Reverberation (RT60)

Reverberation time is how long sound takes to decay by 60 dB. A hard-surfaced workshop rings, which raises the overall noise level and wrecks speech clarity. Sabine gives T = 0.161 V / (S·α) — doubling the absorption halves the time.

Sabine assumes a diffuse field and reasonably even absorption; it over-predicts in very absorbent rooms (use Eyring there) and in long, narrow or heavily furnished spaces. α varies strongly with frequency — quote the band you used.