overhead projectors. A touch screen control system provides a convenient control interface for the users.