Reverb timing calculator
Translate BPM into candidate pre-delay and decay spans. Pick by ear; the grid only keeps the timing musical.
Did this calculator give you what you needed?
What could be better?
A timing reference, not a mixing prescription
Short subdivisions can be tested as pre-delay candidates; beats and bars can be tested as decay spans. Room, arrangement, source and intent still determine whether a setting sounds right.
Why bars are configurable
The bar values use the beats-per-bar number you enter. A 3-beat bar at 120 BPM is 1,500 ms; a 4-beat bar at the same tempo is 2,000 ms.
How the two settings do different jobs
Pre-delay is the silence between the dry sound and the first reflections, and it is what keeps a vocal intelligible inside a long reverb. Short values, in the tens of milliseconds, read as a bigger room; syncing pre-delay to a sixteenth or a thirty-second note keeps the onset tidy at fast tempos.
Decay is how long the tail takes to fade, and tying it to the grid is what stops a reverb from smearing across the next chord. A tail that ends just before the following downbeat leaves the arrangement room to breathe, which is why the bar and beat values are the ones worth trying first.
Frequently asked questions
What pre-delay should I start with?
For a vocal, somewhere between 20 and 60 ms is the usual starting range: enough separation for the words to stay in front, not so much that the reverb sounds like a separate event. Take the nearest short subdivision from the grid, then move it by ear. At 120 BPM a thirty-second note is 62.5 ms and a sixteenth is 125 ms.
How long should the decay be?
Long enough to sound like a space, short enough to be gone before the next chord. Starting from one bar and shortening is a reliable method: at 120 BPM in four, a bar is 2,000 ms, and pulling the tail back to a half note leaves 1,000 ms of decay with clear space before the next downbeat.
Is decay time the same as RT60?
In most plug-ins yes, near enough. RT60 is the time a sound takes to fall by 60 dB, and it is the parameter that decay or time usually sets. Some designs label the same control differently, and convolution reverbs get their tail from the impulse response rather than from a time you dial in.
Does the pre-delay count towards the decay?
Not in this grid, and usually not in the plug-in either. Pre-delay pushes the whole tail later, so the reverb finishes at pre-delay plus decay. When you are fitting a tail into a bar, subtract the pre-delay from the span you were aiming for.
Does the beats-per-bar field handle unusual time signatures?
Yes, it takes any whole number from 1 to 32, so 3 for a waltz, 5, 7 or whatever the section is in. It counts the beat you are working in: a 6/8 section counted in two dotted-quarter beats is entered differently from one counted in six eighths, so enter the pulse you actually feel.
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