Reverb Pre-Delay Calculator
Calculate tempo-synced pre-delay values across every musical subdivision. Preserve transient punch on drums and vocal consonant clarity with mathematical accuracy.
Pre-Delay Calculator Widget
Enter your session BPM to calculate musical pre-delay durations in milliseconds.
| Subdivision | Multiplier | Duration (ms) |
|---|
What Is Reverb Pre-Delay?
Reverb pre-delay is the time offset (measured in milliseconds) between the direct acoustic arrival of a dry sound source and the onset of the first early reflections generated by a physical boundary or reverb plugin. In acoustic physics, sound travels at roughly 343 meters per second (approx. 1.13 feet per millisecond), requiring measurable time to travel from the sound source to distant walls and bounce back to the listener.
In modern digital mixing, setting pre-delay allows dry transients (such as the strike of a drumstick on a snare head or the initial consonant of a vocal syllable) to pass through completely clean before being surrounded by the reverberant space.
The Pre-Delay Mathematical Formulas
Quarter Note (ms) = 60,000 ÷ BPM
// 2. Common Pre-Delay Subdivisions
1/32 Note (ms) = Quarter Note ÷ 8
1/64 Note (ms) = Quarter Note ÷ 16 // Golden vocal starting point
1/128 Note (ms) = Quarter Note ÷ 32 // Fast drum/transient starting point
1/64 Triplet (ms) = (Quarter Note ÷ 16) × (2/3)
Worked Mathematical Examples Across 5 Tempos
| Tempo (BPM) | 1/128 Note (Fast Snare) | 1/64 Note (Lead Vocal) | 1/64 Triplet (Swing) | 1/32 Note (Ballad Depth) |
|---|---|---|---|---|
| 80 BPM | 23.44 ms | 46.88 ms | 31.25 ms | 93.75 ms |
| 100 BPM | 18.75 ms | 37.50 ms | 25.00 ms | 75.00 ms |
| 120 BPM | 15.63 ms | 31.25 ms | 20.83 ms | 62.50 ms |
| 140 BPM | 13.39 ms | 26.79 ms | 17.86 ms | 53.57 ms |
| 160 BPM | 11.72 ms | 23.44 ms | 15.63 ms | 46.88 ms |
Practical Applications in Your DAW
- Lead Pop Vocals: Use a 1/64th note pre-delay (
25–40 ms). This pushes the reverb behind the singer so the vocal sounds intimate, upfront, and intelligible. Read our in-depth Guide on Setting Reverb Pre-Delay. - Snare Drums: Use a 1/128th note pre-delay (
12–20 ms). The transient snap cuts through before the snare chamber explodes. See our Drum Reverb Guide. - Acoustic Strings & Pads: Use 0–10 ms pre-delay to allow the instrument to melt organically into the background.
Common Mistakes & The Slapback Threshold
The human auditory system perceives reflections occurring within 30–50 ms as integrated acoustic resonance (the Haas effect). If pre-delay is set beyond 70–100 ms, the brain decouples the reverb and perceives it as a distinct slapback echo. If you want discrete echoes, use our BPM Delay Calculator instead.
Frequently Asked Questions
Reverb pre-delay is the time interval (in milliseconds) between the direct dry audio signal and the onset of early acoustic reflections. It creates acoustic separation, keeping upfront vocals and drums distinct from the background reverb space.
Divide 60,000 by your song BPM to get the quarter-note duration. Then divide by 16 for a 1/64-note pre-delay, by 8 for a 1/32-note pre-delay, or by 32 for a 1/128-note pre-delay.
If pre-delay exceeds 60–80 ms, the human brain stops integrating the reflections as a unified acoustic space and instead hears a distinct, distracting slapback echo.
A 1/64-note pre-delay (typically 20–45 ms depending on tempo) is the industry standard for lead vocals, allowing consonants to cut through before the reverb tail blooms.
Related Audio Calculators & Guides
BPM Reverb Calculator
Master tempo-synced calculation engine for pre-delay and RT60 decay.
Decay Time Calculator
Calculate RT60 decay times matched to 1-bar and 2-bar intervals.
BPM Delay Calculator
Calculate synced delay times for dotted 1/8th notes and slapbacks.
BPM to Milliseconds
Convert any tempo into standard, dotted, and triplet millisecond values.
How It Works
Complete documentation of all acoustic and musical math formulas.