What STI Score Means Good Speech Intelligibility?

Understanding STI scores is essential for evaluating speech system performance in venues where voice communication matters. The Speech Transmission Index, defined by IEC 60268-16, provides a single number between 0 and 1 that quantifies how well speech can be understood through an electroacoustic system or in a room. These questions cover the rating scale from Bad to Excellent, what STI values are acceptable for different venue types such as classrooms, courtrooms, and transit stations, and practical methods to improve intelligibility scores.