Reverberation Time

Reverberation time is the duration required for sound energy in a room to decrease by 60 dB after the sound source is turned off. First described by Wallace Clement Sabine in 1898, it remains the foundational parameter in room acoustics. ISO 3382-2:2008 defines the measurement methodology for ordinary rooms. Reverberation time depends on room volume and the total sound absorption present on all surfaces, furniture, and occupants. Short reverberation times (0.3–0.6 s) suit speech-focused spaces like classrooms and meeting rooms, while longer times (1.5–2.5 s) are preferred for music performance. The parameter is always frequency-dependent and should be evaluated across the 125–4000 Hz octave band range.