Abstract:

``The most important function of sound in theater is to ensure audience comfort in perceiving audio component of a performance'' [Bracewell, Sound Design of Theater (1993)]. Background research has unveiled poor speech intelligibility at the Gammage Auditorium. This study aims to map speech intelligibility in different seating areas and measure the factors causing poor speech intelligibility. The instrument used to collect data will be the Techron TEF System 12 analyzer. This instrument uses modulation transfer function (MTF) and speech transmission index (STI) techniques. This is based on RASTI techniques by measuring the reduction of signal modulation in an acoustic transmission path [Keele, Jr. (1988)]. MTF is a measure of how well the amplitude modulation of a signal is preserved when a signal is sent from one point to another. The measurement modulations at different frequencies are converted to a single value that indicates the speech intelligibility in the auditorium. This single value is STI. Measurements are also provided on data for signal-to-noise ratio and RT[inf 60]. A separate measurement of background noise level would indicate poor speech intelligibility due to excessive reverberation or background noise.