70V / 100V — Constant-Voltage Distributed Audio
70V (and 100V) distributed audio systems allow a single amplifier to drive many speakers over long cable runs without impedance-matching calculations, using transformer-coupled taps at each speaker.
glossaryaudiodistributed-audioamplifiersinstalled-sound70v
RT60 — Reverberation Time
RT60 is the time in seconds for a sound to decay 60 dB after the source stops — the primary acoustic measurement that determines whether a room is suited for speech, music, or neither.
glossaryaudioacousticsrt60speech-intelligibilityinstalled-sound
STI — Speech Transmission Index
STI is the standard objective measure of speech intelligibility in a room — a value from 0 to 1 that predicts how clearly spoken words will be understood by listeners, accounting for reverberation, noise, and system distortion.
glossaryaudioacousticsspeech-intelligibilityconferencinginstalled-sound