Reverberation Time (RT60)
RT60 describes how fast a room decays and is the baseline for judging recording and mixing spaces.
Related
The problem
The same drums sound like a box in a small room and smeared in a hall; no reverb setting fixes it. The room's decay is the usual culprit.
Physics or room
RT60 is the time for sound to fall 60 dB after the source stops. It varies with frequency, usually longer in the bass. Sabine's formula ties it to volume and absorption. Small rooms run 0.2 to 0.4 s, halls 1.5 to 2.5 s; where direct and reverberant sound are equal is the critical distance.
Practice and judgement
Measure first. Use a clap or sweep to plot decay per band and see whether bass rings longer. Treat bass traps, reflections and the rear wall. Aim for even decay, not the shortest number. Keep vocal mics inside that distance.
What to listen for
Clap and hear whether the tail snaps or booms; on speech, check whether consonants smear. Play staccato piano and hear what remains. Walk the room; beyond the critical distance it turns vague.
Common misunderstandings
RT60 is not one number; it changes with frequency, and one figure hides bass problems. Long reverb is not always wrong; halls need it. Carpet absorbs highs, not bass ring.
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- Everest, F. Alton，Master Handbook of Acoustics（McGraw-Hill）— 混响时间与临界距离章节核对，未引用
- Newell, Philip，Recording Studio Design（Focal Press）— 控制室衰减目标章节核对，未引用
Used for fact-checking only; all prose is original.