Acoustical design of classrooms and lecture theatres is of paramount importance in meeting the required speech intelligibility rating for Post secondary educational facilities. In a facility intended for learning, new information is being delivered in such density that you can't afford to have marginal speech intelligibility. Poor acoustics will degrade speech intelligibility for people who have a common first language, but for people who are learning in a second language, the need for shorter reverberation time and lower background noise becomes even more important. The same stringent criteria also need to be applied to meet the requirements of disability access for the hearing impaired.

Many colleges and universities have been surprised to learn how poor the acoustics are in their existing facilities. We have participated in the measurement, analysis and subsequent design of acoustical upgrades of lecture rooms and theatres across Western Canada. It isn't just the 200+ seat lecture theatres that are a problem, it extends right down to the 30 seat classrooms. The problems can exist in buildings constructed from 1940 to now, as the acoustical elements that made classrooms work effectively were not always understood by room designers. At one time the belief was that a long reverberation time helped improve the level of speech, now it is known that early reflections arriving within the first 35/100 of a second can help improve speech intelligibility and level, but late reflections and excessive reverberation can degrade intelligibility. Excessive background noise levels from HVAC systems or exterior sources such as traffic will also seriously degrade intelligibility, even where the reverberation is suitable. Between these two important parameters of excessive reverberation and background noise, many classrooms and lecture theatres receive their failing grade.