What RT60 means
Reverberation time, or RT60, is how long a sound takes to fade by 60 decibels. In a meeting room a long reverberation time makes speech harder to follow and makes remote participants sound distant. Small meeting rooms work best at about 0.5 seconds or less, and larger ones at about 0.6 seconds.
The estimate uses the Sabine formula with typical absorption values for each finish. The clap test records the room’s actual decay and works it out at 500 Hz and 1 kHz; measure from two or three places for a reliable average.
Questions
What is a good RT60 for a meeting room?
About 0.5 seconds or less for small rooms and 0.6 seconds for larger ones. Above that, speech and video calls start to suffer.
How accurate is the clap test?
It’s a good practical check when the clap is loud above the background noise. For formal acoustic reports, use a calibrated measurement microphone and test signal.
What’s the best way to reduce echo?
An acoustic ceiling is usually the biggest single improvement, followed by wall panels on the side and back walls.