Reverb sits better in a mix when its pre-delay is timed to the music. This tool turns your BPM into musically-synced pre-delay values so the reverb tail starts on a beat subdivision, keeping the dry signal clear and the wet tail locked to the groove.
How it works
Pre-delay is just a short delay before the reverb begins, so the same tempo-to-milliseconds maths applies. One beat is a quarter note:
quarter note (ms) = 60000 / BPMPre-delays are usually short, so the tool focuses on the shorter divisions — 1/8 down to 1/64 — and gives the straight, dotted, and triplet value for each:
- Straight = the note’s fraction of the beat
- Dotted = base x
1.5 - Triplet = base x
2/3
Worked example
At 120 BPM the quarter note is 500 ms. Useful pre-delays from there:
- 1/16 note:
125 ms— a clear, rhythmic gap - 1/32 note:
62.5 ms— subtle separation, great on vocals - 1/64 note:
31.25 ms— barely perceptible, just adds depth - Dotted 1/32:
93.75 ms— a touch more space with a swung feel
Pre-delay reference at common tempos
| BPM | 1/16 (ms) | 1/32 (ms) | Dotted 1/32 (ms) | 1/64 (ms) |
|---|---|---|---|---|
| 80 | 187.5 | 93.75 | 140.6 | 46.9 |
| 100 | 150 | 75 | 112.5 | 37.5 |
| 120 | 125 | 62.5 | 93.75 | 31.25 |
| 140 | 107.1 | 53.6 | 80.4 | 26.8 |
| 160 | 93.75 | 46.88 | 70.3 | 23.4 |
Pre-delay by instrument type
Different instruments and vocals benefit from different pre-delay amounts. The right choice depends on the tempo, the density of the arrangement, and how upfront you want the source to sit.
Lead vocals: 1/32 to 1/16 note, typically 20–100 ms depending on tempo. The gap keeps each word intelligible before the tail blooms. Too short (under 15 ms) and the reverb smears the attack; too long (over 1/8 note) and it sounds like a distinct echo rather than room ambience.
Snare drum: Short pre-delays of 1/64 to 1/32 (15–40 ms) add space without blurring the crack of the snare. Longer pre-delays on a snare can cause the reverb tail to land in a rhythmically awkward position and mud up the following beat.
Acoustic guitar: A 1/16 to 1/8 note pre-delay creates a sense of room without the reverb washing over the transient detail in the picking or strumming.
Piano: Short pre-delays of 1/32 to 1/16 help each note speak before the reverb fills the space, particularly in dense chord voicings.
Tips and notes
- For lead vocals, a 1/32 to 1/16 pre-delay keeps consonants crisp while the tail adds size; longer than a 1/8 and the reverb starts to sound like a separate echo rather than room ambience.
- On drums, sync the pre-delay to the same division as your delay throws so the ambience reinforces the rhythm rather than fighting it.
- Faster tempos shorten every value — re-check the figure if you change the project tempo mid-session.
- A dotted 1/32 (1.5 times the straight value) adds a slight swing to the onset of the reverb tail that can complement grooves with a triplet feel.
- All values are computed locally in your browser; no data is sent anywhere.