Reverb Time Calculator
Enter your song's tempo and get tempo-synced pre-delay and decay times for hall, room, and tight reverbs — so the tail breathes with the track. Based on Bobby Owsinski's method.
Hall
Room
Tight
Bar lengths assume 4/4 time. Pre-delay + decay = the target length, so the tail dies right on the musical boundary.
Why time the reverb to the track
Reverb doesn't just add space — it adds length to every sound it touches. If the tail is still ringing when the next snare lands, the two smear together, the groove clouds over, and your only fix is turning the reverb down until it barely registers. Time the tail so it dies just before the next hit, and the mix stays clean while the reverb can sit surprisingly loud.
Mixing engineer and author Bobby Owsinski teaches a simple way to get there, in The Mixing Engineer's Handbook: treat pre-delay plus decay as one musical length. For a big hall, make the total last one bar (240000 ÷ BPM ms in 4/4). For a medium room, half a bar. For tight ambience, a quarter bar. Set the pre-delay to roughly a 1/64 note first, then stretch the decay to fill the rest.
Pre-delay is the underrated half of the trick: that short gap separates the dry signal from the wet tail, keeping vocals upfront and intelligible even inside a big reverb. Longer pre-delay pushes the room further behind the singer; shorter glues them together.
How to dial it in
1. Set the pre-delay
Start at the 1/64-note value. If the source needs to sit closer to the listener (lead vocal), try lengthening toward a 1/32; for glue on a bus, shorten it.
2. Time the decay
Set the decay so pre-delay + decay lands on the bar (or half bar). Solo the snare with the reverb and listen: the tail should exhale fully just before the next hit lands.
3. Adjust by feel
These are starting points. Ballads often want the tail to hang past the bar; dense uptempo tracks may need it shorter. If the groove starts clouding, shorten the decay before reaching for the level fader.
Frequently asked questions
How do I set reverb time to the tempo of a song?
Time the whole reverb — pre-delay plus decay — so it ends on a musical boundary. For a big hall, aim for one bar total; for a medium room, half a bar; for tight ambience, a quarter bar. One bar in 4/4 lasts 240000 ÷ BPM ms. Set pre-delay to roughly a 1/64 note and let the decay fill the rest.
What pre-delay should I use on reverb?
A good tempo-synced starting point is a 1/64 note — about 31 ms at 120 BPM. Pre-delay separates the dry sound from the tail, keeping the source upfront and intelligible while still sounding spacious. Longer pre-delays push the reverb further behind the vocal; very short ones glue it to the source.
Why does timing the reverb to the tempo matter?
A tail that dies just before the next beat makes room for the rhythm to punch through, so the mix stays clean even with generous reverb. A tail that carries over the next hit smears the groove and forces you to turn the reverb down. Timing the decay to the tempo — an approach popularized by Bobby Owsinski — lets the reverb sound big without washing out the mix.
Is the reverb time calculator free?
Yes. It's completely free with no sign-up and runs entirely in your browser. Nothing is uploaded — you just type a BPM and read the millisecond values.