Use of the rapid speech transmission index for investigating an intelligibility problem in an Orthodox Jewish Temple

An Orthodox Jewish Temple has unique problems ensuring excellent speech intelligibility. A portion of the religious service is led by an individual who faces the front of the temple at a podium some way back from the front of the room. Religious principles forbid use of an electronic speech reinforcement system; therefore, excellent acoustics are required. An investigation of a temple having complaints of poor intelligibility was undertaken using an instrument which measures the rapid speech transmission index (RASTI). The instrument provided an objective evaluation of the existing speech intelligibility throughout the temple, and it also indicated the extent to which background noise (HVAC system) and reverberation were responsible for reduced intelligibility. To improve intelligibility, small reflecting panels were held above the various speaking positions and objectively evaluated using the instrumentation. The location and angle which provided the highest RASTI value were easily determined in real time. This proved much more effective than traditional geometric acoustics techniques.