Reverb Pre-Delay Calculator
Reverb pre-delay is one of the most effective techniques for keeping vocals and lead instruments audible while still adding depth and space. By delaying the reverb onset by a short amount, the dry transient lands clearly before the reverb cloud arrives. Setting pre-delay to a rhythmic subdivision keeps it musically coherent. This calculator converts tempo (BPM) and note subdivision into pre-delay time in milliseconds. A 1/32nd note at 120 BPM is 62.50 ms; a 1/64th note is 31.25 ms, both common and practical vocal pre-delay values.
Reverb pre-delay formula
Pre-delay (ms) = 60,000 / BPM * note_fraction
Quarter = 1.0, Eighth = 0.5, Sixteenth = 0.25
Thirty-second = 0.125, Sixty-fourth = 0.0625
Dotted eighth = 0.75
This is identical to the BPM-to-delay formula used for delay plugins. The quarter-note beat is 60,000 / BPM milliseconds. Multiply by the note fraction to get any subdivision. Dotted values are 1.5 times the base note.
Recommended pre-delay ranges
- Under 15 ms: very tight, blends with the signal, can cause comb filtering at shortest values.
- 15 to 30 ms: natural, creates intelligibility without obvious separation.
- 30 to 60 ms: clear separation, often used on lead vocals and solo instruments.
- Over 60 ms: distinct slap effect before reverb; dramatic for special effects.
- Common choice: 1/32nd note at the song's tempo (typically 20 to 80 ms range).
Reverb pre-delay: frequently asked questions
What is reverb pre-delay?
Pre-delay is a short gap between the dry signal and the onset of the reverb tail. It separates the source from the reverb, making vocals and instruments clearer and more intelligible while still providing a sense of space. Typical values are 10 to 60 ms.
Why set pre-delay to a tempo-based value?
Tempo-synced pre-delay keeps the reverb tail rhythmically locked to the song. If the reverb begins on a rhythmic subdivision, it sounds intentional rather than random, integrating better into the groove. A 1/32nd or 1/16th note pre-delay is a common starting point.
What pre-delay value should I use for vocals?
For lead vocals, 20 to 40 ms is a common starting range. A 1/16th note at 120 BPM = 125 ms is too long for most situations. A 1/32nd note (62.5 ms) or 1/64th note (31.25 ms) are more practical. Adjust by ear while the track plays.
How does pre-delay affect perceived room size?
Longer pre-delay makes the reverb sound as though the reflecting surface is farther away, creating the impression of a larger room. Very short pre-delay (under 10 ms) blends into the direct sound and can cause comb filtering. Values of 15 to 30 ms suggest a medium-large room.
Is pre-delay the same as reverb onset?
Yes. Pre-delay delays the entire reverb tail, including early reflections, by a fixed number of milliseconds. Some reverb plugins have a separate early reflections delay and a pre-delay for the diffuse tail; in that case they are distinct parameters.
Official sources
- Audio Engineering Society (AES): aes.org - reverb and room acoustics standards.
- MIDI Association: midi.org - MIDI tempo and timing specifications.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.