Reverb Pre-Delay Calculator
Pre-delay is the secret to professional-sounding reverb. It's the gap between your dry signal and the onset of reverb — measured in milliseconds. When synced to your song's tempo, pre-delay creates rhythmic space without washing out the mix. Here's the complete guide to calculating and using it.
What Is Reverb Pre-Delay?
In the real world, sound takes time to reach a wall and bounce back. The pre-delay is that travel time. In a large hall, you might hear 30–50ms of silence before the first reflection arrives. In a small room, it's 5–15ms.
In mixing, pre-delay serves two purposes:
1. Clarity. A gap between the dry signal and the reverb lets the transient (the attack of a snare hit or the start of a word) cut through before the reverb swells in. Without pre-delay, reverb can smother the attack and muddy the mix.
2. Rhythmic integration. When pre-delay is set to a musical subdivision of your tempo (e.g., a 16th note), the reverb "breathes" in time with the song. It becomes part of the groove rather than an effect pasted on top.
The Pre-Delay Formula
16th note pre-delay = 60,000 ÷ BPM ÷ 4 = 15,000 ÷ BPM
32nd note pre-delay = 60,000 ÷ BPM ÷ 8 = 7,500 ÷ BPM
64th note pre-delay = 60,000 ÷ BPM ÷ 16 = 3,750 ÷ BPM
Example at 120 BPM:
16th note = 15,000 ÷ 120 = 125 ms
32nd note = 7,500 ÷ 120 = 62.5 ms
64th note = 3,750 ÷ 120 = 31.25 ms
Pre-Delay Quick Reference
Typical pre-delay times for common BPMs and note divisions. Use the interactive calculator for exact values at any BPM.
| BPM | 16th Note (ms) | 32nd Note (ms) | 64th Note (ms) |
|---|---|---|---|
| 70 BPM | 214 | 107 | 54 |
| 80 BPM | 188 | 94 | 47 |
| 90 BPM | 167 | 83 | 42 |
| 100 BPM | 150 | 75 | 38 |
| 110 BPM | 136 | 68 | 34 |
| 120 BPM | 125 | 63 | 31 |
| 128 BPM | 117 | 59 | 29 |
| 140 BPM | 107 | 54 | 27 |
| 160 BPM | 94 | 47 | 23 |
Which Pre-Delay to Use?
🎯 Choosing the Right Pre-Delay
64th note (very short, 15–40ms): The reverb feels "glued" to the source. Use this for tight, modern mixes where you want space without obvious separation. Great for pop vocals and punchy drums.
32nd note (medium, 30–80ms): The industry standard. Enough gap for clarity while keeping the reverb connected. Excellent for lead vocals, snare drums, and acoustic instruments.
16th note (longer, 60–150ms): Creates audible separation between dry and wet signals. The reverb feels like a distinct "space" behind the source. Perfect for ballads, orchestral elements, and ambient textures.
8th note (very long, 120–300ms): Creates a pronounced slap before the reverb. Best for special effects or very sparse arrangements where you want the reverb to be a feature.
Reverb Decay Time Guide
Pre-delay controls when the reverb starts. Decay time controls how long it lasts. Here are standard decay time ranges for different reverb types:
| Reverb Type | Decay Time | Character / Best For |
|---|---|---|
| Hall | 2.0 – 3.5 s | Grand, lush, cinematic. Orchestral music, ambient, ballads |
| Large Room | 1.2 – 2.0 s | Natural spaciousness. Post-rock, worship, jazz |
| Plate | 1.0 – 2.0 s | Bright, dense, musical. Vocals, snare, synths (classic pop sound) |
| Chamber | 0.8 – 1.5 s | Warm, diffuse. Strings, piano, vintage vocal sound |
| Small Room | 0.5 – 1.0 s | Intimate, natural. Drums, acoustic guitar, general glue |
| Ambience | 0.2 – 0.5 s | Barely there. Drum room mics, tight spaces, mix cohesion |
| Gated / Non-Linear | 0.3 – 0.8 s | 80s snare drum, percussive punch, creative effects |
| Spring | 0.5 – 1.5 s | Twangy, characterful. Surf guitar, dub, lo-fi aesthetic |
Genre-Specific Reverb Settings
🎸 Quick Genre Guide
Pop Vocals: Plate reverb, 32nd note pre-delay, 1.2–1.8 s decay. Bright and present.
Rock Drums: Small room or ambience, 16th note pre-delay, 0.5–1.0 s decay. Natural punch.
Hip-Hop Vocals: Plate or chamber, 64th note pre-delay, 0.8–1.2 s decay. Tight and controlled.
EDM Leads: Hall, 16th note pre-delay, 2.0–3.0 s decay. Big, festival-sized space.
Acoustic Guitar: Small room, 32nd note pre-delay, 0.6–1.0 s decay. Natural and intimate.
Orchestral: Hall, 16th note pre-delay, 2.5–3.5 s decay. Realistic concert hall depth.
Common Pre-Delay Mistakes
Too short (0–10ms): The reverb fuses with the dry signal and masks the transient. Your mix sounds distant and washed out. Always use at least 15–20ms of pre-delay unless you're deliberately going for a "swimmy" effect.
Too long (200ms+): The gap becomes a noticeable slapback echo. The reverb feels disconnected from the source. Past 150ms, you're entering delay territory — not pre-delay.
Not syncing to BPM: A random pre-delay value creates rhythmic tension with the song. The reverb onset will fight the groove instead of supporting it. Always calculate from your BPM.
Same pre-delay on everything: Different instruments need different pre-delay times. Vocals typically want shorter pre-delay (32nd note), while drums can handle longer (16th note). Using the same pre-delay on every reverb send creates a flat, one-dimensional space.
Pro Tip: The Pre-Delay + Decay Relationship
The total perceived reverb length = pre-delay + decay time. A hall reverb with a 125ms pre-delay and 2.5s decay feels like 2.625 seconds of space. If you increase pre-delay, you can sometimes decrease decay time to maintain the same perceived reverb length while gaining clarity. This is a powerful mixing trick — more clarity, same spatial impression.
Try the Interactive Reverb Calculator
Get exact pre-delay times for your BPM with our live calculator. Adjust the tempo and see all note divisions update in real time.
Open Reverb Calculator