The functionality of an audio system is often reduced to what three easily understood concepts?

The three core performance attributes of any audio system are intelligibility (clarity of speech), loudness (sufficient sound pressure level), and stability (resistance to feedback). These parameters ensure a usable and effective sound reinforcement system.

“For speech reinforcement systems, performance must be measured by intelligibility, loudness, and system stability. Without all three, usability is compromised.”

— CTS Exam Guide, Audio Systems Design Chapter