Free mixing tool
Delay & Reverb Time Calculator
Enter your song's BPM to get tempo-synced pre-delay and reverb decay times, from a tight ambience to a two-bar hall.
Showing times for 120 BPM.
| Space | Length | Pre-delay | Reverb decay |
|---|---|---|---|
| Hall2 bars | 4000.0 ms | 62.5 ms | 3937.5 ms |
| Large room1 bar | 2000.0 ms | 31.25 ms | 1968.75 ms |
| Small room1/2 note | 1000.0 ms | 15.63 ms | 984.37 ms |
| Tight ambience1/4 note | 500.0 ms | 7.81 ms | 492.19 ms |
| Eighth note1/8 note | 250.0 ms | 3.91 ms | 246.09 ms |
| Sixteenth note1/16 note | 125.0 ms | 1.95 ms | 123.05 ms |
Start here, then adjust by ear. Every song's groove is different.
Why the right pre-delay and decay time matter
Setting the correct reverb pre-delay can be the difference between lush rhythmic clarity and a mix washed out in reverberant clutter. Many professional engineers set their reverb to the tempo of the song, so the reverb moves with the cadence of the track and gives you control over how close or far away a source sounds.
This calculator does the math for you: enter your song's BPM and it shows pre-delay and decay times that fit. Not sure of the tempo? Key Finder detects a track's tempo and key.
How reverb shows up in everyday life
Pre-delay happens around us every day. In almost any space, you hear a short gap before the reverb arrives. That gap is the pre-delay. The values above are commonly used starting points for pre-delay and decay, so your reverb feels natural.
An easy example
Tempo: 120 BPM
Small room (1/2 note): 1000 ms total length
Pre-delay: 1000 ÷ 64 = 15.63 ms
Decay time: 1000 − 15.63 = 984.37 ms
How it works
The pre-delay column divides each length by 64, which is a good starting point. If the pre-delay feels too long, try halving it; if it feels too short, try doubling it.
Then set the decay to fill the gap between the pre-delay and the total reverb length: total length minus pre-delay. For a small room built on a half note at 120 BPM, that's 984.37 ms.
Trust your ears
These numbers take the tedious math off your plate, but no two songs are the same. Groove, feel and swing can't be captured in a calculated number. Use the calculator to lock in a starting point, then let your ears make the final call.