Because the human ear is better at hearing middle and high frequencies, a room must be more supportive of low frequencies to balance the sounds properly. Walls of this quality were standard construction 100 years ago, which is why performing arts centers built then are lauded for their acoustical qualities. Steel and poured-concrete construction methods have required acousticians to come up with other ways to balance the variety of sounds produced during a symphonic performance. Due to cost considerations, many large performing arts centers are programmed as multipurpose halls. These require acoustical compromises to accommodate the variety of performances.
Orchestral concerts call for reflective surfaces that increase sound's reverberation time.
Opera and theater productions need absorptive surfaces to limit excessive reverberation. To create both qualities in a single hall, acoustical components must be carefully designed. Making these components adjustable, such as curtains, doors, or pivoting panels, means they must be reconfigured and operated properly to address the specific needs of each performance. Computer models and analyses can help acoustical engineers understand the dynamics of these halls. You may apply for credits either by downloading the form and faxing or mailing it, or by completing the electronic version and sending it via the Internet.